An apparatus includes a compressor, a first heat exchanger, a reheater, a first valve, a second heat exchanger, and a blower. The compressor compresses a refrigerant. The blower moves air proximate the second heat exchanger to the reheater. During a first mode of operation: the first heat exchanger removes heat from a first portion of the refrigerant from the compressor, the first valve opens such that a second portion of the refrigerant from the compressor flows to the reheater, the second heat exchanger uses the first portion of the refrigerant from the first heat exchanger and the second portion of the refrigerant from the reheater to cool air proximate the second heat exchanger, and the reheater uses the second portion of the refrigerant from the compressor to heat the air moved by the blower.

An apparatus includes a compressor, a first heat exchanger, a reheater, a first valve, a second heat exchanger, and a blower. The compressor compresses a refrigerant. The blower moves air proximate the second heat exchanger to the reheater. During a first mode of operation: the first heat exchanger removes heat from a first portion of the refrigerant from the compressor, the first valve opens such that a second portion of the refrigerant from the compressor flows to the reheater, the second heat exchanger uses the first portion of the refrigerant from the first heat exchanger and the second portion of the refrigerant from the reheater to cool air proximate the second heat exchanger, and the reheater uses the second portion of the refrigerant from the compressor to heat the air moved by the blower.

Apparatus and method for heating/cooling buildings and other facilities. An elongate pipe filled with water or other fluid medium forms a thermal gradient header having temperature zones that are progressively warmer towards one end and cooler towards the other. Multiple heating/cooling systems are connected to the header so as to draw fluid from zones that are closest in temperature to the optimal intake temperature of each system, and to discharge fluid back to the header at zones that are closest to the temperature to the optimal output temperature of each system, allowing each heating/cooling system to take advantage of the thermal output of other systems. The pipe forming the thermal gradient header may be routed back and forth in the facility to define a series of legs containing the different temperature zones. A boiler or other source may supply makeup heat to the thermal gradient header, and excess heat may be sent from the header to a ground field or other thermal reservoir for later use.

Apparatus and method for heating/cooling buildings and other facilities. An elongate pipe filled with water or other fluid medium forms a thermal gradient header having temperature zones that are progressively warmer towards one end and cooler towards the other. Multiple heating/cooling systems are connected to the header so as to draw fluid from zones that are closest in temperature to the optimal intake temperature of each system, and to discharge fluid back to the header at zones that are closest to the temperature to the optimal output temperature of each system, allowing each heating/cooling system to take advantage of the thermal output of other systems. The pipe forming the thermal gradient header may be routed back and forth in the facility to define a series of legs containing the different temperature zones. A boiler or other source may supply makeup heat to the thermal gradient header, and excess heat may be sent from the header to a ground field or other thermal reservoir for later use.

A multi-split air-conditioner and an outdoor unit system thereof are provided. The outdoor unit system includes: a compressor (1) having a gas outlet (a) and a gas inlet (b); an outdoor heat exchanger (2) having an inlet (c) and an outlet (d); a switching assembly (3) having first to sixth ports, wherein the first port (e) is connected with the gas outlet (a) of the compressor (1), the second port (f) is connected with the gas inlet (b) of the compressor (1), the third port (g) is connected with the inlet (c) of the outdoor heat exchanger (2), the fourth port (h) is connected with the outlet (d) of the outdoor heat exchanger (2), the fifth port (i) is connected with an inlet pipe (4) and the sixth port (j) is connected with an outlet pipe (5).

An air conditioner includes an outdoor unit, a plurality of mode change devices including at least one mode changer including a branch duct and a changing valve, and configured to receive a control signal from the outdoor unit to control an operation of the at least one mode changer. A plurality of indoor units are connected to the outdoor unit or the plurality of mode change devices. The outdoor unit may determine an operation mode to operate the plurality of mode change devices a plurality of times. Each of the plurality of indoor units may detect a temperature change of an indoor heat exchanger in response to the operation of the mode change devices, to determine the number of connected mode changers and a connectable mode changer candidate group based on the temperature change of the indoor heat exchanger.

A heat exchange unit that performs at least one of a cooling and a heating of a liquid medium that is sent to a utilization side equipment includes: a heat exchanger that exchanges heat between a flammable refrigerant and the liquid medium; an electric component as an ignition source; a casing that accommodates the heat exchanger and the electric component; and a gas detection sensor with a detection element that is disposed below the electric component and that detects a gas from the flammable refrigerant.

A heat exchange unit that performs at least one of a cooling and a heating of a liquid medium that is sent to a utilization side equipment includes: a heat exchanger that exchanges heat between a flammable refrigerant and the liquid medium; an electric component as an ignition source; a casing that accommodates the heat exchanger and the electric component; and a gas detection sensor with a detection element that is disposed below the electric component and that detects a gas from the flammable refrigerant.

A cooling and heating control method of a multi type air conditioner in which a target pressure of a compressor is adjusted based on conditions of respective indoor units so as to reduce power consumption is provided. The cooling control method includes determining the indoor unit desired to execute power saving control, judging whether or not a difference between a temperature of a space in which the indoor unit desired to execute power saving control is located and a set temperature of the indoor unit is less than a reference value, raising a target evaporation temperature of the indoor unit upon judging that the difference is less than the reference value, comparing an evaporation temperature of the indoor unit with the raised target evaporation temperature, and raising an evaporation pressure of a compressor, when the evaporation temperature of the indoor unit is lower than the raised target evaporation temperature.

When indoor units are performing a cooling operation, an air-conditioning apparatus controls four flow passage switching valves, for example a first solenoid valve, a second solenoid valve, a third solenoid valve, and a fourth solenoid valve, so that a number of intermediate heat exchangers operating as evaporators is greater than in a cooling main operation. During the cooling main operation, a target value for suction pressure or evaporating temperature at a compressor is set equal to or lower than that in a case in which the indoor units are performing the cooling operation, and a frequency of the compressor and a capacity of a heat-source-side heat exchanger are controlled.