JP3126424B2 - Heat source equipment using a heating tower - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antifreeze solution which does not freeze at the outside air temperature in winter, is brought into gas-liquid contact with the outside air in a heating tower to collect heat from the outside air, and the heated antifreeze solution is used as a water-side heat exchanger for a heat pump device. The present invention relates to a heat source facility in which a heat pump is operated by passing a liquid through an (evaporator) to thereby process a heating and hot water supply load of a building.

[0002]

2. Description of the Related Art Heat source water is circulated through a water-side heat exchanger of a heat pump device.
The so-called water heat source air-conditioning system, which performs cooling and heating by functioning as an evaporator during heating, has become widespread, but in this system, the heated heat source water is radiated by a cooling tower during cooling operation, and cooled during heating operation. Usually, the heat source water is heated by another heat source device. This water heat source method has the advantage that cold or warm heat can be stored by using a heat storage water tank, and is also reasonable in cooling operation because heat can be released by a cooling tower. However, the heating operation requires use of fossil fuel by a boiler or the like or heating of a heat source water by electric power, so that there is a problem that equipment cost and energy consumption are larger than a method using air as a heat source.

On the other hand, heat pump devices using air as a heat source are widely used mainly for home and business use. However, in a district cooling / heating system or a large-capacity system of a large building, there is a problem of an installation space due to a large air heat exchanger. The problem of frost formation in the air heat exchanger during the severe winter is associated. Stopping heating or reducing heating capacity during the defrosting operation impairs the comfort of the living environment in office building equipment. In particular, in a district heating and cooling facility in which the unit price of heat supply is determined by a contract, a decrease in the heating capacity and a stoppage of the heating during the defrosting operation will reduce costs.

For this reason, a method has been proposed in which a cooling operation is performed by a water heat source heat pump system, and at the same time, a cooling tower (cooling tower) used in the cooling operation is caused to function as a heating tower in a heating operation to operate a heat pump device. I have. That is, in the cooling operation, the heat source water heated by the heat pump device is radiated to the outside air by the cooling tower, and in the heating operation, the heat source liquid cooled by the heat pump device is collected from the outside air by the heating tower. That is,
As a whole, it is a system that processes heating and hot water supply load using air as a heat source even in winter.

In this case, since the outside air temperature is generally low during the heating operation, in order to collect heat from the low temperature outside air, the heat source liquid supplied to the heating tower needs to be lower than the outside air temperature. , Often below zero degrees Celsius. Therefore, this heat source liquid uses an antifreeze liquid that does not freeze even at zero degrees C or lower. As such an antifreeze, for example, the same kind of brine as that used when producing cold water at a temperature of 0 ° C. or lower by a refrigerator, for example, an aqueous solution in which ethylene glycol, propylene glycol, calcium chloride, or the like is dissolved, is used. Is considered suitable. In this method, heat energy can be recovered from a low outside air temperature by circulating antifreeze between the water-side heat exchanger of the heat pump device and the heating tower, reducing the heating capacity and stopping heating during defrosting operation. Etc. can be improved. In this method,
Since it is not necessary to use antifreeze in the cooling operation season in the summer or the middle period, normal cooling water is used in the cooling season, and use of the antifreeze is limited to only the heating operation season in winter.

[0006]

As the cooling tower used in the cooling season, an open type in which gas and liquid are brought into direct contact with the outside air is generally used because of its high efficiency. When used as a heating tower in the season, there is a problem that antifreeze is diluted. For example, when the antifreeze liquid cooled to below 0 ° C is brought into direct contact with the low-temperature, high-humidity outdoor air in winter to heat it to near the outside air temperature, the moisture in the external air moves into the antifreeze liquid, and the concentration of the antifreeze liquid gradually decreases. (The antifreeze is diluted).

When the concentration of the antifreeze is low, the freezing point of the antifreeze is increased, which causes a freezing trouble. Also,
When the concentration of the antifreeze is reduced to about 30% or less, there is a problem that microorganisms are degraded by bacteria and fungi, and the odor is also generated. Conversely, since the kinematic viscosity of a high-concentration antifreeze rapidly increases, if the operation is performed at a higher concentration than necessary, there is a problem in that the transport power of a pump or the like is increased and extra running costs are required.

As a method of controlling the concentration of antifreeze, there is a method in which the concentration of antifreeze is monitored from time to time, and when an operator determines that the concentration has decreased, an ethylene glycol stock solution is supplied.
This not only makes it impossible to control the amount of antifreeze liquid, but also leads to constant freezing. Operating the antifreeze at a higher concentration than necessary to prevent freezing also requires extra running costs due to an increase in kinematic viscosity and an increase in hygroscopicity.

An object of the present invention is to solve the above-mentioned problem when a heating tower is used as a heat source facility.

[0010]

According to the present invention, there is provided a heating tower for bringing an antifreeze into gas-liquid contact with the outside air, a first heat pump device for collecting heat from the antifreeze heated by the heating tower, A heat storage tank for storing the heat collected by the first heat pump device by using water as a medium, and a second heat pump device for collecting heat from the water in the heat storage tank. A heat source using a heating tower that circulates and supplies the heat medium for processing the load and circulates and supplies the water in the heat storage tank to the evaporator. Provide equipment.

[0011]

FIG. 1 shows an embodiment of the equipment of the present invention. Reference numeral 1 denotes a heating tower having the same configuration as the open cooling tower. That is, the antifreeze is sprayed from the water spray device 2 toward the filling layer 3, and the outside air passing through the inside of the filling layer 3 and the antifreeze liquid come into direct gas-liquid contact by the driving of the fan 4. As a result, the low-temperature antifreeze liquid exchanges heat with the outside air, heats up to near the outside air temperature, and accumulates in the lower water tank 5. As antifreeze,
Although the same ethylene glycol aqueous solution as the refrigerator brine is used, other antifreeze as described above may be used.

Reference numeral 6 denotes a first heat pump device. The first heat pump device 6 and the heating tower 1 form a heat recovery cycle from air. The first heat pump device 6 is a device in which a refrigerant circulates through a compressor 7 → a condenser 8 → an expansion valve 9 → an evaporator 10 → a compressor 7. The condenser 8 and the evaporator 10 are a heat exchanger between the refrigerant and the liquid. It is. The antifreeze in the lower water tank 5 of the heating tower 1 is passed through the evaporator 10, the heat is removed from the antifreeze, and the refrigerant evaporates and is sucked into the compressor 7. On the other hand, the cooled antifreeze is circulated by the pump 11 to the spraying device 3 of the heating tower 1.
The antifreeze circuit that circulates through the heating tower → the evaporator 10 of the first heat pump device → the heating tower will be referred to as an antifreeze liquid circulation path 12. The refrigerant discharged from the compressor 7 is condensed in the condenser 8, and the heat of condensation is radiated to the water passing therethrough.

Reference numeral 13 denotes a heat storage tank for storing water (in some cases, ice-water slurry). The water in the heat storage tank 13 is sent to the condenser 8 of the first heat pump device 6 by the pump 14, and the water heated in the condenser 8 is returned to the heat storage tank 13 via the water spray device 15. The heat storage tank 13 → the condenser 8 of the first heat pump device 6 → the circulation water path of the heat storage tank 13 will be referred to as a first circulation water path 16.

By the above-described series of operations of the antifreeze circulation circuit 12, the first heat pump device 6, and the first circulation water path 16, heat is supplied to the heat storage tank 13 using air as a heat source, and heat is stored therein.

The hot water stored in the heat storage tank can be used directly for heating and supplying hot water to the building. In this case, however, the temperature of the water supplied to the load side needs to be at least 7 ° C. Depending on the load situation, it may be difficult to maintain this water temperature. Therefore, in the facility of the present invention, a second heat pump device 18 for generating supercooled water (cold water depending on the temperature of the heat storage tank 13) from the water in the heat storage tank 13 and simultaneously producing hot water is provided.

The second heat pump device 18 is a heat pump in which the refrigerant circulates in the order of compressor 19 → condenser 20 → expansion valve 21 → evaporator 22 → compressor 19. The condenser 20 receives heat from the heating / hot water supply load side. Return water is passed, and the warm water heated here is supplied to the heating hot water supply load. This load-side circulation channel is indicated by 23.

The evaporator 22 of the second heat pump device 18 supercools the water in the heat storage tank 13 to 0 ° C. or less. By making the supercooled water, fine ice is stored in the heat storage tank 13. Supplied. That is, the evaporator 22 is configured as a supercooler composed of a shell-and-tube heat exchanger, the refrigerant of which is passed through the expansion valve 21 of the second heat pump device 18 is supplied to the shell side, and the refrigerant from the heat storage tank 13 is supplied to the tube side. Water is passed by the pump 26. If the inner wall temperature of the tube through which this water (tap water) flows is maintained between -5.8 ° C and 0 ° C or lower, regardless of the temperature and amount of water continuously introduced into the tube, the tube will The supercooled water 24 supercooled to 0 ° C. or less can be continuously discharged from the tube outlet without freezing.

Therefore, in the shell of the evaporator 22, the cooling capacity is maintained such that the inner wall temperature of each tube is maintained at minus 5.8 ° C or more and zero ° C or less by heat removal when the refrigerant passing through the expansion valve 21 evaporates. Is controlled. This control can be easily performed by controlling the pressure of the evaporating refrigerant.
In addition, a full liquid type supercooler that evaporates in a state where the refrigerant liquid coexists in the shell may be used. In this case, the boiling phenomenon results in an effective supercooler.

Since the supercooled water 22 is discharged at a temperature of 0 ° C. or less, fine ice precipitates due to the drop impact. Therefore, in the heat storage tank, the ice accumulates as sherbet-like ice, but since the fine ice coexists with the water, the ice melting property is good, and the ice is immediately melted while the first circulation channel 16 is operating. The water temperature in the tank will be lowered. In some cases, ice making may accumulate in the tank in preference to ice making, which floats near the water surface and allows water to be extracted from the bottom. A water path circulating through the heat storage tank 13 → evaporator 22 (supercooler) → heat storage tank 13 is indicated by a second circulation water path 27.

As described above, the heating tower 1
The heat taken from the outside air to the first heat pump device 6 through the antifreeze liquid circulation path 12 from the outside is supplied as hot water to the heat storage tank 13 through the water in the first circulation water path 16. Is cooled to supercooled water by the supercooler 22 of the second heat pump device 18 and returns to the heat storage tank, so that low-temperature water is supplied to the condenser 8 of the first heat pump device 6. As a result, the evaporator 10 of the first heat pump device 6 can also send the lower-temperature antifreeze to the heating tower 1. In other words, even if the compression ratio of the heat pump is small, heat can be collected from low-temperature outside air.

On the other hand, also in the second heat pump device 18, since the heat is pumped to the heat medium (usually water) of the load side circulation water channel 23 by using the hot water in the heat storage tank as a heat source, the compression ratio may be small, and the evaporator may be used. Since it is a supercooler that produces supercooled water, cold heat can be returned to the heat storage tank in the form of ice, and even if the tank is small, this heat storage tank becomes a good thermobank. As a result, the pumping of heat to the load-side circulating water channel 23 can be performed stably irrespective of fluctuations in the outside air condition.

By arranging a heat exchanger in the first circulating water passage 16 extending from the heat storage tank 13 to the condenser 8 of the first heat pump device 6, the facility can be used for multiple purposes. For example, the heat exchanger 29 in the figure is a liquid / liquid heat exchanger in which the antifreeze in the antifreeze circulation circuit 12 is appropriately passed. The term “appropriate” refers to a case where the difference between the water temperature of the first circulation channel 16 and the outside air temperature is large. For example, when the outside air temperature is significantly higher than the water temperature of the first circulation water passage 16, heat can be directly taken from the outside air even while the first heat pump device 6 is operating or stopped. If the temperature of the first circulation channel 16 is higher than the outside air temperature,
Since this hot water can heat the antifreeze,
When the antifreeze comes into contact with the outside air in the heating tower 1, the water in the antifreeze evaporates to the outside air. by this,
Concentration operation of antifreeze can be performed. In this case, of course, the operation of the first heat pump device 6 is stopped.

The heat exchanger 30 is a heat exchanger for recovering exhaust heat. By sending various types of heat generated inside the building to the heat exchanger 30 using an appropriate heat medium, the waste heat of the building can be recovered.

The heat exchanger 31 is a heat exchanger for processing a cooling load. Thus, when low-temperature heat storage water exists in the heat storage tank 13, it can be used as a cooling heat source for cooling.

[0025]

According to the equipment of the present invention having the above configuration,
It has the following excellent effects. Heat is taken from the outside air in the heating tower, but on the heating and hot water supply load side, the water in the heat storage tank is used by the second heat pump device (up to the supercooling area).
Since the heat source is used as the heat source, there is no sudden change in the heat source, and the hot water on the load side can be generated stably irrespective of the outside air condition.

The sherbet-like ice is generated by the supercooler and the heat can be stored by the latent heat, so that the heat storage tank can be made compact (small capacity). Even if there is residual ice in the heat storage tank, it is possible to produce hot water on the load side. Therefore,
The heat storage tank functions as a good thermobank. Also, since it is sherbet-like ice, it has good thaw characteristics, the water temperature in the heat storage tank is stable and low, and heat is applied to this low-temperature water through the antifreeze circulation path and the first circulation path. This can be used for cooling loads in some cases, and heat can be recovered from low-temperature exhaust heat.

[0027] Since the two cycles of the first heat pump device and the second heat pump device are independent, there is a great degree of freedom in operation, and simultaneous operation of both or only one of them can be performed in the open air condition, the heat storage condition, or the like. It can be used properly according to the load situation.

As the water in the heat storage tank, general city water can be used, introduction is easy, and no special cooling unit is required in the tank. And the water temperature of the heat storage tank can be stably positioned at around 0 to 7 ° C, and does not become lower than 0 ° C.

In addition, when the outside air condition is good (when the outside air temperature is high and the humidity is low), the operation of concentrating the antifreeze liquid can be performed. In addition, even when the outside air is at a low temperature and high humidity, heat can be collected from the outside air by using the low-temperature water in the tank. can do.

[Brief description of the drawings]

FIG. 1 is an overall view showing an arrangement of heat source equipment using a heating tower according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating tower 6 First heat pump device 7 Compressor of first heat pump device 8 Condenser of first heat pump device 9 Expansion valve of first heat pump device 10 Evaporator of first heat pump device 12 Antifreeze circulation circuit 13 Heat storage tank 16 One circulation channel 18 Second heat pump device 19 Compressor for second heat pump device 20 Condenser for second heat pump device 21 Expansion valve for second heat pump device 22 Evaporator (supercooler) for second heat pump device 23 Load side circulation water channel 27 Second circulation channel

Claims (6)

(57) [Claims] 1. A heating tower for bringing an antifreeze into gas-liquid contact with the outside air, a first heat pump device for collecting heat from the antifreeze heated by the heating tower, and a heat collected by the first heat pump device. A heat storage tank for storing heat by using water as a medium, and a second heat pump device for collecting heat from the water in the heat storage tank. A heat medium for processing a heating hot water supply load is circulated to a condenser of the second heat pump. And a heat source equipment utilizing a heating tower, wherein the water in the heat storage tank is circulated and supplied to the evaporator, and the evaporator is configured as a supercooler for producing supercooled water of 0 ° C. or less. 2. The first heat pump device comprises a refrigerant circulating through a compressor, a condenser, an expansion valve, an evaporator, and a compressor. An antifreeze is circulated and supplied to the evaporator, and the water in the heat storage tank is supplied to the condenser. The heat source equipment according to claim 1, which is circulated and supplied. 3. The evaporator of the second heat pump device according to claim 1, wherein the evaporator comprises a shell-and-tube heat exchanger, a coolant is supplied into the shell, and water is passed through the tube. Heat source equipment. 4. The water in the heat storage tank passes through a heat exchanger,
The first heat pump unit of the condenser through the back into the storage tank, the heat source equipment according to claim 1, 2 or 3 this is the heat exchanger returns antifreeze from heating tower is subjected fed. 5. The water in the heat storage tank passes through a heat exchanger,
The heat source equipment according to claim 1, 2, 3 or 4, wherein the heat is returned to the heat storage tank via the condenser of the first heat pump device, and waste heat of the building is given to the water by the heat exchanger. 6. The water in the heat storage tank passes through a heat exchanger,
The heat source equipment according to claim 1, 2, 3, 4, or 5, wherein the heat load is returned to the heat storage tank via the condenser of the first heat pump device, and the cooling load of the building is processed by the heat exchanger.