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Institutional cooking with solar energy: A review
Abstract
A review on various aspects of institutional solar cooking is presented. Starting with an overview of energy requirement for cooking, the review includes cooking technologies developed for institutional solar cooking, polices and programs for their promotion and case studies reported in the literature on field level application. State of the art concentrating solar technologies suitable for institutional level cooking includes Parabolic dish, Scheffler dish and ARUN® dish. Design, construction and operational details of both direct and indirect types of concentrating solar cookers have been discussed. The case studies, mainly from India, included provide useful feedback on the experiences of using large scale institutional solar cooking systems. A Few installations of each type of solar cooker have been reviewed and major findings and observations on various aspects of the same are reported.
... 31,32 Various strategies and policies have been developed and put into effect globally to encourage and accelerate the usage of solar cooking devices, particularly among the low-income population. In countries like India, where solar energy (horizontal radiation) is received, it remains between 4 and 7 kWh/m 2 /day, 33 which can make cooking highly economical. 32 Numerous investigations on solar cooking technologies have recently been undertaken in India and the Sub-Saharan region. ...
... The majority of beneficiaries of the installed systems reside in African and South Asian countries. 33 There are many factors that influence the rollout and social acceptance of renewable energy cooking devices. 36 A comprehensive evaluation of solar cooking systems is required in order to simplify decision-making and to inspire a greater interest in their adoption among institutional and community kitchens. ...
... The steam produced by solar energy will replace an equivalent quantity of steam produced by conventional fuel, resulting in yearly monetary benefits (B a,m ), as expressed in Equation (1), 33 : ...
Residential cooking with non‐renewable energy sources, such as firewood, charcoal, natural gas, participate in the emission of more than a gigaton of CO2 per year, which represents 2% of the global CO2 emissions. Additionally, toxic particles including sulfur dioxide, carbon monoxide, and mercury are released leading to elevated levels of indoor air pollution, and adversely affecting the health of the inhabitants. The residential sector's non‐renewable energy cooking devices also pose significant problems, consuming approximately 30%–40% of global energy usage, with over 80% dedicated to cooking applications. To mitigate the negative impacts of traditional cooking on health and the environment, various renewable energy‐based cooking technologies have been developed recently. The primary contributions of our paper are to: (a) present a comprehensive review of concentrated solar thermal cooking technologies, assessing their social, economic, and environmental impact across different climatic zones in developing countries like India; (b) classify and compare different solar cooking technologies, highlighting their advantages and limitations in various scenarios; (c) evaluate the energy efficiency of diverse solar cooking technologies; (d) analyze the impact of solar cookers on communities in developing countries; and (e) identify the challenges and future directions for solar cooker technologies, particularly in solar community kitchens. Our novel findings demonstrate that using solar cooking devices can reduce energy consumption by up to 56% in Indian schools. Moreover, the payback period ranges from 3 to 6 years, contingent on the technology's cost, climatic conditions, and available subsidies. Consequently, significant positive impacts on society, the economy, and the environment are observed when traditional cooking devices are replaced by solar cooking devices. This study provides a unique and thorough analysis, contributing to the growing body of knowledge on sustainable cooking solutions and their potential to transform energy consumption patterns in developing regions.
... Varun [19] reviews the topic with particular emphasis on indoor cooking, stating that it is the need of the hour. Sizable solar cookers produce steam to cook indoors using steam indirectly, typical for temples in India, Indora [20]. There is a need for practical layouts for family-size solar cookers allowing indoor cooking in a conventional kitchen. ...
... This last equation assumes a linear power increase to approach the initial stages of Equation (15). As a result, this equation has an analytic solution given by Equation (20) in non-dimensional terms, assuming as initial condition t = 0 → θ = 0 : ...
... Equations (20) and (22) with data from Equation (21) predict a quite slow and low temperature increase, thus removing the worry of initial times elevated temperatures, owing to the large conductance towards the pot here assumed and its very large heat capacity. If this conductance is ignored, an adiabatic evolution occurs, e.g., an unloaded cooker. ...
The paper offers innovative cooking utensil designs for remote, isolated, and even peri-urban communities at a low price, with high reliability and simple construction. It can alleviate energy poverty and improve food security. This utensil uses only local solar energy directly and allows comfortable indoor cooking. This paper provides the design principles of a solar cooker/frying pan or generic heater, based on a PV panel or a plurality of them, which are directly connected to a plurality of Positive Thermal Coefficient (PTC) resistors to match the power. PTCs are nowadays produced in massive quantities and are widely available at low cost. The proposed device does not require an electronic controller or a battery for its operation. The aim is for family use, although the design can be easily scaled to a larger size or power, maintaining its simplicity. Electric heating inside or attached to the cooking pot, plus the temperature self-limiting effect of PTCs, allows for thermally insulating the cooking pot from its outside using ordinary materials. Insulation enhances energy efficiency during cooking and keeps cooked food warm for a long time. Clean development would receive a significant impulse with its application. A simple mathematical model describes its functioning and states guidelines for adequate design. Its results indicate a successful proof of concept and high efficiency both for water and oil as representatives of cooking.
... Ethiopians' high dependence on biomass energy resources contribute to deforestation, soil erosion, and land degradation. The conventional energy sources are inadequate and quickly becoming depleted with time; on the other hand, rapid increasing population and growing human activities are applying additional pressure with extra demand on the shrinking amount of energy resources [3] [4]. Injera is at bread with a unique taste and texture [4]. ...
... The conventional energy sources are inadequate and quickly becoming depleted with time; on the other hand, rapid increasing population and growing human activities are applying additional pressure with extra demand on the shrinking amount of energy resources [3] [4]. Injera is at bread with a unique taste and texture [4]. It is mainly eaten as the rst-choice food item in Ethiopia and some parts of East Africa. ...
... It is mainly eaten as the rst-choice food item in Ethiopia and some parts of East Africa. Injera baking requires temperatures ranging from 180°C -220°C [4] [5]. ...
Ethiopia is the country which use fossil fuel as main source of energy. About 83% people of the country live in countryside area and use fossil fuel as a source energy for both baking and cooking purpose. Among this 70% of the energy is used for baking injera which needs a high temperature in range of 180–220℃ in a control environment. Thus, substituting it by renewable energy is an admirable solution of the season. The thermal energy is collected using 2𝑚 ² area parabolic dish collector to the heat transfer fluid through spiral copper coil absorber. The experimental setup is manufactured from locally available material. Leakage of fluid was difficult to control during experimental test. Instruments like thermocouple, infrared thermometer and Pyranometer are used in the experimental test. Thus, HTF is heated by parabolic dish collector at the absorber plate and attain up to a temperature of 253℃ and the average day thermal efficiency was around 51.44%.
... Varun [19] reviews the topic with particular emphasis on indoor cooking, stating that it is the need of the hour. Sizable are the solar cookers that produce steam to cook indoors using steam indirectly, typical for temples in India, Indora [20]. There is a need for practical layouts for family-size solar cookers allowing indoor cooking in a conventional kitchen. ...
... This last equation assumes a linear power increase to approach the initial stages of Eq. (15). As a result, this equation has an analytic solution given by Eq. (20) in non-dimensional terms, assuming as initial condition = 0 → = 0: ...
... (21) gives the values for and , according to Eq. (18) and assuming MPP invoking the correct PTC resistance in the initial times. Eq. (20) and (22) with data from Eq. (21) predict a quite slow and low temperature increase, thus removing the worry of initial times elevated temperatures, owing to the large conductance towards the pot here assumed and its very large heat capacity. If this conductance is ignored, an adiabatic evolution occurs, e. g. unloaded cooker. ...
he paper offers an innovative cooking utensil design for remote, isolated, and even peri-urban communities at a low price, with high reliability and simple construction. It can alleviate energy poverty and improve food security. This utensil uses only local solar energy directly and allows comfortable indoor cooking. This paper provides the design principles of a solar cooker/frying pan or generic heater, based on a PV panel or a plurality of them, which are directly connected to a plurality of Positive Thermal Coefficient (PTC) resistors to match the power. PTCs are nowadays produced in massive quantities and are widely available at low cost. The proposed device does not require an electronic controller or a battery for its operation. The aim is for family use, although the design can be easily scaled to a larger size or power, maintaining its simplicity. Electric heating inside or attached to the cooking pot, plus the temperature self-limiting effect of PTCs, allows for thermally insulating the cooking pot from its outside using ordinary materials. Insulation en-hances energy efficiency during cooking and keeps cooked food warm for a long time. Clean development would receive a significant impulse with its application. A simple mathematical model describes its functioning and states guidelines for adequate design. The results indicate a successful proof of concept and high efficiency both for water and oil as representatives of cooking.
... Geometric design considerations and the optical and thermal performance of parabolic troughs are key factors affecting the overall performance of a CSC (Indora and Kandpal, 2018a;Saxena et al., 2011). A common practice to measure the performance of PTSCs using certain performance criteria, including energy and exergy efficiency as well as power output and performance metrics. ...
... Several commonly used performance parameters are required to analyze the performance of CSCs from various manufacturers with different designs and geometries. The test criteria are essential both for licenses and ensuring the quality of solar cookers which are available to users (Indora and Kandpal, 2018a). As depicted in Fig. 13, three main testing standards are defined for solar cookers, which differ significantly in their scope, complexity, and results. ...
... Mullick et al. (Mullick et al., 1991) established the evaluation strategy for evaluating the PDSC's performance for the first time, and presented two metrics of optical efficiency factor (F ′ η o ) and overall heat loss factor (F ′ U L ) for testing a CSC. These characteristics describe a CSC's performance under full load and can be calculated from the heating and cooling test curve (Indora and Kandpal, 2018a). ...
Cooking is known to be one of the most energy-intensive sectors, with an estimated energy consumption of about 30-40% of global energy consumption, with a significant share in developing and underdeveloped countries. Traditional cooking, mainly based on biomass and fossil fuels, is one of the main sources of particulate matter (PM) emissions in household buildings, which is an important risk factor for lung cancer. Due to the negative impact on the environment and the waste of energy by traditional cooking systems, innovative and environmentally friendly cooking technologies are becoming more and more popular. Solar energy, as a renewable resource, is best suited for integration into cookers. Several researchers have studied solar cooking technologies to improve their performance and support their use worldwide. Among various solar cooking technologies, concentrating solar cookers (CSCs) have recently attracted much attention, especially in large-scale cooking, due to their special characteristics of generating high temperatures and significantly reducing cooking time. This study has focused on CSCs including parabolic through solar cookers (PTSCs), parabolic dish solar cookers (PDSCs), and Fresnel lens solar cookers (FLSCs), and describes their various aspects, including their operating principles, design considerations, thermal operation, and test procedures, while recent progress in the research and evolvement of these cookers are comprehensively discussed, taking into account their economic aspects. The major drawback of CSCs remains their high initial cost, especially when thermal energy storage (TES) is integrated. However, overcoming the limitations and realizing the great advantages of CSCs to replace them with other cooking methods can make their use more successful and improve their possibility to become commercial worldwide.
... Solar energy can contribute largely in many applications. Solar cooking being a potential application can help in improving the health of the environment and humans [3]. The rural population using conventional methods for cooking would be the largest beneficiary of solar cooking methods [4]. ...
... Special attention is required for people residing in slums as they require widespread improvement in living standards [25]. Study carried out by Indora et al. [3] reported that the use of solar energy in cooking process is very low as compared to the use LPG in India. Use of LPG has the highest utility in India while the use of electric stove has the lowest utility in India. ...
... Institutional cooking with solar energy: A review Low utilization of available resources Solar systems design and utilization must be decentralized [3] Dissemination of cooking energy alternatives in India-a review Indians use traditional fuel for cooking Renewable energy sources utilization must be maximized [4] Cost-effective solar cookers: A global review Low cost solar cooker must be designed with improved performance [5] State of the art of solar cooking: An overview Lower performance of solar cookers is a big barrier Use of solar cooking can result in high environmental benefits [11] A comprehensive review of solar cooker with sensible and latent heat storage materials ...
Solar energy is best suited substitute energy source owing to its cost-effectiveness and eco-friendly nature. But, the irregular nature of solar energy limits its usage and efficacy in domestic and industrial applications, particularly for water heating. Various research reports demonstrated that increasing convective heat transfer rate and energy storage capacity could increase the thermal output of solar water heating (SWH) systems. Active and passive types are two categories of SWH systems. The aim of the present study is to discuss a crisp review of recent developments made in the field of SWH systems, and focusing on ways used to enhance their thermal performance. The thermal performance improving methods that have received specific attention include geometrical changes to the absorber plate, solar selective coatings, collector tilt angle, fluid flow rates, phase change materials as a thermal energy storage unit, and twisted tape insertion. This study also helps to understand the physical science and mechanism behind the performance enhancement methods used in SWH systems for sustainable energy development.
... Solar energy can contribute largely in many applications. Solar cooking being a potential application can help in improving the health of the environment and humans [3]. The rural population using conventional methods for cooking would be the largest beneficiary of solar cooking methods [4]. ...
... Special attention is required for people residing in slums as they require widespread improvement in living standards [25]. Study carried out by Indora et al. [3] reported that the use of solar energy in cooking process is very low as compared to the use LPG in India. Use of LPG has the highest utility in India while the use of electric stove has the lowest utility in India. ...
... Institutional cooking with solar energy: A review Low utilization of available resources Solar systems design and utilization must be decentralized [3] Dissemination of cooking energy alternatives in India-a review Indians use traditional fuel for cooking Renewable energy sources utilization must be maximized [4] Cost-effective solar cookers: A global review Low cost solar cooker must be designed with improved performance [5] State of the art of solar cooking: An overview Lower performance of solar cookers is a big barrier Use of solar cooking can result in high environmental benefits [11] A comprehensive review of solar cooker with sensible and latent heat storage materials ...
Energy utilization for cooking needs is basic and foremost end use in developing countries. Growing population and depletion in natural resources urges to find the alternate energy sources. Solar energy is available in abundance for free and can be an excellent source for cooking needs. Various types of solar cooking appliances are developed across the world. This study highlights the current scenario of solar energy utilization for cooking in India. The recent developments in solar cooking and its acceptance at ground level are highlighted. The necessity of solar cooking with respect to economy, health and environment and the barriers for its underutilization are also highlighted. The cooking during non-sunshine is the most common barrier while the future with indoor cooking capabilities is most common requirement. The future directions needed to be addressed for improvement in its utility are also presented.
... Its high environmental impact can result in huge decrease in carbon emissions. Its low thermal performance and utilization creates an urgent need to make solar cooking useful technically, economically and socially as suggested in many studies [18,19,[27][28][29]. ...
... A review was carried out on solar based Institutional cooking by Indora et al. [27]. It was suggested that the detailed performance assessment is required so that the economic risks and reliability can be established. ...
... Minor subsides will also popularize it, which will help in resolving the social and environmental issues [150]. Policy benefits by incentivizing measures for manufacturers and installers can also help in establishing this technology [27]. To predict consumer response to any policy decisions can help in promoting solar cooking [151]. ...
The depletion of conventional energy sources and their adverse effects on the environment have fetched the attention of global researchers on the renewable sources of energy. Solar energy is freely and abundantly available and can be effectively utilized in many domestic/industrial applications. Cooking being one of the biggest consumers of energy is an essential component of human lives. Using wood or cow dung as primary source of thermal energy for cooking lead to harmful pollution and unhealthy global environment. The cooking utilizing the solar energy has evolved with many updates over the last few decades.
This review focuses on the recent developments in solar cooking, its components, and heat transfer characteristics. Over the period of time, various geometrical modifications have improved the cooking performance especially in box type solar cooker. Use of reflectors and transparent insulating material has improved the performance significantly. Cooking integrated with other technologies is thermally advantageous and economical. The use of energy storage mediums improved the performance during non-sunshine hours. Use of phase change materials as storage medium has higher impact while, sensible heat storage mediums have proved to be more affordable. Social and economic acceptance must be achieved with better policy implications. The solar cooking technology needs an approach for development to enhance its performance, affordability, and usefulness.
... [21] Solar thermal cooker The findings indicated that the payback period for solar cookers and carbon dioxide emissions was reduced with high utilization. [22] Solar thermal cooker The review indicated that state-of-art concentrated solar cookers are ideal for organizational-level cooking. ...
... These are direct utilization of flat plate collectors, indirect utilization of flat plate collectors, direct utilization of parabolic reflectors, and indirect utilization of parabolic reflectors. Significant review studies on solar thermal cookers were undertaken in the recent past [19,[21][22][23][24]27,29,30,32,[76][77][78][79]. These studies reviewed geometrical designs, thermal energy storage, and nanofluids, techno-economic and social aspects of adopting solar thermal cookers. ...
About 3 billion people use conventional carbon-based fuels such as wood, charcoal, and animal dung for their daily cooking needs. Cooking with biomass causes deforestation and habitat loss, emissions of greenhouse gases, and smoke pollution that affects people’s health and well-being. Hydrogen can play a role in enabling clean and safe cooking by reducing household air pollution and reducing greenhouse gas emissions. This first-of-a-kind review study on cooking with hydrogen assessed existing cooking technologies and hydrogen systems in developing country contexts. Our critical assessment also included the modelling and experimental studies on hydrogen. Renewable hydrogen systems and their adoptability in developing countries were analysed. Finally, we presented a scenario for hydrogen production pathways in developing countries. Our findings indicated that hydrogen is attractive and can be safely used as a cooking fuel. However, radical and disruptive models are necessary to transform the traditional cooking landscape. There is a need to develop global south-based hydrogen models that emphasize adoptability and capture the challenges in developing countries. In addition, the techno-economic assumptions of the models vary significantly, leading to a wide-ranging levelized cost of electricity. This finding underscored the necessity to use comprehensive techno-economic assumptions that can accurately predict hydrogen costs.
... The development and current status of solar cooking technology have been extensively discussed by different authors round the globe (Halacy and Halacy 1978;Saxena et al. 2011;Cuce and Cuce 2013;Arunachala and Kundapur 2020) for latest trends especially some valuable highlights have been reported (Bansal et al. 2013) for a few major concerns between the consumers and policy makers in India to reduce the use of biomass for cooking needs. The said research work focused on different types of cooking fuels (Indora and Kandpal 2018;Herez et al. 2018;Indora and Kandpal 2019;Aramesh et al. 2019;Chatelain et al. 2019;Mendoza et al. 2019;Arunachala and Kundapur 2020;Mekonnen et al. 2020;Mostafaeipour et al. 2021;Khatri et al. 2021;Singh et al. 2021a, b, c, d) of about 9.2 m 2 in the form of a solar steam kitchen to cook some common Indian dishes such as, rice, pulses, and potatoes for up to 2000 people with a diesel backup for cloudy and rainy days (Otte 2014a). Singh et al. (2021a, b, c, d) proposed a large Scheffler dish solar concentrator a solar cooking unit for a 4-5-membered rural family in India. ...
... Consumption of foods with specific combinations of the latter can be significant definers of cultural identity. On a stand in boiling water 100-120 20 The use of solar cooking in institutional kitchens has been restricted by curtailment of the periods for which required cooking surface temperatures are sustained and inconsistent achievement of those temperatures (Otte 2014a); to address the former, Otte (2014b) investigated solar cooking using thermal energy storage (TES) materials to extend hours of operation of solar cookers in communal institutions in Mozambique, and for the latter, the temperatures achieved by concentrating and non-concentrating solar cookers used for institutional cooking have been collated for the case of India by Indora and Kandpal (2018). ...
The successful use of solar energy for cooking requires the systems adopted not only to have technical attributes that conveniently address specific cooking requirements but also are socially and economically acceptable to its end-users. When displacing cooking fuels used in developing countries, solar cooking can lead to (i) improved health in children and women, (ii) less local forest degradation, (iii) less local pollution, and (iv) lower contributions to global greenhouse gas emissions. The diverse range of thermal and photovoltaic solar cooking systems available, or under development, in different regions of the world is discussed in the present work. Particular attention is given to the social, cultural, and economic factors that have limited adoption of solar cookers. Technical developments that address these limitations are shown to only be effective when they facilitate traditional ways of cooking particular foods in and at desired times in specific climates.
... While fuels for cooking are relatively diverse (firewood, charcoal, kerosene, electricity, cow dung, crop residues, wood processing residues), wood-based biomass fuels stand out as the most important. However, in most rural areas of Kenya, the cooking process is done on three stones arranged triangularly to accommodate the pot, on traditional metal charcoal stoves and on the kerosene stoves as shown in Figure 2. [7,8]. ...
... It depends on the sun shine to work and therefore cannot be a stand-alone technology. Solar is a clean source of energy for domestic cooking [7] and institutional cooking [8]. Other researchers have proposed the use of solar induction stoves that are very efficient and option for clean cooking [13]. ...
... Solar concentrators (lenses or reflectors) are used for thermal solar energy conversion as well as for Photo Voltaic applications. Solar concentrators have been used in various forms for direct solar cooking or frying [1][2][3][4]. The thermal energy can be available at off-sun hours if a heat storage is included. ...
Solar concentrators can provide high temperature heat for cooking and frying and the thermal energy can be available at off-sun hours if a heat storage is included. A heat transfer loop is then required, between the absorbers of the concentrators and the heat storage units. A double reflector system has previously been tested for direct illumination of a heat storage, avoiding the heat transfer loop. As solar tracking is still required, a Compound Parabolic Concentrator (CPC) is here evaluated as an alternative. A stationary CPC can capture solar rays for quite wide acceptance angles. Ray tracing is used for assessment of a 3D CPC to illuminate the top part of a small scale heat storage, which is designed for capacity to cook 1-2 kg of beans. The storage has a 20 cm diameter aluminum top plate with conducting fins into a latent heat storage (Solar Salt Nitrate mixture with melting point 220°C). The storage has previously been charged with electric heating elements. The purpose of the ray tracing is to perform a sensitivity analysis on the dimensions of mirror tiles on the CPC surface. The results show that uniform tile sizes up to 15 cm gives quite similar interception ratios (less than 10% changes) compared with the smooth surface. Larger and non-uniform tiles discretized in terms of rings and sectors can give similar results.
... Lower solar concentrations can be applied for PV and higher concentrations for solar power systems. Solar concentrators can be used in many forms for direct solar cooking or frying [4][5][6][7]. If a heat storage is included, the thermal energy can also be available at off-sun hours. ...
A Compound Parabolic Concentrator (CPC) is investigated for capturing and focusing sun rays onto an absorber, for conversion of solar radiation to heat. CPCs are cost-effective as they do not need solar tracking, only requiring tilting of the concentrator at intermediate times during a day. In this study, a 3D CPC with reflecting surfaces is strongly simplified by using only two sets of 4 flat mirrors (upper and lower mirrors) arranged in such a way that they form a quadratic funnel. A cylindrical heat absorber made of aluminum is positioned at the base of the funnel and the system is insulated to reduce the heat losses from the system. The purpose of the heat storage is to accumulate heat at sufficient temperatures for cooking. The idea is that a concentrator can be positioned over the heat storage and be replaced by an insulating cover after the heat storage has been charged. Tests with a CPC system is presented here, with test results in outdoor conditions in Trondheim, Norway during the months of May and June. The heat storage reached temperatures of about 135 °C at solar radiation conditions of 500-700 W/m 2 , higher temperatures are to be expected with improved insulation and at sun conditions closer to equator. Previous separate cooking tests have been successfully demonstrated on a similar cylinder for initial heat storage temperatures of 220 °C. A computational model which was tuned to the 220 °C case showed that even an initial temperature of 140 °C can be sufficient for boiling water although at modest amounts of about 1 l.
... Solar concentrators (lenses or reflectors) are used for thermal solar energy conversion as well as for Photo Voltaic applications. Solar concentrators have been used in various forms for direct solar cooking or frying [1][2][3][4]. The thermal energy can be available at off-sun hours if a heat storage is included. ...
A Compound Parabolic Concentrator (CPC) can be used to capture and focus solar radiations onto an absorber, for conversion of radiation to heat. The benefit of using a CPC is that solar tracking is not needed within the range of acceptance angles for the CPC. The drawback is that the concentration ratios becomes less for point focusing reflectors. As a 3D CPC with reflecting surface is not trivial to construct, the surface has been strongly simplified by using two sets of 4 flat mirrors in a squared channel arrangement. The case considered is a CPC with 1.2 m height, 0.75 m opening and a cylindrical absorber with 0.2 m diameter and 0.25 m height at the bottom of the CPC. The resulting concentration ratio is about 3 for the selected acceptance angle of 15 degrees. The height separating the 4 lower mirrors from the 4 upper mirrors has been optimized using an in-house ray tracer. The interception ratios have been determined from ray tracing simulations for all acceptance angles, varying the separation height of the mirrors. As the concentration ratio is quite small, the interception ratios are quite good, and the optimum dividing position of the mirrors are about 25% of the height of the CPC. Solar concentrators are useful for collecting high temperature thermal energy, and may also be useful for concentrating Photo Voltaic applications. These concentrators are classified based on their concentrating ratios, focal type, tracking systems and their operating temperature, with respect to the type of applications [1]. A Compound Parabolic Concentrator (CPC) is a non-imaging concentrator capable of reflecting incident radiation on an absorber within a wide range of acceptance angles. CPCs can be used for collecting solar heat for a variety of applications [2]. The general principles and geometry of the 2D CPC was described by Winston in 1974 [3]. Later, Rabl and Winston [4] and Winston and Hinterberger [5] provided further explanation and analysis in terms of the optical and thermal performance of the CPC. The CPC aperture diameter is limited and increases with concentration ratio but decreases with acceptance angles. A useful property of a CPC is that the incoming rays can exit the a [m] ]
... This is mostly because native coal is employed to produce energy. However, the increase in solar rooftop installations, solar appliances, as well as LPG-based cooking is anticipated to alter the application of biomass (Indora & Kandpal, 2018). Petroleum, 85% imported, faces challenges due to price volatility as well as restricted access to natural gas. ...
... Since Wolfgang Scheffler's first communications on this technology, his reflector has spread all over the world and especially in India [12,13]. However, scientific studies dealing with its operating principle, its performance, its modeling and its improvement have been quite rare. ...
... Solar thermal energy is regarded as one of the most promising choices for the demands of rural cooking (small scale) and thermal processing (industrial scale). When it comes to using solar energy, solar cooking is an advantageous alternative [12,13]. Meanwhile, in developing countries, both commercial (i.e., LPG, kerosene, electricity, and coal) and non-commercial (firewood, agricultural waste, and cow dung) energy contribute to the majority of the total energy used for cooking [14,15]. ...
... When we examine academic studies on solar cookers, it is evident that an increasing number of studies are being conducted. This field has been particularly scrutinized through various general and specific review studies (Aramesh et al., 2019;Cuce & Cuce, 2013;Farooqui, 2014;Indora & Kandpal, 2018;Lentswe et al., 2021;Sedighi & Zakariapour, 2014;Singh, Sharma, Goyal, et al., 2021;Singh, Sharma, &, Soni, 2021). Some of these studies highlight the energy-intensive nature of cooking, which accounts for a significant portion of global energy consumption and contributes to health risks and environmental pollution, mainly in developing countries. ...
This work presents an extensive and thorough examination of solar cooking systems, offering a comprehensive overview of their design, functionality, and practical implications. Through a comprehensive review of existing literature and technological advancements, the paper highlights the various types of solar cooking methods and their respective benefits. The study delves into the environmental, social, and economic advantages of solar cooking systems, presenting their potential to reduce energy demands and cooking‐related challenges in diverse regions. By synthesizing a wide range of research, this review serves as a valuable resource for researchers, policymakers, and individuals interested in harnessing solar energy for sustainable and efficient cooking solutions. Additionally, this study contributes to the understanding and promotion of solar cooking as a viable and environmentally friendly alternative. It also analyzes why solar cooking systems have not become widespread and reveals the obstacles facing them.
This article is categorized under: Sustainable Energy > Solar Energy
... Solar thermal energy is regarded as one of the most promising choices for the demands of rural cooking (small scale) and thermal processing (industrial scale). When it comes to using solar energy, solar cooking is an advantageous alternative [12,13]. Meanwhile, in developing countries, both commercial (i.e., LPG, kerosene, electricity, and coal) and non-commercial (firewood, agricultural waste, and cow dung) energy contribute to the majority of the total energy used for cooking [14,15]. ...
Solar power is an alternative energy source that can be used for cooking. It is a simple, secure, and useful way to cook food without using conventional fuels that pollute the air. Solar cookers offer various benefits to the user’s health, productivity, and income as well as to the environment. Solar energy is abundant in a tropical country like Indonesia, making it a dependable and sustainable of energy resource. The study’s goal is to analyze the potency of steam produced by a solar cooker that uses a Fresnel lens concentrator. The thermal performance of the Fresnel lens concentrator with a conical receiver on the solar cooker prototype is discussed in this research. In the construction of solar cookers, PMMA (Polymethyl-Methacrylate) Fresnel lenses, single axis trackers, and conical receiver types are used. The research conducts an experimental analysis of the thermal performance of the prototype solar cooker using a Fresnel lens concentrator with a conical receiver. This empirical approach provides valuable data on the efficiency and effectiveness of the solar cooker design. The experiment result shows the cumulative average solar irradiation, the average collection of solar energy per time of Fresnel lens concentrator, and the heat utilized of steam from conical receiver are 709.09 W/m², 456.14 Watt, and 383.88 Watt, respectively. The results of this study suggest that Fresnel lens concentrators are a promising development for indoor solar cookers and therefore provide a pathway for increased utilization of solar cooking technology
... Since Wolfgang Scheffler's first communications on this technology, his reflector has spread all over the world and especially in India [12,13]. However, scientific studies dealing with its operating principle, its performance, its modeling and its improvement have been quite rare. ...
... The total intensity of the heat flux collected by a Scheffler reflector [18] depends on its aperture area, denoted , , and on the direct normal irradiance (DNI), denoted (obtained experimentally with the pyrheliometer). This gives: ...
... Cooking is an essential daily activity that demands a significant amount of energy, approximately 1.7 to 2.7 MJ per person per day (Indora and Kandpal 2018). In this context, solar cooking has emerged as a practical and ecofriendly alternative to conventional fuel-based cooking, especially in remote, rural, and urban regions (Khallaf et al. 2020). ...
This work proposes a novel transparent solar cooker design, and its performance is evaluated using a set of experiments. The cooker is fabricated from transparent and non-transparent, and lightweight material. The study was conducted at the Renewable energy laboratory in India (MNNIT Prayagraj). For thermal performance assessment of Box-type standard solar cooker with an inclined cover (BTSCIC) is compared with a box-type standard solar cooker (BSSC). The area, heat input, and thermal efficiency have all increased significantly. The total absorbing area increases by 32%, total solar radiation by 189%, absorber plate temperature by 19.8%, inner air temperature by 16.5%, pot water temperature by 17.1%, and inner wall average temperature by 58%, as compared to box-type Standard Solar Cooker. The average exergy was 4.2% (BTSCIC) and 2.61% (BSSC), respectively. The cost payback period of BTSCIC was 2.22 years and BSSC 1.5 years.
... The use of solar cookers helps eliminate high concentrations of particulate matter in the cooking ambient, the inhalation of which is harmful to humans [10]. Since the firsts solar cooker was developed in India in 1878 [11], researchers have been trying to improve their efficiency [12], including geometrical features [9,13,14], maximum temperature attained [15,16], energetic cost reduction [17,18], CO 2 emission reduction [19,20], among their many other attributes [9,21,22]. ...
Cooking traditional meals using a solar cooker is often challenging because it may require maintaining temperatures of 63 to 180°C for extended periods. A popular Mesoamerican/Mexican dish, “tamale,” is a vapor-cooked corn dough meal/flour wrapped inside corn husk, which may be prepared in a solar cooker. However, its nutritionally rich variety, “elote tamal” prepared from ground fresh corn kernels of tender corncobs with added sugar, fresh milk, and butter, becomes unpalatable under such solar cooking. The initial slow rise in temperature leads to the fermentation of the dough-milk mix and degrades the product. We show that an auxiliary electric heater boosting the temperature at the initial period in an electric-solar hybrid cooker can overcome this limitation. Furthermore, we found significant differences in the total sugar and titratable acidity in the slow-cooked elote tamal. These differences are associated with the incipient fermentation introduced in the milk-containing dough mix during the slow heating stage in traditional solar cooking. We analyzed and compared the protein, fat, moisture content, ash, total sugars, total fibers, titratable acidity, and color of elote tamales prepared under four different cooking conditions. Milk-based tamales under solar cooking require an additional thermal booster at the initial stage to avoid fermentation and eventual loss of quality of the cooked dish. This research is also relevant to the solar cooking of other milk-based meals.
... The Advanced global responses to the emissions rely on renewable energy projects, which are gradually replacing non-renewable energy, for instance, renewables (solar, wind, geothermal, and others) are being used for cooking, green transportation, manufacturing, and others [8][9][10][11][12][13]. Some literature argued that the higher dependence on traditional energy, higher carbon emissions releases, and the situation changes within development categories [14][15][16][17][18]. Like other renewables, Wind energy is at a good stage in developed and developing countries to replace fossil fuel and coal combustion as well as accelerate the advanced CO 2 reduction Agenda. ...
... Recently, in the food and agriculture industry, solar energy has been used as energy supply to lower the costs, to dry foods (solar dryer) or applied to waste transformations [2][3][4]. The use of solar cookers was initially developed to help the population during calamities or to diminish the people's need of wood or charcoal for water sterilization and food preparation [5,6]. Recently, the new ecological sensitivity of modern society has led some people to extend the use of solar cookers in natural environments, such as camping areas or outdoor excursions. ...
The use of efficient solar ovens can be a way for progressing ecofriendly technologies in the field of food preparation. In most performing direct solar ovens, the sun rays reach the foods directly, therefore, it becomes essential to check whether, in these conditions, foods can retain theirnutraceutical properties (antioxidants, vitamins and carotenoids). In the present research work, to investigate this issue, several foods (vegetables, meats, and a fish sample) were analyzed before and after cooking (traditional oven, solar oven, and solar oven with a UV filter). The content of lipophilic vitamins and carotenoids (analyzed via HPLC-MS) and the variation of total phenolic content (TPC), and antioxidant capacity (via Folin–Ciocalteu and DPPH assays) have evidenced that cooking with the direct solar oven allows to preserve some nutrients (i.e., tocopherols) and, sometimes, to enhance nutraceutical properties of vegetables (for example, solar oven-cooked eggplants showed 38% higher TPC compared to electric oven cooked sample) and meats. The specific isomerization of all-trans-β-carotene to 9-cis was also detected. The use of a UV filter is advisable to avoid UV drawbacks (for instance, a significant carotenoid degradation) without losing the beneficial effects of the other radiations.
... Panel solar cookers are not suitable for frying. On the other hand, they can bake breads, cakes, and other baked goods with virtually no carbon footprint (Indora, 2018). ...
Brazil is a tropical country which has an average of 250 sunny days per year. Unfortunately, very little solar energy is used for both heating water and for food cooking with solar cookers. Traditional cooking process demands fuel consumption while solar cooking takes advantage of the abundant, free solar energy. This article proposes the use of affordable panel solar cookers, with a sustainable design, based on waste materials, such as cardboard and potato chips metallized plastic bags as alternative materials to commercial reflective aluminum foil or reflective plastic films. Our work is an example of the feasibility of simple, fast and low-cost solar cooking apparatus and techniques dissemination among underprivileged communities.Keywords: Solar Energy; Affordable Solar Cookers; Sustainability, Waste Materials Oficina de Fogões Solares para Comunidades de Baixa Renda: Uma Iniciativa Socioambiental.ResumoO Brasil é um país tropical que tem em média 250 dias de sol por ano. Infelizmente, muito pouca energia solar é usada para aquecer água e para cozinhar alimentos com fogões solares. O processo de cozimento tradicional exige consumo de combustível, enquanto o cozimento solar aproveita a abundante energia solar gratuita. Este artigo propõe a utilização de fogões solares de painel de baixo custo, com design sustentável, a partir de resíduos, como sacolas plásticas metalizadas de papelão e batata frita, como materiais alternativos às folhas de alumínio reflexivas comerciais ou filmes plásticos reflexivos. Nosso trabalho é um exemplo da viabilidade da disseminação de aparelhos e técnicas de cozimento solar simples, rápido e de baixo custo entre comunidades carentes.Palavras-chave: Energia Solar; Fogões Solares Acessíveis; Sustentabilidade; Resíduos.
... The major application of Scheffler collectors is institutional/community cooking, wherein multiple collectors are connected through a pumping network to generate steam. Indora and Kandpal [26] have reviewed different institutional cooking systems installed in India. Another class of review articles is region-specific, wherein solar cookers suitable for/ being used in the specific region/country are detailed [27][28][29][30][31][32]. ...
A significant amount of domestic energy consumption is for cooking in the majority of the countries. However, open fire cooking using wood and charcoal releases harmful climate-warming emissions. Thus, developing a clean cooking technology is the need of the hour, which includes electric and solar cookers. In most cases, the former technique involves converting thermal energy to high-grade electrical energy and converting it back to thermal energy is energy-splurging, if not criminal wastage of energy. The latter option uses either non-concentrated or concentrated solar thermal energy directly for cooking and, therefore, is more efficient (as high as optical collection efficiency) besides helping reverse global warming.
Low-cost solar cookers for outdoor cooking have been available for a long time. However, it has low social acceptance due to the inconvenience of cooking outdoors rather than in the kitchen and the inability to cook during off-sunshine hours. Hence, in line with the current need, this review explores numerous designs of solar cookers intended for indoor usage, which includes thermosyphon systems, Scheffler cookers, pumped systems, and other innovative designs.
Most of the designs reviewed are operated in a shaded area rather than a true indoor system. Although pumped systems solve this issue, the auxiliary power requirement and reliability are questionable. Hence, a few designs are handpicked for their novelty and ease of indoor cooking. Solar chulha, being one of them, has great prospects as the design involves a sustainable mechanism for round-the-clock indoor solar cooking.
... India, China and several African countries have used solar cookers to replace firewood, reducing the emission of pollutants and desertification caused by the indiscriminate use of this energy source that is still massively used by poorer countries, causing ecological and environmental imbalance. (Neto et al., 2021), (Ruivo, n.d.), (Indora and Kandpal, 2018), (Saxena and Agarwal, 2018), (Singh and Sethi, 2018), (Zafar et al., 2019) and (Aramesh et al., 2019). Such studies point to the slow and gradual need for the practice of solar cooking, since the culture of cooking using firewood is already very consolidated by the communities. ...
... Parabolic trough collectors (PTCs) find applications in cooking using solar energy and have potential benefits in elimination of green house gases (GHGs) [1][2][3][4]. Thermal energy storage (TES) systems when integrated with such PTCs [5][6][7][8] can be a potential technology for steam cooking over 24 h. Phase change materials (PCMs) can serve as potential TES media for this application owing to their latent heat storage [9]. ...
Low thermal conductivity of organic phase change materials (PCMs) for thermal
energy storage systems induces the necessity to apply suitable heat transfer
enhancement techniques for these materials. The purpose of this study was to
improve thermal conductivity of a PCM erythritol by using sodium chloride as
an additive, such that the material can be applied for steam cooking systems
when integrated with solar parabolic trough collectors. In this study,
erythritol-NaCl composites were synthesized by using the melting method, and
the key physicochemical properties of the composites were estimated by using
differential scanning calorimetry (DSC) coupled with thermo-gravimetric
analysis (TGA). The observations indicate that there has been a significant
improvement in the thermal conductivity of erythritol supplemented with
NaCl. Further, thermal behaviour of the material indicates that it is
suitable for steam cooking applications. Furthermore, mathematical models
based on the experimental observations can be potentially utilized for
further studies of erythritol-NaCl composites.
... Kandpal [52] 2018 ...
Biomass and fossil fuels are mostly used in rural areas of developing countries for cooking. These energy resources have negative impacts on the environment and human health mainly due to deforestation and greenhouse gas emissions. A cleaner and environmentally-friendly form of cooking is solar cooking using the sun's energy. Parabolic solar cookers perform better than other solar cookers such as box solar cookers since higher temperatures are achieved in a shorter duration. These higher temperatures allow most types of cooking processes such as; boiling, frying, roasting, and baking to be possible. The major problem with most conventional solar cookers is that cooking is not possible during off-sunshine periods. Integrating solar cookers with thermal energy storage (TES) makes cooking during off-sunshine periods possible. This paper presents a comprehensive review of parabolic solar cookers with TES which is a sustainable cooking solution for developing countries. Previous work on both parabolic trough and parabolic dish solar cookers with TES is presented. Solar cookers with storage are classified according to the two main types of TES technologies which are; sensible heat thermal energy storage (SHTES) and latent heat thermal energy storage (LHTES). The main conclusions of the review are that; parabolic dish solar cookers with TES are more common than parabolic trough cookers, more studies have been done using latent heat storage as compared to sensible heat storage, limited modelling work has been presented, most of the parabolic cookers used aluminum sheets as the reflecting material, large scale experimental studies are limited and fewer studies tackled the techno-economic and socio-economic aspects. The review also highlights research gaps on parabolic solar cookers with TES in terms of the modelling, combined TES (sensible and latent heat), different reflector materials, large-scale experimental setups, and techno-economic and socio-economic analyses. Other important aspects to consider for parabolic solar cookers with TES include; the choice of sensible or latent heat storage materials, environmental impact, types of food to be cooked, and social acceptance.
... The utilization of solar power to replace petroleum gas was to cook with solar cookers. Solar cookers are the device that uses sunlight as fuel to cook the meal [4]. Solar cookers use free energy from the sun, so it's cheaper and cleaner because it didn't release carbon dioxide [5]. ...
The amount of energy resources from fossil fuels continue to decrease, these lead to high demand for renewable energy. One of the biggest energy resources in our nature is solar power. A solar cooker is a device that uses solar power to cook a meal. The performance and temperature of solar cookers depend on the material we use in the device. One of the most important components in solar cooking is reflector because solar cookers use a mirrored reflector to collect and transfer sun rays into the cooking pot to increase the temperature inside the pot. This paper compares two different materials as a reflector in solar cookers. The first reflector is aluminum foil tape, these materials are very cheap, light, easy to use so it could be applied in many designs. The Second reflector used was zincalume steel, it has the highest reflector among other thin steel available in the market. The design of panel reflector from aluminum foil tape was 4 rectangular and the design of zincalume steel reflector similar to cone. The performance of two different reflectors has been analyzed in Solar cookers used to boil 500ml water for 120 minutes. Water temperature from the first and the second reflector showed a similar result. It showed that reflector made from aluminum foil tape and zincalume steel has similar reflectivity.
... Energy for cooking is the main energy consumption for households [1]. Most people used electricity and petroleum gas as cooking fuel, in a developed country they used firewood or biomass [2]. ...
People all over the world always cooked every day, the fuel they used neither biomass, fossil fuels or firewood. All of these fuels had several problems, it can cause global warming and some of them nearly extinct. Solar cookers can be used to solve this problem. These cookers use solar radiation as fuel, so it won’t be extinct. The device has been used in some developed country and successfully reduce pollution at a low cost. A minus point of solar cookers is, it was consumed a longer time to cook which caused many people to still prefer conventional cookers. This research tried to reduce cooking time in solar cooker by adding a convex lens as a light collector. The design of solar cooker used a common rectangular with a size 45 × 20 × 12 cm and three reflector panels attached. Various components like reflector, insulation and cover lid have been analyzed to created solar cookers with lower cost and better performance. Solar cooker builds from wood and the inner part is coated with black styrofoam for storage heat. Mirror and aluminum seal has been used as a reflector and the result showed mirror had similar performance with aluminum seal. Convex lens put directly on top of cookers lid, the pot with convex lens reach 5-8° C temperature higher than the one without it.
... It is reported that the installed setup of 12 dishes of Arun (each having 169 sq.m of projected area) at Mahanand dairy project can save an equivalent of about 1500 barrels of oil per day. The steam generated by the ARUN® dishes is used in thermal requirements of a variety of operations viz.: pasteurization, condensing of milk, can washing, cleaning in place, crate washing, sterilization, etc. (Indora andKandpal, 2018, Energitica, 2019). ...
Abstract:
Community solar cookers (CSCs) hold significant promise for addressing energy poverty and promoting sustainable development. However, existing methods for evaluating CSCs performance are primarily reported in low-temperature applications. This study addresses this gap by proposing a Cooker Opto-Thermal Ratio (COR) based performance evaluation approach for CSCs operating at intermediate temperatures (120-300 °C) for the first time. The big parabolic dish concentrating solar collector (3.801 m2 aperture area) acts as a CSC, which holds a cooking load (test fluid) of ∼ 13 kg in a cooking pot.
Results depict that the average COR value for the CSC is 0.163, and the reference cooking time of the CSC varies between 35-46 minutes. Also, the highest achievable fluid temperature shows variation between 167-180 °C. The capital cost of CSC is $ 396, and the LCCM is 0.039 USD/Ml, which is competitive with the levelized cost of LPG-based cooked meals. While the study provides valuable insights, it is limited to a single CSC design. Future research should investigate the applicability of COR across various CSC geometries and configurations. This research establishes a framework for accurate performance assessment and facilitates the development of more effective CSCs for clean and sustainable cooking in decentralized communities.
A systematic approach and methodology for financial appraisal of the Scheffler dish solar cooker has been presented in this study. An approach is applied to meet the useful cooking energy demand at a location with a high availability of DNI by a Scheffler type of 16 m² area and the effective aperture area of 11.65 m², weight of 400 kg, an efficiency of 40% with 980 (kg/year/ m²) steam output at 120 °C. For this analysis, 5 Scheffler dish solar cookers have been selected for preparing boiling type food like rice and pulses for 750 beneficiaries at Vivekananda Global University, Jaipur, Rajasthan, India. Presently, the cooking energy demand is fulfilled by conventional method such as LPG fuel and it makes the system costly and hazardous in certain cases. By using solar cooking at the location, it is analyzed that the cost is significantly reduced along with other socio parameters also which shows the novelty of this study. The serving time of food is taken from 12:30 to 1:30 pm. The total number of cooked rice and pulses is calculated as 586.5 and 838.38 in 325 operating days. The performance of the Scheffler dish solar cooker is found to be higher in terms of the total number of meals cooked per annum by each cooker is 1424, and the saving of LPG per annum by the Scheffler dish cooker is estimated as 679 kg per cooker. This also contributes to improving the health of women, reducing child mortality rate and CO2 emissions. The net monetary benefit is estimated at INR 30,179.9. The payback and discounted payback periods are estimated as 5.3 years and 7.9 years, respectively. The estimated positive value of net present worth also clearly indicates the profitable application of solar cooker.
Several issues such as sustainability, CO 2 footprint, and energy supply security which primarily resulted from fossil fuel emissions have become the main concerns for analysts and policymakers worldwide. Therefore, to meet the goals of sustainable energy as well as the switch to a net-zero and low-carbon economy, energy systems must be diversified by increasing the implementation of renewable and clean sources of energy. This paper focused on the deep analysis of the key role of bioenergy, geothermal, solar, hydropower or hydrogen, ocean, and wind (BIGSHOW) renewable energy in producing clean energy aiming to attain the sustainable net-zero norms and climate change mitigation. Furthermore, AI technology and its applicability were also introduced to enhance the management efficiency of BIGSHOW in energy-use strategies. More importantly, barriers and bottlenecks of deploying BIGSHOW projects and applications were comprehensively analyzed. Finally, policy implications and vital solutions were thoroughly presented aiming to increase the penetration of BIGSHOW to the energy system. In short, this work could be strong and persuasive evidence for speeding up the shifting progress of a precarious fossil fuel-based economy to a sustainable low-carbon one, in which BIGSHOW has been known as the core role.
A Scheffler reflector is a device which converts the Sun's radiation into energy. The receiver is placed at a distance from it to absorb the focused sunlight on it. The way to enhance the performance of a Scheffler reflector is to change the coating material. For a wide range of wavelengths different materials can be used for these coatings, and it is shown that by using different materials the heating output of Scheffler dishes can be enhanced. We have studied the performance analysis of reflectivity of various materials which can be used in Scheffler reflectors like aluminum and glass as well as silver and stainless steel are all great materials with high reflectance. As Scheffler reflector plays a significant part in renewable energy, it can be used in a variety of ways by modifying the material used to cover the reflector dish.
Practical utility of solar cookers is on rise nowadays. However, due to certain technological challenges this is not catching very fast. Present review paper encompasses studies and future possibilities for solar box cooker research. Various aspects like thermal performance param-eters, various phases of designs improvements, social acceptability issues and computational methods of analysis have been discussed in relation to Solar box cookers so that technical difficulties may be minimized. This paper discusses about introduction to solar box cookers, advantages, disadvantages, various practical considerations that are key factors for any SBC. Further, there is a handsome discussion on the various computational techniques like Com-putational fluid dynamics, Artificial intelligence techniques, IoT etc. Introduction, review of applications till date, and future possibilities related to research using application of these computational techniques have been presented. Emphasis has been given to future possibili-ties for solar box cookers development so that it could be a well-accepted future technology.
Solar energy is one of the hopes for the future of energy requirements. Solar cookers are in use and continuously area of research to improve their usage and popularity. The need for solar cookers become intense in present days because of the continuous shortage of conventional resources and hike in Liquid petroleum gas (LPG) cylinder prices. From the literature survey, it is observed that the solar cooker is more reliable with the use of energy storage systems. This paper presents the analysis of the solar cookers with an energy storage system. This study has been performed by using a latent energy storage system with two-phase change materials which are paraffin wax and HDPE. As a measurement of cooker performance, cooking time has been observed from an experiment. Also, cooking time has been estimated by forming the regression model using Minitab software, and then the model has been validated. This equation helps in the development of a solar cooker for any requirement and for any conditions.KeywordsEnergy storage systemPCMSolar cookingRegression analysis
As typical absorbing solar energy collectors, direct absorption solar collectors (DASCs) have shown great potentials in solar energy utilization. However, due to the instability and discontinuities of solar energy, it is difficult for the heat source output sustainably. Fabrication of direct solar energy storage system is appealing, which can combine the DASCs system and the phase change materials (PCMs) storage system in one unit. In our current work, using biomass-derived porous carbons (PC) as solar energy absorbance materials and adipic acid (AA) as PCMs in a direct solar storage system, integrations of solar energy collection, photo-thermal conversion and long-term energy storage have been achieved. The photothermal conversion efficiency of AA+7 wt% PC is as high as 93.83%. The thermal conductivity of the AA+7 wt% PC is 1.18 W/(m·K), which is 149% higher than pure AA (0.45 W/(m·K)). The PC-CPCMs have the advantages of no subcooling, and the energy storage density can reach 195.05 J/g. The environmental benign and cheap biomass porous carbons based composite PCMs encapsulated in direct solar energy storage systems pave a new avenue for high utilization of solar energy. It can meet thermal energy demands independent of weather conditions and time effects.
A new eutectic chloride molten salt, MgCl2-KCl-NaCl (wt.% 45.98-38.91-15.11), has been recognized as one of the most promising high-temperature heat-transfer fluids (HTF) for both heat transfer and thermal storage for the 3rd Generation concentrated solar thermal power (CSP) systems. For the first time, some essential thermophysical properties of this eutectic chloride molten salt needed for basic heat transfer and energy storage analysis in the application of concentrating solar power systems have been experimentally tested and provided as functions of temperature in the range from 450 °C to 700 °C. The studied properties include heat capacity, melting point, heat of fusion, viscosity, vapor pressure, density, and thermal conductivity. The property equations provide essential database for engineers to use to calculate convective heat transfer in concentrated solar receivers, heat exchangers, and thermal storage for concentrated solar power plants.
The solar energy is a source of energy that is abundant in Malaysia and can be easily harvested. However, because of the rotation of the Earth about its axis, it is impossible to harvest the solar energy to the maximum capacity if the solar thermal collector is placed fix to a certain angle. In this research, a solar thermal dish with single axis solar tracking mechanism that will rotate the dish according to the position of the sun in the sky is designed and developed, so that more solar rays can be reflected to a focal point and solar thermal energy can be harvested from the focal point. Data were collected for different weather conditions and performance of the solar thermal collector with a solar tracker were studied and compared with stationary solar thermal collector.
The objective of this research was to design a low cost parabolic solar dish concentrator with small-to moderate size for direct electricity generation. Such model can be installed in rural areas which are not connected to governmental grid. Three diameters of the dish; 5, 10 and 20 m are investigated and the focal point to dish diameter ratio is set to be 0.3 in all studied cases. Special attention is given to the selection of the appropriate dimensions of the reflecting surfaces to be cut from the available sheets in the market aiming to reduce both cutting cost and sheets cost. The dimensions of the ribs and rings which support the reflecting surface are optimized in order to minimize the entire weight of the dish while providing the minimum possible total deflection and stresses in the beams. The study applies full stress analysis of the frame of the dish using Autodesk Inventor. The study recommends to use landscape orientation for the reflective facets and increase the ribs angle and the distance between the connecting rings. The methodology presented is robust and can be extended to larger dish diameters.
Parabolic concentrator is used to utilize the solar energy for heating purpose. Thermal tests are performed on concentrator at different time periods and at different masses to find the variation in the optical efficiency and heat loss factor. The results verified by graphical test can be used to design the concentrator for the desired output. It was found that the system gave almost the same values of optical efficiency, for the various masses of water on different days. The value of optical efficiency factor increases slightly by reducing the mass of water. The value of optical efficiency for the parabolic concentrator is obtained as 35%.
SK-14 solar concentrator is a widely used and popular domestic solar cooker in parabolic dish cooker category. If the bowl of solar concentrator is fabricated then concentrators become bulky and transportability is a problem. If the bowl is not fabricated and only reflector sheets are stitched together with screws and bolts then transportability improves but bowl is weak and gets damaged even with high wind or strike of a ball or a stone. Author1 developed a new geometry of solar concentrators with square or rectangular shape and PRINCE-15 is one such concentrator which matches aperture area of SK-14. This new design permits framed bowl structure with excellent transportability. A comparative testing was done with these two solar concentrators of same aperture area but different geometries. Standard test protocols were used and both the concentrators were tested simultaneously so as to nullify the effect of wind and any error because of radiation measurement. Results show that PRINCE-15 not only has better transportability but also higher efficiency.
There are a few standards reported in the literature for testing and evaluation of thermal performance of solar concentrators based on sensible heating of working fluid. The preceding standard measures only the cooking efficiency and cooking capacity. Apart from thermal efficiency, there is an imperative need for other important parameters of the solar concentrators such as its stagnation temperature, cooking capacity, cost per watts delivered, weight of the cooker, ease of handling and aesthetics. The characterization of a concentrator at its operating temperature settles appropriate size and type of concentrator for any thermal application. The performance test is conducted at Chandwad (20.3292°N, 74.2444°E), Maharashtra and the proposed protocol aims for evaluation of thermal performance of solar cooking system and standardization of reporting the test results so that anyone can easily recognize and use it.
Malaysia is a 'newly-industrialized' country that relies heavily on its exports of oil and is a major producer of palm oil and rubber. Due to favorable geographical attributes, renewable resources such as hydroelectric, solar and biomass provides attractive alternatives to dependence on fossil fuels. Fuel diversification policies were introduced in 1999 to promote the use of renewable energy, particularly in electricity generation. Diversification of energy resources are one of the main pillars in the new Malaysia plan. Other than hydroelectric and solar energy, biomass from palm oil and other agricultural practices including fruit crops can be utilized to produce energy and renewable resources. Although existing policies point towards integration of sustainable energy resources, a more aggressive approach is needed to substantially offset fossil-fuel consumption.
Solar concentrators for small scale applications typically make use of parabolic dishes or approximations thereof. Fully three dimensional parabolic dishes are expensive to manufacture whilst approximations to these dishes, i.e. the compound parabolic concentrator, will either compromise the ability of the system to obtain a point focus or require additional supporting structures to hold the multiple mirror facets in place. This paper will present the novel geometry of a system of mirrors that produces a point focus whilst using two single curvature surfaces. The focusing abilities and tolerances to tracking errors of this novel system will be presented in comparison to parabolic dishes.
One of the critical aspects characterizing the behavior of the solar mirrors is their specularity [1], which characterizes its capability to focus all the reflected light into the solar collector. Specularity is highly dependent on the roughness of the substrate used to manufacture the mirror, so the roughness of the substrate is definitely a key point to develop products of the highest optical quality with potential to substitute the conventional floated-glass mirrors.
Durability analysis of solar mirrors is attracting attention from Concentrating Solar Power (CSP) developers because guaranties of a suitable optical behavior during the whole service life time are required. To give realistic life time estimations in affordable time, research institutes are investing a lot of effort in developing appropriate accelerated aging tests. In this paper, an extensive test campaign of accelerated aging tests has been performed with silvered-glass mirrors from several manufacturers. Three commercial outdoor-proven products, a not outdoor-proven mirror prototype and two mirrors which showed degradation after only three years of outdoor operation in Spain and Australia have been tested. The accelerated agingtests were conducted for an extended period of time in order to determine the testing time at which the two mirror materials that showed degradation outdoors start to fail under the accelerated conditions. The degradation of the outdoor exposed mirrors is analyzed microscopically and compared to the degradation appearing under accelerated aging. The presented data on accelerated testing represents useful information for standardization of durability testing of solar mirrors.
An attempt has been made in this work to develop a simple yet efficient sun tracking mechanism (SSTM) using smart shape memory alloy (SMA). This mechanism is directly activated by the sun dispensing with the requirement of an additional external source to power it. The SMA element incorporated in the SSTM device performs the dual functions of sensing and actuating in such a way as to position the solar receptor tilted appropriately to face the sun directly at all times during the day. The mechanism has been designed such that the thermal stimulus needed to activate the SMA element is provided by the concentration and direct focusing of the incident sun rays on to the SMA element. This paper presents, in detail, the design and construction adopted to develop the functional model that was fabricated and tested for performance.
In this study, three different types of solar cookers namely; box-type, panel-type and parabolic solar cooker were designed and constructed using locally available materials. The main objective of the study was to investigate the thermal performance of the constructed solar cookers. The standard procedure for testing solar cookers was adopted to test the thermal performance of the constructed solar cookers. Several tests were conducted on the constructed cookers under Zalingei (Sudan) prevailing weather conditions during March 2011. In addition, a questionnaire was designed to evaluate the dissemination possibility of the constructed solar cookers in the study area which consisted of 50 respondents (males and females). Results of thermal performance showed that, the parabolic solar cooker attained a maximum temperature of 86.5ºC on average basis and was the best followed by the box-type solar cooker 52.36 ºC and finally the panel-type 43.5 ºC. Also the results of the solar cookers, efficiency for the parabolic cooker, box-type and panel-type were found to be 31.53%, 77.4% and 67.4%, respectively. Finally the results of questionnaire indicated that 74% believe that solar cookers were economically feasible and could protect the environment.
Financial appraisal of two solar cookers (SK-23 and Scheffler dish) that may be used for institutional/community cooking is presented. For each solar cooker type, three different categories in terms of performance and cost as prevailing in the market have been considered. Annual numbers of solar cooked meals and consequently the values of several measures of financial performance are estimated for three locations in India with varying climatic conditions. As per the estimates obtained in this study a SK-23 solar cooker can cook from 39% to 60% of the meals during the year while, the corresponding range for Scheffler dish based solar cooker is from 59% to 85% at these locations. The discounted payback for SK-23 varies 6.2–9.2 years while the same for Scheffler dish varies from 9.5 to 11.7 years. The financial attractiveness of SK-23 is adversely affected by its poor performance in high wind, while the relatively higher capital cost of the Scheffler direct cooker apparently makes it financially unattractive. Thus, there is an urgent need to encourage research and development on solar cookers to reduce their cost and also to improve performance.
In this work, a review on solar cookers is presented. This review includes principle and classification, parameters influencing the performance of a solar cooker, and energy and exergy analysis related to solar cooker systems. Moreover, an economic study is performed for different scenarios in Lebanon (home, hotel, restaurant and snack) and for several categories of solar cookers (solar box cooker, solar panel cooker, parabolic solar cooker and evacuated tube solar cooker with thermal storage). The main idea of the economic study is to estimate the payback period in function of percentage of time Pr where solar cooker is utilized, for each solar cooker and in each scenario. It was obtained that the higher dependence on solar cooker decreases payback period. Besides, environmental analysis is implemented to compute the amount of reduction in carbon dioxide emissions in the different scenarios as percentage of time where solar cooker is used varies. It was shown that the reduction in amount of carbon dioxide raised from 6.05 to 60.55 kg/month, 605.52 to 6055.2 kg/month, 399.64 to 3996.43 kg/month and from 90.82 to 908.28 kg/month in home, restaurant, hotel and snack respectively when Pr increased from 0.1 to 1. Hence, utilizing a solar cooker diminishes carbon dioxide emissions in all scenarios where Pr has direct relationship with minimization of carbon dioxide emissions.
Solar cooking is considered one of the most attractive ways to utilize solar energy. Therefore, in this work a high concentration ratio (11.12) solar box cooker prototype was manufactured and tested. The cooker has a cooking chamber with a glass cover on the top and is composed by two rows of booster mirrors. The prototype allows both an azimuthal and zenithal manual orientation. A test bench used to characterize the cooker performance is then described. Experimental tests without load were carried out to evaluate the maximum cooker temperature. Tests with load, conducted using aluminum vessels containing a certain amount of water, were accomplished with both standard vessels and black ones, and with one or two vessels. Additional tests were carried out with peanut oil. Using this fluid, temperatures higher than the water ones were achieved (>200 °C). Results show that the cooker is able to cook at high temperature with good optical efficiency and thermal insulation.
An assessment of the financial feasibility of using solar pre-heated water in institutional cooking applications in India is made. Use of solar heated water to reduce fuel requirement for institutional cooking applications is being proposed as the existing solar cooking options have not yet been acceptable. For example, hot water delivered by solar water heating systems (SWHS) installed in government schools can be used for cooking Mid Day Meal (MDM) to be served to school children. As an illustrative example, for 35 locations in India, spread all over the country, annual amount of useful thermal energy likely to be delivered by SWHS have been estimated using System Advisor Model (SAM) and the same has been used to estimate the annual fuel savings. Financial feasibility of the proposed approach has been assessed in terms of payback period, net present value, benefit to cost ratio and the internal rate of return of the incremental investment on SWHS. The annual amount of LPG saved varies in the range of 111 to 178 kg for a system for cooking of 100 MDM per day translating to annual LPG saving of 13200 – 21360 tonnes for about 120 million MDM beneficiary students in India. The payback period at all locations is found to be much lower than useful life of SWHS. Even with the consideration of the fact that the solar heated water would not be used on school holidays, the proposed approach of using solar pre-heated water for cooking appears to be financially attractive for all locations considered in the study.
This article serves as an update to the manuscript with the same title published back in 2010. Since then, Malaysia has seen some major changes in its energy and electricity generation scene. The country is now in the 11th Malaysian Plan (11MP) and its final thrust towards the high-income status targeted by 2020. Keeping to the scope in addressing the country's energy security and sustainability through non-renewable and renewable energy (RE), this article shall update on the existing and new significant energy-related events that have taken place and how they have affected the energy landscape of the country. In addition to that, the important role of the various energy efficiency (EE) and conservation practices set in place to ensure sustainable demand growth is also highlighted. The removal of fuel subsidy by the Malaysian government in 2014, although as unpopular as it may seem, was necessary as part of its energy reform to implement a more common energy regulatory framework involving all relevant agencies to safeguard a secured and sustainable energy future is also covered here. Lastly, latest development and issues surrounding the nuclear dream that the government is currently pursuing will also be discussed.
Despite its vast natural resources, African is facing serious challenges in sustainable development in an energy sector, if addressed with dispatch could not only check its indispensable needs, but also mitigate some global phenomenon at stake, such as desertification, environmental degradation and green house emission. This paper reviews the prospects of four major renewable energy sources-hydro, solar, wind and biomass- for each of the three leading countries in Africa namely South Africa, Egypt and Nigeria. Based on literature survey of energy efficiency, all the three countries encourage energy efficiency in varying degrees. In the course of this review, several national energy policy frameworks of these countries were looked into, especially on how African countries could overcome the persistent energy crisis in the continent by utilizing the naturally gifted renewable energy sources. This could only be achievable if proper technology, awareness and skills for harnessing the resources are provided. Also lingering energy challenges such as energy efficiency measures, needs for grid extension, energy storage technology and seasonal variation were carefully highlighted.
Ghana has been facing perennial power rationing over the years due to fuel supply challenges. The country's energy system is likely to suffer additional strain from rising energy demand fueled by population growth, rapid urbanization and economic development. Fortunately, there are enormous renewable energy resources which can provide sustainable electrification as backbone to socioeconomic development while curbing global warming. Ghana's energy strategy targets 100% access to electricity and 10% share of sustainable power in national generation mix by 2020. Despite the existence of numerous policies and a “Renewable Energy Act”, current contribution of non-conventional renewable energy to electricity generation is less than 1%. The right mix of policies to address the unique domestic conditions and achieve its specific development goals remains insufficient. This study reviews the regulatory framework, financing incentives and other provisions of Ghana´s Renewable Energy Act. It critically examines the policy´s strengths, weaknesses, opportunities and treats based on comparative analysis and lessons drawn from failed and successful implementation of similar policies around the world. The study also assesses the impact of policy on project development. It was found that the performance of Ghana´s renewable energy policy on grid connected electricity has been poor compared to its target. The fundamental reasons for this unsatisfactory performance may be attributed to partial implementation of policies, lack of market driven support schemes, lack of pricing policy framework, weak grid network, limited access to funds and inconsistencies in renewable energy development strategies. This study proposes the following countermeasures; I.Ghana should comprehensively harmonize renewable energy regulatory and fiscal policies with domestic electricity pricing regime, II.market driven support schemes should be prioritized for cost effectiveness and minimum governmental influence. These reforms can help eliminate some of the major barriers to sustainable electrification in Ghana while the lessons provide a learning curve for other African countries.
A Scheffler collector is a fixed focus solar radiation concentrator. It has capacity to increase the temperature of the receiver up to 200 °C. It is being widely used in the various applications such cooking food, generation of power in the solar thermal power plant and etc. This communication presents a complete review of the Scheffler collector. The first part reviews a complete designing of a Scheffler collector with respect to the equinox by selecting a specific lateral part of a paraboloid. The next part compares the energy and exergy analysis of the Scheffler collector followed by the various applications of Scheffler collector and its recent developments.
Parabolic dish technology, for concentrating solar power (CSP) applications, has been continuously modified and improved since the pioneering work in the 1970s. Best practice dishes now have features such as lightweight structure, balanced design, high-quality, low-cost mirror panels, and can be deployed rapidly with little in-field labour. This review focuses on the evolution of dish design, by examining features such as mode of tracking, structure and mirror design, for a wide selection of CSP dish examples. The review includes a brief summary of power generation options – both on-dish and central plant – as well as a discussion about options for storage and hybridisation.
Solar energy which is incident on the earth surface is mostly in diffused form. Hence, ordinary solar water heating technology is able to supply only low-temperature hot water (40–70 °C), primarily used for residential water and space heating. This range of temperature can hardly meet specific energy demand such as food processes, dairy processes and other industrial process heat requirement. Hence to utilize this diffused form of solar energy efficiently for heating in domestic or industrial applications, solar concentrators have to be used for generating temperatures in the range of 80–250 °C. The medium temperature applications can vary from domestic like cooking, boiling or dairy processes etc. to industrial like heat treatment, sterilizing, dyeing etc. This paper illustrates design and development of various concentrating solar thermal technologies along with its application in Indian market. The paper briefly reviews the need of such technologies; potential markets; and barriers and recommendations for deployment of available concentrated solar thermal technologies used for generation of medium temperature (80–250 °C). The paper focuses on the cases of successful implementation of the technology all over the country and also the government efforts to promote its use further for making it a cheaper and an alternative source of energy to fossil fuels for heating applications.
The thermal energy storage (TES) system using phase change materials (PCMs) has been studied since past three decades. PCMs are widely used in heat storage applications due to their high storage density, as well as the wide range of melting and solidifying temperatures. Nevertheless, the main disadvantage of PCMs, especially salt hydrates, is their corrosive behavior with container materials. PCMs are normally encapsulated in containers, hence the compatibility of the container materials with PCM plays an important role. As such, this paper summarizes the investigations made on the corrosion behavior of PCM in various applications, besides suggesting ways to reduce (or rectify) the effect for long term successful energy storage. Moreover, PCM-storage material interaction in the latent heat TES system is important as the issue of corrosion affects the life of the container, as well as the performance of TES. The compatibility of the most commonly used PCMs with several major container materials was reviewed and it was revealed that stainless steel has emerged as the most compatible storage container material among others. On the other hand, aluminum was found to be corrosive when it is used with salt hydrates. Nonetheless, some contradictory articles are reported that several salt hydrates demonstrated compatibility with container materials. Corrosion causes thinning of cross sectional area of materials, making it brittle thus leading to an easy collapse. This situation is even more critical mainly in large scale concentrating solar thermal power plants. Hence, with the fact that there are currently large scale power plants employing TES under operation and under construction; issues pertaining to PCM-storage material compatibility should be properly and accurately addressed. Therefore, more research work is recommended in the area of finding new eutectics and less corrosive container material(s).
In the world, the number of forcibly displaced people is arising. These people have several needs, especially in terms of food security. The humanitarian response usually focuses on food availability and access, while food processing is often neglected. In this framework, cooking technologies play an essential role. Many scientific studies and international reports address the issue of clean cooking technologies dissemination in developing countries. Less information is instead available in the literature for the specific case of humanitarian contexts, such as refugee and Internally Displaced Persons (IDP) camps, or informal humanitarian settlements. Unsustainable and inefficient cooking technologies or practices can have direct impact on food preparation, and indirect effects on local biomass resources overexploitation, health of local people, and social conflicts between hosted and hosting communities. This study aims at presenting a systematic review of both scientific and grey literature on cooking technologies and related practices, including a selection of experiences from the implementation of cooking devices in humanitarian projects and programmes. The Authors conclude that the attention to the problem is arising, but still very few information is available, in terms of scientific research.
In South Asia, a number of developing countries like India, Pakistan, Sri Lanka, Bhutan, Nepal, Afghanistan and Maldives are looking into inexhaustible and repeatable alternative energy sources such as solar, wind, hydro and biomass. Geographically, South Asian countries are located in a region of different climatic conditions such as tropical, humid etc. which provides easy access to a variety of renewable energy sources. The governments of South Asian countries have initiated renewable energy policies to encourage industries and individuals to employ renewable energy powered systems in power applications. This article provides an updated and comprehensive overview of the renewable energy status in the South Asian countries, and it includes an assessment of the region's renewable potential, current installed renewable energy capacity. This paper gives a brief description about energy scenario, renewable energy potential and challenges in South Asian countries. The study also provides the renewable energy policies and recommendation in South Asian countries.
The utilization of solar energy based technologies has attracted increased interest in recent times in order to satisfy the various energy demands of our society. This paper presents a thorough review of the open literature on solar energy based heat and power plants. In order to limit the scope of the review, only fully renewable plants with at least the production of electricity and heat/hot water for end use are considered. These include solar photovoltaic and solar thermal based plants with both concentrating and non-concentrating collectors in both solar-only and solar-hybrid configurations.
The paper also presents a selection of case studies for the evaluation of solar energy based combined heat and power generation possibility in Denmark. The considered technologies for the case studies are (1) solar photovoltaic modules, (2) solar flat plate collectors, (3) a ground source heat pump, (4) a biomass burner, and (5) an organic Rankine cycle. The various cases are compared on the basis of economic profitability and environmental performance. The results from the case studies indicate that it is economically and environmentally beneficial to invest in both small and large capacity solar-biomass hybrid plants for combined heat and power production in the Nordic climatic conditions. The results also suggest that the configuration with an organic Rankine cycle with solar thermal collectors and a biomass burner is particularly attractive for large capacity plants.
In this paper, the opto–geometric performance of fixed-focus solar concentrators (FFSCs), namely, the high temperature concentrator (HTC), the Scheffler concentrator and the Scheffler-type solar concentrator (STSC), is analysed. The goal of this study is to determine the behaviours of FFSCs as a function of their dimensions and to compare the results to the results of parabolic dish (PD) solar concentrators. An algorithm based on opto–geometric models of these concentrators was developed, and numerical calculations were performed for each type in a range of thermal power of 1–50 kW.
The numerical results indicate that FFSCs require a reflector with a diameter 45% larger than the diameter of a PD concentrator and increase the diameter of the solar image at the receiver by 350% compared with a PD concentrator. The increase in the diameter of the solar image by the fixed receiver in the FFSC produces a lower concentration. For thermal demands of less than 10 kW, FFSCs do not have significantly large dimensions. The proposed algorithm can be employed to evaluate the potential use of FFSCs and an FFSC instead of a PD concentrator because of the operational advantages of the fixed receivers of the different types.
The need to understand and proffer sustainable solutions to the persistent energy crises and energy starvation in Nigeria even in the face of abundant endowment of both renewable and fossil energy resources motivated this study. This study justified why solar energy should be accorded the highest priority as energy source in not only Nigeria but globally. A detailed review of the past, current and future status of solar integration in Nigeria is presented; it is seen that for grid-connected solar power integration the past status is nil, the current status is nil and future status may not be completely bleak as a number of Memoranda of Understanding have been signed. The existing supportive solar energy policies are highlighted and discussed; the chasm between the commendable Nigeria policy landscape and near-to-zero status of solar integration is blamed on poor implementation of the existing provisions by the Government. Recommendations were made on the basis of the existing policies and proposed policies. Additional provisions to some of existing laws of the Federation to accommodate support for solar energy integration are suggested. It is recommended that the poor and incipient status of solar integration in the vastly populated Nigeria should be viewed in a positive light by potential foreign investors as such status is a guarantee that solar power and thermal industry is a firsthand investment opportunity.
This paper discusses the thermal energy storage units, heat storage materials and cooking performance of solar cookers with heat storage surveyed in literature. It is revealed that rectangular and cylindrical containers are widely used in the heat storage devices of the solar cookers. The geometry of the storage units, however, depended on the mode of heat transport into the storage medium and out to the cooking vessel from which, three categories of solar cookers (2-stage, 3-stage, and 4-stage solar cookers) are identified. Furthermore, oils and organic phase change materials dominated in the sensible and latent heat storage units respectively. Additionally, the inclusion of high thermal conductive material into the storage medium was the principal technique used in enhancing effective thermal conductivity. Besides, it is shown that there is no significant difference between the cooking power of cookers equipped with sensible and latent heat storage units. However, the design parameters of the cookers as well as thermal diffusivity of the storage medium greatly influenced the cooking power. The 3-stage cookers outperformed their 2-stage counterparts whereas cookers with cooking vessels integrated to the thermal storage unit outperformed the ones with non-integrated cooking vessels. On the other hand, lower thermal diffusivity of the storage medium increased cooking power in cookers with sensible heat storage but decreased the cooking power in cookers with latent heat storage. Finally, it is shown that the quest for the development of high temperature thermal storage units, and the optimization of the geometry as well as heat transfer characteristics of thermal energy storage units remain the potential areas of research in heat storage for cooking.
Concentrated Solar Power (CSP) can be used as an efficient low cost energy conversion system to produce different types of energy, such as electricity, through the use of concentrated parabolic dish systems. In the study of CSP, most of the researchers focus on the heat losses and their relationships to the receivers' geometries. The present study concentrates on the optical efficiency as well as the flux distribution of the three different geometries: cylindrical, conical and spherical, of a cavity receiver, with the objective of analysing their behaviour using an advanced ray tracing method. The results of this study have shown that there is a connection between the flux distribution on the internal surfaces of the cavities and their optical efficiency. Moreover, the conical shape receiver received, as well as absorbed, a higher amount of reflected flux energy than the other shapes. The optical efficiency reached 75.3%, 70.1% and 71.5% for the conical, spherical and cylindrical shapes respectively at surface absorptivity of 85%. Also, the focal point location depends on the shape of the cavity receiver and its absorptivity. Thereby, there is an optimum distance for each design depending on these two factors. The results of the simulated work are validated using the experimental work found in the literature.
The optical performance of a solar dish concentrator/cavity receiver system based on the Monte Carlo Ray Tracing Method (MCRTM) was carried out under ideal optics. The study was precipitated by a need to analyze the influence of geometrical parameters and surface properties of a cavity receiver systematically and to understand the mechanism of the optical performance under various parameters. These include diameter ratio (the ratio of aperture diameter to absorber outer diameter), height ratio (the ratio of absorber height to absorber outer diameter) and sidewall absorptivity of cavity receiver. In addition, an optical efficiency of the absorber is defined and presented for the first time. The analysis indicates that the optical efficiency increases and then decreases with higher height ratio, while optical efficiency curves are reduced monotonically with diameter ratio. Simultaneously, the effects of the height and diameter ratios on optical efficiency are both influenced by sidewall absorptivity. Based on the results, a correlation of optical efficiency was further developed to quantify the influences of these factors. The maximum optical efficiency and its corresponding optimal height ratio from both simulation and correlation are presented and obtain reasonable agreement. The optimized selection of height ratio along with diameter ratio are suggested using this result. The height ratio is found to be a pure controlling parameter of the radiation flux distribution.
This article presents the results of computer simulations devoted to optimization of the high-temperature heat receiver, for concentrating solar radiation based on Ray Tracing method and computational fluid dynamics. The analyzed receiver is the part of the concentrating solar radiation helioenergetic installation. This installation uses two optical elements with different focal points. First goal was to determine the best location for the absorber within those focal points. To do it, a modified Ray Tracing method was used. Maps and graphs of the distribution of absorbed by receiver radiation intensity were generated. The data obtained was used in the computation of outlet working medium temperature flowing through the heat receiver. The computational fluid dynamics method was applied. Surface and spatial distribution of the temperature in the heat receiver and variations of the medium temperature were analyzed. The conducted research allowed for optimization of the concentrator-receiver geometry and selection of the optimal medium flow for the best optical system configuration.
The objective of the study is to examine the relationship between energy-resource depletion, climate change, health resources and the Environmental Kuznets Curve (EKC) under the financial constraint environment in the panel of selected developed countries, over the period of 2000–2013. The study employed panel Generalized Method of Moments (GMM) estimate for robust inferences. The results confirmed the existence of EKC hypothesis in the energy-resource depletion model i.e., inverted U-shaped relationship between energy-resource depletion and GDP per capita in the selected developed countries. The results of climate change model confirmed the U-shaped relationship of Perfluorocarbons (PFC) gas emission and Particulate Matter-2.5 micrometers (PM2.5) emissions with the per capita income. The health resource model confirmed the existence of inverted U-shaped relationship of infant deaths and health expenditures per capita with the per capita income, while there is a U-shaped relationship between incidence of Tuberculosis (TB) and GDP per capita. The other results indicate that carbon dioxide (CO2) emissions increase Sulfur Hexafluoride (SF6) emissions and health expenditures; fossil fuel energy consumption increases PFC gas emissions and PM2.5 emissions; energy demand increases PM2.5 emissions and health expenditures; and financial dummy (D2008) affected energy-resource depletion, PM2.5 emissions, Greenhouse Gas (GHG) emissions index, infant deaths, and health expenditures per capita.
Reflectors are a vital part of a concentrating solar thermal power plant. One of their most important characteristics is their durability, which entails the maintenance of their optical properties throughout their service lifetime, aimed at 10–30 years or more. The assessment of their optical durability involves the design of two types of aging tests, outdoor exposure testing under real ambient conditions and accelerated exposure testing in weathering chambers under simulated conditions. After exposure to different stress factors for certain periods of time, the optical performance of reflectors is evaluated mainly in terms of reflectance, but also regarding qualitative parameters such as their visual appearance and degradation patterns. The ultimate goal of a durability study is to conceive meaningful accelerated testing procedures that simulate real outdoor degradation in a short time and provide service lifetime estimates for a certain type of reflector at a specific site. To achieve this, more research on service lifetime prediction should be conducted and the standardization of accelerated testing procedures and reflectance evaluation methods should become widespread, to obtain comparable representative results. In this article, the most significant durability studies performed on the three main types of solar reflectors (glass-based, aluminum and silvered-polymer) and prospective approaches for improving future endeavors are discussed.
This paper reports the design details and performance studies carried out on five different types of solar cookers that were fabricated and tested at the Central Arid Zone Research Institute, Jodhpur. The study was undertaken to determine the cookers' potential usefulness. Two of them are of reflector type, two are of hot box type, and one uses the flat-plate collector. Of these five cookers, the hot box type solar cooker (solar oven) showed the greatest promise due particularly to its efficiency, ease of operation, ease of construction with local techniques, material, and simplicity.