Mitsubishi Electric Corporation

Hiroyuki Okano

Osamu Morimoto

Yoji Onaka

Takanori Koike

Takashi Matsumoto

Hiroki Maruyama

Kosuke Miyawaki

Takeshi Hatomura

Naofumi Takenaka

Hirofumi Koge

Takuya Matsuda

Naomichi Tamura

Hiroaki Asanuma

Kazuki Okochi

Kosuke Tanaka

Yuji Motomura

Katsuhiro Ishimura

Shigeyoshi Matsui

Hiroki Murakami

Satoru Yanachi

Kazuyoshi Shinozaki

Tadashi Ariyama

Rihito Adachi

Hiroaki Nakamune

Tomoki Inagaki

Shinji Oka

Eito Saito

An air-conditioning apparatus includes an outdoor unit and a relay unit. The outdoor unit includes a compressor compressing and discharging refrigerant and a heat-source-side heat exchanger performing heat exchange between the refrigerant and outside air. The relay unit and the outdoor unit forms a refrigerant circuit. The outdoor unit includes first and flow switching devices each switching an associated flow passage for the refrigerant between a plurality of flow passages, according to an operation mode. An outflow pipe and an inflow pipe through which refrigerant flows from the outdoor unit to the relay unit and from the relay unit into the outdoor unit, respectively, are between the outdoor unit and the relay unit. The first flow switching device is connected to the compressor, the second flow switching device, and the outflow pipe. The second flow switching device is connected to the first flow switching device and the inflow pipe.

Air-conditioning apparatus

An air-conditioning apparatus includes a refrigerant circuit in which a compressor, a refrigerant flow switching device, a heat source side heat exchanger, an expansion device, a heat medium heat exchanger, and an accumulator are connected, a heat medium circuit in which a pump, the heat medium heat exchanger, a heat medium flow control device, and a load side heat exchanger are connected, at least one or more bypass pipes provided in the refrigerant circuit so that the refrigerant discharged from the compressor bypasses at least either one of the heat source side heat exchanger and the heat medium heat exchanger, a bypass opening and closing device provided at the bypass pipe, and a controller configured to control the bypass opening and closing device to carry out a start-up control function of causing low-pressure gas refrigerant with a high degree of superheat to flow into the accumulator.

A liquid level detector includes: a vertically-mounted accumulator that stores refrigerant; a heater that heats the accumulator; a temperature detector that detects a surface temperature of the accumulator; a pressure detector that detects a pressure of the refrigerant in the accumulator; and a controller. The controller detects a position of a liquid surface of the refrigerant in the accumulator based on a surface temperature of the accumulator detected by the temperature detector when the accumulator is heated by the heater, and a pressure of the refrigerant in the accumulator detected by the pressure detector.

Liquid level detector and air conditioning apparatus including the liquid level detector

A heat exchanger includes a plurality of heat transfer tubes, a liquid header distributor, and a gas header distributor. The heat transfer tubes include U-shaped bent portions. The heat exchanger includes a heat exchanger core. A relationship between the liquid header distributor and the plurality of heat transfer tubes is established such that 9≤ζ is satisfied, where Lh [m] is the length of the liquid header distributor, Lb [m] is the length of the shortest one of the heat transfer tubes, and ζ is the ratio of the length Lb of the shortest heat transfer tube to the length Lh of the liquid header distributor and is expressed by ζ=Lb/Lh.

Outdoor unit and air-conditioning apparatus

An air-conditioning apparatus including heat source apparatuses each including a compressor and an accumulator includes: a refrigerant amount calculation unit that calculates an amount of the refrigerant accumulated in the accumulator in one of the heat source apparatuses that is to be controlled; a refrigerant differential amount calculation unit configured to calculate, when the number of the heat source apparatuses is two, a differential amount between the calculated amount and an amount of the refrigerant in the accumulator in the other heat source apparatus, and calculate, when the number of the heat source apparatuses is three or more, a differential amount between the calculated amount of the refrigerant and an average amount of amounts of the refrigerant accumulated in the accumulators in the heat source apparatuses; and a liquid equalization control unit that controls the heat source apparatus to be controlled, based on the calculated differential amount.

Air-conditioning apparatus and method of controlling the same

The air-conditioning apparatus includes the plurality of heat source apparatuses; a plurality of indoor units each including an indoor heat exchanger and each configured to perform one of cooling and heating operations; a relay device connected to the heat source apparatuses by a high pressure pipe and a low pressure pipe and configured to distribute refrigerant flowing therein from the heat source apparatuses to the plurality of indoor units; and a controller configured to control operations of the heat source apparatuses. The relay device includes a relay device temperature detecting unit configured to detect a temperature of the refrigerant flowing through the bypass pipe. During the heating main operation, the controller changes an opening degree of each of the outdoor side expansion devices based on the temperature detected by the relay device temperature detecting unit.

A header includes a plurality of branch tubes and a header manifold. If refrigerant flowing into the header manifold forms a pattern of annular flow or churn flow, tips of the branch tubes inserted into the header manifold pass through a liquid-phase portion having a thickness &#x3b4; [m] and reach a gas-phase portion. The thickness &#x3b4; [m] of the liquid-phase portion is defined as &#x3b4;=G&#xd7;(1&#x2212;x)&#xd7;D/(4&#x3c1;&#xd7;U), where G is a flow speed [kg/(ms)] of the refrigerant, x is a quality of the refrigerant, D is an inside diameter [m] of the header manifold, &#x3c1;is a liquid density [kg/m] of the refrigerant, Uis a reference apparent liquid speed [m/s] that is a maximum value within a range of variation in an apparent gas speed of the refrigerant flowing into a flow space of the header manifold. The reference apparent liquid speed U[m/s] is defined as G(1&#x2212;x)/&#x3c1;.

Air-conditioning apparatus and method of using air-conditioning apparatus

The air-conditioning apparatus includes a heat exchanger including a plurality of heat transfer tubes and a header manifold an axial fan and a refrigerant circuit. When the distance from the center of the flow space in the horizontal plane is represented on a scale of 0 to 100%, where 0% represents the center of the flow space and 100% is the position of the wall surface of the header manifold, among the plurality of branch tubes located within a height range that allows the blade to rotate, the majority of the branch tubes located at or below the height of the boss are connected to the header manifold such that their distal ends are positioned at 0 to 50% of the distance from the center, and the majority of the branch tubes located above the height of the boss are connected to the header manifold such that their distal ends are positioned at more than 50% of the distance from the center.

An air-conditioning apparatus that includes a compressor, a flow switching device, an outdoor heat exchange unit, an expansion section and an indoor heat exchanger, which are connected by pipes, in which the outdoor heat exchange unit includes a first outdoor heat exchanger, a first flow rate control device, a second outdoor heat exchanger, a second flow rate control device, a bypass pipe, the second outdoor heat exchanger, the second flow rate control device, a third flow rate control device, and a flow control device.

A refrigerant distributor branches refrigerant flowing in a refrigerant circuit into three, and includes a first bifurcate flow divider including a first pipe portion forming one inflow port, a second pipe portion and a third pipe portion forming two outflow ports communicating with the inflow port of the first pipe portion, and a second bifurcate flow divider including a fourth pipe portion forming one inflow port, and a fifth pipe portion and a sixth pipe portion forming two outflow ports communicating with the inflow port of the fourth pipe portion. The outflow port of the third pipe portion and the inflow port of the fourth pipe portion communicate with each other, and an angle &#x3b8; formed by a first plane passing through the first bifurcate flow divider and a second plane passing through the second bifurcate flow divider is between 60 and 120 degrees.

Refrigerant distributor and air-conditioning apparatus

In a refrigerant circuit of an air conditioning device, an upper heat source side heat exchanger having a large heat load and a lower heat source side heat exchanger having a small heat load are connected in parallel between an expansion device and a suction side of a compressor. Additionally, the refrigerant circuit of the air conditioning device is provided with a branch circuit configured to distribute refrigerant to each of the upper heat source side heat exchanger and the lower heat source side heat exchanger, and the branch circuit is configured to supply the upper heat source side heat exchanger with refrigerant of lower quality than that of the refrigerant supplied to the lower heat source side heat exchanger.

Refrigerant circuit

A refrigeration cycle apparatus includes a refrigerant circuit, through which refrigerant is circulated, including a compressor, a heat source side heat exchanger, a first expansion device, and a load side heat exchanger, a controller controlling the refrigerant circuit, and a bypass pipe that branches off from a high-pressure pipe extending from the compressor to the first expansion device and that is connected to a low-pressure pipe on a suction side of the compressor. The apparatus further includes a precooling heat exchanger that is provided in the bypass pipe and that cools the refrigerant diverted to the bypass pipe, a second expansion device that is provided in the bypass pipe and that reduces a pressure of the refrigerant cooled by the precooling heat exchanger, and a refrigerant cooler that is provided in the bypass pipe and that cools the controller with the refrigerant reduced in pressure by the second expansion device.

Refrigeration cycle apparatus

A liquid level detection device detecting a liquid level of a liquid in a container includes a heater configured to heat the container, a plurality of temperature sensors provided at different heights of the container, and configured to detect a surface temperature of the container, and a controller configured to detect the liquid level of the liquid in the container, based on the surface temperature of the container detected by the plurality of temperature sensors when the heater is caused to heat.

Liquid level detection device, accumulator, and air-conditioning apparatus

A heat exchanger includes first and second headers connected to end portions of heat transfer tubes. The second header includes a header pipe defining a flow space that communicates with the heat transfer tubes and, when the heat exchanger acts as an evaporator, allows refrigerant in a two-phase gas-liquid state to pass through the flow space into the heat transfer tubes. A bypass pipe is disposed between an entrance portion and the first header. The entrance portion has an entrance distance L between a connection end portion connected to a refrigerant pipe and a central axis of the bypass pipe. The entrance distance L of the entrance portion satisfies L&#x2265;5di, where di is an inner diameter of a flow space of the header pipe on an orthogonal plane orthogonal to a direction of refrigerant flow. The bypass pipe is inserted in the flow space of the entrance portion.

Heat exchanger and air-conditioning apparatus

A refrigeration cycle apparatus includes a refrigerant circuit, a controller, a bypass pipe, a refrigerant cooler, a second expansion device, and a controller temperature sensor. In a case where a temperature measured by the controller temperature sensor is lower than or equal to a set temperature in a state where an opening degree of the second expansion device is controlled to an instruction opening degree that is lower than or equal to a set opening degree, the controller is configured to perform foreign substance release control where the controller is configured to increase the opening degree of the second expansion device and then is configured to return the opening degree of the second expansion device to the instruction opening degree.

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Tokyo, Japan

Hiroyuki Okano