Systems and methods for temperature control

A temperature control system for alternative control of the temperature of a process tool by chilling or heating using a cycling thermal transfer fluid comprising:

• a refrigeration loop for flowing a refrigerant and including a compressor, a condenser in series therewith, a refrigerant flow control, and an evaporator/heat exchanger;
• a thermal transfer fluid loop comprising a fluid reservoir, a pump, and connections for cycling the fluid to and from the process tool, the fluid loop being directed through the evaporator/heat exchanger;
• a bypass path for pressurized hot gas refrigerant from the compressor to the evaporator/heat exchanger;
• and
• a hot gas bypass valve responsive to the input pressure of refrigerant to the compressor for directing hot gas into the bypass path, such that compressor energy is used for cooling when the flow control is used and heating when the flow control shuts off refrigerant flow.

The method of controlling the temperature of a process tool with a thermal transfer fluid supplied from a reservoir, comprising the steps of:

• pressurizing a refrigerant to provide pressurized hot gas;
• when the process tool is to be heated, extracting pressurized hot gas for heating the thermal transfer fluid from the reservoir while first preheating the fluid in the reservoir by passing the hot gas through the reservoir;
• when the process tool is to be cooled, condensing the pressurized hot gas to a liquid pressurized refrigerant, and
• controllably alternatively directing the hot gas or the liquid pressurized refrigerant in heat exchange relation to the thermal transfer fluid to heat or chill the thermal transfer fluid to a selected temperature level before application to the process tool.

A method for controlling the operating temperature of a process tool in a range from about −40° C. to about +120° C. using a fluid reservoir for thermal transfer fluid moving in a loop through the process tool and a refrigeration loop including a compressor, condenser, evaporator/heat exchanger and a controllable expansion valve for controlling the flow of pressurized liquid refrigerant to the evaporator/heat exchanger, comprising the steps of:

• generating an indication of the difference between the desired and actual temperature thermal transfer fluid to be supplied to for the process tool;
• passing the thermal transfer fluid through the evaporator/heat exchanger;
• controlling, by use of the expansion valve, the rate of evaporation of the condensed refrigerant in the evaporator/heat exchanger based upon the difference indication when the desired temperature is in a low temperature zone;
• extracting a hot gaseous refrigerant flow from the compressor for use in heating the thermal transfer fluid when the desired temperature is in a median temperature zone;
• passing the hot gaseous refrigerant through the reservoir contents in heat exchange relation with the thermal transfer fluid;
• adding heat to the heat transfer fluid to raise the temperature of the process tool to a high temperature zone, and
• flowing the thermal transfer fluid through the process tool to regulate the temperature of the process tool.