Comparative Analysis of Two Types of Positive Displacement Compressors for Air Conditioning Applications

Different types of positive displacement compressors are employed in low-capacity air conditioning applications. Understanding the advantages and drawbacks of each of these technologies is important in order to identify the ranges of cooling capacities at which a specific compression technology is more efficient. This paper presents a comparative analysis between two positive displacement compressors (rolling piston and scroll) designed for air conditioning applications. The compressors operate with R-22 and present a nominal cooling capacity of 18000 BTU/h at the AHRI-A checkpoint condition. First, the compressors were tested in a hot-cycle test bench to measure the mass flow rate and power consumption for MBP and HBP operating conditions. The results showed that the most efficient compressor depends on the operating condition. Â After this, simulation models for each compressor were validated against the experimental data, showing good agreement. Therefore, through the simulation models, it was possible to evaluate the effect of different aspects, such as leakage, heat transfer and discharge process, on the efficiency of each compressor