US6968708B2
Expired / Lapsed
US
⏱️ 0.0 years remaining
Refrigeration system having variable speed fan
Assignee: Carrier Corp
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Filing: 2003-06-23
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Granted: 2005-11-29
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Expires: 2023-06-23
Abstract
Abstract A transcritical refrigeration system includes a compressor, a gas cooler, an expansion device, and an evaporator. Refrigerant is circulated though the closed circuit system. Preferably, carbon dioxide is used as the refrigerant. A fan moves outdoor air that exchanges heat with the refrigerant across the evaporator. The speed of the fan is regulated to regulate the evaporator pressure and to adapt the evaporator to different environmental conditions to achieve the optimal coefficient of performance. During high ambient conditions, the fan speed is decreased, decreasing the refrigerant mass flowrate in the system. The energy exchange per unit mass of the refrigerant in the gas cooler increases and the work of the fan decreases, increasing the coefficient of performance of the system. During low ambient conditions, the mass flowrate of the system is low and there is more heat transfer thermal resistance on the refrigerant side at the evaporator. The speed of the fan is lowered to decrease the work of the fan. Therefore, the coefficient of performance increases.
Inventors
- 👤 Sivakumar Gopalnarayanan
- 👤 Yu Chen
- 👤 Tobias Sienel
- 👤 Lili Zhang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 01:38
CPC Classifications
F; F25; F25B; F25B9/00; F25B9/002; F25B9/008; F25B1/00; F25B49/00; F25B2309/00; F25B2309/06; F25B2309/061; F25B2339/00; F25B2339/04; F25B2339/047; F25B2500/00; F25B2500/31; F25B2600/00; F25B2600/11; F25B2600/112; F25B2600/17; F25B2700/00; F25B2700/21; F25B2700/2106; Y; Y02; Y02B; Y02B30/00; Y02B30/70
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
160 words
A transcritical refrigeration system comprising: a compression device to compress a refrigerant to a high pressure; a heat rejecting heat exchanger for cooling said refrigerant; an expansion device for reducing said refrigerant to a low pressure; a heat accepting heat exchanger for evaporating said refrigerant, and an airflow exchanges heat with said refrigerant in said heat accepting heat exchanger; a variable speed device that moves said airflow at a variable airflow speed, and said variable speed device moves at a device speed; a drive that controls said device speed of said variable speed device; and a temperature sensor that senses an airflow temperature of said airflow, and said drive adjusts said variable speed device and said variable airflow speed of said airflow based on said airflow temperature, wherein said airflow is outdoor air and said variable speed device is deactivated prior to activating said compression device when said temperature sensor detects that said airflow temperature is above a threshold temperature.
Claim 2
Dependent Claim
160 words
A transcritical refrigeration system comprising: a compression device to compress a refrigerant to a high pressure; a heat rejecting heat exchanger for cooling said refrigerant; an expansion device for reducing said refrigerant to a low pressure; a heat accepting heat exchanger for evaporating said refrigerant, and an airflow exchanges heat with said refrigerant in said heat accepting heat exchanger; a variable speed device that moves said airflow at a variable airflow speed, and said variable speed device moves at a device speed; a drive that controls said device speed of said variable speed device; and a temperature sensor that senses an airflow temperature of said airflow, and said drive adjusts said variable speed device and said variable airflow speed of said airflow based on said airflow temperature, wherein said airflow is outdoor air and said variable speed device is deactivated prior to activating said compression device when said temperature sensor detects that said airflow temperature is above a threshold temperature.
Claim 3
Dependent Claim
162 words
A transcritical refrigeration system comprising: a compression device to compress a refrigerant to a high pressure; a heat rejecting heat exchanger for cooling said refrigerant; an expansion device for reducing said refrigerant to a low pressure; a heat accepting heat exchanger for evaporating said refrigerant, and an airflow exchanges heat with said refrigerant in said heat accepting heat exchanger; a variable speed device that moves said airflow at a variable airflow speed, and said variable speed device moves at a device speed; a drive that controls said device speed of said variable speed device; and a temperature sensor that senses an airflow temperature of said airflow, and said drive adjusts said variable speed device and said variable airflow speed of said airflow based on said airflow temperature, wherein said drive decreases said device speed of said variable speed device to decrease said variable airflow speed of said airflow when said temperature sensor detects that said airflow temperature is above a threshold temperature.
Claim 4
Dependent Claim
162 words
A transcritical refrigeration system comprising: a compression device to compress a refrigerant to a high pressure; a heat rejecting heat exchanger for cooling said refrigerant; an expansion device for reducing said refrigerant to a low pressure; a heat accepting heat exchanger for evaporating said refrigerant, and an airflow exchanges heat with said refrigerant in said heat accepting heat exchanger; a variable speed device that moves said airflow at a variable airflow speed, and said variable speed device moves at a device speed; a drive that controls said device speed of said variable speed device; and a temperature sensor that senses an airflow temperature of said airflow, and said drive adjusts said variable speed device and said variable airflow speed of said airflow based on said airflow temperature, wherein said drive decreases said device speed of said variable speed device to decrease said variable airflow speed of said airflow when said temperature sensor detects that said airflow temperature is above a threshold temperature.
Claim 5
Dependent Claim
13 words
The system as recited in claim 2 wherein said refrigerant is carbon dioxide.
Claim 6
Dependent Claim
15 words
The system as recited in claim 2 wherein said variable speed device is a fan.
Claim 7
Dependent Claim
14 words
The system as recited in claim 2 wherein said threshold temperature is 80° F.
Claim 8
Dependent Claim
14 words
The system as recited in claim 1 wherein said threshold temperature is 100° F.
Claim 9
Dependent Claim
55 words
The system as recited in claim 1 further including a pressure sensor that senses a pressure of said refrigerant at a suction of said compression device, wherein said variable speed device is activated when said pressure sensor senses that said pressure of said refrigerant at said suction of said compression device exceeds a threshold pressure.
Claim 10
Dependent Claim
166 words
A transcritical refrigeration system comprising: a compression device to compress a refrigerant to a high pressure; a heat rejecting heat exchanger for cooling said refrigerant; an expansion device for reducing said refrigerant to a low pressure; a heat accepting heat exchanger for evaporating said refrigerant, and an airflow exchanges heat with said refrigerant in said heat accepting heat exchanger; a variable speed device that moves said airflow at a variable airflow speed, and said variable speed device moves at a device steep; a drive that controls said device speed of said variable speed device; and a temperature sensor that senses an airflow temperature of said airflow, and said drive adjusts said variable speed device and said variable airflow speed of said airflow based on said airflow temperature, wherein said airflow is outdoor air and said drive decreases said device speed of said variable speed device said variable airflow speed of said airflow when said temperature sensor detects that said airflow temperature is below a threshold temperature.
Claim 11
Dependent Claim
166 words
A transcritical refrigeration system comprising: a compression device to compress a refrigerant to a high pressure; a heat rejecting heat exchanger for cooling said refrigerant; an expansion device for reducing said refrigerant to a low pressure; a heat accepting heat exchanger for evaporating said refrigerant, and an airflow exchanges heat with said refrigerant in said heat accepting heat exchanger; a variable speed device that moves said airflow at a variable airflow speed, and said variable speed device moves at a device steep; a drive that controls said device speed of said variable speed device; and a temperature sensor that senses an airflow temperature of said airflow, and said drive adjusts said variable speed device and said variable airflow speed of said airflow based on said airflow temperature, wherein said airflow is outdoor air and said drive decreases said device speed of said variable speed device said variable airflow speed of said airflow when said temperature sensor detects that said airflow temperature is below a threshold temperature.
Claim 12
Dependent Claim
14 words
The system as recited in claim 8 wherein said threshold temperature is 20° F.
Claim 13
Dependent Claim
23 words
The system as recited in claim 2 wherein said device speed of said variable speed devices is varied to optimize a system performance.
Claim 14
Independent Claim
82 words
A method of regulating a coefficient of performance of a transcritical refrigeration system comprising the steps of: compressing a refrigerant to a high pressure; cooling the refrigerant; expanding the refrigerant to a low pressure; evaporating the refrigerant by exchanging heat between the refrigerant and an airflow having a variable airflow speed; sensing an airflow temperature of the airflow; and decreasing the variable airflow speed of the airflow when the airflow temperature is above a threshold value, wherein the airflow is outdoor air.
Claim 15
Independent Claim
82 words
A method of regulating a coefficient of performance of a transcritical refrigeration system comprising the steps of: compressing a refrigerant to a high pressure; cooling the refrigerant; expanding the refrigerant to a low pressure; evaporating the refrigerant by exchanging heat between the refrigerant and an airflow having a variable airflow speed; sensing an airflow temperature of the airflow; and decreasing the variable airflow speed of the airflow when the airflow temperature is above a threshold value, wherein the airflow is outdoor air.
Claim 16
Dependent Claim
22 words
The system as recited in claim 2 further including an accumulator positioned between said heat accepting heat exchanger and said compression device.
References Cited (Backward Citations)
US3410105A
Cited
US5086626A
Cited
US5245836A
Cited
US5255529A
Cited
US5797276A
Cited
US5568732A
Cited
US5490394A
Cited
US5613369A
Cited
US5694783A
Cited
US5657638A
Cited
US5782101A
Cited
US6073457A
Cited
EP0924480A2
Cited
US6560980B2
Cited
US6415617B1
Cited
US6397610B1
Cited
WO2003036184A1
Cited
WO2003069236A1
Cited
US6694763B2
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2008-11-28 | 2009-05-30 | 2009-11-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2012-11-28 | 2013-05-30 | 2013-11-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2016-11-28 | 2017-05-30 | 2017-11-29 | $7700.00 | Window Closed / Lapsed |