Experimental Investigation on Off-Design Characteristics of R290 Rolling Piston Compressor

The test platform of R290 rolling piston compressor is established to study the variation of performance parameters under different conditions, including volumetric efficiency (eta(V)), coefficient of performance (COP), cooling capacity (Q), electric power (W), exhaust temperature (t(d)), electrical efficiency (eta(el)), comprehensive efficiency coefficient (eta(com)). With the increase in suction temperature (t(s)), COP increases by 8.3% partly due to the increase in t(d); eta(V) increases slowly in the range of 0.86-0.87 (mainly affected by temperature coefficient); eta(el) and eta(com) increase by 3.2% and 5.6%, respectively. At variable compression ratio (pi) conditions, with the decrease of P-e (VPe), COP decreases by over 25%, while with the increase of P-c (VPc), COP decreases by over 38%, which attributes to the different decline rates of W (decreasing slightly at VPe and increasing by over 30% at VPc); eta(V) decreases slowly (mainly affected by volume coefficient and temperature coefficient); eta(el) decreases with the increase of pi; the decline rate of eta(com) at VPc is 2-3 times that at VPe, which indicates that the frequent fluctuation of P-c will lead to the significant decrease of eta(com). This research provides experimental basis for the design and further improvement of R290 rolling piston compressor.