JP2010014375A - Defrosting method of heating tower - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a defrosting method of a heating tower effectively using brine used for defrosting. <P>SOLUTION: The defrosting method includes processes of: supplying first brine cooled by heat exchange with a refrigerant by an evaporator 5 to a heat exchanger 21 of a closed-type heating tower 2 and heating the first brine by performing heat exchange with the atmosphere; heating second brine stored in a heat storage tank 3; shutting off the supply of the first brine from the evaporator 5 to the heat exchanger 21; supplying the second brine in the heat storage tank 3 into the heat exchanger 21 to defrost the surface of the heat exchanger 21 after the supply of the first brine is shut off; and resuming the supply of the first brine to the heat exchanger 21 and mixing at least part of the second brine with the first brine and supplying them to the evaporator 5 after the defrosting of the surface of the heat exchanger 21 is completed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for defrosting a heating tower.

The hermetic heating tower is a device that heats the brine by exchanging the brine flowing in the internal heat exchanger with the outside air. However, the outside air cooled by the heat exchange with the brine is condensed and the heating tower is heated. Frost may form on the surface of the heat exchanger. When frost forms on the surface of the heat exchanger in this way, the contact area between the brine and the outside air becomes small, and there is a problem that the heat exchange efficiency decreases. In order to solve this problem, for example, in Patent Document 1, a brine tank that stores brine heated by an electric heater is connected to a heating tower, and the frosting occurs on the surface of the heat exchanger of the heating tower. A heating tower system is disclosed that melts frost on the surface of the heat exchanger by sending brine heated from above to the heat exchanger.
Japanese Unexamined Patent Publication No. Sho 63-318455

  However, in the heating tower defrosting method, the brine used for the defrosting after the defrosting operation is completed is returned to the brine tank again, and the normal heating tower operation is resumed. There was a problem that it could not be used effectively.

  Then, this invention makes it a subject to provide the defrost method of the heating tower which utilizes effectively the brine used for the defrost.

  The defrosting method for a heating tower according to the present invention is made in order to solve the above-mentioned problem, and the first brine cooled by exchanging heat with the medium to be heated in the heat source side device is hermetically heated. A step of heating by supplying heat to the tower and exchanging heat with the atmosphere, a step of heating the second brine accommodated in the heat storage tank, and a second step from the heat source side device to the heat exchanger. The step of shutting off the supply of the first brine and the supply of the first brine, and then supplying the second brine in the heat storage tank into the heat exchanger to defrost the surface of the heat exchanger. And after completion of the process and defrosting of the surface of the heat exchanger, the supply of the first brine to the heat exchanger is resumed and at least a part of the second brine is mixed with the first brine. And supplying to the heat source side device.

  According to the above method, the heated second brine can be used not only for defrosting the heat exchanger surface but also mixed with the first brine and supplied to the heat source side device. Thus, the second brine used for defrosting can be used effectively. The “heat source side device” is not particularly limited as long as it exchanges heat between the brine and the medium to be heated. For example, an evaporator of a refrigerator, an evaporator of an air conditioning heat pump, Examples include an evaporator of a hot water supply heat pump.

  The defrosting method can take various forms, for example, a step of providing a plurality of heat exchangers of the hermetic heating tower and another hermetic seal while defrosting one heat exchanger surface. Heating the first brine by means of a heating tower. According to this method, the heat source side device can be continuously operated.

  The second brine is preferably heated by exchanging heat with the refrigerant in a condenser of a heat pump unit in which a compressor, a condenser, an expansion valve, and an evaporator are connected in order and the refrigerant circulates.

  As apparent from the above, according to the heating tower defrosting method of the present invention, the brine used for defrosting can be used effectively.

  Hereinafter, an embodiment of a defrosting method for a heating tower according to the present invention will be described with reference to the drawings. FIG. 1 shows a block diagram of a heating tower system.

  As shown in FIG. 1, the heating tower system 1 includes a heating tower 2 that heats the first brine by exchanging heat with the outside air, a heat storage tank 3 that houses the second brine, and a heat storage tank 3. And a heat pump unit 4 for heating the brine.

  The heating tower 2 has a heat exchanger 21 in which the first brine flows, and a fan 22 is installed on the heat exchanger 21. By operating the fan 22, an air flow is generated such that outside air that has entered from the side rises toward the fan 22. In addition, a feed pipe P1 that sends the first brine heated by exchanging heat with the outside air by the heat exchanger 21 to the evaporator (heat source side device) 5 of the refrigerator is provided above the heat exchanger 21. Connected to the lower portion of the heat exchanger 21 is a return pipe P2 to which the first brine cooled by heat exchange with the refrigerant (heated medium) flowing through the evaporator 5 returns. A first on-off valve V1 for opening and closing the feed pipe P1 is attached to the feed pipe P1, and a second on-off valve V2 for opening and closing the return pipe P2 is attached to the return pipe P2. The return pipe P2 is provided with a first circulation pump 6 for circulating the first brine in a circuit connecting the evaporator 5 and the heat exchanger 21.

  The heat storage tank 3 is configured to accommodate the second brine therein, and a supply pipe P3 for supplying the second brine to the heat exchanger 21 of the heating tower 2 is connected to the upper part thereof, and the lower part thereof is connected to the lower part. Is connected to a discharge pipe P4 for returning the second brine discharged from the heat exchanger 21 to the heat storage tank 3. A third on-off valve V3 that opens and closes the supply pipe P3 is attached to the supply pipe P3, and a fourth on-off valve V4 that opens and closes the discharge pipe P4 is attached to the discharge pipe P4. The discharge pipe P4 is provided with a second circulation pump 7 for circulating the second brine in a circuit connecting the heat exchanger 21 of the heating tower 2 and the heat storage tank 3.

  The heat pump unit 4 is configured by connecting a compressor 41, a condenser 42, an expansion valve 43, and an evaporator 44 in an annular shape, and a refrigerant circulates therein. The condenser 42 extends in the heat storage tank 3 and is configured to exchange heat between the refrigerant flowing in the condenser 42 and the second brine in the heat storage tank 3.

  Next, the operation method of the heating tower system 1 described above will be described with reference to the drawings. FIG. 2 is an explanatory view for explaining the operation method of the heating tower system 1 when the second brine in the heat storage tank 3 is heated, and FIG. 3 is a case where the first brine is heated in the heat exchanger 21 of the heating tower 2. FIG. 4 is an explanatory diagram for explaining the operation method of the heating tower system 1 in the case where the surface of the heat exchanger 21 of the heating tower 2 is defrosted, and FIG. It is explanatory drawing explaining the operating method of the heating tower system 1 in the case of restarting the heating of a brine with a heating tower after frost operation. In the open / close valve and the three-way valve in each drawing, the blacked-out portion indicates the closed state, and the unfilled portion indicates the open state.

  First, a method for heating the second brine in the heat storage tank 3 by the heat pump unit 4 will be described with reference to FIG.

  As shown in FIG. 2, the refrigerant circulates clockwise in the heat pump unit 4. More specifically, first, the refrigerant is compressed by the compressor 41 so that the refrigerant becomes a high-temperature and high-pressure gas, and the refrigerant is sent to the condenser 42. The high-temperature refrigerant gas sent to the condenser 42 dissipates heat to the second brine in the heat storage tank 3 to heat the second brine, and the refrigerant gas itself is condensed and sent to the expansion valve 43. The refrigerant sent to the expansion valve 43 is rapidly reduced in pressure by the expansion valve 43 to become low temperature and low pressure, and is sent to the evaporator 44. In the evaporator 44, the refrigerant takes heat from the outside air by exchanging heat with the outside air, evaporates, and is sent again to the compressor 41 to become high-temperature gas. The above process is repeated until the brine in the heat storage tank 3 reaches a predetermined temperature. In addition, it is preferable to perform the heating of the brine in the thermal storage tank 3 by this heat pump unit 4 at night when cheap late-night electric power can be used.

  Next, a method for heating the first brine by the heating tower 2 will be described with reference to FIG.

  As shown in FIG. 3, when the first brine is heated by the heating tower 2, the first and second on-off valves V1 and V2 are opened, and the third and fourth on-off valves V3 and V4 are closed. State. Then, by operating the first circulation pump 6, the first brine is circulated clockwise in a circuit connecting the heating tower 2 and the evaporator 5, and the fan 22 of the heating tower 2 is operated so that the outside air is circulated. Enters the side of the heating tower 2 and forms an air flow so as to flow upward toward the fan 22. By setting in this way, the first brine that has flowed to the heating tower 2 is heated by exchanging heat with the outside air that enters from the side of the heating tower 2 and flows upward in the heat exchanger 21. The The brine heated in the heating tower 2 is sent to the evaporator 5 of the refrigerator through the feed pipe P1. The first brine sent to the evaporator 5 dissipates heat to the refrigerant flowing in the evaporator 5 and heats the refrigerant, whereby the first brine itself is cooled, and is again heated through the return pipe P2. 2 is returned to the second heat exchanger 21. In addition, in the heat exchanger 21 of the heating tower 2, frosting starts to occur on the surface of the heat exchanger 21 when the outside air falls below the dew point, but frosting on the surface of the heat exchanger 21 occurs by continuing the above cycle for a long time. Since the area of the formed portion is increased and the heat exchange efficiency is reduced, the heat exchanger 21 needs to be defrosted.

  Next, a defrosting method for melting frost attached to the surface of the heat exchanger 21 of the heating tower 2 described above will be described with reference to FIG.

  As shown in FIG. 4, during the defrosting operation, first, the first circulation pump 6 is stopped, the first and second on-off valves V1 and V2 are closed, and the first to the heat exchanger 21 from the evaporator 5 is closed. Block the supply of 1 brine. Further, the fan 22 of the heating tower 2 is also stopped. Then, the third and fourth on-off valves V3 and V4 are opened, the second circulation pump 7 is operated, and the second brine is rotated counterclockwise in the circuit connecting the heat storage tank 3 and the heating tower 2. To circulate. By setting in this way, the high temperature 2nd brine discharged | emitted from the upper part of the thermal storage tank 3 is sent into the heat exchanger 21 from the lower part of the heat exchanger 21 of the heating tower 2 via the supply pipe P3. . The high-temperature second brine flows from the lower part to the upper part of the heat exchanger 21 to heat and melt the frost attached to the surface of the heat exchanger 21. And the 2nd brine cooled by heating frost is discharged | emitted from the upper part of the heat exchanger 21, and is returned in the thermal storage tank 3 from the lower part of the thermal storage tank 3 via the discharge pipe P4. In addition, although the temperature of the 2nd brine in the thermal storage tank 3 falls by repeating the said cycle, the temperature of this 2nd brine fell to the grade which cannot defrost the heat exchanger 21 surface efficiently. In that case, it is preferable to operate the heat pump unit 4 again to heat the second brine in the heat storage tank 3.

  When the above cycle is repeated and the defrosting of the heat exchanger 21 of the heating tower 2 is completed, then, as shown in FIG. 5, the second circulation pump 7 is stopped and the third and fourth on-off valves V3, V4 is closed and the circulation of the second brine is stopped. And the heating of the refrigerant | coolant which flows through the inside of the evaporator 5 is restarted by making the 1st and 2nd on-off valves V1 and V2 into an open state, and operating the 1st circulation pump 6. FIG. At this time, the second brine remaining in the heat exchanger 21 is mixed with the first brine and sent to the evaporator 5.

  As described above, according to the present embodiment, the high temperature second brine used for melting the frost of the heat exchanger 21 is mixed with the first brine to increase the temperature of the first brine, and thereby the evaporator 5. Therefore, the refrigerant in the evaporator 5 can be heated more efficiently.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to these, A various change is possible unless it deviates from the meaning of this invention. For example, in the above embodiment, only one heating tower 2 is installed, but a plurality of heating towers 2 can be installed. The case where the second heating tower 2 'is further added to the above embodiment and two heating towers 2 are installed will be described with reference to FIG. As shown in FIG. 6, when the second heating tower 2 ′ is further installed in the heating tower system 1 of the above embodiment, the first three-way valve V5 is provided in the feed pipe P1, and the second three-way valve is provided in the return pipe P2. V6, a third three-way valve V7 is installed in the supply pipe P3, and a fourth three-way valve V8 is installed in the discharge pipe P4. The first three-way valve V5 has a second feed pipe P1 ′, the second three-way valve V6 has a second return pipe P2 ′, the third three-way valve V7 has a second supply pipe P3 ′, and a fourth feed pipe P1 ′. The second discharge pipe P4 ′ is connected to the three-way valve V8. The second feed pipe P1 ', return pipe P2', supply pipe P3 ', and discharge pipe P4' are connected to the heat exchanger 21 'of the second heating tower 2'. The second feed pipe P1 ′ has a fifth on-off valve V1 ′, the second return pipe P2 ′ has a sixth on-off valve V2 ′, and the second supply pipe P3 ′ has a seventh on-off valve. An eighth on-off valve V4 ′ is installed in V3 ′ and the second discharge pipe P4 ′. By installing the second heating tower 2 ′ in this way, the second heating tower 2 ′ flows through the evaporator 5 while the heat exchanger 21 of the first heating tower 2 is defrosted. The refrigerant can be heated. Each of the three-way valves V5 to V8 may be a header type header valve.

  In the said embodiment, although the 2nd brine in the thermal storage tank 3 is heated by the heat pump unit 4, the heating of this 2nd brine is not restricted to the heat pump unit 4 in particular, For example, well-known, such as an electric heater The heating means can be used.

It is a lineblock diagram showing the heating tower system concerning this embodiment. It is explanatory drawing explaining the heating method of a 2nd brine. It is explanatory drawing explaining the heating method of a 1st brine. It is explanatory drawing explaining the defrosting method of a heat exchanger. It is explanatory drawing explaining the method to send the 1st brine which mixed the 2nd brine to the evaporator. It is a block diagram which shows the heating tower system which concerns on other embodiment.

Explanation of symbols

2 Heating tower 21 Heat exchanger 3 Heat storage tank 4 Heat pump unit 5 Evaporator (heat source side device)

Claims (3)

A step of heating the first brine cooled by exchanging heat with the medium to be heated in the heat source side device by supplying the heat to the heat exchanger of the sealed heating tower and exchanging heat with the atmosphere;
Heating the second brine contained in the heat storage tank;
Shutting off the supply of the first brine from the heat source side device to the heat exchanger;
After blocking the supply of the first brine, supplying the second brine in the heat storage tank into the heat exchanger to defrost the surface of the heat exchanger;
After the defrosting of the surface of the heat exchanger is completed, the supply of the first brine to the heat exchanger is resumed, and at least a part of the second brine is mixed with the first brine to be on the heat source side. Supplying to the device;
A defrosting method for a closed heating tower, comprising: A step of providing a plurality of heat exchangers for the enclosed heating tower;
Heating the first brine by another enclosed heating tower while defrosting one heat exchanger surface;
The defrosting method for a closed heating tower according to claim 1, further comprising:   The heating of the second brine is performed by heat exchange with the refrigerant in a condenser of a heat pump unit in which a compressor, a condenser, an expansion valve, and an evaporator are connected in order and the refrigerant circulates. Or the defrosting method of the enclosed heating tower of 2 or 2.

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