Compressor capacity modulation scheme

The need for refrigeration system capacity control arises from the fact that system capacity must match the load under a variety of operating conditions. For instance, if the refrigeration load decreases, the inherent system response is to decrease the evaporating temperature and pressure. This change in the evaporator's operating conditions results in reduced compressor capacity, which ultimately matches the reduced refrigeration load. The paper discusses various capacity control methods and evaluates them in the light of current technology.