Daikin Industries, Ltd.

Daikin Kogyo Co., Ltd.

Nippon Electric Co., Ltd.

Katsumi Sakitani

Masakazu Okamoto

Tetsuya Okamoto

Eiji Kumakura

Michio Moriwaki

Masanori Masuda

Kazuo Miura

Shoichi Taneya

Satoshi Noguchi

Yume Inokuchi

Hirofumi Higashi

Yoshinari Sasaki

Shigeharu Taira

Kazutaka Hori

Satoru Fujimoto

Satoshi Ishikawa

Yoon M Kang

Tadashi Ogura

Shinichiro Shinozaki

Shigehiro Uemura

Takekazu Obitani

Takahiro Uematsu

Youichi Oonuma

Shigeru Mori

Eiji Kamakura

Takashi Maekawa

Tetsuro Tajima

Makoto Hiroyasu

Ryuzaburo Yajima

A compressor and an expander are provided in a refrigerant circuit of an air conditioner. In the compressor, refrigerator oil is supplied from an oil reservoir to a compression mechanism. In the expander, the refrigerator oil is supplied from an oil reservoir to an expansion mechanism. Internal spaces of a compressor casing and an expander casing communicate with each other through an equalizing pipe. An oil pipe connecting the compressor casing and the expander casing is provided with an oil amount adjusting valve operated on the basis of an output signal of an oil level sensor. When the oil amount adjusting valve is opened, the oil reservoir in the compressor casing and the oil reservoir in the expander casing communicate with each other to allow the refrigerator oil to flow through the oil pipe.

Refrigerating apparatus

In a compression/expansion unit () serving as a fluid machine, both of a compression mechanism () and an expansion mechanism () are contained in a single casing (). A shaft () coupling the compression mechanism () to the expansion mechanism () has an oil feeding channel () formed therein. Refrigerating machine oil accumulated at the bottom of the casing () is sucked up into the oil feeding channel () and fed to the compression mechanism () and the expansion mechanism (). The refrigerating machine oil fed to the expansion mechanism () is discharged from the expansion mechanism () together with the refrigerant after expansion, flows through the refrigerant circuit and then flows back to the compression mechanism () in the compression/expansion unit ().

Fluid machine

A fluid machine includes a casing, a compression mechanism for compressing refrigerant, an expansion mechanism for expanding refrigerant, and a rotary shaft connecting the compression mechanism and the expansion mechanism. The compression mechanism, the expansion mechanism and the rotary shaft are disposed in the casing. A heat insulator partitions an internal space of the casing into a first space with the expansion mechanism disposed therein and a second space with the compression mechanism disposed therein. The rotary shaft passes through the heat insulator. An elastically deformable seal element seals a clearance between an outer periphery of the heat insulator and an inner periphery of the casing.

A refrigerant circuit () of an air conditioner () includes a compressor () and an expander (). In the compressor (), refrigerator oil is supplied from an oil reservoir () to a compression mechanism (). In the expander (), the refrigerator oil is supplied from an oil reservoir () to an expansion mechanism (). The inner pressures of the compressor casing () and the expander casing () are the high pressure and the low pressure of the refrigeration cycle, respectively. An oil adjusting valve () is provided in an oil pipe () connecting the compressor casing () and the expander casing (). The oil amount adjusting valve () is operated on the basis of an output signal of an oil level sensor (). When the oil amount adjusting valve () is opened, the refrigerator oil flows from the oil reservoir () in the compressor casing () toward the oil reservoir () in the expander casing () through the oil pipe ().

In a refrigerant circuit (), a compressor () and an expander () are provided separately. An expander casing () is connected to a delivery pipe () of the compressor () and high pressure refrigerant passes through the inside of the expander casing (). Therefore, the compressor casing () and the expander casing () are equalized in their internal pressure. An oil distribution pipe () for connection of an oil sump () of the compressor () and an oil sump () of the expander () is provided with an oil regulating valve (). The oil regulating valve () is controlled in response to a signal outputted from an oil level sensor (). When the oil regulating valve () is opened, the oil sump () within the compressor casing () and the oil sump () within the expander casing () fluidly communicate with each other whereby refrigeration oil travels through the oil distribution pipe ().

Refrigeration system

A rotary type expander is provided with two rotary mechanism parts which differ from each other in displacement volume. The outflow side of the first rotary mechanism part of small displacement volume is fluidly connected to the inflow side of the second rotary mechanism part of large displacement volume. The processes by which the volume of a first low-pressure chamber in the first rotary mechanism part decreases and the volume of a second high-pressure chamber in the second rotary mechanism part increases are respectively in sync. Refrigerant at high pressure is first introduced into a first high-pressure chamber of the first rotary mechanism part. Thereafter, this high-pressure refrigerant passes through a communicating passage and then flows by way of the first low-pressure chamber into the second high-pressure chamber while expanding. The after-expansion refrigerant flows out to an outflow port from a second low-pressure chamber of the second rotary mechanism part.

Rotary type expander and fluid machinery

A casing () houses therein an expansion mechanism () and a compression mechanism (). The expansion mechanism () has a rear head () in which a pressure snubbing chamber () is provided. The pressure snubbing chamber () is divided by a piston () into an inflow/outflow chamber () which fluidly communicates with an inflow port () and a back pressure chamber () which fluidly communicates with the inside of the casing (). The piston () is displaced in response to suction pressure variation whereby the volume of the inflow/outflow chamber () varies. This enables the inflow/outflow chamber () to directly perform supply of refrigerant to or suction of refrigerant from the inflow port () which is a source of pressure variation, thereby making it possible to effectively inhibit suction pressure variation.

Positive displacement expander

A reed valve and a valve retainer for the reed valve are provided at a discharge port of a compression mechanism that compresses fluid. The valve retainer has a polymer actuator at an end part of a valve fixing part for fixing the reed valve. The polymer actuator expands or contracts in length to change a fixed length of the reed valve, thereby changing a rigidity of the reed valve. This attains appropriate control of responsiveness of the reed valve according to the volume.

Compressor

A positive displacement expander includes a volume change mechanism () for changing the volume of a first fluid chamber () of an expansion mechanism (). The expansion mechanism () includes a first rotary mechanism () and a second rotary mechanism () each having a cylinder () containing a rotor (). The first fluid chamber () of the first rotary mechanism () and a second fluid chamber () of the second rotary mechanism () are in fluid communication with each other to form an actuation chamber (). Meanwhile, the first fluid chamber () of the first rotary mechanism () is smaller than the second fluid chamber () of the second rotary mechanism (). The volume change mechanism () includes an auxiliary chamber () fluidly communicating with the first fluid chamber () and an auxiliary piston () for changing the volume of the auxiliary chamber (). The auxiliary chamber () is in fluid communication with the first fluid chamber () of the first rotary mechanism ().

Expander

A first and a second expansion and compression machine () having different volume ratios (Vc/Ve) are connected in parallel to a refrigerant circuit () of a refrigeration apparatus. Expanders () of the expansion and compression machines () are connected in parallel. Compressors () of the expansion and compression machines () are also connected in parallel. Upon variation in the operating condition of the refrigeration apparatus, the ratio of rotation speed between the expansion and compression machines () is controlled by a controller (). This, as a result, allows the refrigeration apparatus to operate at a COP close to an ideal condition.

Refrigeration apparatus

An outdoor heat exchanger (), an indoor heat exchanger (), a compression/expansion unit (), and other circuit components are connected in a refrigerant circuit (). The compression/expansion unit () includes a compression mechanism (), an electric motor (), and an expansion mechanism (). In addition, the refrigerant circuit () has an injection pipeline (). When an injection valve () is opened, a portion of high pressure refrigerant after heat dissipation flows into the injection pipeline () and is introduced into an expansion chamber () of the expansion mechanism () in the process of expansion. In the expansion mechanism (), power is recovered from both high pressure refrigerant introduced into the expansion chamber () from an inflow port () and high pressure refrigerant introduced into the expansion chamber () from the injection pipeline ().

Refrigeration apparatus with expander control for improved coefficient of performance

Two rotary mechanism parts () are provided in a rotary expander (). The first rotary mechanism part () is smaller in displacement volume than the second rotary mechanism part (). A first low-pressure chamber () of the first rotary mechanism part () and a second high-pressure chamber () of the second rotary mechanism part () are fluidly connected together by a communicating passageway (), thereby forming a single expansion chamber (). High-pressure refrigerant introduced into the first rotary mechanism part () expands in the expansion chamber (). An injection passageway () is fluidly connected to the communicating passageway (). When an motor-operated valve () is placed in the open state, high-pressure refrigerant is introduced into the expansion chamber () also from the injection passageway (). This makes it possible to inhibit the drop in power recovery efficiency, even in the condition that causes the actual expansion ratio to fall below the design expansion ratio.

Rotary expander

In a compression/expansion unit () serving as a fluid machine, both a compression mechanism () and an expansion mechanism () are housed in a single casing (). An oil supply passageway () is formed in a shaft () by which the compression mechanism () and the expansion mechanism () are coupled together. Refrigeration oil accumulated in the bottom of the casing () is drawn up into the oil supply passageway () and is supplied to the compression mechanism () and to the expansion mechanism (). Surplus refrigeration oil, which is supplied to neither of the compression and expansion mechanisms () and (), is discharged out of the terminating end of the oil supply passageway () which opens at the upper end of the shaft (). Thereafter, the surplus refrigeration oil flows into an oil return pipe () from a lead-out hole () and is returned back towards a second space (). This reduces the amount of heat input to the fluid flowing through the expansion mechanism from the surplus refrigeration oil which has not been utilized to lubricate the compression and expansion mechanisms.

Fluid machine having reduced heat input to fluid

A refrigerant circuit () of a refrigeration apparatus is filled up with carbon dioxide as a refrigerant. In the refrigerant circuit (), a first compressor () and a second compressor () are arranged in parallel. The first compressor () is connected to both an expander () and a first electric motor (), and is driven by both of the expander () and the first electric motor (). On the other hand, the second compressor () is connected only to a second electric motor (), and is driven by the second electric motor (). In addition, the refrigerant circuit () is provided with a bypass line () which bypasses the expander (). The bypass line () is provided with a bypass valve (). And, the capacity of the second compressor () and the valve opening of the bypass valve () are regulated so that the COP of the refrigeration apparatus is improved after enabling the refrigeration apparatus to operate properly in any operation conditions.

Disclosed is a displacement type expansion machine. In the displacement type expansion machine, a communicating passage () for allowing fluid communication between an expansion-process intermediate position and an outflow position in an expansion chamber () is provided thereby to allow the fluid at the outflow side to return to the expansion chamber (). Such arrangement prevents the pressure of the expansion chamber () from being lowered to an excessive extent in predetermined operating conditions, thereby avoiding the drop in power recovery efficiency.

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Osaka, Japan

Katsumi Sakitani