Heat Pump Cycle Using Refrigerant Mixtures of HFC32 and HFO1234yf

Abstract

Countermeasures for global warming have been promoted internationally. Heat pump cycles that utilize refrigerants with high global warming potential values are required to adopt the next generation refrigerants to conform to the revised Montreal Protocol. Refrigerants R410A is commonly used in the room air conditioners while it has been substituted with HFC32 in Japan; yet their global warming potential values are relatively high and are going to be phased down in the near future. On the other hand, refrigerant mixtures such as the blend of HFC32 and HFO1234yf with extremely low global warming potential can be considered as possible alternatives in compromising the flammability and the ecological tribulations. Targeting the global warming potential value of 150 or lower, the performance of HFC32/HFO1234yf (22/78 mass%) blend was evaluated using drop-in tests, and the results were compared with those of R410A and HFC32. Optimum charge amounts for these refrigerants were first evaluated, followed by the performance comparison in terms of the coefficient of performance from part- to full-load operations. The results showed that the current blend with the low global warming potential less than 150 is comparable to the targeted substitutes at part-load operations while within 83 – 87% of the COP using HFC32 was achievable at the full-load. The performance results from these experiments could serve as the basis for the refrigerant evaluation targeting the global warming potential 150.

Acknowledgements

This work was funded by the “Development of Assessment Techniques for Next-Generation Refrigerant with Low GWP Values” from the New Energy and Industrial Technology Development Organization (NEDO), Japan.

Additional information

Notes on contributors

Kosei Takezato

Kosei Takezato obtained his Master Degree from the Department of Advanced Environmental Science and Engineering, Faculty of Engineering Sciences, Kyushu University. His research interest includes heat pump technologies, performance testing of low GWP refrigerants.

Shou Senba

Shou Senba is currently enrolled as a Master student in the Graduate School of Science and Engineering of Kyushu University. He obtained his Bachelor Degree from the Department of Energy Science, Faculty of Engineering, Kyushu University. Currently, he is engaged in research on the heat pump cycle using low GWP mixed refrigerant.

Takahiko Miyazaki

Takahiko Miyazaki is a Professor in Department of Advanced Environmental Science and Engineering, Faculty of Engineering Sciences, Kyushu University. He holds a BSc in Mechanical Engineering from Chuo University, Japan and MSc in Renewable Energy and Architecture from the University of Nottingham, UK, and PhD in Engineering from Tokyo Agriculture and Technology (TUAT), Japan. He worked as an Assistant Professor at Faculty of Engineering, TUAT before he joined Kyushu university as an associate professor at Kyushu University in 2011. He promoted to a full professor at Kyushu University in 2017. His specific research interests are in energy savings by utilization of low grade thermal energy. He involved in several research projects, and currently working on “Research and development of waste heat driven cooling heat pump for automobiles” in Thermal Management Materials and Technology Research Association (TherMAT). He has published more than 150 articles in peer-reviewed journals and international conference proceedings. He supervised a Japanese book on “Low Temperature Waste Heat Utilization Technologies by Adsorption Refrigerators/Heat pumps”.

Nobuo Takata

Nobuo Takata received his Doctoral degree from the Institute for Functional Materials Science from Kyushu University. He has an extensive industrial experience while working at Fuji X-Ray and as an Engineer at the Institute of Industrial Science, Kyushu University. He is currently working as a technical specialist at Kyushu University Graduate School of Science and Engineering. His research work extends from the detection of spontaneous combustion and gas protrusion in coal mines, to the condensation phenomena of CFCs, to research on immersion boiling and cooling of chips with micro-pin fins. At present, he is working on the vapor compression heat pump cycles utilizing refrigerant mixtures with CO2 as well as low GWP alternatives.

Yukihiro Higashi

Yukihiro Higashi is a Professor at the Research Center for Next Generation Refrigerant Properties (NEXT-RP), International Institute for Carbon-Neutral Energy Research(I2CNER), Kyushu University, Japan. He received his Ph.D. from Keio University, Yokohama, Japan in 1986. Since 1987, he got the position of Assistant Professor at Iwaki Meisei University, Fukushima, Japan. In 2000, he became a Professor at the Iwaki Meisei University and he has been in his current position at Kyushu University since 2016. In 1998, he was a guest researcher of Thermophysical Properties Division, National Institute of Standards and Technology(NIST), Boulder, Colorado, USA. His career in research is focused on thermophysical property measurements of refrigerants and their mixtures, especially the measurement of critical point, PvT properties, vapor-liquid equilibrium and surface tension. He had been awarded Sadi Carnot Awards by the International Institute of Refrigeration (IIR), Asian Academic Award by JSRAE(Japan), CAR(China), SAREK(Korea) and Best Paper Awards 2009/2010 and 2014/2015 by International Journal of Refrigeration (Elsevier). He has been the member of countless refrigeration and mechanical engineering organizations such as JSRAE, JSME, JSTP and HTSJ. He is currently focusing on research regarding thermophysical property measurements of low Global Warming Potentials (GWPs) refrigerants.

Kyaw Thu

Kyaw Thu is an Associate Professor in the Department of Advanced Environmental Science and Engineering, Faculty of Engineering Sciences, Kyushu University. He completed his Ph.D. degree at the National University of Singapore (NUS) in 2010. His research interest includes heat and mass transfer in processes, adsorption science and technology, HVAC&R systems, thermophysical properties of refrigerants and numerical techniques for process simulation. Currently, he is serving as an Executive Editor of the Evergreen - Joint Journal of Novel Carbon Resource Sciences & Green Asia Strategy. He has published more than 100 peer-reviewed international journal papers and several conference papers. One of his papers has been recognized as one of the most cited articles in the International Journal of Refrigeration (IJR) since 2012.