Climate control system

Described is a climate control system with an air conditioning or a heat pump and a method to provide desirable temperature and humidity of indoor air. In addition to a compressor, a condenser, an evaporator, and an expansion device, the air conditioner/heat pump includes an auxiliary coil, valve means, refrigerant communication means, and control means. In hot climate the system operates in two separate modes: a conventional cooling mode and a cooling mode with enhanced dehumidification. In the conventional cooling mode the valve means direct refrigerant leaving the condenser to the expansion device and then to the auxiliary coil to absorb heat from conditioning air by refrigerant in the auxiliary coil. In this mode an extra amount of liquid refrigerant is stored in the refrigerant communication means. In the mode with enhanced dehumidification the valve means direct refrigerant leaving the condenser to the auxiliary coil to reject heat to cooled and dehumidified in the evaporator air from refrigerant in the auxiliary coil. Refrigerant in the dehumidification mode is subcooled, evaporating temperature is lower and cooling capacity of the evaporator is higher than is the conventional cooling mode. These factors increase moisture condensation on the evaporator surface. On the other hand, the temperature of conditioning air is higher than in the conventional cycle due to the heat absorbed by air from the auxiliary coil. Control means that include a thermostat and a humidistat alternate a position of the valve means to provide requested temperature and humidity of indoor air. In cold climate the system may have heating means and a humidification device. Same as in the cooling operation the thermostat and the humidistat manage operations of the heating means and the humidification device.