Daikin Industries, Ltd.

Tatsuya Makino

Junichi Shimoda

Yoshiteru Nouchi

Hiroshi Nakashima

Ryouta Suhara

Yukako Kanazawa

Naoki Moroi

Shouhei Miyatani

Tsuyoshi Yamada

Yoshiaki Yumoto

You Tomiyama

Masashi Saitou

Keitarou Hoshika

Toshihiko Takayama

Takeshi Arai

A refrigeration apparatus includes a refrigerant circuit including a compressor, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger connected to each other, the refrigerant circuit being capable of executing at least a heating operation by circulating a refrigerant through the refrigerant circuit, and a control unit configured to start a defrosting operation for melting frost formed on the outdoor heat exchanger when a first defrosting start condition is satisfied in a case where a predetermined premise situation is not established and start the defrosting operation when a second defrosting start condition stricter than the first defrosting start condition is satisfied in a case where the predetermined premise situation is established. The predetermined premise situation is at least either a situation relating to unlikelihood of formation of frost on the outdoor heat exchanger progressing or a situation where a load of the heating operation is large.

Refrigeration apparatus with defrost during heating operation

Stress to be imposed on a compressor in reverse cycle operation is reduced. A cycle controller causes an outdoor heat exchanger to function as a condenser and an indoor heat exchanger to function as an evaporator when a reverse cycle executing condition is met, so that a refrigerant circulates in reverse of a heating cycle. A rotation speed controller adjusts a rotation speed of a compressor in a reverse cycle, depending on an index correlated with an amount of frost on the outdoor heat exchanger at a start of the reverse cycle. The rotation speed controller decreases the rotation speed of the compressor in the reverse cycle as the index at the start of the reverse cycle indicates that the amount of the frost on the outdoor heat exchanger is smaller.

Air conditioner with defrost control

A heat source-side heat exchanger fan blowing air to a heat source-side heat exchanger performing heat exchange with refrigerant compressed in a compressor is controlled. A current detected temperature at a current time is converted to obtain a current converted high pressure value at the current time. The current converted high pressure is a pressure of refrigerant inside a high pressure-side pipe of the compressor. The current detected temperature is a temperature detected by a temperature detector attached to the heat source-side heat exchanger. A past detected temperature is converted to obtain a past converted high pressure value at the past time. A speed of the heat source-side heat exchanger fan is determined using a corrected converted high pressure value. The corrected converted high pressure value is obtained by correcting the current converted high pressure value based on the past converted high pressure value.

Method of controlling heat source-side heat exchanger fan, and air conditioner

An air conditioning apparatus includes a refrigerant circuit performing an air-warming operation by circulating refrigerant through the compressor, indoor heat exchanger, expansion valve, and outdoor heat exchanger in order. The outdoor heat exchanger has flat perforated tubes arrayed vertically in multiple levels. The heat transfer tubes are sectioned into main and subordinate heat exchange parts. Upper and lower exit-entry spaces are formed in the outdoor heat exchanger. When an oil-accumulation-resolving criterion is met during the air-warming operation, low-refrigerant-circulation control, in which the refrigerant is circulated through the compressor, indoor heat exchanger, expansion valve, and outdoor heat exchanger in order, is performed for a predetermined time with an operating capacity of the compressor having been lowered to a predetermined capacity. The oil-accumulation resolving criterion is used to initiate an operation of defrosting the outdoor heat exchanger after the low-refrigerant-circulation control is performed.

Air conditioning apparatus

An air conditioning apparatus has a refrigerant circuit in which a compressor, a four-way switching valve, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger are interconnected. The outdoor heat exchanger uses multi-hole flat tubes as heat transfer tubes. When stopping a heating operation, the air conditioning apparatus performs pressure equalization control that switches the four-way switching valve from a heating cycle state to a cooling cycle state, thereafter stops the compressor, and equalizes the pressure in the refrigerant circuit.

An air-conditioning apparatus includes an outdoor unit, an indoor unit having an indoor heat exchanger, and a controller for executing a pump down operation. The outdoor unit has an accumulator of a capacity (Va), a compressor, an outdoor heat exchanger, an expansion valve, a large-diameter tube, which are joined by refrigerant pipes. The capacity (Vhi) of the indoor heat exchanger is greater than the capacity (Vho) of the outdoor heat exchanger. The large-diameter tube, which is larger in diameter than the refrigerant pipes, is provided so that the capacity (Vt) of the large-diameter tube satisfies the formula: capacity (Vt)&#x3e;capacity (Vhi)&#x2212;capacity (Vho)&#x2212;capacity (Va).

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Sakai, Japan

Tatsuya Makino