DEVELOPMENT OF A REVERSIBLE CO2 RESIDENTIAL AIR CONDITIONING SYSTEM
SINTEF Energy Research and The Norwegian University of Science and Technology (NTNU) in Norway have since 1997 analysed and developed reversible residential air conditioners and heat pumps (RAC split-type units) using carbon dioxide (CO2) as the working fluid. A CO2 prototype RAC split-type unit has recently been constructed and extensively tested in heating and cooling mode. The test results have been used for calculating the seasonal heating and cooling performance for two different climates; Greece (Athens) and Norway (Oslo). The results are compared with manufacturer data for two state of the art reference R-410A Japanese/European type mini-split units. Rating point performances for these two reference units were validated by experiments.The main results are shown in the table above. Based on the measurements, the calculated seasonal performance for the CO2 and the top liner R-410A unit in heating mode were more or less identical, as well as in cooling mode in the Oslo climate. However, in cooling mode in Athens climate, the seasonal performance of the CO2 unit was about 17％ lower than that of the top liner R410A unit.By comparing tests performed by Eurovent, reference unit 1 was found to have the highest rating point COP in both heating and cooling mode. Reference unit 2 had a 34 ％ lower rating point COP in cooling mode and a 45 ％ lower rating point COP in heating mode. The models are in the top and lower range in terms of efficiency for this split type systems.The CO2 compressor used in the prototype system was developed as a pilot unit. Efficiencies were measured to be lower (ηis～0.54) than what would be expected by a commercial product. Both heat pump and air condition results were recalculated with ηis=0.65, which is reported for R-410A compressors, and which should be realistic also for CO2 compressors. The increased efficiency causes the prototype system to be comparable to the top liner reference unit 1 on seasonal basis, both in cooling and heating mode for both the hot climate of Greece and the moderate climate of Oslo. By using an ejector, which is reported to give around 20％ improvement of the cooling COP at 35℃ ambient temperature, the seasonal performance of CO2 reversible systems will improve even more.
Jakobsen A. Skiple T. Neks(a) P. Wachenfeldt B. Skaugen G.
SINTEF Energy Research, Trondheim – Norway The Norwegian University of Science and Technology, NTNU
国际会议
The 22nd International Congress of Refrigeration(第22届国际制冷大会)
北京
英文
2007-08-21（万方平台首次上网日期，不代表论文的发表时间）