Field investigations on frosting suppression for variable-capacity ASHPs through optimizing their operations and configurations

It has been known that for space heating ASHPs, different operations and configurations can influence their frosting suppression performances. However, the practical applications through varying the operations and configurations of ASHPs for frosting suppression has not been well documented. Therefore, in this paper, field investigations on frosting suppression for variable-capacity ASHPs through optimizing their operations and configurations are reported. The investigations were based on two multi-compressor ASHPs of the same size, one being conventional, and the other being optimized, with respect to their operations and configurations. The outdoor airflow rate and the surface area of outdoor coils of the optimized ASHP were twice as much as those of the conventional ASHP. By comparing the field measured results from the optimized ASHP with those from the conventional ASHP, it could be found that for the optimized ASHP, its frosting rate and frosting-defrosting loss efficiency could be reduced by 37.2% to 39.6%, and 31% to 34.2%, and its operating performances improved by 5% to 22%, respectively. Therefore, optimizing the operations and configurations of ASHPs would have significant potential for improving their frosting suppression performances, and consequently their actual operating performances under part-load conditions.