EP0104872A2
Expired / Lapsed
EP
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Air conditioning and compressor control system
Assignee: Dunham Bush Inc
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Filing: 1983-09-20
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Granted: —
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Expires: 2003-09-20
Abstract
Abstract A control system progressively increases the capacity levels of a compressor capable of operation at multiple capacity levels in accordance with the sensed return air temperature (RAA, RAB, RAC) within limits permitted by the sensed evaporator coil temperature. Excessive relative humidity (RHS) will turn on the system if it is not already running and raise the capacity level by one step if it is already running. Logic circuitry controls or terminates compressor operation in response to an air conditioning mode signal (A/C MODEl, compressor suction pressure (LDS, PDPS), discharge pressure (HPS1, HPS2), discharge temperature (DTS1, DTS2), evaporator coil temperature (CTD, CTE, CTF), return air temperature (RAA, RAB, RAC) ambient temperature and relative humidity (RHS). In addition, the control system is capable of controlling a return air heating relay (50) as a function of return air temperature either when in a heating mode of operation or when necessary to re-heat chilled and de-humidified return air when in an air conditioning mode operation.
Inventors
- 👤 James P. Somerset
- 👤 David N. Shaw
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 21:51
CPC Classifications
G; G05; G05D; G05D23/00; G05D23/19; G05D23/1906; G05D23/1912; F; F24; F24F; F24F11/00; F24F11/70; F24F11/80; F24F11/86; F24F11/30; F24F11/32; F24F11/38; F24F11/50; F24F11/52; F24F11/62; F24F11/63; F24F11/88; F25; F25B; F25B49/00; F25B49/02; F25B49/022; F24F2110/00; F24F2110/10; F24F2110/20; F24F2140/00
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
226 words
A control system for a compressor in an air conditioning system of the type wherein the compressor receives a working gas through an intake and compresses the working gas, which gas is then passed from a compressor discharge through a condensor and then through an evaporator, and wherein air is drawn in from an area and passed over the evaporator to be cooled, and then returned to the said area, the compressor being of a type operable at a first capacity level in response to a first control signal for providing a first degree of compression to the working gas and at a second capacity level in response to a second control signal for providing a second greater degree of compression to the working gas, characterised in that the control system comprises temperature sensing means (10) for sensing the temperature of the returned air, the temperature sensing means providing a first temperature signal (RAA) when the return air temperature is above a first temperature level to cause the compressor to operate at the first capacity level, and a second temperature signal (RAB) when the return air temperature is above a second temperature level to cause the compressor to operate at the second capacity level, and control means(Fig.5) for providing the first (43) and second (45) control signals in response to the first and second temperature signals.
Claim 2
Dependent Claim
226 words
A control system for a compressor in an air conditioning system of the type wherein the compressor receives a working gas through an intake and compresses the working gas, which gas is then passed from a compressor discharge through a condensor and then through an evaporator, and wherein air is drawn in from an area and passed over the evaporator to be cooled, and then returned to the said area, the compressor being of a type operable at a first capacity level in response to a first control signal for providing a first degree of compression to the working gas and at a second capacity level in response to a second control signal for providing a second greater degree of compression to the working gas, characterised in that the control system comprises temperature sensing means (10) for sensing the temperature of the returned air, the temperature sensing means providing a first temperature signal (RAA) when the return air temperature is above a first temperature level to cause the compressor to operate at the first capacity level, and a second temperature signal (RAB) when the return air temperature is above a second temperature level to cause the compressor to operate at the second capacity level, and control means(Fig.5) for providing the first (43) and second (45) control signals in response to the first and second temperature signals.
Claim 3
Dependent Claim
126 words
A control system according to claim 1 for a compressor which is capable of operating also at a third capacity level in response to a third control signal characterised in that the temperature sensing means provides a third temperature signal (RAC) when the return air temperature exceeds a third temperature higher than the second temperature and the control means provides the third control signal (47) in response to the third temperature signal, the control means generating the second control signal (45) in response to the second temperature signal (RAB) only when the first control signal (43) is being generated, and the control means generating the third control signal (47) in response to the third temperature signal (RAC) only when the control signal (45) is being generated.
Claim 4
Dependent Claim
59 words
A control system according to claim 1 or claim 2 and further comprising evaporator temperature sensing means (12) for providing an evaporator temperature indication representing the temperature of the evaporator means, the control means inhibiting the generation of at least one of the control signals in response to an excessively low temperature detected by the evaporator temperature sensing means.
Claim 5
Dependent Claim
93 words
A control system according to claim 3 wherein the evaporator temperature indication comprises a first evaporator temperature signal (CTD or CTDD) when the evaporator temperature is below a first evaporator temperature and a second evaporator temperature signal (CTE) when the evaporator temperature is below a second temperature higher than the first evaporator temperature, the control means being responsive to the first evaporator temperature signal to inhibit the generation of the first control signal, and being responsive to the second evaporator temperature signal (CTE) for inhibiting the generation of the second control signal (45).
Claim 6
Dependent Claim
71 words
A control system according to claim 4 wherein the evaporator temperature sensing means includes means for delaying the generation of the first evaporator temperature signal (CTDD) for a first period of time after the evaporator temperature falls below the first evaporator temperature and means for delaying the termination of the first evaporator temperature signal (CTDD) for a second period of time after the evaporator temperature rises above the first evaporator temperature.
Claim 7
Dependent Claim
90 words
A control system according to any one of the preceding claims further comprising discharge temperature sensing means (14) for sensing the working gas temperature at the compressor discharge, the control means providing a compressor cooling signal (49) to activate compressor cooling means in response to a compressor discharge temperature exceeding a first predetermined discharge temperature level and the control means disabling the compressor in response to a safety signal (DTS2 or DTS2D) from the discharge temperature sensing means indicating a detected discharge temperature exceeding a second predetermined discharge temperature level.
Claim 8
Dependent Claim
112 words
A control system according to any one of the preceding claims further comprising discharge pressure sensing means (20, 22) for generating a first discharge pressure signal (TLS) when the pressure of the working gas at the compressor discharge exceeds a first predetermined discharge pressure level and a second discharge pressure safety signal (HDS-2) when the discharge pressure of the working gas exceeds a second predetermined discharge pressure higher than the first discharge pressure, the control means being responsive to the first discharge pressure signal for inhibiting the generation of the second control signal and being responsive to the second discharge pressure safety signal for inhibiting the generation of the first control signal.
Claim 9
Dependent Claim
67 words
A control system according to any one of the preceding claims further comprising suction pressure means (18) for providing a suction pressure safety signal (LPS) when the suction pressure of the working gas at the intake to the compressor falls below a predetermined suction pressure level, the control means being responsive to the suction pressure safety signal (LPS) for inhibiting the generation of the first control signal.
Claim 10
Dependent Claim
42 words
A control system according to claim 8, wherein the suction pressure means includes means for delaying the generation of the suction pressure safety signal (LPS) for a predetermined period of time after the suction pressure falls below the predetermined suction pressure level.
Claim 11
Dependent Claim
62 words
A control system according to any one of the preceding claims, further comprising ambient temperature sensing means (24) for providing an ambient temperature signal (ATS) in response to a detected air temperature exterior to the said area below a.predetermined ambient temperature value, the control means being responsive to the ambient temperature signal (ATS) for inhibiting the generation of the first control signal.
Claim 12
Dependent Claim
99 words
A control system according to any one of the preceding claims and further comprising humidity sensing means (16) for providing a humidity signal (RHS) when the relative humidity of air in the said area is above a predetermined humidity level, the control means being responsive to the humidity signal (RHS) for generating the first control signal (43) in the absence of the first temperature signal (RAA) and the control means being responsive to the first temperature signal (RAA) and the humidity signal (RHS) for generating the second control signal (45) in the absence of the second temperature signal (RAB).
Claim 13
Dependent Claim
71 words
A control system according to any one of claims 1 to 10 and further comprising humidity sensing means (16) for providing a humidity signal (RHS) when the relative humidity of air in the said area falls below a predetermined humidity level, the control system being responsive to the humidity signal (RHS) in the absence of the first temperature signal (RAA) for generating a heat signal-(51) for re-heating the returned air. ·
Claim 14
Dependent Claim
78 words
A control system according to claim 12, further comprising mode selection means (26) for alternatively generating either an air conditioning mode signal (A/C MODE) or a heat mode signal (HEAT MODE), the control system being responsive to the heat mode signal and the absence of the air conditioning mode signal for inhibiting the generation of the first control signal (43) and for generating the heat signal (51) regardless of the presence or absence of the humidity signal (RHS).
Claim 15
Dependent Claim
65 words
- 14. A,control system according to any one of claims 6, 7, 8 or 9, wherein the control means includes latching means (130) for latching to a first latching signal output ("0") in response to a safety signal and thereafter maintaining the latching signal output even after the safety signal is terminated, the latching signal output inhibiting the generation of the first control signal (43).
Claim 16
Dependent Claim
69 words
A control system according to claim 2 characterised by a suction pressure sensing means (PDPS) for sensing a suction pressure of the compressor and for providing a pull-down pressure signal (TLS) when the suction pressure is above a pull-down pressure set point, the pull-down pressure signal preventing the generation of the second (45) or third (47) control signal until the suction pressure falls below the pull-down pressure set point.
References Cited (Backward Citations)
No citation records indexed.
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