The awarded invention is a new system to throttle the refrigerant between condenser and evaporator. This system enables the evaporator to be completely filled with boiling refrigerant. This is not usual in small- and medium-sized equipment, where the thermostatic expansion valve is common practice. With the related dry expansion, the final part of the evaporator serves to superheat the generated vapor and this process shows a relatively low heat transfer. The new expansion device aims to be an alternative for small-sized units with the advantage of a better heat transfer in the evaporator, working in a flooded instead of a dry mode. It incorporates an ejector for fluid recirculation, and several arrangements to protect the compressor and to control the condenser liquid contents.
The various aspects are brought together in an integrated unit, which does not depend on electronics. The basic control principle is to ensure that no liquid stores in the condenser; a slip flow of non-condensed gas serves as a signal, which is transferred to the throttle valve. It is expected that the new device in an appropriate system design brings an energy savings between 10 and 20 percent.
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Publication date: 11/13/2006