US5179841A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heat reclamation from and adjustment of defrost cycle
Assignee: Carrier Corp
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Filing: 1991-03-22
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Granted: 1993-01-19
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Expires: 2011-03-22
Abstract
Abstract A adjustable defrost cycle for a heat pump system which ensures that the outdoor coil is maintained free of frost by adjusting a defrost initiation reference level for the initiation of the next subsequent defrost cycle depending upon the time period of the previous defrost cycle.
Inventors
- 👤 Thomas R. Phillips
- 👤 Thomas L. Dewolf
- 👤 Ronald W. Bench
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 08:38
CPC Classifications
F; F25; F25D; F25D21/00; F25D21/002; F25D21/006
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
133 words
A method of adjusting a defrost region curve for determining the initiation of a next subsequent defrost cycle for removing accumulated frost from an outdoor heat exchanger coil including an outdoor fan forming a portion of a refrigerant heat pump system comprising the steps of: initiating a defrost cycle upon comparing the comparison between outdoor ambient temperature and outdoor heat exchanger coil refrigerant temperature with a defrost initiation reference level curve: terminating said defrost cycle; determining the length of time of said defrost cycle; adjusting the defrost initiation reference level curve for the initiation of the next subsequent defrost cycle when said defrost cycle is outside a predetermined time period; and operating a heat reclaim cycle, with the outdoor fan deenergized until the outdoor heat exchanger coil refrigerant temperature reaches a predetermined temperature.
Claim 2
Dependent Claim
67 words
A method as setforth in claim 1 wherein the step of initiating a defrost cycle is calculated by solving the temperature equation for the defrost initiation reference level curve: T c =4/5 T o +Y, where T c is the outdoor heat exchanger coil refrigerant temperature, T o is the outdoor ambient temperature and Y is an ordinate intercept of the outdoor heat exchanger coil refrigerant temperature.
Claim 3
Dependent Claim
68 words
A method as setforth in claim 2 wherein the step of adjusting said defrost initiation reference level curve includes adjusting the ordinate intercept (Y) upwardly by 1.5° C. when said length of time of said defrost cycle is greater than nine minutes and adjusting the ordinate intercept downwardly by 0.5° C. when said length of time of said defrost cycle is less than or equal to five minutes.
Claim 4
Dependent Claim
25 words
A method as setforth in claim 3 wherein the predetermined temperature for operating the heat reclaim cycle is less than or equal to 5.5° C.
Claim 5
Independent Claim
241 words
A method of adjusting the length of time of a next subsequent defrost cycle of removing accumulated frost from an outdoor heat exchanger coil including an outdoor fan forming a portion of a refrigerant heat pump system comprising the steps of: initiating a defrost cycle upon comparing the comparison between outdoor ambient temperature and outdoor heat exchanger coil refrigerant temperature with a defrost initiation reference level, wherein the defrost initiation reference level is calculated by solving the temperature equation: T c =4/5 T o +Y, where T c is the outdoor heat exchanger coil refrigerant temperature, T o is the outdoor ambient temperature and Y is an ordinate intercept of the outdoor heat exchanger coil refrigerant temperature; terminating the defrost cycle; determining the length of time of the defrost cycle; adjusting the defrost initiation reference level for the initiation of the next subsequent defrost cycle when said defrost cycle is outside a predetermined time period, wherein the adjustment of the defrost initiation reference level includes adjusting the ordinate intercept (Y) upwardly by 1.5° C. when said length of time of the defrost cycle is greater than nine minutes and adjusting the ordinate intercept downwardly by 0.5° C. when said length of time of the defrost cycle is less than or equal to five minutes; and operating a heat reclaim cycle with the outdoor fan deenergized until the outdoor heat exchanger coil refrigerant temperature is less than or equal to 5.5° C.
Claim 6
Dependent Claim
26 words
A method as setforth in claim 5 further including the step of energizing said outdoor fan and initiating normal heat mode upon reaching the predetermined temperature.
References Cited (Backward Citations)
US4400949A
Cited
US4916912A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-01-19 | 1996-07-20 | 1997-01-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-01-19 | 2000-07-20 | 2001-01-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-01-19 | 2004-07-20 | 2005-01-19 | $7700.00 | Window Closed / Lapsed |