JP3134147B2 - Control method of geothermal snow melting system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control of a heat medium road snow melting system that collects and uses abundant low-level geothermal power which does not change throughout the seasons for air conditioning, hot water supply, heated water pool, plant cultivation, animal breeding, snow melting, etc. It is about the method.

[0002]

Conventionally, the standing dispersed throughout, although it is quantitatively abundant, the use of low levels of geothermal, the low level of the hot water was pumped from the underground in particular, air-conditioning and hot water supply, warm water pool plant cultivation - Efficient use for animal breeding, snow melting, etc. has not progressed much. The main reason for this is that a large amount of groundwater is pumped out during use, which causes land subsidence and
There is a risk of causing environmental destruction and pollution such as lowering of groundwater and difficulty in wastewater treatment and management.

In addition, a heat exchanger for extracting geothermal heat is buried underground, a heat medium is sent to the heat exchanger, and indirect heat exchange is performed between the heat and the heat medium via a heat transfer surface to collect and use the geothermal heat. Although a method has been proposed, there is no good means for efficiently extracting geothermal heat that is suitable for geothermal characteristics.

[0004]

The problem to be solved is that there has been no proposal for a control method of a heat medium type road surface snow melting system which is adapted to the characteristics of conventional geothermal heat and efficiently collects and uses geothermal heat. Accordingly, the present invention provides a method of controlling a snow melting system for a road surface that efficiently collects and uses geothermal heat, which solves the above problem.

[0005]

Means for Solving the Problems According to the invention of claim 1, the heat medium M is sent downward by the inner tube of the concentric double tube for heat exchange 1 in which the inner tube is concentrically inserted into the outer tube, and then inverted. hand,
The heat radiation part 9 receives the geothermal heat received by guiding the inside of the outer pipe upward.
And a heat medium circulating path 3 for circulating a heat medium M between a plurality of concentric double tubes 1 and a heat radiating portion 9 composed of a plurality of sets of heat radiating tubes 9b. circulating the heat medium M by the heat medium circulation pump 2, 2 to be used as a spare, the road surface temperature sensor 6f, winter track temperature driving heat medium circulation pump 2 with the following winter road setting a temperature L ₁ , stopping the heat medium circulation pump 2 winter road set on temperature H ₁ or more, summer driving heat medium circulation pump 2 at the road surface temperature in summer road set on temperature H ₂ or more, summer road setting a temperature L ₂ may stop heat medium circulation pump 2 below, to absorb the change in volume of the heat medium M due to temperature changes due to expansion tank 4 communicating with the heating medium circulation path 3, the pressure switch 5 of the heating medium M When the pressure below the set pressure lower limit due to leakage is detected, the heat medium This is a control method for a heat medium type geothermal snow melting system which stops the operation of the ring pump 2 and issues an alarm.

According to a second aspect of the present invention, the allowable road surface setting temperature difference of the first aspect is 0 to 10 ° C in winter and 0 to -10 ° C in summer.
It is something that is.

[0007]

Embodiments of the present invention are described below.
Referring to FIGS. 1 to 3, reference numeral 1 denotes a concentric double tube for heat exchange which is buried vertically in the ground to collect geothermal heat, and an inner tube is inserted concentrically into an outer tube receiving geothermal heat. In the case where a plurality of cables are installed in the same place, they must be separated by at least 5 m in order to avoid mutual thermal interference. The outer tube (diameter 9)
0 mm) and the inner tube (56 mm) are both made of hard polyethylene.

The concentric double tube 1 for heat exchange will be described in further detail.
Is sent downward, turned upside down, guided upward between the outer pipe and the inner pipe, and sent to the heat radiating portion 9 such as snow melting on the road. The heat radiating portion 9 is a portion that is laid on the road surface, passes through the heat medium M sent from the plurality of concentric double tubes 1 and melts snow, and includes a plurality of heat radiating tubes 9b on three headers 9a. Connected.

Reference numeral 2 denotes a heat medium circulating pump, and one pump is provided for 14 to 6 concentric double tubes except for the spare (one of the two is spare) and 3 is a heat medium M , A feed pipe main pipe, 3b a return pipe main pipe, 3d a flow meter, and 3e an automatic air vent valve.

Reference numeral 4 denotes an expansion tank which communicates with the heat medium circulation path 3 and absorbs a change in the volume of the heat medium M, 4a is a pressure gauge, 4b is a relief valve, 4c is an automatic air release valve, and 5 is a pressure switch. The operation of the heat medium circulation pump 2 is stopped when a pressure lower than the set pressure lower limit value due to the leakage of the heat medium M or the like is detected.

6a is a four-point underground temperature sensor for measuring the temperature outside the concentric double tube 1, and 6b is a two-point temperature sensor in the heat exchanger for measuring the temperature of the heat medium M inside the concentric double tube 1. ,
6c is an inlet temperature sensor for measuring the temperature of the heat medium M at the inlet of the concentric double pipe 1, 6d is an outlet temperature sensor for measuring the temperature of the heat medium M at the outlet of the concentric double pipe 1, and 6e and 6f are road surface temperature sensors. One is used as a control for starting and stopping the heat medium circulation pump 2. 6 g is an outside air temperature sensor.

7 is a control panel, 7a is a recorder for recording the outside air temperature in addition to the above temperature, and a start / stop of a heat medium circulation pump.
A remote monitoring data converter for transferring data to a remote location using a telephone line. The main data is a state of a main power supply, an abnormality of two heat medium circulation pumps 2 and 2, a pressure drop,
The pump operation for heat medium circulation, the setting mode for summer / winter, and the like.

Furthermore, the allowable road surface setting temperature difference Δt is set to 0 in winter.
-10 ° C, 0-10 ° C in the summer, and the road surface temperature is set to the road surface setting temperature L in winter according to the value of the road surface temperature sensor 6f.
_When it becomes ₁ or less, the heat medium circulation pump is started, and the radiating pipe 9b is started.
And heats the road surface and melts it if there is snow, but the road surface temperature is set to the road surface setting temperature H ₁ (> = L + 0).
If it is not less than -10 ° C), the heat medium circulation pump is stopped. Note RL, GL, OL respectively red light, green light, and orange color lights.

Also, in summer, the road surface temperature is set at a road surface setting temperature H.
_When it becomes ₂ or more, the heat medium circulation pump is started, and the heat radiation pipe 9b is started.
The heat medium M is sent to the cooling medium to cool the road surface and store the heat received by the heat medium M in the ground.
_{When the} temperature falls below ₂ (<= H + 0 to -10 ° C.), the heat medium circulation pump is stopped.

FIGS. 2 and 3 show control flowcharts. First performed the season mode setting of summer and winter, and enter the control state, as described above, the value of the road surface temperature sensor 6f, winter is when the road surface temperature is equal to or less than the road surface set a temperature L ₁ a heat medium circulation pump start-up Then, the heat medium M is sent to the heat radiating pipe 9b to heat the road surface and melt if snow is present, but if the road surface temperature is equal to or higher than the road surface setting temperature H ₁ (> = L + 0 to 10 ° C.), the heat medium is circulated. Set to stop the pump.

Heat medium circulation When one of the heat medium circulation pumps 2 is started, the heat medium M is distributed to each concentric double pipe 1 through the feed pipe main pipe 3a of the heat medium circulation path 3, and each concentric double pipe 1 is conveyed. It is sent downward by the inner pipe of the heavy pipe 1, is inverted, and is heated by receiving geothermal heat while being guided upward in the outer pipe. Each concentric double tube 1
Is passed through the heat medium circulation path 3 to the heat radiating section 9 and is distributed to the plurality of headers 9a. Further, the heat medium M is distributed to the plurality of heat radiating pipes 9b at each header 9a, thereby heating the road surface and melting snow. After being used for (cooling and heat storage of the road surface in summer), it is returned to each concentric double pipe 1 via the return main pipe 3b by the heat medium circulation pump 2.

In the meantime, 20 to 25 per concentric double tube
The heating medium M is controlled so as to flow in liter / min. When the volume of the heating medium M changes due to a temperature change, the change in volume is absorbed by the expansion tank 4. Further, when a pressure lower than the set pressure lower limit value due to leakage of the heat medium M or the like is detected, the pressure switch 5 is operated, and the operation of the heat medium circulation pump 2 is stopped.

[0018]

Since the present invention is configured as described above, it is possible to automate the heat medium type snow melting system using geothermal heat, and to use the geothermal heat to heat and melt the road surface in winter and to cool and store the road surface in summer respectively. If it is not necessary, the operation of the heat medium circulation pump is stopped to save power,
Operating costs can be reduced.

[Brief description of the drawings]

FIG. 1 is a device configuration diagram showing an embodiment of the present invention.

FIG. 2 is a part of a control flow chart of the present invention.

FIG. 3 is the remainder of the control flow diagram of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Concentric double pipe 2 Heat medium circulation pump 3 Heat medium circulation path 3a Feed pipe main pipe 3b Return pipe main pipe 3d Flow meter 3e Automatic air release valve 4 Expansion tank 4a Pressure gauge 4b Relief valve 4c Automatic air release valve 5 Pressure Switch 6a Underground temperature sensor 6b Temperature sensor in heat exchanger 6c Inlet temperature sensor 6d Outlet temperature sensor 6e Road surface temperature sensor 6f Road surface temperature sensor 6g Outside air temperature sensor 7 Control panel 7a Recorder 7b Data converter for remote monitoring 9 Radiator 9a header 9b radiator tube GL green light H ₁ winter on the road set temperature H ₂ summer on the road surface temperature setting L ₁ in winter under road set temperature L ₂ summer under road set temperature M heating medium OL orange color lights RL red light

Claims (2)

(57) [Claims] 1. A heat medium (M) is fed downward by an inner tube of a concentric double tube for heat exchange (1) in which an inner tube is inserted concentrically in an outer tube, and then inverted, so that the inside of the outer tube is moved upward. The ground heat received by the guiding is sent to the heat radiating section (9) and used for melting snow, and a heat medium is passed between the heat radiating section composed of a plurality of concentric double pipes and a plurality of sets of the heat radiating pipes (9b). The heat medium circulation path (3) to be circulated
The heat medium (M) is circulated by the heat medium circulation pump (2), one of which is used as a spare. The road surface temperature sensor (6f) allows the road surface temperature in winter to be lower than the winter road surface set temperature (L ₁ ) or lower. Operate the medium circulation pump and stop the heat medium circulation pump at or above the winter road setting temperature (H ₁ ). In summer, the road medium temperature is at or above the summer road surface setting temperature (H ₂ ). , And set the temperature under the summer road surface setting (L ₂ )
In the following, stop the pump for circulating the heat medium, absorb the volume change of the heat medium accompanying the temperature change by the expansion tank (4) communicating with the heat medium circulation path, leak the heat medium by the pressure switch (5), etc. A method for controlling a heat medium type geothermal snow melting system, comprising: stopping the operation of a heat medium circulation pump and issuing an alarm when a pressure lower than a set pressure lower limit value is detected. 2. The allowable road surface setting temperature difference is 0 to 10 in winter.
2. The method according to claim 1, wherein the temperature is 0 to −10 ° C. in summer.