Patent US3745778A successfully refreshed from Google Patents.
US3745778A
Expired / Lapsed
US
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Method and system for controlling air temperature in an air conditioned zone
Assignee: Robertshaw US Holding Corp
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Filing: 1970-11-09
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Granted: 1973-07-17
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Expires: 1990-11-09
Abstract
Abstract An air conditioning system for air circulating through an air conditioned zone is disclosed. A control system is provided which maintains a predetermined temperature in the zone by operating air heating and air chilling units of the system in either an onoff or a modulating mode. The system responds to the temperature of zone air and air flowing into the zone. Two air cooling units are disclosed, the first one of which can be modulated in its cooling effect and a second unit, having a constant capacity, is operated only if the cooling load exceeds the capacity of the modulatable unit. When the cooling load is less than the full capacity of both units, the first unit is modulated while the second unit operates at capacity. The air heating units are operated in stages. The sensed zone air temperature is primarily responsible for initiating cycles of the heating stages while the sensed duct air temperatures terminate operation of the heating stages. The heating stages have low thermal inertias so that they can be rapidly cycled.
Inventors
- 👤 R Attridge
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 21:27
CPC Classifications
F; F24; F24F; F24F11/00; F24F11/30; F24F11/32; G; G05; G05D; G05D23/00; G05D23/19; G05D23/1906; G05D23/1912; G05D23/1919; G05D23/1921; G05D23/20; G05D23/24
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
321 words
A method of controlling air temperature in an air conditioned zone comprising: a. providing at least first and second refrigeration units; b. directing air across air cooling heat exchangers of said units and into said zone through a zone air inlet; c. producing a zone air temperature signal which varies in magnitude relative to a reference level in accordance with fluctuations in sensed air temperature in said zone; d. producing an air temperature signal varying in magnitude relative to said reference level in accordance with fluctuations in sensed temperature of air supplied to said zone; e. combining said zone and supply air temperature signals to produce a composite cooling temperature signal varying in magnitude relative to said reference level; f. initiating operation of said first refrigeration unit in response to production of a first composite cooling temperature signal having a predetermined magnitude relative to said reference level and terminating operation of said first unit in response to production of a second composite temperature signal having a second predetermined magnitude less than the magnitude of said first signal; g. initiating operation of said second refrigeration unit in response to a third composite temperature signal level having a greateR magnitude than said first signal level and terminating operation of said second unit at a fourth composite temperature signal level having a greater magnitude than said second composite signal level and a lesser magnitude than said first composite signal level; and, h. modulating the cooling capacity of said first unit between full capacity and a lesser capacity in accordance with composite temperature signals ranging between fifth and sixth levels, said range of modulating composite signals between said fifth and sixth levels being of lesser magnitude than said first signal level and greater magnitude than said fourth signal level whereby the capacity of said first refrigeration unit is fully modulatable when said first unit is operating and when said first and second units are operating.
Claim 2
Independent Claim
321 words
A method of controlling air temperature in an air conditioned zone comprising: a. providing at least first and second refrigeration units; b. directing air across air cooling heat exchangers of said units and into said zone through a zone air inlet; c. producing a zone air temperature signal which varies in magnitude relative to a reference level in accordance with fluctuations in sensed air temperature in said zone; d. producing an air temperature signal varying in magnitude relative to said reference level in accordance with fluctuations in sensed temperature of air supplied to said zone; e. combining said zone and supply air temperature signals to produce a composite cooling temperature signal varying in magnitude relative to said reference level; f. initiating operation of said first refrigeration unit in response to production of a first composite cooling temperature signal having a predetermined magnitude relative to said reference level and terminating operation of said first unit in response to production of a second composite temperature signal having a second predetermined magnitude less than the magnitude of said first signal; g. initiating operation of said second refrigeration unit in response to a third composite temperature signal level having a greateR magnitude than said first signal level and terminating operation of said second unit at a fourth composite temperature signal level having a greater magnitude than said second composite signal level and a lesser magnitude than said first composite signal level; and, h. modulating the cooling capacity of said first unit between full capacity and a lesser capacity in accordance with composite temperature signals ranging between fifth and sixth levels, said range of modulating composite signals between said fifth and sixth levels being of lesser magnitude than said first signal level and greater magnitude than said fourth signal level whereby the capacity of said first refrigeration unit is fully modulatable when said first unit is operating and when said first and second units are operating.
Claim 3
Dependent Claim
22 words
A method as claimed in claim 1 wherein modulating said cooling capacity includes variably restricting refrigerant flow in said first refrigeration unit.
Claim 4
Dependent Claim
40 words
A method as claimed in claim 1 and further including providing ventilating air to said zone in proportion to changes in composite temperature signals between said reference level and a seventh composite signal level less than said second signal level.
Claim 5
Dependent Claim
38 words
A method as claimed in claim 1 wherein said first refrigeration unit is initially operated at full capacity and is modulated from full capacity as said composite signal level is reduced from said fifth toward said sixth level.
Claim 6
Dependent Claim
71 words
A method as claimed in claim 1 wherein said zone supply air temperature signal and said zone temperature signal are algebraically combined to produce said composite signal, and wherein a predetermined change in zone supply air temperature produces a small change in magnitude of said supply air temperature signal as compared to the change in magnitude of said zone temperature signal produced by the zone air temperature undergoing said predetermined change.
Claim 7
Dependent Claim
42 words
A method as claimed in claim 5 wherein operation of said refrigeration units is initiated primarily in response to zone air temperature signal levels and the cooling capacity of said units is modulated primarily according to zone supply air temperature signal levels.
Claim 8
Dependent Claim
40 words
A method as claimed in claim 5 wherein the authority ratio of said zone air temperature signal to said supply air temperature signal is about 20:1 when said zone air temperature and a zone set point temperature are the same.
Claim 9
Dependent Claim
346 words
In a system for cooling air in a zone having at least first and second refrigeration units and capacity control means for variably controlling the cooling capacity of at least said first refrigeration unit: a. first air temperature sensing means exposed to air in said zone; b. second air temperature sensing means exposed to air supplied to said zone; c. first and second signal responsive means for operating said first and second signal refrigeration units, respectively; d. a third signal responsive means for operating said capacity control means; e. signal generating means having an input connected to said first and second air temperature sensing means and an output connected to said first, second and third signal responsive means; f. said first and second air temperature sensing means producing air temperature responsive signals and said signal generating means responding to air temperature signals from said first and second air temperature sensing means to produce a temperature responsive output signal applied to said signal responsive means; g. said first signal responsive means effective to initiate operation of said first refrigeration unit at a first output signal level and to terminate operation of said first unit at a second output signal level of lesser magnitude than said first signal level; h. said third signal responsive means operating said capacity control means to modulate the capacity of said first refrigeration unit between third and fourth output signal levels of lesser magnitude than said first output signal level and greatEr magnitude than said second output signal level; and, i. said second signal responsive means effective to initiate operation of said second unit at a fifth output signal level having a greater magnitude than said first output signal level and terminating operation of said second unit at a sixth output signal level of lesser magnitude than said third and fourth output signal levels; j. said third signal responsive means modulating the capacity of said first unit between said third and fourth output signal levels during operation of said first unit alone and when both of said first and second units are operating.
Claim 10
Dependent Claim
346 words
In a system for cooling air in a zone having at least first and second refrigeration units and capacity control means for variably controlling the cooling capacity of at least said first refrigeration unit: a. first air temperature sensing means exposed to air in said zone; b. second air temperature sensing means exposed to air supplied to said zone; c. first and second signal responsive means for operating said first and second signal refrigeration units, respectively; d. a third signal responsive means for operating said capacity control means; e. signal generating means having an input connected to said first and second air temperature sensing means and an output connected to said first, second and third signal responsive means; f. said first and second air temperature sensing means producing air temperature responsive signals and said signal generating means responding to air temperature signals from said first and second air temperature sensing means to produce a temperature responsive output signal applied to said signal responsive means; g. said first signal responsive means effective to initiate operation of said first refrigeration unit at a first output signal level and to terminate operation of said first unit at a second output signal level of lesser magnitude than said first signal level; h. said third signal responsive means operating said capacity control means to modulate the capacity of said first refrigeration unit between third and fourth output signal levels of lesser magnitude than said first output signal level and greatEr magnitude than said second output signal level; and, i. said second signal responsive means effective to initiate operation of said second unit at a fifth output signal level having a greater magnitude than said first output signal level and terminating operation of said second unit at a sixth output signal level of lesser magnitude than said third and fourth output signal levels; j. said third signal responsive means modulating the capacity of said first unit between said third and fourth output signal levels during operation of said first unit alone and when both of said first and second units are operating.
Claim 11
Dependent Claim
69 words
A system as claimed in claim 8 further including summing circuitry connecting said first and second air temperature sensing means to said signal generating means, said summing circuitry applying the algebraic sum of temperature signals from said first and second air temperature sensing means to said signal generating means, said second air temperature sensing means having a relatively small authority as compared to said first air temperature sensing means.
Claim 12
Dependent Claim
88 words
A system as claimed in claim 8 wherein said signal generating means produces a variable voltage output signal, said first and second signal responsive means comprise voltage responsive bistable electronic switches for energizing and deenergizing respective electrically powered refrigeration units, and said capacity control means comprises a refrigerant flow controlling unit associated with said first refrigeration unit for variably controlling the flow of refrigerant in said first refrigeration unit to thereby control the cooling capacity of said unit in response to operation of said third signal responsive means.
Claim 13
Dependent Claim
78 words
A system as claimed in claim 10 and further including zone set point adjusting circuitry for establishing an adjustable zone set point temperature, said zone set point adjusting circuitry comprising an adjustable impedance element for shifting the level of said air temperature responsive signals relative to a reference voltage to thereby change the zone set point temperature, and wherein the levels of said first through sixth output signals vary from said reference voltage level in one sense direction.
Claim 14
Independent Claim
304 words
A method of controlling air temperature in an air conditioned zone comprising: a. providing first and second refrigeration units; b. directing air across air cooling heat exchangers of said units and into said zone; c. producing an electric air temperature responsive signal which varies in magnitude relative to a reference level in accordance with fluctuations in sensed air temperature, said air temperature responsive signal increasing in magnitude relative to the reference level in response to increases in sensed air temperature and decreasing in magnitude relative to the reference level in response to decreases in sensed air temperature; d. initiating operation of said first refrigeration unit in response to production of a first air temperature signal having a first magnitude relative to said reference level and terminating operation of said first unit in response to production of a second air temperature signal having a second magnitude less than the magnitude of said first signal; e. initiating operation of said second refrigeration unit in response to a third air temperature signal level having a greater magnitude than said first air temperature signal level and terminating operation of said second unit at a fourth air temperature signal level having a greater magnitude than said second air temperature signal level and a lesser magnitude than said first air temperature signal level; and, f. modulating the cooling capacity of said first unit between full capacity and a lesser capacity in accordance with air temperature signals ranging between fifth and sixth levels, said range of modulating signals between said fifth and sixth levels being of lesser magnitude than said first air temperature signal level and greater magnitude than said Fourth air temperature signal level whereby the capacity of said first refrigeration unit is fully modulatable when said first unit is operating and when said first and second units are operating.
Claim 15
Independent Claim
304 words
A method of controlling air temperature in an air conditioned zone comprising: a. providing first and second refrigeration units; b. directing air across air cooling heat exchangers of said units and into said zone; c. producing an electric air temperature responsive signal which varies in magnitude relative to a reference level in accordance with fluctuations in sensed air temperature, said air temperature responsive signal increasing in magnitude relative to the reference level in response to increases in sensed air temperature and decreasing in magnitude relative to the reference level in response to decreases in sensed air temperature; d. initiating operation of said first refrigeration unit in response to production of a first air temperature signal having a first magnitude relative to said reference level and terminating operation of said first unit in response to production of a second air temperature signal having a second magnitude less than the magnitude of said first signal; e. initiating operation of said second refrigeration unit in response to a third air temperature signal level having a greater magnitude than said first air temperature signal level and terminating operation of said second unit at a fourth air temperature signal level having a greater magnitude than said second air temperature signal level and a lesser magnitude than said first air temperature signal level; and, f. modulating the cooling capacity of said first unit between full capacity and a lesser capacity in accordance with air temperature signals ranging between fifth and sixth levels, said range of modulating signals between said fifth and sixth levels being of lesser magnitude than said first air temperature signal level and greater magnitude than said Fourth air temperature signal level whereby the capacity of said first refrigeration unit is fully modulatable when said first unit is operating and when said first and second units are operating.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-16 | 1977-01-15 | 1977-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-16 | 1981-01-15 | 1981-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-16 | 1985-01-15 | 1985-07-17 | $7700.00 | Window Closed / Lapsed |