Energy-optimized cycle control of time-variant loads for thermal management of vapor compression systems

A method for controlling a multiple-load vapor compression system, wherein the multiple-load vapor compression system comprises:

• a refrigeration loop configured to transfer heat from multiple load locations to at least one rejection location, each load location having a load temperature resulting from a heat load at the load location, the heat load at a particular load location defining an evaporator load for the particular load location, the refrigeration loop having a plurality of components in fluidic communication through refrigeration lines containing a refrigerant, the plurality of components comprising:
• an adjustable-capacity compressor that compresses refrigerant vapor from a low-pressure side of the refrigeration loop and delivers compressed refrigerant vapor to a high-pressure side of the refrigeration loop;
• a condenser that condenses at least a portion of the refrigerant from the adjustable-capacity compressor to produce chilled refrigerant, the condenser being in thermal communication with the rejection location via a rejection apparatus having an adjustable rejection capacity;
• an expansion valve associated with each load location, each expansion valve having an adjustable opening through which the chilled refrigerant from the condenser expands and is delivered back to the low-pressure side;
• an evaporator at each load location that transfers heat from the load location of the evaporator to the refrigerant arriving at the evaporator from the expansion valve associated with the load location and delivers the refrigerant back to the adjustable-capacity compressor;
• a first sensor that measures a low-side pressure of the low-pressure side of the refrigeration loop;
• a second sensor that measures a high-side pressure of the high-pressure side of the refrigeration loop;
• multiple third sensors, each third sensor being associated with an individual evaporator and measuring the load temperature at the load location of the individual evaporator;
• a control apparatus coupled to the adjustable-capacity compressor, each expansion valve, the first sensor, the second sensor, each of the third sensors, and the rejection apparatus,
• the method comprising:
• selecting desired set-point temperature ranges for the load temperatures at each individual load location of the multiple load locations;
• and
• operating the multiple-load vapor compression system to transfer heat from the multiple load locations to at the least one rejection location;
• adjusting continually with the control apparatus while the multiple-load vapor compression system is operating one or more of:
• a capacity of the adjustable-capacity compressor so as to maintain a maximum low-side pressure, as measured by the first sensor, with respect to the evaporator load at an individual load location having a coldest desired set-point temperature range of the multiple load locations;
• and
• the adjustable rejection capacity of the rejection apparatus so as to maintain a minimum high-side pressure as measured by the second sensor;
• and
• each adjustable opening of each expansion valve independently from other expansion valves in the multi-load vapor compression system, so as to maintain the load temperatures measured by the third sensors associated with each evaporator within the desired set-point temperature range for each load temperature.