JP3834567B2 - Carbon dioxide gas supply system combined with exhaust heat recovery in greenhouse for horticulture - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a system for performing supply of carbon dioxide gas for promoting the growth of plants and exhaust heat recovery of exhaust gas in a greenhouse for horticulture (hereinafter referred to as a greenhouse), particularly a large greenhouse having a large area, and an operation method thereof. .
The present invention also provides a system that uses exhaust gas from a hot water heating (heating) heat source that burns hydrocarbon fuel as a carbon dioxide gas source, and performs exhaust heat recovery when heating alone without supplying carbon dioxide, and an operating method thereof. About.
[0002]
[Prior art]
An invention disclosed in Japanese Patent Application Laid-Open No. 10-229763 exists as a prior application technique related to a carbon dioxide gas supply system for exhaust heat recovery. Although there is a difference between a boiler and an engine in a combustion heat source serving as a carbon dioxide gas source, Japanese Patent Laid-Open No. 10-229763 can also be considered as an implementation of a carbon dioxide gas supply system combined with exhaust heat recovery in a greenhouse for horticulture.
However, in Japanese Patent Laid-Open No. 10-229763, in principle, the temperature range of the system circulating heat transfer fluid cannot be freely changed, and the temperature at the exhaust gas heat exchanger inlet always remains high. When carbon dioxide gas is supplied, it is necessary to exchange heat with a low-temperature heat transfer fluid, but JP-A-10-229763 cannot sufficiently cool and condense exhaust gas. Exhaust gas with insufficient cooling is too hot, causing high temperature damage to plants and air distribution pipes. For this reason, it is necessary to dilute the exhaust gas after heat exchange with outside air, but since the exhaust gas is hot, the volume is large, and in order to lower the temperature after dilution, it is necessary to introduce a considerable amount of outside air, The capacity of the carbon dioxide supply fan and its operating cost (electricity cost) are large. Moreover, since the condensation is not sufficient, there is a concern about condensation blockage of the polyethylene film distribution pipe (polyduct). As a result, there are growth variations due to uneven carbon dioxide supply to the greenhouse, and loss of crop product value due to dripping of condensed water. This is because Japanese Patent Application Laid-Open No. 10-229763 uses a single heat exchanger and a high-temperature heat transfer fluid at all times, and the actual effect is greatly different from the present application.
[0003]
[Problems to be solved by the invention]
In order to supply carbon dioxide, the exhaust gas temperature is required to be equal to or lower than its condensation point (temperature). Therefore, when supplying carbon dioxide, it is necessary to flow cold water through the exhaust gas cooling / condensing device. On the other hand, in the case of only heating without carbon dioxide supply, it is not necessary to cool and condense the exhaust gas. Therefore, it is conceivable to switch the flow path of the exhaust gas according to the supply of carbon dioxide gas. However, since the exhaust gas is high temperature, it is not only technically difficult but also unrealistic from the viewpoint of equipment cost and space. As a result, the exhaust gas is passed through the exhaust gas cooling / condensing device even when the carbon dioxide gas is not supplied, but it is necessary to pass some heat transfer fluid in order to avoid emptying of the exhaust gas cooling / condensing device. In that case, using the same cold water at the time of carbon dioxide supply as a heat transfer fluid will waste heat wastefully. Not only is the act itself an economic loss, but if cold water is produced, the energy spent on it is wasted.
Moreover, since the temperature of the heat transfer fluid exiting from the exhaust gas cooling / condensing device when supplying carbon dioxide is too low, it cannot be used for normal heating.
In the present invention, when carbon dioxide gas is supplied, the exhaust gas discharged from the boiler or the like is cooled and dehumidified by a heat exchanger (exhaust gas cooling / condensing device) and supplied to the greenhouse. When carbon dioxide is not supplied, the same apparatus is used. It aims at providing the system which collects the heat of exhaust gas so that it may contribute to the heating of a greenhouse.
[0004]
[Means for Solving the Problems]
According to the first aspect of the present invention, there is provided an exhaust heat recovery and combined carbon dioxide supply system applied to a greenhouse for facility horticulture, which is provided at an exhaust gas outlet of a boiler or the like for supplying carbon dioxide to the greenhouse. A high temperature side heat exchanger is attached, and the heat exchanger is connected to the low temperature side heat exchanger via a heat medium fluid flow path automatic pump set and a heat medium fluid circulation pump via the heat medium fluid flow channel, side heat exchanger is connected to the high temperature side heat exchanger by its flow path for a heat transfer fluid, also the high temperature-side heat exchanger through the automatic valve set for the heating medium flow switching by its flow path for a heat transfer fluid greenhouse heating The hot water circuit is connected to a hot water circuit return hot water pipe, and the hot water pipe is connected to a heat medium fluid flow path between an automatic valve set for switching the heat medium flow path and a circulation pump for the heat medium fluid, and a low temperature side heat exchanger. Is connected to a cooling tower for cold water by a flow path of cold water, and the cooling tower is circulated for cooling by a flow path of cold water. Through the amplifier is solved by providing a heat recovery combined carbon dioxide gas supply system characterized in that it is connected to the low-temperature heat exchanger.
[0005]
According to the invention described in claim 2 , the above-mentioned problem is a waste heat recovery combined carbon dioxide supply system applied to a greenhouse for facility horticulture, which is an exhaust gas outlet of a boiler or the like for supplying carbon dioxide to the greenhouse. The high temperature side heat exchanger is attached to the low temperature side heat exchanger via a three-way automatic valve and a heat medium fluid circulation pump via a heat medium fluid flow path, and the low temperature side heat exchanger is The high temperature side heat exchanger is connected to the high temperature side heat exchanger by the flow path of the heat medium fluid, and is connected to the hot water circuit return pipe for heating in the greenhouse through the three-way automatic valve by the flow path of the heat medium fluid. The return hot water pipe is connected to the flow path of the heat transfer fluid between the three-way automatic valve and the circulation pump for the heat transfer fluid, and the low temperature side heat exchanger is connected to the cooling tower for cold water through the flow path of cold water. It is connected to the cold side heat exchanger through the circulation pump for cooling the cold water flow path It is solved by providing a heat recovery combined carbon dioxide gas supply system comprising.
[0006]
The above object is also achieved, according to the third aspect of the present invention, the flow path through the cold water injection automatic valve from the cold water inlet is connected to the low-temperature heat exchanger, further drains from the cold-side heat exchanger It is solved by providing the exhaust- heat-recovery combined carbon dioxide gas supply system according to claim 1 , further comprising a structure connected to the flow path to reach.
[0007]
The above object is further, according to the invention of claim 4, wherein, when supplying carbon dioxide to the greenhouse, the flow path and the heat medium of the heat transfer fluid between the hot-side heat exchanger and the low temperature-side heat exchanger A circulation channel that forms a circulation channel that is connected via a fluid circulation pump and that is connected between a low-temperature heat exchanger and a cooling tower for cold water via a cooling water channel and a cooling circulation pump The heat transfer fluid that has taken heat from the high-temperature and high-humidity exhaust gas discharged from the boiler, etc., by the high-temperature side heat exchanger is led to the low-temperature side heat exchanger, and heat is supplied to the cold water to provide the high-temperature side heat exchanger. is solved by providing a heat recovery combined carbon dioxide gas supply system according to any one of claims 1 to 3, characterized in that return to.
[0008]
The above object is further, according to the invention of claim 5, wherein, when the recovery of the exhaust gas waste heat concatenates the flow path of the heat transfer fluid in the middle of the heating hot water circuit Kaeyu tube, heating hot water circuit A bypass passage is formed from the return pipe to the heating medium fluid circulation pump, the low temperature side heat exchanger, and the high temperature side heat exchanger circulation path to the heating hot water circuit return pipe. In addition, a part of the heating hot water flowing in the heating hot water circuit return hot water pipe is led to the bypass flow path, and the heat medium is deprived of heat from the high temperature / humidity exhaust gas discharged from the boiler etc. by the high temperature side heat exchanger. is solved by providing a heat recovery combined carbon dioxide gas supply system according to any one of claims 1 to 3, characterized in that to return the fluid to the hot water circuit Kaeyu tube for heating.
[0009]
[Action]
A high temperature side heat exchanger 11 that takes heat from exhaust gas and a low temperature side heat exchanger 12 that cools the heat medium fluid with cold water are cascade-connected as shown in FIG. Cold water is supplied from a cooling source.
When supplying carbon dioxide, the heat transfer fluid is circulated through a closed flow path connecting the two heat exchangers 11 and 12, and the high temperature side heat exchanger 11 is operated as an exhaust gas cooling / condensing device.
In the case of heating only, the flow path connecting the two heat exchangers 11 and 12 is incorporated in a heating hot water circuit heated by a hot water heating heat source such as a boiler. The hot water for heating is used as a heat transfer fluid, and the low temperature side heat exchanger 12 does not transfer heat (does not flow cold water). Exhaust heat of exhaust gas can be recovered by passing the high temperature side heat exchanger 11 through the high temperature side heat exchanger 11 before returning the hot water whose temperature has been reduced by applying heat to the greenhouse to the hot water heating source such as a boiler. 11 can be operated as an exhaust heat recovery device to save energy.
That is, the heat transfer fluid is the hot water for heating itself. Depending on the necessity of carbon dioxide supply, the flow of the heat transfer fluid by the automatic valve is linked to the operation of the cooling source.
[0010]
【Example】
FIG. 1 shows the entire volume of the exhaust heat recovery and combined carbon dioxide gas supply system according to the present invention. In the figure, the white arrow 10 is the flow direction of exhaust gas, 11 is a high temperature side heat exchanger, 12 is a low temperature side heat exchanger, 13 is a cooling tower for cold water, 14a is a circulation pump for heat transfer fluid, and 14b is for cold water. Circulation pumps 151, 152, 153, and 154 are manual valves, 15a is an automatic valve set for switching the heat medium flow path, 15b is an automatic valve for injecting cold water, 16 is a check valve, 17 is a drainage groove, and 18 is a cold water inlet. , 19 is a flow path of the heat transfer fluid, 20 is a hot water circuit return pipe for heating, 21 is a flow path of the cold water, and a black arrow indicates the flow direction of the hot water for heating, the heat transfer fluid, and the cold water.
[0011]
Configuration of the exhaust heat recovery combined carbon dioxide gas supply system according to the present invention, fitted with a hot-side heat exchanger 11 to the exhaust gas outlet of the boiler, the heat exchanger 11 is a heat medium flow path switching by the flow passage 19 of the heat transfer fluid The low temperature side heat exchanger 12 is connected to the high temperature side heat exchanger 11 by the heat medium fluid flow path 19 via the automatic valve set 15a and the circulation pump 14a for the heat medium fluid. Further, the high temperature side heat exchanger 11 is connected to the heating hot water circuit return hot water pipe 20 through the heat medium fluid flow path automatic valve set 15a by the heat medium fluid flow path 19, and the return hot water pipe 20 is reversed. It is connected to the heat medium fluid flow path 19 between the heat medium flow path switching automatic valve set 15a and the heat medium fluid circulation pump 14a via the stop valve 16, and the low temperature side heat exchanger 12 is connected to the cold water flow path. 21 is connected to the cold water cooling tower 13 through the manual valve 151 by The cooling tower 13 is the cold water circulating pump 14b by cold water flow passage 21 is connected to the low-temperature heat exchanger 12 through the manual valve 152.
[0012]
Further, as a cooling source of another system, a path from the cold water inlet 18 through the manual valve 153 and the cold water injection automatic valve 15b is connected to the cold water flow path 21 between the manual valve 152 and the low temperature side heat exchanger 12. The flow path that reaches the drainage groove 17 via the manual valve 154 is connected between the low-temperature side heat exchanger 12 and the manual valve 151.
To the cold water inlet 18, ground water or agricultural water is used as cold water for cooling.
[0013]
Referring to FIG. 2 when supplying carbon dioxide, the heating medium flow switching automatic valve set 15a closes the connection to the heating hot water circuit return pipe 20 and at the same time exchanges between the high temperature side heat exchanger 11 and the low temperature side heat exchange. A circulation channel is formed between the vessels 12. The heat medium fluid filled in the heat medium flow path 19 is heated by the heat medium fluid circulation pump 14a to the high temperature side heat exchanger 11, the heat medium flow path switching automatic valve set 15a, the heat medium fluid circulation pump 14a, It circulates to the low temperature side heat exchanger 12 and the high temperature side heat exchanger 11. The high-temperature and high-humidity exhaust gas discharged from the boiler or the like is deprived of heat by the heat transfer fluid in the high-temperature side heat exchanger 11 and partially condensed, and is supplied to carbon dioxide supply. The heat transfer fluid deprived of heat from the exhaust gas by the high temperature side heat exchanger 11 is guided to the low temperature side heat exchanger 12 by the heat medium fluid circulation pump 14a, and heats the cold water and returns to the high temperature side heat exchanger 11. . The temperature of the heat transfer fluid is lowered by the low temperature side heat exchanger 12 so that the exhaust gas can be sufficiently cooled and condensed by the high temperature side heat exchanger 11. The cold water obtained from the heat transfer fluid in the low temperature side heat exchanger 12 is cooled to the original temperature in the cold water cooling tower 13 and returned to the low temperature side heat exchanger 12 by the cold water circulation pump 14b. In this way, the high temperature and high humidity exhaust gas can be changed to a state suitable for carbon dioxide supply.
[0014]
In the case of only heating (FIG. 3), the heating medium flow switching automatic valve set 15a closes the circulation flow path from the high-temperature side heat exchanger 11 to the heat transfer fluid circulation pump 14a and simultaneously returns the heating hot water circuit. The flow path to the hot water pipe 20 is opened. Thereby, the bypass from the hot water circuit return hot water pipe 20 to the check valve 16, the heat medium fluid circulation pump 14 a, the low temperature side heat exchanger 12, the high temperature side heat exchanger 11 and the heating hot water circuit return hot water pipe 20 is bypassed. The heat transfer fluid that has been formed between the heat exchangers 11 and 12 circulates in the heating hot water circuit again as the heating hot water. A part of the hot water for heating flowing through the heating hot water circuit return hot water pipe 20 by the heat medium fluid circulation pump 14a is led into the flow path, and the check valve 16, the heat medium fluid circulation pump 14a, the low temperature side The heat enters the high temperature side heat exchanger 11 through the heat exchanger 12, takes heat from the high temperature and high humidity exhaust gas discharged from the boiler or the like, and returns to the hot water circuit return hot water pipe 20 for heating. Then, the hot water for heating is circulated through a circuit that is heated by a heating heat source such as a boiler, is consumed in the greenhouse, and returns to the upstream side of the hot water circuit return hot water pipe 20 again. In this way, it is possible to realize an energy saving effect that enables exhaust heat recovery with the same equipment, although it is a full-fledged carbon dioxide supply system. On the other hand, hot water for heating is usually operated at 60 to 80 ° C., but the temperature is too high to cool and condense the exhaust gas. In this case, the exhaust gas emitted from the high temperature side heat exchanger 11 is suitable for supplying carbon dioxide. Absent.
[0015]
The operation of only carbon dioxide supply and heating is switched by an instruction from the host system of this system, but the switching of the heat medium flow switching automatic valve set 15a stops the operation of the heat medium fluid circulation pump 14a. The operation can be switched smoothly. Since the heat transfer fluid is always flowing, there is no need to temporarily stop the operation of a heat source such as a boiler because of fear of overheating of the high temperature side heat exchanger 11 at the time of operation switching. Therefore, controllability is good. Further, at the time of operation switching, discharge or to hot water circuit out of hot water for heating, since the contamination of the cooling source of cold water hot water circuits in does not occur, it does not inhibit the water quality management of hot water for heating. If proper water quality control is not maintained, heat sources for warm water (heating) such as boilers and hot water circuits for heating are at risk of corrosion and damage.
[0016]
As a cooling source, ground water or agricultural water (cooling source of another system) can be used in addition to a cooling tower. In the case of groundwater or agricultural water, the cold water injection automatic valve 15b is operated to operate the cold water side of the low temperature side heat exchanger 12, but the manual valve 153 of the cold water inlet 18 is opened, and two manual operations of the cold water flow path 21 are performed. By closing the valves 151 and 152 and forming a flow path from the cold water inlet 18 to the low temperature side heat exchanger 12 and the drainage groove 17, a cooling source that does not use the cold water cooling tower 13 can be secured. Therefore, by providing two cooling sources as shown in the figure, it is possible to place the other as a backup in addition to the cooling tower.
In addition, the heat medium flow path switching automatic valve set 15a may be a three-way automatic valve 22 as shown in FIG. The check valve 16 may be omitted.
[0017]
【The invention's effect】
As described above, according to the present invention, one exhaust heat recovery and combined carbon dioxide supply system is installed, and when supplying carbon dioxide, a heat medium is provided in a closed flow path connecting the two heat exchangers 11 and 12. Since the fluid is circulated and the high temperature side heat exchanger 11 is operated as an exhaust gas cooling / condensing device, carbon dioxide gas dehumidified at low temperature is obtained, and carbon dioxide gas is supplied to an appropriate place in the greenhouse by a polyduct or the like. Can do. In the case of heating only, the flow path connecting the two heat exchangers 11 and 12 is incorporated in the heating hot water circuit, and the hot water that has been cooled by applying heat to the greenhouse is returned to the heat source such as a boiler before being returned to the heat source. By passing through the heat exchanger 11, exhaust heat recovery of the exhaust gas becomes possible and energy saving is realized.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.
FIG. 2 is a system explanatory diagram showing an operation state when supplying carbon dioxide gas according to the present invention.
FIG. 3 is a system explanatory diagram showing an operation state during exhaust heat recovery according to the present invention.
FIG. 4 is a schematic configuration diagram showing another embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Arrow which shows direction of flow of exhaust gas High temperature side heat exchanger 12 Low temperature side heat exchanger 13 Cooling tower for cold water 14a Circulating pump for heat medium fluid 14b Circulating pump for cold water 151, 152, 153, 154 Manual valve 15a Heat medium flow Automatic valve set for path switching 15b Automatic valve for cold water injection 16 Check valve 17 Drain groove 18 Cold water inlet 19 Heat medium fluid flow path 20 Hot water circuit return hot water pipe 21 Cold water flow path 22 Three-way automatic valve

Claims (5)

A carbon dioxide gas supply system combined with exhaust heat recovery applied to greenhouses for horticulture,
A high-temperature side heat exchanger (11) is attached to an exhaust gas outlet of a boiler or the like for supplying carbon dioxide to the greenhouse, and the heat exchanger (11) is used for switching the heat medium flow path by a heat medium fluid flow path (19). The low temperature side heat exchanger (12) is connected to the low temperature side heat exchanger (12) via an automatic valve set (15a) and a heat medium fluid circulation pump (14a). the coupled to the high temperature side heat exchanger (11), also the high-temperature side heat exchanger (11) flow path of the heat transfer fluid (19) by a greenhouse through the heat medium flow path switching automatic valve set (15a) It is connected to a hot water circuit return hot water pipe (20) for heating, and the hot water pipe (20) is connected between the automatic valve set (15a) for heat medium flow switching and the circulation pump (14a) for the heat medium fluid. The low-temperature side heat exchanger (12) is connected to the flow path (19) of the chilled water by the cold water flow path (21). Coupled to the column (13), the cooling tower (13) is characterized in that it is connected via a circulation pump for cooling (14b) by cold water flow path (21) low-temperature heat exchanger (12) Carbon dioxide gas supply system combined with exhaust heat recovery. A carbon dioxide gas supply system combined with exhaust heat recovery applied to greenhouses for horticulture,
A high temperature side heat exchanger (11) is attached to an exhaust gas outlet of a boiler or the like for supplying carbon dioxide gas to the greenhouse, and the heat exchanger (11) is a three-way automatic valve (22) by a heat medium fluid passage (19). And a low temperature side heat exchanger (12) via a circulation pump (14a) for the heat medium fluid, and the low temperature side heat exchanger (12) is connected to the high temperature side heat exchanger by the flow path (19) of the heat medium fluid. The high temperature side heat exchanger (11) is connected to the hot water circuit return hot water pipe (20) for heating in the greenhouse via the three-way automatic valve (22) by the flow path (19) of the heat transfer fluid. The return hot water pipe (20) is connected to the heat medium fluid passage (19) between the three-way automatic valve (22) and the heat medium fluid circulation pump (14a), and the low temperature side heat exchanger (12). ) Is connected to the cold water cooling tower (13) by the cold water flow path (21), and the cooling tower (13) is connected to the cold water flow path (13). Heat recovery combined carbon dioxide gas supply system, characterized in that it is connected via a circulation pump for cooling (14b) low-temperature heat exchanger (12) by 1). A flow path going through the cold water inlet (18) of cold water for injection Automatic valve (15b) is connected to the low-temperature heat exchanger (12), leading to the drainage groove (17) from further low temperature-side heat exchanger (12) 3. The exhaust heat recovery combined carbon dioxide gas supply system according to claim 1 , further comprising a structure connected to the flow path. When supplying carbon dioxide to the greenhouse, the hot-side heat exchanger (11) and the low-temperature heat exchanger (12) a flow path for the heat transfer fluid between the (19) and the heat transfer fluid circulation pump (14a ) And a cooling water pump (14b) between the low temperature side heat exchanger (12) and the cooling water cooling tower (13). The heat transfer fluid that has deprived the heat from the high-temperature and high-humidity exhaust gas discharged from the boiler or the like by the high-temperature side heat exchanger (11) is formed in the low-temperature side heat exchanger (12 ) to lead exhaust heat recovery combined carbon dioxide gas supply system according to any one of claims 1 to 3, characterized in that return to the hot-side heat exchanger gives heat (11) to the cold water. When recovering exhaust heat of exhaust gas flow path of the heat transfer fluid (19) is connected in the middle of the heating hot water circuit Kaeyukan (20), the heating medium from the heating hot water circuit Kaeyukan (20) The heating fluid circulating pump (14a), the low-temperature side heat exchanger (12), and the high-temperature side heat exchanger (11) are circulated by the fluid channel (19) through the circulation channel (20). ), A part of the hot water for heating flowing through the heating hot water circuit return pipe (20) is led to the bypass flow channel, and exhaust gas of high temperature and high humidity discharged from the boiler or the like. The exhaust heat according to any one of claims 1 to 3, wherein the heat transfer fluid deprived of heat from the high temperature side heat exchanger (11) is returned to the heating hot water circuit return hot water pipe (20). recovery also used carbon dioxide gas supply system.

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