Thermal control system and method

A method of controlling the temperature of process equipment with internally flowing fluid comprising the steps of:

• selecting a fluid whose transition temperatures for liquefaction and evaporation are suitable for the desired temperature operating range of the process equipment;
• pressurizing the fluid to a high temperature, high pressure gas;
• cooling a first flow of the pressurized gas to provide a saturated fluid;
• transferring a variable second flow of pressurized gas to a mixing zone;
• controllably expanding the first flow state to a liquid/vapor state before the mixing zone;
• selectively mixing the selected proportion of high temperature gas with the liquid/vapor flow to provide a saturated fluid mixture at a controlled temperature level;
• transferring the saturated fluid mixture through the process equipment to effect direct heat exchange;
• adjusting the pressure of the saturated fluid mixture to vary the temperature of the process equipment, and
• recycling the fluid for repressurizing and repeating the cycle.

The method of controlling the temperature of a process tool with a fluid comprising the steps of:

• compressing a refrigerant having a liquid/vapor state dependent on pressure and temperature to a high pressure gaseous state in the range of about 120° C. and about 400 psi;
• condensing a portion of the flow in the gaseous state to a high pressure, liquid state at approximately ambient temperature;
• expanding a part of the condensed refrigerant flow to a liquid/vapor mix at a selected temperature;
• mixing a selected proportion of the high pressure gaseous flow with the expanded flow to achieve a selected nominal temperature and pressure in the mix;
• passing the refrigerant flow directly in heat exchange relation with the process tool;
• adjusting the temperature of the process tool by adjusting the proportion of the high temperature gaseous flow while maintaining a liquid/vapor mix, and
• conditioning the temperature and pressure of the refrigerant in selected ranges to return a gaseous refrigerant suitable for recycling and recompression.

The method of exchanging thermal energy between a vaporizable fluid and a process unit of variable thermal load whose temperature is to be controlled, comprising the steps of:

• converting the fluid to a pressurized high temperature gaseous state;
• condensing a first portion of the pressurized gas to a liquid at the pressure at a predetermined pressure;
• diverting the remainder of the pressurized gas at approximately the predetermined pressure into a separate path;
• expanding the pressurized liquid to a saturated fluid of a selected pressure to arrive at a first pressure and enthalpy level;
• extracting a selected proportion of the pressurized gas to provide an adjusted pressure and enthalpy level;
• mixing the expanded saturated fluid and the extracted portion of the gas to provide a fluid of target pressure and enthalpy;
• passing the mixed fluid of target pressure and enthalpy through the process unit in thermal exchange relation to be condensed or evaporated depending on the thermal load thereat;
• adjusting the process unit temperature level to a new level by adjusting the pressure of the mixed fluid;
• transporting the mixed fluid for recycling while restoring the pressure and temperature to within predetermined limits, and
• reconverting the mixed fluid to a pressurized high temperature state.

A method of using a refrigerant as a direct heat exchange medium for controlling the temperature of a controlled unit with which it is in thermal contact comprising the steps of:

• compressing the refrigerant to a high temperature high pressure vapor state;
• condensing a first flow of the compressed refrigerant to a liquid;
• forming a first flow of misted vapor form from the condensed liquid;
• combining a selected proportion of a second flow, of the high temperature and high pressure vapor with the first flow to form a controlled pressure mixture, and
• directing the combined flow in thermal exchange relation with the controlled unit.