CN102679494B - Control method of low temperature refrigeration of rooftop air conditioning unit - Google Patents
Control method of low temperature refrigeration of rooftop air conditioning unit Download PDFInfo
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- CN102679494B CN102679494B CN201210134465.7A CN201210134465A CN102679494B CN 102679494 B CN102679494 B CN 102679494B CN 201210134465 A CN201210134465 A CN 201210134465A CN 102679494 B CN102679494 B CN 102679494B
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Abstract
The invention discloses a control method of low temperature refrigeration of a rooftop air conditioning unit. The method includes the steps that a first mechanical pressure switch with an off value P1 and an on value P2 is additionally arranged on an exhaust pipe; a second mechanical pressure switch with an off value P3 and an on value P4 is additionally arranged on an air returning pipe; the unit performs refrigeration operation, and two fans operate simultaneously when a exhaust pressure value is larger than or equal to P2; when the exhaust pressure value is equal to or smaller than P1, the first mechanical pressure switch is off, and a first fan stops the service; when an air returning pressure value is equal to or smaller than P3, the second mechanical pressure switch is off, and an indoor fan stops the service; when the air returning pressure value is equal to or larger than P4, the second mechanical pressure switch is on, an alternating current contactor of a second fan pulls in, and the second fan operates alone. According to the control method of the low temperature refrigeration of the rooftop air conditioning unit, refrigerants which are not evaporated completely can be prevented from entering and damaging a compressor during the low temperature refrigeration operation.
Description
Technical field:
The present invention relates to field of air conditioning, is a kind of three-phase blower fan roof Top Air-conditioning Unit cryogenic refrigeration control method specifically.
Background technology:
Existing roof air-conditioning is because the refrigerating capacity that field of employment requires is larger, general indoor and outdoor blower motor all adopts three phase electric machine to drive blower fan, and it basic composition is compressor, condenser, outdoor twin shaft flow fan, throttling arrangement, evaporimeter and indoor centrifugal blower and forms.During refrigerating operaton, air-conditioning unit is according to refrigeration principle, by compressor work by heat from indoor transfer to outdoor.When the roof air conditioner group kind of refrigeration cycle of prior art is normally moved, outdoor twin shaft flow fan, indoor centrifugal blower, compressor be normally operation all.
At present for roof air-conditioning in actual use, be generally when outdoor temperature is high, require air-conditioning to carry out refrigerating operaton, when outdoor temperature is low, require heating operation.But some Code in Hazardous Special Locations, when outdoor temperature is low during even lower than 0 °, still requires air-conditioning unit to carry out refrigerating operaton.Such as large places of special heat-radiating amount such as machine room, forges, it require indoor and outdoor separately, require again indoor environment temperature to remain on 18～30 ° of left and right, in the time of due to indoor machine or equipment operation, constantly dispelling the heat in capital, causes indoor temperature constantly to raise, thereby affect the service life of machine or affect workman's operating efficiency, this just requires air conditioner group in the situation that environment temperature is low, also needs to carry out refrigerating operaton.And the roof air-conditioning of prior art, under low temperature environment, during air-conditioning unit operation because environment temperature is low, the high-temperature gas pressure that causes compressor to be discharged is on the low side, again after throttling, the pressure of cold-producing medium is lower, after often entering evaporimeter, the evaporating pressure evaporating temperature that causes on the low side is far below 0 °, and when evaporating temperature during lower than 0 ° by the condensate water making on evaporimeter, slowly become frost, thereby reduce room air and pass through evaporimeter, cause cold-producing medium fully heat exchange flash to gas completely, band liquid enters compressor, make compressor carry out hydraulic compression and cause the most at last the too fast damage of compressor.
Summary of the invention:
The object of the invention is to for prior art not enoughly, provide a kind of and under low temperature environment, can effectively prevent that the cold-producing medium not evaporating completely from entering compressor and damaging the three-phase blower fan roof Top Air-conditioning Unit cryogenic refrigeration control method of compressor during refrigerating operaton.
In order to solve the problems of the technologies described above, the technical solution that the present invention adopts is: the control method of a kind of roof air conditioner group (three-phase blower fan) cryogenic refrigeration, it comprises the steps:
(1) on the blast pipe of unit, increasing a cut off value is P
1, connection value is P
2the first mechanical pressure switches, terminals of described the first mechanical pressure switches are connected on L1 line, after one end of another terminals and the first blower fan A.C. contactor KM1 coil is connected, connect on N line;
(2) on the muffler of the evaporator outlet of unit, increasing a cut off value is P
3, connection value is P
4the second mechanical pressure switches, terminals of described the second mechanical pressure switches are connected on L1 line, after one end of another terminals and the second blower fan A.C. contactor KM2 coil is connected, connect on N line;
(3) unit carries out refrigerating operaton, and the pressure on mechanical pressure switches Real-Time Monitoring blast pipe, when exhaust pressure value is more than or equal to P
2time, two blower fans (the first blower fan, the second blower fan) move simultaneously; When exhaust pressure value is equal to or less than P
1time, described the first mechanical pressure switches disconnects, and the first blower fan A.C. contactor disconnects, the first blower fan is out of service; When back pressure value is equal to or less than P
3time, described the second mechanical pressure switches disconnects, and the second blower fan A.C. contactor disconnects outdoor fan and shuts down; When back pressure value is equal to or greater than P
4time, described the second mechanical pressure switches is closed, second blower fan A.C. contactor adhesive the second blower fan isolated operation.
Adopt above method, roof Top Air-conditioning Unit cryogenic refrigeration control method of the present invention compared with prior art, has following remarkable advantage and beneficial effect:
When air-conditioning unit carries out cold operation, when exhaust pressure value is equal to or less than P
1time, described the first mechanical pressure switches disconnects, and the first blower fan A.C. contactor disconnects, the first blower fan is out of service, to reduce the heat exchange with outdoor air, thereby improves the operating pressure of unit, and then improves evaporating pressure; When environment temperature further reduces, when back pressure value is equal to or less than P
3time, described the second mechanical pressure switches disconnects, and the second blower fan A.C. contactor disconnects outdoor fan and shuts down, thereby stops the heat exchange of outdoor air; When outdoor fan shuts down, back pressure value is equal to or greater than P
4time, described the second mechanical pressure switches is closed, and the second blower fan A.C. contactor is inhaled and the second blower fan isolated operation, and unit works on; When environment temperature raises, atmospheric pressure value is more than or equal to P
2time, described the first mechanical pressure switches is closed, two blower fans move simultaneously, unit recovers normal operation: the present invention controls the start and stop of blower fan by the force value of unit, control the evaporating pressure of air-conditioning unit, thereby avoiding causing because evaporating pressure is too low in the situations such as cold-producing medium evaporates not exclusively in evaporimeter, evaporimeter frosting cold-producing medium band liquid to enter carries out hydraulic compression in compressor, cause the most at last the phenomenon of the too fast damage of compressor to occur, has improved the cryogenic refrigeration operation conditions of air-conditioning unit.
And method of the present invention is easy easily, safe and reliable, need not change the controller of unit, only need to increase by two mechanical pressure switches.
As improvement, the force value of described the first mechanical pressure switches is P
1and P
2be 0.9MPa～1.4MPa, and P
1< P
2; The force value of described the second mechanical pressure switches is P
3and P
4be 0.15MPa～0.4Mpa, and P
3< P
4; By repetition test, prove, when this pressure limit, can not be with liquid operation by reasonable assurance unit;
As further improvement, the cut off value P of described the first mechanical pressure switches
1for 1.0MPa, closing value P
2for 1.3MPa; The cut off value P of described the second mechanical pressure switches
3for 0.25MPa, closing value P
4for 0.4MPa, by repetition test, prove, when this pressure limit, can well guarantee that unit is not with liquid operation;
As further improving again, unit or multi-compressor unit for double compressor system, in the same position of the other system of unit, increase described first, second mechanical pressure switches (all increasing mechanical pressure switches in the same position of the system of single compressor) and also the mechanical pressure switches line of described same position is cascaded, as long as there is a system mechanics pressure switch to move all the start and stop to blower fan, control.
As improvement, for the heat pump air conditioner unit with heat-production functions, be connected on L1 line and the first blower fan A.C. contactor KM1 after cross valve commutation signal line is in parallel with described the first mechanical pressure switches; Described the second mechanical pressure switches is placed on evaporator outlet to the muffler of cross valve import, when unit carries out heating operation, cross valve obtain electric after, KM1, by direct adhesive, does not need to detect the state of described the first mechanical pressure switches; During heating operation, owing to commutating, evaporator outlet is high-pressure side to cross valve import (evaporimeter of refrigerating operaton), described the second mechanical pressure switches is in closed position, therefore when carrying out heating operation, two outdoor fans all move (the single cooler group that is discussed earlier, herein for the unit with heat pump functional, when carrying out heating operation, air-conditioning will equally with common unit move, and that is to say has increased mechanical pressure switches and have the unit of cryogenic refrigeration function, do not affect normal heating operation).
Accompanying drawing explanation:
Fig. 1 is the system schematic of patent roof Top Air-conditioning Unit cryogenic refrigeration control method of the present invention.
Fig. 2 is the electrical wiring schematic diagram of the control blower fan start and stop of patent roof Top Air-conditioning Unit cryogenic refrigeration control method of the present invention.
As shown in Figure 1: 1, compressor, 2, blast pipe, the 3, first mechanical pressure switches, 4, four-way change-over valve, 5, outdoor heat exchanger, 6 outdoor aerofoil fans, 7, throttling arrangement, 8 indoor centrifugal blowers, 9, indoor heat exchanger, 10, the second mechanical pressure switches, 11, muffler, 12, gas-liquid separator; 13, the first blower fans, 14. second blower fans, 15. low tension switches, 16. high-voltage switch gears.
The specific embodiment:
Below in conjunction with the drawings and specific embodiments, patent of invention roof Top Air-conditioning Unit cryogenic refrigeration control method is described in further details, but the present invention is not limited only to following specific embodiment: as shown in Figure 1, the air conditioner group system schematic diagram of roof Top Air-conditioning Unit cryogenic refrigeration control method of the present invention, wherein compressor 1, blast pipe 2, four-way change-over valve 4, outdoor heat exchanger 5, outdoor aerofoil fan 6, throttling arrangement 7, indoor centrifugal blower 8, indoor heat exchanger 9, muffler 11, gas-liquid separator 12; , the first blower fan 13, the second blower fans 14, low tension switch 15, high-voltage switch gear 16, forms the conventional roof air conditioner group of industry, is not described in detail in this; The machine set system figure described in above-mentioned accompanying drawing 1 of take is example, and the control method that the present invention adopts is as follows: (Fig. 2 is shown in by concrete electrical wiring schematic diagram)
(1) on the blast pipe 2 of unit, increasing a cut off value is P
1, connection value is P
2the first mechanical pressure switches 3, P
1, P
2numerical value can be 0.9MPa～1.4MPa, this embodiment P
1for 1.0MPa, P
2for 1.3MPa; Terminals of described the first mechanical pressure switches are connected on L1 line, after another terminals and the series connection of the first blower fan A.C. contactor KM1 coil, connect on N line; And for source pump, cross valve commutation signal line is in parallel with described the first mechanical pressure switches 3 after, then be connected on N line with the first blower fan A.C. contactor KM1;
(2) on the muffler 11 of the evaporator outlet of unit, increasing a cut off value is P
3, connection value is P
4the second mechanical pressure switches 10, P
3, P
4numerical value can be 0.15MPa～0.4MPa, this embodiment P
3for 0.25MPa, P
4for 0.4MPa; Terminals of described the second mechanical pressure switches are connected on L1 line, after the coil series connection of the A.C. contactor KM2 of another terminals and the second blower fan 14, are connected on N line;
(3) when air-conditioning unit carries out refrigerating operaton, when outdoor temperature is lower while being equal to or less than 1.0MPa compared with exhaust pressure value, described the first mechanical pressure switches 3 disconnects, and the A.C. contactor of the first blower fan disconnects, the first blower fan 13 is out of service, and unit carries out single fan operation; When environment temperature further reduces, when back pressure value is equal to or less than 0.25MPa, described the second mechanical pressure switches 10 disconnects, and the second blower fan 14 A.C. contactors disconnect, and unit outdoor fan all shuts down; After outdoor fan shuts down, when back pressure value is equal to or greater than 0.4MPa, described the second mechanical pressure switches 10 closures, the second blower fan 14 A.C. contactor adhesives, unit recovers isolated operation; When environment temperature raises, when atmospheric pressure value is more than or equal to 1.3MPa, described mechanical pressure switches 3 closures, two blower fans move simultaneously, unit recovers normal operation: the present invention controls the start and stop of blower fan by the force value of unit, control the evaporating pressure of air-conditioning unit, thereby in evaporation, evaporation not exclusively, cold-producing medium band liquid enters the phenomenon appearance of carrying out hydraulic compression in compressor, causing the most at last the too fast damage of compressor in the situation such as evaporimeter frosting, has improved the cryogenic refrigeration operation conditions of air-conditioning unit to avoid causing because evaporating pressure is too low cold-producing medium.
The present invention is on the basis of conventional air-conditioning, only need to increase the low cost of two mechanical pressure switches, do not need controller again to develop, by control rational range of pressure values can make air-conditioning unit energy under low temperature environment safety carry out refrigerating operaton, method is very easy, with low cost.
Claims (5)
1. a control method for roof air conditioner group cryogenic refrigeration, is characterized in that: it comprises the steps:
(1) cut off value of the upper increase of blast pipe (2) at unit is P
1, connection value is P
2the first mechanical pressure switches (3), terminals of described the first mechanical pressure switches (3) are connected on L1 line, after one end of another terminals and the first blower fan (13) A.C. contactor KM1 coil is connected, connect on N line;
(2) at the muffler (11) of the evaporator outlet of unit, upper to increase a cut off value be P
3, connection value is P
4the second mechanical pressure switches (10), terminals of described the second mechanical pressure switches (10) are connected on L1 line, after one end of another terminals and the second blower fan (14) A.C. contactor KM2 coil is connected, connect on N line;
(3) unit carries out refrigerating operaton, the pressure on mechanical pressure switches Real-Time Monitoring blast pipe, and when exhaust pressure value is more than or equal to P2, two blower fans move simultaneously; When exhaust pressure value is equal to or less than P
1time, described the first mechanical pressure switches (3) disconnects, and the first blower fan (13) A.C. contactor disconnects, and the first blower fan (13) is out of service; When back pressure value is equal to or less than P
3time, described the second mechanical pressure switches (10) disconnects, and the second blower fan (14) A.C. contactor disconnects, and outdoor fan shuts down; When back pressure value is equal to or greater than P
4time, described the second mechanical pressure switches (10) closure, the second blower fan (14) A.C. contactor adhesive, the second blower fan isolated operation.
2. the control method of roof air conditioner group according to claim 1 cryogenic refrigeration, is characterized in that: the cut off value P of described the first mechanical pressure switches (3)
1, connection value P
2for 0.9MPa ~ 1.4MPa, and P
1< P
2; The cut off value P of described the second mechanical pressure switches (10)
3, connection value P
4be 0.15 MPa ~ 0.4Mpa, and P
3< P
4.
3. the control method of roof air conditioner group according to claim 2 cryogenic refrigeration, is characterized in that: the cut off value P of described the first mechanical pressure switches (3)
1be 1.0 MPa, closing value P
2be 1.3 MPa, the cut off value P of described the second mechanical pressure switches (10)
3be 0.25 MPa, closing value P
4be 0.4 Mpa.
4. the control method of roof air conditioner group according to claim 1 cryogenic refrigeration, it is characterized in that: for unit and the multi-compressor unit of double compressor system, all in the same position of the system of single compressor, increase mechanical pressure switches, and the mechanical pressure switches of same position is cascaded, as long as the mechanical pressure switches action that has a single compressor system all to blower fan start and stop control.
5. the control method of roof air conditioner group according to claim 1 cryogenic refrigeration, it is characterized in that: for the heat pump air conditioner unit that has heat-production functions, be connected on L1 line and the first blower fan (13) A.C. contactor KM1 after cross valve commutation signal line is in parallel with described the first mechanical pressure switches (3); Described the second mechanical pressure switches (10) is placed on evaporator outlet to the muffler (11) of cross valve import.
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|---|---|---|---|
| CN201210134465.7A CN102679494B (en) | 2012-05-03 | 2012-05-03 | Control method of low temperature refrigeration of rooftop air conditioning unit |
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|---|---|---|---|
| CN201210134465.7A CN102679494B (en) | 2012-05-03 | 2012-05-03 | Control method of low temperature refrigeration of rooftop air conditioning unit |
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| CN102679494B true CN102679494B (en) | 2014-04-02 |
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Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103398444B (en) * | 2013-07-01 | 2016-12-28 | Tcl空调器(中山)有限公司 | Air conditioner low-temperature refrigeration method and device |
| CN104833056B (en) * | 2015-05-11 | 2017-10-31 | 广东美的暖通设备有限公司 | Control method and control system for the outdoor fan of air conditioner |
| CN109595850B (en) * | 2019-01-08 | 2021-09-07 | 广东美的暖通设备有限公司 | Control method and air conditioning system |
| CN111520895B (en) * | 2020-04-29 | 2021-04-06 | 珠海格力电器股份有限公司 | Control method of condensing fan and refrigerating unit |
| CN113028574B (en) * | 2021-04-20 | 2022-04-08 | 宁波奥克斯电气股份有限公司 | Control method and control device for improving reliability of air conditioner and air conditioner |
| CN113098067A (en) * | 2021-05-08 | 2021-07-09 | 国网上海市电力公司 | Roof fan device and intelligent power generation and temperature and humidity control system thereof |
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| CN101650064A (en) * | 2008-08-14 | 2010-02-17 | 海尔集团公司 | Low-temperature refrigeration air conditioner and wind speed control method thereof |
| CN101788214A (en) * | 2009-12-18 | 2010-07-28 | 艾默生网络能源有限公司 | Air conditioning condenser |
| CN102121741A (en) * | 2011-03-14 | 2011-07-13 | 广东美的电器股份有限公司 | Multi-connection air conditioning unit and control method thereof during small-load refrigeration running |
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2012
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101650064A (en) * | 2008-08-14 | 2010-02-17 | 海尔集团公司 | Low-temperature refrigeration air conditioner and wind speed control method thereof |
| CN101788214A (en) * | 2009-12-18 | 2010-07-28 | 艾默生网络能源有限公司 | Air conditioning condenser |
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Address after: 315191 Zhejiang city of Ningbo province Jiangshan town Yinzhou District Mingguang Road No. 1166 Patentee after: NINGBO AUX ELECTRIC CO., LTD. Address before: 315191 Zhejiang city of Ningbo province Jiangshan town Yinzhou District Mingguang Road No. 1166 Patentee before: Ningbo AUX Electric Co., Ltd. |