JP2020097880A - Road surface heating system - Google Patents

Abstract

To provide a road surface heating system having a high power saving effect while obtaining a high heating effect according to environmental characteristics such as snowfall and temperature conditions in a heating target area.SOLUTION: A road surface heating system 10 includes: a first heat exchange circuit that circulates a heat exchange medium through a first heat exchange tube 12 buried in the ground and a second heat exchange tube 14 buried in a heat exchange target area 13; and a second heat exchange circuit that circulates the heat exchange medium through the first heat exchange tube 12 and a heat source side heat exchanger 22 of a heat pump H, and circulates the heat exchange medium through the second heat exchange tube 14 and a load side heat exchanger 26 of the heat pump H. Switching between a first operation in which the heat pump H is stopped and circulation is performed by the first heat exchange circuit and a second operation in which the heat pump H is activated and circulation is performed by the second heat exchange circuit is performed based on detection results of an environment detection device 16 that detects the surrounding environment of the heat exchange target area 13.SELECTED DRAWING: Figure 1

Description

The present invention relates to a road surface heating system, and more particularly to a road surface heating system capable of heating a road surface by utilizing underground heat.

Conventionally, in order to remove snow on roads and to prevent freezing of the road surface, a heat dissipation pipe or heat dissipation line is buried under the road, and heat is dissipated from the heat exchange medium flowing through the heat dissipation pipe and the heat dissipation line is energized. There is known a snow melting device that heats a road surface to remove snow and freeze.

For example, in Patent Document 1, a heat collecting pipe is buried in the vicinity of the outer wall of a sewer pipe buried in the ground, and a heat radiating pipe is buried in an area of the ground where snow is melted, and the heat collecting pipe and the heat radiating pipe circulate. A snow melting device for circulating a heat exchange medium in a road is described. In this device, sewage heat is collected when the heat exchange medium passes through the heat collecting pipe, and the heat is released to the outside in the heat radiating pipe to perform snow melting in the region where the heat radiating pipe is embedded.

Moreover, in patent document 1, the 1st circulation path which circulates the heat exchange medium for heat sources to the heat-collection pipe|tube arrange|positioned near the outer wall of a sewer pipe, and the heat-source side heat exchanger of a heat pump, and the load side heat exchange of a heat pump. A snow melting apparatus is described, which includes a container and a heat radiating pipe embedded in a snow melting region, and a second circulation path for circulating a heat exchange medium for heat radiation.

In this snow melting device, the sewage heat collected when the heat source side heat exchange medium passes through the heat collection tube is absorbed by the heat source side heat exchanger of the heat pump, and is used to heat the heat radiating heat exchange medium in the heat pump load side heat exchanger. doing. When the heated heat exchange medium for heat dissipation passes through the heat dissipation pipe, heat is dissipated to melt the ground.

JP, 2002-013105, A

In the above-described snow melting device, in a device that does not use a heat pump, sewage heat can be directly used as a heat source for snow melting, and since power for driving the heat pump is not required, running costs can be kept low. it can.

However, in an area with a large amount of snowfall, such as a heavy snowfall area, there is a problem that the amount of heat for sewage heat will be insufficient for melting snow, and snow will remain.

On the other hand, in a device using a heat pump, the temperature of the heat exchange medium for heat dissipation can be made higher than the temperature of the sewage by the heat pump, so even if the amount of snowfall is large, snow melting will not occur. It can be carried out. Further, it is possible to prolong the life of the device as compared with one in which a heating wire is buried and the road surface is heated by energization.

However, if the heat pump is always operated when performing snow melting or the like , the power consumption becomes large, and therefore there has been a demand for the development of a device that can save power while obtaining an appropriate snow melting effect.

The present invention has been made in view of the above problems, and an object thereof is to provide a road surface heating system having a high power saving effect while obtaining a high heating effect according to environmental characteristics such as snowfall and temperature conditions in a heating target area. The purpose is to do.

The road surface heating system according to the present invention for achieving the above object,
A first heat exchange tube that is buried in the ground, and a second heat exchange tube that is buried in a heat exchange target area closer to the road surface than the first heat exchange tube. Heat exchange circuit of
A first circulation path for circulating the heat exchange medium to the first heat exchange tube and the heat source side heat exchanger of the heat pump; and a second circulation path to circulate the second heat exchange tube and the load side heat exchanger of the heat pump. A second heat exchange circuit forming two circulation paths;
An environment detection device for detecting the surrounding environment of the heat exchange target area,
A first operation in which the heat pump is stopped and circulation is performed by the first heat exchange circuit, and a heat pump is operated and circulation is performed by the second heat exchange circuit based on a detection result of the environment detection device. A control unit that can be replaced with the second operation,
It is characterized by having.

According to this configuration, when the heat exchange target area (that is, the heating target area where the road surface is heated to melt snow) is heated, based on the detection result of the environment detection device (for example, the road surface temperature or the amount of snowfall). , A first operation of stopping the heat pump to circulate the heat exchange medium in the first heat exchange circuit and operating the heat pump to supply the heat exchange medium to the second heat exchange circuit according to the environmental conditions at that time. It is possible to switch to the second operation of circulating.

Thereby, when the lower heating temperature is sufficient depending on the situation of the surrounding environment, it is possible to switch to the first operation and eliminate the amount of electric power for operating the heat pump, thereby achieving energy saving. When the required heating temperature is high, the heat pump is operated by the second operation, so that the heat energy of the first heat exchange tube is used by the heat pump while the heat flowing through the second heat exchange tube is used. Since the temperature of the exchange medium can be made higher than the temperature of the heat exchange medium flowing through the first heat exchange pipe, the heating target region can be heated at a high temperature. This makes it possible to appropriately heat the road surface with high thermal energy and perform snow melting when the load for snow melting increases, such as when the amount of snowfall is large, while suppressing the power consumption of the heat pump.

Further, the present invention is the above road surface heating system,
The first heat exchange pipe is arranged on the outer peripheral surface or inside of a buried pipe which is buried in the ground and through which a fluid flows.

According to this configuration, the road surface can be heated by using the thermal energy collected from the fluid flowing through the conduit of the buried pipe.

Further, the present invention is the above road surface heating system,
The environment detection device detects at least one of an outside air temperature around the heat exchange target area, a road surface temperature of the heat exchange target area, and presence or absence of snowfall in the heat exchange target area. ..

According to this configuration, the environment detection device detects elements that cause snowfall and road surface freezing in the heating target area, and switches the circulation path of the heat exchange medium so that snowfall and the like are prevented based on the detection result. , It is possible to carry out appropriate snow melting and freezing prevention according to the surrounding environment.

Further, the present invention is the above road surface heating system,
The control unit may perform a preheating operation that repeats circulation and stop of the heat exchange medium in the first heat exchange circuit at a predetermined cycle time when the operation is started.

According to this configuration, it is possible to enhance the power saving effect of the system by performing the preheating operation in which the first operation and the circulation stop are repeated at the start of operation when it is estimated that the heating temperature in the heating target region may be relatively low. it can.

Further, the present invention is the above road surface heating system,
The environment detection device detects the outside air temperature around the heat exchange target area and the road surface temperature of the heat exchange target area,
The control unit is
When the outside air temperature is equal to or lower than a predetermined first outside air temperature, or the road surface temperature is equal to or lower than a predetermined first road surface temperature, the preheating operation is started,
After starting the preheating operation,
While the operation is stopped when the outside air temperature exceeds a predetermined second outside air temperature higher than the first outside air temperature, or the road surface temperature exceeds a predetermined second road surface temperature higher than the first road surface temperature,
The first operation is continued when the outside air temperature is equal to or lower than a predetermined third outside air temperature lower than the first temperature, or when the road surface temperature is equal to or lower than a predetermined third road surface temperature lower than the first road surface temperature. It is characterized in that

According to this configuration, after the preheating operation, when the outside air temperature or the road surface temperature exceeds a predetermined temperature higher than that at the start of the preheating operation, the operation can be stopped to save energy. Further, when the outside air temperature or the road surface temperature becomes equal to or lower than a predetermined temperature lower than that at the start of the preheating operation, the first operation can be continued to heat the heating target area with higher heat energy.

Further, the present invention is the above road surface heating system,
The environment detection device detects the presence or absence of snowfall, the amount of water on the road surface in the heat exchange target area, and the road surface temperature of the heat exchange target area,
The control unit is
When there is snowfall, the detected water content exceeds a predetermined water content, and the detected road surface temperature is equal to or lower than a predetermined first switching reference road surface temperature, the first operation is switched to the second operation,
During the second operation, the detected water content exceeds the predetermined water content, and the detected road surface temperature is equal to or higher than a predetermined second switching reference road surface temperature higher than the first switching reference road surface. , Switch to the first operation,
During the second operation, the operation is stopped when the detected water content is equal to or less than the predetermined water content.

According to this configuration, when there is snowfall, the amount of water on the road surface in the heating target region exceeds the predetermined amount of water, and the road surface temperature is equal to or lower than the predetermined first switching reference road surface temperature, that is, the snow on the road surface is If predicted, it is possible to switch to the second operation and heat the target area at a high temperature. In addition, during the second operation, energy can be saved by switching the operation to the first operation or stopping the operation depending on the amount of water on the road surface and the road surface temperature.

Further, the present invention is the above road surface heating system,
At least the first circulation path and the second circulation path are provided with an expansion tank that allows a volume change of the heat exchange medium.

According to this configuration, the expansion tank is provided in the circulation path in which the temperature of the heat exchange medium fluctuates greatly by switching the heat exchange circuit, so that the expansion tank allows the volume change of the heat exchange medium due to the temperature change, and the circulation path. The volume capacity of the heat exchange medium flowing through can be maintained uniform.

According to the present invention, it is possible to switch between the first operation that does not use the heat pump and the second operation that uses the heat pump, depending on the surrounding environment of the heating target area, such as the snowfall condition. It is possible to save energy by saving electricity while obtaining high snow melting effect and freezing prevention effect.

The block diagram of the road surface heating system which is one embodiment of the present invention. The figure which shows the flow of the heat exchange medium in a 1st heating circuit. The figure which shows the flow of the heat exchange medium in a 2nd heating circuit. Sectional drawing explaining the heat exchange mechanism by a heat collection tube. The flowchart figure which shows operation|movement of a control part. The flowchart figure which shows operation|movement of a control part.

FIG. 1 is a configuration diagram of a road surface heating system 10 according to an embodiment of the present invention. The road surface heating system 10 includes a heat collection pipe (first heat exchange pipe) 12 arranged inside or outside a sewer pipe (embedded pipe) 11 buried in the ground, and heating closer to the road surface than the heat collection pipe. A heat radiation pipe (second heat exchange pipe) 14 embedded in a target region (heat exchange target region) 13, a heat pump H, an environment detection device 16, and a controller (not shown) are provided. The sewer pipe 11 is arranged between the two manholes and communicates the two manholes. In FIG. 1, only one manhole 60 is shown. The heat pump H includes a compressor 20, a heat source side heat exchanger 22, an expansion valve 24, and a load side heat exchanger 26.

Further, the road surface heating system 10 includes a heat source side circulation path (first circulation path) 30 for circulating a heat exchange medium between the heat collection tube 12 and the heat source side heat exchanger 22, a heat radiation tube 14 and a load side heat exchanger 26. A direct connection for circulating the heat exchange medium by directly connecting the heat collecting pipe 12 and the heat radiating pipe 14 without the heat pump H and the load side circulation passage (second circulation passage) 40 for circulating the heat exchange medium to and from And a circulation path 50.

The heat source side circulation path 30 is connected to the heat collecting pipe 12, the first pipe 30a extending from the downstream end of the heat collecting pipe 12 to the heat source side heat exchanger 22, and the heat source side heat exchanger 22 by being connected to the downstream end of the first pipe 30a. It has the heat source side piping 30b which passes inside, and the 2nd piping 30c which connects the downstream end of the heat source side piping 30b and the upstream end of the heat collection tube 12.

The load side circulation path 40 is connected to the heat radiating pipe 14, the third pipe 40a extending from the downstream end of the heat radiating pipe 14 to the load side heat exchanger 26, and the downstream end of the third pipe 30a to connect the load side heat exchanger 26. It has the load side piping 40b which passes inside, and the 4th piping 40c which connects the downstream end of the load side piping 40b and the upstream end of the radiation pipe 14.

The direct connection circulation path 50, together with the heat collection pipe 12 and the heat dissipation pipe 14, are connected to the first direct connection pipe 50a that connects the first pipe 30a and the fourth pipe 40c, and the second connection pipe that connects the second pipe 30b and the third pipe 40a. The direct connection pipe 50b is included. Switching valves 52, 53, 54, 55 are arranged at the upstream and downstream ends of the first and second direct coupling pipes 50a, 50b, respectively, so that the flow paths of the heat exchange medium can be switched.

In the present embodiment, the switching valves 52, 53, 54, 55 are three-way valves, and as shown in FIG. 2, the heat source side circulation passage 30 and the load side circulation passage 40 are shut off and the heat exchange medium is connected to the direct connection circulation passage 50. And a second heating circuit that circulates the heat exchange medium in each of the heat source side circulation path 30 and the load side circulation path 40 by shutting off the direct connection circulation path 50 as shown in FIG. The flow path can be switched to and.

The same fluid is used as the heat exchange medium flowing through the circulation paths 30, 40, 50. The type of the heat exchange medium is not particularly limited, but, for example, water or a mixture of water and alcohol or ethylene glycol (antifreeze liquid) can be used.

A pump that circulates the heat exchange medium is arranged in each circulation passage 30, 40, 50, and in this embodiment, the pump in the direct connection circulation passage 50 is arranged in the heat source side circulation passage 30 and/or the load side circulation passage 40. It also serves as the pumps 34 and 44 that are operated. Further, temperature sensors 46 and 48 are arranged on the upstream side and the downstream side of the heat radiation pipe 14, respectively. In the illustrated example, the temperature sensors 46 and 48 are provided in the third pipe 40a and the fourth pipe 40c, and the temperature sensor 36 is further provided in the first pipe 30a. Each of the temperature sensors 36, 46, 48 directly or indirectly detects the temperature of the heat exchange medium flowing in the pipe.

Further, the heat source side circulation path 30 and the load side circulation path 40 are provided with expansion tanks 32 and 42, respectively. The expansion tanks 32 and 42 absorb the volume change of the heat exchange medium flowing through the circulation paths 30 and 40. In the present embodiment, the expansion tanks 32 and 42 are arranged so as to be shared in the direct connection circulation path 50.

Although not shown, a flow meter for measuring the flow rate of the heat exchange medium flowing in the circulation passages, or a pressure gauge for measuring the pressure in the circulation passages may be appropriately provided in each circulation passage 30, 40, 50. It is possible.

The heat pump H includes a compressor 20 that compresses the refrigerant, a heat source side heat exchanger 22, an expansion valve 24 that expands the refrigerant, a load side heat exchanger 26, and a refrigerant pipe 28 through which the refrigerant that circulates flows. Equipped with. The refrigerant circulates through the refrigerant pipe 28 forming a closed loop in the heat pump H, and undergoes a heat cycle of evaporation, compression, condensation, and expansion. In the heat source side heat exchanger 22, heat is exchanged between the heat exchange medium passing through the heat source side pipe 30b and the refrigerant, and in the load side heat exchanger 26, the heat exchange medium passing through the load side pipe 40b and the refrigerant. A heat exchange is performed between and.

The heat collecting pipe 12 and the heat radiating pipe 14 are each made of a material having high heat conductivity and durability, and constitute a heat exchange mechanism for transferring heat inside and outside the pipe.

Next, the heat exchange mechanism 70 using the heat collecting tube 12 will be described with reference to FIG. Note that FIG. 4 is a cross-sectional view of a portion indicated by line IV-IV in FIG.

The heat exchange mechanism 70 includes a heat exchange mat 72 formed by the plurality of heat collection tubes 12, and a fixing member 74 that fixes the heat exchange mat 72 to the sewer pipe 11. The heat exchange medium that has passed through the second pipe 30c is split into the plurality of heat collection pipes 12 arranged in the sewer pipe 11, and then merges in the first pipe 30a.

The heat exchange mat 72 is formed in a mat shape by connecting a plurality of heat collecting tubes 12 in parallel and mutually connected. The heat collecting tubes 12 are connected and fixed to each other by a connecting member which is integral with or separate from the heat collecting tubes 12. In the present embodiment, the heat collecting tube 12 is made of a resin material having high corrosion resistance, for example, PP resin, PBT resin, PET resin, PE resin, rubber material, etc., and the heat exchange mat 72 can be used as a whole. It is formed as a long plate having flexibility. In the example shown in FIG. 1, each heat collection tube 12 extends from one manhole 60 toward the other manhole, is folded back at the tip of the heat exchange mat 72, and extends back to the manhole 60 side. In the illustrated example, the heat collecting tube 12 has a circular cross section, but the cross sectional shape is not limited to this, and may be an elliptical shape, a polygonal shape, or any other shape that allows the heat exchange medium to flow.

The fixing member 74 is a rehabilitation pipe made of a tubular body provided over the entire inner peripheral surface of the sewer pipe 11, and is formed of a lining material for rehabilitating the sewer pipe 11. The heat exchange mat 72 is pressed and fixed to the inner wall of the sewer pipe 11 by the fixing member 74.

Note that the fixing member is not limited to the rehabilitation pipe, and may be any member that can fix the heat exchange mat 72 in the sewer pipe 11. For example, the fixing member may be a ring-shaped or arc-shaped member that is arranged along the inner wall surface of the sewer pipe 11 and is arranged in plural at intervals in the axial direction of the sewer pipe 11. The replacement mat 72 may be partially pressed from the inside of the sewer pipe 11 to the inner wall of the sewer pipe 11 to be fixed.

The radiating pipe 14 is buried below the road surface that is the area 13 to be heated, where snow melting and freezing are prevented. In the example shown in FIG. 1, one heat radiation pipe 14 extends below the road surface in a meandering state. The radiating pipe 14 is buried in a position relatively close to the ground surface, and preferably has a rigidity higher than that of the heat collecting pipe 12 in the sewer pipe 11 so as to withstand vibrations of a vehicle or the like. For example, a stainless pipe or carbon steel. A metal pipe such as a steel pipe can be used.

In the area of the heating target area 13 and/or in the vicinity of the area, an environment detection device 16 that detects the surrounding environment of the heating target area 13 is installed. The environment detection device 62 is, for example, a camera capable of monitoring the snowfall situation or the snowfall situation of the heating target area 13, a temperature sensor detecting the outside air temperature of the heating target area 13, and an infrared ray detecting the surface temperature of an object such as a road surface. A thermo sensor, a moisture sensor that detects the amount of moisture on the road surface of the heating target region 13, or the like may be used alone or in combination.

Environment detection device 16 in the present embodiment, the presence or absence of snow in the heating target region 13, the outside air temperature T _A of the peripheral heat target region _13, the road surface temperature T _R of the heating target region _13, the moisture content of the road surface in the heating target region 13 (Presence or absence of water) W can be detected.

The environment detection device 16, the temperature sensors 36, 46 and 48, the heat pump H, the flow meter, the pressure gauge, and the pumps 34 and 44 are wired or wirelessly connected to the control unit of the road surface heating system 10.

The control unit includes a ROM that stores a program for performing each operation, a RAM that temporarily stores data based on signals output from each sensor, and a CPU that executes each program. The control unit controls the operation of the heat pump H and the switching of each heating circuit by the operation of the switching valves 52, 53, 54, 55 based on the detection signal from each connected device. Specifically, the control unit performs a low-temperature heating operation (first operation) in which the heat pump H is stopped and circulation is performed by the first heating circuit, and a heat pump H is operated to perform circulation by the second heating circuit. The operation of the road surface heating system 10 can be switched to the high temperature heating operation (second operation). The low-temperature heating operation is an energy-saving operation capable of achieving energy saving as compared with the high-temperature heating operation in which the heat pump H operates (that is, the normal operation). Further, in the low temperature heating operation, it is possible to switch between a preheating operation in which circulation and stop of the heat exchange medium are repeated in a predetermined time cycle, and a continuous low temperature heating operation in which circulation of the heat exchange medium is continuously performed.

The control unit includes reference outside air temperatures T _A1 (first outside air temperature), T _A2 (second outside air temperature), T _A3 (third outside air temperature) and T, which serve as references for switching the operating state of the road surface heating system 10. _A4 , reference road surface temperature _TR1 (first road surface temperature), _TR2 (second road surface temperature), _TR3 (third road surface temperature), _TR4 and _TR5 (second switching reference road surface temperature), and reference road surface A water content (that is, a threshold value that serves as a reference for the presence or absence of water) W ₁ is set in advance.

Here, the values (higher temperatures) of the reference outside air temperatures T _{A1 to} T _A4 are T _A3 <T _A1 <T _A2 , T _A1 <T _A4 , and 0° C. <T _A1 , and preferably 0° C. <T _A1. 0° C.<T _A3 . As an example, T _A1 =4° C., T _A2 =5° C., T _A3 =2° C., T _A4 =5° C. can be set.

The value of the reference road surface temperature _T R1 _{through T R5 is, T R3 <T R1 <T} R2, 0 ℃ <T R1 <T R4, and a _{0 ℃ <T R5 <T R4} , preferably _T R5 <T _R1 . As an example, T _R1 =4°C, T _R2 =7°C, T _R3 =2°C, T _R4 =7°C, T _R5 =2°C can be set.

In the road surface heating system 10 described above, when the low temperature heating operation is selected by the control unit and switched to the first heating circuit shown in FIG. 2, the heat exchange medium circulates in the direct connection circulation path 50 by the pressure of the pumps 34 and 35. Then, heat is exchanged with the sewage 78 when passing through the heat collecting pipe 12, sewage heat is collected, and heat is released when passing through the heat radiating pipe 14, whereby the heating target region 13 is heated.

When the control unit selects the high temperature heating operation and switches to the second heating circuit shown in FIG. 3, the heat exchange medium of the heat source side circulation passage 30 and the load side circulation passage 40 is changed by the pressure of the pumps 34 and 35. Circulate each. In the heat source side circulation path 30, the sewage heat obtained when the heat exchange medium passes through the heat collecting tube 12 is used as a heat source in the heat source side heat exchanger 22 of the heat pump H. In the load side circulation path 40, the heat exchange medium releases the heat acquired in the load side heat exchanger 26 of the heat pump H to the heat radiating pipe 14, so that the heating target region 13 can be heated at a temperature higher than the sewage. Becomes

Next, the control of the road surface heating system 10 by the control unit will be described. FIG. 5 is a flowchart showing the operation of the control unit.

When the control process starts, the control unit determines that the outside air temperature T _A detected by the environment detection device 16 is the predetermined reference outside air temperature T _A1 or less, or the detected road surface temperature T _R is the predetermined reference road surface temperature T _R1 or less. It is determined whether or not there is (step S110).

When the outside air temperature T _A is higher than the reference outside air temperature T _A1 and the road surface temperature T _R is higher than the reference road surface temperature T _R1 (step S110: No), the control unit stops the operation of the road surface heating system 10 (step S111). , The process ends.

On the other hand, when the outside air temperature T _A ≦T _A1 or the road surface temperature T _R ≦T _R1 (step S110: Yes), the preheating operation is started (step S112).

After starting the preheating operation, the control unit determines whether the detected outside air temperature T _A is equal to or lower than a predetermined reference outside air temperature T _A2 , or the detected road surface temperature T _R is equal to or lower than a predetermined reference road surface temperature T _R2. Yes (step S113). When the outside air temperature T _A is higher than the reference outside air temperature T _A2 and the road surface temperature T _R is higher than the reference road surface temperature T _R2 (step S113: No), the control unit stops the preheating operation of the road surface heating system 10 (step S111). ), the processing ends.

On the other hand, when the outside air temperature T _A ≦the reference outside air temperature T _A2 or the road surface temperature T _R ≦the reference road surface temperature T _R2 (step S113: Yes), the outside air temperature T _A is further equal to or lower than the predetermined reference outside air temperature T _A3. or, road surface temperature _{T R} is equal to or less than a predetermined reference road surface temperature _{T R3} (step S114).

When the outside air temperature T _A is higher than the reference outside air temperature T _A3 and the road surface temperature T _R is higher than the reference road surface temperature T _R3 (step S114: No), the preheating operation is continued (step S112).

On the other hand, when outside air temperature T _A ≦reference outside air temperature T _A3 or road surface temperature T _R ≦reference road surface temperature T _R3 (step S114: Yes), it is further determined whether or not there is snowfall in the heating target area 13 ( Step S115).

If there is no snowfall (step S115: No), the process returns to step S112 to continue the preliminary operation, and the subsequent processing is sequentially executed. If there is snowfall (step S115: Yes), the preheating operation is switched to the continuous low-temperature heating operation of continuously circulating the heat exchange medium (step S116). Then, the water content W of the road surface in the heating target area 13 is detected, and it is determined whether or not the detected water content W is larger than a predetermined reference water content W ₁ (step S117).

When the water content W is equal to or less than the reference water content W ₁ (step S117: No), the control unit stops the operation (step S111) and ends the process.

When the detected water content W exceeds the reference water content W ₁ (step S117: Yes), the outside air temperature T _A and the road surface temperature T _R are detected, and the detected outside air temperature T _A is the predetermined reference outside air temperature T _A4. Below, or it is determined whether or not the road surface temperature T _R is equal to or lower than a predetermined reference road surface temperature T _R4 (step S118).

When the outside air temperature T _A is higher than the reference outside air temperature T _A4 and the road surface temperature T _R is higher than the reference road surface temperature T _R4 (step S118: No), the control unit stops the operation of the road surface heating system 10 (step S111). , The process ends.

On the other hand, if the outside air temperature _{T A} ≦ reference outside air temperature _{T A4} or road surface temperature _{T R} ≦ reference road surface temperature _{T R4} (step S118: Yes), the road surface temperature _{T R} is 0 ° C. (first switching reference road surface temperature) below It is determined whether there is any (step S119). If the road surface temperature _{T R} is higher than 0 ° C. (Step S119: No), and continues the low temperature heating operation returns to step S116, sequentially executes the subsequent processing. If the road surface temperature _{T R} is 0 ℃ or less (step S119: Yes), switch to the high temperature heating operation from the low temperature heating operation (step S120).

After switching to the high temperature heating operation, the water content W of the road surface in the heating target area 13 is detected by the environment detection device 16 and it is determined whether or not the detected water content W is larger than the reference water content W ₁ (step). S121). When the water content W is equal to or less than the reference water content W ₁ (step S121: No), the control unit stops the operation (step S111) and ends the process.

If the detected water amount W exceeds the reference water amount _{W 1} (step S121: Yes), the environment detection unit 16 detects the surface temperature _{T R,} the detected road surface temperature _{T R} is a predetermined reference road surface temperature _{T R5} It is determined whether or not the above (step S122).

When the road surface temperature T _R is lower than the reference road surface temperature T _R5 (step S122: No), the process returns to step S120, the high temperature heating operation is continued, and the subsequent processes are sequentially executed.

On the other hand, when the road surface temperature T _R is equal to or higher than the reference road surface temperature T _R5 (step S122: Yes), the high temperature heating operation is switched to the low temperature heating operation, the process flow is returned to step S116, and the subsequent processes are sequentially executed. The process is automatically executed until the operation is stopped.

In the road surface heating system 10 described above, the circuit through which the heat exchange medium flows can be switched between the first heating circuit and the second heating circuit according to the environmental condition at the time of detection by the environment detection device 16. The low temperature heating operation of directly heating the heating target region 13 by the sewage heat using the first heating circuit and the sewage heat using the heat pump H by the second heating circuit according to the snowfall condition and the like. It is possible to switch to the high temperature heating operation of heating the heating target region 13 at a higher temperature. As a result, from the detection result of the environment detection device 16, when heating for snow melting and freezing prevention is sufficient at a low temperature, switching to the low-temperature heating operation is performed to eliminate the amount of electric power for operating the heat pump and to flow through the sewer pipe 11. Energy saving can be achieved by using the thermal energy of the fluid as a heat source. In addition, when the heating temperature required in the heating target region 13 is high, it is possible to switch to the high temperature heating operation and use the sewage heat in the heat pump H as a heat source. Accordingly, when the load for snow melting is large, such as when the amount of snowfall is large, it is possible to appropriately heat the road surface with high thermal energy while suppressing the power consumption of the heat pump H to prevent snow melting and freezing. ..

Further, the environment detection device 16 detects the outside air temperature T _A , the road surface temperature T _R , the presence or absence of snowfall, and the water content W that cause snowfall or road surface freezing, and the snowfall or the like is prevented based on the detection result. Since the operation can be switched as described above, it is possible to appropriately perform snow melting and freeze prevention according to the surrounding environment.

Furthermore, at the start of operation when it is estimated that the heating temperature in the heating target region 13 may be lower, the road surface heating system 10 is provided by performing the preheating operation in which the circulation of the heat exchange medium is intermittently performed in the first heating circuit. The power saving effect of can be further enhanced. Further, based on the change of the outside air temperature T _A and surface temperature T _R after preheating operation, by selecting whether to stop the preheating operation, or heating at high switching to continuous low temperature heating operating temperature, road surface conditions And heating control suitable for the surrounding environment can be executed. In the road surface heating system 10 described above, when step S114 is Yes, the continuous low temperature heating operation may be performed regardless of the presence or absence of snowfall (that is, without passing through step S115).

Moreover, since the expansion tanks 32 and 42 are provided in the heat source side circulation path 30, the load side circulation path 40, and the direct connection circulation path 50, respectively, the temperature of the heat exchange medium changes greatly due to the switching of the operation. Even if the volume of the heat exchange medium changes, the expansion tanks 32 and 42 can allow the volume change.

The heat pump H may be configured to include a changeover switch that switches the circulation direction of the refrigerant to switch between heating and cooling on the load side. In such a case, the road surface heating system 10 can be used not only for snow melting in winter, but also for road surface cooling in summer. That is, in general, in the summer, the temperature of the sewage flowing through the sewer pipe 11 is lower than the temperature of the road surface of the cooling target region heated by the sun (that is, the heating target region 13 in the winter), and thus the first heating is performed. By performing the operation by the circuit, the road surface in the cooling target area can be cooled. In addition, by switching to the second heating circuit and performing the operation of reversely circulating the refrigerant in the heat pump H, the heat exchange medium is cooled in the load side heat exchanger 26 of the heat pump H, and is cooled at a lower temperature. The target area can be cooled.

Next, an example of control in the case of cooling the road surface to be the cooling target area (heat exchange target area) in the summer by using the road surface heating system 10 described above will be described. FIG. 6 is a flowchart showing the operation of the controller when cooling the cooling target area. In the following description of the road surface cooling control, the first heating circuit will be referred to as a first heat exchange circuit, and the continuous operation using this first heat exchange circuit will be referred to as a first cooling operation. In addition, the second heating circuit is referred to as a second heat exchange circuit, and operation using this second heat exchange circuit (that is, operation in which the refrigerant of the heat pump H is circulated in the second heat exchange circuit in reverse circulation to that in winter) is performed. The operation performed) is referred to as a second cooling operation. The first cooling operation is an energy saving operation capable of achieving energy saving as compared with the second cooling operation in which the heat pump H is operated (that is, the normal operation).

When the control process starts, the control unit determines whether the road surface temperature T _R detected by the environment detection device 16 is equal to or higher than a predetermined summer first reference road surface temperature T _S1 (step S210).

If the road surface temperature _{T R} is the summer than the first reference road surface temperature _{T S1} (step S210: No), the control unit stops the operation of the road surface heating system 10 (step S211), and ends the process.

On the other hand, if the road surface temperature _{T R} is the first reference road surface temperature _{T S1} or summer (step S210: Yes), it starts the first cooling operation of the first heat exchange circuit (first operation) (step S212), The time t from the start of the first cooling operation is counted, and it is determined whether the time t has passed a predetermined time t _th1 (step S213).

When the time t has not passed the predetermined time t _th1 (step S213: No), the first cooling operation is continued (step S212). When the time t has passed a predetermined time _{t th1} (step S213: Yes), the road surface temperature _{T R} is determined whether a lower summer second reference road surface temperature _{T S2} more than the first reference road surface temperature _{T S1} summer Yes (step S214). The summer second reference road surface temperature T _S2 may be, for example, 1° C. to 3° C. lower than the summer first reference road surface temperature T _S1 .

When the road surface temperature T _R is _lower than the summer second reference road surface temperature T _S2 (step S214: No), the operation of the road surface heating system 10 is stopped (step S211) and the process ends. On the other hand, if the road surface temperature _{T R} is the summer second reference road surface temperature _{T S2} above (step S214: Yes), further, the road surface temperature _{T R} is higher in summer third reference than the first reference road surface temperature _{T S1} summer It is determined whether or not the road surface temperature is _{equal to} or higher than T _S3 (step S215). The third summer reference road surface temperature T _S3 can be set to, for example, a temperature that is higher than the first summer reference road surface temperature T _S1 by 4° C. or more.

Road surface temperature _{T R} is, if it is summer smaller than the third reference surface temperature _{T S3} (Step S215: No), and continues the first cooling operation returns to step S212.

On the other hand, if the road surface temperature _{T R} is the summer third reference surface temperature _{T S3} above (step S215: Yes), the switching from the first cooling operation to a second cooling operation (second operation) (step S216), the second The time t from the start of the cooling operation is counted, and it is determined whether the time t has passed a predetermined time t _th2 (step S217). The predetermined time t _th2 in step S217 may be the same value as the predetermined time t _th1 counted in step S213, or may be a different value.

When the time t has not passed the predetermined time t _th2 (step S217: No), the second cooling operation is continued (step S216). When the time t has passed a predetermined time _{t th2} (step S217: Yes), the road surface temperature _{T R} is determined whether the lower summer than the fourth reference surface temperature _{T S4} than the third reference surface temperature _{T S3} summer (Step S218). The summer fourth reference road surface temperature T _S4 can be set to a temperature higher than the summer first reference road surface temperature T _{S1 and} lower than the summer third reference road surface temperature T _S3 by 1 to 3° C., for example.

Road surface temperature _{T R} is, if it is summer fourth reference surface temperature _{T S4} or more (step S218: No), and continues the second cooling operation returns to step S216, sequentially executes the subsequent processing.

On the other hand, when the road surface temperature T _R is _lower than the summer fourth reference road surface temperature T _S4 (step S218: Yes), it is further determined whether or not the road surface temperature T _R is equal to or higher than the summer first reference road surface temperature T _S1. (Step S219).

When the road surface temperature T _R is equal to or higher than the summer first reference road surface temperature T _S1 (step S219: Yes), the second cooling operation is switched to the first cooling operation, the processing flow is returned to step S212, and the subsequent processing is sequentially performed. Execute. The process is automatically executed until the operation is stopped.

When the road surface temperature T _R is lower than the summer first reference road surface temperature T _S1 (step S219: No), the control unit stops the operation of the road surface heating system 10 (step S211) and ends the process.

In the road surface cooling control by the road surface heating system 10 described above, the circuit through which the heat exchange medium flows is divided into the first heat exchange circuit and the second heat exchange circuit according to the environmental condition (here, the road surface temperature) at the time when the environment detection device 16 detects. It is possible to switch to and from the heat exchange circuit. Specifically, in the summer when the road surface temperature is high, when the road surface temperature is relatively low, the first heat exchange circuit is used to directly cool the cooling target area by sewage heat, and the second cooling operation. It is possible to switch to the second cooling operation for cooling the cooling target area at a temperature lower than the sewage heat by using the heat pump H and the heat exchange circuit.

The cooling control shown in FIG. 6 is an example, and, for example, step S213 and/or step S217 may be omitted in the above-mentioned control. Further, in step S219, the second summer reference road surface temperature T _S2 may be used instead of the first summer reference road surface temperature T _S1 . Further, before starting the first cooling operation, a precooling operation in which circulation and stop of the heat exchange medium in the first heat exchange circuit are repeated may be performed.

The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention.

For example, the switching between the low temperature heating operation and the high temperature heating operation can be configured to be performed based on at least one of the outside air temperature T _A , the road surface temperature T _R, and the presence or absence of snowfall.

Further, the buried pipe is not limited to the sewer pipe 11, and may be a buried pipe such as a water supply pipe, an agricultural water pipe, or an industrial water pipe. The temperature of the water flowing through such a pipe does not fluctuate greatly throughout the year, and can be used as a high-temperature heat source in winter and a low-temperature heat source in summer.

Further, the heat collection pipe 12 which is the first heat exchange pipe may not be arranged on the outer peripheral surface or inside of the buried pipe such as the sewer pipe 11 and may be buried in the ground to collect the underground heat. Anything is possible. For example, a drilling machine such as a boring machine or an auger is used to drill a hole that extends almost vertically in the ground, and a heat collection pipe (first heat exchange pipe) is installed in this drilling hole in a posture that extends almost vertically. Good. As a result, the heat exchange medium flowing through the heat collection tube can exchange heat with the surrounding ground and the surrounding groundwater.

10 Road surface heating system 11 Sewer pipe (buried pipe)
12 Heat collection tube (first heat exchange tube)
13 Heating target area (heat exchange target area)
14 Radiator tube (second heat exchange tube)
16 environment detection device 30 heat source side circulation path (first circulation path)
32, 42 Expansion tank 40 Load side circulation path (second circulation path)
50 Direct connection circuit H heat pump

Claims (7)

A first heat exchange tube that is buried in the ground, and a second heat exchange tube that is buried in a heat exchange target area closer to the road surface than the first heat exchange tube. Heat exchange circuit of
A first circulation path for circulating the heat exchange medium to the first heat exchange tube and the heat source side heat exchanger of the heat pump; and a second circulation path to circulate the second heat exchange tube and the load side heat exchanger of the heat pump. A second heat exchange circuit forming two circulation paths;
An environment detection device for detecting the surrounding environment of the heat exchange target area,
A first operation in which the heat pump is stopped and circulation is performed by the first heat exchange circuit, and a heat pump is operated and circulation is performed by the second heat exchange circuit based on a detection result of the environment detection device. A control unit that can be replaced with the second operation,
A road surface heating system comprising: The road surface heating system according to claim 1, wherein the first heat exchange pipe is embedded in the ground and is disposed on an outer peripheral surface or inside of an embedded pipe through which a fluid flows. The environment detection device detects at least one of an outside air temperature around the heat exchange target area, a road surface temperature of the heat exchange target area, and presence or absence of snowfall in the heat exchange target area. The road surface heating system according to claim 1. The control unit performs a preheating operation in which the circulation and the stop of the heat exchange medium in the first heat exchange circuit are repeated at a predetermined cycle time when the operation is started. The road surface heating system according to item. The environment detection device detects the outside air temperature around the heat exchange target area and the road surface temperature of the heat exchange target area,
The control unit is
When the outside air temperature is equal to or lower than a predetermined first outside air temperature, or the road surface temperature is equal to or lower than a predetermined first road surface temperature, the preheating operation is started,
After starting the preheating operation,
While the operation is stopped when the outside air temperature exceeds a predetermined second outside air temperature higher than the first outside air temperature, or the road surface temperature exceeds a predetermined second road surface temperature higher than the first road surface temperature,
The first operation is continued when the outside air temperature is equal to or lower than a predetermined third outside air temperature lower than the first temperature, or when the road surface temperature is equal to or lower than a predetermined third road surface temperature lower than the first road surface temperature. 5. The road surface heating system according to claim 4, wherein the road surface heating system is performed in a general manner. The environment detection device detects the presence or absence of snowfall, the amount of water on the road surface in the heat exchange target area, and the road surface temperature of the heat exchange target area,
The control unit is
When there is snowfall, the detected water content exceeds a predetermined water content, and the detected road surface temperature is equal to or lower than a predetermined first switching reference road surface temperature, the first operation is switched to the second operation,
During the second operation, the detected water content exceeds the predetermined water content, and the detected road surface temperature is equal to or higher than a predetermined second switching reference road surface temperature higher than the first switching reference road surface. , Switch to the first operation,
The road surface heating system according to any one of claims 1 to 5, wherein the operation is stopped when the detected water content is equal to or less than the predetermined water content during the second operation. The road surface according to any one of claims 1 to 6, wherein at least the first circulation path and the second circulation path are provided with an expansion tank that allows a volume change of a heat exchange medium. Heating system.

Images