# US 2014/0150489 A1 · Startup Logic For Refrigeration System

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- Number: US 2014/0150489 A1
- Document ID: US20140150489A1
- Status: Published application
- Kind: A1
- Application number: 14/234,675
- Filed: 2012-07-25
- Published: 2014-06-05
- Earliest claimed: 2011-07-26
- Assignees: Carrier Corporation
- Inventors: Mingfei Gan; KeonWoo Lee; Hans-Joachim Huff; Aryn Shapiro; Lucy Yi Liu; Gilbert B. Hofsdal; Jian Sun
- Web page: https://patentgrep.com/patent/US20140150489A1

## CPC

- F25D 17/06: by forced circulation
- F25B 1/10: with multi-stage compression (with cascade operation F25B7/00)
- F25B 49/027: {Condenser control arrangements}
- F25B 41/39: Dispositions with two or more expansion means arranged in series, i.e. multi-stage expansion, on a refrigerant line leading to the same evaporator
- F25B 2400/01: Heaters
- F25B 2400/072: Intercoolers therefor
- F25B 2400/13: Economisers
- F25B 2400/23: Separators
- F25B 2500/26: characterised by the startup of the refrigeration cycle
- F25B 2500/31: Low ambient temperatures
- F25B 2600/022: for multi-stage operation
- F25B 2600/0253: with variable speed
- F25B 2600/0261: external to the compressor
- F25B 2600/111: of condenser fans
- F25B 2600/112: of evaporator fans
- F25B 2600/2509: Economiser valves
- F25B 2600/2513: Expansion valves
- F25B 2700/195: of the condenser
- F25B 2700/2102: at the outlet of the gas cooler
- F25B 2700/21151: at the suction side of the compressor
- F25B 2700/21152: at the discharge side of the compressor
- F25B 2700/21171: of the fluid cooled by the evaporator
- Y02B 30/70: Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating
- F25D: REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR (refrigerated showcases A47F3/04; thermally-insulated vessels for domestic use A47J41/00; refrigerated vehicles, see the appropriate subclasses of classes B60 - B64; containers with thermal insulation in general B65D81/38; heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants, or materials for the production of heat or cold by chemical reactions other than by combustion C09K5/00; thermally-insulated vessels for liquefied or solidified gases F17C; air-conditioning or air-humidification F24F; refrigeration machines, plants, or systems F25B; cooling of instruments or comparable apparatus without refrigeration G12B)
- F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS

## Abstract

A refrigeration system (10) includes a compressor (20) having a first stage (20a) and a second stage (20b); a heat rejecting heat exchanger (40) having a fan (44) drawing ambient fluid over the heat rejecting heat exchanger, the heat rejecting heat exchanger including an inter-cooler (43) and a gas cooler(41), the intercooler coupled to an outlet of the first stage and the gas cooler coupled to an outlet of the second stage;, an unload valve (93) coupled to an outlet of the intercooler and a suction port of the first stage; a flash tank (70) coupled to an outlet of the gas cooler; a primary expansion device (55) coupled to an outlet of the flash tank; a heat absorbing heat exchanger (50) coupled to an outlet of the primary expansion device, an outlet of the heat absorbing heat exchanger coupled to the suction port of the first stage; and a controller (100) for executing a startup process.

## Claims

### Claim 1

A refrigeration system comprising:
a compressor having a first stage and a second stage;
a heat rejecting heat exchanger having a fan drawing ambient fluid over the heat rejecting heat exchanger, the heat rejecting heat exchanger including an intercooler and a gas cooler, the intercooler coupled to an outlet of the first stage and the gas cooler coupled to an outlet of the second stage;
an unload valve coupled to an outlet of the intercooler and a suction port of the first stage;
a flash tank coupled to an outlet of the gas cooler;
a primary expansion device coupled to an outlet of the flash tank;
a heat absorbing heat exchanger coupled to an outlet of the primary expansion device, an outlet of the heat absorbing heat exchanger coupled to the suction port of the first stage; and
a controller for executing a startup process including at least one of:
controlling the fan speed to reduce refrigerant heat loss in the heat rejecting heat exchanger;
controlling the unload valve to direct refrigerant from the intercooler to the suction port of the first stage; and
controlling the primary expansion device to restrict flow of refrigerant to the heat absorbing heat exchanger.

### Claim 2 (depends on 1)

The refrigeration system of claim 1 wherein:
the startup process includes at least two of:
controlling the fan speed to reduce refrigerant heat loss in the heat rejecting heat exchanger;
controlling the unload valve to direct refrigerant from the intercooler to the suction port of the first stage; and
controlling the primary expansion device to restrict flow of refrigerant to the heat absorbing heat exchanger.

### Claim 3 (depends on 1)

The refrigeration system of claim 1 wherein:
the startup process includes all of:
controlling the fan speed to reduce refrigerant heat loss in the heat rejecting heat exchanger;
controlling the unload valve to direct refrigerant from the intercooler to the suction port of the first stage; and
controlling the primary expansion device to restrict flow of refrigerant to the heat absorbing heat exchanger.

### Claim 4 (depends on 1)

The refrigeration system of claim 1 further comprising:
an economizer valve coupling the flash tank to an inlet of the second stage;

### Claim 5 (depends on 4)

The refrigeration system of claim 4 wherein:
the startup process includes controlling the economizer valve to control flow of refrigerant from the flash tank to the inlet of the second stage.

### Claim 6 (depends on 5)

The refrigeration system of claim 5 wherein:
controlling the economizer valve includes opening the economizer valve.

### Claim 7 (depends on 1)

The refrigeration system of claim 1 further comprising:
a motor for driving the first stage and the second stage;
the startup process including applying direct current to the motor.

### Claim 8 (depends on 1)

The refrigeration system of claim 1 wherein:
controlling the fan speed includes controlling fan speed in response to superheat.

### Claim 9 (depends on 8)

The refrigeration system of claim 8 wherein:
the fan speed is proportional to the superheat.

### Claim 10 (depends on 1)

The refrigeration system of claim 1 wherein:
controlling the unload valve includes opening the unload valve.

### Claim 11 (depends on 1)

The refrigeration system of claim 1 wherein:
controlling the primary expansion device includes controlling primary expansion device in response to superheat.

### Claim 12 (depends on 11)

The refrigeration system of claim 11 wherein:
controlling the primary expansion device incrementally opening the primary expansion device in response to increasing superheat.