JP7429547B2 - heat utilization system - Google Patents

Description

The present invention relates to a heat utilization system.

Systems that utilize heat from groundwater are known (for example, Patent Documents 1 and 2).
The underground water utilization system disclosed in Patent Document 1 includes a means for pumping up and supplying underground water, a heat exchanger, a reverse osmosis membrane purification device, and a purified water receiving tank. The groundwater utilization system disclosed in Patent Document 1 further includes a first flow path system and a second flow path system, and these flow path systems can be switched. In the first flow path system, the groundwater after passing through the heat exchanger is supplied to the reverse osmosis membrane purification device, and the permeated water of the reverse osmosis membrane is stored in the purified water receiving tank. In the second channel system, groundwater is directly supplied as it is to the reverse osmosis membrane purification device, and permeated water from the reverse osmosis membrane is stored in the purified water receiving tank.

The geothermal heat utilization system disclosed in Patent Document 2 includes a pumping well, a water softening device, an outside air processing heat pump, a water-cooled heat pump using groundwater, a deaeration device, and an injection well. The geothermal heat utilization system disclosed in Patent Document 2 removes iron and manganese from groundwater using a water softening device filled with Na-type ion exchange resin, and then uses the groundwater as a heat source in a heat pump for outside air processing and a water-cooled heat pump that uses groundwater. supply The groundwater supplied as a heat source for these heat pumps is post-treated in a deaerator, returned to an injection well, and returned to the ground.

Japanese Patent Application Publication No. 2006-46677 JP2012-233636A

FIG. 2 is a graph showing an example of the relationship between the temperature of water supplied to a separation membrane such as a reverse osmosis membrane and the amount of water permeated through the separation membrane. In the graph of FIG. 2, the temperature of water supplied to the separation membrane is plotted on the horizontal axis, and the ratio of the amount of permeated water to the amount of permeated water at 15° C. is plotted on the vertical axis. As shown in FIG. 2, the higher the temperature of the water supplied to the separation membrane, the greater the amount of permeated water, and the lower the temperature of the water supplied to the separation membrane, the lower the amount of permeated water.
Therefore, if the temperature of water supplied to the separation membrane changes during water treatment by the separation membrane, it is thought that the amount of permeated water will change as well.

FIG. 3 is a schematic diagram of a conventional heat utilization system. The heat utilization system 101 shown in FIG. 3 includes a raw water tank 111, a heat exchanger 117, a membrane separation device 115, a drug addition means 118, a mineralizer 119, and a treated water tank 120 in this order from the groundwater side (raw water tank 111 side). The membrane separation device 115 also includes separation membrane modules 116, 116', and 116''.
In the heat utilization system 101, groundwater flows through a channel 121 from a well (not shown) and is supplied to a raw water tank 111. The groundwater in the raw water tank 111 is pumped by the pump 112 and flows through the channel 122, passes through the pre-filter 113, and then flows into the heat exchanger 117. In the heat exchanger 117, heat exchange is performed between the object of heat exchange and groundwater, and the heat of the groundwater is utilized. Thereafter, the groundwater flows through the channel 122, is supplied to the membrane separation device 115, and is separated into permeated water and concentrated water. The permeated water flows through a channel 123, and the concentration of components such as chlorine, pH value, hardness, etc. in the permeated water are adjusted as necessary by the chemical addition means 118 and the mineralizer 119, and stored in the treated water tank 120.

As described above, in the treatment system 101, the groundwater after passing through the heat exchanger 117 and undergoing heat exchange is supplied to the membrane separation device 115. However, the temperature of the groundwater after passing through the heat exchanger 117 tends to fluctuate under the influence of the operating rate of the heat exchanger 117 and the like. Therefore, according to the relationship between the water temperature and the amount of permeated water shown in FIG. 2, in the heat utilization system 101, the amount of permeated water in the membrane separation device 115 fluctuates.
Therefore, in the heat utilization system 101, since the temperature of the water supplied to the membrane separation device 115 and the amount of permeated water are likely to fluctuate, the concentration of components such as chlorine and organic matter in the permeated water in the treated water tank 120, and the pH Water quality such as value and hardness is unstable. In addition, even if an attempt is made to control the water quality of permeated water using the chemical addition means 118 and the mineralizer 119, the operational load for control is extremely large, making it difficult to control the water quality. Furthermore, when the heat utilization system 101 recovers and uses heat from groundwater in the winter, the water temperature after passing through the heat exchanger decreases, so the amount of permeated water in the membrane separation device 115 decreases. Unable to use water stably.

In the permeated water of the reverse osmosis membrane that passes through the first flow path system described in Patent Document 1, the groundwater after passing through the heat exchanger is supplied to the reverse osmosis membrane purification device. Therefore, for the same reason as the heat utilization system 101 shown in FIG. 3, the temperature of water supplied to the reverse osmosis membrane purification device and the amount of water permeated through the reverse osmosis membrane fluctuate due to heat exchange in the heat exchanger. Cheap. Therefore, the quality of the permeated water is not stable and it is difficult to control the water quality.
In the water softening device for the geothermal heat utilization system disclosed in Patent Document 2, groundwater is passed through a tower filled with Na-type ion exchange resin to remove Ca, Mg, Fe, and Mn ions from the groundwater. . However, water softening devices using Na-type ion exchange resin cannot remove protozoa such as Cryptosporidium, bacteria, dissolved organic matter, etc., and are insufficient as a pretreatment of groundwater, making it impossible to use groundwater as a water resource.
The present invention provides a heat utilization system in which groundwater can be used as a water resource, the quality of permeated water obtained by treating groundwater with a separation membrane is stable, and the quality of permeated water can be easily controlled.

The present invention has the following aspects.
[1] A heat utilization system that utilizes heat from groundwater, including a pretreatment means for treating the groundwater using a separation membrane, and a system provided after the pretreatment means and for treating the groundwater by the pretreatment means. A heat utilization system, comprising: a heat exchanger that performs heat exchange using the groundwater that has been collected.
[2] The heat utilization system according to [1], wherein the separation membrane is a reverse osmosis membrane or an ultrafiltration membrane.
[3] The heat utilization system according to [1] or [2], further comprising a treated water tank that stores the groundwater treated by the pretreatment means.
[4] The heat utilization system according to [3], wherein the treated water stored in the treated water tank is used as drinking water.
[5] The heat utilization system according to any one of [1] to [4], further comprising post-treatment means for treating the groundwater treated by the pre-treatment means with a chemical.
[6] The heat utilization system according to any one of [1] to [5], further comprising a mineralizer that adjusts the hardness of the groundwater treated by the pretreatment means.

According to the present invention, there is provided a heat utilization system in which groundwater can be used as a water resource, the quality of permeated water obtained by treating groundwater with a separation membrane is stable, and the quality of permeated water can be easily controlled. be done.

1 is a schematic diagram of a heat utilization system according to an embodiment. It is a graph showing an example of the relationship between the temperature of water supplied to a separation membrane and the amount of permeated water. 1 is a schematic diagram of a conventional heat utilization system.

EMBODIMENT OF THE INVENTION Hereinafter, the operating method of the reverse osmosis membrane of this invention is demonstrated by showing the embodiment example. However, the present invention is not limited to the following embodiments.
FIG. 1 is a schematic diagram of a heat utilization system 1 according to an embodiment of the present invention. The heat utilization system 1 is a system that utilizes heat from groundwater. The heat utilization system 1 includes a raw water tank 11, a membrane separation device 15, a heat exchanger 17, a chemical addition means 18, a mineralizer 19, and a treated water tank 20 in this order from the groundwater side (raw water tank 11 side).

The raw water tank 11 is a tank that stores groundwater as raw water. A raw water channel 21 and an underground water channel 22 are connected to the raw water tank 11 .
The raw water flow path 21 is a flow path for supplying groundwater to the raw water tank 11 from a well (not shown). The raw water channel 21 is provided with a pumping device (not shown). A water pumping device (not shown) pumps up groundwater from a well or the like (not shown) and supplies the groundwater to the raw water tank 11 via the raw water channel 21 .
The groundwater channel 22 is a channel for supplying groundwater in the raw water tank 11 to the membrane separation device 15. In the groundwater channel 22, a pump 12 and a pre-filter 13 are provided in this order from the groundwater side. Therefore, the groundwater in the raw water tank 11 passes through the groundwater channel 22 through the pump 12 and the prefilter 13 in this order.
In this way, the groundwater channel 22 can supply pumped groundwater to the membrane separation device 15 before supplying it to the heat exchanger 17 . Therefore, the groundwater channel 22 can supply groundwater to the membrane separation device 15 while maintaining the temperature of the groundwater without intervening any heat exchanger.

The pump 12 is for pressurizing groundwater and supplying it to the membrane separation device 15. By pressurizing groundwater using the pump 12 and supplying it to the membrane separation device 15, pretreatment of groundwater using a separation membrane becomes possible.
The pre-filter 13 is provided on the groundwater side of the membrane separator 15, and removes large impurities such as leaves and gravel, and protects the separation membrane of the membrane separator 15 from clogging, damage, etc.

The membrane separation device 15 is an example of a pretreatment means for treating groundwater using a separation membrane.
The membrane separation device 15 includes separation membrane modules 16, 16', and 16''. The separation membrane modules 16, 16', and 16'' each have a separation membrane therein. As the separation membrane, a reverse osmosis membrane or an ultrafiltration membrane is preferable because the treated water in the treated water tank 20 can be easily used as drinking water.
The membrane separation device 15 is a device that allows groundwater to permeate through the separation membranes of the separation membrane modules 16, 16', and 16'' and separates it into permeated water and concentrated water. Each of the separation membrane modules 16, 16', and 16'' is connected to each end of a branched underground water channel 22. Therefore, the groundwater in the groundwater channel 22 is supplied to the primary side of the separation membranes of the separation membrane modules 16, 16', 16''.

In the heat utilization system 1, the membrane separation device 15 is provided upstream of the heat exchanger 17, and no heat exchanger is provided upstream of the membrane separation device 15. Therefore, the groundwater can be supplied to the membrane separation device 15 while maintaining the temperature of the pumped groundwater. Normally, groundwater temperature does not fluctuate much. Therefore, in the heat utilization system 1, fluctuations in the temperature of the groundwater supplied to the membrane separator 15 are small, and fluctuations in the flow rate of permeated water in the membrane separator 15 are extremely small compared to conventional systems.

Furthermore, the separation membrane modules 16, 16', and 16'' are connected to each branched end of the permeated water flow path 23 and a concentrated water flow path 24, respectively.
The permeated water flow path 23 is a flow path for supplying permeated water from the membrane separation device 15 to the treated water tank 20 and storing it therein. Groundwater treated by the membrane separator 15, that is, permeated water flows through the permeated water channel 23. The permeated water channel 23 is provided with a heat exchanger 17, a chemical addition means 18, and a mineralizer 19 in this order. Therefore, the groundwater treated by the membrane separation device 15 passes through the permeated water flow path 23 through the heat exchanger 17 , the drug addition means 18 , and the mineralizer 19 in this order.
The concentrated water flow path 24 is a flow path for collecting the concentrated water of the separation membrane modules 16 , 16 ′, and 16 ″ and discharging it to the outside of the treatment system 1 . Concentrated water from the membrane separation device 15 flows into the concentrated water channel 24 .
In another embodiment, in order to increase the recovery rate of treated water, the concentrated water flow path is configured so that some of the concentrated water can be returned to the groundwater flow path and then processed again in the separation membrane module. You can. Alternatively, the entire amount may be treated as permeated water without producing concentrated water.

The heat exchanger 17 is provided downstream of the membrane separation device 15. In addition, the heat exchanger 17 performs heat exchange using the groundwater treated by the membrane separation device 15. Specifically, the heat exchanger 17 performs heat exchange between the groundwater treated by the membrane separation device 15 and the object to be heat exchanged. The objects to be heat exchanged are not particularly limited, but include various buildings and facilities such as general houses, hospitals, factories, schools, office buildings, agricultural facilities, livestock facilities, aquariums, botanical gardens, shopping malls, and nursing care facilities. However, the object of heat exchange is not limited to these examples.
For example, when the heat exchanger 17 is used for heating a building, heating water in a building, melting snow, etc., the heat exchanger 17 recovers heat from the groundwater treated by the membrane separation device 15 and recovers it. The generated heat is used to heat buildings and other objects subject to heat exchange.
For example, when the heat exchanger 17 is used for purposes such as cooling a building, cooling water inside a building, or cooling a refrigerant, the heat exchanger 17 supplies groundwater treated by the membrane separation device 15 with heat inside the building, etc. , which cools buildings and other objects that undergo heat exchange.

The chemical addition means 18 is an example of a post-treatment means that uses a chemical to treat groundwater that has been treated by the pre-treatment means. For example, the chemical addition means 18 mixes the underground water and the chemical after heat exchange has been performed by the heat exchanger 17 to adjust the chlorine concentration, pH, free carbonate concentration, sulfate ion concentration, ammonia nitrogen concentration, etc. Examples include modes of adjustment.
Examples of the drug include disinfectants such as sodium hypochlorite and sodium chlorite; pH adjusters such as sodium hydroxide, hydrochloric acid, and sulfuric acid. However, the drugs are not limited to these examples. One type of drug may be used alone, or two or more types may be used in combination.
In this embodiment, the drug addition means is located before the heat exchanger (primary side), but in other embodiments, the drug addition means may be located after the heat exchanger (secondary side). It may be located both before and after the heat exchanger (both the primary side and the secondary side).

The mineralizer 19 adjusts the hardness of groundwater after being treated by the pretreatment means. Examples of the mineralizer 19 include one that adjusts the hardness of groundwater by mixing at least one of calcium and magnesium with groundwater that has been treated by the membrane separation device 15. Hardness adjustment using a mineralizer may be performed depending on the pH, free carbonate concentration, and water flow rate of the underground water flowing through the water.

The treated water tank 20 is a tank that stores groundwater treated by the membrane separation device 15 as treated water. The treated water in the treated water tank 20 can be used as drinking water for the building. In this case, the heat utilization system 1 uses the treated water stored in the treated water tank 20 as drinking water.
The treated water in the treated water tank 20 can also be used as miscellaneous water, such as a water source for bathing, a water source for animals and plants, a water source for toilets, a water source for watering, and other purposes for which permeated water is used. and uses are not limited to these examples.

(effect)
In the heat utilization system 1 described above, the heat exchanger 17 is provided after the membrane separation device 15. Therefore, the temperature of the groundwater supplied to the separation membrane of the membrane separation device 15 is not affected by the heat exchange in the heat exchanger 17 and does not easily fluctuate. Therefore, the amount of water permeated through the separation membrane of the membrane separation device 15 also becomes less likely to fluctuate. As a result, the amount of permeated water through the separation membrane of the membrane separation device 15 becomes difficult to fluctuate, and the water quality such as the concentration of components such as chlorine, ammonia nitrogen, and organic matter, pH value, and hardness in the permeated water in the treated water tank 20 is stabilized. .
Furthermore, according to the heat utilization system 1, since the quality and amount of water permeated through the separation membrane are stabilized, it becomes easy to control the water quality by adding minerals and using chemicals such as chlorine.
The heat utilization system 1 also includes a membrane separation device 15 that processes groundwater using a separation membrane. Therefore, according to heat utilization system 1, protozoa such as Cryptosporidium, bacteria, dissolved organic matter, etc. can be removed from groundwater, sufficient pretreatment can be performed on groundwater, and groundwater can be fully utilized as a water resource. becomes.
Therefore, according to the heat utilization system 1, groundwater can be used as a water resource, the quality of permeated water obtained by treating groundwater with a separation membrane is stabilized, and the quality of permeated water can be easily controlled.

Since the heat utilization system 1 described above further includes the treated water tank 20, the treated water in the treated water tank 20 can be used for various purposes and uses, for example, the treated water can be used as drinking water.
The heat utilization system 1 described above further includes a drug addition means 18 and a mineralizer 19. In the heat utilization system 1, the flow rate of water permeated through the separation membrane is less likely to fluctuate and the water quality is stable, so it is easy to control the water quality by adding minerals or using chemicals such as chlorine. Therefore, according to the heat utilization system 1, the load when controlling the quality of permeated water using the chemical addition means 18 and the mineralizer 19 is reduced.

(how to use)
The heat utilization system 1 is applicable to, for example, any groundwater such as well water and underground water. The following is an example of how to use the heat utilization system 1. First, groundwater is supplied from a well or the like (not shown) to the raw water tank 11, and the pump 12 sends the groundwater through the pre-filter 13, and the separation membrane modules 16, 16', 16'' of the membrane separation device 15. supply to. Next, a heat exchanger 17 provided after the membrane separator 15 exchanges heat with the target object using the permeated water of the membrane separator 15, that is, the groundwater treated by the membrane separator 15. Make an exchange. Thereafter, the quality of the permeated water after heat exchange is adjusted using the chemical addition means 18 and the mineralizer 19 as necessary.

In the heat utilization system 1 , a heat exchanger 17 is provided downstream of the membrane separation device 15 . Therefore, even when the heat utilization system 1 is used for heating, the temperature of the groundwater supplied to the membrane separator 15 does not decrease, and the amount of permeated water does not decrease either. Therefore, the amount of permeated water in the membrane separator 15 does not decrease.
In this way, according to the heat utilization system 1, even when heat is recovered from groundwater during heating use, the amount of permeated water does not decrease. Therefore, according to the heat utilization system 1, compared with the conventional heat utilization system 101, the first channel system disclosed in Patent Document 1, etc., groundwater is treated and permeated water is obtained efficiently during heating use. It also has the effect of being able to be used effectively as a water resource.
As explained above, according to the heat utilization system 1, groundwater can be used as a water resource, the quality of permeated water obtained by treating groundwater with a separation membrane is stable, and the quality of permeated water can be easily controlled. It is possible to provide a heat utilization system.

1 Heat utilization system 11 Raw water tank 12 Pump 13 Prefilter 15 Membrane separation device 16, 16', 16'' Separation membrane module 17 Heat exchanger 18 Chemical addition means 19 Mineralizer 20 Treated water tank 21 Raw water channel 22 Groundwater channel 23 Permeation Water flow path 24 Concentrated water flow path

Claims (6)

A heat utilization system that utilizes heat from groundwater and uses the groundwater as drinking water ,
Pretreatment means for treating the groundwater using a separation membrane;
a heat exchanger that is provided after the pretreatment means and exchanges heat with a building or facility using the groundwater treated by the pretreatment means;
Equipped with
The heat exchanger recovers heat from the groundwater treated by the separation membrane and uses the recovered heat to heat the building or facility , or
The heat exchanger is a heat utilization system (provided that the groundwater treated by the pretreatment means) cools the building or facility by causing the groundwater treated by the separation membrane to remove heat from the object to be heat exchanged. (Excluding cases where groundwater returns to the heat exchanger after passing through the heat exchanger once.) The heat utilization system according to claim 1, wherein the separation membrane is a reverse osmosis membrane or an ultrafiltration membrane. The heat utilization system according to claim 1 or 2, further comprising a treated water tank that stores the groundwater treated by the pretreatment means. The heat utilization system according to claim 3, wherein the treated water stored in the treated water tank is used as the drinking water. The heat utilization system according to any one of claims 1 to 4, further comprising post-treatment means for treating the groundwater treated by the pre-treatment means using a chemical. The heat utilization system according to any one of claims 1 to 5, further comprising a mineralizer that adjusts the hardness of the groundwater treated by the pretreatment means.

Images