Domestic Refrigerator Research Articles

A domestic refrigerator's potential of using hydrocarbon blends as refrigerants

A domestic refrigerator's potential of using hydrocarbon blends as refrigerants

Optimal Control of a Domestic Frost-Free Refrigerator Inlet Freezer from the Perspective of Reducing Energy Consumption

This study is dedicated to the development of a mathematical model based on shape optimal control of the inlet domestic frost-free refrigerator in the context of energy consumption reduction. A three-dimensional thermofluid model is established for the numerical studies. As the physical system (with shelves and fruits) can be seen as a porous medium, the coupled state equations of the transport mechanism (for velocity and temperature fields) are governed by Navier–Stokes–Forchheimer/Fourier equations. Then, based on the finite element method, the numerical scheme computation is made with FreeFem++ software (Version 4.6). Numerical results are shown for three different cases: empty without shelves, empty with shelves, and loaded with foods. For each case, the velocity and temperature fields’ results are discussed for the optimal configurations. The characterization of these physical parameters would help engineers in domestic frost-free refrigerator design.

Experimental correlations to predict the cooling performance and compressor energy consumption of domestic refrigerator with phase change material

ABSTRACT The phase change material technology is continuously evolving in commercial market. In order to develop/design PCM modules of different capacity and different PCM material, it is necessary to develop the equation which will provide required information for development of PCM module. This paper establishes correlations to predict backup time and equivalent energy consumption of domestic refrigerator based on experimental data of testing of PCMs, potassium chloride (KCl), sodium chloride (NaCl), and sodium fluoride (NaF) dissolved in water for PCM masses varying between 0 and 1.75 kg in both closed door and door opening conditions. This paper investigates the impact of incorporating a phase-change material (PCM) on the cooling performance and energy consumption of a domestic refrigerator. The PCM module, filled with potassium chloride (KCl), sodium chloride (NaCl), and sodium fluoride (NaF) dissolved in water, is strategically placed on the contact surface of the refrigerator’s evaporator coil. The utilization of PCM aims to mitigate cabin temperature fluctuations and reduce overall energy consumption. Through experimental evaluation, the study assesses the effectiveness of different phase-change materials in enhancing the cooling performance and energy efficiency of the domestic refrigerator. The findings reveal that the incorporation of phase-change material significantly improves the cooling performance, as evidenced by the extended backup time during power cut-off and a reduction in compressor energy consumption. The tested phase-change materials, including KCl, NaCl, and NaF, demonstrate varying impacts on performance parameters. The backup time for closed-door tests is 1.83 – 1.03 times longer than that for door opening tests, respectively. The backup time of door opening tests is shortened due to heat entered to the cabin for all masses, between 45.45% and 3.23%. The backup time is increased by the masses of PCM KCl between 14% and 155%, the masses of PCM NaCl between 18% and 159%, and the masses of PCM NaF between 27% and 182%. The equivalent energy consumption for door opening tests is 1.12–1.02 times larger than that for the closed-door tests. The correlation equation established based on the existing experimental data can be used to accurately predict the backup time and equivalent energy consumption of refrigerator for tested PCM of any mass within the interval of 0 Kg to 1.75 Kg with ± 10% accuracy.

Development of the National Cooling Action Plan of the Philippines

Abstract The Philippines NCAP was developed to account for the environmental impacts of energy consumption (indirect impacts) and use of high-GWP refrigerants (direct impacts) from the RAC Sector that can be mitigated by transitioning to more climate-friendly and higher-efficiency refrigerants. Utilizing the NCAP Methodology developed by the UNEP-led Cool Coalition, UN ESCAP in collaboration with Alliance for an Energy Efficient Economy (AEEE) together with and built on the expertise of the Cool Coalition’s NCAP Working Group facilitated by The Kigali Cooling Efficiency Programme (K-CEP), the Philippines NCAP was launched by the Philippines Department of Energy – Energy Utilization and Management Bureau, Department of Environment and Natural Resources, and United Nations Development Programme (Philippines Country Office). This paper presented the Reference Cooling Scenario (RCS) and the Sustainable Cooling Scenario (SCS) adopted from the business-as-usual (BAU) and Clean Energy Scenario (CES) of the Philippine Energy Outlook. With these assumptions on RCS and SCS, the domestic refrigeration sector will save 4.41 TWh while the residential cooling sector will save 12.15 TWh. There is a net effect in total emission reduction estimates of 10.68 MT CO2 equivalent which is close to 12 % of the unconditional target submitted to UNFCCC.

Exergetic analysis of a domestic refrigerator with an innovative mini-channel flat tube condenser

Exergetic analysis of a domestic refrigerator with an innovative mini-channel flat tube condenser

Optimizing photovoltaic system configurations for domestic refrigerators in Miliana, Algeria: a simulation study

This study investigates the optimal configuration of a photovoltaic system to operate a home refrigerator with a power consumption of 130 watts. The research focuses on the city of Miliana, Algeria, analyzing the effects of local solar radiation and ambient temperature on battery charging dynamics throughout the year. Using MATLAB simulation techniques, we identified a 450 W solar panel coupled with a 150 Ah battery as the most efficient configuration to meet the power requirements of the refrigerator. Our findings highlight the fast charging capability of this PV system, achieving fast battery charging while maintaining a balance between energy production and consumption. However, we have also determined that increasing battery capacity beyond this limit results in longer charging times, shorter battery life cycles, and higher costs, which are counterproductive to the PV refrigerator-coupled system. The study emphasizes the importance of incorporating local climate conditions into the design of solar energy systems to ensure robust and sustainable energy solutions. The proposed configuration promises to reduce dependence on traditional energy sources, encourage the use of renewable energy in residential environments, and enhance environmental sustainability. Future research should evaluate these configurations in diverse geographic locations to validate and optimize the system for broader application, and explore advanced battery technologies to further improve efficiency and longevity.

Assessing refrigerated preservation performance using Listeria predictive microbiology models and temperature data: Refrigerator performance indicator and time-temperature equivalent.

Time-temperature data for queso fresco (QF) cheese varieties stored in a residential refrigerator operating at 5°C and a predictive microbiology secondary model for Listeria monocytogenes in QF were used to estimate a refrigerator performance indicator (RPI) of microbial preservation. RPI values were used to assess how compressor technology (single [SS] and variable speed [VS]), ambient temperature (21.1°C [LT] and 32.2°C [HT]), and refrigerator load (22.5kg regular load and 39kg higher load) affected preservation performance. All deterministic and probabilistic RPI estimations slightly exceeded the desirable 1.0 value, i.e., the variable temperatures for the QF kept in the refrigerator were worse than keeping it constantly at the temperature recommended by food safety agencies for QF. Furthermore, the mean comparison of estimates of the time-temperature equivalent indicator previously developed by French researchers showed similar behavior to those observed for RPI. Finally, statistical analysis showed that Tambient was the factor with the highest impact on refrigerator performance because of its impact on the sample temperature increase during door openings and when exposed to ambient temperature during product use. This highlights the need to reduce the time for product temperature recovery by improving the compressor operation logic. Also important are consumer behavior changes such as a reduction in product exposure to ambient temperature and in the door opening duration and frequency. PRACTICAL APPLICATION: This study demonstrated how a quantitative tool (RPI) can assess refrigerator preservation performance. Although the findings presented can be applied to any cold chain segment, the data used was collected for its weakest link, the domestic refrigerator. Surveys show that 77% of them operate above the recommended 4°C. The RPI methodology is ready for use by refrigerator designers to assess performance improvements possible by modifications of the compressor operation logic. Moreover, it can be integrated into smart-hubs monitoring the frequency and duration of refrigerator door openings to inform consumers when their habits are compromising the preservation performance of the refrigerator.

Beyond the Urban Kitchen: Refrigeration and Domesticity across Australia and the Pacific Islands, 1920s–1940s

Abstract Histories of the rise of domestic refrigeration conventionally situate the appliance within the urban household. An emphasis on the spread of electrification and notions of idealized femininity, abundance, and scientific home management together attribute an emblematic “Americanness” to the refrigerator. Moving beyond the confines of the urban kitchen to rural and tropical regions of Australia and across the island Pacific, this article examines the appeal and influence of the home appliance in areas remote from reliable or affordable electricity, as well as from accessible supplies of perishable foods produced elsewhere. In such locations the refrigerator was understood differently, centering ideals of white settler self-sufficiency, masculine mastery of the environment, and notions of colonizing capacity. Examining the early history of this appliance in these places also reveals how technological influences and cultural aspirations moved between Australia and the islands and vice versa, intensifying in the immediate aftermath of World War II. In repositioning the refrigerator through such engagements and entanglements, this article offers new insights into patterns and practices of colonial domesticity, provisioning, and consumption.

Experimental investigation of the effect of phase change material on backup time and equivalent energy consumption of domestic refrigerator

Load shedding is a significant problem in rural areas. During a power outage, the cabin temperature of a refrigerator increases owing to the heat gain. In practice, a door should be opened to load and unload refrigerator products, particularly when the power failure period is longer. The use of a phase-change material (PCM) in the refrigerator cabin restricts the increase in temperature and provides a backup time that reduces energy consumption. Door-opening tests are essential during a power cut-off time to investigate the reduction in backup time owing to door openings. This article presents an experimental investigation on the influence of PCM masses of potassium chloride (KCl), sodium chloride (NaCl), and sodium fluoride (NaF) dissolved in water on the backup time and equivalent energy consumption of a domestic refrigerator for closed and open doors according to the standards IS 1476 and IEC 62552:2015. The backup time of closed-door tests was significantly increased by the PCM for all masses, i.e., between 15 and 200 min in absolute terms and between 14% and 182% in relative terms. The backup time for the closed-door tests was 1.8–1.03 times longer than that for the door-opening tests. The backup time of door-opening tests decreased significantly owing to heat entering the cabin for all masses, i.e., between 50 and 10 min in absolute terms and between 45.45% and 3.23% in relative terms. The equivalent energy consumption of a refrigerator decreased with an increase in PCM mass. In closed-door tests, it varied from 0.55 to 0.41 kWh.6-1 h for the 0–1.75 kg mass of all tested PCMs. In the door-opening tests, the equivalent energy consumption increased owing to door opening. The equivalent energy consumption for the door-opening tests was 1.12–1.02 times larger than that for the closed-door tests.

Psychoacoustic model for detecting the sensation of impulsivity in acoustic signals from refrigerators

This study investigates the perception of impulsivity in audio signals specifically caused by thermal expansion (cracking noise) in domestic refrigerators. It employs a multifaceted approach encompassing an analysis of sensitivity to impulsive events, an assessment of the prominence of impulse signals, and a correlation analysis of these data. The investigation revealed different responses to various sound samples, highlighting subjective variations. Using linear regression, correlation analysis demonstrated a robust and positive relationship (Pearson correlation coefficient of 0.851) between perceived impulsivity and the Impulsivity Prediction Model (IPM). This alignment underscores the reliability of the developed IPM in capturing and predicting subjective perceptions of low-amplitude transient signals. Comparisons between groups of participants, conducted using both Analysis of Variance (ANOVA) and t-tests, explored potential disparities related to gender, age, and acoustic knowledge. The results indicated no statistically significant differences in the perception of impulsivity concerning gender, age groups, or acoustic knowledge. In conclusion, this study provides insights into the perceptual aspects of impulsivity in audio signals from home refrigerators, specifically addressing thermal expansion noises, and establishes the reliability of the Impulsivity Prediction Model (IPM) as a tool for objective assessment. The congruence between subjective judgments and objective metrics enhances the applicability of IPM in diverse fields, from acoustic engineering to psychoacoustic research.

Viability of Metagonimus romanicus (Ciurea, 1915) metacercariae after physico-chemical treatments

Digenean (Heterophyidae) trematodes include several zoonotic species such as the genus Metagonimus (Katsurada, 1912). Metagonimus romanicus (Ciurea, 1915) is a species widely distributed in Europe, whose metacercariae can be found on cyprinoids from the River Danube in Hungary. The aim of the study was to measure the viability of Metagonimus romanicus metacercariae by physical (freezing, heating, desiccation) and chemical (acetic acid and NaCl solutions) treatments. The methods were chosen as a model for procedures commonly used in traditional food preservation (such as freezing, salting, pickling and smoking) to measure the survival rate of metacercariae under different conditions. Most physical treatments (freezing of metacercariae at −20 °C, keeping them at 40 °C and 60 °C and desiccation) and chemical treatments (2.5%, 5%, 10% acetic acid solution and 5% and 10% NaCl solution) killed the metacercariae in a relatively short time (from 30 min to 6 days depending on the treatment) so their effects eliminated the risk of zoonotic infection. On the other hand, the metacercariae survived at room temperature and at 4 °C up to one month. Therefore, storing unprepared fish in domestic refrigerators cannot prevent infection with metacercariae in humans.

Framework for accurate estimation of freezing time and convective heat transfer coefficient for freezing of a food product in domestic refrigerator: a numerical and simulation modeling approach

Framework for accurate estimation of freezing time and convective heat transfer coefficient for freezing of a food product in domestic refrigerator: a numerical and simulation modeling approach

EXPLORACIÓN DE LA MEZCLA RE170/R600: MEJORA DE LA EFICIENCIA COMO ALTERNATIVA AL R600a

The utilization of alternative mixtures to R600a has been extensively explored across various applications, showcasing their potential to enhance the energy efficiency of isobutane in domestic refrigerators and standalone commercial appliances while maintaining comparable thermodynamic characteristics and operational performance parameters. Among these mixtures, those composed of a significant proportion of R600 (butane) and a small portion of secondary refrigerant have emerged as the most promising. However, many secondary refrigerants in these blends are synthetic. RE170 (dimethyl ether or DME), a non-fluorinated and natural refrigerant, has emerged as a particularly promising candidate for blending with R600. This paper presents an experimental analysis of the RE170/R600 refrigerant mixture as an alternative to R600a. For that purpose, a simple compressor highly equipper test bench was used, in which the mixture was analyzed at a composition range varying from 2.5/97.5%w to 27.5/72.5%w at steps of 2.5%. Results show COP increments up to 19.3% respect R-600a and VCC and that low required DME matches the one obtained by R600a. RE170/R600 has been demonstrated to be a long-term superior efficiency mixture.

Study of piston offset inhibition method based on the biased center port

The linear compressor is one of the main energy-consuming components in domestic and space refrigeration systems. Due to the asymmetric leakage in the clearance, the piston offset unavoidably causes the piston to deviate from its designed equilibrium position and worsens the compressor performance. In this paper, a new method is proposed to inhibit the piston offset. A biased center port is employed to direct gas from the back chamber to the front at the position close to the back chamber to balance the pressure on the two sides of the piston. To verify this method, a numerical simulation was performed to calculate the mass flow through the clearance and center port channel, and the average pressure difference across the piston. An experimental bench was established to compare the offset of the structures with no center port, unbiased center port and biased center port. Results show that the biased center port can almost eliminate the piston offset at the designed operating condition.

Which domestic refrigerator temperatures in Europe? - Focus on shelf-life studies regarding Listeria monocytogenes (Lm) in ready-to-eat (RTE) foods

Listeria monocytogenes (Lm) is a pathogenic bacteria able to grow at refrigerated temperatures, widely distributed in the environment. This bacteria is susceptible to contaminate various food products of which refrigerated ready-to-eat foods (RTEF) may pose a risk for public health. In Europe, food business operators (FBOs) shall ensure that foodstuffs comply with the relevant microbiological criteria set out in the Regulation (EC) N°2073/2005. Food safety criteria for Lm are defined in RTEF throughout their shelf-life. FBOs should implement studies to demonstrate that the concentration of Lm does not exceed 100 CFU/g at the end of the shelf-life, taking into account foreseeable conditions of distributions, storage and use, including the use by consumers. However, this last part of the cold chain for food products is the most difficult to capture and control.For this purpose, the European Union Reference Laboratory for Lm (EURL Lm) launched an inquiry to its National Reference Laboratory network and reviewed the scientific literature from 2002 to 2020. The outcomes were integrated in the technical guidance document of the EURL Lm to assess shelf-life of RTEF which resulted in the recommendation to use 10 °C as the reference temperature to simulate the reasonably foreseen storage conditions in domestic refrigerators.

Report on the establishment of the safe shelf life of certain ready‐to‐eat foods, sliced and prepacked in retail, in relation to the risk of Listeria monocytogenes

Abstract The Barcelona Public Health Agency (ASPB) asked the Scientific Advisory Committee on Food Safety for an opinion on the safe shelf life of Listeria monocytogenes in certain products (cheeses, cooked meats, including pâtés, and cured meats) sliced and prepackaged prior to retail sale. In order to assess in which cases or under which conditions ready‐to‐eat foods under study may promote the growth of pathogenic microorganisms during their shelf life, the methodology proposed by EFSA (2020) was used. In addition, the predictive model of growth / non‐growth boundaries, based on the gamma concept approach, was applied. To carry out this assessment, the ASPB provided a total of 90 samples (32 in 2020 and 58 in 2021) divided into 4 categories of ready‐to‐eat foods: cheese, cooked ham, pâté / foie and cured ham. In all cases, the food was sliced or cut into portions in retail establishments of the city of Barcelona, and packaged in different formats: vacuum‐packed, in a heat‐sealed or shrink‐wrapped tray, or wrapped in film. The results of the evaluation indicated that the ready‐to‐eat pre‐packaged foods evaluated for the group of cheeses, cooked ham, pâtés and foie required the indication of a “use by” date, as the handling conditions expose the product to a potential L. monocytogenes contamination and the pH and aw (water activity) characteristics associated with these products support its growth. Considering a reasonably foreseeable scenario in relation to storage temperature conditions in retail (2 days at 5°C) and in a domestic refrigerator (5 days at 9.5°C), the safe shelf life of the products that would more favour the growth of L. monocytogenes would be between 4.5 and 4.9 days (corresponding to the 5th and 10th percentile, respectively). This estimate is the result of a conservative approach that provides a margin of safety to the outcome of the evaluation.

Polymer‐based supporting materials and polymer‐encapsulated phase change materials for thermal energy storage: A review on the recent advances of materials, synthesis, and characterization techniques

AbstractPhase change materials (PCMs) can be classified as smart materials having its applications in varied fields like domestic and commercial refrigerators, solar absorption chillers, air conditioning, free and radiative cooling, solar air heaters, solar stills, solar absorption cooling, electric and electronic devices for cooling purposes and in textiles. Here, in this review, the various polymer‐based and encapsulated PCMs used for fulfilling the above applications are discussed along with their varied synthesis/fabrication methods. Furthermore, chemical characterization is discussed by FTIR for understanding the chemical structure along with functional groups present in the materials. The thermogravimetric analysis (TGA) is also critically discussed for understanding the thermal stability of the Polymer PCM or the phase change composites and the latent heat of PCM melting was also explored by differential scanning calorimetry (DSC) for various PCM which gives insight into the thermal energy storage capability and property. The inbuilt surface structure of the polymer PCM was also tried to be investigated by scanning electron microscopy (SEM) which when understood gives a clear picture about the structure–property relationship.Highlights Polymeric supporting materials and polymer encapsulation on PCM were reviewed. The materials used and the synthesis of polymeric PCM were studied in depth. Chemical characterization was reviewed for chemical structure. Thermal stability checks by TGA and latent heat prediction was done by DSC. Morphology was reviewed using SEM for the structure–property relationship.

EXPERIMENTAL STUDY OF DOMESTIC REFRIGERATOR BY USING EVAPORATIVE CONDENSER

Refrigerator has become an essential commodity rather than luxury item. It is one of the home appliance ukkigg, vapour compression cycle in it process. Performance of this system becomes main issue and many researches are still ongoing to evaluate and improve efficiency of the system. This study presents effect of evaporative condenser on COP of domestic refrigerator. The purpose of this article is to compare the COP of refrigerator by using air cooled condenser and evaporative condenser of same length and same diameter. This experiment is carried out on domestic refrigerator (185 ikr4 test rig. In this study, an innovative, evaporative condenser for residential refrigerator was introduced. A yaw compression cycle incorporating the proposed evaporative condenser was tested to evaluate the cycle performance. To allow for evaporative cooling, sheets of cloth were wrapped around condenser to suck the water sprayed on it. The thermal properties at the different points of the refrigeration cycle were measured for typical operating conditions. Further to compare both the condensers some parameters like condenser outlet temperature, evaporator inlet temperature, power consumption have taken. After investigation it was found that evaporative condenser may replace the air cooled condenser from domestic refrigerator KEYWORDS: Refrigerator, Condenser, Evaporator, COP, Refrigerating Effect, Compressor.

LOW-COST OPERATING LPG REFRIGERATOR SYSTEM

The study explores the use of liquefied petroleum gas (LPG) as a refrigerant in domestic refrigerators to provide continuous refrigeration in areas without steady electricity supply. LPG, consisting of propane, butane, and isobutene, is cost-effective and environmentally friendly with no Ozone Depletion Potential or Global Warming Potential. The experiment compared the performance of an LPG-based refrigerator to one using R134a, finding LPG to be more efficient. By analyzing the refrigeration effect over time, the study determined the optimum cooling effect based on valve and capillary tube settings. LPG undergoes a phase change in the capillary tube, resulting in a drop in pressure and temperature, allowing it to produce a refrigerating effect. The Coefficient of Performance (COP) of an LPG refrigerator was found to be higher than a traditional refrigerator. Overall, using LPG as a refrigerant in refrigerators can be a sustainable and environmentally friendly solution for regions with unreliable electricity access. Key Words: LPG, REFRIGERATOR, REFRIGERANT, OZONE DEPLETION POTENTIAL.

Phase Change Materials (PCM) for a Zero-carbon Food Preservation Technology in Remote Areas

Abstract Phase Change Materials (PCM) are thermal storage materials that are capable of storing renewable energy and improve the performance of a solar cooling system. Since solar power is not consistent everywhere and the operating conditions of cooling systems are varying, a specific study is needed to implement this principle for a particular location. This research work aims at developing small-scale solar domestic refrigerator and freezer systems to work with PCMs and solar energy. The software, System Advisor Model is used to select the PV system for the location. An experimental setup of a 210-litre refrigerator and a 250-litre chest freezer with PCM cladding is used. The quantity of low-temperature PCM was varied, and the energy efficiency of the system, temperature distribution inside the refrigerated space, and on-off cycles of the compressor were studied to ensure its technical feasibility. The results from the study showed that the use of PCM could run the system during non-sunshine hours with an 8-15% reduction in energy consumption. The pulldown time was promising, and the off-cycle time of the compressor was long, which ensures that the system can work at the desired temperature during the off-sunshine hours. The temperature distribution inside the freezer and food compartments of the refrigerator for various quantities of PCM was found to be from -14 to -16°C and from 1 to 8°C, respectively. Moreover, the calculated total equivalent warming impact was 15-60% lower than the conventional system. A detailed study on the economic benefits and risk analysis can be conducted to mature the technology