A trade study on motor types for large hvac systems with integrated motor-compressors

Typically, HVAC systems consume a significant amount of energy in both commercial and domestic buildings. The major part of energy consumed in an HVAC system is consumed by the compressor motor, which operates at high shaft speeds in direct drive systems. The efficiency of the motor and cost effectiveness of the motor drive system are two major factors determining the motor type to be used in HVAC chiller applications. The cost of the motor and electrical drive is a factor decided by motor material cost, manufacturing complexity, power factor and drive switching frequency. Since the HVAC chillers are not continuously run at rated power, the integrated part load value (IPLV)is considered here instead of rated efficiency. This paper presents different trade-offs of using the permanent magnet synchronous motor (PMSM), induction motor (IM), switched reluctance motor (SRM), and PM assisted synchronous reluctance motor (SynRM)for designing a 60 Nm, 16500 rpm compressor motor to run in a hermetic refrigerant environment.