High performance refrigerator having dual evaporator

Abstract

A high performance refrigerator includes a cabinet with a unitary refrigerated interior and a refrigeration fluid circuit having first and second evaporators located within the cabinet and separated from the refrigerated interior by respective first and second evaporator covers. The refrigerator also includes a first damper controlling flow between the first evaporator and the refrigerated interior, and a second damper controlling flow between the second evaporator and the refrigerated interior. A controller directs the refrigerator to operate a three-way valve in the refrigeration fluid circuit so as to direct refrigerant to only one of the evaporators when the other requires defrosting. Both evaporators may be used to remove heat from the unitary refrigerated interior during an initial cooling or immediately after the cabinet is opened.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]The present application claims the priority benefit of U.S. Provisional Patent Application No. 61 / 548,800 (pending), filed Oct. 19, 2011, the disclosure of which is hereby incorporated by reference in its entirety herein.FIELD OF THE INVENTION[0002]The present invention relates generally to refrigerators or freezers and, more particularly, to refrigeration systems for use with high performance blood bank refrigerators or plasma freezers.BACKGROUND OF THE INVENTION[0003]Refrigeration systems are known for use with laboratory refrigerators and freezers of the type known as “high performance refrigerators,” which are used to cool their interior storage spaces to relative low temperatures such as about −30° C. or lower, for example. These high performance refrigerators are used to store blood and / or plasma, in one example.[0004]Known refrigeration systems of this type include a single loop circulating a refrigerant. The system transfers energy...

AI Technical Summary

Benefits of technology

This patent describes a refrigerator with two evaporators and a three-way valve that can direct refrigerant to either evaporator for defrosting. The method involves stopping operation of one evaporator, defrosting the other evaporator, and starting operation of the defrost heater. The technical effect of this invention is to improve the efficiency and performance of refrigerators by allowing for selective defrosting of evaporators based on their need, while maintaining a consistent temperature across the refrigerated interior.

Problems solved by technology

One common problem with known refrigeration systems is that the evaporator includes coils that tend to produce and accumulate frost along the outer surface if any moisture is ambient within the cooled space.

If enough frost accumulation occurs, the ability of the evaporator to remove heat from the cooled space is detrimentally impacted.

This defrost cycle may be a manual defrost or an automatic defrost, but both types of defrost cycles are undesirable for various reasons.

This cycle is undesirable because the products stored in the cabinet need to be stored in an alternative refrigerator for the duration of the defrost cycle, and also because the melting process can produce a significant amount of moisture that needs to be removed from the cabinet.

The cooled space necessarily undergoes a temperature spike during this automatic defrost cycle, which can jeopardize the products stored in the cabinet.

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