Abstract: This invention provides a Refrigerant Side Economizer cycle and a fuel-heat based heating cycle for air conditioners, heat pumps, and chillers. The built-in refrigerant side economizer cycle can be substituted for an air-side economizer cycle or a water-side economizer cycle. It can provide an economizer cycle for split system air conditioners, chillers, coolers, and heat pumps. Also, it makes possible an economizer mode for variable refrigerant flow units. With this invention, the units can distribute heating from a fuel-heat source without compressor operation. During refrigerant side economizer mode, the refrigerant pump in the units maintains circulation without compressor operation, with a fraction of energy consumption. To allow for longer distance between split-system units, the refrigerant pump if needed can operate during compressor operation.

Abstract: The primary object of the present invention is to provide a basis for the design and implementation of a heating and cooling system (air conditioning system) which will reduce energy consumption over the presently used systems, reduce equipment and installation cost, and reduce maintenance cost. The use of this invention can mostly be used (but not only) in any commercial or residential building requiring heating and cooling. This system allows heating and cooling with water-cooled, self-contained air conditioning units or heat pumps, served by 2-pipe or single pipe, viable without heat pump operation, and can utilize waterside economizer. The system eliminates the need of having separate condenser water and separate hot water piping connections to the self-contained terminal air conditioning units.