Daikin Industries, Ltd.

Yasushi Hori

Shinri Sada

Shinya Matsuoka

Osamu Tanaka

Yoshiyuki Tsuji

Mariko Takakura

Tetsushi Maeda

Hiromune Matsuoka

Masahiro Honda

Masahiro Oka

Kazuhide Mizutani

Junya Minami

Yuusuke Oka

Toru Inazuka

Keiji Ishida

Takashi Matsuzaki

Shigeaki Umeyama

Ryota Takechi

An air conditioning system includes an air conditioning device, a detector, and an alarm. The air conditioning device has a control unit and conditions air in an indoor space. The detector detects the concentration of refrigerant in the indoor space. The alarm notifies of refrigerant leakage in the indoor space. The detector or the alarm transmits information indicating whether or not the detector and the alarm are connected to each other in a wired or wireless manner, to the control unit. The control unit inhibits operation of the air conditioning device when the information indicates that the detector and the alarm are not connected to each other in the wired or wireless manner.

Air conditioning system, operation control method therefor, and operation control device for air conditioning system

In an air conditioning apparatus, an expansion valve is determined to be in a fully closed state when a refrigerant temperature in an outlet of an indoor heat exchanger and a refrigerant temperature in an inlet or an intermediate part of the indoor heat exchanger satisfy a closed-valve condition. The temperature in the outlet is detected by a gas-side temperature sensor. The temperature in the inlet or the intermediate part is detected by a liquid-side temperature sensor. The closed-valve condition is in relation to a refrigerant evaporation temperature obtained by converting a refrigerant pressure in an intake side of a compressor to a refrigerant saturation temperature, and in relation to an air temperature of an air-conditioned space cooled by the indoor heat exchanger. The pressure in the intake side is detected by an intake pressure sensor. The air temperature is detected by an indoor temperature sensor.

Conditioner determining a closed condition of an expansion valve

A controller of an air conditioning apparatus performs a start/stop frequency-reducing rotation speed control in which the rotation speed of a compressor is controlled based on request values from indoor units requesting a decrease in air conditioning capacity, disregarding request values from indoor units requesting an increase in air conditioning capacity, when each indoor temperature at all indoor units performing air conditioning operation is within a scope of a prescribed threshold temperature range surrounding a target indoor temperature at each indoor unit performing air conditioning operation.

Air conditioning apparatus

An air conditioner includes a refrigerant circuit that includes a heat source heat exchanger configured such that refrigerant flows in from below and flows out from above when the heat source heat exchanger functions as an evaporator of the refrigerant and a plurality of utilization heat exchangers. When the heat source heat exchanger is caused to function as an evaporator, the refrigerant discharged from a compression mechanism is bypassed to an intake side of the compression mechanism via a first bypass circuit, the heat source heat exchanger is caused to function as a condenser, and an expansion valve is closed, whereby refrigerating machine oil accumulating inside the heat source heat exchanger is returned to the intake side of the compression mechanism from a lower portion of the heat source heat exchanger via an oil returning circuit.

Air conditioner with oil recovery function

A refrigeration system to increase the subcooling degree of refrigerant flowing through a main refrigerant circuit is provided. The refrigeration system is configured such that a portion of the refrigerant flowing through the main refrigerant circuit can be made to bypass the remainder of the main refrigerant circuit in a bypass refrigerant circuit so as to be returned to the intake side of a compressor and to be used to cool the refrigerant flowing through the main refrigerant circuit to a subcooled state.

Refrigeration system

The present invention is capable of eliminating the line unit in an air conditioner that includes a plurality of heat source units, and hold increases in onsite line construction to a minimum while making it possible to adjust the amount of refrigerant in the air conditioner. The air conditioner includes a plurality of heat source units, a refrigerant liquid junction line and a refrigerant gas junction line, user units, and a refrigerant supply circuit. The refrigerant supply circuit is used in situations in which some of the plurality of heat source units stop operating in response to the operational burden of the user units, and is formed from refrigerant removal lines that remove refrigerant that accumulates inside stopped heat source units to the exterior thereof, and an oil equalization line and oil removal lines that connect the refrigerant removal lines of each stopped heat source unit and the intake sides of the compression mechanisms of the operating heat source units.

Air conditioner

The present invention provides an oil equalizing circuit that can improve the reliability of the oil supply to the compression mechanisms in a refrigeration system provided with a plurality of compression mechanisms. The compressor group of the air conditioning system is equipped chiefly with first, second, and third compressors and an oil equalizing circuit. The oil equalizing circuit is equipped with the first, second and third oil separators provided on the discharge sides of the compressors; first, second, and third oil return pipes connecting the oil separators to the intake sides of the compressors; a communication pipe for allowing the oil return pipes to communicate with one another; first, second, and third oil ON-OFF switching mechanisms provided downstream of the parts where the oil return pipes connect to the communication pipe; and first, second, and third pressure reducing mechanisms provided upstream of the parts where the oil return pipes connect to the communication pipe.

Compression mechanism oil equalizing circuit, refrigeration system heat source unit, and refrigeration system provided with the same

A compressor (,), a heat releasing element (,A) of a heat exchanger (,) for heating, an electromotive expansion valve (,), and a heat absorbing element (,A) of a heat exchanger (,) for cooling are connected to each other to constitute a primary refrigerant circuit. A pump (,), a heat absorbing element (,B) of the heat exchanger (,) for heating, a first indoor heat exchanger (,), an electromotive expansion valve (,), a second indoor heat exchanger (,), and a heat releasing element (,B) of the heat exchanger (,) for cooling are connected to each other to compose a secondary refrigerant circuit (,). A liquid refrigerant ejected from the pump (,) is evaporated in the heat absorbing element (,B) of the heat exchanger (,) for heating, reduced in pressure by the electromotive expansion valve (,), and evaporated in the second indoor heat exchanger (,). Thereafter, the gas refrigerant is condensed in the heat releasing element (,B) of the heat exchanger (,) for heating to be returned to the pump (,).

Refrigerating plant

A heat exchanger (,) on the secondary heat source, which exchanges heat with a heat exchanger (,) on the primary heat source in a primary cooling circuit (A), is connected with an indoor heat exchanger (,) through a gas pipe (,) and a liquid pipe (,). A tank (T) storing a liquid cooling medium is connected at its lower end to the liquid pipe (,) and its upper end to a pressure adjustment mechanism (,). Check valves (CV,and CV,) are disposed on both sides of the connecting point of the tank (T) with respect to the liquid pipe (,). The internal pressure of the tank (T) is changed over alternately between a high pressure state and a low pressure state by the pressure adjustment mechanism (,) so that the liquid cooling medium is supplied to the indoor heat exchanger (,) at the time of the high pressure operation, and the liquid cooling medium is recovered from the heat exchanger (,) on the secondary side to the tank (T) and is circulated by a secondary cooling circuit (B) at the time of the low pressure operation.

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Sakai, Japan

Yasushi Hori