Closed loop air conditioning system including pressurization by blockage and aspiration

摘要

An air conditioning system for an enclosed space including a jointly driven compressor and expander of the positive displacement type each having an inlet port and an outlet port with a primary heat exchanger connected between the compressor outlet port and expander inlet port and a secondary heat exchanger connected between the expander outlet port and the compressor inlet port to complete a closed loop having a charge of air and with one of the heat exchangers being thermally coupled to the enclosed space. Ambient air is injected into the closed loop to raise the pressure in the secondary heat exchanger to substantially above the atmospheric level to increase the heat rate of the system. Alternatively air is bled from the loop to reduce the pressure in the secondary heat exchanger thereby to decrease the heat rate of the system. In one embodiment of the invention a blocking valve in the path of the air stream flowing through the secondary heat exchanger is momentarily closed to create a vacuum at the compressor inlet port and an injector valve at the compressor inlet port is coincidentally opened so that ambient air is injected by the process of aspiration. While the system may be manually controlled, it is one of the features of the invention that injection and bleeding are under the automatic and corrective control of a temperature pressure sensing device so that the heat rate of the system is varied automatically in accordance with the requirements of an enclosed space for automatic maintenance of a present condition. The system is usable in a refrigerating mode, making use of the absorption of heat in the secondary heat exchanger or in the heat pump mode utilizing the dissipation of heat in the primary heat exchanger, with automatic control of space temperature in both of the modes.