Energy assessment of an R134a refrigeration plant upgraded to an indirect system using R152a and R1234ze(E) as refrigerants

Abstract

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.

Drop-in and retrofit refrigerants as replacement possibilities of R134a in domestic/commercial refrigeration and automobile air conditioner applications

“…The fluids R134a, R513A were experimentally tested in a refrigeration test bench by Mota-Babiloni et al [9], their results showed that the power consumption of R513A was greater, the COP was 5% higher, and the cooling capacity was higher than R134a. In the most recent study, Sánchez et al [90] performed experimental analysis from the point of view of the energy impact using R134a, R152a and R1234ze(E) in a commercial glass door cabinet. The total energy consumed for one day with an indirect expansion configuration was increased by 21.8% for R134a, 18.7% for R152a and 27.2% for HFO-1234ze(E).…”

Research on the Application of an HFO1234yf/HFC134a Mixture in a Vehicle Air-Conditioner System with an Internal Heat Exchanger

“…The system performance of HFC152a is similar to that of HFC134a. 7 However, it is not recommended to be used in refrigeration equipment due to flammability. As a natural refrigerant, CO 2 has better performance in refrigeration systems, 8 but the refrigeration equipment needs great changes because CO 2 runs in very high pressure cycles.…”

“…However, due to the higher flammability, explosion may occur with a large charge of hydrocarbons in refrigeration units. The system performance of HFC152a is similar to that of HFC134a . However, it is not recommended to be used in refrigeration equipment due to flammability.…”

Energy assessment and environmental impact analysis of an R134a/R744 cascade refrigeration plant upgraded with the low-GWP refrigerants R152a, R1234ze(E), propane (R290) and propylene (R1270)

“…This arrangement allows reducing substantially the refrigerant's leak rate up to 90% [17] as well as the amount of refrigerant used in the system [18]. However, indirect layout uses a fluid pump and an additional heat exchanger that increases the energy consumption of the refrigerating facility due to the power consumed by the pump and the extra temperature difference required in the secondary fluid cooler [19][20][21].…”