Compact refrigeration system

Abstract

A selectively controllable valve is arranged in a refrigeration circuit which interconnects the evaporator and the condenser and is controlled so that a pressure differential is built up across the valve. The valve is selectively opened to allow 'batches' of working fluid to pass therethrough. In some embodiments, the working fluid which is allowed to pass through the valve, is heated in a chamber to increase the amount of pressure on the downstream side of the valve. This produces expanded pressurized working fluid which increases the pressure in the condenser and forces previously condensed and liquefied working fluid through a flow restricting transfer device into an evaporator. Condensation of the just heated gas in the condenser subsequently reduces the pressure on the downstream side of the valve and establishes conditions suitable for the passage of a further amount of gaseous working fluid while itself becoming liquid to be forced through the flow restricting transfer device. Quick repetition of these cycles establishes a dynamic flow conditions and maintains the flow of liquefied working fluid into the evaporator. In other embodiments, the pressure differential is produced and/or augmented by pump such as a piston pump, or a combination of the pump and the heating chamber. If sufficient condensation can be induced using the operation of the condenser or by some other means and the required pressure differential developed, then both the heater and the pump can, depending on the circumstances and the cooling capacity that is required, be omitted. The flow of liquid working fluid from the condenser is transferred to the evaporator via either a capillary tube or a selectively controllable valve arrangement which can also posses pumping characteristics if so desired.