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Effects of refrigerant drop-in (R32/R410) and operating conditions on the performance of a heat pump system.

Number: 2431

Author(s) : ZAMAN M. A., WANG S.

Summary

As the low GWP refrigerants are widely adopted in HVAC&R, the effects of refrigerant drop-in on the system performance need to be evaluated for the system modification and component redesign. Due to the difference in the thermodynamic properties, the low GWP refrigerant drop-in can change system capacity and coefficient (COP); as a result, the system operation might require necessary adjustment for optimum performance.
This work tests the refrigerant drop-in performance (from R410 to R32) in a heat pump system according to the standard EN 14825. The studied heat pump is a refrigerant to water-ethylene glycol (WEG) system using a variable speed scroll compressor, and its designed capacity is 9 KW. Seasonal performance was evaluated under different test conditions, - the combinations of variable condenser WEG outlet temperature (Tcw,o) at different part load with fixed evaporator WEG inlet temperature (Tew,i), to be specific, the test conditions were: Case 1 (Tcw,o= 35-24°C and Tew,i= 10°C), Case 2 (Tcw,o= 55-30°C and Tew,i= 10°C) and Case 3 (Tcw,o= 35-24°C and Tew,i= 0°C). Maintaining the same compressor frequencies resulted in higher heating capacity with R32 during higher part load conditions (100%, 88%, and 54%); however, higher compressor power was consumed due to higher pressure ratios, and the calculated seasonal coefficient of performance (SCOP) was 2% lower than R410A with test case 1. Though similar heating capacity resulted for R32 with lower compressor power, SCOP remained the same as R410A because of higher cycling loss at the lowest part load (15%) during test case 1. Compared to test case 1, the SCOP with R32 during test cases 2 and 3 dropped by 33% and 25%, respectively. Though the pressure ratio with test case 3 was greater than test case 2, compared with test case 1, the compressor operating conditions suffered more during test case 2 with elevated discharge pressure. Thus, this research provides an understanding of operating circumstances and the R32 refrigerant drop-in effect on heat pump operation, which might result in changes to the system design for improved efficiency.

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  • Original title: Effects of refrigerant drop-in (R32/R410) and operating conditions on the performance of a heat pump system.
  • Record ID : 30033130
  • Languages: English
  • Subject: Technology
  • Source: 2024 Purdue Conferences. 20th International Refrigeration and Air-Conditioning Conference at Purdue.
  • Publication date: 2024/07/17

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