Article

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

Authors:
To read the full-text of this research, you can request a copy directly from the authors.

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.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... 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
Full-text available
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.
... The study's significance is further strengthened by Fatemeh Ghadiri's research (F Ghadiri, 2014), which examined the impact of selecting suitable refrigeration cycle components on energy consumption optimization in household refrigerators. Erik Bjork (E Bjork, 2006) explored the performance of domestic refrigerators under varying conditions, such as expansion device, refrigerant charge, and ambient temperature, aligning with the findings of Jasmin Geppert's study (J Geppert, 2013), which analyzed influential factors affecting domestic refrigerators' energy consumption during everyday use. ...
... This system consists of a compressor, condenser, expansion device, internal heat exchanger, and evaporator. The corresponding components are illustrated in the figure 2. In the transient phase, the compressor, the condenser and the evaporator were modeled, while the transient stages of the expansion valve was considered negligible compared to the heat exchangers' transient stage (J Geppert, 2013). The heat transfer between the compressor and the environment was taken into account in the calculations. ...
Conference Paper
Full-text available
The energy consumption in refrigerators can be relatively easily calculated by considering the system's stationary behavior through the balance of mass and energy. However, this analysis proves to be simplistic when attempting to predict consumption closer to reality, as it fails to account for any system failures or sudden changes, causing it to transition from a steady state to transient state. This can occur simply by opening the refrigerator door. Moreover, in real situations, refrigerators do not constantly operate in a steady state as it would lead to excessive consumption and energy demand. Instead, they operate in time cycles, seeking to maintain temperatures close to those desired by the user. Thus, in order to develop an analysis that is useful in practical terms, and optimize energy consumption in real applications, it is necessary to model the cooling system in a way that does not keep it active for long periods of time, as this does not match reality and does not provide acceptable results for energy consumption. Energy consumption tests are time consuming, and a manner to decrease the time and cost in the product development phase is to predict properly an energy consumption test using well-knowm parameters that could be extracted fro a pull-down test. To study energy thermal conductance of heat exchangers, cabinet and compressor. This work aims to carry out this modeling using the Python programming language primarily, which will enable simulations and production of consumption graphs, using the experimental data. The obtained graphs will allow for the analysis of the temperatures of all components of the refrigeration system as well as the cabinet, as function of the time cycles.
... 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.
... Other factors, including cultural values and social norms [34,37], family size and people's lifestyles [38], educational attainment [39][40][41], and information penetration also influence household attitudes and cooking technology use [42,43]. Finally, geographical factors, ranging from regional economic development to the rural-urban divide, rate of urbanization, vegetation type, and climatic experiences like temperature and rainfall, can influence household energy choices [44][45][46][47][48]. ...
Article
Full-text available
Background The present study draws motivation from the United Nations Sustainable Development Goals and explores the nexus between access to modern cooking energy sources, responsible energy consumption, climate change mitigation, and economic growth. Using 2018 demographic and health survey data, the study examines the influence of key socioeconomic and demographic factors on household choice of cooking energy in Nigeria. Results The empirical results show that traditional energy sources are dominant among Nigerian households (74.24%) compared to modern energy sources (25.76%). Regarding energy demographics, male-headed households show more usage of modern energy sources (19.86%) compared to female-headed households (5.90%). Regional analysis reveals that the northwest region predominantly uses traditional energy sources (18.60% of the share of total traditional energy sources), while the southwest region shows the greatest usage of modern energy sources (10.52% of the share of total modern energy sources). Binary logistic regression analysis reveals the positive and statistically significant influence of wealth index, education, and geopolitical region on the likelihood of utilizing modern energy sources. Conversely, household size and place of residence indicate an inverse relationship with the likelihood of adopting modern energy sources. Conclusions These findings have important policy implications for energy efficiency, environmental sustainability, and improving the quality of life in Nigeria, which is currently plagued with significant energy poverty, especially in rural communities.
... In this context, Faghihi et al. [4] analyzed the flexible design of some of the components of the vapor compression cycle, for which they achieved improvements in the coefficient of performance (COP) from 10% to 25%, thus reducing the refrigerator's energy consumption. Gardenghi et al. [5] extensively evaluated the effect of ambient temperature on various parameters related to the refrigerator's performance, highlighting among their results an increase in energy consumption of up to 190% when the refrigerator goes from an ambient temperature of 25 • C to 43 • C. A similar increase was found by Geppert and Stamminger [6], where their results indicated an increase of up to 200% in energy consumption due to the effect of extreme ambient temperature conditions. These included the internal temperature of the compartment and the amount of food, representing the actual conditions of use of the refrigerator. ...
Article
Full-text available
Maintaining adequate temperatures for preserving food in a domestic refrigerator is a task that is affected by several factors, including the daily use of the appliance. In this sense, this work presents the development of a novel control system based on fuzzy logic that considers usage habits such as the amount of food entering the refrigerator and the frequency of opening doors. Thus, the control comprises input variables corresponding to the internal temperatures of both compartments, the thermal load entered, and the refrigerator door-opening signal. By simulating the usage habits of a refrigerator with a variable-speed compressor, the control performance was evaluated. The results showed that implementing fuzzy control using usage habits was robust enough to maintain adequate thermal conditions within the compartments and a lower thermal fluctuation concerning the reference control of the refrigerator (factory control). In terms of energy, the fuzzy control resulted in an energy saving of 3.20% with the refrigerator empty (without thermal load) compared to the reference control. On the other hand, the individual integration of the thermal load in the fuzzy control resulted in 2.08% energy savings and 5.45% for the integration of the thermal load compared to the reference control. Finally, considering the combination of usage habits, the fuzzy control presented a higher energy consumption than the reference control, around 9.7%. In this case, the fuzzy control maintained more favorable thermal conditions in both compartments, whereas the reference control presented a warmer thermal condition in the freezer.
... Chiou et al. introduced a fuzzy temperature control method for multi-unit room air conditioners to improve energy efficiency [11]; however, the energy efficiency of refrigeration systems was not addressed. Jasmin et al. (2013) investigated domestic refrigerators' energy consumption [12]; the operating condition variables (ambient temperature, thermostat setting position, and heat load) that affect the energy consumption of refrigerators were evaluated; their results revealed differences in the absence of information on the indoor unit. Ali et al. (2020) studied the single-phase induction motor drive of a refrigerator compressor [13]; they developed an algorithm to improve the energy efficiency of cooling systems through modeling and analysis of commercial refrigeration systems. ...
Article
Full-text available
Despite the serious threat of global warming caused by carbon emissions, commercial refrigeration systems that generate cooling are unable to adjust their usage time. Therefore, it is essential to enhance the energy efficiency of refrigeration systems themselves. Recently developed refrigeration systems offer improved energy consumption efficiency as they utilize inverter-type outdoor units that can communicate with indoor units. However, traditional legacy refrigeration systems still suffer from poor energy efficiency because the existing indoor units cannot communicate with inverter-type outdoor units. Hence, this paper introduces a heuristic energy efficiency improvement algorithm for commercial refrigeration systems using legacy indoor units when an inverter-type outdoor unit is installed. In particular, to reduce the computational complexity of the process of selecting the optimal temperature difference and target low-pressure variables that can enhance energy efficiency, the algorithm employs the Monte Carlo method. Finally, the performance of the proposed heuristic energy efficiency improvement algorithm was evaluated in a laboratory environment to confirm its applicability.
... Geppert, et al [18] evaluaron a través de estudios empíricos, el consumo de energía de los refrigeradores con varios factores operativos, como reflejo de las condiciones de la vida real. Se probaron cuatro refrigeradores diferentes en condiciones controladas de laboratorio, con tres variables [posición de ajuste del termostato, temperatura ambiente y calor adicional almacenando comida caliente] y en tres niveles diferentes. ...
Article
Full-text available
Knowing the temperature of the discharge and casing of hermetic domestic refrigeration compressors that operate in tropical climate conditions, allows us to guarantee the correct operation and useful life of these equipment. This article presents the results of tests in secondary fluid calorimeter of the behavior of the temperature of the discharge and casing to hermetic compressors of three manufacturers. The tests were carried out before and after the life test, at different ambient temperatures, voltages, with and without subcooling. The results have shown that there are significant differences between the discharge and casing temperature values of hermetic compressors, for the ambient temperature range studied. The necessary search for greater efficiency in refrigeration systems leads to the fact that the information obtained could be used in the study of improvements for the design of compressors that perform in tropical climates.
... Products energy consumption is strongly influenced by their operating conditions and on users' behaviours (Geppert and Stamminger, 2013;Hueppe et al., 2021). For instance, the consumption of HVAC systems is highly dependent on the outdoor temperature, dishwashers could consume 6-73% more energy when used with different programmes and refrigerators consumed up to 47% more energy, considering different door opening patterns (CLASP et al., 2017). ...
Article
Full-text available
The improvement of energy efficiency of products is a key pillar of climate and energy strategy in the European Union (EU). The first EU product policies were adopted in the late 1970s, and they have evolved to become a coherent set of implementing measures under framework directives that harmonise and refine the regulatory process. After years of weak implementation, considerable progress in terms of scale and ambition has been achieved in the last decade. In 2020, product mandatory measures covered 50% of the EU total final energy consumption, leading to 46 Mtoe energy savings. This paper describes the available policy instruments to promote energy efficiency and remove the market barriers hindering the penetration of the best performing technologies. It offers a review of the progress made over these last 40 years of EU product policies, describing the Energy Labelling, the Minimum Energy Performance Standards (MEPS), the Ecodesign Directive and the voluntary agreements (EU Ecolabel and Green Public Procurement). Moreover, it highlights the remaining challenges and provides policy recommendations to further exploit the EU potential to save energy from products.
... This value was adapted to obtain the consumption at 7°C. According to Geppert and Stamminger (2013), electricity consumption is about 3.5 % lower per degree decrease in the refrigerator's internal compartment, thus an annual consumption of 1465kWh/m 3 *year at 7°C was obtained. Furthermore, the density of the broccoli (300 kg/ m 3 ) has been obtained from Eslava Sarmiento (2019). ...
Article
Full-text available
The consumption stage has been identified as the largest producer of food waste (FW) across the food supply chain (FSC), with fruit and vegetables being the most affected product category. The present study aims to determine the optimal storage scenario at household level to avoid food waste and which has the lowest environmental footprint. Broccoli was stored under different storage conditions: unbagged or bagged (periodically opened) in bioplastic bags inside a domestic refrigerator at 5 or 7 °C for 34 days and then analysed for relative humidity (RH), sensory properties and bioactive compounds. A life cycle assessment (LCA) was conducted to evaluate the environmental profile of 1 kg of broccoli purchased by the consumer (cradle-to-grave). At day 0 (base scenario) the carbon footprint was 0.81 kg CO2 eq/kg, with the vegetable farming being the main contributor to this environmental impact, mostly driven by fertiliser (production and its emissions to air and water) and irrigation (due to electricity consumption for water pumping). Quality and food waste depended on time and storage conditions: For short storage times, within three days, the best quality combined with the lowest environmental footprint was for unbagged broccoli at 7 °C and no household food waste. However, this scenario had the highest food waste level from day 3 onwards, with increased resource loss and overall environmental footprint. For long-term storage, using a bag and storing at 5 °C helped to reduce food waste with the lowest environmental footprint. For example, at 16 days, this scenario (bagged at 5 °C) could save 4.63 kg/FU of broccoli and 3.16 kg CO2 eq/FU compared to the worst scenario (unbagged at 7 °C). Consumers are the key to reducing household food waste and this research provides the knowledge for improvement.
... Therefore, it is increasingly important to find a feasible energy saving solution [1]. In the household appliances, the refrigerator as a 24-hour continuous operation of household appliances, has become the highest energy consumption of electrical appliances [2]. According to statistics, China produces more than 80 million refrigerators each year, with a population of about 300 million, and its energy consumption accounts for about 40 -50 % of residential electricity consumption [3]. ...
Article
In this study, a kind of phase change materials (PCMs) with a low melting point (around 0 ℃) was prepared using n-decyl alcohol (DA) and lauryl alcohol (LA) as PCM, expanded graphite (EG) as supporting matrix. Nano silicon carbide (SiC) as a thermal conductivity promoter was added to modify the composite PCM. Expanded graphite with strong adsorption performance was used to not only prevent the leakage, but enhance the thermal conductivity. Leakage experiments showed that the maximum adsorption rate of DA-LA in composite PCM was 92 wt.%. The physical properties and chemical compatibility of composite PCM were studied, and the results showed that the raw materials were well absorbed and dispersed homogeneously into the porous structure of the EG, and they were only a physical bond with each other without chemical reaction. The melting and solidification temperature of composite PCM with the SiC mass ratio 3 wt.% was -0.85 ℃ and 1.08 ℃, and the latent heat of melting and solidification was 85.62 J/g and 74.94 J/g, respectively. the thermal conductivity of composite PCM with 9 wt.% SiC addition was 1.61, which was more than 4.19 times that of pure DA-LA. Thermogravimetric Analysis (TGA) experiment showed that composite PCM had outstanding thermal stability and durability. The present study confirms that this composite PCM is a potential candidate for cold energy storage in refrigerator applications.
... 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
Full-text available
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
Full-text available
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
Full-text available
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
Full-text available
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
Full-text available
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
Full-text available
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.
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
Full-text available
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
Full-text available
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
Full-text available
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
Full-text available
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.
Article
Full-text available
In the perspective of reducing the household energy consumption, current research in conventional refrigeration is concentrating on introducing innovative designs and enhances the energy efficiency of the refrigeration system. This research work compares the performance of the domestic refrigerator by employing hot wall air cooled and box type shell and tube water cooled condenser. The energy and exergy analysis methods help to localize exergy losses in the refrigerator. The investigation is carried out according to ISO 15502:2005. Experimental studies were conducted in the same refrigerator unit operating with a different condenser to determine the coefficient of performance, exergy efficiency, and exergy loss in all components of the domestic refrigerator. The experimental result shows that COP is increased by 18 20% and the exergy efficiency of the refrigerator with water cooled condenser unit is found to be higher by 6.89 9.13% than the one with a hot wall air cooled condenser. The per day energy consumption of a refrigerator with a water cooled condenser reduces by 17% in comparison with conventional refrigerator. The irreversibility of the refrigerator with the water cooled condenser is reduced by 34 % than that of the conventional system under similar operating conditions. The total equivalent warming impact of refrigerator working with the water cooled condenser is 16% lower than that the refrigerator with air cooled condenser. The utilization of water cooled condenser in household refrigerators enhances energy efficiency.
Article
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
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
Energy consumption of domestic refrigerators using electronic energy saving devises
  • J Van Den Keybus
  • R Belmans
J. Van den Keybus, R. Belmans. Energy consumption of domestic refrigerators using electronic energy saving devises. <http://www.esat.kuleuven.be/electa/ publications/fulltexts/pub_1147.pdf> [accessed 09.02.12].
Findings of the Cold II SAVE study to revise cold appliance energy labelling and standards in the EU
  • P Waide
P. Waide. Findings of the Cold II SAVE study to revise cold appliance energy labelling and standards in the EU. In: ECEEE 2001 summer study: further than ever from kyoto? Rethinking energy efficiency can get us there, Mandelieu, France; 2001.
BNC 11 Domestic refrigerator test standard vs real-use energy consumption
  • Mtp
MTP. BNC 11 Domestic refrigerator test standard vs real-use energy consumption. <http://www2.env.uea.ac.uk/gmmc/energy/energy_links/eu-labels/standard_vs_real_refrigerator.pdf> [accessed 10.12.10].
Umweltschonende Nutzung des Kühlgerätes im privaten Haushalt. Dissertation: University of Bonn
  • K Lepthien
Lepthien K. Umweltschonende Nutzung des Kühlgerätes im privaten Haushalt. Dissertation: University of Bonn; 2000.
Methodology study eco-design of energy using products (MEEUP) for European Commission, Final Report. refrigerators and freezers
  • Van Holsteijn
  • Kemna
Van Holsteijn en Kemna BV (VHK), Methodology study eco-design of energy using products (MEEUP) for European Commission, Final Report. refrigerators and freezers, product case 5. Delft: Van Holsteijn en Kemna BV; 2005.
The effect of ambient temperature, ambient humidity and door openings on household refrigerator energy consumption. MSME thesis
  • Ms Alissi
MS. Alissi. The effect of ambient temperature, ambient humidity and door openings on household refrigerator energy consumption. MSME thesis. Purdue University, West Lafayette; 1987.
Household refrigerators and freezers. In: ASHRAE handbook: refrigeration, Amer Society of Heating Refrigerating, and Air-Conditioning Engineers
  • Ashrae
ASHRAE. Household refrigerators and freezers. In: ASHRAE handbook: refrigeration, Amer Society of Heating Refrigerating, and Air-Conditioning Engineers; 2002 [chapter 49].
Energiesparen im Haushalt: So schonen Sie Umwelt und Geldbeutel
  • L Wicke
  • T Boehmer
L. Wicke, T. Boehmer. Energiesparen im Haushalt: So schonen Sie Umwelt und Geldbeutel, Deutscher. Taschenbuch-Verlag, Muenchen; 1998.
Directive 96/ 57/EC of the European Parliament on energy efficiency requirements for household electric refrigerators, freezers and combinations thereof
The European Parliament and the Council of the European Union, Directive 96/ 57/EC of the European Parliament and of the Council of 3 September 1996 on energy efficiency requirements for household electric refrigerators, freezers and combinations thereof. Official Journal of the European, Communities; 1996 [Online].
on the indication by labelling and standard product information of the consumption of energy and other resources by household appliances
The Council of the European Communities. Council directive 92/75/EEC of 22 September 1992 on the indication by labelling and standard product information of the consumption of energy and other resources by household appliances. Official Journal of the European, Communities; 1992 [Online].
Methodology study eco-design of energy using products (MEEUP) for European Commission, Final Report. refrigerators and freezers, product case 5
  • Bv Van Holsteijn En Kemna
Van Holsteijn en Kemna BV (VHK), Methodology study eco-design of energy using products (MEEUP) for European Commission, Final Report. refrigerators and freezers, product case 5. Delft: Van Holsteijn en Kemna BV; 2005.
Do refrigerator thermostat setups save energy?
  • A K Meier
Meier AK. Do refrigerator thermostat setups save energy? Home Energy 1994;11:11.
Commission delegated regulation (EU) No 1060EU of the European Parliament and of the Council with regard to energy labelling of household refrigerating appliances
The European Commission. Commission delegated regulation (EU) No 1060/ 2010 of 28 September 2010 supplementing Directive 2010/30/EU of the European Parliament and of the Council with regard to energy labelling of household refrigerating appliances. Official Journal of the European Union; 2010 [Online].
The European Parliament and the Council of the European Union, Directive 96/ 57/EC of the European Parliament and of the Council of 3 September 1996 on energy efficiency requirements for household electric refrigerators, freezers and combinations thereof
The European Parliament and the Council of the European Union, Directive 96/ 57/EC of the European Parliament and of the Council of 3 September 1996 on energy efficiency requirements for household electric refrigerators, freezers and combinations thereof. Official Journal of the European, Communities; 1996 [Online].
amending directive 94/2/EC implementing council directive 92/75/EEC with regard to energy labelling of household electric refrigerators, freezers and their combinations
The Commission of the European Communities. Commission directive 2003/ 66/EC of 3 July 2003 amending directive 94/2/EC implementing council directive 92/75/EEC with regard to energy labelling of household electric refrigerators, freezers and their combinations. Official Journal of the European Union; 2003 [Online].
Methodology study eco-design of energy using products (MEEUP) for European Commission, Final Report. refrigerators and freezers, product case 5. Delft: Van Holsteijn en Kemna BV
  • B V Van Holsteijn En Kemna
Van Holsteijn en Kemna BV (VHK), Methodology study eco-design of energy using products (MEEUP) for European Commission, Final Report. refrigerators and freezers, product case 5. Delft: Van Holsteijn en Kemna BV; 2005.
The effect of ambient temperature, ambient humidity and door openings on household refrigerator energy consumption
  • Ms
  • Alissi
MS. Alissi. The effect of ambient temperature, ambient humidity and door openings on household refrigerator energy consumption. MSME thesis. Purdue University, West Lafayette; 1987.
SPSS Version 16 Einfuehrung in die moderne Datenanalyse. Muenchen: Pearson Studium Verlag
  • A Buehl
Buehl A. SPSS Version 16 Einfuehrung in die moderne Datenanalyse. Muenchen: Pearson Studium Verlag; 2008.
Actual energy consumption of top-runner refrigerators in Japan
  • T Tsurusaki
  • Y Iwafune
  • Y Shibata
  • C Murakoshi
  • H Nakagami
T. Tsurusaki, Y. Iwafune, Y. Shibata, C. Murakoshi, H. Nakagami. Actual energy consumption of top-runner refrigerators in Japan. In: EEDAL 2006 international conference on energy efficiency in domestic appliances and lighting. London, UK; 2006.