Refrigeration cycle apparatus with an expander to recover power from refrigerant

Patent metadata

Field	Value
Publication number	US-9353975-B2
Application number	US-200913394970-A
Country	US
Kind code	B2
Filing date	Sep 24, 2009
Priority date	Sep 24, 2009
Publication date	May 31, 2016
Grant date	May 31, 2016

Abstract

A refrigeration cycle apparatus includes a refrigeration cycle formed by a first compressor, a radiator, an expander that expands a refrigerant that has passed through the radiator, and an evaporator. A bypass piping has one end connected to a discharge piping of the expander and the other end connected to a suction piping of the first compressor. A pressure sensor and a temperature sensor detect the suction pressure and suction temperature of the expander as physical quantities of the refrigerant to be sucked into the expander. A bypass valve controls the flow rate of the refrigerant. A control device determines the appropriate discharge pressure of the expander on the basis of the suction pressure and suction temperature of the expander, and opens the bypass valve when the pressure at which the expander discharges the refrigerant is higher than the determined appropriate discharge pressure.

First claim

The invention claimed is:

1. A refrigeration cycle apparatus, comprising:
a refrigeration cycle formed by sequentially connecting with pipes, a first compressor that compresses a refrigerant, a second compressor that further compresses the refrigerant compressed by the first compressor, a radiator that rejects the heat of the refrigerant compressed by the second compressor, an expander that is connected to a drive shaft of one of the first compressor and the second compressor, and that expands the refrigerant that has passed through the radiator, recovers power from the refrigerant and drives the drive shafts with the recovered power, and an evaporator that evaporates the refrigerant expanded by the expander, and an accumulator;
a first bypass piping having one end connected to a discharge piping of the expander and the other end connected to a piping between an inlet piping of the accumulator and the discharge of the evaporator;
a physical quantity detecting sensor that detects a physical quantity of the refrigerant to be sucked into the expander;
a first bypass valve provided in the first bypass piping to control the flow rate of the refrigerant; and
control means that controls an opening degree of the first bypass valve,
wherein the control means determines an appropriate discharge pressure of the expander on the basis of the physical quantity detected by the physical quantity detecting sensor and opens the first bypass valve when a pressure at which the expander discharges the refrigerant is higher than the determined appropriate discharge pressure.

2. The refrigeration cycle apparatus of claim 1 ,
wherein the control means opens the first bypass valve before starting the first compressor.

3. The refrigeration cycle apparatus of claim 1 ,
wherein the discharge piping of the expander is provided with a check valve that arranges the flow of the refrigerant in one direction.

4. The refrigeration cycle apparatus of claim 1 , further comprising:
a second bypass piping that bypasses a portion of the refrigerant that has passed through the radiator to an inlet side of the evaporator being provided between the radiator and the evaporator, the second bypass piping including a second bypass valve; and
a refrigerant heat exchanger exchanging heat between the refrigerant directed towards the evaporator via the second bypass valve and the refrigerant directed towards the first compressor via the first bypass valve.

5. The refrigeration cycle apparatus of claim 1 , further comprising:
a third bypass piping having one end connected to a discharge piping of the first compressor and the other end connected to the suction piping of the first compressor,
wherein the third bypass piping is provided with a third bypass valve that adjusts the flow rate of the refrigerant.

6. The refrigeration cycle apparatus of claim 1 , the radiator further comprising;
an intercooler that cools the refrigerant discharged from either the first compressor or the second compressor before the refrigerant is sucked into the other of the first compressor or the second compressor; and
a main radiator that cools the refrigerant discharged from the other of the first compressor and the second compressor.

7. The refrigeration cycle apparatus of claim 1 ,
wherein the refrigerant is carbon dioxide.

Assignees

• Takayama Keisuke
• Shimazu yusuke
• Kakuda Masayuki
• Nagata Hideaki
• Hatomura Takeshi
• Mitsubishi Electric Corp

Inventors

• Takayama Keisuke
• Shimazu yusuke
• Kakuda Masayuki
• Nagata Hideaki
• Hatomura Takeshi

Classifications

• F25B2600/2501

  Bypass valves · CPC title

• F25B2400/14

  Power generation using energy from the expansion of the refrigerant · CPC title

• F25B2313/02742

  using two four-way valves · CPC title

• F25B13/00

  Compression machines, plants or systems, with reversible cycle (defrosting cycles F25B47/02) · CPC title

• F25B2309/061

  with cycle highest pressure above the supercritical pressure · CPC title