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Analysis of effecting factors on domestic refrigerators' energy consumption in use

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Abstract

In order to determine the sensitiveness of refrigerators' energy consumption on various operational factors reflecting real life conditions, four different refrigerators were tested in laboratory using Box-Behnken design with three variables (ambient temperature, thermostat setting position and additional heat load by storing warm food) at three different levels. The investigations show that the energy consumption of refrigerators is highly sensitive to actual operational conditions. Daily energy consumption of one and the same appliance may vary between a few watt-hours and 2000 Wh and even more, dependent on the respective operational factors. Analysis of variance (ANOVA) reveals that ambient temperature is the most influential factor on the energy consumption of a refrigerator. Energy use is also affected, to a minor degree, by internal compartment temperature and additional heat load. Test results are presented and energy consumption data are compared with values shown on the European Energy label. Results are discussed also with regard to the question as to whether or not the Energy Label and the associated test standard are appropriate to project actual energy consumption in use.

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... Thermo-electric refrigeration has been proven to be reliable, although, for large buildings and submarines, it is non-economic due to low COP [3]. ANOVA reveals the ambient temperature affecting the energy consumption of the appliances the most [4]. Field study on 235 refrigerating home appliances during the year 2018-2019 depicts that the sensible and latent heat load along with the demographic location of the house and the rank of appliances are responsible for higher energy consumption with energy consumption varying from 15% to 45% [5]. ...
... Fresh food compartment temperature (T ff ), ambient temperature (T a ), and heat load (Q h ) are preferred as the critical parameters. The factors are designated as ambient temperature (A), Fresh food compartment temperature (B), and heat load (C) [4,14,16]. Table 1 shows the experimental design of levels and is coded as low levels (− 1) and high levels (1). BBD is useful for identifying the individual variables and their interactions. ...
... Equation (1) represents a quadratic equation fitted to the experimental data; it is a second-order polynomial. All the linear and square terms along with the linear interactions of the factor were considered while formatting the equation [4,[24][25][26]29]. ...
Article
This paper presents the energy consumption analysis of the refrigerator and the effect of the condenser on it. According to the Bureau of Energy Efficiency (BEE), India, the energy efficiency of electric appliances is the key parameter for testing their performance before domestic use. For energy consumption analyses, the experimentation was conducted on the domestic refrigerator (165 L) top-mounted evaporator by retrofitting the refrigerator with an Elliptical Helical Coil Condenser (EHCC) and existing refrigerator with a Straight Tube Condenser (STC). Box-Behnken Design (BBD) is very significant in determining the significant factor and reducing the number of experiments. BBD has been performed to analyze the significance of factors ambient temperature, fresh food compartment temperature and the heat load in energy consumption, and the Coefficient of Performance (COP) of a refrigerator. The heat load and the ambient temperature are both very significant in determining the refrigerator's energy consumption. The most important thing is to increase the liquid content in the charge before it is supplied to the evaporator to extract more amount of heat to increase the cooling effect. The ANOVA (Analysis of Variance) results show that the ambient temperature and the heat load were more significant in increasing energy consumption and decreasing the COP and vice versa. The results of ANOVA and the experiment are very close; the R² value 0.995 precisely matches the R² adj. value 0.994. The statistical analysis using the Box-Behnken design produces a good fitting of the modeled and experimental data set. The present study aims to examine the effects of said factors and the condenser on the domestic refrigerator's energy consumption and COP. The study exhibits some enhancement in the COP to 2.59 contrary to 2.45 and energy consumption reduced to 1191 Wh from 1755 Wh during the trial of 24 h.
... Further in the reading, the authors extended their study to experimentally evaluate some of the operational factors that reflect the daily use of refrigerators such as room temperature, damper position, and the thermal load influenced by the food quantity. They concluded that the energy consumption was very sensitive to the room temperature and to a lesser extent, the refrigerator inner temperature and the thermal load [19]. Hasanuzzaman et al. [20] evaluated the usage habits in refrigerators such as the damper position and the thermal load, in addition to the room temperature and its influence on heat transfer, and the refrigerator's energy consumption. ...
... For example, Saidur et al. [14] reported that the energy consumption increases around 7.8% per each degree Celsius that the temperature is reduced in the freezer. While Geppert and Stamminger [19] concluded that the energy consumption increases with the decrease of the temperature, from 2 to 5% per each degree Celsius that the temperature is reduced in the food compartment. Similar results were found by Hasanuzzaman et al. ...
... For example, Saidur et al. [14] reported that the energy consumption increases around 7.8% per each degree Celsius that the temperature is reduced in the freezer. While Geppert and Stamminger [19] concluded that the energy consumption increases with the decrease of the temperature, from 2 to 5% per each degree Celsius that the temperature is reduced in the food compartment. Similar results were found by Hasanuzzaman et al. [20] with increases of about 46 Wh/day per each degree Celsius that the temperature decreases in the freezer. ...
Article
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This work presents the main behaviors shown in the habits of consumers of domestic refrigerators, which influences the energy consumption of this appliance. This study is based on a series of surveys answered by 200 consumers from four cities in the State of Guanajuato, Mexico. The questions were arranged with the aim of evaluating the general characteristics and usage habits such as refrigerator age, door opening frequency, damper position, load of food supplies, external and internal cleaning habits, and nearby heat sources, among other things. The randomly interviewed consumers were individuals between 20 and 60 years of age, who were interviewed using handmade surveys by experts in the field of refrigeration. In some cases, photographic evidence was gathered from the consumers’ refrigerators to represent the typical usage habits. In general, the results show that better usage habits are necessary from an energy point of view. Most consumers agree with adopting best practices for using their refrigerator.
... Different factors affect the refrigerator's energy consumption, including the following: components efficiency, ambient temperature, thermostat setting position, thermal load, frequency of door opening, and type of refrigerant [83]. Based on the Box-Behnken design, four refrigerators have been analyzed to determine the different operating factors affecting the energy consumption of domestic refrigerators. ...
... Marques et al. [83] conducted an experiment and used PCM in a copper box near the top of the compartment equipped with a heat exchanger to run through it. According to the results, the PCM can operate continuously for 3-5 h without depending on the thermal load power. ...
Article
The use of refrigerators and air conditioners has been increasing in domestic and commercial buildings constantly over the last century, resulting in a significant increase in energy demand. Thermal energy storage (TES) system may be able to reduce energy and temperature fluctuations and enhance the overall need or the performance of cooling systems. Application of phase change materials (PCMs) in TES systems can be beneficial for balancing supply and demand in energy, minimizing and shifting the peak cooling loads, reducing the temperature fluctuations. This article presents an overview of TES systems incorporating PCMs for air conditioning, refrigerators, and freezers. Literature shows different ways to incorporate PCMs in air conditioning systems. PCM use in compartments and evaporators and PCM as a heat storage medium in condensers prevail in the present review. Organic-based PCMs are the most widely used materials in air conditioning systems. Then, this study compares the applications of single and multi-PCMs in cooling systems. The results showed that, compared to a single PCM configuration, multi-PCM configurations improved heat transfer rates, reduced the gap between peak and off-peak loads of electricity demand, and shifted electricity consumption from peak to off-peak times. In conclusion, this study indicates that the potential for using PCM in refrigerators and air conditioners still requires further investigation on improving the PCMs properties and the PCM container materials and developing analytical methods for accurately predicting the PCM behavior.
... Different factors affect the function of energy consumption of domestic refrigerators. An analysis using the BoxeBehnken design on four different refrigerators has been conducted [3]. The three variables of ambient temperature, thermostat setting position, and additional heat load by storing warm food were investigated to determine different operating factors affecting energy consumption of domestic refrigerators. ...
... Low pvalue and high F-value indicate the significance of model. A P-value less than 0.05 was considered statistically significant [3]. The results of the ANOVA analysis indicate F-values of 37.26 and 47.70, Pvalues of 0.0002 and ˂ 0.0001 for reduction of energy consumption and temperature fluctuations, respectively, which confirm that the model terms are significant. ...
Article
In this study, a novel freezer consisting of an internal phase change material compartment is compared with an ordinary one. A eutectic mixture of polyethylene glycol has been used which is among the non-flammable and non-toxic phase change materials. The freezer was tested under the standard conditions in the test room both with and without phase change materials loaded in the system and all the temperatures inside the device were monitored for 24 h by the monitoring software. A design of experiment analysis was used and the main goal of this work was to use an optimum amount and temperature of eutectic phase change material inside the freezer. The application of phase change materials in the freezer compartment, located in each tray leads to a significant reduction of temperature fluctuations up to 40.59% with the optimal values of 2 kg of phase change material and melting temperature of −20 °C. Experimental results show that energy consumption of the freezer with phase change material is considerably lower than the ordinary freezer. The results of the novel freezer indicate energy savings of 8.37% with 1.5 kg of phase change material and melting temperature of −20 °C.
... Energy consumptions of domestic refrigerators are dependent on their immediate environment conditions [4] A study conducted by Björk and Palm [5] on the effect of ambient temperature on the performance of a domestic refrigeration system concluded that the optimum mass charge of the system decreases with increasing ambient temperature. Similar justifications was reported by Geppert and Stamminger [6] and a direct correlation was established between energy consumption and ambient temperature [6]. ...
... Energy consumptions of domestic refrigerators are dependent on their immediate environment conditions [4] A study conducted by Björk and Palm [5] on the effect of ambient temperature on the performance of a domestic refrigeration system concluded that the optimum mass charge of the system decreases with increasing ambient temperature. Similar justifications was reported by Geppert and Stamminger [6] and a direct correlation was established between energy consumption and ambient temperature [6]. ...
Article
Full-text available
This study presents a 40g R600a charge enhanced with various TiO 2 nano-lubricant concentrations (0 g/L and 0.2 g/L nano-lubricants) infused into an R12 domestic refrigerator tested within selected ambient temperature conditions (19, 22 and 25 °C). The performance test parameters including: energy consumption, discharge pressure, power per tonne of refrigeration (PPTR) and coefficient of performance (COP) were evaluated for the system. The results showed that infusing the nano-lubricant into the system improved the energetic performance of the system. Overall, the use of 40g at 25°C gave the best performance within the system. In conclusion, application of nanoparticles in refrigeration systems was found to improve the performances of the system even with the effect of ambient temperature. R600a-TiO 2 nano-lubricant mixture works safely and efficiently in the domestic refrigerators but requires adequate optimization.
... Key optional attributes are those allowing to model pre-defined duty cycles and to modulate (if needed) the behaviour of such cycles throughout the day. For instance, a pre-defined duty cycle may be set to reproduce the behaviour of a fridge; however, considering that actual fridge's cycles are not fixed but rather dependent on the temperature and on user's activity patterns [23,24], different duty cycles (e.g. standard, intensive, etc.) can be modelled and associated with different time frames to follow the variation of such parameters during the day (Fig. 2). ...
... As discussed in sub-section 3.1, fridges and freezers cycles are modulated within RAMP based on the main parameters influencing their behaviour, i.e. room temperature and users' activity level (as a proxy for door openings) [23,24]. Given the lack of data about indoor temperatures for the simulated building types, and considering that those are not well insulated and lack any air conditioning or space heating system, outdoor temperature is considered as approximately equal to the indoor one. ...
Article
Energy access projects in remote off-grid areas would benefit from the adoption of a multi-energy system perspective, addressing all energy needs - not only lighting and power appliances, but also waterheating and cooking - by means of a mix of energy vectors. However, multi-energy analyses in remote areas are hindered by a lack of models allowing for the generation of multi-energy load profiles based on interview-based information characterised by high uncertainty. This study proposes a novel open-source bottom-up stochastic model specifically conceived for the generation of multi-energy loads for systems located in remote areas. The model is tested and validated against data obtained from a real system, showing a very good approximation of measured profiles, with percentage errors consistently below 2% for all the selected indicators, and an improved accuracy compared to existing approaches. In particular, some innovative features - such as the possibility to define and modulate throughout the day appliances’ duty cycles - seem to be determinant in marking a difference with previous approaches. This might arguably be even more beneficial for case studies characterised by a larger penetration of appliances that are subject to complex and unpredictable duty cycle behaviour
... Later, the authors extended their study to experimentally evaluate some of the operational factors that reflect the daily use of refrigerators such as the ambient temperature, the position of the thermostat, and the thermal load influenced by the amount of food. They concluded that the energy consumption is very sensitive to the ambient temperature and, to a lesser extent, the internal temperature of the refrigerator and the thermal load [17]. On the other hand, James et al. ...
... Figure 6a corresponds to a room temperature of 20 • C, and Figure 6b corresponds to a temperature of 25 • C. In both figures, it is clearly evident that the power input of the first on-state was linked to the amount of food stored in the refrigerator. Some studies mentioned that the additional energy consumption originated during the food-cooling stage [17]. This cooling stage is particularly evident during the first on-state of the compressor. ...
Article
Full-text available
This study seeks to understand the thermal and energetic behavior of a domestic refrigerator more widely by experimentally evaluating the main effects of the thermal load (food) and the variation of the ambient temperature. To carry out the experiments, the thermal load was classified based on the results of a survey conducted on different consumers in the state of Guanajuato, Mexico. The thermal behavior of both compartments of the refrigerator, the total energy consumption, the power of the compressor in its first on-state, and the coefficient of performance, according to the classification of the thermal loads and the room temperature, were evaluated. Finally, it is verified that the thermal load and the room temperature have a significant influence on the energy performance of the refrigerator.
... A number of early authors have examined the energy consumption of refrigerators in test laboratories, and many of these have established that room air temperature is a key driver of the energy consumption (Alissi et al. 1988; Goodson and Bullard 1994;Grimes et al. 1977;Masjuki et al. 2000;Meier and Heinemeier 1988). This has been confirmed in more recent studies, which all generally conclude that room air temperature in which the appliance operates is the most important factor that impacts on energy consumption in conditions of normal use (Anjana et al. 2015;Björk and Palm 2006;Geppert and Stamminger 2013;Saidur et al. 2002;Saidur et al. 2006;Saidur et al. 2008). Many of these authors also examined the impact of user interactions such as door openings. ...
... Refrigeration appliance response to room air temperature While it is well known and understood that the room air temperature will have a significant impact on the energy consumption of a refrigerating appliance, there is surprisingly little data in the public domain on this topic. A range of authors have examined the temperature response of a handful of refrigerator models in the test laboratory setting (Alissi et al. 1988;Anjana et al. 2015;Geppert and Stamminger 2013;Grimes et al. 1977;Koa and Kelly 1996;Saidur et al. 2002), but these authors have not established any generalised response in energy to changes in room air temperature. One of the major issues is that, until recently, most regional test procedures have only tested energy consumption at a single ambient temperature so data across different temperatures have not been routinely collected. ...
Article
Full-text available
There is little concrete understanding of the energy consumption of refrigerating appliances during normal use or the main influences on their energy consumption. To date, no widely accepted method to disaggregate measured energy consumption measured in the home into its key components has been demonstrated. This paper examines the main external factors that impact on the energy consumption of existing refrigerating appliances in the home and how they respond to changing conditions, namely: room air temperature, defrosting behaviour and user interactions. Analysis of field data from 235 homes in Australia demonstrates that room air temperature is by far the largest factor accounting for typically around 75% of total energy consumption. Where present, energy used for defrosting is relatively small at around 10%, but this does vary by household and the type of defrost controller. User interactions typically account for 15% of total energy consumed by main household refrigerating appliances, but this varies from a few percent to as much as 45% in large households. The method set out in this paper provides a basis for more in depth analysis and a better understanding of energy consumption of household refrigerators in different regions.
... Results showed that ambient temperature had a significant correlation with energy consumption. However, the refrigerator performance is sensitive to consumer behavior and conditions in private homes [84]. ...
Article
Full-text available
The use of refrigerators and air conditioners has been increasing in domestic and commercial buildings constantly over the last century, resulting in a significant increase in energy demand. Thermal energy storage (TES) system may be able to reduce energy and temperature fluctuations and enhance the overall need or the performance of cooling systems. Application of phase change materials (PCMs) in TES systems can be beneficial for balancing supply and demand in energy, minimizing and shifting the peak cooling loads, reducing the temperature fluctuations. This article presents an overview of TES systems incorporating PCMs for air conditioning, refrigerators, and freezers. Literature shows different ways to incorporate PCMs in air conditioning systems. PCM use in compartments and evaporators and PCM as a heat storage medium in condensers prevail in the present review. Organic-based PCMs are the most widely used materials in air conditioning systems. Then, this study compares the applications of single and multi-PCMs in cooling systems. The results showed that, compared to a single PCM configuration, multi-PCM configurations improved heat transfer rates, reduced the gap between peak and off-peak loads of electricity demand, and shifted electricity consumption from peak to off-peak times. In conclusion, this study indicates that the potential for using PCM in refrigerators and air conditioners still requires further investigation on improving the PCMs properties and the PCM container materials and developing analytical methods for accurately predicting the PCM behavior.
... Having a higher F-value makes a lower P-value and represents the significance of the model. P-value less than 0.005 reflects statistically significant [66,67]. An F-value and P-value were used to evaluate the statistical significance of the equation. ...
Article
In this paper, we presented a simple method of preparation, characterization and thermo physical properties of phase change materials with nanoparticles. The study began with the preparation of NaNO3/diatomite phase change materials (PCMs) and with adding Nano expanded graphite and Nano diamond additives as a thermal conductivity enhancer for high temperature applications. The composite phase change materials are successfully synthesized using a two-step mixing and sintering method for high temperature applications such as concentrated solar powers and solar reactors. In the following, by using the design of experiment (DOE), two responses (phase change temperature and phase change time stability) were investigated in shape stable composite in phase change materials (SS-CPCM) with and without nanoparticles. DSC and IR-Camera results were used as responses and thermal properties of the SS-CPCM. Economical SS-CPCM was prepared, characterized, and optimized by DOE software. Experimental analysis, including 20 runs, has been taken using a design of experiment, and the optimum run has been selected. The optimum SS-CPCM has a latent heat of 87.32 J/g and a melting temperature of 304.64 °C. In the solidification cycle, it requires 87.32 J/g heat dissipation to phase change and solidify at 302.03 °C. A weight loss of 0.00619 g after 50 cycles of phase change for NaNO3/Diatomite/Nano EG SS-PCM shows a reliable SS-CPCM. The same optimum pellet with only a different Nano material of Nano diamond has a latent heat of 91.02 J/g and a melting temperature of 304.98 °C. In the solidification cycle, it requires 90.51 J/g heat dissipation to phase change and solidify at 302.14 °C.
... Los resultados muestran un aumento del 59% con una tendencia casi lineal. En [7] se presenta un estudio en un refrigerador doméstico considerando una carga térmica adicional en el interior del gabinete. Se reporta un consumo de energía adicional del 0.04% durante el proceso de enfriamiento por primera vez al alcanzar la temperatura deseada. ...
Conference Paper
Full-text available
El consumo de energía eléctrica por refrigeración comercial ligera, ha ido en aumento durante las últimas décadas debido al crecimiento de los mercados. Las características de operación para este sector son particulares y han recibido poca atención a nivel científico. En este trabajo se hace un estudio experimental del efecto que tiene la carga interior de gabinete en el desempeño de un refrigerador vertical de vitrina, basado en la Relación de Eficiencia Energética (EER). Primero se determina la carga adecuada de refrigerante R134a para tres niveles de temperatura ambiente 24, 32 y 40°C, la cual se observó de 175g. Los resultados muestran una reducción en el consumo de energía eléctrica del orden del 2% para una carga de gabinete de 100 l respecto a su condición sin carga. La EER es mayor cuando la carga de gabinete es de 60 l para las temperaturas ambiente de 24 y 32°C. Para la temperatura ambiente de 40°C, la EER es mayor cuando el refrigerador se encuentra sin carga de gabinete. Los cambios más importantes en la EER se deben a la temperatura ambiente y no a la carga de gabinete. Palabras Clave: refrigeración comercial ligera, carga interior de gabinete, EER, R134a, Refrigerador vertical de vitrina. A B S T R A C T Electric energy consumption in commercial light refrigeration, has been growing during last decades due to the markets growth. The refrigerator operation characteristics are particular for this sector and have scientifically received little attention. In this work the importance of the cabinet load on the performance, on a vertical display refrigerator based on the Energy Efficiency Ratio (EER), is experimentally studied. First the refrigerant R134a charge for three ambient temperatures of 24, 32 and 40°C is determined in 175 g. The results show a reduction in the electric energy consumption of 2% for the cabinet load of 100 l is observed. The EER resulted higher for a cabinet load of 60 l for ambient temperatures of 24 and 32°C. For 40°C the EER is higher without cabinet load. The largest changes in EER are due to ambient temperature rather than to cabinet load.
... The door opening causes a sudden thermal load added to the refrigerator because of the air transfer to the compartment. Therefore, the refrigerator should operate longer to overcome this load, and that leads to an increase in energy consumption (Geppert & Stamminger, 2013). The application of PCM in the compartmental space can reduce this extra thermal load. ...
Article
This paper reviews and discusses various studies on the application of phase change materials (PCMs) with domestic refrigerators and freezers regarding thermal management and performance enhancement. Covered previous studies in this review indicate the potential of PCMs in improving COP and exergy efficiency of refrigeration systems, in addition to reducing energy consumption, CO2 emissions and compartment temperature fluctuation. The paper also presents the effect of PCM performance under different thermal loads including phase change temperature, ambient temperature, evaporation temperature, door opening, defrosting and power failure. The effect of PCM's configuration, geometry, orientation and location on the performance of refrigeration systems, are also discussed. The literature review concludes that many researches have concentrated on the incorporation of PCM at the evaporator and compartment, while few studies have been carried out at the condenser section. The most common PCMs used in domestic refrigeration systems are water and eutectic PCMs solutions. We conclude that eutectic PCMs demonstrate better system performance than water.
... It is also equally important to find the sources of energy consumption for the refrigerator. There are several factors involved, which can influence the performance of refrigerators, i.e., design of various components such as compressor [6][7][8], evaporator [9][10][11], condenser [12] and capillary tube [13], type and quantity of refrigerant [14,15], type of insulation in the refrigerator [16], door openings [17,18], and ambient temperature [19]. Among all the factors, many of the researchers reported ambient temperature as the most prominent source of power consumption for the refrigerator [20][21][22][23][24][25]. ...
Article
Energy consumption of a household refrigerator majorly depends upon the ambient temperature and is highest at the noontime, while lowest at the night. In order to mitigate the impact of higher ambient, condenser of the refrigerator is modified by incorporating phase change material in it. This paper presents development of numerical model of the PCM based condenser and its comparison with the experimental model. A 3D numerical model for a PCM, namely, FS21 based condenser has been developed in commercial software ANSYS FLUENT 16.2 and the simulation outcome are compared with the experimental test results. A correlation of a coefficient of performance (COP) which is a function of PCM temperature has been proposed. Based on the developed numerical model and the correlation, two other PCMs, RT25 and RT25HC, based heat exchangers are also analyzed numerically and their PCM temperatures are predicted. At the end, COP of the refrigerator with each PCM is compared.
... Thawing food in a refrigerator reduced energy consumption by 26%. Geppert and Stamminger [38] tested four different appliances from the same manufacturer in the laboratory as a function of three independent variables at the same time. In the tests they varied ambient temperature, internal compartment temperature and heat load by adding warm food into the appliance. ...
Article
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Energy used by domestic refrigerators can be a large part of household energy use. In most countries, consumers are informed of the energy used by their appliance through energy labels or manufacturers data provided with the appliance. Work was carried out to ascertain whether the information provided to consumers provided an accurate reflection on the energy used in real life. Data was extracted from a large-scale survey of the performance of domestic cold appliances. Information on temperature control and electricity consumption as well as information about the appliances was collected in the survey. In total 998 appliances were examined, of which 124 were used for the analysis in this paper. For each of these appliances, the electricity measured by the appliance manufacturer in a test laboratory was compared to the energy consumed in the home. Sixty-one percent of appliances consumed more energy in the home than the laboratory. The rank order of energy used by appliances was also assessed and found to vary considerably between the laboratory and the home. A more transparent test method to assess performance of refrigerated appliances in the home is suggested.
... Manufacturers of domestic refrigerators expect them to function optimally irrespective of their climate condition and enclosed or ambient operation temperature. It was concluded in the work of Geppert & Stamminger [3] that ambient temperature of domestic refrigerators is the influential factor on their energy consumption. Besides, the need to reduce energy consumptions of domestic refrigerators is crucial because it crux to their direct emissions. ...
Article
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The effect of ambient temperatures (19, 21, 23 and 25 °C) on energetic performance of an R134a domestic refrigerator retrofitted with varied mass charges (40, 50, 60 and 70g) of R600a and LPG (60/40 Propane-butane mixture) refrigerants was studied. The R134a domestic refrigerator was slightly modified with valves and integrated with appropriate pressure gauges, digital thermocouples and a watt meter to monitor the pressures, temperatures and the energy consumptions of the refrigerants within the system in the ambient conditions. Performance test investigated at steady state were pressure ratio, energy consumption, discharge and cabinet temperatures respectively. In conclusion, results showed that the retrofitted hydrocarbon refrigerants could be suitable replacements in all regards, provided adequate optimization is done.
... Properties of some hydrocarbon refrigerants used in refrigeration systems in comparison to conventional refrigerant like R12, R134a are as shown in Table 1 International In addition, hydrocarbon-based refrigerants are expected to work efficiently irrespective of the surrounding ambient temperature condition of their refrigeration system. In the study concluded by Geppert and Stamminger [10], it was concluded that domestic refrigerators are expected to function in all ambient conditions. Authors therefore experimentally investigate the effect of varying ambient temperature condition in an R134a refrigerator retrofitted with R600a and LPG refrigerants. ...
Article
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In this work, a slightly modified 100g R134a domestic refrigerator was retrofitted with limited mass charge (30g) of R600a and LPG refrigerants and tested in different ambient temperature conditions (19, 21, 23 and 25 °C). The test rig was fitted with appropriate instrumentation for experimentation. Performance characteristics investigated with the test rig at steady state include evaporator air temperature, discharge temperature and power consumption. Results showed that the retrofitted hydrocarbon refrigerants in the system at the ambient conditions gave power consumption, discharge temperature, condensing pressure lower by 15 – 45 %, 16 – 30 % and 25 – 62 % than R134a refrigerant. In addition, the cabinet temperature of the system with the hydrocarbon refrigerants were higher than R134a by 10 - 60 %. In conclusion, the investigated energetic characteristics of the system improved with reducing ambient temperature and all conditions with infused hydrocarbon refrigerants attained cabinet temperatures lower than -3 °C in accordance to ISO 8187 recommendation for domestic refrigerators.
... For consistency, the ambient temperature is controlled to be within the range 23 • C ± 1 • C since it is known that this can have a significant influence on energy consumption [28,29]. ...
Article
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The rapid proliferation of the ‘Internet of Things’ (IoT) now affords the opportunity to schedule the operation of widely distributed domestic refrigerator and freezers to collectively improve energy efficiency and reduce peak power consumption on the electrical grid. To accomplish this, the paper proposes the real-time estimation of the thermal mass of each refrigerator in a network using on-line parameter identification, and the co-ordinated (ON-OFF) scheduling of the refrigerator compressors to maintain their respective temperatures within specified hysteresis bands commensurate with accommodating food safety standards. A custom model predictive control (MPC) scheme is devised using binary quadratic programming to realize the scheduling methodology which is implemented through IoT hardware (based on a NodeMCU). Benefits afforded by the proposed scheme are investigated through experimental trials which show that the co-ordinated operation of domestic refrigerators can i) reduce the peak power consumption as seen from the perspective of the electrical power grid (i.e., peak load levelling), ii) can adaptively control the temperature hysteresis band of individual refrigerators to increase operational efficiency, and iii) contribute to a widely distributed aggregated load shed for demand side response purposes in order to aid grid stability. Importantly, the number of compressor starts per hour for each refrigerator is also bounded as an inherent design feature of the algorithm so as not to operationally overstress the compressors and reduce their lifetime. Experimental trials show that such co-ordinated operation of refrigerators can reduce energy consumption by ~30% whilst also providing peak load levelling, thereby affording benefits to both individual consumers as well as electrical network suppliers.
... A slightly rising incline can be observed for baseload in all the three patterns. This incline can be interpreted physically as being caused by refrigeratorfreezers, as the energy consumption of refrigerator-freezers could increase slightly with the ambient temperature [27]. The blue squares indicate outliers which deviate significantly from baseload. ...
... The minimum temperature fluctuation of the fresh food compartment has the potential to be further reduced if the precision of the temperature controller is able to be improved. Anyway, the temperature control accuracy of 0.4°C is already much higher than that of a traditional household refrigerator (normally larger than 3.0°C) [35]. The aforementioned results demonstrate the precise temperature management potential of CLT in the field of refrigerators. ...
... On the other hand, use conditions in every household (number and time length of door openings, food and beverage load, internal temperature settings) and the seasonality of ambient conditions will also affect energy consumption [103]. Regardless of the refrigerator type tested, Geppert and Stamminger [35] showed that ambient temperature is the main factor affecting energy consumption, while the internal set temperature and refrigerator load had a minor effect. Some of the standards listed in Table 2 include the effect of the load on the energy consumption but the food thermalload emulation is based on water-filled PET bottles or icecube trays, and if test packages are used, they are just cellulose gel bricks with a caloric thermal load similar to meat. ...
Article
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This article overviews the technological evolution of residential refrigerators, key national and international regulations covering them, and summarizes the information available to estimate the quality and safety deterioration in foods and beverages stored in them. At present, the national and international government standardized performance tests used to assess residential refrigerators focus on energy consumption. Efforts by refrigerator manufacturers to consider the impact of temperature fluctuation, temperature recovery, extreme ambient temperature, door openings, and other factors affecting temperature control and, thus, food safety and quality need to be harmonized, validated, and implemented as official standardized tests. Published predictive models here summarized, and describing microbial growth and other product degradation mechanisms, could be combined with energy efficiency evaluations in future science-based regulations seeking a balance between energy consumption and food preservation. While numerous mathematical models are available, this review identified a serious lack of model parameter values to allow a combined assessment of energy consumption and food preservation in residential refrigerators. Much of past research has focused on temperature abuse effects and, thus, not applicable to estimating food preservation under the prevailing temperatures in residential refrigerators. Particularly urgent is the data on the microorganisms’ response at multiple temperature levels, allowing the development of secondary models to assess the temperature effect on the safety and quality of a diverse but representative pool of products. New standardized testing procedures could then be developed to guide the design of new residential refrigerators minimizing food waste and the frequency of foodborne diseases while meeting energy consumption requirements.
... Hal ini disebabkan lemari pendingin termasuk penyumbang pemakai energi listrik yang paling besar di rumah tangga, terutama untuk golongan tarif R1-450VA, R1-900VA dan R1-1300VA (BPPT, 2012), bahkan secara umum diperkirakan mencapai 10% dari total energi listrik yang diproduksi di seluruh dunia (Melo & Silva, 2010) serta menyebabkan emisi gas rumah kaca tahunan sebesar 450 juta ton CO2eq (Ouali dkk, 2016). Besarnya kontribusi ini dikarenakan lemari pendingin merupakan piranti yang sudah umum digunakan di dalam rumah tangga dan dalam pemakaiannya terus terhubung dengan sumber daya (Geppert, 2013). Selain itu, piranti inipun dilaporkan memiliki efisiensi termodinamika yang rendah, dengan nilai yang tidak lebih tinggi dari 20% (COPActual / COPCarnot) (Hermes & Melo, 2008). ...
Article
Full-text available
p>Perhitungan konsumsi energi suatu piranti kelistrikan rumah tangga diperlukan sebagai dasar penentuan taraf/level bintang untuk labelisasi energi produk tersebut. Pada produk emari pendingin (kulkas), perhitungan konsumsi energi dilakukan pada saat daya dan temperatur sudah mencapai kondisi tunak ( steady state ). Berdasarkan IEC 62552:2015, terdapat dua pendekatan untuk menentukan kondisi tunak, yaitu pendekatan SS1 dan SS2. Makalah ini mengkaji perbandingan hasil antara kedua pendekatan tersebut dengan menggunakan data pengukuran daya dan temperatur dari suatu lemari pendingin dua pintu. Hasil kajian menunjukkan bahwa daya dan temperatur kondisi tunak yang didapatkan dengan menggunakan pendekatan SS1 tidak berbeda jauh dengan yang menggunakan pendekatan SS2. Kata kunci : konsumsi energi, lemari pendingin, IEC 62552:2015, pendekatan SS1, pendekatan SS2</p
... The cold loss of the topside freezer was reused by the CLTs and the heat-conducting plates; this part of cold energy was transferred to cool the fresh food compartment. The temperature management precision of the fresh food compartment was improved since the on/off cycle of the CLTs can be reduced to 2 −5 min, much lower than that of the refrigerating cycle, which was around 20 −50 min ( Geppert et al., 2013;Hassan et al., 2015 ). The original evaporator of the fresh food compartment was removed, and cold energy was only provided by the refrigerating cycle to the freezer. ...
Article
The refrigerator is one of the most essential domestic appliances and causes considerable energy consumption every year. The efficiency of a normal household refrigerator is significantly affected by the heat-insulating property of the thermal barrier of the freezer due to its low inner temperature. In this study, a novel refrigerator with a loop thermosyphon is put forward to decrease the heat transfer between the freezer and ambient air. It has great potential to be popularized as a sustainable energy technology or applied in the renewable energy field considering its significant energy-saving effect, simple structure, and low cost. The energy-saving behavior of the refrigerator is preliminarily evaluated based on the theoretical calculation. The temperatures of ambient, the fresh food compartment, and the location of the heat transport component are varied; the impacts are analyzed. The total cold loss of the topside and side freezer walls is reduced from 16 W to 14 W in the normal test conditions, and the energy-saving ratio varies from 6.3% to 28.5% when the ambient temperature, the location of the heat transport component, and the fresh food compartment temperature vary. The results certificate the energy-saving capability of the novel refrigerator and its reliability in hot climate.
... For water-based systems such as food, freezing is a much more energy intensive process than simple cooling-the energy required to freeze a unit mass of water (the latent heat of fusion) is nearly 100 times that required to cool the same unit mass one degree Centigrade. Thus freezers experiencing frequent additions of unfrozen mass, such as those used during industrial food processing, experience lower efficiencies than those used in domestic contexts (Geppert and Stamminger, 2013;Hasanuzzaman et al., 2009). The storage efficiency is characterized by the energy required to hold a mass of food at a desired subfreezing temperature over long periods, both at permanent storage sites and during transportation, and in the face of controlled and uncontrolled ambient temperature fluctuations. ...
... Some of these factors focus on the use of consumer habits [19]. In this regard, the ambient temperature represents the higher effect on energy consumption [20], [21]. For instance, in an experimental study, it was possible to reduce the energy consumption of a domestic refrigerator through an adaptive method for defrosting [22], which involved parameters as door opening and the compressor operation mode. ...
Article
In this work, a domestic refrigerator was tested to determine the power consumption for different positions of the shelves. The main contribution of this study is the application of several strategies to analyze and model the power consumption of a domestic refrigerator when the fresh food shelves are changed of position. First, computer simulations were performed to analyze the power consumption using: the moving average, the numerical derivative and the Fourier transform. These simulations were used to study: changes, periodic behaviors, minimum, maximum and average values for the power consumption. Second, prediction methods were used to model the power consumption, these methods include: cubic splines, the bilinear method and artificial neural networks. With these methods, 2D color graphs were built to predict the power consumption for any shelves positions. The validation results revealed that the cubic spline method provides the best results. Finally, it can be concluded that the models proposed in this work provide new insights that can be used to design the internal compartments of the fresh food in order to try reducing the energy consumption.
... Sarhadian, (2004) which deteriorates the quality of the food (James and James, 2010). Geppert and Stamminger (2013) conducted experiments on four different refrigerators in laboratory to detersmine the sensitiveness of refrigerators' by varying the ambient temperature, thermostat setting position and heat load. Based on their analysis of variance (ANOVA), they noticed that the ambient temperature is the most influential factor on the energy consumption of a refrigerator. ...
... Early research into refrigerator energy consumption identified that ambient temperature was a key driver of energy consumption [8][9][10][11][12]. This has been confirmed in many recent studies, which conclude that room temperature in which the appliance operates is the most important factor that impacts on energy consumption in conditions of normal use [13][14][15][16][17][18][19][20]. The main research question to be addressed is how can the changes in energy consumption of refrigerating appliances that are likely to be experienced under conditions of normal use be estimated from existing data sets and measurements without the need for extensive testing and complex additional measurements. ...
Article
Refrigerators are a common appliance in developed and emerging economies around the world. These appliances consume significant energy globally and improving their efficiency is an important aspect of future climate change mitigation. It is widely understood that the energy consumption of household refrigerating appliances is strongly influenced by room temperature and many analysts have identified ambient temperature as the most important factor in normal use. Room temperature has two main effects on the energy consumption of refrigerating appliances. Firstly, the temperature difference between the compartment and the room dictates the heat gain into the appliance through the wall insulation and door seals. A second effect is that a change in room temperature affects the condensing temperature. An increase in room temperature reduces overall refrigeration system efficiency by increasing the difference between the evaporating and condensing temperature. This paper examines laboratory data for 111 appliances where energy consumption is measured at four ambient temperatures from 10 °C to 40 °C. Field data for 235 appliances in homes is also examined. This is more complex to analyse, but it does provide useful information on underlying energy changes due to changes in room temperature during normal use. This paper determines the ratio of energy at 16–32 °C (energy conditions in IEC62552-3) and explores the shape of the energy curve at intermediate temperatures in order to develop a generalised energy curve as a function of temperature for the refrigerating appliances measured. The field data gave highly comparable shape data to that measured in the laboratory. The results provide a useful method to estimate the likely power consumption of different appliance types under a wide range of operating conditions, even where limited data is available.
... This set of studies shows the thermal behaviour of domestic refrigeration equipment in various countries over the years, concluding that there is a significant share of refrigerators in the world operating at temperature higher than the recommended, regardless of the technological evolution and informative campaigns about food safety. To determine the sensitivity of the energy consumption of refrigerators to various operational factors that reflect actual operating conditions, four different refrigerators were tested using the experimental design method Box-Behnken with three variables (room temperature, thermostat setting position and additional thermal load for hot food storage) [11]. Results show that the energy consumption of refrigerators is highly sensitive to real-life situations (variations up to 2 kWh). ...
Conference Paper
Food safety and quality as well as storage conditions leading to food waste are related to the reduced thermal performance of domestic refrigerators, the mismanagement of food stored in it or the misuse of the equipment. This paper analyses the operative conditions of refrigerators in the student community of the University of Beira Interior (Covilhã, Portugal). A test sample of 51 appliances in the student households was instrumented with temperature dataloggers. Simultaneously, surveys on the use of refrigerator and food waste were applied to the students, ultimate users of the appliances. The students, with an average of 23 years old, mostly female (65.9%), live alone (6%), with their parents (24%), or with other students (71%). The test sample of appliances had, on average, a nominal electrical power of 126 W and an inner volume of 205 liters. It was found that the average storage temperature was 5.5ºC. The storage temperature in the appliances increased with the number of people who used it. This figure was largely due to improper use behaviour, in particular the number of times that the refrigerator door was open unnecessarily. The joint analysis of these data allows relating the use behaviour of with food waste. The comparison with similar studies conducted in the past shows that the average storage temperature in the current study is lower, mainly due to the technological evolution of appliances as well as the global awareness concerning food safety and food waste. The results of this work, apart from offering results about the performance of the operative conditions of refrigerators in a community not studied so far, highlights the need for further awareness of good practices to reduce food waste and simultaneously ensure food safety of the perishable food products stored in domestic refrigerators. These results could be extrapolated to the remaining people in order to develop strategies to improve cities sustainability.
... Alongside the efficiency ratings under test conditions, the energy performance of cold storage appliances is also highly sensitive to how they are used and the circumstances they are used in. Factors including the ambient temperature in the room, the chosen internal thermostat setting, the temperature of items placed in the appliance and the opening of doors all impact on energy consumption (Geppert and Stamminger, 2013). Users are advised to locate fridges and freezers away from other heat sources, keep them set to recommended temperatures, allow hot food to cool before placing inside, and keep door opening to a minimum (Energy Saving Trust, n.d.). ...
Research
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This report introduces a new approach to understanding the role of everyday household practices in domestic resource consumption and addressing the policy challenges this presents. To demonstrate this ‘change points’ approach we focus on one such topic: tackling energy use in the provision of food at home. Providing food in the home uses large quantities of energy, with 30-40% of the evening peak in electricity demand in the UK accounted for by food practices. In light of societal concerns over energy, reducing total energy use in domestic food provisioning, or shifting that energy use away from peak electricity demand, are worthwhile objectives.
... Given the prevalence of the use of refrigerators, the two stated refrigerator parameters are important factors within their base designs and possible improvements of their thermal performances [6]. Some researchers have proven that the consumption of energy in refrigerators is dominantly affected by real, operational circumstances, and the same equipment's daily energy consumption levels can differ [7,8]. Thus, measuring the electrical parameters precisely has become more important. ...
Article
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Refrigerators are one of the main devices used in our daily lives, and they play important roles in storing food and maintaining its freshness. Refrigerator manufacturing is improving day by day and it is important for the appliance to present a diverse array of functions to its users, since usage requirements vary from region to region. For this purpose, refrigerators must pass through various performance tests like an energy efficiency test while they are produced in factories. Factories have designated testing rooms for these performance tests. After the products' release, technical services and customers do not have such a luxury of pretesting the machines. In this study, a portable performance-testing device was designed specifically for household refrigerators. Experimental analyses were based on the TS EN 15 502 standards, which are compatible with the IEC 62552 standards. The test series consisted of temperature, current, voltage, and humidity measurements. The control results were indicated by an Arduino-based microprocessor. The tests could be controlled by the users in real time via an LCD panel on top of the indicated testing device. The monitor showed the relevant interface programs written in C# and a web interface. Moreover, the developed setup could determine the energy efficiency class of refrigerators, among their other qualities.
... In general, the energy consumption of refrigerator depends upon the design of evaporator, condenser, and compressor, thermostat setting, the frequency of refrigerator door openings, ambient temperature, thermal load, the material used for thermal insulation and refrigerant type. [2][3][4][5][6][7][8] Geppert and Stamminger 9 showed by analysis of variance (ANOVA) that the ambient temperature is the most in°uential factor on the energy consumption of a refrigerator. Various researchers studied the e®ect of ambient temperature on the energy consumption of refrigerator. ...
Article
Tropical countries like India, the ambient temperature reaches to 45–50(Formula presented.)C in the summer and higher ambient temperature directly impacts the energy required by the household refrigerator. This paper presents an experimental performance of a domestic refrigerator incorporated with a phase change material (PCM)-based condenser in parallel to the conventional wire-and-tube air-cooled condenser for the climatic conditions of India. It is proposed to operate the refrigerator with the PCM-based condenser, while the ambient temperature is higher during the day, otherwise with the air-cooled condenser. Due to large latent heat storage capacity of the PCM, the condenser temperature would not increase significantly. The COP of the PCM-based condenser was 28% higher as compared to air cooled condenser for 60(Formula presented.)min which reduce to 3% as PCM temperature reached to 33(Formula presented.)C. The energy consumption is lower by (Formula presented.)% in (Formula presented.)(Formula presented.)h of refrigerator experimentation with the proposed modification.
... Consequently, many new projects are supported by policy makers and researchers in order to improve the energy efficiency [2], to intensify the energy production from renewable resources and reduce the greenhouse gas emissions [3]. In the residential sector the energy efficiency and savings is gaining more and more importance, enthused either by economic concerns or environmental reasons [4]. ...
Article
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A vital element in making a sustainable world is correctly managing the energy in the domestic sector. Thus, this sector evidently stands as a key one for to be addressed in terms of climate change goals. Increasingly, people are aware of electricity savings by turning off the equipment that is not been used, or connect electrical loads just outside the on-peak hours. However, these few efforts are not enough to reduce the global energy consumption, which is increasing. Much of the reduction was due to technological improvements, however with the advancing of the years new types of control arise. Domestic appliances with the purpose of heating and cooling rely on thermostatic regulation technique. The study in this paper is focused on the subject of an alternative power management control for home appliances that require thermal regulation. In this paper a Model Predictive Control scheme is assessed and its performance studied and compared to the thermostat with the aim of minimizing the cooling energy consumption through the minimization of the energy cost while satisfying the adequate temperature range for the human comfort. In addition, the Model Predictive Control problem formulation is explored through tuning weights with the aim of reducing energetic consumption and cost. For this purpose, the typical consumption of a 24 h period of a summer day was simulated a three-level tariff scheme was used. The new contribution of the proposal is a modulation scheme of a two-level Model Predictive Control's control signal as an interface block between the Model Predictive Control output and the domestic appliance that functions as a two-state power switch, thus reducing the Model Predictive Control implementation costs in home appliances with thermal regulation requirements.
... In the residential buildings, cooling appliances like refrigerators and freezers consume more energy as they are connected with the grid for 24 h [7]. In China, 22.2% of additional electrical energy is consumed by the household with refrigerator when compared to the household without refrigerator [8]. ...
Article
Residential buildings contribute to the greenhouse gas emissions through the use of energy-intensive products. Household energy consumption and associated emissions can be reduced partly if energy-saving methods are adopted by the occupants. This paper studies the performance of domestic refrigeration system with water-cooled condenser in which the water used for general purposes in a residential building has been considered as the cooling water for the condenser. The circulation quantity of water per day has been varied, and the variation of COP has been studied and presented. The results obtained from the theoretical and experimental studies show that the COP of the system with brazed plate heat exchanger (BPHE) as water-cooled condenser is 57% to 75% higher than that of air-cooled condenser. Moreover, the system with water-cooled BPHE reduces the per day energy consumption of the system from 21% to 27%. The TEWI of the system with water-cooled BPHE is also 5% to 43% lower than that of the system with air-cooled condenser, and thus the building energy-efficiency could be improved by integrating the refrigerator with the general water supply of a residential building.
... Numerous factors have been found to affect the energy consumption of individual refrigerators. These include room temperature, position close to sources of heat, frequency of door opening, and thermostat setting (ranked in order of importance according to Saidur and others 2002and Geppert and Stamminger 2013. These factors are, of course, also important with respect to temperature control. ...
Article
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The domestic refrigerator is now a common household device with very few households in the developed world not possessing one, or more, for the storage of chilled foods. Domestic storage is the last, and in many respects the most important, link in the food chill chain. Inadequate domestic refrigeration or cooling is frequently cited as a factor in incidents of food poisoning. The authors reviewed the temperature performance of refrigerators in 2008. This new review builds on that review, covering studies that have been published since (and those that were unfortunately missed in the first review), and also seeks to put this important stage of the food cold chain in its context. It is clear from the published data that many refrigerators throughout the world are running at higher than recommended temperatures. It is also clear that, despite improvements in energy use, the temperature performance and use of refrigerators has not changed significantly in the last 40 or so years. Many consumers still remain unaware of the recommended refrigeration temperature range, how to ensure that the correct refrigeration temperature range is achieved, the importance of monitoring that the recommended temperature range is being maintained, and the potential hazards of temperature abuse.
... Domestic refrigerator is one of the major energy-consuming devices [1], and about 15 % of the worldwide energy is consumed by refrigeration systems, as it is common in every household besides being connected to power supply & S. Joseph Sekhar josephsekhar@sxcce.edu.in continuously [2,3]. India occupies the fourth place among the highest energy-consuming nations in the world, and its energy consumption increases 4 per cent every year [4,5]. ...
Article
Domestic refrigeration system is one of the major energy-consuming devices. Improving its energy and exergy efficiencies plays a vital role in the energy conservation strategies on domestic energy sector. One of the methods to improve the performance is the replacement of existing components and operation of the system in low condensing pressure. Therefore, in this work, the conventional air-cooled condenser has been replaced with water-cooled brazed plate heat exchanger. Besides the COP, exergy efficiency and irreversibility in all the basic components of a 190-L domestic refrigerator have been studied. The experimental results show that the COP and exergy efficiency of the proposed system are 52–68 and 46–55 %, respectively. This is higher than that of the conventional system. Moreover, the irreversibility of the proposed system is 34 % less than that of the conventional system, and the exergy efficiency of HC mixture is 4–7 % higher than R134a under similar operating conditions.
Article
In the present study, an attempt has been made to carry out an experimental investigation on the variations in the performance of vapor compression refrigeration system (VCRS) with the application of magnetic configurations. Magnetic configurations used for the present work were pair of magnets (MC-1) and Halbach array (MC-2) with the magnetic field intensities of 3000 and 7200 Gauss, respectively. The coefficient of performance (COP) was first determined in the absence of a magnetic field and then with the application of magnetic configurations on the condenser liquid line. Experimental outcomes show that the performance of the VCRS is dependent on the magnetic field strength and the magnetization time for the given conditions. Under the same conditions, the COP of the system increased up to 8.38% for MC-1 using two magnetizers and 9.94% for MC-2 using one magnetizer. Finally, it was observed that the TEWI analysis for the MC-1 and MC-2 was lesser than the conventional system, which was in the range of 0.72–2.11% and 1.83–3.39%, respectively. From the results, it can be concluded that the application of the Halbach array is an effective, economical, and prominent way to improve the performance of the VCRS compared to the pair of magnets.
Article
The vapour compression refrigeration system (VCRS) plays a vital role in the food preservation and it consumes more energy. The use of energy-efficient refrigerants, phase change materials (PCMs) in the condenser and evaporator, and the replacement of existing components, as well as nano-refrigerants, are all efforts made to increase the energy efficiency of the VCRS from different perspectives. Among them, the PCMs play a prominent role and gives sustainable energy efficiency in VCRS. This paper investigates and clarifies the energy efficiency of VCRS can be improved by incorporating a PCM into the evaporator cabin. The experimental results demonstrated substantial effects on system performance such as an improvement in COP of 7.1%, a decrease in per day energy consumption by 6.7%, and comparatively smaller temperature fluctuations within the freezer cabinet. The exergy efficiency is increased and Total Equivalent Warming Impact (TEWI) is decreasing than that of the system without PCM by 7.6 and 7% respectively. This technique is integrated into the VCRS, leading to savings in energy while also being useful for power interruptions common in areas with low grid reliability.
Article
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Solar photovoltaic to derive a small dc domestic refrigerator is becoming beneficial for remote areas where electricity is not available. This article presents an experimental energetic and exergetic analysis for a small dc refrigerator driven by a solar photovoltaic (PV) panel. The performance parameters, such as exergy losses compressor, exergy losses condenser, exergy losses expansion valve, exergy losses evaporator, efficiency exergy refrigerator, average optimum exergy efficiency (refrigerator), efficiency system (PV panel plus dc refrigerator) were investigated. The mentioned parameters were measured along the time of the day under the climate of Baghdad city. The experimental test has been carried out with load refrigerator (5 liters of water), to the evaluate the average optimum value of the refrigerator exergy efficiency under different thermostat. this work aims to identify an optimal average exergy loss for D.C refrigerator during the day, which can work at the optimum condition in evaporator temperature. The average exergy losses optimum value in evaporated temperature (-6) is 24.63
Article
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The typical domestic refrigerator employs a blind and periodic defrost strategy that leads to the clogging of the evaporator between the consecutive defrost cycles. The clogging of the evaporator causes a loss in performance which can be minimized using the demand defrost technique. The demand defrost systems proposed in the literature rely on the detection of frost as the defrost triggering criterion, rather than the real-time quantification of the thickness of frost. The initial frost layer improves the performance and therefore, the thickness of frost must be taken into consideration. Frost becomes detrimental only after it crosses a critical threshold. Defrosting the system at lower thicknesses may lead to frequent defrosting cycles which in turn increases the defrost energy. Therefore, the defrost triggering criterion must be selected tactfully to utilize the benefit of the initial frost layer along with the minimization of the defrost energy. In this article, a novel real-time thickness of the frost-based demand defrost technique is presented for a domestic refrigerator. A hybrid system comprised of a frost detection and defrosting modules is employed to quantify the thickness of frost in real-time and to defrost the evaporator using a 12 W heater. The effect of the thickness of the frost-based defrost threshold on the energy consumption of the refrigerator is evaluated. The defrost threshold of 6 mm yields the maximum energy conservation of 10% as compared to the default blind and periodic defrost strategy of the test refrigerator.
Article
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Hermetic compressors are essential components of domestic refrigerators and freezers and are usually designed to operate in ambient temperatures under 32°C. This study measures the discharge and shell temperatures of hermetic compressors at different ambient temperatures. To this end, calorimetric tests are conducted in three different hermetic compressors to define the impact of tropical ambient temperatures on the discharge and shell temperatures. Environmental temperatures of 35, and 38°C and voltages of 93, 115, and 127 V were considered during the tests. Thi results are compared to the nominal parameters at 32°C and 115V. Furthermore, to identify if the wear-out of the different components affect the discharge and shell temperatures, the three compressors were tested in the calorimeter after an accelerated life test. In all cases, the evaporation temperature was controlled at -23 °C. Results show that the discharge and shell temperatures of hermetic compressors increase with the ambient temperature. Additionally, it is evidenced that the technology of hermetic compressors strongly influences the discharge and shell temperatures.
Article
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Domestic refrigeration appliances are standard household commodities. Although policies, such as the energy labelling, prompted technical improvements and decreased appliance energy consumption throughout recent decades, important parameters were disregarded. These refer to the efficiency loss over time and the consumer behaviour. The objective of this contribution was to develop a dynamic energy model to determine the power consumption of refrigeration appliances considering degradation factors and behaviour. These were included by model parameters for direct consumer interactions, such as the storage behaviour, door openings and temperature setting, as well as indirect actions, e.g. exposing an appliance to specific temperature conditions at an installation site. For this, an online-survey was conducted to evaluate the consumer behaviour. A total of 706 consumers participated in the national questionnaire, serving as input for the dynamic energy model. It was found that the efficiency loss increases the power consumption by at least 1% annually, leading to an excess of 10% after 10 years of usage. Another important finding was that 32.5% of appliance's power consumption results from consumer behaviour, whereas the promotion of behavioural changes leads to a significant decrease of the consumer-induced consumption. Consequently, this study provides a tool to evaluate the impact of policies targeting refrigeration appliances, stressing that efficiency loss and behaviour should be integrated into future policy approaches.
Article
This study conducted to evaluate the effect that melting temperature and the amount of phase change materials (PCMs) has on energy consumption and temperature behavior of a household freezer. Two eutectic PCMs, serving as cold storage elements, were innovatively configured in a cascade‐like arrangement on six trays of a freezer with respect to the air temperature distribution of the interior compartment in order to reduce temperature fluctuations inside the freezer and to lower energy consumption. The experimental results showed that the maximum reduction in energy consumption (13.42%) occurred by placing three PCM packs of 1.5 kg with a melting temperature of −18°C on the three upper trays of the freezer and three PCM packs of 1.5 kg with a melting temperature of −20°C on three trays located on the lower side of the freezer. The optimal values were 1.97 kg of PCM with a melting temperature of −18°C and 1.57 kg of PCM with a melting temperature of −20°C to achieve the highest reduction rates of energy consumption and temperature fluctuations.
Article
Condensation may occur on the outer surfaces of the cooling devices in high humidity ambient. Especially the refrigerator door gasket insulation and flexibility is critical and that needs to be designed well. In this study, thermal temperature distribution and critical points of a refrigerator gasket are modeled by experimental investigations and the parameters of a new design are clarified by analysis. To influence the structure of the temperature distribution at certain points, various air chambers have been formed in the seal section. The effect of these air chambers' location and average temperatures on the outside of the gasket was observed and the temperature of the potential condensation zone was increased.
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Energy-efficiency labels are intended to better inform consumers at the point of sale about unobservable product characteristics. The EU Energy Label is globally one of the largest labeling schemes and obligates manufacturers of white goods to self-certify the energy efficiency index (EEI) of their product. The integrity of the scheme is reliant on manufacturers' compliance with the certification protocol and accurate declaration of the certification results. I construct a database that contains the testing data of 212 refrigeration devices sold on EU markets before and after the introduction of the label and compare self-reported and third-party verified EEIs. I find that under the label (1) there is evidence for bunching in self-certified EEIs, but not in verified EEIs, pointing to misreporting; (2) for the average model, self-certified EEIs understate equivalent energy consumption by 13 to %; (3) understatement clusters at class boundaries; and (4) well over half of the reporting discrepancy can be attributed to systematic factors rather than error. This can explain a significant share of the so-called 'Energy Efficiency Gap.' Before the introduction of the label, there is no evidence for bunching and substantially less underreporting of energy efficiency performance. In its current implementation, the EU Energy Label therefore plausibly induces misreporting, partly negating the intended information gains and impacting negatively on information-attentive consumers.
Article
User interactions with a refrigerating appliance, such as opening doors and insertion of food and drink to be cooled and stored, increase energy consumption. This investigation quantifies the energy impact of user interactions for 235 appliances in homes covering more than 65,000 appliance-days of use. User heat loads are highly variable from day-to-day within a household and are also quite variable across households. A linear mixed model statistical analysis using the number of householders, appliance size, indoor and outdoor ambient air temperatures has been conducted to develop a quantitative model of average sensible and latent heat load resulting from user interactions. A key aspect of user interaction is door openings. Instrumented data collection of door openings in homes for 66 appliances measured over an average of six months have been analysed by household size. A linear regression was conducted and analysis showed that door openings correlate well with user heat loads.
Article
Efficiency improvement of household refrigerators exerts extensive influences on the reduction in residential energy consumption and alleviation of environmental pollution. Controllable loop thermosyphons (CLTs) are low-cost, high-precision heat transfer control devices that can be potentially applied in refrigerators as crucial energy saving and temperature management components. A novel refrigerator with CLTs is proposed in this study. The evaporator in fresh food compartment is removed, the cold loss of the topside freezer is partly reused by the CLTs to cool the fresh food compartment in intermittent mode, and the overall cold loss of the refrigerator is efficiently reduced. The energy saving behaviour of the refrigerator is numerically studied based on tested temperature boundary conditions. The energy saving mechanism is comparatively analyzed, and the impacts of the operating condition, installation position of the CLTs, and ambient temperature are investigated. The energy saving ratio of the novel refrigerator increases from 12.9% to 19.5% when the ambient temperature rises from 17.0°C to 31.0°C, the operating condition varies from 1 to 4, and the locations of CLTs from the inner wall of the freezer are changed from 2.1 to 4.9 mm. Results preliminarily prove the energy saving capability of the novel refrigerator.
Thesis
Current power generation scenarios all over the world are not climate friendly as the generation systems are mainly dependent on fossil fuels that produce greenhouse gas (GHG) which contributes to global warming. This thesis presents an economical expediency of gridconnected hybrid (PV/Wind turbine) power system model by investigating the potentials of the wind and solar energy. It also conducts a feasibility analysis to explore the potentialities of green energy at different locations namely Kuakata, Sitakunda, Magnamaghat, Dinajpur, Rangpur and Khulna in Bangladesh. Initially, a flowchart of the proposed hybrid power system model is developed and then a hybrid model is designed with varying the contributions of renewable resources for the considered coastal region and the northern part of Bangladesh using a software tool named Hybrid Optimization of Multiple Energy Resources (HOMER). The simulation results are calculated for finding the cost of energy (COE), net present cost (NPC), total annualize cost, annual real interest rate, capital recovery factor (CRF), fraction of renewable energy (RE) contribution and greenhouse gas emission in terms of tons/year from which an optimum combination of RE sources and fraction of different RE sources in the designed hybrid power plant are determined. Sensitivity variables, such as range of wind speed, solar radiation, PV panel price, wind turbine hub height, are defined as inputs during simulation. The optimization process is carried out repeatedly for the sensitivity variables and the results are refined accordingly. Also, a comparison is made between off-grid and grid connected models on the basis of COE and GHG emission. The simulation results show that the proposed grid-PV-wind hybrid power system model is most suitable, economical and eco-friendly for the considered regions in Bangladesh.
Article
Domestic refrigerators have become an indispensable part of the modern life. Since they are connected to the electric mains and operate throughout the day and year, they consume a lot of energy. Several experimental studies show that the addition of phase change material in the refrigerators at various locations improves the energy efficiency of the refrigerators. In this work, an experimental study was conducted to explore and reveal the improvement in energy efficiency of a small-scale refrigeration system when PCM was applied between the evaporator coil and the insulation. It was observed that the addition of PCM for a thickness of 0.03 m could reduce the heat ingress inside the evaporator by 15–19%. Moreover, the compressor ON cycle time and the temperature fluctuation inside the freezer cabinet were also relatively lesser. The per day energy consumption was reduced by 15.7–17.3% and the improvement in COP was found to be 17.4% with the addition of PCM. The refrigeration system was able to retain its desired temperature level for a period of 5 h even after the power supply was switched OFF. This idea of incorporating PCM between coil and insulation could be extended to household refrigerators so as to reduce the energy consumption. This would come handy in case of power outages which are very common in places having low grid reliability.
Article
Domestic refrigerator is one of the major energy-consuming appliances, and the enhancement of its energy efficiency plays a vital role in implementing the energy conservation policies and green building concepts in residential sector. The major strategies used to improve the performance of domestic refrigerators are the replacement of existing components, use of alternative refrigerants and the reduction in condensing pressure. Therefore, in this work, the conventional air-cooled condenser has been replaced with water-cooled condensers such as shell-and-coil and brazed-plate heat exchangers to maintain a low compression ratio and condensing pressure. The performance of a domestic refrigeration system retrofitted with water-cooled condensers has been studied using experimental methods. The result showed that the system with water-cooled condensers reduces the pull-down time and the per day energy consumption by 70% and 3.5%, respectively. Moreover, the proposed system can improve the COP and exergy efficiency by 6.4% and 4.9%, respectively. Compared to shell-and-coil heat exchanger, the system with brazed-plate heat exchanger can reduce irreversibility and TEWI by 3.9% and 3.7%, respectively. In this study, the system with brazed-plate heat exchanger showed better performance than the shell-and-coil heat exchanger for all operating conditions.
Article
The defrosting method of the conventional household refrigerator increases freezer temperature during the defrosting operation, and defrosting efficiency reduces because the heater consumes more power than the amount of frost on the surface of the heat exchanger. To solve this problem, three defrost heater control methods, applicable to refrigerators equipped with conduction and radiation heaters, are being proposed. The control methods were classified as a method of simultaneously pulsating two heaters, method of individually pulsating two heaters, and method of step-by-step reduction of radiation heater power. The operation effect of each heater on freezer temperature was analyzed. For the three methods, a heater control optimization process was performed to reduce the temperature increase in the freezer. The power consumed by the heater was minimized and defrosting efficiency improved. The Best performance was observed when two heaters pulsated individually. For this method, the variation in freezer temperature, between before and after the defrost process, was reduced from approximately 11 °C to 5 °C. Additionally, the defrosting efficiency improved by 15%.
Article
A typical commercial refrigerator consists of multiple indoor units and a single outdoor unit. Recent application of inverter technology has greatly improved the performance and reliability of these systems by reducing power consumption and unnecessary on and off operation of the compressor. This requires information from indoor units including indoor units’ current and target temperatures. In many cases, however, inverter-type outdoor units may not have this kind of information due to incompatibility with indoor units. To take advantage of inverter technology even without indoor information, this paper focuses on two topics: detection of changes in indoor units’ refrigerating loads and selection of inverter frequency for constant speed operation. Results of this research will be a stepping stone for developing an algorithm for controlling inverter frequency without indoor information.
Article
Full-text available
Energy-performance improvements in consumer products are an essential element in any government's portfolio of energy-efficiency and climate change mitigation programs. Governments need to develop balanced programs, both voluntary and regulatory, that remove cost-ineffective, energy-wasting products from the marketplace and stimulate the development of cost-effective, energy-efficient technology. Energy-efficiency labels and standards for appliances, equipment, and lighting products deserve to be among the first policy tools considered by a country's energy policy makers. The U.S. Agency for International Development (USAID) and the United Nations Foundation (UNF) recognize the need to support policy makers in their efforts to implement energy-efficiency standards and labeling programs and have developed this guidebook, together with the Collaborative Labeling and Appliance Standards Program (CLASP), as a primary reference. This guidebook was prepared over the course of the past year with significant contribution from the authors and reviewers mentioned previously. Their diligent participation has made this the international guidance tool it was intended to be. The lead authors would also like to thank the following individuals for their support in the development, production, and distribution of the guidebook: Marcy Beck, Elisa Derby, Diana Dhunke, Ted Gartner, and Julie Osborn of Lawrence Berkeley National Laboratory as well as Anthony Ma of Bevilacqua-Knight, Inc. This guidebook is designed as a manual for government officials and others around the world responsible for developing, implementing, enforcing, monitoring, and maintaining labeling and standards-setting programs. It discusses the pros and cons of adopting energy-efficiency labels and standards and describes the data, facilities, and institutional and human resources needed for these programs. It provides guidance on the design, development, implementation, maintenance, and evaluation of the programs and on the design of the labels and standards themselves. In addition, it directs the reader to references and other resources likely to be useful in conducting the activities described and includes a chapter on energy policies and programs that complement appliance efficiency labels and standards. This guidebook attempts to reflect the essential framework of labeling and standards programs. It is the intent of the authors and sponsors to distribute copies of this book worldwide at no charge for the general public benefit. The guidebook is also available on the web at www.CLASPonline.org and can be downloaded to be used intact or piecemeal for whatever beneficial purposes readers may conceive.
Article
Full-text available
This study presents the effects of different operating variables on energy consumption of refrigerator-freezer that had two phases. The first phase is to investigate the effects of the number of door opening, duration of each door remain open, ambient temperature, cabinet load and thermostat setting position on energy consumption during the open door conditions. The second phase is to investigate the effects of the ambient temperature, cabinet load, thermostat setting position and open surface water pan area inside the cabinet on energy consumption during the closed door conditions. All the experiments were conducted in the environmental controlled chamber. The result shows that there is a great influence of different variables on energy consumption and average consumption is about 3.3 kWh day-1. The effects of number of door opening, ambient temperature and cabinet load are more compared to the others. The open door energy consumption is 40% more compared to the closed door test. It is found that the average of the maximum energy consumption is 27.3% more compared to average consumption and 55.6% more compared to average of the minimum consumption. If the users be serious, a significant amount of energy could be saved with the proper utilization of refrigerator-freezer.
Article
Two refrigerator-freezers, one with a top-mounted freezer and one with side-by-side doors, were tested in the laboratory to determine the sensitivity of their energy consumption to various operational factors. Room temperature, room humidity, door openings, and the setting of the anti-sweat heater switch were the factors examined. The results indicated that the room temperature and door openings had a significantly greater effect on energy consumption than the other two factors. More detailed tests were then performed under different room temperature and door-opening combinations. The relationship of door openings and the equivalent test room temperature was established. Finally, the effect on energy of different temperature settings was studied. Test results are presented and discussed.
Chapter
Performance standard tests have been selected by the ISO (International Standard Organisation) with the purpose of representing the real world average use. Within climatic classification the global standard testing was customised by the European Team CEN (Comitéuropé de Normalisation) TC 44 (with Italian Presidency and Secretariat at UNIMilan-1) to regional conditions. Energy label directive 94/2 EC (21.1.1994) and the Energy Efficiency Directive 96/57 EC (3.9.1996) have made the refrigeration standards legally binding for the performance and energy consumption declaration. Therefore the CEN TC44 has got a mandate from EU Commission to define the testing conditions. The four standards covering the cooling appliance type (H) have been condensed into the single EU standard (EN 153–1990 revised 1995). Cooling appliances of all climate classes should be labelled in Europe with energy consumption test at 25°C ambient temperature with closed door(s).
Article
This paper presents the effect of door openings of refrigerators/freezers on the energy consumption and compartment temperature variation by experimental approach. Two types of refrigerators/freezers were tested in the study. One is a type of variable frequency operation, while the other is a type of fixed frequency operation. The testing procedure was conducted under the ambient temperatures of 15 and 30 °C, and the door opening operation was carried out by one automatic robotic apparatus in an environmental control room. From the test results, energy consumption of refrigerators/freezers with door opening was found to increase by 10%, compared to the same product without door opening. Based on the compartment temperature variation status during door opening, control strategy was also proposed to improve the efficiency of variable frequency type of refrigerators/freezers. Future study on door opening control methodology can be addressed on usage's characteristics, so that it would help to control temperature variation and improve energy utilization by minimizing the effect of door opening.
Article
Household appliance penetration and ownership in Australia is higher than in western Europe, and close to North American levels. Most products are manufactured locally, by firms with international links and with access to both European and North American designs and technology. A significant share of the market is imported, mainly from New Zealand, Asia and Europe. Because of the relative mildness of the climate, appliances that carry an energy label (such as dishwashers, clothes washers, clothes dryers, and refrigerators and freezers) account for a greater share of household energy use than in most other developed countries. The energy efficiency of appliances in Australia increased steadily during the early 1980s, but the introduction of mandatory energy labelling in 1986 in some states saw a significant increase in the rate of change. The mandatory government energy labelling program, which is in force in most states, now includes refrigerators, freezers, room air conditioners, dishwashers, clothes washers and clothes dryers. A voluntary industry-based gas appliance energy labelling program is also in place for gas water heaters and flued space heaters. The Australian energy labelling program is widely regarded as among the most informative and salient in the world, and it may be extended to New Zealand over the next few years (many products in NZ already carry the label as the Australian and NZ markets are closely integrated). Label recognition and use is very high among recent and prospective appliance purchasers. The use of a static efficiency scale on the label, while assisting recognition and comprehension, has also reduced the competitive pressure on suppliers, as efficiency improvements have pushed many models to the top of the rating scale. In 1995, Australian energy ministers agreed to implement minimum energy performance standards (MEPS) for refrigerators, freezers, and electric storage water heaters, to take effect in 1999. The levels are relatively moderate, and the effect will be to complement the energy labelling program rather than to transform the energy efficiency of the market.
Article
In Japan, energy efficiency standards for domestic refrigerators were established in 1999 in accordance with the guidelines delineated by the Top-Runner program. The goal was an improvement in energy efficiency of approximately 30% compared with the year 1998 by the year 2004. This goal has been not only met but exceeded: the average annual electricity consumption of products shipped in 2004 was 290 kWh/year, a 55% reduction of the 1998 figure. Electricity consumption of refrigerators is measured using the Japan Industrial Standards (JIS) test procedures. However, existing surveys show significant difference in electricity consumption between the actual and the labeled. This paper analyzes the difference between actual values and labeled values of electricity consumption. Actual values were obtained by conducting two experiments. The first experiment measured electricity consumption of two high efficient refrigerators in a laboratory simulating actual use conditions. The refrigerators were found to consume two to three times more electricity than under JIS test conditions. The second experiment monitored over 100 refrigerators in households. According to the first year's result, the average annual electricity consumption was 65% larger than the JIS test value. Energy efficiency of refrigerator has been improved, but the significant difference in electricity consumption between the actual and the labeled might damage the public trust in labeling. The government began studying new standard and test procedure of refrigerators in September 2005. The JIS test procedures were revised to be much similar to real usage in January 2006 and the standards will be established by the end of the year.
Article
Over recent decades, energy savings and resource conservation have become increasingly important issues for debate, and this includes the residential sector. Since the introduction of the European Energy Label, the energy consumption of appliances has decreased drastically. Additionally, a number of guidelines have been published to assist the consumer in adopting more energy-saving behaviours. Refrigerators and freezers in particular are covered by these recommendations because they are large energy consumers in domestic households. In order to understand the influence of consumers' real life circumstances and their behaviour in relation to the energy consumption of refrigerators, a web-based survey was carried out. A total of 1011 participants in four European countries completed a questionnaire to allow the researchers to gain information about refrigerator characteristics and consumer behaviour in relation to refrigerator use. As well as demographic and socio-economic characteristics of the participants, data were collected on refrigerator configuration and specification, ambient conditions (ambient temperature, position near any heat sources), and consumer behaviours such as shopping frequency, loading of the refrigerator, door opening and food consumption. The study has shown that recommendations on energy efficient usage are not always observed. A major finding of the present study is that for 25% of refrigerators, correct operation is not ensured as these appliances are operated outside the temperature ranges specified according to their climatic classes. This suggests a lack of consumer information on this topic. Consequently, guidelines and recommendations will have to be revised and their dissemination to be improved in order to ensure the sustainable and safe use of domestic refrigerators.
Article
Sustainability is one of the most important issues facing the world today, and yet many consumers are confused about what the term means. The question of how to create and maintain a sustainable lifestyle is a complicated one. How can we live in a way that meets the needs of the present generation without compromising the ability of future generations to meet their own needs? Would consumers understand the issue better if we used the phrase ‘responsible consumption’? The Welsh Consumer Council is working on a number of projects that look at different aspects of sustainable development. Wales has one of the only governments in the world with a statutory duty to promote sustainable development, and yet patterns of consumption are spiralling out of control. If everyone in the world lived like consumers in Wales, we would need nearly two extra planets to sustain ourselves. In the fields of energy, food, waste, water, and travel, we are using up far more resources than can be replenished. This paper will examine the progress of sustainable development in Wales in the wake of the World Summit on Sustainable Development in Johannesburg in August 2002. It will provide an overview of current consumption patterns and will identify some of the main factors inhibiting people in Wales from making more sustainable consumer choices. It will examine the popular image of sustainability, and will also identify what drivers are in place to encourage sustainable consumption.
Article
Residential refrigerators are the largest domestic use of electricity in the US and most developed countries and, as such, have become a target for efficiency improvements. Laboratory tests of energy use are typically used to measure a refrigerator's energy consumption. Three different test procedures are widely used: the US Department of Energy, the International Standards Organization test, and the Japanese Industrial Standard. The features of the tests are compared and conversion factors reviewed. The DOE test is likely to yield the highest consumption of the three procedures. A critical factor is the relationship between a refrigerator's laboratory-based energy use and its consumption in a kitchen. The DOE test is the most carefully validated with field data. The DOE test, on average, over-predicts actual consumption in US homes by about 10%, but there is wide variation in field use for identical units. The factors affecting variation in energy use are reviewed. The ambient temperature in the kitchen is by far the most significant factor, while door openings and humidity are relatively minor. Field measurements suggest that maintenance measures, such as coil cleaning and gasket replacement, save little energy. Replacement of old refrigerators with new, efficient models often cuts refrigerator energy use by 60%. Significant reductions in refrigerator electricity use can be expected during the next decade in the US and Europe.
Article
ISO 8187, ISO 8561, and ISO 7371 are the relevant test standards for household refrigerating appliances. This paper presents the possibility of introducing ISO household refrigerator–freezer test standards in Malaysia. An experiment was conducted to investigate the effect of room temperature, door opening, thermostat setting position, relative humidity, and loading on energy consumption of a household refrigerator–freezer. With the experimental data, a multiple regression equation is developed to investigate their combined effect. Finally, energy consumption according to the regression equation with optimum setting conditions is compared with ISO standard test conditions. Our comparison reveals that ISO refrigerator–freezer test standards are applicable with respect to Malaysian climatic conditions and usage patterns.
Article
Refrigerator-freezers energy consumption is greatly affected by room temperature, door opening and thermostat setting position. Two frost free household refrigerator freezers of the same capacity were tested in the laboratory to determine the sensitivity of their energy consumption to various usage conditions. The experiments were conducted to investigate the effect of single variables, such as temperature, thermostat setting positions and door opening, and their combined effect on energy consumption. Our investigation reveals that room temperature has the higher effect on energy consumption, followed by door opening. Thermostat setting position has the lower effect on energy consumption. More detailed tests were performed under different room temperature, thermostat setting position and door opening conditions. With the experimental results, a first order mathematical model has been developed to investigate their combined effect on energy consumption. The test results are discussed and presented.
Conference Paper
An experiment was conducted to investigate the effect of temperature, door opening, thermostat setting position, relative humidity, and loading on energy consumption of a household refrigerator-freezer. The authors' investigation reveals that temperature has the greatest effect on energy consumption followed by loading. Next greatest effect are due to door opening and thermostat setting position. Relative humidity has minimal effect on energy consumption. With the experimental data, a multiple regression equation has been developed to investigate their combine effect
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