The disclosed technology includes a variable refrigerant flow (VRF) conditioning system including a single outdoor unit and a VRF path extending between the single outdoor unit and a plurality of terminals. The plurality of terminals can include a first terminal configured to condition air of an interior room and a second terminal configured to heat or cool a liquid. The VRF system can provide heating or cooling of air in different rooms or zones within a building or home while also providing heating or cooling of water. In response to a demand for heating or cooling at each terminal, the VRF system can vary the supply of refrigerant to each terminal, such that efficient and precise temperature regulation of air and liquid can be provided.

Air heating and potable water systems have a thermostat with a computer processing unit (CPU), a hot water heater, a hydronic air handler, and a primary pump controlling flow of hot water from the water heater into the hydronic air handler, which has a hydronic coil, a blower, and a first control panel having a CPU in operative communicates with the thermostat. The hydronic coil receives hot water from the water heater to warm air passing over the hydronic coil. The primary pump is in operative communication with the first control panel and an indicator of hot water flow. The indicator of hot water flow is in operative communication with either the thermostat or the first control panel, and any CPU in the system stores a priority instruction, which upon an indication of hot water flow deactivates or delays activation of the primary pump for a predetermined period of time.

The present invention improves the user-friendliness of a hot-water supply apparatus when using hot water supply and air conditioning. A switching control unit 27, which switches between heat medium flow paths 4 and 5 according to an air conditioning ready state or a hot-water supply ready state, switches a heat medium flow path to the hot-water supply ready state by a switching valve 21 in the case where air conditioning is not used by the time an air conditioning standby time elapses during standby in the air conditioning ready state.

The disclosed technology includes a variable refrigerant flow (VRF) conditioning system including a single outdoor unit and a VRF path extending between the single outdoor unit and a plurality of terminals. The plurality of terminals can include a first terminal configured to condition air of an interior room and a second terminal configured to heat or cool a liquid. The VRF system can provide heating or cooling of air in different rooms or zones within a building or home while also providing heating or cooling of water. In response to a demand for heating or cooling at each terminal, the VRF system can vary the supply of refrigerant to each terminal, such that efficient and precise temperature regulation of air and liquid can be provided.

A heat pump may include a compressor configured to compress a refrigerant, a first temperature sensor provided in heating pipes connected to a heating device that heats an indoor space to sense a temperature of fluid flowing through the heating pipes, and a controller. The controller may be configured to determine whether a boiler is operating to heat an indoor space or is operating to supply hot water based on a sensing value of the first temperature sensor. The compressor may operate when the controller determines that the boiler is not operating to heat the indoor space and/or determines that the boiler is operating to supply hot water.

The present invention is generally directed to a system for providing heating, cooling, and domestic hot water (DHW) using a water source heat pump, the system including: a compressor; a source heat exchanger; a load heat exchanger; a DHW heat exchanger; and a DHW storage tank. In some embodiments, the system may be concealable, and mounted between two wall studs. In some embodiments, a water-to-water water source heat pump and DHW storage tank may be mounted between the same wall studs, the system having a width of no more than 14.5″ and a depth of no more than 7″. In some embodiments, in a heating cycle high-temperature high-pressure refrigerant in a gaseous phase is provided to both a brazed plate DHW heat exchanger and a brazed plate load heat exchanger in a parallel manner so one of the heat exchangers receives the refrigerant at a time.

Embodiments include systems and methods for heating water and cooling air simultaneously, as well as other simultaneous heating and cooling operations. An example variable refrigerant flow conditioning system includes an outdoor unit having a compressor, a condenser coil, and a fan, a water heater coupled to the outdoor unit, a first air conditioning unit coupled to the outdoor unit, and a controller. The controller may be configured to determine that a cooling operation mode is active during a first time interval, cause vapor refrigerant to be directed from the outdoor unit to the water heater and liquid refrigerant to be directed from the outdoor unit to the first air conditioning unit, determine that a heating operation mode is active during a second time interval, and cause the vapor refrigerant to be directed from the outdoor unit to both the water heater and the first air conditioning unit.

According to an aspect of the present disclosure, there is disclosed a method of determining the use of hot water performed in a system including a water heater and an air handler. The method includes: sensing a temperature of influent flowing into the water heater; sensing a temperature of effluent flowing out of the air handler; calculating a temperature difference between the temperature of the influent and the temperature of the effluent; and determining whether hot water is used by calculating whether the temperature difference is greater than a predetermined value.

The disclosure provides a method, an apparatus, and a storage medium for controlling a heating system in a combined heat and power system. The method includes: establishing a load flow model of the heating system, in which the heating system includes pipelines and nodes; the nodes include loads and heating sources; the load flow model includes an objective function and constraints; the objective function for maximizing and minimizing an inlet water temperature of each load or each source; solving the load flow model to obtain an upper limit and a lower limit of the inlet water temperature of each load or each source; and controlling the inlet water temperature of each load or each source based on the upper limit and the lower limit of the inlet water temperature of each load or each source.

The present disclosure is directed to a hot water recirculation system with a return tee. The system includes a water heater, several supply lines, and a return tee. The hot water supply line is communicatively coupled to the water heater and at least one fixture and provides heated water from the water heater to the at least one fixture. The cold water supply line provides cold water from a cold water source to the water heater. Finally, the return line is communicatively coupled to the hot water supply line and delivers cooled water from the hot water supply line to the water heater. A return tee is communicatively coupled to the return line, the cold water supply line, and the water heater. This return tee provides cooled water from the return line and cold water from the cold water supply line to the water heater, which heats the water.