A heat-pump water heater includes a refrigerant circuit, a water circuit, and a controller. The refrigerant circuit includes a main circuit and a bypass circuit. The main circuit includes a compressor, a water heat exchanger, a first pressure-reducing device, an air heat exchanger, and an air-sending device. The bypass circuit includes a second pressure-reducing device. The water circuit includes a hot water tank, a water pump, and the water heater exchanger. In a night-time hot-water supply mode, the controller causes the water pump with a lowest frequency set in advance, causes the compressor with a lowest frequency set in advance, and stops the air-sending device.

A method for controlling an operating discharge pressure in a multi-purpose HVAC system including an outdoor unit, and an indoor unit, the HVAC system including a plurality of flow control valves configured to isolate a the indoor unit from the multi-purpose HVAC system, a compressor and a controller, operably coupled to a water heater module, the water heater module including at least one valve, the controller executing a method including operating the multi-purpose HVAC system in a water heating mode, monitoring the operating discharge pressure from the compressor; and generating a signal commanding at least one of the plurality of control valves to isolate the indoor unit from the outdoor unit and water heating module and direct high pressure refrigerant to the indoor unit when the operating discharge pressure is greater than or equal to a predetermined pressure value.

The disclosure discloses a multi-type air conditioner system including: an outdoor machine, a refrigerant pipe connected with an output end of the outdoor machine, a manifold connected with an input end of the refrigerant pipe, an indoor machine connected with an output end of the refrigerant pipe, and a controller connected respectively with the outdoor machine and the indoor machine through a shielded signal line, wherein the multi-type air conditioner system may further include: a pipe set including a composite pipe, a third cutoff valve, a third filter, a third electronic expanding valve, a fourth cutoff valve and a pipe control board. With the disclosure, heating can be provided by precisely controlling indoor temperature and effectively lower power consumption.

A heat pump apparatus includes: a refrigerant circuit configured to circulate refrigerant having flammability; a heat medium circuit configured to allow a heat medium to flow therethrough; a heat-medium heat exchanger configured to exchange heat between the refrigerant and the heat medium; an outdoor unit configured to accommodate the refrigerant circuit and the heat-medium heat exchanger; and an indoor unit configured to accommodate a part of the heat medium circuit, the outdoor unit including a refrigerant release valve, the refrigerant release valve being at least one of a pressure relief valve and an air purge valve which are provided in the heat medium circuit, the refrigerant release valve being provided outside a casing of the outdoor unit.

An air conditioning system includes a heat pump unit including a radiator usable with a refrigerant, a gas furnace unit including a heating section arranged to heat passing air, a blower arranged to generate an air flow that passes through the radiator and the heating section, a first temperature sensor provided in a room, and a controller configured to control each action of the heat pump unit, the gas furnace unit, and the blower. The temperature sensor detects an indoor temperature in the room. The controller causes the gas furnace unit to operate as a heat source unit when a difference value obtained by subtracting the indoor temperature from a set temperature is equal to or greater than a first threshold at startup, and causes the heat pump unit to operate as a heat source unit when the difference value is less than the first threshold at startup.

A method of and system for heating and/or cooling a fluid, the method comprising moving the fluid through a secondary side of a heat exchanger and controlling the temperature of a primary side of the heat exchanger such that the temperature of the primary side of the heat exchanger is maintained substantially at a determined temperature interval from a reference temperature which is a function of at least one of: a temperature of an inlet to the secondary side and a temperature of an outlet of the secondary side.

A heat pump and a control method thereof, the control method of the heat pump which heats a heated space through heat exchange between outdoor air and a refrigerant and heat exchange between the refrigerant and circulation water, includes calculating the maximum allowable frequency of a compressor based on the temperature of the outdoor air and the heating load of the heated space, calculating the mean operating frequency of the compressor while the compressor is operated at the calculated maximum allowable frequency, recalculating the maximum allowable frequency based on a result of comparison between the mean operating frequency and the maximum allowable frequency, and operating the compressor at the recalculated maximum allowable frequency, thereby improving coefficient of performance (COP) of the heat pump.

When a heating operation mode using a heating unit is specified and when a hot water supply request using the hot water in a hot water storage tank does not occur, an air conditioning apparatus transmits a first selection signal for selecting the heating unit to a three-way valve. When the heating operation mode is specified and when the hot water supply request occurs, the air conditioning apparatus transmits, to the three-way valve, a second selection signal for changing a destination of circulation of secondary refrigerant from the heating unit to a coil heat exchanger, and transmits an operation start signal to a refrigerant indoor unit.

Heat pump system (100) comprising a heat medium circuit (210,220,230,240,250,310,320,410,420,430,440,450,460) in turn comprising at least three heat exchanging means (314,315,315,422,433,452) between the heat medium and a respective heat source or sink selected from outdoor air, a water body, the ground, indoorair, pool water or tap water, a valve means (311,312,313,421,431,451) arranged to selectively direct the heat medium to at least two of said heat exchanging means, and a control means (500). The invention is characterized in that the heat pump system comprises temperature sensors (314a,314b;315a,315b;316a,316b;423,424,425;432,434,435) both upstream and downstream of at least one of said heat exchanging means, in that the system determines, based upon temperature measurement values comprising at least onevalue read from said sensors, to what heat exchanging means the heat medium is to be directed, and in that when heat medium is not directed to a certain heat exchanging means a measured temperature value is read upstream and downstream of the certain heatexchanging means, and in that an alert is set off in case the values differ by more than a predetermined value. The invention also relates to a method.

A storage type hot water supplying apparatus includes: a condenser having a refrigerant passage located at a hot water storage tank, the condenser being configured to condense refrigerant by exchanging heat between the refrigerant compressed by a compressor and water in the hot water storage tank; control circuitry configured to control a hot water storage operation, and a hot water supply detection sensor capable of detecting that a hot water supply operation is started, the hot water supply operation being an operation in which hot water in the hot water storage tank flows out of the hot water outlet and water flows into the hot water storage tank from the feed water inlet. The control circuitry is configured to increase an opening degree of the expansion valve when the hot water supply operation is started during the hot water storage operation.