CN1206496C - Air-cooled heat pump air-conditioning frost-melting controlling method - Google Patents
Air-cooled heat pump air-conditioning frost-melting controlling method Download PDFInfo
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- CN1206496C CN1206496C CN 03116149 CN03116149A CN1206496C CN 1206496 C CN1206496 C CN 1206496C CN 03116149 CN03116149 CN 03116149 CN 03116149 A CN03116149 A CN 03116149A CN 1206496 C CN1206496 C CN 1206496C
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- air
- evaporator
- wind speed
- defrost
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Abstract
The present invention relates to an air cooled heat pump air-conditioning frost melting controlling method which is realized by detecting the wind speed of an outlet of an evaporator. The present invention is characterized in that firstly, systems carry out analogue simulation to obtain relation between evaporation temperature and the wind speed of the outlet of the evaporator; the evaporation temperature is calculated according to the wind speed which is detected by a wind speed sensor which is arranged at the outlet of the evaporator; the surface temperature of the evaporator is obtained according to the relation between the surface temperature and the evaporation temperature of the evaporator, and then, whether frost is melted is determined according to the surface temperature of the evaporator; finally, whether frost melting ends is determined according to that whether the wind speed of the outlet of the evaporator achieves a threshold value during normal operation. The frost melting controlling method has the advantages of simplicity, easy operation and energy saving, overcomes the defect of the traditional frost melting controlling technique and well controls frost melting.
Description
Technical field
What the present invention relates to is air-cooled heat pump air-conditioning system defrosting control method, particularly a kind ofly controls defrost method constantly by measuring air-cooled heat pump air-conditioner outdoor unit evaporator outlet wind speed.Belong to Thermal Power Engineering and Refrigeration ﹠ Air-Conditioning technical field.
Background technology
With the outdoor air is the heat pump air conditioner of thermal source, and when the evaporator surface temperature was lower than 0 ℃, airborne moisture can condense into frost at evaporator surface.Frost layer covers evaporator surface, hindered contacting of coil pipe and fin and air, greatly reduces the heat transfer efficiency of heat exchanger.Along with the increase of frost thickness, duct cross-section is diminished, air quantity reduces, and heat transfer boundary condition is constantly abominable, and the evaporator surface temperature constantly reduces, thereby evaporating temperature is also constantly reduced, and heating capacity also constantly reduces.Even make the passage total blockage, heat pump can't be worked.When therefore air-cooled heat pump unit moves in the winter time, need periodically defrost, and defrost control is a wherein difficult link.
Defrost time started and concluding time are promptly determined in defrost control, become an emphasis of present heat pump air conditioner research.In the prior art, the control method that the automatic defrosting that Chen Rudong and Xu Dongsheng narrate and study in " research of refrigerating plant Defrost method " (" Tongji University's journal ", 1998 26 5 phases of volume, 566-569 page or leaf) literary composition begins and finishes mainly contains:
1) time control defrost.Rule of thumb determine defrost periods and duration,, connect defrosting device, the beginning defrost with a time controller; Defrost continues designated time intervals and cuts off defrosting device.This is a kind of general defrosting control method, but its limitation is arranged, and is higher than 0 ℃ at outdoor air dry-bulb temperature, when perhaps air humidity was very low, potential evaporation device surface did not have frosting, but Ding Shi connection defrosting device, waste energy, and influence indoor air comfort.
2) temperature difference control defrost.The temperature difference with working medium in air under the operating mode and the evaporimeter is constant substantially.After the evaporator surface frosting, the remarkable variation of conducting heat, the temperature difference between the two become big.Utilize this variation, survey air themperature and evaporating temperature respectively, send according to the temperature difference that defrost begins and termination signal with two temperature sensing elements.When making in this way, establishing a capital in advance of control system itself and temperature range is difficult, and be very sensitive to the variation of heat pump air conditioner load.The frequent connection defrosting device of meeting if the while outdoor fan is out of order up to shutdown, wastes energy.
3) minute-pressure difference control defrost.It is relevant with frosting thickness that pressure when air flows through evaporimeter falls, and the frost layer is thick more, and pressure falls big more.Like this, the pressure differential of available minute-pressure difference controller induction evaporation mode device import and export is sent the defrost commencing signal.This minute-pressure difference controller price is more expensive, for domestic air conditioning, uses the minute-pressure difference controller that cost is increased greatly, so substantially need not in the family expenses air-conditioning.
So how to use the simplest method, use lower cost, energy savings can be controlled defrost again well again, is the problem that our refrigeration air-conditioner circle generally is concerned about.
Summary of the invention
For overcoming the shortcoming of several defrosting control methods commonly used in the above-mentioned prior art, the present invention proposes a kind of method of controlling the defrost of air-cooled heat pump air-conditioning by mensuration evaporator outlet wind speed.
The present invention has at first carried out analogue simulation to the air-cooled heat pump air-conditioning, sets up off-premises station, indoor set, the simulation model of compressor and restricting element, then by pressure balance, mass balance and energy balance are coupled to system with four big parts, loop iteration then, system carries out frosting operation simulation calculation.Finally obtained evaporating temperature and outlet respective relationships:
t
0＝0.1417v
5-0.5463v
4+0.6173v
3-0.0988v
2+0.4941v-4.9040 (1)
In the formula, t
0Be evaporating temperature, ℃; V is the evaporator outlet wind speed, m/s.
Then, at off-premises station evaporator outlet place air velocity transducer is installed, in the regular hour step-length, the wind speed substitution formula 1 with measuring obtains evaporating temperature t
0
Defrosting control method commonly used all is to determine whether defrost according to the evaporator surface temperature, on the engineering, and when the evaporator surface temperature reaches-2 ℃～-3 ℃, the beginning defrost.And there are relation of plane down in evaporating temperature and evaporator surface temperature:
t
w＝t
0+Δt
w (2)
In the formula, t
wBe the evaporator surface temperature, ℃; Δ t
wPoor for evaporating temperature and evaporator surface temperature generally got Δ t
w=1.5～2 ℃.
The present invention continues to use this method, sets when the evaporator surface temperature t
wWhen being reduced to-2 ℃～-3 ℃, the beginning defrost is set t such as us
wBegin defrost when being reduced to-3 ℃.Work as the evaporating temperature that formula 1 calculates so, substitution formula 2 is such as getting Δ t
w=1.5 ℃, obtain the evaporator surface temperature, then work as t
wBegin defrost when reaching-3 ℃.
Defrost is determined according to different systems the finish time.According to engineering experience, general off-premises station outlet wind speed is 1.8m/s～2.2m/s when frost-free normally moves.According to this velocity interval, set a threshold value that finishes defrost, such as setting when wind speed end defrost during greater than 1.8m/s.
Sum up above introduction, the concrete control method of the present invention is as follows:
1) off-premises station, indoor set, compressor and the restricting element of air-cooled heat pump air-conditioning are set up simulation model respectively;
2) according to pressure balance, mass balance and principle of energy balance, system is carried out frosting operation simulation calculation, draw the evaporator evaporation temperature t
0As follows with the relation of evaporator outlet wind speed v:
t
0＝0.1417v
5-0.5463v
4+0.6173v
3-0.0988v
2+0.4941v-4.9040
3) at the off-premises station evaporator outlet air velocity transducer is installed;
4), set the evaporator surface temperature t according to specific system
wWith the evaporator evaporation temperature t
0Difference Δ t
wValue and evaporator surface temperature t
wThreshold value; Wind speed threshold value when setting-up time step-length and normal operation;
5) when air-cooled heat pump brings into operation, the wind speed substitution evaporating temperature t that in time step, air velocity transducer is measured
0In the relational expression of evaporator outlet wind speed v, obtain evaporating temperature t
0
6) the Δ t that sets according to step 4
wThe evaporating temperature t that value and step 5 obtain
0Value and relational expression t
w=t
0+ Δ t
w, obtain the evaporator surface temperature t
w
7) judge the evaporator surface temperature t of calculating
wThe value whether arrival presets;
8) if reach the value that presets, the beginning defrost; If do not reach, continue operation;
9) after the beginning defrost, when the wind speed that measures reaches the threshold value that presets, finish defrost, otherwise continue defrost.
Above-mentioned defrosting control method, not only simple, and can well energy savings, unlike time control defrost defrost like that regularly, just needing ability defrost under the situation of defrost; Also unlike temperature difference control defrost, be difficult to initialization, also insensitive to the variation of air conditioner load; Compare with minute-pressure difference control defrost simultaneously, cost is also very low.Can use very low cost, better controlled defrost.
The specific embodiment of the invention:
Come control method of the present invention is further described below in conjunction with a concrete heat pump air conditioner example.
1) off-premises station (finned-tube evaporator), indoor set (plate type heat exchanger), compressor (15hp piston compressor) and the restricting element (heating power expansion valve of refrigerating capacity 42kw) of JFLSR-350 air-cooled heat pump are set up the mathematical simulation model respectively;
2) according to pressure balance, mass balance and principle of energy balance, above-mentioned each parts are coupled to system, then system is carried out frosting operation simulation calculation, draw evaporating temperature and the evaporator outlet respective relationships is as follows:
t
0＝0.1417v
5-0.5463v
4+0.6173v
3-0.0988v
2+0.4941v-4.9040
3) air velocity transducer is installed in off-premises station (finned-tube evaporator) exit;
4) according to the actual conditions of native system, set Δ t
w=1.5 ℃, t
w=-3 ℃, i.e. t
wBegin defrost in the time of＜-3 ℃;
5) when heat pump brings into operation, getting time step is 2min, and just every 2min air velocity transducer is measured wind speed once, and the wind speed substitution formula 1 with measuring obtains evaporating temperature t
0
6) the evaporating temperature t that formula 1 is calculated
0Substitution formula 2 obtains the evaporator surface temperature t
w
7) judge the evaporator surface temperature t of calculating
wWhether less than-3 ℃;
8) if t
wWhen being less than or equal to-3 ℃, the beginning defrost if do not reach, continues operation; In the native system, when the wind speed v that a certain moment air velocity transducer measures is 0.7m/s, formula 1 calculate t
0=-4.502 ℃, substitution formula 2 calculate t
w=-3.002 ℃＜-3 ℃, this moment, heat pump began defrost;
When 9) native system did not have frosting, normal wind speed was 1.8～2.1m/s, therefore sets and finish defrost when wind speed reaches 1.8m/s;
10) after the beginning defrost,, finish defrost, otherwise continue defrost when the wind speed v that measures is greater than or equal to 1.8m/s.
Claims (3)
1, a kind of air-cooled heat pump air-conditioning defrosting control method is characterized in that this control method comprises:
1) the air-cooled heat pump air-conditioning is carried out analogue simulation, set up off-premises station, indoor set, the simulation model of compressor and restricting element;
2) according to pressure balance, mass balance and principle of energy balance, system is carried out frosting operation simulation calculation, draw the evaporator evaporation temperature t
0As follows with the relation of evaporator outlet wind speed v:
t
0＝0.1417v
5-0.5463v
4+0.6173v
3-0.0988v
2+0.4941v-4.9040
3) at the off-premises station evaporator outlet air velocity transducer is installed;
4), set the evaporator surface temperature t according to specific system
wWith the evaporator evaporation temperature t
0Difference Δ t
wValue and evaporator surface temperature t
wThreshold value; Wind speed threshold value when setting-up time step-length and normal operation;
5) when air-cooled heat pump brings into operation, the wind speed substitution evaporating temperature t that in time step, air velocity transducer is measured
0In the relational expression of evaporator outlet wind speed v, obtain evaporating temperature t
0
6) the Δ t that sets according to step 4
wThe evaporating temperature t that value and step 5 obtain
0Value and relational expression t
w=t
0+ Δ t
w, obtain the evaporator surface temperature t
w
7) judge the evaporator surface temperature t of calculating
wThe value whether arrival is set;
8) if t
wReach the value of setting, the beginning defrost; If do not reach, continue operation;
9) after the beginning defrost, when the wind speed v that measures surpasses preset threshold, finish defrost, otherwise continue defrost.
2, air-cooled heat pump air-conditioning defrosting control method according to claim 1 is characterized in that described step 4, Δ t
wSetting value be 1.5 ℃～2 ℃, t
wThreshold value be-2 ℃～-3 ℃, time step is 2 minutes, the wind speed threshold value is 1.8 meter per seconds～2.1 meter per seconds when normally moving.
3, air-cooled heat pump air-conditioning defrosting control method according to claim 1 is characterized in that described step 9, finishes defrost when wind speed v surpasses 1.8 meter per seconds after the beginning defrost.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03116149 CN1206496C (en) | 2003-04-03 | 2003-04-03 | Air-cooled heat pump air-conditioning frost-melting controlling method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03116149 CN1206496C (en) | 2003-04-03 | 2003-04-03 | Air-cooled heat pump air-conditioning frost-melting controlling method |
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| Publication Number | Publication Date |
|---|---|
| CN1448674A CN1448674A (en) | 2003-10-15 |
| CN1206496C true CN1206496C (en) | 2005-06-15 |
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| CN 03116149 Expired - Fee Related CN1206496C (en) | 2003-04-03 | 2003-04-03 | Air-cooled heat pump air-conditioning frost-melting controlling method |
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Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101984311B (en) * | 2010-08-23 | 2013-04-24 | 江苏天舒电器有限公司 | Hot-water frost preventing and defrosting device with compressor cooling |
| CN102779217B (en) * | 2012-08-06 | 2014-07-09 | 大连三洋压缩机有限公司 | Computer simulation performance computation method of refrigeration system under frosting working condition |
| CN105737389B (en) * | 2014-12-10 | 2019-06-18 | 青岛经济技术开发区海尔热水器有限公司 | Efficient defrosting method and device combining fan speed and pressure control |
| CN105042791B (en) * | 2015-08-20 | 2017-11-28 | 苏州创时云能源科技有限公司 | A kind of air-conditioner defrosting on-line monitoring and control system and method |
| CN105333577A (en) * | 2015-11-23 | 2016-02-17 | 广东美的制冷设备有限公司 | Air conditioner defrosting control method and device |
| CN106996675A (en) * | 2016-01-22 | 2017-08-01 | 广州市美控电子科技有限公司 | refrigeration temperature control intelligent defrosting control device |
| JP6590073B2 (en) * | 2016-08-22 | 2019-10-16 | 株式会社デンソー | Air cooling device and dehumidifying / humidifying device |
| KR20180052312A (en) * | 2016-11-10 | 2018-05-18 | 엘지전자 주식회사 | Refrigerator and Controlling method for the same |
| CN112050368B (en) * | 2019-06-07 | 2022-07-15 | 重庆海尔空调器有限公司 | Control method and device for defrosting of air conditioner, air conditioner and server |
| CN111707028A (en) * | 2020-07-14 | 2020-09-25 | 南京安纳杰能源科技有限公司 | Outdoor air-cooled defroster of heat pump air conditioner |
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