Temperature control system and method TDSF plus

摘要

Versatile temperature control systems adaptable to many different applications employ different states and proportions of a pressurized dual phase medium in direct contact with a thermal load. In one aspect of the invention, thermal energy generated by pressurization of a gaseous medium is stored at a selected temperature level so that it is later readily accessible. In addition, in accordance with the invention temperature control of a two-phase medium can be exercised across selectable dynamic ranges and with different resolutions. In accordance with such features, the control can be exerted by varying the input flow rate of a mixture applied to a thermal load, or by controlling the back pressure of the flow through the thermal load.;In accordance with another feature of the invention, substantial energy conservation can be effected by employing an ambient temperature evaporator configuration between the thermal load and the input to the compressor. This variant also utilizes the two-phase characteristics of the medium. Moreover, the system can be configured compactly utilizing a thermal reservoir for retaining thermal energy for special purposes. In a food processing system for providing a frozen product, for example, the thermal reservoir can be accessed to utilize the refrigerant itself in different operating modes, such as rapid heating and system cleansing. In the food processing application, target temperatures can be set and maintained on a platen which is to receive food ingredients using energy flows at two different enthalpies, to enable rapid freezing or temperature elevation.

主权项

1. A control system employing a two-phase refrigerant output from a compressor to control the temperature of a thermal load in different modes so as to provide different selectable dynamic ranges and degrees of temperature resolution, the system comprising:
a first control loop receiving the compressor output and providing a variable temperature level output to the thermal load, the first control loop including flow circuits for mixing a variable proportion of the compressed output of the compressor with a cooled expanded derivative flow of the remainder of the compressed output to control the temperature of the thermal load; a second control loop receiving the output of the thermal load and including an additional flow circuit for alternatively controlling the temperature of the thermal load by regulating the back pressure presented by the thermal load; a controller responsive to mode commands for providing control signals to activate the first and second control loops and establish target temperatures therefore; and a third control loop responsive to the controller and coupled in the output of the thermal load, the third control loop including a thermo-expansion valve and a series-coupled ambient temperature evaporator in circuit therewith and providing an ambient temperature level flow to the compressor input, wherein the thermo-expansion valve is responsive to the temperature at the compressor input.