Compressor VSD Control
Many refrigeration systems are designed for a peak load that rarely occurs, for example to provide sufficient capacity when the outside air temperature reaches 35 deg c, a fairly rare occurence in the UK. This means that for the majority of time the system is running at part load.
Many screw compressors are inefficient when operated at part load due to their slide valve capacity control. The efficiency of a screw compressor at 50% load can be 30% lower than when operating at full capacity.
This inefficient slide valve can be replaced with inverter (variable speed) control of the compressor motor, capacity is then accurately modulated by increasing or reducing motor speed. Maintaining optimum efficiency at all times, to reduce electrical consumption, costs and carbon emmissions.