Refrigerator Freezer Research Articles

Investigation of a flexible triple-evaporator domestic refrigerator/freezer with R600a with integrated economization

Domestic refrigerator/freezers account for approximately 6 % of all energy consumption around the globe and mainly rely on vapor compression cycles to operate. Researchers have investigated alternative cycle architectures such as dual-loop cycles and parallel circuit cycles to improve their efficiencies. Despite the demonstrated energy saving potential of these advanced cycles, additional implementation costs are often not justifiable. However, to meet forthcoming stricter energy standards while ensuring flexible multi-temperature operation of domestic refrigerator/freezers, advanced cycle architectures are needed. In this paper, a state-of-the-art bypass circuit cycle triple-evaporator domestic refrigerator freezer with R-600a and a reciprocating compressor has been used as the baseline cycle investigate an alternative cycle configuration. Specifically, this work presents a two-stage vapor-injected cycle with a multi-evaporator system to enable energy savings and cost-effectiveness. The cycle establishes two separate evaporation temperatures to better match the cabinet temperature of fresh food and freezer compartment. The reduced difference between cabinet temperature and its evaporation temperature decreases the irreversibilities in the heat exchanger and improves overall system efficiency. Moreover, the addition of the economization line from the medium temperature evaporator reduces the compressor work. To capture the complex transient behavior of both the baseline system and proposed cycle architecture with their control strategies, a dynamic model has been developed and validated with experimental data. The validated dynamic model with the baseline cycle was modified to consider the two-stage vapor-injected cycle and its control logic, and simulation results yielded up to 13 % energy consumption reduction with respect to the baseline system.

Effect of rapid freezing technology on quality changes of freshwater fish during frozen storage

The impacts of pre-frozen with −80 °C liquid nitrogen spray freezer (LNF), −80 °C refrigerator freezer (RF), and −30 °C micro-freezer (MF) on the freezing rate, physical and chemical properties and microscopic structures of freshwater fish (grass carp, tilapia and bighead carp) stored at −18 °C (14 days) were evaluated. LNF and MF were effective in shortening the entire freezing period and their muscle tissue microscopic structures were more homogeneous and thicker than the RF group, also with smaller and more regular ice crystal. Additionally, the LNF-treated samples had good water holding capacity and textural characteristics and significantly delayed changes in immobilized water content, effectively suppressing the increase in L* values in grass carp samples (p < 0.05). However, MF was not as effective as LNF and RF in inhibiting the formation of TBARS and TVBN. In conclusion, LNF played a more positive role in quality retention of freshwater fish.

Effect of Freezing On Some Morphometric Features of Planiliza Abu ( Hekel,1843)

The present study attempts to determine the effect of freezing for different periods on preserved bodies of fish in the laboratory to keep for the research and diagnosis of taxonomic studies and not for consumption. It also endeavors to identify the effect of freezing on some morphometric features of the preserved bodies of fishes. Planiliza abu fish were used to conduct the present study. Fish were frozen by regular freezing in the home refrigerator freezer with temperatures reaching four degrees centigrade below zero. Freezing time is distributed over four months; biometric measurements of frozen fish have been taken in these periods represented by body total length, Standard length, and Head length in centimeters using a ruler vernier caliper in addition to body weight in grams by using a scale. Statistical data analysis for this experiment has been conducted to investigate the resulting facts of freezing periods and the effect of differences in freezing periods on these biometric measurements using Duncan's new multiple range test and Levene's test. Results showed no apparent significant differences related to the size in total length and standard length and weight, While measuring head length showed important characteristics of frozen fish, especially in the first and third month of the experiment. Most of the sources that deal with such research patterns are concerned with the freezing of fish intended for food and human consumption, and few of these studies are concerned with research freezing, such as preserving frozen fish specimens for analysis, even for some time. Attention to the importance of freezing for research studies related to fish because of the susceptibility of its meat to rapid deterioration, and therefore, may give wrong diagnostic results if the survey is between species from the same family or a diagnostic and taxonomic study between many species belonging to different families. Keywords: Body measurements, Coastal fish, External appearance, Ice crystals, Preservation.

Nutritional, sensory, and storage evaluation of Indian flatbread supplemented with quinoa and pearl millet flour

AbstractThe purpose of present study is to develop a nutritionally enriched Indian flatbread using nutritionally balanced crops. In this study, the whole wheat meal was used as a control and in formulations it was supplemented with quinoa (10%–40%), pearl millet (15%), and potato (5%) flour. The prepared formulations were evaluated for their chemical, physical, microstructural, texture, pasting, and sensory properties. Further, the shelf life of partially baked and packed flatbread at low temperature was also studied. The protein content of formulated flatbread increased from 7.30% to 8.12% with increase in percentage of quinoa flour from 10% to 40%. The pasting properties of composite flour showed a significant (p &lt; .05) reduction in peak, breakdown, trough, final, and setback viscosities. However, change in pasting behavior had no significant effect on dough handling, and the composite dough was smooth and sticky, and flatbread made with up to 30% quinoa flour showed full puffing. Color attributes of enriched flatbread showed a darker color than control, however, it was preferred by the panelists up to the optimum level of 30% quinoa flour. Scanning electron microscopy results indicated that the addition of quinoa and pearl millet flour destroyed the gluten network structure in the dough. Storage studies indicated shelf life of 10 days of partially baked and packed flatbread in a refrigerator freezer. The flatbread with formulation containing 50% whole wheat meal, 30% quinoa flour, 15% pearl millet flour, and 5% potato flour was found to be overall accepted by the consumer.Practical ApplicationsThe present study will lead to the development of nutritional and functional composite flatbread that will open up a new venture for utilizing quinoa and pearl millet flour for reducing malnutrition in developing countries.

Prebiotic Formation of Catalytically Active Dipeptides via Trimetaphosphate Activation.

Short peptides with unique catalytic abilities are regarded as the simplest enzymes possessing great potential as primordial species to take part in the chemical origin of life. However, prebiotic acquisition pathways of catalytically active peptides remain unclear. In this study, a microwave reactor was used to simulate hydrothermal environments, such as hydrothermal vents, either submarine or subaerial environments. A refrigerator freezer was used to make ice pieces that mimic extra-terrestrial ice crystals. Serine (Ser) and histidine (His) were used as examples, and the formation of small functional peptides involving sodium trimetaphosphate (P3 m) activation in an alkaline aqueous solution was investigated under the two typical prebiotic environments mentioned above. The obtained experimental results showed that the targeted small functional peptide Ser-His and its sequence isomer His-Ser could be formed in all simulated environments, even in the presence of disruptive amino acids, such as alanine (Ala), proline (Pro), and aspartic acid (Asp), in the reaction systems. Notably, Pro may have some effect on the chirality of the produced dipeptides by screening the configuration of the amino acids. Owing to the lack of disturbance of N-O migration in the CAPA (His) intermediate, the CAPA intermediate of His is more stable than that of Ser; therefore, His is more easily activated by P3 m to form a dipeptide with His at the N-terminal. The yield of His-Ser is at least about four times that of Ser-His in the two simulated prebiotic environments. Additionally, our work suggests that more types of amino acids can be activated simultaneously by P3 m to produce various dipeptides, which will provide abundant raw materials for the evolution of life molecules.

About the interpretation of the cause of death of a newborn in unusual conditions

The article presents the case of the death of a premature and immature newborn infant, who was placed in the refrigerator freezer after birth. To determine the thanatogenesis of the infant's death, medical documents and case materials were studied, which made it possible to determine the development of pathological processes that led to the death of the newborn, defects in the primary examination of the corpse and shortcomings in the histological examination, limiting judgments about the circumstances of the infant's death.

Identifikasi Kerusakan dan Perbaikan Refrigerator Freezer AR763

Dengan pesatnya perkembangan teknologi saat ini refrigerator freezer (lemari es) sebagai salah satu alat untuk membantu kita dalam menyimpan makanan agar tahan lama. Refrigerasi adalah suatu proses penyerapan panas dari suatu zat atau produk sehingga temperaturnya berada di bawah temperatur lingkungan. Refrigeran adalah zat yang digunakan sebagai fluida kerja dalam proses penyerapan panas. Zat inilah yang bersikulasi dalam mesin refrigrasi, yang menyerap panas dari benda atau udara yang didinginkan, kemudian membuangnya ke udara sekeliling di luar benda atau ruangan yang didinginkan. Dalam penggunaannya refrigenerator sering mengalami kerusakan, sehingga perlu dilakukan analisa kerusakan tersebut. Hasil analisa menunjukan terjadi kerusakan pada refrigerator freezer AR 763, yaitu pada system pendingin terjadi penyumbatan disebabkan refrigerator tidak beroperasi (rusak) dan menyebabkan refrigerant di dalam system membeku yang menyebabkan system tidak bekerja. Selanjutnya filter harus diganti karena filter banyak menyimpan kotoran dan komponen kelistrikannya ada yang rusak seperti thermo fuse dan timer disebabkan batas umur pakai dari komponen.

Expression of Concern on “Vibroacoustic Analysis of a Refrigerator Freezer Cabinet Coupled with an Air Duct”

Expression of Concern on “Vibroacoustic Analysis of a Refrigerator Freezer Cabinet Coupled with an Air Duct”

Recovery of anthocyanins from sour cherry (Prunus cerasus L.) peels via microwave assisted extraction: monitoring the storage stability

Utilization of economical and environmental methods as an alternative process to recover the industrial crops and food products into high-added value compounds is of great significant. In the current study, microwave assisted extraction (MAE) was optimized by response surface methodology (RSM) in order to evaluate the waste of sour cherry as a source of phenolic compounds rich in anthocyanins. The process parameters (microwave power, irradiation time and ethanol solvent concentration) of MAE method were optimized by face centered composite design of RSM. Responses such as total phenolic componds (TPC), total anthocyanin (TA) contents and antioxidant capacity (DPPH) of extracts were measured spectrophotometrically after extractions of samples. The optimized result of MAE was 500 W of microwave power, 90 s of irradation time and 80% ethanol solvent concentration. Antioxidant capacity was tested using by 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical. Chromatographic analysis (HPLC) was also used to measure the concentration of major anthocyanin (cyanidin-3-glucoside) of the samples. Maximum predicted TPC, TA and DPPH yields on optimized conditions were 44.15 mg-GAE/g-FM (mg- gallic acid equivalent per g- fresh matter), 12.47 mg-cyanidin-3-glucoside/g-FM and 69.90 (%, inhibition), respectively. A stability assay under different conditions (light, dark, ambient condition, refrigerator and deep freezer) has been also performed in order to display the stability of bioactivity profile. All of the process parameters were significant at the level of p < 0.0001.

Investigation of Heat Transfer Enhancement in the Refrigerator Freezer via Utilizing Elliptical-Shaped Scars

Investigation of Heat Transfer Enhancement in the Refrigerator Freezer via Utilizing Elliptical-Shaped Scars

Comparative performance evaluation of conventional and condenser outlet split ejector-based domestic refrigerator-freezers using R600a

The objective of this study is to investigate the performance characteristics of an R600a domestic refrigerator-freezer (RF) adopting a condenser outlet split (COS) ejector cycle. Experiments are conducted to measure the performances of conventional and COS ejector-based domestic RFs using R600a. A test bench is used to analyze the pressure lifting effect, mass flow rate variation, and coefficient of performance (COP) improvement with respect to the entrainment ratio (ER). For entire cycle operation at similar cooling capacity condition, the overall COP improvement of the test bench adopting COS ejector cycle over the baseline cycle is 11.4% at the ER of 0.18. Moreover, the COS ejector-based domestic RF is tested to examine its feasibility in actual applications. The COS ejector-based domestic RF with a compressor speed of 1450 rpm exhibits a temperature profile in the freezer compartment that is similar to that of the baseline domestic RF. At similar cooling capacity condition, the energy consumption of the COS ejector-based domestic RF with the compressor speed of 1450 rpm is 10.9% lower than that of the baseline domestic RF, owing to the pressure lifting effect.

Effects of exogenous hormones like acc on germination of lettuce seeds

In order to investigate the effects of different exogenous hormones on the dormancy and germination of lettuce seeds, this paper soaks the lettuce seeds in ACC, GA, CaCl2 and SNP solutions with different concentrations, respectively, observes the quantity of lettuce seeds germinated, calculates the germination rate, and analyzes the optimum concentrations to break the period of dormancy and promote the germination of seeds to increase the germination rate of seeds. Through the observation of lettuce seeds soaked with ACC, GA, calcium chloride and SNP in different time periods, it is found that ACC, GA, calcium chloride and SNP solutions can all promote the germination of lettuce seeds. Lettuce falls within the Lactuca genus, the Asteraceae family. It likes cold climate and the suitable temperature for growth is 15-20°C. If the temperature exceeds 25°C, the high temperature in the leafy head will cause the necrosis and rot and poor growth of interior leaves (Song et al., 2013). The temperature for germination of seeds ranges between 15-20°C. If the temperature is higher than 25°C, the seed coat will not be able to absorb water, affecting the germination (Li et al., 2012). When lettuce is sowed in summer, it needs to be treated at a low temperature. After being soaked, it should be placed in the refrigerator freezer to accelerate germination and should not be sowed until the sprout turns white. Lettuce is rich in protein, sugar, vitamins, minerals and other nutrients. It is popular among consumers due to its crisp texture, fresh taste and fragrance and rich nutrition (Hu and Zhan, 2014). Few research has been conducted on the effects of exogenous hormones on the germination rate of lettuce seeds. This study takes lettuce seeds from the same source as the test material and conducts tests on the germination rate of lettuce seeds, trying to explore the effects of ACC, GA, CaCl2 and SNP solutions with different concentrations on the germination rate of lettuce seeds so as to improve the germination rate.

Vibroacoustic Analysis of a Refrigerator Freezer Cabinet Coupled with an Air Duct

In this study, the vibration and acoustic interactions between the structure and the cavity inside the freezer cabinet were investigated. Thus, a set of numerical and experimental analyses were performed. In the numerical analysis, the acoustic characteristics of the freezer cavity were solved, and the mixed finite element method was then implemented to analyse the coupled behaviour of the cavity with the air duct using the Acoustic Fluid-Structure Interaction (AFSI) technique. In the experimental analyses, an acoustic modal analysis of the freezer cavity and a structural modal analysis of the air duct were performed for the validation process. A good agreement was obtained among the results. Thus, the accuracy of the numerical model was confirmed. The validated models were used for optimizing the design. To solve the noise generation mechanism inside the freezer cabinet, the noise primarily generated by the freezer fan unit was measured under normal working conditions of the refrigerator, and the resonance frequencies were obtained. This information was compared with the normal modes of the air duct, and the overlapping frequencies were identified. To reduce the interaction between the source and the structure, a few design modifications were applied to the air duct. Thus, the structural-borne noise radiating from the air duct into the freezer cavity was reduced.

Kitchen Physics: Lessons in Fluid Pressure and Error Analysis

Although the advent and popularization of the “flipped classroom” tends to center around at-home video lectures, teachers are increasingly turning to at-home labs for enhanced student engagement. This paper describes two simple at-home experiments that can be accomplished in the kitchen. The first experiment analyzes the density of four liquids using a waterproof case and a smartphone barometer in a container, sink, or tub. The second experiment determines the relationship between pressure and temperature of an ideal gas in a constant volume container placed momentarily in a refrigerator freezer. These experiences provide a ripe opportunity both for learning fundamental physics concepts as well as to investigate a variety of error analysis techniques that are frequently overlooked in introductory physics courses.

Effect of defrost heat leakage on freezer temperature rise during periodical defrost cycles in a frost-free refrigerator–freezer with an electric defrost heater

Periodical defrost actions are essential for the frost-free refrigerator–freezer to remove frost on the evaporator and recover its heat transfer performance. However, defrost heat could leak into the freezer and raise its temperature during defrost cycles. In this article, the effect of defrost heat leakage on freezer temperature rise of a frost-free refrigerator–freezer using an electric defrost heater was experimentally investigated. The defrost cycle was subdivided into three stages: heating, melting, and draining. Results show that in the heating stage, little warm air leaked into the freezer due to the obstruction of the frosted evaporator, so freezer temperature hardly rose (by less than 0.1°C/min). In the melting stage, flow area between adjacent fins gradually enlarged with frost melting from the bottom to the top of the evaporator; thus, warm air leaked into the freezer, raising its temperature by 0.6°C/min in average. In the draining stage, the adjacent-fin flow area reached maximum as nearly all the frost had been removed throughout the evaporator; hence, large amount of warm air entered the freezer and raised its temperature by 1.0°C/min. To the best of the author's knowledge, the stage-based acceleration in freezer temperature rise during defrost cycles was covered for the first time.

Transfusion practice in dogs and cats: an Internet-based survey.

To characterize and compare current canine and feline transfusion practices at private referral hospitals (PRH) and veterinary teaching hospitals (VTH), including information regarding blood donor screening; blood product collection, storage, and administration; recipient screening; and monitoring during transfusions. Internet-based survey. Sixty-five board-certified specialist veterinarians, 3 veterinarians, and 5 veterinary technicians from 53 PRH and 20 VTH. A survey was disseminated via email LIST-SERVs; 1 survey response per hospital was included. Survey results revealed that PRH more commonly obtained canine and feline blood products solely from blood banks (P < 0.05) and VTH more commonly used hospital-run donor programs (P < 0.05). Canine cryo-poor plasma was more likely to be stored by VTH compared to PRH (P = 0.018) and VTH were more likely to store canine fresh platelet products for >72 hours (P = 0.046). The use of client-owned canine donors (P = 0.043), administration of precollection 1-deamino-8-d-arginine vasopressin to canine donors (P = 0.041), and storage of blood products in a dedicated refrigerator (P = 0.003) and -20°C or -80°C freezer (P = 0.044) were more common in VTH than PRH. However, the use of a refrigerator freezer (P = 0.001), single bag canine collection systems (P = 0.021), and agglutination cards for feline blood typing (P = 0.032), as well as warming of blood products prior to administration (P = 0.021) were more commonly reported by PRH compared to VTH. Although some transfusion practices including the method and length of storage of blood products, use and screening of blood donors, and administration methods varied between VTH and PRH, most transfusion practices were similar. The information reported from this survey could aid the development of future veterinary transfusion consensus statements.

Study of cold chain management system at Urban Primary Health Centers (UPHCs) of Vadodara city in Western India

Background: Urban Primary Health Centers (UPHCs) have been the backbone for delivering immunization services in urban areas in India. It is thereby important that cold chain system is maintained at these UPHCs. Objective: To assess the cold chain management system at all UPHCs of Vadodara city in western India. Materials and Methods: A cross-sectional observational study was conducted at all 19 UPHCs of Vadodara city run by Vadodara Municipal Corporation. All 19 UPHCs of the entire Vadodara city were assessed for cold chain management system from April 2013 to May 2014. Data collection was done as a part of supportive supervision of Reproductive Maternal Newborn Child Health plus Adolescents (RMNCH+A) program by using structured checklist. Data were entered in Microsoft Office Excel and analyzed using Epi Info software. Descriptive statistics including actual numbers and proportions of the study variables are mentioned. Result: Cold chain equipments including ice-lined refrigerator (ILR) and deep freezer (DF) were functional at all 19 UPHCs. No other vaccines/medicines were stored in ILR or DF in any center. Ice packs were correctly placed at five centers only. Frozen vaccine vial was observed at one site. Conclusion: Cold chain was maintained quite satisfactorily at all the UPHCs of the Vadodara city. However, some logistics and training of cold chain handler needs to be focused as highlighted in the study.

An Experimental Investigation of Door Opening Effect on Household Refrigerator; the Perspective in Bangladesh

In this study presents the experimental investigation of the effects of number of door openings on the energy consumption of a household refrigerator. The experiments were conducted under the different number of door opening conditions. From the test results, energy consumption of refrigerator with door opening was found to increase compared to the same product without door opening. Depending on the number of door opening about 7-30% more energy consumption has been observed as compared to closed door condition. Experimental results also show that the compressor on-off cycling increases by about 2-5 times because of the number of door opening increase which ultimately increases the system loss of the refrigeration system. The test result also proved that the temperature fluctuation inside the cabin is increased with increasing the number of door opening which ultimately damage the quality of the food. If the users in Bangladesh be serious, a significant amount of energy could be saved and reduce the system losses with proper utilizing of the refrigerator freezer.

Performance optimization of dual-loop cycles using R-600a and hydrocarbon mixtures designed for a domestic refrigerator-freezer

A dual-loop cycle for a domestic refrigerator-freezer (RF) has a large energy saving potential because it has a lower compression ratio due to a higher evaporating temperature in the fresh food compartment (R)-operation compared to a conventional refrigeration cycle, as well as individual optimization flexibility for each loop. In this study, optimizations of dual-loop cycles using R-600a and hydrocarbon (HC) mixtures were individually carried out. Each optimization process included both a theoretical analysis and an experimental investigation. The theoretical analysis was conducted to optimize the specifications of cycle components and the HC mixture compositions for each loop. Based on the experimental results, the energy consumptions of the optimized dual-loop cycles using R-600a and HC mixtures were decreased by 14.2% and 18.6%, respectively, compared with that of a bypass two-circuit cycle using R-600a in the same RF platform.

Cost-effectiveness of high-efficiency appliances in the U.S. residential sector: A case study

This paper presents an analysis of the cost-effectiveness of high-efficiency appliances in the U.S. residential sector using cost and efficiency data developed as part of the regulatory process of the U.S. Department of Energy's Appliances and Commercial Equipment Standards Program. These data are presented as a case study in the development of an ‘efficiency technology database’ which can be expanded and published as a resource to other researchers and policy makers seeking scenarios that optimize efficiency policies and forecast their likely impacts on energy demand and greenhouse gas emissions. The use of this data to evaluate cost-effectiveness according to a variety of metrics is demonstrated using the example of one refrigerator–freezer product class. Cost-effectiveness is then evaluated in terms of cost of conserved energy for refrigerators, room air conditioners, water heaters, cooking equipment, central air conditioners and gas furnaces. The resulting potential of cost-effective improvement ranges from 1% to 53% of energy savings, with a typical potential of 15–20%.