JP2008304141A - Heat storage snow melting system using solar heat - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat storage snow melting system using solar heat and a control method of the heat storage snow melting system using solar heat, capable of inexpensively acquiring, storing and using sufficient natural energy such as ground heat. <P>SOLUTION: This heat storage snow melting system using solar heat is composed of a primary part composed of a heat storage tank formed in the ground, a heat storage tank circulating heat exchange pipe for circulating water or an antifreeze to the inside going round the inside and outside of the heat storage tank and a liquid sending pump for sending the water and the antifreeze in the heat storage tank circulating heat exchange pipe, and a secondary part composed of a roadbed buried in the ground surface, a roadbed circulating heat exchange pipe for circulating the water or the antifreeze to the inside going round the inside and outside of the roadbed and a liquid sending pump for sending the water or the antifreeze in the roadbed circulating heat exchange pipe. In the heat storage snow melting system using solar heat, the primary part and the secondary part are separately, respectively and independently controlled, and heat is exchanged between the primary part and the secondary part by a heat exchanger. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a solar heat-based heat storage snow melting system that can acquire, store, and use sufficient natural energy such as geothermal at a low cost and a control method for the solar heat-based heat storage snow melting system.

Conventionally, a non-sprinkling snow melting system that removes snow by circulating hot water heated by a kerosene boiler, a gas water heater, a heat pump, or the like or an antifreeze liquid to a roadbed or the like has been used. Such a non-sprinkling snow melting system has a high snow melting performance and has been well received as a system that can be automatically controlled without requiring manual labor.
In recent years, in order to reduce the running cost while enjoying the convenience of this non-sprinkling snow melting system, various methods for acquiring the heat source have been studied.

As such a non-watering snow melting system, for example, Patent Document 1 discloses a clean energy utilization extinguishing / snow melting method. In this method, geothermal heat is acquired and used by burying inner and outer double concentric tubes vertically from the ground to a depth of 100 to 150 m. According to this method, consumption of fossil fuels such as oil can be suppressed by effectively utilizing a stable underground temperature regardless of the season.

However, with this method, although stable underground temperature can be obtained, the underground temperature is about 10 to 20 ° C. unless it is an eruption area such as a hot spring, so that sufficient thermal energy cannot be obtained. And an auxiliary heat source such as a heat pump may be required. In addition, the use of geothermal power can surely reduce the running cost, but the initial cost is increased by introducing an excavation cost of 100 to 150m underground and an auxiliary heat source. Unless initial costs are reduced with gold, there are situations where the introduction will be slowed down. Furthermore, if too much underground energy is used in the winter season, the temperature in the surrounding area will not recover until the following year, so-called “heat withering” will occur, and it will not be possible to acquire sufficient geothermal heat. In some cases, depending on the heat source, the attractiveness of using clean energy was halved.

On the other hand, Patent Document 2 discloses a solar heat storage snow melting device. This method excavates the ground surface to provide a buried portion having a predetermined depth, forms a heat insulation tank around the buried portion, and pipes a heat-collecting heat radiating pipe meandering vertically in a space surrounded by this In addition, a natural energy utilization system that fills the heat storage member inside to form a heat storage tank, encloses the circulating fluid in the heat collection heat radiating pipe in the heat storage tank and the heat radiation collecting pipe on the surface side, and circulates this circulating liquid in both pipes It is. According to this method, heat can be acquired on the ground surface in which the heat-dissipating heat collecting tube is embedded in summer, and snow can be melted using the heat acquired in summer in winter.

However, in this method, a circulation path in which the buried side and the ground side are connected in series is formed, and when circulating the circulating fluid, the flow rate of the circulating fluid can be adjusted independently on each side. It was not possible, and there were a number of inconveniences because the flow rate had to be equal on each side. That is, this inconvenience is that, in the winter, immediately after the start of the snow melting operation, a stored hot circulating fluid is obtained, but after a while after the snow melting operation is started, the temperature of the circulating fluid decreases. This is due to

For example, immediately after entering the winter season, the underground thermal energy is not yet used, and energy is consumed according to the underground temperature and flow rate. In this case, heat energy may be consumed more than necessary. In order to prevent this waste of heat energy, for example, when the flow rate is controlled, the temperature of the circulating fluid is high on the entrance side of the roadbed in the roadbed, but heat energy is also given to the outside air in addition to snow melting in the roadbed. Deprivation reduces the temperature of the circulating fluid, and when it reaches the exit side of the roadbed, the snowmelting ability is insufficient, and snowmelt “unevenness” may occur on the roadbed.

Also, as the winter season approaches the end, there may be a shortage of thermal energy stored in the ground due to excessive operating loads. For this reason, in order to melt snow in a situation where the temperature in the ground has decreased, it is necessary to run an operation in which a considerably large flow of water or the like is flowed to transmit the heat energy to the ground. However, since the underground heat collecting part and the ground roadbed are usually communicated with each other through a long pipe, the pressure loss in the pipe path increases and the load on the pump increases. That is, an expensive and large pump has to be used in order to flow water or the like at a high flow rate in the presence of a large pressure loss.

Furthermore, as a pipe used for the snow melting system, a SUS pipe or a heat pipe is used from the viewpoint of thermal conductivity or the like. However, in recent years, there has been a problem that the initial cost increases due to the use of these metals while the metal prices are soaring.

Therefore, there has been a demand for a snow melting system that does not require deep excavation and does not require an expensive auxiliary heat source and that can suppress heat energy loss and pressure loss due to circulation operation.
Japanese Patent No. 2808389 Japanese Patent No. 2849699

An object of this invention is to provide the control method of the solar thermal utilization thermal storage snowmelt system which can acquire, store and utilize sufficient natural energy, such as geothermal, at low cost, and a solar thermal utilization thermal storage snowmelt system.

The present invention includes a heat storage tank formed in the ground, a heat storage tank circulation heat exchange pipe that circulates water or antifreeze liquid inside and outside the heat storage tank, and water or antifreeze liquid sent into the heat storage tank circulation heat exchange pipe. A primary part composed of a liquid feed pump for liquefying, a roadbed embedded in the ground surface, a roadbed circulation heat exchange pipe for circulating water or antifreeze liquid inside and outside the roadbed, and the roadbed circulation heat exchange pipe A solar heat storage snow melting system comprising a secondary part comprising a liquid feed pump for delivering water or antifreeze, wherein the primary part and the secondary part are separated and controlled independently of each other. In addition, a heat storage and snow melting system using solar heat, in which heat is exchanged between the primary part and the secondary part by a heat exchanger.
Hereinafter, the present invention will be described in detail.

As a result of intensive studies, the present inventors have determined that a heat storage tank formed in the ground, a heat storage tank circulation heat exchange pipe that circulates water or antifreeze liquid inside and outside the heat storage tank, and the heat storage tank circulation heat exchange pipe A primary part composed of a liquid feed pump for feeding water or antifreeze liquid therein, a roadbed embedded in the ground surface, a roadbed circulation heat exchange pipe for circulating water or antifreeze liquid inside and outside the roadbed, and By forming the secondary part consisting of the liquid feed pump for feeding water or antifreeze liquid into the subbase circulation heat exchange pipe so that it can be separated and controlled independently, each circulation heat can be controlled as necessary. It is possible to control the flow rate of water or antifreeze liquid circulating in the exchange pipe, that is, the heat transfer. It is possible to reduce the. Thus, in winter, snow can be melted by absorbing heat from the heat storage tank and releasing the absorbed heat from the roadbed. In summer, heat is absorbed from the roadbed of roads, parking lots, etc., and the absorbed heat is stored in the heat storage tank in the ground. By carrying it over to winter, it is supplied to the roadbed again in winter and used for snow melting, etc. Can do. As described above, the present inventors have found that natural energy can be efficiently used at low cost, and have completed the present invention.

FIG. 1 is a schematic diagram showing an outline of a solar heat utilization heat storage and snow melting system of the present invention.
In FIG. 1, 1 is a heat storage tank, 2 is a roadbed, 31 is a heat storage tank circulation heat exchange pipe, 32 is a roadbed circulation heat exchange pipe, and 4 is a control unit. The heat storage tank 1 includes a heat shield layer 11 formed in the soil and soil surrounded by the heat shield layer 11. The roadbed 2 is made of concrete 21 formed near the ground surface. The heat storage tank circulation heat exchange pipe 31 circulates inside and outside the heat storage tank 1, and is connected to the heat exchanger 41, the temperature sensor 42, the liquid feed pump 43, and the flow meter 44 in the control unit 4. The roadbed circulation heat exchange pipe 32 circulates inside and outside the roadbed 2 and is connected to the heat exchanger 41, the temperature sensor 42, the liquid feed pump 43, and the flow meter 44 in the control unit 4. The heat storage tank circulation heat exchange pipe 31 and the roadbed circulation heat exchange pipe 32 are separated from each other to form independent circulation paths, and are individually connected to the liquid feed pump 43 and the like in the control unit 4. Therefore, each is controlled independently.
Water or the like is fed into the heat storage tank circulation heat exchange pipe 31 and the roadbed circulation heat exchange pipe 32 by the liquid feed pump 43 in the control unit 4. For example, in winter, when water or the like circulating in the heat storage tank circulation heat exchange pipe 31 passes through the heat storage tank 1, the heat accumulated in the heat storage layer 1 is acquired and the heat exchanger 41 in the control unit 4 is obtained. Then, heat is transferred to the water circulating in the roadbed circulation heat exchange pipe 32. The water or the like circulating in the roadbed circulation heat exchange pipe releases the transmitted heat at the roadbed 2 to melt snow. In the summer, when water or the like circulating in the roadbed circulation heat exchange pipe 32 passes through the roadbed 2, heat is acquired from the roadbed 2 heated by sunlight or the like, and the heat exchanger 41 in the control unit 4 Heat is transferred to the water circulating in the heat storage tank circulation heat exchange pipe 31. The water circulating in the heat storage tank circulation heat exchange pipe 31 releases the transferred heat in the heat storage tank 1 and accumulates heat in the heat storage tank 1 for the winter season.

In the primary part, the heat storage tank is formed in the ground. That is, the soil in the ground plays a role as a heat storage tank. The heat storage tank plays a role of using the geothermal heat of the soil in the ground as a heat source and also plays a role of accumulating solar heat and the like acquired from the roadbed described later.

Conventionally, a heat storage tank is installed on the ground, and a water storage type heat storage tank using a panel tank, a heat storage tank using a latent heat storage material used for Eco Ice (registered trademark), and the like are used. However, there is a problem that such a heat storage tank is expensive to install.
On the other hand, the heat storage tank in the solar heat utilizing snow melting system of the present invention is formed in the ground. Therefore, it can be set as a heat storage tank cheaper than before by utilizing the heat storage property of soil with comparatively low thermal conductivity and high specific heat.

In general, when excavating the ground, it varies depending on the local climate, groundwater level, and the presence or absence of hot springs, but the excavation depth is about 7-10 m and reaches a stable temperature range of about 12-18 ° C per year. To do. Furthermore, when the excavation depth reaches about 100 m, the temperature often starts to rise, but the excavation depth ranges from about 7 to 50 m and reaches a soil layer in a stable temperature zone of about 12 to 18 ° C. per year.

Conventionally, the method for forming the heat storage tank is not particularly limited. For example, the excavation method such as boring is used to excavate a vertical hole (bore hole), insert a heat exchange pipe, and then embed it. It is conceivable to acquire the heat energy inside.
However, in such a case, the deeper the excavation depth, the greater the amount of heat that can be acquired, but the excavation cost increases dramatically. On the other hand, when excavating shallowly, for example, when the excavation depth is about 7 m from the surface layer, the excavation cost is low, but it is affected by the temperature of the ground surface, so there is a problem that the heat energy that can be acquired becomes insufficient. It was.
On the other hand, in the solar heat utilization heat storage and snow melting system of the present invention, as described later, in addition to geothermal heat, solar heat and the like are acquired in the summer, and the acquired solar heat and the like are used in the winter, so that the depth is shallower than before. However, even if a heat storage tank is formed, necessary geothermal heat can be obtained.

It does not specifically limit as a method of forming the said thermal storage tank, For example, it can form by excavating the ground surface and embedding the heat exchange pipe mentioned later.
In the above burial, waste soil, mountain sand, river sand, etc. generated when excavating the ground surface may be backfilled, and in order to increase heat storage performance, materials with higher specific heat, latent heat storage materials, etc. are used. May be.

As for the depth of the excavation, a preferable lower limit of the depth from the ground surface is 0.5 m, and a preferable upper limit is 20 m. If it is less than 0.5 m, a region for providing a heat shield layer to be described later cannot be secured, and sufficient heat storage may not be performed, or sufficient geothermal heat may not be obtained. If it exceeds 20 m, the cut construction cost may increase.
In the above excavation, if the depth is less than about 2 m from the ground surface, the earth retaining is not necessary, but if the depth exceeds 2 m, the earth retaining work is required or the excavation angle needs to be increased. It may become.

As a method for forming the heat storage tank, a method may be used in which a vertical hole (bore hole) is excavated in a group pile type, a heat exchange pipe described later is inserted into the vertical hole, and then the vertical hole is buried. The heat exchange pipe to be inserted is preferably embedded so as to circulate in the borehole.

The preferable lower limit of the depth from the ground surface is 2.0 m, and the preferable upper limit is 100 m. If it is less than 2.0 m, it may not be possible to obtain sufficiently stable geothermal heat. When it exceeds 100 m, the construction work for the vertical hole may be inferior.

As for the space | interval of the said standing holes, a preferable minimum is 0.2 m and a preferable upper limit is 2.5 m. If it is less than 0.2 m, the number of excavation vertical holes for forming a heat storage tank having a predetermined volume increases, which increases the cost, and the number of excavation increases due to thermal interference between adjacent vertical holes. In some cases, a sufficient amount of heat cannot be secured. If it exceeds 2.5 m, the amount of heat accumulated in the ground may not be sufficiently absorbed or radiated by the heat exchange pipe.

The heat storage tank is preferably provided with a heat shielding layer on the upper surface, the side surface, and the lower surface. That is, it is preferable that the heat storage tank is surrounded by a heat shield layer.
By installing the heat shielding layer, it is possible to prevent heat from escaping from the heat storage tank and to improve the heat storage property. Therefore, even if the excavation volume for forming the heat storage tank is reduced, sufficient heat can be secured, and excavation costs and the like can be suppressed.

It does not specifically limit as a raw material which comprises the said heat insulation layer, For example, a foamed polyethylene, a phenol foam, a phenol urethane foam, a urethane foam, a polystyrene foam, a foamed polycarbonate, a foamed polypropylene, a polyisocyanate foam etc. are mentioned.

The preferable lower limit of the thickness of the heat shield layer is 10 mm, and the preferable upper limit is 500 mm. If it is less than 10 mm, sufficient heat insulation may not be obtained. When it exceeds 500 mm, workability may be inferior. A more preferable lower limit is 30 mm, and a more preferable upper limit is 100 mm.

In the secondary part, the roadbed is embedded in the ground surface.
The roadbed can be used as a heat collecting unit for acquiring solar heat in summer and can be used as a heat radiating unit in winter. That is, in the summer, the solar heat absorbed by the roadbed is obtained by water circulating in the roadbed circulation heat exchange pipe laid in the roadbed, and the heat obtained through the heat exchanger is underground. The heat can be released and stored in the heat storage tank. On the other hand, in winter, the water or antifreeze circulated in the heat storage tank circulation heat exchange pipe acquires geothermal heat when passing through the heat storage tank, and the geothermal heat acquired in the roadbed via the heat exchanger. By discharging, it can be used for melting snow on the roadbed.

The method for forming the above-mentioned roadbed is not particularly limited, for example, laying a quarry stone or the like when excavating the ground shallowly, temporarily placing a heat exchange pipe (to be described later) thereon, pouring concrete etc. from above, Furthermore, the method etc. which perform asphalt pavement etc. on concrete are mentioned.

In the primary part, the heat storage tank circulation heat exchange pipe circulates inside or outside the heat storage tank and circulates water or antifreeze liquid inside.
In the secondary part, the roadbed circulation heat exchange pipe circulates inside and outside the roadbed and circulates water or antifreeze liquid inside.

The antifreeze is not particularly limited, and examples thereof include those obtained by diluting ethylene glycol, propylene glycol or the like as a main component with water and adding a rust inhibitor or the like.

It does not specifically limit as a heat exchange pipe which comprises the said thermal storage tank circulation heat exchange pipe and the said roadbed circulation heat exchange pipe, For example, a PE pipe, a bridge | crosslinking PE pipe, a SUS pipe, a copper pipe, a metal composite pipe etc. are mentioned. Among these, a metal composite tube is preferable.

The metal composite tube includes a synthetic resin layer provided on the outermost layer, a metal layer provided on the inner surface side of the synthetic resin composition layer, and a synthetic resin layer provided on the inner surface side of the metal layer. It is preferable.

As a heat exchange pipe, it is indispensable to form a joint when a long flow path of water or antifreeze circulating inside is secured or bent. As conventional heat exchange pipes, metal tubes with excellent heat exchange efficiency have been used, but in this case, not only the labor and cost during construction will be increased, but there is a possibility that leakage will occur as many as the number of joints. is there. Furthermore, there is a risk that corrosion is unavoidable due to the fluid flowing inside the heat exchange pipe, the soil quality and the moisture in the soil that are in contact with the outside of the heat exchange pipe. Therefore, in recent years, synthetic resin pipes excellent in corrosion resistance and flexibility have been used instead of metal pipes. However, since the synthetic resin pipe is largely lacking in heat exchange capacity compared to the metal pipe, there are problems that it takes time and the temperature does not increase when collecting and using heat.
On the other hand, when the metal composite pipe is used, in addition to exhibiting heat transfer performance comparable to that of the metal pipe, it can overcome the corrosiveness that has been a drawback of the metal pipe. it can. Moreover, since the said metal composite pipe can be bent and a long piping can be manufactured, a joint can be decreased and long-term durability is also greatly exceeded compared with a metal pipe. Furthermore, since the metal composite tube is excellent in shape retention, the workability is dramatically improved.

In the metal composite tube, the thermal emissivity of the synthetic resin layer provided in the outermost layer or the innermost layer is 0.80 W / m · K or more and the thermal conductivity is 0.50 W / m · K or more. preferable. By setting it as such a structure, higher heat-transfer performance can be exhibited and the running cost of the natural heat hybrid soil heat storage system of this invention can be reduced. When the thermal emissivity is less than 0.80 W / m · K or the thermal conductivity is less than 0.50 W / m · K, it may not be possible to efficiently collect a sufficient amount of heat.

The preferable lower limit of the inner diameter of the heat exchange pipe is 5 mm, and the preferable upper limit is 30 mm. If it is less than 5 mm, sufficient thermal energy may not be obtained / released. When it exceeds 30 mm, workability may be inferior.

The shape of the heat exchange pipe is not particularly limited, but preferably has a meandering shape in the heat storage tank and the roadbed. By having a meandering shape, it is possible to efficiently acquire and release heat.

When the heat exchange pipe has the meandering shape, the meandering pitch has a preferable lower limit of 50 mm and a preferable upper limit of 2500 mm. If it is less than 50 mm, it may be difficult to bend the heat exchange pipe. In addition, because the pitch is too short, heat is absorbed and dissipated near the entrance to the roadbed, but near the outlet from the middle floor, the temperature of the water, etc. that passes through the heat exchange pipe approaches the roadbed temperature. It cannot absorb or dissipate heat. For example, in winter, snow can be melted in the vicinity of the entrance to the roadbed, but snow cannot be melted in the vicinity of the exit from the middle of the roadbed, and snow may accumulate. In order to avoid such problems, this problem can be solved by branching a large number of heat exchange pipes and increasing the number of inlets and outlets to the roadbed. The number of connection points increases, and joint costs and construction work may occur. If it exceeds 2500 mm, heat cannot be absorbed or dissipated in the portion between the heat exchange pipe pitches. For example, in summer, heat cannot be sufficiently obtained from the entire roadbed, and in winter, heat exchange pipes are not obtained. Snow between the pitches may not melt and uneven snow melting may occur.

The primary part and the secondary part each independently have a liquid feed pump for feeding water or antifreeze liquid into the heat storage tank circulation heat exchange pipe and the roadbed circulation heat exchange pipe.
The liquid feed pump plays a role of feeding water or antifreeze into the heat storage tank circulation heat exchange pipe and the roadbed circulation heat exchange pipe.
By having such a structure, it is possible to independently adjust the flow rate of water or the like circulating through the heat storage tank circulation heat exchange pipe and the roadbed circulation heat exchange pipe, so that the heat accumulation tank accumulates in the heat storage tank or the like. It is possible to avoid wasteful consumption of the amount of heat generated and the occurrence of uneven snow melting in the roadbed and reduce pressure loss.

The primary part and the secondary part are separated and controlled independently, and heat is exchanged between the primary part and the secondary part by a heat exchanger.
By having such a structure, water circulated in the heat storage tank circulation heat exchange pipe in the primary part through the heat exchanger, and water circulated in the roadbed circulation heat exchange pipe in the secondary part. And the like can exchange heat. Specifically, for example, in winter, the water or antifreeze liquid circulating in the heat storage tank circulation heat exchange pipe of the primary part acquires geothermal heat when passing through the heat storage tank, and the above-mentioned secondary part is obtained by the heat exchanger. Snow is melted by transferring heat to water or antifreeze that circulates in the subbase circulation heat exchange pipe and releasing heat in the subbase. On the other hand, in the summer, the water or antifreeze circulating in the secondary subbase circulation heat exchange pipe acquires solar heat when passing through the subbase, and the primary heat storage tank circulation heat exchange pipe is obtained by the heat exchanger. Heat is stored in the heat storage tank by transferring heat to the water or antifreeze circulating inside and releasing the heat in the heat storage tank. Thus, natural energy can be used efficiently.

Although it does not specifically limit as said heat exchanger, A conventionally well-known thing can be used, but since it is excellent in heat exchange efficiency, it is preferable that it is a countercurrent type.

The solar heat utilization heat storage and snow melting system of the present invention preferably has a control unit.
The control unit plays a role of circulating water or antifreeze liquid in the heat storage tank circulation heat exchange pipe and the roadbed circulation heat exchange pipe by automatic control operation. In the control unit, the heat storage tank circulation heat exchange pipe and the roadbed circulation heat exchange pipe are independently connected to the liquid feed pump and the like, thereby the inside of the heat storage tank circulation heat exchange pipe and the roadbed circulation heat exchange pipe. Water or antifreeze can be circulated inside each independently.

The control unit is not particularly limited as long as it can adjust the flow rate according to the load during snow melting, heat storage, etc., and circulate water or antifreeze liquid in the heat exchange pipe. Is used.

In the control unit, it is preferable that the heat storage tank circulation heat exchange pipe and the roadbed circulation heat exchange pipe independently have various sensors such as a temperature sensor and a snowfall sensor. The temperature sensor plays a role of measuring the temperature of water or antifreeze flowing through each circulation path. The snowfall sensor plays a role of detecting the presence or absence of snowfall.

Conventionally, when a temperature sensor is embedded in a roadbed or a heat storage tank, there is a risk of occurrence of disconnection or the like due to aged deterioration or the like. On the other hand, in the solar heat utilizing snow melting system of the present invention, the control unit has a temperature sensor or the like, thereby avoiding the risk of occurrence of disconnection or the like. The temperature sensor or the like is not embedded in the heat storage tank or the roadbed, but is installed in the control unit, so that the temperature circulating in the heat exchange pipe can be easily confirmed. It is possible to smoothly determine whether to start the heat storage operation or the snow melting operation in winter.

In the control unit, it is preferable that the heat storage tank circulation heat exchange pipe and the roadbed circulation heat exchange pipe each independently have a flow meter.
The flow meter plays a role of measuring the flow rate of water or antifreeze flowing through each circulation path.
The control unit may further include a throttle valve or an inverter control device.

Although it does not specifically limit as a method of operating the solar heat utilization thermal storage snow melting system of this invention, Automatic operation is preferable and it is preferable to change a driving | running aspect according to a season etc.

As a result of measuring the outside air temperature and the precipitation amount in the summer, for example, when the outside air temperature is 30 ° C. or more and the precipitation amount is 0 mm, the solar heat utilization heat storage and snow melting system of the present invention is capable of generating heat such as solar heat on the roadbed. The acquired heat can be stored in the heat storage tank via the heat exchanger.
The outside air temperature and the precipitation amount for judging the operation can be changed on the control in consideration of the region and the actual driving situation. Alternatively, the determination may be made based only on the outside air temperature, or the temperature sensor may be actually buried in the roadbed, and the following heat storage determination operation start determination may be made based on the measured temperature value.
In the heat storage judgment operation, first, in the secondary part, the feed pump of the roadbed circulation heat exchange pipe is rotated, water is circulated in the roadbed circulation heat exchange pipe, and the return temperature of the water etc. in the roadbed circulation heat exchange pipe ( T2) is measured and the liquid feed pump is stopped. Next, the liquid feed pump of the heat storage tank circulation heat exchange pipe in the primary part is rotated to circulate the water in the heat storage tank circulation heat exchange pipe, and the return temperature (T1) of the water in the heat storage tank circulation heat exchange pipe is measured. And stop the pump.
The measured T2 and T1 are compared to determine whether or not to perform the heat storage operation. When T2 is higher, rotate the liquid feed pump of the heat storage tank circulation heat exchange pipe of the primary part and the liquid feed pump of the road bed circulation heat exchange pipe of the secondary part, and the heat acquired by the roadbed is By transmitting to the heat storage tank via the heat exchanger, the heat acquired by the roadbed is accumulated in the heat storage tank.
Since heat storage is performed after performing the heat storage determination operation in this way, heat can be reliably conveyed from the roadbed side to the ground. Further, since the heat storage determination operation is performed separately for the primary side and the secondary side, the heat accumulated in the heat storage tank by the heat storage determination operation is not transmitted to the roadbed side.
On the other hand, as a result of measuring the outside air temperature and the precipitation amount, for example, when the outside air temperature is 30 ° C. or more and the condition of the precipitation amount of 0 mm is not satisfied, a stop operation for stopping the liquid feeding pump is performed.
The stop operation is also executed when it is determined that T2 being measured during heat storage is lower than T1 and heat storage is not performed.
Furthermore, in order to avoid frequent operation | movement, the solar-heat-use heat storage snow-melting system of this invention measures an external temperature and precipitation every hour, for example after sleeping the said liquid feeding pump on a timer. Thus, after measuring the outdoor temperature and precipitation regularly and automatically, it is determined whether to perform the heat storage operation or to perform timer sleep. This timer time can also be changed in the control.
In the present specification, such an operation mode of the solar heat utilization heat storage snow melting system of the present invention in summer is also referred to as heat storage operation.

In the winter, the solar heat storage heat storage and snow melting system of the present invention, in the winter season, when detecting snow using a conventionally known snowfall sensor, the primary part of the heat storage tank circulation heat exchange pipe feed pump, and the secondary roadbed circulation Rotate the pump of the heat exchange pipe at full power and continue the circulation operation. Calculate the heat energy consumption on the circulating heat exchange pipe side.
According to the obtained heat energy consumption, the flow rate of the water etc. which circulates in the heat storage tank circulation heat exchange pipe of a primary part is adjusted. That is, for example, when the heat energy consumption is small (in the case of a low snow melting load), the primary part is changed to the secondary part by decreasing the number of revolutions of the liquid feed pump of the heat storage tank circulation heat exchange pipe of the primary part. Reduce the amount of heat supplied.
On the other hand, when there is no snowfall, the liquid feed pump is stopped. In order to avoid frequent operation, after the liquid feeding pump sleeps on the timer, for example, every 30 minutes, the presence or absence of snow is detected using a snow melting sensor. In this way, it is determined whether or not snow melting operation or timer sleep is performed after detecting the presence or absence of snow periodically and automatically.
In the present specification, such an operation mode of the solar heat utilization heat storage snow melting system of the present invention in winter is also referred to as snow melting operation.

In the snow melting operation using the solar heat storage thermal snow melting system of the present invention, the liquid feed pump of the roadbed circulation heat exchange pipe in the secondary part rotates at full power, whereas the heat storage tank circulation heat in the primary part rotates. Since the liquid feed pump of the exchange pipe has only to be rotated according to the required amount of heat, only the necessary amount of heat can be supplied.
Further, the primary part heat storage tank circulation heat exchange pipe and the secondary part subbase circulation heat exchange pipe do not communicate with each other, and are independent circulation paths, so that pressure loss is suppressed, Since it is possible to secure a sufficient flow rate of water or the like that circulates in the next subbase circulation heat exchange pipe, it is possible to suppress the occurrence of uneven snowmelt without causing unevenness in the temperature distribution of the subbase. .
As the liquid feeding pump, a conventionally known pump whose flow rate is variable in the range of 0 to 100 L / min can be used.
The flow rate setting for controlling the liquid feeding pump is preferably 0 to 30 L / min, more preferably about 0 to 20 L / min, although it depends on the snow melting area.
The numerical value of the full power operation in the control of the liquid feed pump is variable in the control, but the preferable lower limit is 10 L / min, and the preferable upper limit is 20 L / min. If the flow rate is low during full operation of the above-mentioned liquid feed pump, the water circulating in the circulating heat exchange pipe in both the primary part and the secondary part will slow to change, and it will take time to judge the temperature on the return side of the control unit. May be necessary, and the amount of heat carried through the circulating water may be limited. On the other hand, if the flow rate is too large, the pump to be used becomes large, which may cause problems such as initial cost, installation space, and increased power consumption. A more preferable lower limit is 10 L / min, and a more preferable upper limit is 15 L / min.

By using the solar heat utilization heat storage and snow melting system of the present invention, the amount of heat consumed in the roadbed is calculated while keeping the flow rate of the roadbed circulation heat exchange pipe constant at a high level during winter snowfall, and heat is stored according to the amount of heat. The flow rate of water circulating in the tank circulation heat exchange pipe can be varied. In this way, it is possible to always supply an appropriate amount of energy without waste while suppressing the occurrence of uneven snow melting on the roadbed.
This is a method for controlling the solar heat storage heat melting snow system of the present invention, calculating the amount of heat consumed in the roadbed while maintaining a constant flow rate of water or antifreeze liquid circulating in the roadbed circulation heat exchange pipe, A control method for a solar heat storage heat melting snow system that varies the flow rate of water or antifreeze liquid circulating in the heat storage tank circulation heat exchange pipe according to the amount of heat is also one aspect of the present invention.

The control method of the solar heat storage heat melting snow system according to the present invention operates the liquid feed pump in one of the heat storage tank circulation heat exchange pipe or the roadbed circulation heat exchange pipe when the solar heat utilization heat storage snow melting system is started. The temperature of the water or antifreeze liquid circulating in the circulating heat exchange pipe is confirmed by the temperature sensor, the liquid feeding pump is stopped, and the liquid feeding pump is operated in the other circulating heat exchange pipe. After confirming the temperature of the water or antifreeze circulating in the circulating heat exchange pipe and stopping the liquid feed pump, the temperature of the water or antifreeze circulating in the heat storage tank circulating heat exchange pipe is the temperature of the roadbed circulating heat exchange pipe When the temperature of the water or antifreeze circulating in the interior is higher than that, the snow melting operation is started, and the temperature of the water or antifreeze circulating in the roadbed circulation heat exchange pipe is increased. It is preferred that when serial higher than the temperature of the water or antifreeze that circulates heat storage tank circulating heat exchange pipe starts thermal storage operation. By controlling by such a method, the solar heat utilization heat storage snow melting system of this invention can be controlled efficiently according to a season etc.

ADVANTAGE OF THE INVENTION According to this invention, the control method of the solar-heat-use thermal storage snowmelt system which can acquire, store and utilize sufficient natural energy, such as sufficient geothermal at low cost, and the control method of a solar-heat-use thermal storage snowmelt system can be provided.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

Example 1
(Heat storage tank)
At the snow melting test site in Myoko City, Niigata Prefecture, the ground was excavated to be 7.28 m long, 2.18 m deep, and 112.9 m ³ in volume, and a metal composite pipe with an inner diameter of 20 mm (Eslon Super Eslometax, Sekisui Chemical Co., Ltd.) was embedded in the interior at a pitch of about 500 mm, and the periphery was covered with a polystyrene foam having a thickness of 500 mm. Furthermore, in order to prevent rainwater from entering, the heat storage tank was formed by covering the periphery of the polystyrene foam with a 5 mm-thick butyl rubber sheet.
The upper surface of the heat storage tank was formed in the ground at a depth of about 500 mm from the ground surface.

(Roadbed)
Concrete was cast with a thickness of 100 mm, and at that time, a crosslinked PE pipe having an inner diameter of 13 mm was buried at a depth of 30 mm from the ground surface so that the pitch was 75 mm. After curing the concrete, a 20 mm thick asphalt was laid on the concrete so that the crosslinked PE pipe was buried at a depth of 50 mm from the ground surface.

(Heat exchanger, etc.)
The primary part heat storage tank circulation heat exchange pipe and the secondary part roadbed circulation heat exchange pipe are water circulated in each circulation heat exchange pipe via a copper plate heat exchanger (CB26-18H, manufactured by Alfa Laval). Etc., so that heat can be exchanged, and each is connected independently to a DC pump (PD-21, manufactured by Three Phase Electric Co., Ltd.) to circulate in the heat storage tank circulation heat exchange pipe and the roadbed circulation heat exchange pipe. A control unit capable of independently controlling the flow rate of water and the like was installed.

FIG. 1 is a schematic diagram showing an outline of a solar heat utilization heat storage and snow melting system produced.
In FIG. 1, 1 is a heat storage tank, 2 is a roadbed, 31 is a heat storage tank circulation heat exchange pipe, 32 is a roadbed circulation heat exchange pipe, and 4 is a control unit. The heat storage tank 1 includes a heat shield layer 11 formed in the soil and soil surrounded by the heat shield layer 11. The roadbed 2 is made of concrete 21 formed near the ground surface. The heat storage tank circulation heat exchange pipe 31 circulates inside and outside the heat storage tank 1, and is connected to the heat exchanger 41, the temperature sensor 42, the liquid feed pump 43, and the flow meter 44 in the control unit 4. The roadbed circulation heat exchange pipe 32 circulates inside and outside the roadbed 2 and is connected to the heat exchanger 41, the temperature sensor 42, the liquid feed pump 43, and the flow meter 44 in the control unit 4. The heat storage tank circulation heat exchange pipe 31 and the roadbed circulation heat exchange pipe 32 are separated from each other to form independent circulation paths, and are individually connected to the liquid feed pump 43 and the like in the control unit 4. Therefore, each is controlled independently.

In the summer, the solar heat storage snow melting system obtained in Example 1 warms the secondary roadbed by solar heat, and when the temperature of the roadbed becomes higher than the temperature in the primary heat storage tank, Then, heat is transferred from the roadbed to the heat storage tank via the heat exchanger of the control unit, and stored in the heat storage tank. Thus, in summer, it was confirmed that the maximum temperature in the heat storage tank was 35.9 ° C. After that, the heat in the heat storage tank was carried over in the fall, and it was confirmed that the temperature in the heat storage tank just before the start of snow melting operation in the winter was maintained at 30.2 ° C.

During snowfall in winter, the flow rate of each circulation path is usually about 1 L / min, but the total flow rate of the secondary subbase circulation heat exchange pipe is 15 L / min (since it is a three-division circuit, The supply amount of about 5 L / min) was confirmed to eliminate the uneven snow melting on the roadbed. Further, by controlling the flow rate of the heat storage tank circulation heat exchange pipe in the primary part, a heat amount of about 120 W / m ² was supplied at the maximum output as required. When the snow melting load was small, the supply of heat was reduced to about 30 W / m ² . In this way, it was confirmed that the amount of heat was supplied without excess and deficiency and that the snow melting during the winter was completed without the amount of heat in the heat storage tank being insufficient.

Furthermore, since the solar heat-based heat storage and snow melting system obtained in Example 1 is not exposed to the outside, such as a temperature sensor, the sensor line may not be damaged, and the sensor line may not be deteriorated. confirmed.
As described above, it was confirmed that the solar heat-use heat storage and snow melting system of the present invention can be operated all year round by automatic operation.
The total operation time of snowmelt in winter was 285 hours, and the power consumption mainly for the control system and two DC pumps was 34.2 kWh. Assuming 21 yen per kWh, the winter snow melting cost was 718.2 yen.

(Comparative Example 1)
As shown in FIG. 2, a model of the snow melting system having the same structure as that of Example 1 was reproduced on the simulation except that the primary part and the secondary part were directly passed through the control unit.
In this snow melting system, since the primary part and the secondary part cannot be operated separately during the heat storage operation, the heat storage operation is performed if the conditions of the outside air temperature and the rainfall amount are satisfied.
As a result, in the autumn season, although the outside air temperature is 30 ° C. or higher, the heat storage operation is performed even when the refrigerant temperature in the roadbed and the heat exchange pipe in the road bed is low, so in fact it is a heat dissipation operation. Oops. That is, in summer, the maximum temperature in the heat storage tank reached 35.9 ° C. as in the first embodiment, but after that, the temperature in the heat storage tank decreased greatly in autumn and the temperature in the heat storage tank immediately before the start of snow melting operation in winter was 25. The temperature was 1 ° C., which was 5.1 ° C. lower than Example 1.

Further, since individual operation on each side is not possible in the winter snow melting operation, the total flow rate of the circulation path of the entire circuit is set to 3 L / min (because it is a three-division circuit, 1 L / min is supplied to each circuit). As a result, although snow can be melted near the roadbed entrance, heat did not remain from the middle to the second half of the roadbed, and the snow did not melt, resulting in uneven snowmelt. Furthermore, the amount of heat supplied was high in the heat storage tank at the beginning of the winter, but as the operation time was extended, the temperature in the heat storage tank decreased, and the snow melting ability could not be exhibited when 100 hours had passed. It was. In the first place, since the temperature in the heat storage tank was low, the amount of heat in the heat storage tank was insufficient, and snow melting during the winter could not be completed.

(Comparative Example 2)
As shown in FIG. 3, a model of a snow melting system using a gas boiler was reproduced on a simulation. In FIG. 3, 5 indicates a gas boiler.
In the winter snow melting operation, an output capable of exhibiting approximately 130 W / m ² was set. In the analysis, snow melting unevenness did not occur and the snow melting during the winter season was completed.
However, the total operating time for snow melting during the winter was 285 hours, and the amount of gas used was about 192 m ³ including the loss of roadbed and equipment. The electricity cost for the control system was excluded from the cost, and a simulation using city gas was performed.
When 120 yen per gas 1 m ^3, winter snow melting cost became very expensive and ¥ 23040.

ADVANTAGE OF THE INVENTION According to this invention, the control method of the solar-heat-use thermal storage snowmelt system which can acquire, store and utilize sufficient natural energy, such as sufficient geothermal at low cost, and the control method of a solar-heat-use thermal storage snowmelt system can be provided.

It is a schematic diagram which shows an example of the solar heat utilization thermal storage snow melting system of this invention. It is a schematic diagram which shows an example of the snow melting system used in the comparative example 1. It is a schematic diagram which shows an example of the snow melting system used in the comparative example 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat storage tank 11 Heat insulation layer 2 Roadbed 21 Concrete 30 Heat exchange pipe 31 Heat storage tank circulation heat exchange pipe 32 Roadbed circulation heat exchange pipe 4 Control unit 41 Heat exchanger 42 Temperature sensor 43 Liquid feed pump 44 Flow meter 5 Gas boiler

Claims (3)

A heat storage tank formed in the ground, a heat storage tank circulation heat exchange pipe for circulating water or antifreeze liquid inside and outside the heat storage tank, and water or antifreeze liquid for sending water or antifreeze liquid into the heat storage tank circulation heat exchange pipe A primary part composed of a liquid feed pump, a roadbed embedded in the ground surface, a roadbed circulation heat exchange pipe for circulating water or antifreeze inside and outside the roadbed, and water or antifreeze liquid in the roadbed circulation heat exchange pipe A solar heat storage heat-smelting snow system comprising a secondary part comprising a liquid feed pump for delivering liquid,
The primary part and the secondary part are separated and controlled independently of each other, and heat exchange is performed between the primary part and the secondary part by a heat exchanger. Solar thermal storage heat melting snow system. A method for controlling a solar heat storage and melting snow system according to claim 1,
While maintaining a constant flow rate of water or antifreeze circulating in the roadbed circulation heat exchange pipe, the amount of heat consumed in the roadbed is calculated, and water or antifreeze liquid circulated in the heat storage tank circulation heat exchange pipe according to the heat quantity The control method of the solar thermal storage heat-melting snow system characterized by varying the flow rate of the solar heat. At the start of the solar thermal heat storage snow melting system, one of the heat storage tank circulation heat exchange pipe or the roadbed circulation heat exchange pipe operates the liquid feed pump and circulates in the circulation heat exchange pipe by the temperature sensor. Check the temperature of the water or antifreeze liquid to be stopped, stop the liquid feed pump,
Further, in the other circulating heat exchange pipe, the liquid feed pump is operated, the temperature of the water or antifreeze liquid circulating in the circulating heat exchange pipe is confirmed by the temperature sensor, and after the liquid feed pump is stopped,
If the temperature of the water or antifreeze circulating in the heat storage tank circulation heat exchange pipe is higher than the temperature of the water or antifreeze circulating in the roadbed circulation heat exchange pipe, start the snow melting operation,
The heat storage operation is started when the temperature of water or antifreeze circulating in the roadbed circulation heat exchange pipe is higher than the temperature of water or antifreeze circulating in the heat storage tank circulation heat exchange pipe. The control method of the solar heat utilization thermal storage snow melting system of 2 description.

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