Performance Evaluation of Low Global Warming Potential (GWP) Refrigerants


Refrigerants used in vapor-compression air conditioners and heat pumps are ubiquitous and have a high global warming potential (GWP).


To help reduce the effects these greenhouse gasses have on our atmosphere, companies are developing alternative refrigerants with lower GWP. This research evaluates new, lower GWP refrigerants and compares performance against the standard R-410A refrigerant.



This project, funded by Trane, compares the performance of a unitary heat pump using the industry standard R-410A and a new low GWP refrigerant R-466A.

We tested the performance of the unit at six outdoor air conditions using an environmental control chamber at the Western Cooling Efficiency Center. The unit was instrumented so its performance could be quantified according to the ANSI/AHRI Standard 210/240 and compared at each test point.

We measured the performance of the heat pump with R-410A refrigerant, changed the refrigerant out for the new R-466A, and then retested heat pump performance. The final performance of the unit using R-410A and R-466A was compared using capacity, total power, and coefficient of performance (COP).

The retrofit R-466A lower GWP refrigerant was able to provide similar performance to R-410a.

At higher temperatures the performance was the same while at lower temperatures R-466A capacity and efficiency was slightly lower compared to R-410A. The R-466A refrigerant was also slightly denser and required about 8% more refrigerant charge compared to R-410A.

Global Warming Potential comparison of the tested alternative refrigerant (R-466A) versus the current standard refrigerant (R-410A)


We tested a new refrigerant, R-452B under a variety of conditions and compared the results to the standard refrigerant, R-410A. This refrigerant is claimed to have a 70% smaller GWP than R-410A. R-452B is also a drop-in replacement for 410-A, requiring no more than a possible TXV replacement to account for the change in operating pressures and refrigerant mass flow rate.

The results show that the equipment operating with R-452B refrigerant achieved similar capacity to the equipment operating with R-410A, but used less total power in each test performed. The combination of providing comparable cooling capacity using less power is what results in the better efficiency observed for the unit operating with R-452B. R-452B showed a 5% improvement in the equipment coefficient of performance at the AHRI rated condition (95°F) and 4% improvement in coefficient of performance on average across all tested conditions.

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