Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Noriho Okaza

Kazuo Nakatani

Yoshikazu Kawabe

Yuji Inoue

Fumitoshi Nishiwaki

Akira Hiwata

Masami Funakura

Yuuichi Yakumaru

Yuji Yoshida

Masaaki Suzuki

Hiroshi Hasegawa

Takashi Sawada

Hidenobu Shintaku

Mitsuhiro Ikoma

Masahiro Ohama

Yasuhiko Isayama

Takayuki Takatani

Yuuki Yamaoka

Masato Mekata

Shigeo Aoyama

Shunji Moriwaki

A liquid circulation heating system performs air-heating by heating a liquid to produce a heated liquid and releasing heat of the heated liquid from a heating radiator. This liquid circulation heating system includes: a heat pump circuit for circulating a refrigerant, having a radiator for heating the liquid by radiating heat from the refrigerant; and a solar heating apparatus for heating the liquid by solar heat. In this liquid circulation heating system, a first passage passing through the radiator and a second passage passing through the solar heating apparatus are formed as passages through which the liquid flows to produce the heated liquid.

Liquid circulation heating system

It is an object of the present invention to reduce the constraint that the density ratio is constant as small as possible, and to obtain high power recovering effect in a wide operation range. A refrigeration cycle apparatus uses carbon dioxide as refrigerant and has a compressor, anoutdoor heat exchangerevaporator, an expander andan indoor heat exchangera radiator. An injection circuit for introducing high pressure refrigerant is provided in a halfway of an expansion process of said expander.

Refrigeration cycle apparatus

In a refrigeration cycle apparatus having an expansion mechanism, a method to swiftly generate a pressure difference upstream and downstream of the expansion mechanism of, thereby enhancing the starting performance of the refrigeration cycle apparatus The apparatus has a compression mechanism, a utilizing-side heat exchange, an expansion mechanism for recovering power, and a heat source-side heat exchanger. The revolution number of the heat source fluid transfer means is made smaller than a target revolution number or the heat source fluid transfer means is stopped during a predetermined time after the compression mechanism is started. When the compression mechanism is started, the pressure difference can be generated upstream and downstream of the expansion mechanism for a short time, the operation of the expansion mechanism does not become unstable, vibration and noise can be prevented, and the refrigeration cycle apparatus can swiftly be started.

Start-up control method for refrigeration cycle apparatus and refrigeration cycle control apparatus using the same

In a refrigerating cycle device using carbon dioxide as a refrigerant, there exists a problem that the provision of a receiver at a low-pressure side increases cost and volume due to a pressure resistance design necessary for ensuring safety. By adjusting a refrigerant holding quantity of a first heat exchanger in such a manner that a refrigerant pressure of the first heat exchangeris changed by operating a first decompressorand a second decompressor, an imbalance of a refrigerant quantity between time for space cooling and time for heating or dehumidifying can be alleviated and hence, it is possible to perform an operation of the refrigerating cycle device with high efficiency with a miniaturized receiver or without providing the receiver.

Refrigerating cycle device

An air conditioner for a vehicle includes a refrigerant cycle having an evaporator which is disposed in a blowing duct and cools air by refrigerant evaporation in the blowing duct; a compressor setting the evaporated refrigerant at a high temperature and high pressure; a refrigerant-to-water heat exchanger heating cooling water by heat transfer from the refrigerant discharged from the compressor; and an expansion device decompressing the refrigerant discharged from the refrigerant-to-water heat exchanger. The air conditioner also includes a cooling water cycle having a heater core which is disposed on the downstream side of the evaporator; a radiator cooling the cooling water; a pump circulating the cooling water cooled by the radiator; a power engine cooled by the cooling water fed by the pump; and the refrigerant-to-water heat exchanger. The refrigerant cycle performs cooling for dehumidification by performing the operation of heating.

Air conditioner

In the case of gas injection, a discharging temperature is not reduced sufficiently, and if an amount of injection is increased, a liquid refrigerant flows into a cylinder and the liquid is compressed, and the reliability can not be ensured. A refrigerator wherein at least a compressor, a radiator, a first throttle apparatus and an evaporator are connected to one another in an annular form to constitute a main circuit of a refrigeration cycle, a refrigerant which can be brought into a supercritical state by the radiator during operation is charged into the refrigeration cycle, the refrigerator comprises an injection pipe for injecting the refrigerant on the side of an outlet of the radiator into a cylinder of the compressor.

Refrigerator

To prevent heat transfer inhibition and an increase in pressure loss due to refrigerating machine oil discharged into a cycle, and to provide a compact and highly efficient refrigerating cycle apparatus using carbon dioxide gas (CO). In a refrigerating cycle apparatus having at least a compressor, a radiator, a decompressor, a vaporizer and piping for successively connecting them, and provided with a refrigerant circuit in which refrigerant circulates in the compressor, the radiator, the decompressor, the vaporizer and the piping, carbon dioxide gas (CO) is enclosed as said refrigerant, and the drop in heat transfer rate and the increase in pressure loss in the heat exchanger can be restrained to very low levels by keeping oil enclosing volume in the refrigerant circuit to the quantity of carbon dioxide gas (CO) enclosed as refrigerant (weight %) to less than 40 weight % and more than 0, resulting in practical elimination of the increase in size and the impact on the drop in efficiency of the heat exchanger.

A refrigeration cycle apparatus using carbon dioxide as a refrigerant has a compressor, an outdoor heat exchanger, an expander, an indoor heat exchanger and an auxiliary compressor. The auxiliary compressor is driven by power recover by the expander. When refrigerant flows using the indoor heat exchanger as an evaporator, a discharge side of the auxiliary compressor becomes a suction side of the compressor, and when refrigerant flows using the indoor heat exchanger as a gas cooler, a discharge side of the compressor becomes a suction side of the auxiliary compressor.

It is an object of the invention to provide an inexpensive double-pipe heat exchanger having high performance and comprising an inner pipe and an outer pipe which constitute a double pipe without adding a heat-transfer facilitating material such as an inner fin. In the double-pipe heat exchanger having the inner pipe and the outer pipe, the outer pipe is dented from its outside toward its inside, thereby forming a plurality of projections which are dented toward the inner pipe. Examples of shapes of the projection are substantially conical shape, substantially truncated shape, substantially spherical surface shape, substantially cylindrical shape, substantially elliptic cylindrical shape and the like. The projections are disposed helically or in a staggered configuration such as to surround the inner pipe. With this structure, only by subjecting the outer pipe to simple working such as press working, it is possible to increase the turbulent flow of fluid flowing between the inner pipe and the outer pipe, and to facilitate heat transfer from fluid flowing in the inner pipe to fluid flowing between the inner pipe and the outer pipe.

Double-pipe heat exchanger

It is an object of the present invention to reduce the constraint that the density ratio is constant as small as possible, and to obtain high power recovering effect in a wide operation range. A refrigeration cycle apparatus uses carbon dioxide as refrigerant and has a compressor, an outdoor heat exchanger, an expander and an indoor heat exchanger. An injection circuit for introducing high pressure refrigerant is provided in a halfway of an expansion process of said expander.

Refrigeration-cycle equipment wherein an oil separator is installed as a refrigerant vessel in a part of the high-pressure-side circuit. A linear compressor of an oil-less type or an oil-poor type is used. Alternatively, the quantity of the COrefrigerant filled in the circuit is 0.25 kg or less per liter on the basis of the total internal volume of the circuit.

Refrigeration-cycle equipment

It is an object of the present invention to reduce the constraint that the density ratio is constant as small as possible, and to obtain high power recovering effect in a wide operation range by using an expander which is operated in accordance with a flowing direction of refrigerant. A determining method of a high pressure of a refrigeration cycle apparatus in which a refrigeration cycle uses carbon dioxide as refrigerant and has a compressor, an outdoor heat exchanger, an expander and an indoor heat exchanger, and the refrigeration cycle including a bypass circuit provided in parallel to said expander, and a control valve which adjusts a flow rate of refrigerant flowing through said bypass circuit, said compressor being driven by power recover by said expander, wherein if an optimal high pressure of a first refrigeration cycle flowing through said expander and a second refrigeration cycle flowing through said bypass circuit is defined as Ph, and a bypass amount ratio flowing through said bypass circuit in said Ph is defined as Rb, and a maximum refrigeration cycle efficiency of said first refrigeration cycle in said Ph is defined as COPe, and a maximum refrigeration cycle efficiency of said second refrigeration cycle in said Ph is defined as COPb, the optimal high pressure Ph which maximizes (1&#x2212;Rb)&#xd7;COPe+Rb&#xd7;COPb is determined.

Determining method of high pressure of refrigeration cycle apparatus

To provide a refrigerating cycle apparatus which uses carbon dioxide as a working medium, in which a problem associated with reliability arisen from introduction of water into a refrigeration cycle has been solved. Carbonic acid produced by a reaction of carbon dioxide or a mixed refrigerant including carbon dioxide and water is efficiently removed by providing a flow channel of the refrigeration cycle with a carbonic acid trapping agent, and consequently, the refrigerating cycle apparatus with high reliability which can prevent deterioration of a carbon dioxide refrigerant, decomposition of a refrigeration oil, corrosion of metal components or the like is constructed.

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Shiga, Japan

Noriho Okaza