Superheat and sub-cooling control of refrigeration system

Abstract

A refrigeration vapor compression system including a compressor, an electronic expansion valve with closed loop feedback into a controller, sensors to measure and monitor the system superheat and sub-cooling, and condenser fans controlling the flow of air through the condensing coils, the refrigeration system is operated in at least one of two functional modes to either give priority control to the level of superheat in the system or maintain a minimum level of sub-cooling in the system.

Description

CROSS REFERENCE TO RELATED PATENTS AND APPLICATIONS[0001]This application claims priority to and the benefit of the filing date of U.S. Provisional Patent Application Ser. No. 61 / 873,971, filed Sep. 5, 2013, which application is hereby incorporated by reference.BACKGROUND[0002]The present disclosure broadly pertains to the field of refrigerant vapor compression systems, and particularly to a system for dynamically optimizing capacity and efficiency during less than optimal operating conditions to provide enhanced performance.[0003]Superheat is typically defined as the amount of heat added to a refrigerant vapor after a change of state occurring in the evaporator of a refrigeration system. This measurement is an indicator of the performance of the evaporator portion of the system and can have a direct influence on overall system efficiency. It is known to calculate the system superheat using a variety of methods, i.e. using pressure / temperature sensors located between the outlet of t...

AI Technical Summary

Benefits of technology

The system can be used to cool a computer system. The controller can adjust the speed of a condenser fan and the output capacity of a compressor to keep the system temperature within a certain range. It can also adjust the expansion valve to keep the system pressure within a certain range. Overall, the system can help to keep the computer system running at an optimal temperature.

Problems solved by technology

In variable speed refrigeration systems where modulation of compressors, indoor blowers, condenser fans with active control of superheat and sub-cooling is possible with appropriate sensors and direct feedback control loops, conditions can develop where full optimization of each and every control parameter independent of and without regard to interaction between these control parameters may cause less than optimal performance of the system.

Reduced capacity and degraded efficiency may be observed in the varying conditions such systems will routinely encounter in the installed environment in which they are expected to operate.

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