Patent ID: 8240160

Claim:
A method of controlling temperature changes so as to minimize overshoot in the temperature of a thermal load in a process which uses a flow of compressed two-phase refrigerant divided variably into a mixture of pressurized hot gas of variable mass flow rate and a differential flow of expanded liquid/vapor mix, comprising the steps of: determining a positive or negative differential between a new target temperature set point for the thermal load and an existing temperature set point at which the thermal load is being maintained; accessing stored control algorithms to compute the rate of change to a new mass flow rate for the hot gas to be combined with the differential flow of expanded liquid/vapor mix so as to attain the desired revised temperature level for the thermal load; incrementally varying the flow rate of the hot gas at a controlled transition rate dependent on the total span of change in temperature and in the positive or negative direction for the new mass flow rate needed to reach the target temperature, and maintaining the transition flow rate change in a range such that there is minimal overshoot in temperature of the thermal load when the desired target temperature is reached.