A method of operating an HVAC system using a controller includes predicting a first predicted temperature of an enclosed space during an unoccupied time with the HVAC system off. The controller determines if the first predicted temperature is less than a set-point temperature. Responsive to a determination that the first predicted temperature is less than the set-point temperature, the controller predicts a second predicted temperature of the enclosed space if the HVAC system is operated for a first runtime. The controller determines if the second predicted temperature is less than the set-point temperature and, responsive to a determination that the second predicted temperature is not less than the set-point temperature, the controller operates the HVAC system for the first runtime.

An air conditioner unit includes a refrigeration loop, a variable speed compressor coupled to the refrigeration loop, an indoor temperature sensor, an electric heater, and a controller operably coupled to the variable speed compressor, the indoor temperature sensor, and the electric heater. The controller is configured to operate the variable speed compressor at a target speed, identify an auxiliary heating trigger of the air conditioner unit, and operate the electric heater according to the auxiliary heating trigger.

Embodiments of the present disclosure are directed to a furnace that includes a blower configured to operate to force a fluid through the furnace, a motor having a rated speed, in which the motor is coupled to and configured to actuate the blower, and a controller configured to receive data indicative of an operating characteristic of the furnace and regulate operation of the motor to be at or below an operational speed limit. The controller is configured to set the operational speed limit based on the data indicative of the operating characteristic of the furnace, such that the operational speed limit is less than or equal to the rated speed of the motor.

The invention relates to method (600) for operating an HVAC system, the method comprising: obtaining (602) a plurality of directly measured parameters from one or more data sources; determining (604) one or more indirectly measured parameter based on one or more of the plurality of directly measured parameters; and monitoring (606) energy flow of the HVAC system, based on the plurality of directly measured parameters and the one or more indirectly measured parameters, wherein the energy flow corresponds to heat transfer between the heat transfer medium and the air. The invention further relates to a an apparatus for operating an HVAC system which comprises means of monitoring an energy flow, based on a plurality of directly measured parameters and one or more indirectly measured parameters.

An air conditioner unit includes a refrigeration loop, a variable speed compressor coupled to the refrigeration loop, an indoor temperature sensor, an electric heater, and a controller operably coupled to the variable speed compressor, the indoor temperature sensor, and the electric heater. The controller is configured to operate the variable speed compressor at a target speed, identify an auxiliary heating trigger of the air conditioner unit, and operate the electric heater according to the auxiliary heating trigger.

A heat pump system adjusts a degree of subcooling of an indoor-side heat exchanger in a heating priority mode, and adjusts any one of a degree of subcooling of a hot-water supply-side heat exchanger (water-side heat exchanger) and a discharge temperature of a compressor in a hot-water supply priority mode.

A combination air and ground source heating and/or cooling system. The system includes an indoor unit, an outdoor unit and an in-ground unit, each of which has a coil, an inlet line and an outlet line. The system also comprises a flow connector, a coupling and a controller. The controller is configured to control the flow connector and coupling so that the system is selectively operable in three different modes. In the first mode, refrigerant bypasses the coil of the outdoor unit, while, in the second mode, refrigerant bypasses the coil of the in-ground unit. In the third mode, refrigerant flows through the coils of the in-ground and outdoor units.

The invention relates to an HVAC apparatus, method, and system. Aspects of the invention include a supplemental heat source with an air handler unit for a conventional forced air heating and cooling system. The supplemental heat source in one example is a hydronic subsystem. It can be used alone or to supplement the forced air subsystem. Another aspect of the invention includes an air handling subsystem that has a housing that can be highly flexible in configuration and installation. The housing can support internal components, including a hydronic or other supplemental heat source with the forced air components. At least two sides of the housing can be configured for access for maintenance and repair. A control system can be designed to eliminate need for defrost cycle for forced air refrigeration-type subsystem and/or for better maintenance for comfort in the air conditioned space.

A system and method that optimizes energy consumption in an HVAC unit by minimizing chiller activity. The system uses a control unit that overrides a thermostat in at least one room to close a cooling valve that leads a fluid input to the room. When multiple cooling valves are closed through the rooms, the consequential return fluid maintains greater cooling capacity and thus, the chiller does not have to operate at full capacity. The control unit individually controls components in the HVAC unit, which were previously controlled by switches on the thermostat. The control unit includes a temperature sensor that monitors an environment, such as the room and a plenum. The control unit also includes a control relay that closes the cooling valve on the HVAC unit when the predetermined temperature of the control unit is above the thermostat temperature set by a room occupant.

A heat-pump circuit may include an indoor heat exchanger, an outdoor heat exchanger, a compressor adapted to circulate a working fluid between the indoor and outdoor heat exchangers, and an expansion device disposed between the indoor and outdoor heat exchangers. A monitor for the heat-pump system may include a return-air temperature sensor, a supply-air temperature sensor, and a processor. The return-air temperature sensor may be adapted to measure a first air temperature of air upstream of the indoor heat exchanger. The supply-air temperature sensor may be adapted to measure a second air temperature of air downstream of the indoor heat exchanger. The processor may be in communication with the return-air temperature sensor and the supply-air temperature sensor. The processor may be programmed to determine a working-fluid-charge condition of the heat-pump system based on the first and second air temperatures.