JP3928085B2 - Non-watering snow melting system and method of operating the system - Google Patents

Description

  The present invention relates to a non-watering snow melting system and a method for operating the system. More specifically, the present invention relates to a non-sprinkling snow melting system that melts snow by circulating a heat medium in a pipe laid in a snow melting area and an operation method of the system. In the present specification, the “snow melting area” refers to an area or a range in which snow is to be melted, such as the vicinity of the entrance of a building, a parking lot, and a sidewalk.

Conventionally, in cold regions, various snow melting systems have been adopted mainly to prevent traffic obstacles due to snow accumulation. Some solar heat is stored in the ground, and the stored heat is put on a heat medium and supplied to a pipe laid in a snow melting area (see, for example, Patent Document 1).
In the system described in Patent Document 1, a buried portion having a predetermined depth is provided by excavating the ground surface, a heat insulating layer is formed around the buried portion, and a space surrounded by the heat insulating layer is made of stainless steel. A heat collecting pipe formed of a pipe is piped and the space is filled with a heat storage member. In addition, a heat collecting tube connected to the heat collecting tube is laid in the snow melting area, and the circulating fluid is sealed in the heat collecting tube and the heat collecting tube, and the circulating fluid passes from the heat collecting tube through the heat collecting tube to the heat collecting tube. A pump device is provided to circulate back again.

JP-A-7-279114 (FIG. 1)

  However, the system described in Patent Document 1 has a problem that heat efficiency is poor because the heat stored in the heat storage member is transmitted to the circulating fluid through the heat collection pipe. In addition, as a part for storing heat, a heat insulating layer is formed on the bottom and wall of a recess formed by excavating the ground surface, and then a heat collecting pipe and a heat storage member are provided in the recess, which increases the installation cost. There is.

  The present invention has been made to solve such a problem, and while improving the utilization efficiency of the stored heat, it is possible to simplify the structure and reduce the installation cost, and a non-sprinkling snow melting system of the system. The purpose is to provide driving methods.

The non-sprinkling snow melting system of the present invention is a heat-absorbing and radiating pipe laid in a snow melting area, in which a heat medium flows, and an existing septic tank buried in the ground for wastewater treatment, and stores the heat medium A septic tank that can be used, a heat medium in the septic tank, and a pump unit that returns the heat medium from the outlet part of the heat radiating and radiating pipe to the septic tank, and is stored in the septic tank. And a heat insulating material layer covering the surface of the heat medium .

  The pump section is disposed in a feed pipe that connects the inlet portion of the heat absorbing and radiating pipe and the inside of the septic tank, a return pipe that connects an outlet portion of the heat absorbing and radiating pipe and the inside of the septic tank, and a pipe line of the feed pipe The circulation pump can be configured.

  In the present invention, since the heat medium (water, brine, etc.) stored in the septic tank is directly circulated in the heat absorbing / dissipating pipe with a pump, the heat of the heat medium can be used efficiently.

  Moreover, in this invention, the septic tank is utilized as a means to store a heat medium. This septic tank has been conventionally used to discharge human waste and household wastewater discharged from households and small-scale establishments in areas where sewerage is not established, and then discharge them to rivers and the like after contact aeration. However, in recent years, public sewers and agricultural village drainage facilities have been actively developed from the viewpoint of water quality environmental conservation. Along with this, it is considered that the existing septic tank will be dismantled or disposed of in the future, and a large amount of large-scale industrial waste will be generated. However, the present invention reuses such a septic tank as a heat medium storage means. The cost for constructing can be kept low, and the generation of industrial waste can be eliminated, contributing to environmental conservation.

  In addition, shallow geothermal heat that has not been used effectively so far (geothermal heat from the surface to a depth of about 3m) is used together with solar heat, coupled with the simplicity of the system structure. Maintenance costs can be greatly reduced. Thus, the initial cost and the running cost have been greatly reduced, so that it is possible to widely disseminate a snow melting system for individuals in a warm snowy area, which has been delayed in cost in comparison with the past.

In the present invention, there is provided a heat insulating material layer covering the surface of the heat transfer medium stored in said septic tank. Thereby, heat escape from the heat medium to the ground surface, or conversely, heat from flowing from the ground surface to the heat medium can be suppressed, and the utilization efficiency of the shallow underground heat can be increased.
Moreover, it is preferable to further comprise a temperature sensor provided in the snow melting area, and a control means for controlling the supply of the heat medium to the heat absorbing / dissipating pipe based on a signal from the temperature sensor.
Furthermore, the operation method of the non-sprinkling snow melting system of the present invention is an existing heat-dissipating pipe laid in a snow melting area, in which a heat medium flows, and an existing septic tank buried in the ground for wastewater treatment , A septic tank that can store the heat medium, a pump unit that sends the heat medium in the septic tank to the inlet part of the heat absorbing and radiating pipe, and returning the heat medium from the outlet part of the heat absorbing and radiating pipe into the septic tank, A temperature sensor provided in the snow melting area, a control means for controlling the supply of the heat medium to the heat absorbing and radiating pipe based on a signal from the temperature sensor, and a surface of the heat medium stored in the septic tank An operation method of a non-watering snow melting system comprising a heat insulating material layer ,
When the temperature detected by the temperature sensor is equal to or lower than a first temperature that is lower than the ground temperature and higher than the freezing point, the snow-melting operation is performed to raise the temperature of the snow-melting area by sending the heat medium to the heat absorbing and radiating pipe. When the temperature reaches a second temperature lower than the ground temperature and higher than the first temperature, the snow melting operation is stopped, and when the temperature is equal to or higher than the third temperature higher than the ground temperature. The cooling medium is sent to the heat-absorbing and radiating pipe to lower the temperature of the snow melting area, and the cooling operation is stopped when the temperature reaches a fourth temperature that is higher than the ground temperature and lower than the third temperature. It is characterized by doing.
Thus, by performing the cooling operation in addition to the snow melting operation, it is possible to suppress the temperature rise of the snow melting area in summer and the like, and to make the snow melting area and its surrounding environment comfortable, and even in the winter season, The efficiency of snow melting can be increased by using the heat stored in the snow melting operation.

In the non-sprinkling snow melting system of the present invention, the heat medium in the septic tank is directly sent to the heat absorbing and radiating pipe, so that the heat of the heat medium can be used efficiently and the existing septic tank can be reused as the heat medium storage means. Since it is used, the initial cost can be reduced. In addition, it uses shallow geothermal heat, which has not been used effectively so far, and can be combined with the simple structure of the system, so that the maintenance cost can be extremely reduced.
Further, the operation method of the non-sprinkling snow melting system of the present invention can cool the snow melting area in the summer by using both the snow melting operation and the cooling operation, and also the heat accumulated during the day can be melted in the winter. Can be used.

Hereinafter, based on an accompanying drawing, an embodiment of a non-watering snow melting system (henceforth a system) and its operating method of the present invention are described in detail.
FIG. 1 is an overall explanatory view of an embodiment of the system of the present invention. This system S is used to melt snow near the entrance of a private house and a parking lot. The system S includes a heat absorbing / dissipating pipe 1 laid in a snow melting area E, a septic tank 2 embedded in the site of the house, and a pump unit 3 for circulating a heat medium M in the heat absorbing / dissipating pipe 1. ing.

  The heat absorbing and radiating pipe 1 has a heat medium M such as water or brine flowing through it, and can be made of a synthetic resin such as polyethylene or Teflon (trade name: polytetrafluoroethylene manufactured by DuPont). The size of the heat absorbing / dissipating pipe 1 is not particularly limited in the present invention, and can be appropriately selected according to the laying pitch of the heat absorbing / dissipating pipe 1, the flow rate of the heating medium M, etc. (Inner diameter) can be used. Further, the laying pitch is also appropriately selected according to conditions such as the amount of snow and the temperature of the heating medium M, but is usually about 10 to 20 cm. From the viewpoint of cost, ease of handling, corrosion resistance, and workability, it is preferable to use a synthetic resin pipe such as polyethylene as the heat-absorbing and radiating pipe 1, but from the point that a large thermal conductivity can be obtained, such as stainless steel. A metal pipe may be used.

  The heat absorbing / dissipating pipe 1 is laid in a desired pattern in the snow melting area E as shown in FIGS. The laying pattern in the present embodiment is a zigzag shape, but other laying patterns such as a spiral shape may be adopted depending on the shape of the snow melting area E. The heat absorbing / dissipating pipe 1 is usually laid at a depth of about 3 to 8 cm from the ground surface, and the laying can be performed, for example, as follows. That is, first, the snow melting area E is excavated to a depth of 10 to 20 cm, and the primary concrete 9 having a thickness of about 5 to 10 cm is placed on the entire excavated portion. The reinforcing mesh 10 is laid on the primary concrete 9, and the heat absorbing / dissipating pipe 1 is arranged in a predetermined pattern on the reinforcing mesh 10. Next, the heat absorbing and radiating pipe 1 can be laid by placing a secondary concrete 11 having a thickness of about 5 to 10 cm from above and curing it for a predetermined period.

As the septic tank 2, an existing septic tank that is no longer needed can be reused. In this case, it is not necessary to construct a new facility for storing the heat medium M, so the initial cost of the system S can be reduced. It can be greatly reduced. Many of the existing septic tanks are made of FRP or concrete, and their capacity is generally about 4 m ^{2 for a} 5-person tank and about 8 m ^{2 for} a 10-person tank. If there is such a capacity, it is possible to sufficiently melt snow in the vicinity of the entrance of the house where the septic tank is installed and in the parking lot. In use, it is preferable to remove members such as the filter medium and contact material in the septic tank and wash the inside of the septic tank.

  In the septic tank 2, a circulation pump 4 comprising a submersible pump is provided, and the heat medium M stored in the septic tank 2 is taken out from the septic tank 2 by the circulation pump 4 and laid in the snow melting area E. After passing through the heat absorbing / dissipating pipe 1, it is returned to the septic tank 2. The inlet part 1a of the heat absorbing / dissipating pipe 1 and the inside of the septic tank 2 are connected by a feed pipe 5, while the outlet part 1b of the heat absorbing / dissipating pipe 1 and the inside of the septic tank 2 are connected by a return pipe 6. Yes. The circulation pump 4 is disposed in the pipe line of the feed pipe 5 (in this embodiment, the end of the feed pipe 5). In addition, as a material of the said feed pipe 5 and the return pipe 6, the thing similar to the heat absorption / radiation pipe 1 mentioned above can be used. Moreover, in this Embodiment, although the submersible pump is used as the circulation pump 4, a normal ground installation type pump can also be arrange | positioned in the appropriate location outside the septic tank in the upper space in a septic tank. In this case, the circulation pump 4 is disposed in the middle of the pipe line of the feed pipe 5.

  In the present embodiment, a heat insulating material layer 7 covering the surface of the heat medium M stored in the septic tank 2 is provided in the septic tank 2. This heat insulating material layer 7 suppresses the heat of the heat medium M from escaping from the space above the septic tank 2 to the ground surface during snow melting, and the heat from the ground surface at the space above the septic tank 2 during cooling described later. It plays the role which suppresses that it is transmitted to the heating medium M via. Such a heat insulating material layer 7 can be obtained, for example, by laminating a foamed synthetic resin such as foamed polystyrene, foamed polyethylene, and foamed polyurethane into an appropriate shape such as a spherical shape, for example, to a thickness of about 5 cm. In FIG. 2, reference numeral 8 denotes a manhole cover of the septic tank 2, which is used for checking and cleaning the inside of the septic tank 2.

  In the present invention, the underground heat near the surface of the earth is used for melting snow together with solar energy. In the winter season when snow melting is required, the underground temperature near the septic tank is different depending on the region, but it is about 6-8 ° C even in February when it is the lowest. It is relatively higher than the temperature of the 10 mm deep part). For this reason, the heat medium M cooled in the process of passing through the heat absorbing / dissipating pipe 1 flows into the septic tank 2 and reduces the temperature of the heat medium M stored in the septic tank 2, but the temperature is relatively high. Heat transfer from the surrounding ground to the septic tank 2 occurs, and the heat medium M is warmed. Thereafter, the heated heat medium M is sent to the heat absorbing / dissipating pipe 1 by the circulation pump 4, and its heat energy is released from the heat absorbing / dissipating pipe 1, thereby suppressing a decrease in the surface temperature of the snow melting area E. Then, the heat medium M cooled in this process returns to the septic tank 2 and receives heat energy from the surrounding ground (snow melting operation).

  On the other hand, in the summer season, the underground temperature in the vicinity of the septic tank is relatively lower than the temperature below the surface of the snow melting area E. For this reason, the heating medium M heated in the process of passing through the heat absorbing / dissipating pipe 1 flows into the septic tank 2 and raises the temperature of the stored heating medium M. Thus, heat transfer from the septic tank 2 occurs, and the temperature of the heat medium M gradually decreases. Thereafter, the cooled heat medium M is sent to the heat absorbing and radiating pipe 1 by the circulation pump 4, absorbs heat energy from the heat absorbing and radiating pipe 1, and suppresses an increase in the surface temperature of the snow melting area E. Then, the heating medium M heated in this process returns to the septic tank 2 again and releases thermal energy to the surrounding ground (cooling operation). It should be noted that the surface temperature of the snow melting area E may become higher than the underground temperature due to the irradiation of the sun even in a period other than summer, for example, in winter, and in this case, cooling that suppresses the increase in the surface temperature of the snow melting area E. Driving is performed. Then, the heat stored in the heat medium M in the septic tank 2 by this cooling operation is used for melting snow, and the snow can be melted more efficiently by the increased temperature.

  FIG. 3 shows changes in the water temperature at the inlet and outlet of the heat absorbing and radiating pipe in a snow melting experiment using the system of the present invention. In FIG. 3, the solid line and the broken line indicate the water temperatures T1 and T2 of the inlet and outlet portions of the heat-absorbing and radiating pipe, respectively, and the alternate long and short dash line indicates the temperature T3 below the surface of the snow melting area (a portion having a depth of 10 mm from the surface). Is shown. In this experiment, the snow melting operation is performed when the temperature T3 of the snow melting area is 5 ° C. or less, and this corresponds to the period from the time of data collection to about 10 am. When there was a strong snowfall around 19:00, a slight amount of remaining snow was seen on the surface of the snowmelt area E, but the snowfall intensity was weakened after that. Then, the road surface dried. Meanwhile, the water temperature T1 at the inlet of the heat absorbing / dissipating pipe was about 7 ° C. and the water temperature T2 at the outlet was about 5 ° C., and a heat loss of about 2 ° C. was confirmed in the heat absorbing / dissipating pipe. The temperature T3 below the surface of the snow melting area E is always above the freezing point (0 ° C.) during the observation, and it is considered that a stable supply of geothermal energy ensures a sufficient snow melting function.

The above-described snow melting operation and cooling operation can be controlled by providing various sensors in the system S and using control means such as a microprocessor based on signals from the sensors. For example, a temperature sensor is installed below the surface of the snow melting area E (for example, a depth of 10 mm from the surface), and the temperature detected by the temperature sensor is lower than the ground temperature and higher than the freezing point. When the temperature is equal to or lower than the temperature, the heat medium M is sent to the heat absorbing and radiating pipe 1 to perform a snow melting operation for raising the temperature of the snow melting area E, and the temperature is lower than the ground temperature and higher than the first temperature. When the temperature reaches the second temperature, the snow melting operation can be stopped. That is, when the underground temperature is about 8 ° C., for example, the snow melting operation is started when the temperature becomes 5 ° C. (first temperature) or lower, and the snow melting operation is stopped when the temperature becomes 7 ° C. (second temperature) or higher. be able to. On the other hand, when the temperature is equal to or higher than a third temperature higher than the underground temperature, a cooling operation is performed to lower the temperature of the snow melting area E by sending the heat medium M to the heat absorbing and radiating pipe 1, and the temperature is The cooling operation can be stopped when the fourth temperature is higher than the ground temperature and lower than the third temperature. That is, it is possible to perform control such that the cooling operation is started when the temperature becomes 15 ° C. (third temperature) or higher, and the cooling operation is stopped when the temperature becomes 13 ° C. (fourth temperature) or lower. In this way, by setting the operation start and stop temperatures for each, and performing the snow melting operation and the cooling operation, the temperature increase in the snow melting area in the summer season or the like is suppressed, and the snow melting area and its surrounding environment are made comfortable. In addition, it is possible to increase the efficiency of snow melting by using the heat stored during the day for snow melting operation even in winter.
It is also possible to install a snowfall (snow accumulation) sensor in the vicinity of the snowmelt area E and perform a snowmelt operation based on a signal from this sensor. The control including the start and stop temperatures and the operation timing described above is merely an example, and can be variously changed depending on conditions such as the installation location of the system S and the capacity of the septic tank 2.

1 is an overall explanatory diagram of an embodiment of a system of the present invention. FIG. 2 is a cross-sectional explanatory view in the vicinity of a snow melting area in the system shown in FIG. 1. It is a graph which shows the water temperature change of the entrance part and exit part of an absorption-and-radiation pipe in the snow-melting experiment using the system of this invention.

Explanation of symbols

1 heat-absorbing and radiating pipe 2 septic tank 3 pump section 4 circulation pump 5 feed pipe 6 return pipe 7 heat insulating material layer S system M heat medium

Claims (4)

A heat absorbing / dissipating pipe laid in the snow melting area and through which a heat medium flows, an existing septic tank buried in the ground for wastewater treatment, a septic tank capable of storing the heat medium, and a septic tank in the septic tank A heat pump that sends the heat medium to the inlet portion of the heat absorbing / dissipating pipe and returning the heat medium from the outlet portion of the heat absorbing / radiating pipe into the septic tank, and a heat insulating material that covers the surface of the heat medium stored in the septic tank No watering snow melting system comprising: the layer, the. The pump part is disposed in a feed pipe connecting the inlet part of the heat absorbing and radiating pipe and the inside of the septic tank, a return pipe connecting the outlet part of the heat absorbing and radiating pipe and the inside of the septic tank, and a pipe line of the feed pipe The non-sprinkling snow melting system according to claim 1, comprising a circulating pump. The temperature sensor provided in the said snow melting area, and the control means which controls supply of the heat medium to the said heat absorption / radiation pipe based on the signal from this temperature sensor, The further any one of Claims 1-2 Non-sprinkling snow melting system according to crab. A heat absorbing / dissipating pipe laid in the snow melting area and through which a heat medium flows, an existing septic tank buried in the ground for wastewater treatment, a septic tank capable of storing the heat medium, and a septic tank in the septic tank While sending a heat medium to the inlet part of the said heat absorption / radiation pipe, the pump part which returns the heat medium from the exit part of the said heat absorption / radiation pipe in the said septic tank, the temperature sensor provided in the said snow melting area, and this temperature sensor Operation of a non-sprinkling snow melting system comprising: control means for controlling supply of a heat medium to the heat absorbing / dissipating pipe based on a signal from a heat insulating material layer covering a surface of the heat medium stored in the septic tank A method,
When the temperature detected by the temperature sensor is equal to or lower than a first temperature that is lower than the ground temperature and higher than the freezing point, the snow-melting operation is performed to raise the temperature of the snow-melting area by sending the heat medium to the heat absorbing and radiating pipe. When the temperature reaches a second temperature lower than the ground temperature and higher than the first temperature, the snow melting operation is stopped, and when the temperature is equal to or higher than the third temperature higher than the ground temperature. The cooling medium is sent to the heat-absorbing and radiating pipe to lower the temperature of the snow melting area, and the cooling operation is stopped when the temperature reaches a fourth temperature that is higher than the ground temperature and lower than the third temperature. A method of operating a non-sprinkling snow melting system.

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