Abstract:
A heat pump system includes a refrigerant circuit. First and second heat exchangers are arranged in the refrigerant circuit. A flow reversing device selectively changes a direction of flow in the refrigerant circuit between the first and second heat exchangers. A centrifugal compressor is arranged in the fluid circuit and has first and second impellers arranged in series relative to one another to provide a desired compressor pressure ratio. In one example, the centrifugal compressor mounts the first and second impellers on opposing ends of a shaft. The first and second impellers respectively include first and second stage inlets and outlets. One example desired compressor pressure ratio of at least 10:1 corresponds to a second stage outlet pressure to a first stage inlet pressure. A first diffuser is arranged at the first stage outlet, and the first diffuser is a variable geometry diffuser.
Abstract:
A refrigeration system includes a chiller having a refrigerant loop. A compressor is part of and in fluid communication with the refrigerant loop. The compressor has two stages, one with a variable geometry diffuser and one with a fixed geometry diffuser.
Abstract:
A process for controlling operation of a heating, ventilation and air conditioning system broadly comprises providing a heating, ventilation and air conditioning system having an evaporator, a condenser, a compressor having an inlet and an outlet, and at least one flow control device; measuring a performance parameter of the heating, ventilation and air conditioning system; determining a performance parameter measurement of the flow indicative of onset of surge; determining a surge line of the heating, ventilation and air conditioning system based upon the performance parameter measurement; and independently controlling the at least one flow control device based upon the performance parameter to mitigate an onset of the surge.