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Design, construction and study of a hybrid solar food processor in the climate of Costa Rica
Abstract
During the last 25 years, the author has designed, constructed, studied and promoted solar oven, hybrid solar/electric oven, solar oven cum drier, solar cooker cum water heater and solar still. In different parts of the world, solar cookers have been made, studied, patented, however, their real uses are very limited due to many reasons—unstable climate, economic, cultural, social and single use, etc. In order to overcome part of the problems mainly the last one, author has recently designed one hybrid food processor (multi-purposes device) and studied various technical and practical aspects. It has been used for cooking, heating/pasteurizing water (to inactivate microbes) and distillation of small quantity of water (to remove different minerals) and drying domestic products (fruits, vegetables and condiments/herbs, etc.). For more than three years of use, author has found this to be a useful device, mainly from convenience, fuel saving, economic and also from ecological point of view. This device can be used at any time and for different uses but with the reduced consumption of conventional fuel.
... Levitation the vessel by providing a few lugs will make the bottom of the vessel a heat transfer surface This modification improves the performance of the SBC by improving the heat transfer rates. The times to reach saturation temperature and cooking were remarkably reduced Nandwani (2007) A multi-purpose hybrid solar food processor was designed and tested. The electrical energy was not estimated ...
... It also shows that the present system achieved the boiling temperature in a short span of time with respect to other models as well as feasible to cook a variety of edibles with reduced cooking times. It is notable that previous models of solar cookers (Hussain et al., 1997;Chaudhuri, 1999;Oturani et al., 2002;Rao and Subramanyam, 2003;Nandwani, 2007;Kurt et al., 2008;Misra and Aseri, 2011;Rao et al., 2001;Saxena et al., 2012;Cuce and Cuce, 2013;Sethi et al., 2014;Geddam et al., 2015;Joshi and Jani, 2015;Esen, 2004;Sharma et al., 2005;Hussein et al., 2008;Kumar et al., 2010;Panwar et al., 2010;Harmim et al., 2012;Singh et al., 2014;Soria-Verdugo, 2015;Mahavar et al., 2017) either performs on a quality thermal heat storage (sensible and latent) or direct electrical back-up for possible cooking. Although, evening cooking (for light stuffs only) is possible on a SBC by using PCM but it is a slow process and due to absence of solar irradiance or electrical back-up it could not be a long term process. ...
... This will work until the PCM gets completely discharge (i.e, 1-2 h only). There are few articles that demonstrate thermal performance improvement by improving the design of solar cooking unit or cooking vessels (Oturani et al., 2002;Rao and Subramanyam, 2003;Nandwani, 2007;Kurt et al., 2008). But the present improved design of solar cooker is better in terms of overall year round performance and can be efficiently used at any location of the world. ...
A new hybrid solar box cooker (SBC) has been developed and tested for thermal performance evaluation in climatic condition of western Uttar Pradesh, India. The uniqueness of new box cooker is an integrated trapezoidal duct and its other integrated elements. The objective of the study is to enhance the heat transfer rate and to reduce the cooking timings by consumption of minimum heat energy. For this purpose, a 200 W halogen lamp has been placed inside the duct to enhance the heat transfer. Besides this, 450 of small hollow balls of copper have also been used to improve thermal performance of SBC especially on forced convection mode. The performances testing have been carried to evaluate the thermal efficiency, figures of merit (F1 and F2), cooking power, heat transfer and overall heat loss coefficient. After completion of experiments, thermal efficiency of SBC has been observed 45.11%, cooking power is estimated to be 60.20 W and overall heat loss coefficient is obtained around 6.01 W/m² C. Results shows that the present design follow the BIS standards and can cook almost edibles in poor ambient conditions by consuming only 210 W. Discussion has also been made on the significance of the use of copper balls, fan and halogen lamp over the performance of SBC. The present solar cooker has been found as first kind of SBC which can efficiently perform on forced convection in any type of climatic conditions.
... Average specific heat between Tm and T 2 (kJ/ kg K) dt Change in temperature in °C m Mass of heat storage medium (kg) Q Quantity of heat stored (kJ) T 2 Final temperature (°C) T 1 Initial temperature (°C) Tm ...
... This solar energy can be used by means of photovoltaic (PV) cell or solar collectors. It has several uses like drying, space heating, cooking, electricity generations etc. [2][3][4][5]. And one of the well-known uses of solar energy is to cook the food [6]. ...
To run the Solar energy appliances, the continuous availability of solar energy is an essential. The Solar appliances are run by using solar energy either from PV cell or solar collector. Both of these devices require continuous solar rays. In order to use the solar energy after sunshine, it requires being stored first and then can be transferred to the appliances. One of the focused applications by using solar energy is the solar cooking. A Lot of research is going on the use of solar energy for cooking. But still, some extensive technique needs develop for easily usable systems. The various solar cookers are discussed to insist the need for development of solar storage systems for efficient cooking. This paper presents the comparative study of heat storage and transfer systems for solar cooking. The key aspects like, methodology to develop the heat storage system, requirements and properties of heat storage materials, need of insulations and their types are addressed. Some most usable materials are also analyzed.
... It was seen that the solar cooker utilizing non-tracking reflectors provided increased heat collection and faster cooking compare to the conventional box type cooker. El-Sebaii and Ibrahim [142] experimentally tested a solar box cooker for two different configurations under the weather [144] designed , constructed and tested a hybrid multifunctional solar cooking system in Costa Rica. The device proposed enabled cooking , drying and heating/pasteurizing purposes in a single system. ...
... Different types of solar ovens like fix cooker, bowl cooker, cone cooker, box type cooker and parabolic type cooker were constructed and tested in Nicaragua in fall of 2005 and the spring of 2006. Nandwani [144] designed, constructed and tested a hybrid multifunctional solar cooking system in Costa Rica. The device proposed enabled cooking, drying and heating/pasteurizing purposes in a single system. ...
... A judicious use of solar energy by means of solar cooking can cut down the cooking fuel expense by more than 60% and can help to overcome the harmful effects arising from the combustion of current "dirty" cooking fuels. A number of solar cookers have been designed and developed by many authors [5][6][7][8][9][10] so far, yet possibilities of improvement in the thermal performance of solar cookers which are subjected to the selection of materials for its components and design improvement, are still open. This paper presents extensive experimental studies of a Single Family Solar Cooker (SFSC) developed by authors. ...
... The cooking times of cooking test conducted during both winter and summer months for several food items are presented in Table 2. Fig. 2 illustrates that for different days of June 2009, within a very short time of 10 to 20 min bare plate temperature reaches 80 ºC and remain higher than 100 ºC for more than 5 h. On 17 June when the insolation was 945 W/m 2 and ambient temperature was 35 ºC, the stagnation temperature of bare plate was 144 ºC, which is comparable with the values reported by many authors [5][6][7][8][9][10] for their systems. Even on 18 and 19 June when insolation was significantly low (~ 800 W/m 2 ) and had significant fluctuation due to intermittent passage of clouds, the bare plate stagnation temperature remained around 120 ºC for more than 5 h which is reasonably long duration for satisfactory cooking. ...
This paper presents the design details and extensive experimental studies of a novel solar cooker, suitable for cooking requirements of a family of two or three persons; it is named as SFSC. Small size, good thermal performance, light weight and low cost are some important features of this cooker. The temperature profiles of various elements, without reflector, without load, and without reflector with load conditions for different days assure its good thermal performance and ability to cook two meals on a clear sunny day. The values of some essential thermal performance parameters viz. first figure of merit (F 1) and second figure of merit (F 2) suggested by Bureau of Indian Standards for a box type solar cooker are found to be 0.116 ºCm 2 /W and 0.466, respectively for the developed cooker. Cooking tests of several food items, performed during 2009 confirm year round good performance of this cooker.
... Solar cooking is a low-priced, smoke-free solution for many problems that have arisen and are increasing day-by-day because of the consumption of solid fuels. Although, several solar cookers have been designed, developed and studied by many authors (Vishaya et al. 1985;Nahar 1990;Grupp, Montagne, and Wackernagel 1991;Negi and Purohit 2005;Nandwani 2007;Kumar et al. 2008;Mirdha and Dhariwal 2008;Harmim et al. 2010), yet possibilities for improvement in the thermal performance of solar cookers that are subjected to the design improvements and the selection of more efficient materials to develop different components of the system are still open. ...
... A number of solar cookers have been designed and studied by different authors (Vishaya et al. 1985;Nahar 1990;Grupp, Montagne, and Wackernagel 1991;El-Sebaii and Ibrahim 2005;Negi and Purohit 2005;Nandwani 2007;Kumar 2008;Kumar et al. 2008;Mirdha and Dhariwal 2008;Harmim et al. 2010). The values of bare plate temperatures, ambient temperatures and insolations, which were observed during stagnation test by the authors for their systems, are listed in Table 3. Stagnation test results for SFSC-1 and SFSC-2 are also included in this table. ...
This paper presents the fabrication details and on-field experimental studies of two novel solar cookers, suitable for cooking requirements of small families; these are named as small family solar cookers (SFSC-1 and SFSC-2). Small size, good thermal performance, light weight, low-cost and short payback periods are some important features of these cookers. The values of some essential thermal performance parameters, first figure of merit (F1), second figure of merit (F2) and standard cooking power suggested by Bureau of Indian Standards and International Standard for box-type solar cookers, have been evaluated by experimental studies and found to be 0.116°C m2/W, 0.466, 30 W and 0.118°C m2/W, 0.488, 50 W for SFSC-1 and SFSC-2, respectively. A comparative analysis of the thermal performances of SFSCs with the solar cookers, developed by many authors, has also been presented here. The payback periods with respect to different cooking fuels for SFSCs have been found to be reasonably short.
... A judicious use of solar energy by means of solar cooking can cut down the cooking fuel expense by more than 60% and can help to overcome the harmful effects arising from the combustion of current "dirty" cooking fuels. A number of solar cookers have been designed and developed by many authors [5][6][7][8][9][10] so far, yet possibilities of improvement in the thermal performance of solar cookers which are subjected to the selection of materials for its components and design improvement, are still open. This paper presents extensive experimental studies of a Single Family Solar Cooker (SFSC) developed by authors. ...
... The cooking times of cooking test conducted during both winter and summer months for several food items are presented in Table 2. Fig. 2 illustrates that for different days of June 2009, within a very short time of 10 to 20 min bare plate temperature reaches 80 ºC and remain higher than 100 ºC for more than 5 h. On 17 June when the insolation was 945 W/m 2 and ambient temperature was 35 ºC, the stagnation temperature of bare plate was 144 ºC, which is comparable with the values reported by many authors [5][6][7][8][9][10] for their systems. Even on 18 and 19 June when insolation was significantly low (~ 800 W/m 2 ) and had significant fluctuation due to intermittent passage of clouds, the bare plate stagnation temperature remained around 120 ºC for more than 5 h which is reasonably long duration for satisfactory cooking. ...
This paper presents the design details and extensive experimental studies of a novel solar cooker, suitable for cooking requirements of a family of two or three persons; it is named as SFSC. Small size, good thermal performance, light weight and low cost are some important features of this cooker. The temperature profiles of various elements, without reflector, without load, and without reflector with load conditions for different days assure its good thermal performance and ability to cook two meals on a clear sunny day. The values of some essential thermal performance parameters viz. first figure of merit (F 1) and second figure of merit (F 2) suggested by Bureau of Indian Standards for a box type solar cooker are found to be 0.116 ºCm 2 /W and 0.466, respectively for the developed cooker. Cooking tests of several food items, performed during 2009 confirm year round good performance of this cooker.
... Solar cooking is a low-priced, smoke-free solution for many problems that have arisen and are increasing day-by-day because of the consumption of solid fuels. Although, several solar cookers have been designed, developed and studied by many authors (Vishaya et al. 1985;Nahar 1990;Grupp, Montagne, and Wackernagel 1991;Negi and Purohit 2005;Nandwani 2007;Kumar et al. 2008;Mirdha and Dhariwal 2008;Harmim et al. 2010), yet possibilities for improvement in the thermal performance of solar cookers that are subjected to the design improvements and the selection of more efficient materials to develop different components of the system are still open. ...
... A number of solar cookers have been designed and studied by different authors (Vishaya et al. 1985;Nahar 1990;Grupp, Montagne, and Wackernagel 1991;El-Sebaii and Ibrahim 2005;Negi and Purohit 2005;Nandwani 2007;Kumar 2008;Kumar et al. 2008;Mirdha and Dhariwal 2008;Harmim et al. 2010). The values of bare plate temperatures, ambient temperatures and insolations, which were observed during stagnation test by the authors for their systems, are listed in Table 3. Stagnation test results for SFSC-1 and SFSC-2 are also included in this table. ...
... After using it more than 3 years, the author found that to be a useful device, mainly for convenience, fuel saving, economical and also from an ecological point of view. The device could be used at any time with a backup of auxiliary power [19]. Kumar and Tiwari have designed and tested a new selfsustainable hybrid PV/T integrated active solar still. ...
... The energy balance of the HSES is almost comparable to the normal solar energy device. The total energy input to the whole system due to the sun Q s: Q s = Q loss + Q use (19) Q use = Q s -Q loss (20) Q use = I × A p × (τα) -A p × U L × (T ws -T amb ) ...
... To speed up the drying process of agricultural products, the solar dryer can significantly increase the outside air temperature. Unlike products drying in the open, products within the dryer require less care from the sun, rain, and pests (both human and animal) (Nandwani, 2007). The daily efficiency of the air-heating solar collector with a storage bed may be used to determine its daily average characteristic parameters (Bennamoun & Belhamri, 2003). ...
Studying an innovative machine design project that focuses on assembling plant leaves into compact rolls requires the application of engineering principles and sustainable technologies to develop a leaf-processing and assembling machine. The description of different machine components and operations, along with their potential applications, energy efficiency, and contributions to sustainable waste management, are discussed in detail.
Literature is thoroughly carried out to explore the existing machines and their different aspects based on their applications. The parametric study on leaf-processing and assembling machines is reported briefly regarding tabulation and graphs.
Several aspects of the process of developing leaf-processing machinery are being investigated. These include machine design, the function of automation in enhancing precision and productivity, and the environmental impact of machines to reduce carbon emissions and boost biodiversity by making environmentally friendly use of plant waste. Additionally, reports include economic and market analyses of these machines.
A critical review was carried out successfully to integrate and adopt the leaf processing machine for sustainable waste management, which includes the creation of regulatory frameworks, educational initiatives, ongoing research and development, scalability assessments, stakeholder collaboration, monitoring and evaluation mechanisms, international engagement, and community involvement.
... The energy efficiency of the STEPCO oven was estimated using Eq. (8) [48]. ...
... Nandwani [120] 2007 Hybrid Solar-Food Processor A hybrid food processor that serves many functions was created, and its different technical and usable elements were researched. Cooking, pasteurizing water, distilling small amounts of water (to remove various minerals), and drying household goods (fruits, vegetables, condiments/herbs, etc.) ...
Drying via solar energy is an environmentally friendly and inexpensive process. For controlled and bulk level drying, a greenhouse solar dryer is the most suitable controlled level solar dryer. The efficiency of a solar greenhouse dryer can be increased by using thermal storage. The agricultural products dried in greenhouses are reported to be of a higher quality than those dried in the sun because they are shielded from dust, rain, insects, birds, and animals. The heat storage-based greenhouse was found to be superior for drying of all types of crops in comparison to a normal greenhouse dryer, as it provides constant heat throughout the drying process. Hence, this can be used in rural areas by farmers and small-scale industrialists, and with minor modifications, it can be used anywhere in the world. This article provides a comprehensive analysis of the development of solar greenhouse dryers for drying various agricultural products, including their design, thermal modelling methods, cost, energy, and environmental implications. Furthermore, the choice and application of solar photovoltaic panels and thermal energy storage units in the solar greenhouse dryers are examined in detail, with a view to achieving continuous and grid-independent drying. The energy requirements of various greenhouse dryer configurations/shapes are compared. Thermodynamic and thermal modelling research that reported on the performance prediction of solar greenhouse dryers, and drying kinetics studies on various agricultural products, has been compiled in this study.
... In 2007, Nandwani [1] designed a multi-purpose system (also referred to as hybrid food processor) evaluating various technical and practical aspects. The author assessed the performance of the system in Costa Rica according to different working modes: a) as a solar cooker; b) to pasteurize water; c) as a solar dryer; d) as a solar still. ...
Performance parameters of solar cookers have conventionally been determined by assuming a linear trend between the cooker power and the difference between load temperature and ambient air temperature. This approach may not be convenient for some solar cooker designs. In the present work, the suitability of a non-linear regression derived from fitting the measured load temperature to a second order exponential polynomial was investigated and compared with the linear regression. Both regressions were compared with the corresponding experimental curves of a panel cooker and a box cooker. In the case of the panel cooker, the linear trend of the experimental plot was confirmed over a large period of the conducted test. Minor deviations from the experimental data were observed only at the beginning and at the end of the test. On the contrary, in the box solar cooker, significant deviations between the linear regression plot and the experimental points were observed, while smaller deviations were obtained using the non-linear regression. Thus, the proposed method can be seen as a promising approach that should be considered when updating the existing procedures for testing and reporting the performance of solar cookers.
... A cylindrical single glazed with a plane reflector box-type sun-powered cooker with one cooking pot was developed and tried by Kurt [39] under the predominant climate conditions in Karabuk, Turkey. Nandwani [40] designed and analyzed a half-breed multi-reason sunlight-based cooker, which is utilized for food making, for warming up the water to inactivate organisms and refining procedures to evacuate different minerals and items drying. Schwarzer and Vieira da Silva [41] analyzed general sorts of sun-oriented cookers, their fundamental attributes, and experimental systems to test the various kinds of sun-powered cookers, and they proposed a simplified analytical model to plan a basic cooking framework. ...
Cooking is one of the most common activity in day-to-day life of every woman. In rural areas the transportation of fuel is major problem and the increasing demand of energy for cooking applications is gaining importance and various investigations are being carried out for performance enhancement of the solar cooker. The box-type solar cooker has a complex thermal analysis due to the transient heat transfer phenomenon involved in three dimensions. A comparison of the standard correlation available are analysed for accuracy of predicted results with experimental data. The investigation involves the experimental determination of the parameters viz. wind heat transfer coefficient, side and bottom loss coefficient, inner and outer glass temperature. The extensive data is analysed with that of standard correlations and the significance of the experimental data is checked. Analysis found to have deviation of 3%-20% in experimental and correlation data, which indicates that for accuracy of performance analysis the studied parameters should be determined experimentally.
... Various researchers have made a number of previous attempts to introduce hybrid cookers. Some of these attempts (Nandwani 2007) tested a hybrid solar-electric food processor in the climate of Costa Rica. Quiroga et al. (2019) presented the design, construction and thermal evaluation of a hybrid solar oven with biomass as an auxiliary source of energy. ...
This paper presents a computational study of a novel biomass-solar combined cookstove for developing countries. A computational fluid dynamics (CFD) study was carried out to understand how the proposed cookstoves perform during combustion. The technique was successfully used for predicting the temperature and the flow velocity distribution within the interior of the stove. The results showed that the flame diffused in the combustion chamber reached the maximum temperature of 1550 K and then decreased as the flue gases flowed upward through the distance from the flame zone to the outlet. Velocity distribution and CO2 concentration predictions are presented. The maximum flow velocity in the combustion was found to be 0.217 m/s. The performance of the stove demonstrated that this cookstove can be a novel alternative for households who have low access to electricity and traditionally depend almost completely on biomass fuels.
... Effective thermal efficiency is from 23% to 32%, depending on the mode of operation. Nandwani indicates that electric power consumption is minimal because it is used only to complete cooking when solar energy is insufficient [13]. ...
Solar energy for cooking is an interesting option to achieve energy efficient cooking, while reducing environmental impact and facilitating nutritious cooking on a daily basis, especially to provide nutrition for young children. Solar oven delivers high thermal performance running on solar energy alone on clear days. On cloudy days, the amount of solar energy is not enough to use the solar oven. Therefore, it is necessary to cook with electricity, gas or firewood, which breaks the continuity of the use of the solar oven. Then, when it is possible to use the solar oven again (on the subsequent clear day), it is difficult because of the habit established of fuel use. The hybrid oven (solar + biomass) allows for cooking every day of the year (clear or cloudy), with the same device, even at night. This paper presents the design, construction and thermal evaluation of a hybrid solar oven with biomass as an auxiliary source of energy. The basis is the drum solar oven, widely used for its characteristics: easy to build, efficient performance and optimum cooking capacity. It incorporates a specially designed appliance which takes advantage of the biomass and generates energy efficient cooking. Thermal tests are carried out to determine the characteristic parameters: figures of Merit F1 =0.100; F2 =0.253, standardized cooking power for 50°C, 31.2 W, and cooking efficiency 23.3% for operation only with solar energy and standardized cooking power for 50°C, 378.3W and cooking efficiency 5.8% for the oven with hybrid operation. Temperatures reached by the absorber plate are 120°C for solar-only energy operation and 173°C for hybrid operation. These temperatures do not endanger the integrity of the materials used. Only a minimum amount of energy is needed to reach the necessary temperature and power for cooking. It is therefore an interesting and economical solution for all communities of any climatic condition, especially those that are isolated from energy supply networks.
... It is essential that process of solar cooking should continue even during small interruptions in radiations and therefore, lower reference cooking temperature should be above 82.5°C which is fortunately above the pasteurization temperature of 69°C as well (Nandwani, 2007). Accordingly, 85°C has been taken as the lower reference cooking temperature for the solar cooking of rice. ...
One of the big challenges in the solar cooking process is ensuring the completion of cooking process under unexpected
reduction in the sunshine due to cloudiness. The popularity of solar cookers is hindered because of the uncertainty in the accomplishment of cooking process, resulting in spoilage of food and wastage of time, leading to inconvenience and loss. The completion of cooking activity certainly requires a definite amount of stored heat
at above the cooking temperature and a parameter to provide the related information for design incorporation.
Because of the complex nature of the cooking process, the present work considers rice as the food item. In the process, it proposes an alternative to heating based test procedure to determine more realistic value of thermal performance parameter (TPP) for the solar cookers. The relevant parameter is determined utilizing novel cooling test. Two different designs of cookers have been tested to establish the proposal.
... These were fixed on the underside of the aluminum tray to provide uniform heating through a servo stabilized electric power supply. Nandwani [39] has designed one hybrid solar food processor (multi-purposes device) and, has studied various technical and practical aspects of that system. This hybrid solar food processor has been used for cooking, heating, pasteurizing water, distillation of water and drying domestic products. ...
The major hindrance in popularization of box type solar cookers (SBCs) is cooking incapability of these appliances in low availability of sun light and in night. This paper introduces a new parameter “required electric back-up power (Prb)” for SBCs to remove this limitation. An analytical model is presented here to derive Prb for SBCs under different weather and cooking time conditions. To validate proposed model, a Solar cum Electric Cooker (SEC) has been fabricated as per Prb value estimated via analytical model. SEC has been tested under different conditions. Experimental results are in support to the analytical approach. SEC is capable for cooking of 1.2 kg food load under indoor and outdoor. For outdoor, cooking time on sunny day without back-up is recorded between 1.5 and 2.5 h. The cooking time on scattered cloudy day with back-up is found to be 100 min (back-up is 0.12 kWh that is 82% less than the conventional electric heater). For indoor, cooking time is found to be 85 min (with 0.23 kWh electric back-up). Paper also reveals that electric back-up in SBC also reduces its payback period and increases its net present value (NPV) in respect to different cooking fuels.
... Hosny and Abou-Ziyan designed, constructed and carried out tests on two full tracking solar cookers, namely a paraboloid dish solar cooker (PDSC) and a booster mirror solar box cooker (BMSBC) [79]. Harmim A et al. [80,81] used a solar cooker equipped with an asymmetric CPC (Compound Parabolic Concentrator) consists of an insulated box with a vertical double glazing cover on a side and two linear parabolic reflectors (upper and lower parabola) fixed on the glazed side of the box. ...
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.
... Results of cooking trials and stagnation temperatures have also been reported by Nahar [11] for a storage type solar cooker. A non-tracking concentrator model of Negi and Prohit [12], a hybrid solar food processor of Nandwani [13] and a truncated pyramid type solar cooker of Kumar et al. [14] are several other box type solar cookers which have been well studied. ...
This paper presents the design development and, thermal and cooking performance studies of a novel solar cooker; it is named as Single Family Solar Cooker (SFSC). Small size, convenient design, inexpensive lightweight hybrid insulation and specially designed lightweight polymeric glaze are the main features of this cooker. A complete theoretical consideration for the fabrication of SFSC has been presented. The thermal profiles of various components of SFSC on different days under different conditions have been measured. During testing, the highest plate stagnation temperature, under no-load condition, approached 144 °C. The two figures of merits F1 and F2 are found to be 0.116 °C m2/W and 0.466, respectively, which are according to the Bureau of Indian Standards. The cooking power regression curve is fairly linear with the regression coefficient R2 = 0.948. Initial cooking power 103.5 W and the heat loss level 1.474 W/°C, place it in the region of small cooker with good insulation, as per International Standard. Cooking tests of several food items performed during 2009 confirm year round good performance of this cooker.
... The efficiencies for each unit of use were calculated through the use of energy balance equations. This "four in one devices" was found to be a simple solution to fuel and food problem [94]. Kurt et al. have conducted some experiments on two different model box type solar cookers which were in rectangular and cylindrical geometries, constructed using the same material. ...
... The solar energy is being effectively used in India and China. The largest numbers of cookers are in India and China: more than 340 000 in India and 140 000 in China (Nandwani, 2007 and references there in).The present research deals with the improved design of slope type electric cum solar oven. In a previously reported work an electrical cum solar oven had resulted in 15% efficiency (Sengar and Kurchania, 2007). ...
In the present work we report the design and fabrication of an improved electric cum solar oven (ECSO) in which both solar energy and electricity has been utilized as energy source. The design consists of a tilted upper glass cover rectangular shape and the angle of slope 30 degree. The electrical heating was used in conjunction with the solar energy to make the oven useful during the periods of lesser sunshine. The temperature of the oven has been controlled using a thermostat. The oven has been found useful for cooking conventional food items in a very reasonable time under the local environmental conditions of Faisalabad city.
... Bennamoun (2003), presented the effect of surface of the collector, the air temperature and the product characteristics during solar drying of onion. Nandwani (2007), has discussed the design and development of a multipurpose fruit and vegetable dryer for domestic use. ...
Solar radiation in the form of solar thermal energy, is an alternative source of energy for drying especially to dry fruits, vegetables, agricultural grains and other kinds of material, such as wood. This procedure is especially applicable in the so‐called “sunny belt” world‐wide, i.e. in the regions where the intensity of solar radiation is high and sunshine duration is long. It is estimated that in developing countries there exist significant post‐harvest losses of agricultural products, due to lack of other preservation means. Drying by solar energy is a rather economical procedure for agricultural products, especially for medium to small amounts of products. It is still used from domestic upto small commer‐
cial size drying of crops, agricultural products and foodstuff, such as fruits, vegetables, aromatic herbs, wood, etc. contributing thus significantly to the economy of small agricultural communities and farms.
... Esen [18] has studied the thermal performance of a solar cooker having integrated vacuum-tube collector. Nandwani [19] has designed a solar cooker for multiple applications. Significant work has also been carried out on finned cooking vessel and absorber tray by Harmim et al. [17,20]. ...
This paper presents modeling, fabrication and on-field testing of a Solar Rice Cooker (SRC). Modeling includes the development of a theoretical formalism to compute available solar power (qa) from different components of the system; describes suitable component materials and also includes the load dependent performance analysis of the system for rice cooking. Essential constraints on available energy and cooking time for assured cooking and their interrelationship with system parameters have been deduced and discussed at length. Using the solar geometry, the value of qa has been computed theoretically on equinox day. It varies from 82 to 120 W and its average value is about 107.8 W for the duration 10:00 to 15:00 solar time. As per modeling SRC has been fabricated and its on-field testing has been performed on various days under different conditions. The maximum temperature attained by container's top surface is 142 °C. The rice cooking time for first and second meal is found to be 2 h and 2 h 20 min, respectively. The payback period and NPV (net present value) have also been computed for SRC. With light weight 6 kg, reasonable cost 2500 INR, high NPV and short cooking time SRC is a suitable rice cooking appliance.
... The efficiencies for each unit of use were calculated through the use of energy balance equations. This "four in one devices" was found to be a simple solution to fuel and food problem [94]. Kurt et al. have conducted some experiments on two different model box type solar cookers which were in rectangular and cylindrical geometries, constructed using the same material. ...
Globally there is profuse literature on the continuous developments of box type solar cookers and solar ovens. A lot of research work has been carried out in recent passed years in the world which clearly shown the utilization of solar energy towards the greatest needs of mankind obviously solar cooking, fuel saving, non-polluting environment and to save and produce electricity. In the present literature the efforts have been made to focus on diverse developments of box type solar cooker till now. An attempt has been made to optimize the various major parameters such as geometries of box-cooker, glazing system, cooking vessels design, heat storage, insulation, mirror boosters and financial feasibility of solar cooker box. All the discussed factors have been taken into account in the fabrication of a simple solar box cooker and a good improvement has been found in the performance of box cooker with efficient working in low ambient temperatures. A wiper type mechanism to remove vapor droplets from the bottom of glazing, during the cooking process has been introduced and discussed with a new designed cooking vessel. The investigational testing of the fabricated box cooker has been carried out under the climate conditions of Moradabad (latitude - 28°58'north and longitude - 78°47'east) Uttar Pradesh.
The present work reveals a solar thermal collector’s (STC) novel design and its use for intermediate-temperature
solar cooking. The main aim of the work is to demonstrate the usefulness of the proposed collector in attaining
intermediate temperatures for decentralized energy applications, providing multiple sustainable energy solutions.
The opto-thermal performance of the STC for cooking is evaluated using thermal performance parameter
(TPP) based testing and rating. The impact of design-induced change on the performance is assessed by testing
two configurations of STC for cooking. The effective concentration ratio (Ceff) is estimated using the thermal
method. The levelized cost of solar-cooked meals (LCSCM) demonstrates the techno-economic feasibility of the
proposed collector for cooking.
The results showed that the value TPP, cooker opto-thermal ratio (COR) for the first and second configurations
are 0.116 and 0.108 (m2⋅◦C)/W, respectively. Also, the value of Ceff is 1.074. The LCSCM value for the best
configuration is 0.0323 USD/Ml.
Therefore, the present work provides valuable insights into developing and testing an efficient design of STC
for multiple applications and provides recommendations for its future use for several other applications, such as
drying, air and water heating, and a few more.
In the background of the COVID 2019 pandemic, the importance of developing realistic and efficient decentralized energy solutions is one of the essential requirements. This paper presents the performance of a small-scale solar box cooker cum dryer (SBCD) for decentralized communities and domestic scale applications. The drying process in SBCD uses a simple and effective method for moisture removal. It enables de-moisturization of the cooker interior, allowing efficient use of SBCD for the simultaneous dual-mode operation of cooking and drying. Cooker Opto-thermal Ratio (COR) as a thermal performance parameter and glycerin as a test load enable cooking process analysis. COR-based objective parameters (OPs) realistically comment on the cooker performance in the dual-mode operation. Drying kinetic studies describe the drying performance of the device. The levelized cost of cooking meals (LCCM) allows understating of the economics of SBCD.
The mean value of COR for the cooker is 0.104 ± 0.0028 (m2·°C)/W with a percentage standard deviation of 2.69%. The experimental values of OPs, reference cooking time, and maximum achievable load temperature varies between 74 and 86 min and 103–111 °C, respectively. Thus, SBCD cooks in approximately 80–90 min and dries ∼ 100 g of food products simultaneously with 70–80 % moisture removal. The LCCM for SBCD is $ 0.0174 per meal. Thus, SBCD depicts a realistic solution for ensuring self-sustainability in decentralized communities.
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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
Utilization of Carbon Dioxide for Preparation of Polyurethanes without Using the Toxic Isocyanates
Warming meal at educational centers for students is done with microwave ovens consuming high energy and making long queue. Conventional hot box solar ovens can warm meal using free, abundant and clean Solar energy, during 10-11 months in a year in many places in Costa Rica. For the rest of the periods, if heating is required one can use Microwave Ovens. Different types of pots which can be used both in Solar and Microwave ovens have been searched and are studied. Due to pandemic period experiments have been done at authors house for measuring oven, meal temperature with solar radiation and with different pots. The heating of 14 lunch boxes is done with one solar oven and even simulating the clouds to see the performance and results are very promising. Due to COVID during 2020 and 2021, the classes were virtual, thus the real heating could not be done in any college to see the acceptance by the students and staff. We plan to promote see the real performance during 2022.
This paper aims to combine the applications of cooking and hot air generation in single box-type solar cookers to reduce environmental pollution and to save energy, cost and space. Because of the combined effect, a 33.42% improvement in efficiency is obtained. An innovative dodecagon shape of frustum concentrator is introduced which increases efficiency by 6.3% compared to conventional mode. Different types of pan (i.e. receiver) materials like Mild steel and Aluminium are analyzed. The usage of Aluminium leads to a 4.27% increase in total efficiency compared to Mild steel pans. The effect of internal fins in Aluminium pans is studied which leads to 3.59% increment in the efficiency of cookers compared to the aluminium pan without fins. The combined 2 in 1 effect leads to a reduction of 272 kg of CO2 emission per year and the simple payback period of the cooker is 10 months.
In this study, a theoretical analysis of food processing (e.g., solar drying), worldwide cooking pattern, and cooking methods by using the solar energy has been reviewed. Solar food processing method is applied as direct absorption, air heater, and a combination of direct and indirect drying by solar radiation. Therefore, this process is one of the most accessible and hence the most widespread processing technologies. Traditional solar drying involves keeping products in the direct sunlight. Solar drying and cooking processes take place at different temperatures and timescales, and it depends on the nature of the food or substance. The amount of solar energy that reaches to the system and design parameters determines the performance of food processing and cooking systems. The time duration of drying and cooking depends on the temperature of heated air and environment. The temperature distributions, mass, and ingredient of food have an important role in the performance of dryers and cooker boxes. For a better understanding of the system parameters, the concept of solar food processing has been discussed thermodynamically. Energy saving by using solar systems has also been discussed.
Conventional methods to obtain solar radiation data are from weather stations, from solar radiation models, from commercial software databases and from field measurements. Few studies have been presented to compare the results from the four mentioned methods. Considering this, new daily diffuse solar radiation models for Northern China climates are first established in this study. The solar radiation models are then compared with open-access weather station data from China Meteorological Data Sharing System (CMDSS), with TRNSYS database data and with measured data in Xi'an. TRNSYS supplies the Typical Meteorological Year data, while the solar radiation models give the long-term annual average results. It is found that combining the sunshine duration and the day of the year together can establish a group of accurate diffuse solar radiation models. Good agreements are found between the CMDSS and the newly established solar radiation model calculating daily diffuse solar radiation. The diffuse solar radiation estimated by TRNSYS is a bit higher than that from the open-access website in summer half year. TRNSYS supplies the highest annual diffuse solar radiation. The TRNSYS database is of high significance to a solar system performance evaluation. The solar radiation models can be used for the solar system design.
Since 1979, the author has designed, studied and used various models of solar cookers—from thermal food warmer in 1979, to PV multi-voltage cooker in 2010 and to single-axis tracker for solar cookers in 2012. Besides publishing the results in technical journals and national and international conferences, these have been promoted through lectures in communities, educational and cultural centres, TV, radio, newspapers, workshops and seminars in Costa Rica and many other countries. For one of the models of solar cooker, the author got a patent in 1984.
In the present work, different models and some promotional activities, especially at educational institutes, to warm the lunch for students are mentioned.
In order to solve the problems in traditional drying technology of preserved fruits, a mini all-weather solar dryer was designed and manufactured based on characteristics and requirements of preserved fruits produced in Guangdong province. The solar dryer is composed of heat-collection plate, drying chamber and blower. It can collect sun radiation to heat air and water, store heat through hot water tank. It also has an assistant heating system in water tank. Forced air convective drying, natural convective drying and greenhouse drying can be reached by the designed dryer. The experiments of drying Ganshimei (intermediate moisture salted plum) were carried out to test the dryer's performance. The working efficiency of heat-collection plate and drying chamber, the material balance and energy consumption of the drying system were calculated. And the parameters of the dryer were determined. The total drying efficiency of the forced air convective drying reached to a high level of 63.40%.Comparing with the traditional open sun drying, the drying rate of the forced air convective drying was 9.99 g/(100 g·h), which was 201.2% of the open sun drying's. And the drying time of the forced air convective drying was 12 h, much less than 50 h of the open sun drying's. Meanwhile the sugar and acid content loss of the forced air convective drying samples were less than that of the open sun drying samples.
In the present energy scenario utilization of Solar Biomass Hybrid System proves to be the need of the day. Twenty percent of fossil fuel gets depleted by 2020. Also India is a tropical country and agriculture is one of the important sectors to develop our economy. This paper deals with the research in the area of effective utilization of alternate energy resources for agricultural applications in the rural area. In this investigation a solar flat plate collector supplies hot air for a batch type drier. Suitable draught is provided with a help of a D. C. Fans. Additionally a D.C. Blower is provided for proper circulation of air through a Bio-mass gasifier which supplies heated air in the cloudy days. According to the need either solar air drier or Bio-mass gasifier can be used separately or both can be utilized as an integrated system. Experiments have been conducted on various solar days for drying various batches of cashew using solar air drier and bio- mass gasifier separately as well as in hybrid mode and the results are analysed and the findings are presented.
The natural convective drying of Ganshimei (intermediate moisture salted plum) was performed using the self-designed small-size solar drying equipment, and the corresponding experimental parameters were detected. Then, the material and energy consumption of the drying system were calculated. Finally, a mathematical model describing the natural convective drying was put forward by changing the effective solar radiant energy per unit. The results show that the natural convective drying using the designed equipment, whose drying efficiency is 61.60%, is of a time cost of 14h, which is only 28.0% of that of the traditional sun drying; and that the proposed model accords well with the experimental results, with a relative deviation being less than 1%. This paper provides the theoretical basis for the application of solar drying equipment and for the quality prediction and drying condition control of Cantonese-style preserved fruits.
In Argentina there exist children’s dining rooms where infants and their mothers take lunch at noon and glasses of milk in the afternoon. These dining rooms are established in rural or marginal urban areas. Solar ovens are an interesting option for cooking with less expense of money, and they diminish environmental impact in these zones. A solar oven with downward and upward solar gain was built and tested. Upward solar gain is through Fresnel reflectors. The use of Fresnel reflectors resulted in higher heating power as compared to a solar oven with upper reflectors only. The performance with different numbers of Fresnel units was compared with a single-reflector solar oven with no lower Fresnel reflectors. Oven power was analysed and the result indicates that power grows as the number of Fresnel reflectors increases: it grows by 55% using 3 to 9 Fresnel reflectors, and by 34.6% with 3 to 6 Fresnel reflectors. These values are enough to cook several rations of food, and make this oven appropriate for use in dining rooms in developing countries.
Energy for cooking is a major concern of consumers and policy makers in India. Most of the cooking in rural India is done using biomass. Traditional biomass stoves cause significant greenhouse gas (GHG) emissions due to formation of products of incomplete combustion. As far as urban population is concerned, around 95% of the population has access to LPG as cooking fuel at subsidized rates. To increase accessibility of LPG to rural areas is economically incompetent option when compared with the solar and biogas as other options available in rural areas.In this paper, an effort has been made to review the developments occurred in cooking sector rural areas in Indian context. The work carried out on different cooking fuels and cook stoves has been presented in order to use renewable energy sources and to identify the barriers of their dissemination. The status of cooking sector in India and the initiatives taken by the government of India has also been discussed and presented in the paper. It has been observed that the government of India is running several programs for the promotion of solar and biogas as cooking fuels in rural areas and it has succeeded to an extent.
The use of solar energy in recent years has reached a remarkable edge. The continuous research for an alternative power source due to the perceived scarcity of fuel fossils is its driving force. It has become even more popular as the cost of fossil fuel continues to rise. The earth receives in just 1 h, more energy from the sun than what we consume in the whole world for 1 year. Its application was proven to be most economical, as most systems in individual uses requires but a few kilowatt of power. This paper reviews the present day solar thermal technologies. Performance analyses of existing designs (study), mathematical simulation (design) and fabrication of innovative designs with suggested improvements (development) have been discussed in this paper.
As in most of the developing countries, 35–40% of the population of Costa Rica still use firewood for domestic cooking. Considering the fact that Costa Rica is blessed with good sunshine, high hydroelectric potential and there exists a good electric network, a hybrid solar oven was thought to be useful. In the present paper the construction and working of one electric cum solar oven (ECSO) has been described. This oven can be used for cooking and baking almost all types of meals at any time during the year employing solar and/or electric energy and consuming the minimum quantity of electric energy when it is required.
With the aim to test and compare some properties of materials and common geometries that are used for designing solar cookers, water heaters, etc. we have made a solar hot box with two similar compartments. In the present study this hot box has been used for, (a) comparing the behavior of a metallic slab filled with a phase change material for short term heat storage, with a conventional absorbing sheet, (b) the use of a selectively coated, as compared to a normal black painted, cooking pot, and (c) for finding the overall heat loss coefficient and thermal capacity of the box. Experiments with the solar hot box will yield valuable information on solar systems that are to be constructed. Besides its use for research this multipurpose device has been used both to pasteurize up to 14–16 l of water and for cooking.
Inexpensive and easy to fabricate solar ovens have been made with available materials. One reflector has also been mounted to increase the input radiation on the hot absorbing plate which can be adjusted manually according to the need. This has been used by the author for the last 7 years to cook almost all types of vegetables, including rice, pulses, chicken, fish and beef and to bake bread and cake etc. Experimental studies have also been made on the variation of plate temperature, solar intensity, time to cook vegetables. These are given for the various cases of adjustment of the oven, depending on the convenience for the user. Furthermore, the insulating properties of the cooker are also studied. Maximum plate temperature observed was between 130 and 150°C and one cooked meal for a family of four persons can be made in 2–3 h. Thermal efficiency and heat loss coefficient, deduced from these measurements, varies between 30–40% and 4–9 W/m2°C. Simple theoretical analyses have beend used to explain these experimental data, taking into account heat capacity of various materials. The agreement is fairly good. Finally, some practical conclusions have been drawn.
In many communities of the developing countries, including Costa Rica and especially in coastal areas, there exists s shortage of potable water. Taking into account the fact that transportation/distribution of potable water is expensive for these communities and most of these places are blessed with good sunshine, one domestic solar still per family could help in getting fresh water—at least for drinking purposes (say 10 1 per day). Although the design, construction and technical results of three small-scale solar stills studied by the author have been presented in local technical journals, these results are mentioned briefly and are used for the estimation of total quantity of water distilled per year in three different climates of Costa Rica. In one study, estimation of rain water collected over the glass cover of a solar still has also been made as this can be considered as drinkable water where potable water is not available. In the present work, economic analysis of these stills have been made at these places in Costa Rica—not to show that cost of water produced from these stills is expensive compared to a conventional centralised system (including subsidies), but to see how expensive it is. Comparisons have been made with distilled water produced from a domestic electric still. It has been found that the cost of water produced from the solar still is 15–30 times more expensive than sold presently by the centralised system, however, it is far cheaper than produced by the electric still. Another objective of this study was to produce a basis for the construction of various small stills or one big plant for one community, e.g. Island Chira, lacking potable water. Finally, some social benefits of these types of installations at remote places, even though they are expensive, are mentioned.
This study discusses the quality and quantity of energy used for cooking in Costa Rica and in the world as a whole, and then compares the advantages and limitations of solar ovens with conventional firewood and electric stoves. The payback period of a common hot box type solar oven, even if used 6–8 months a year, is around 12–14 months. Even if only 5 percent of persons facing fuel shortages in the year 2005 use solar ovens, roughly 16.8 million tons of firewood will be saved and the emission of 38.4 million tons of carbon dioxide per year will be prevented.
Dinning out on solar cookers—renewable energy 2004, An official publication of the World Renewable Energy Network
- Ss Nandwani
Nandwani SS. Dinning out on solar cookers—renewable energy 2004, An official publication of the World Renewable Energy Network (WREN/UNESCO); 2004. p. 101–4.
The science of safe water, solar cookers review
- R Metcalf
Metcalf R. The science of safe water, solar cookers review. Solar cookers international, vol. 8, CA, USA, November 2002.
Experimental study of solar oven cum water heater and solar oven cum drier-II, Published in the proceedings, II world conference on solar cookers, use and technology
- Nandwani
- Ss
- Fernandez
Nandwani SS, Otoniel Fernandez. Experimental study of solar oven cum water heater and solar oven cum drier-II, Published in the proceedings, II world conference on solar cookers, use and technology, Universidad Nacional, Herdiaa, Costa Rica, July 12–15, 1994. p. 273–84.
Solar cookers-What we are looking for?
- S S Nandwani
Experimental study of solar oven cum water heater and solar oven cum drier-II
- S S Nandwani
- Otoniel Fernandez
Dinning out on solar cookers-renewable energy 2004, An official publication of the World Renewable Energy Network (WREN/UNESCO)
- S S Nandwani
My twenty five years of experience with solar cooking-satisfaction and frustrations
- S S Nandwani