Commercial Refrigeration

In this study, the use of R134a and R134a/R1234yf (10/90) refrigerants in a cooling system have been investigated theoretically. The energy, environmental and enviroeconomic analyzes of refrigerants have been performed for a cooling system. The energy performances of refrigerants have been made for different evaporator (between -10 o C and 5 o C) temperatures and a constant condenser (35 o C) temperature. The R134a/R1234yf (10/90) has a higher mass flow rate (26.50%) than R134a. Because R134a/R1234yf (10/90) has a lower refrigerating effect (evaporator enthalpy difference) than R134a. The R134a/R1234yf (10/90) has slightly higher compressor energy consumption (nearly 2.94%) than R134a, and so the COP of R134a has slightly (nearly 2.85%) higher than R134a/R1234yf (10/90). When compared to R134a, it is seen that the R134a/R1234yf (10/90) significantly reduces discharge temperature (about 16%). The environmental and enviroeconomic result values of R134a/R1234yf (10/90) are slightly higher than R134a. However, even the slight differences are significant to the evaluation of the environmental impact of refrigerants. It is seen that the wind energy source has the lowest environmental and enviroeconomic value and so the wind energy is the best environmentally friendly energy source according to the other energy sources.

CO2 transcritical booster architectures are widely analyzed to be applied in centralized commercial refrigeration plants in consonance with the irrevocable phase-out of HFCs. Most of these analyses show the limitations of CO2 cycles in terms of energy efficiency, especially in warm countries. From the literature, several improvements have been proposed to raise the booster efficiency in high ambient temperatures. The use of economizers is an interesting technique to reduce the temperature after the gas cooler and to improve the energy efficiency of transcritical CO2 cycles. The economizer cools down the high pressure’s line of CO2 by evaporating the same refrigerant extracted from another point of the facility. Depending on the extraction point, some configurations are possible. In this work, different booster architectures with economizers have been analyzed and compared. From the results, the combination of the economizer with the additional compressor allows obtaining energy savi...

In this work the experimental results obtained from a direct expansion refrigerating plant converted into an indirect plant, are presented and discussed in terms of energy consumption for a commercial refrigerating unit plugged to a medium temperature cabinet. Refrigerants used in the analysis are R134a for direct system, and R134a, R152a and R1234ze(E) for indirect system. The evaluation has been performed at laboratory conditions using three different heat rejection levels: 43.6, 32.8 and 23.3ºC keeping constant the environmental conditions in the cabinet (25ºC; 55%). From the experimental tests performed during 24 hours, it has been demonstrated that the adoption of an indirect configuration results in an increment of the total energy consumption of the refrigerating plant regardless the refrigerant adopted. The average increment registered was 21.8% for R134a, 18.7% for R152a and finally 27.2% for R1234ze(E). The adoption of an indirect system also reduces the refrigerant mass charge of the facility up to 62% depending on the refrigerant used.

This work presents the experimental evaluation of R-513A (GWP=573) and R-450A (GWP=547) as R-134a (GWP=1301) drop-in replacements and as R-507A (GWP=3987) retrofits in a commercial direct expansion refrigeration system for medium temperature applications (2ºC). The evaluation covered 24-hour tests using a single-stage cycle with semi-hermetic compressor, an electronic expansion valve customized for each refrigerant and a commercial vertical cabinet with doors placed inside a climatic chamber. The tests were performed at three water dissipation temperatures (23.3, 32.8 and 43.6ºC). Experimental results indicate that R-513A and R-450A can operate with R-134a plants, with increments in energy consumption between-1.6 to +1.2% for R-513A and from +1.3 to +6.8% for R-450A, whereas in comparison with R-507A, R-513A offered reductions in energy consumption between 4.4 to 8.2% and R-450A between 0 to 3.3%. The paper analyses the modification of the operating pressures/temperatures and the energy indicators using the four refrigerants.

Commercial refrigeration has undergone significant changes in recent years. In the European market, this is mainly due to the F-Gas Regulation (EU 517/2014). F-Gas affects in great measure to commercial centralized refrigeration systems for supermarkets with cooling load higher than 40kW, where the use of refrigerants with GWP higher than 150 will be banned in 2022. As a long-term solution, CO 2 has been adopted as unique refrigerant in almost all Europe overcoming the main technology hurdles. The use of booster systems in supermarkets allow covering simultaneously the medium and the low temperature services with different cycle configurations depending on the environmental conditions. The use of the desuperheater between both compression stages is a simple method to reduce the temperature at the suction port of the medium-temperature compressors improving its efficiency and therefore reducing its power consumption. The benefits of using this arrangement in terms of power consumption, discharge temperature, optimum pressure and COP, are experimentally evaluated and discussed in this work with increments in COP up to 7.05 %.

HFC refrigerants. However, this is expected to change soon. a concern due to the increased number of components, connections, and still large amount of refrigerant-containing piping. Secondary coolant systems offer another alternative that can provide more significant reductions in charge and leakage rate. Introduced in the U.S. in 1996, medium-temperature secondary coolant systems using propylene glycol are gaining wider acceptance and represent a significant portion of business with more than 500 systems installed, primarily in the U.S., with a small percentage of installations in Canada and Mexico. Today, these systems are primarily applied not only for the benefits of HFC charge reduction, but enhanced product quality

Based on laboratory investigations in FY16 for R-22 and R-410A alternative low GWP refrigerants in two baseline rooftop air conditioners (RTU), we used the DOE/ORNL Heat Pump Design Model to model the two RTUs and calibrated the models against the experimental data. Using the calibrated equipment models, we compared the compressor efficiencies and heat exchanger performances. An efficiency-based compressor mapping method was developed, which is able to predict compressor performances of the alternative low GWP refrigerants accurately. Extensive model-based optimizations were conducted to provide a fair comparison between all the low GWP candidates by selecting their optimal configurations at the same cooling capacity and compressor efficiencies. The results illustrate that all the R-22 low GWP refrigerants will lead to slightly lower EERs. ARM-20B appears the best R-22 replacement due to its compatible EER and compressor displacement volume. However, at higher ambient temperatures, ARM-20A is the better candidate because its pressure ratio increases more slowly with the ambient temperature than the other refrigerants, which mitigates the degradation in the compressor efficiencies. In contrast, all R-410A low GWP candidates will result in similar or better efficiencies than R-410A. R-32 has the best EER and heat transfer performance while requiring the smallest compressor. However, R-32's pressure ratio increases the most with ambient temperature, which impairs its high ambient performance and may require more modifications on the compressor and system. R-452B appears to be the most suitable drop-in replacement, as it uses the closest compressor displacement volume and achieves the same efficiency as R-410A.

This work presents the experimental evaluation of energy consumption and refrigerant charge reduction when a commercial direct expansion refrigeration system is converted into an indirect system. The evaluation (with R-134a and R-507A) used a commercial cabinet with doors for medium temperature and a single-stage refrigeration cycle using a semi-hermetic compressor and electronic expansion valve; 24-h energy consumption tests were performed at laboratory conditions for each refrigerant and configuration at three heat rejection levels (23.3, 32.8 and 43.6 °C), maintaining an average product temperature inside the cabinet of 2 °C. The work analyses the impact of the conversion on temperature and pressure indicators, as well as, in the energy performance of each element. For R-134a the refrigerant charge was reduced in a 42.9%, but the energy consumption rose by 22.0%–22.8%; for R-507A the charge reduction was of 32.8% with an increase in energy consumption of between 27.7% and 38.7%.

In this study, first energy and exergy analysis for supermarket cooling applications having high refrigerant capacity are examined and next, based on these analyses and different gases used, CO 2 emission effect caused by these systems have been evaluated according to two parameters. The study investigated thermodynamic and environmental effects at medium (10/0 • C) and low (−35/0 • C) evaporation temperatures by reference to a supermarket cooling application with a 4000-5000 m 2 store size. The study revealed that, refrigerant R-404A is proved to have far worse results than R-22, and proposed alternatives for R-404A, the R-407C and R-152a refrigerants have better average exergetic efficiency ratio, 8.73% and 13.58% respectively. In addition, according to the TEWI and ICF parameters, emission potentials of these refrigerants were found to be lower being average 27.49% and 25.47 and 34.1% and 51.19 respectively. The study concluded with assessment of how the exegry and environmental effect analyses impact system preference.

In this work the experimental results obtained from a direct expansion refrigerating plant converted into an indirect plant, are presented and discussed in terms of energy consumption for a commercial refrigerating unit plugged to a medium temperature cabinet. Refrigerants used in the analysis are R134a for direct system, and R134a, R152a and R1234ze(E) for indirect system. The evaluation has been performed at laboratory conditions using three different heat rejection levels: 43.6, 32.8 and 23.3ºC keeping constant the environmental conditions in the cabinet (25ºC; 55%). From the experimental tests performed during 24 hours, it has been demonstrated that the adoption of an indirect configuration results in an increment of the total energy consumption of the refrigerating plant regardless the refrigerant adopted. The average increment registered was 21.8% for R134a, 18.7% for R152a and finally 27.2% for R1234ze(E). The adoption of an indirect system also reduces the refrigerant mass charge of the facility up to 62% depending on the refrigerant used.

This work presents the experimental evaluation of energy consumption and refrigerant charge reduction when a commercial direct expansion refrigeration system is converted into an indirect system. The evaluation (with R-134a and R-507A) used a commercial cabinet with doors for medium temperature and a single-stage refrigeration cycle using a semi-hermetic compressor and electronic expansion valve; 24-h energy consumption tests were performed at laboratory conditions for each refrigerant and configuration at three heat rejection levels (23.3, 32.8 and 43.6 °C), maintaining an average product temperature inside the cabinet of 2 °C. The work analyses the impact of the conversion on temperature and pressure indicators, as well as, in the energy performance of each element. For R-134a the refrigerant charge was reduced in a 42.9%, but the energy consumption rose by 22.0%–22.8%; for R-507A the charge reduction was of 32.8% with an increase in energy consumption of between 27.7% and 38.7%.

This work presents the experimental evaluation of energy consumption and refrigerant charge reduction when a commercial direct expansion refrigeration system is converted into an indirect system. The evaluation (with R-134a and R-507A) used a commercial cabinet with doors for medium temperature and a single-stage refrigeration cycle using a semi-hermetic compressor and electronic expansion valve; 24-h energy consumption tests were performed at laboratory conditions for each refrigerant and configuration at three heat rejection levels (23.3, 32.8 and 43.6 °C), maintaining an average product temperature inside the cabinet of 2 °C. The work analyses the impact of the conversion on temperature and pressure indicators, as well as, in the energy performance of each element. For R-134a the refrigerant charge was reduced in a 42.9%, but the energy consumption rose by 22.0%–22.8%; for R-507A the charge reduction was of 32.8% with an increase in energy consumption of between 27.7% and 38.7%.

CO2 transcritical booster architectures are widely analyzed to be applied in centralized commercial refrigeration plants in consonance with the irrevocable phase-out of HFCs. Most of these analyses show the limitations of CO2 cycles in terms of energy efficiency, especially in warm countries. From the literature, several improvements have been proposed to raise the booster efficiency in high ambient temperatures. The use of economizers is an interesting technique to reduce the temperature after the gas cooler and to improve the energy efficiency of transcritical CO2 cycles. The economizer cools down the high pressure’s line of CO2 by evaporating the same refrigerant extracted from another point of the facility. Depending on the extraction point, some configurations are possible. In this work, different booster architectures with economizers have been analyzed and compared. From the results, the combination of the economizer with the additional compressor allows obtaining energy savi...

Commercial refrigeration has undergone significant changes in recent years. In the European market, this is mainly due to the F-Gas Regulation (EU 517/2014). F-Gas affects in great measure to commercial centralized refrigeration systems for supermarkets with cooling load higher than 40kW, where the use of refrigerants with GWP higher than 150 will be banned in 2022. As a long-term solution, CO 2 has been adopted as unique refrigerant in almost all Europe overcoming the main technology hurdles. The use of booster systems in supermarkets allow covering simultaneously the medium and the low temperature services with different cycle configurations depending on the environmental conditions. The use of the desuperheater between both compression stages is a simple method to reduce the temperature at the suction port of the medium-temperature compressors improving its efficiency and therefore reducing its power consumption. The benefits of using this arrangement in terms of power consumption, discharge temperature, optimum pressure and COP, are experimentally evaluated and discussed in this work with increments in COP up to 7.05 %.

In this work the experimental results obtained from a direct expansion refrigerating plant converted into an indirect plant, are presented and discussed in terms of energy consumption for a commercial refrigerating unit plugged to a medium temperature cabinet. Refrigerants used in the analysis are R134a for direct system, and R134a, R152a and R1234ze(E) for indirect system. The evaluation has been performed at laboratory conditions using three different heat rejection levels: 43.6, 32.8 and 23.3ºC keeping constant the environmental conditions in the cabinet (25ºC; 55%). From the experimental tests performed during 24 hours, it has been demonstrated that the adoption of an indirect configuration results in an increment of the total energy consumption of the refrigerating plant regardless the refrigerant adopted. The average increment registered was 21.8% for R134a, 18.7% for R152a and finally 27.2% for R1234ze(E). The adoption of an indirect system also reduces the refrigerant mass charge of the facility up to 62% depending on the refrigerant used.

This work presents the experimental evaluation of energy consumption and refrigerant charge reduction when a commercial direct expansion refrigeration system is converted into an indirect system. The evaluation (with R-134a and R-507A) used a commercial cabinet with doors for medium temperature and a single-stage refrigeration cycle using a semi-hermetic compressor and electronic expansion valve; 24-h energy consumption tests were performed at laboratory conditions for each refrigerant and configuration at three heat rejection levels (23.3, 32.8 and 43.6 °C), maintaining an average product temperature inside the cabinet of 2 °C. The work analyses the impact of the conversion on temperature and pressure indicators, as well as, in the energy performance of each element. For R-134a the refrigerant charge was reduced in a 42.9%, but the energy consumption rose by 22.0%–22.8%; for R-507A the charge reduction was of 32.8% with an increase in energy consumption of between 27.7% and 38.7%.

This work presents the experimental evaluation of R-513A (GWP=573) and R-450A (GWP=547) as R-134a (GWP=1301) drop-in replacements and as R-507A (GWP=3987) retrofits in a commercial direct expansion refrigeration system for medium temperature applications (2ºC). The evaluation covered 24-hour tests using a single-stage cycle with semi-hermetic compressor, an electronic expansion valve customized for each refrigerant and a commercial vertical cabinet with doors placed inside a climatic chamber. The tests were performed at three water dissipation temperatures (23.3, 32.8 and 43.6ºC). Experimental results indicate that R-513A and R-450A can operate with R-134a plants, with increments in energy consumption between-1.6 to +1.2% for R-513A and from +1.3 to +6.8% for R-450A, whereas in comparison with R-507A, R-513A offered reductions in energy consumption between 4.4 to 8.2% and R-450A between 0 to 3.3%. The paper analyses the modification of the operating pressures/temperatures and the energy indicators using the four refrigerants.

The application of closed refrigerated multideck display cases (CRDC) and electronic fans is slowly increasing in Brazilians supermarkets, following the international trend. In order to obtain energy savings, this paper reports the results of experimental tests performed in a CRDC according to ISO 23953 to evaluate the influence of (1) environmental conditions, (2) gaps between doors and (3) fans type on the overall performance of a display case. Experimental laboratory tests were performed on two different conditions of temperature and relative humidity of the ambient air (Tamb=25°C; amb=60% and Tamb=27°C; amb=70%), with electromagnetic and electronic fans, and with and without gaps between doors. The analysis and discussion of experimental results include the comparison of compressor energy consumption, total heat load, total condensed water collected on defrost periods and air and product temperatures. The experimental data analysis provides valuable information to set the operative parameters of the CRDC taking into account usual in-store conditions in Brazil.

The application of closed refrigerated multideck display cases (CRDC) and electronic fans is slowly increasing in Brazilians supermarkets, following the international trend. In order to obtain energy savings, this paper reports the results of experimental tests performed in a CRDC according to ISO 23953 to evaluate the influence of (1) environmental conditions, (2) gaps between doors and (3) fans type on the overall performance of a display case. Experimental laboratory tests were performed on two different conditions of temperature and relative humidity of the ambient air (Tamb=25°C; amb=60% and Tamb=27°C; amb=70%), with electromagnetic and electronic fans, and with and without gaps between doors. The analysis and discussion of experimental results include the comparison of compressor energy consumption, total heat load, total condensed water collected on defrost periods and air and product temperatures. The experimental data analysis provides valuable information to set the operative parameters of the CRDC taking into account usual in-store conditions in Brazil.

The research aimed a comparision of behavior for shopping in super market and traditional market for goods in Can Tho city. The sample size of the research was 150 samples which the object is 95 samples of consumers, small business sales is 50 samples and the manager of the supermarket is 5. This paper applied research methods of descriptive statistics and discriminant function, the results showed that some prominent advantages of supermarkets are diversity in good, consistence in price, dynamic promotion. Meanwhile, the Vietnamese traditional market which has still kept some own advantages is competing to supermarket in term of business. You can easily reach a certain traditional market wherever you are in urban or rural. Moreover, going to a close-to-house market gives you chance to meeting neighbors, to bargain; and such things are part of Vietnamese cultural activities. However, the traditional market still keeps some disadvantages like: bad sanitation, uncertain quality of good, untrustworthiness which erode the consumers' favor to it. Ours paper try to analyses such matters and look for a suggestion to raise the relative role of traditional market to modern supermarket. Ours paper try to analyses such matters and look for a suggestion to raise the relative role of traditional market to modern supermarket.