Energy efficient air conditioning system utilizing a variable speed compressor and integrally-related expansion valves

An improved method for maintaining a confined space at a desired set point selected from temperature, humidity, or both, by conditioning the air in said space with an air-conditioning system of the type having a refrigerant which sequentially flows through compressor means which compresses vaporous refrigerant supplied by evaporator means, condenser means which is in heat exchange relationship with outdoor air for condensing refrigerant circulated from said compressor means, expansion means which expands liquid refrigerant from said condenser means, and evaporator means which is in contact selected from direct or indirect heat exchange relationship with air in a confined space for maintaining said confined space air at said desired set point, said evaporator supplying said refrigerant to said compressor means, the improvement for maintaining said set point of the confined space at variable heat loads therein and at variable outdoor air temperature without cycling said compressor means, which comprises:

• sensing a condition selected from the temperature, the humidity, or both of said confined space;
• varying the mass flow of said refrigerant with variable speed compressor means driven by a rectifier-inverter and responsive to said sensed confined space condition for maintaining said set point;
• and
• maintaining an adequate refrigerant mass flow to the evaporator means and an adequate pressure drop across said expansion means when said refrigerant mass flow varies for maintaining constant the desired set point of the confined space at varying outdoor air temperature, said expansion means comprising pressure regulator valve means connected by said refrigerant expansion means which, in turn, is connected to said evaporator means by a refrigerant line, the external equalizing line of said pressure regulator valve means being connected to the refrigerant line between said valve means.