CN104514218A - Energy pile and system thereof - Google Patents

Abstract

The invention relates to an energy pile, which includes a pile body and a heat exchange tube arranged inside the pile body, the pile body is arranged underground, and the pile body is made of cement, fly ash and gravel The composite body is formed, and the heat exchange tube forms a heat conduction path inside the pile body.

Description

Energy pile and its system

technical field

The invention relates to the field of pile foundation engineering, in particular to an energy pile and a system thereof.

Background technique

Pile foundation refers to a deep foundation consisting of piles and pile caps connected to the top of the piles. Pile foundations have the characteristics of high bearing capacity and small settlement, and are widely used in projects with various geological conditions, especially when building heavy buildings on weak foundations. According to the classification of materials, pile foundations can be divided into steel piles, reinforced concrete piles, steel pipe concrete piles, cement fly-ash gravel piles (Cement Fly-ash Gravel pile, CFG composite piles) and so on.

The energy pile is to implant an underground heat exchange pipeline system in the pile foundation, use it to obtain shallow geothermal energy from the stratum, make full use of the good thermal conductivity of concrete, and form a heat exchange element with the surrounding earth. The research and engineering application of energy piles at home and abroad are mainly aimed at large-diameter reinforced concrete pile foundations.

However, the cost of reinforced concrete pile foundation with large diameter is high and the construction speed is slow, while the pile diameter of CFG composite pile is small (350-600mm). Embedding heat exchange tubes in CFG composite piles is of great significance for promoting the use of environmentally friendly ground source heat pump systems in northern China, including Beijing.

Contents of the invention

In view of this, it is indeed necessary to provide an energy pile based on a CFG composite pile and a system thereof.

An energy pile, which includes a pile body and a heat exchange tube arranged inside the pile body, the pile body is arranged underground, and the pile body is a composite material composed of cement, fly ash and gravel body, and the heat exchange tube forms a heat conduction path inside the pile body.

An energy pile system, which includes an energy pile, a surface heat pipe, and a ground source heat pump machine, the ground source heat pump machine is connected to the energy pile through the surface heat pipe, and the energy pile includes a pile body and a set The heat exchange tube inside the pile body, the pile body is a composite body composed of cement, fly ash and gravel, the heat exchange tube is connected with the surface heat pipe and inside the pile body A thermal circuit is formed between the ground source heat pump and the ground source heat pump.

Compared with the prior art, the present invention realizes the heat exchange between the underground energy source and the surface building by arranging the heat exchange tube in the CFG composite pile, the extra engineering cost is less, no need to occupy additional underground space, and the outdoor unit or Cooling tower, with good heat transfer effect, can save energy by 30% to 50% compared with traditional air conditioning system. At the same time, because the energy pile 10 closely combines the underground heat exchange tube 102 with the CFG composite pile, the stability and durability of the energy pile system are guaranteed, and the cost is lower than that of the general underground buried pipe ground source heat pump system.

Description of drawings

Fig. 1 is a schematic structural diagram of the energy pile of the present invention.

2 to 5 are structural schematic diagrams of the heat exchange tubes of the present invention.

Fig. 6 is a schematic structural view of the stent of the present invention.

Fig. 7 is a schematic structural diagram of the energy pile and the ground source heat pump system of the present invention.

Fig. 8 is a test chart of the outlet water temperature of the energy pile according to the present invention when the inlet water temperature is 5°C.

Fig. 9 is a test chart of the outlet water temperature of the energy pile according to the present invention when the inlet water temperature is 35°C.

Description of main component symbols

Energy pile 10 Pile 101 heat exchange tube 102 main tube 103 Connector 104 bracket 105 Metal strips 106 Stirrup 107 Protection board 108 surface heat pipe 20 Ground source heat pump 30

The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings.

Detailed ways

The energy pile provided by the embodiment of the present invention will be further described below in conjunction with the accompanying drawings.

Please refer to FIG. 1 , which is an energy pile 10 provided by an embodiment of the present invention. The energy pile 10 includes a pile body 101 and a heat exchange tube 102 . The heat exchange tube 102 is disposed inside the pile body 101 .

The pile body 101 is arranged underground. The pile body 101 is a compound composed of cement, fly ash and gravel. The shape of the pile body 101 is set according to specific needs, and can be a square column, a cylinder or other geometric shapes. In this embodiment, the pile body 101 is a cylinder.

Please refer to Fig. 1 to Fig. 5, described heat exchange pipe 102 can be single U type, double U series type, double U parallel type, triple U type and double W type, and described heat exchange pipe 102 is in described pile body 101 A thermal conduction path is formed inside. Specifically, the heat exchange tube 102 includes a plurality of main body tubes 103 and a plurality of connection heads 104 . Two adjacent main body tubes 103 of the plurality of main body tubes 103 are connected by the connection head 104 to form a "U" shape, so that the plurality of main body tubes 103 integrally form a heat conduction path. In this embodiment, the heat exchange tubes 102 are of double U series type.

The material of the heat exchange tube 102 is polyethylene, high density polyethylene and the like. The diameter of the main body pipe 103 ranges from 19 mm to 38 mm. The connecting head 104 is a U-shaped connecting pipe. The diameter of the connecting head 104 matches the diameter of the main pipe 103 to ensure that the connecting head 104 is tightly connected to the main pipe 103 and the main pipe 103 forms a heat conduction path. In this embodiment, the material of the heat exchange tube 102 is high-density polyethylene, wherein the diameter of the main tube 103 is 25 mm, and the main tube 103 is connected to the connecting head 104 by hot melting. It can be understood that the materials of the heat exchange tubes 102 are not limited to those mentioned above, and may also be other heat-resistant materials used in the construction field.

The heat exchange tube 102 is buried inside the pile body 101, and the end of the pile body 101 that goes deep into the ground is spaced apart from the heat exchange tube 102, so as to ensure the connection between the heat exchange tube 102 and the pile body 101. The bottoms are not in contact, thereby effectively avoiding damage to the heat exchange tube 102 and reduction in heat exchange efficiency. It can be understood that the heat exchange tube 102 can extend to the outside of the pile body 101 to realize heat exchange with the outside.

The energy pile 10 may further include a bracket 105 disposed around the heat exchange tube 102 . The heat exchange tube 102 is supported by the bracket 105 and is disposed inside the pile body 101 together with the bracket 105 . Please refer to FIG. 6 , the bracket 105 includes a plurality of metal strips 106 and a plurality of stirrups 107 interwoven to form a grid structure. The plurality of metal strips 106 are arranged in parallel and spaced apart to form a columnar body. The plurality of stirrups 107 tightly bind the plurality of metal strips 106 to form an integral bracket 105 . In this embodiment, the bracket 105 includes a plurality of steel bars and stirrups, and the heat exchange tube 102 and the bracket 105 can be bound together by a cable tie. The heat exchange tube 102 is fixed by the bracket 105 to protect the heat exchange tube 102 . In addition, the bracket 105 can further improve the mechanical strength of the energy pile 10 .

Further, the energy pile 10 may include at least one protection board 108 . The protective plate 108 is disposed on the bottom of the bracket 105 . The bottom of the bracket 105 refers to the deepest part where the bracket 105 is buried in the pile body 101 . Specifically, the protection plate 108 is arranged under the connector 104 of the heat exchange tube 102 to protect the connector 104 and avoid Damage may occur. The protective plate 108 can be angle steel or the like. In this embodiment, the protective plate 108 is an angle steel. It can be understood that the material of the protection board 108 can also be other commonly used protection materials in buildings.

The specific construction steps of the energy pile 10 are as follows: first, the heat exchange tube 102 is fixed to the bracket 105, and the joint 104 of the heat exchange tube 102 is protected with an angle steel; then the bundled heat exchange tube 102 is quickly placed in the pile body 101. Wherein, the connecting head 104 can be fixed to the angle steel to better protect the connecting head 104 .

It can be understood that the heat exchange tube 102 may not be fixed by the bracket 105 and protected by the angle steel, but may be directly buried in the pile body 101 to form an integral structure with the pile body 101 .

Please refer to FIG. 7 , the present invention also provides an energy pile system, which includes an energy pile 10 , a surface heat pipe 20 and a ground source heat pump 30 . The energy pile 10 is connected to the ground source heat pump machine 30 through the surface heat pipe 20 . The surface heat pipe 20 is connected to the heat exchange pipe 102, and a heat conduction circuit is formed between the inside of the pile body 101 and the ground source heat pump machine 30, so as to jointly realize heat exchange for the building. The material and shape of the surface heat pipe 20 are the same as the heat exchange pipe 102 . The heat exchange pipe 102 and the surface heat pipe 20 are filled with an exchange liquid (not shown). The exchange fluid includes water, salt water and antifreeze. In this embodiment, the exchange liquid is water. In winter, the exchange fluid passing through the heat exchange tubes 102 extracts the heat in the shallow soil layer, and the exchange fluid is circulated through the ground source heat pump 30 to finally supply heat to the building. In summer, the heat of the building is extracted, and the heat is released into the shallow soil layer through the circulation of the exchange liquid in the heat exchange tube 102 .

The heat transfer effect of the energy pile system can be evaluated by the thermal power per linear meter. The formula for calculating the thermal power q per linear meter is q=(C×m×ΔT)/H, where q is the thermal power per linear meter in W/m; C is the specific heat capacity of the exchange fluid in J/(kg ?°C); m is the mass flow rate of the exchange fluid, in kg/s; ΔT is the difference obtained by subtracting the outlet temperature from the inlet water temperature of the exchange fluid, in °C; H is the heat exchange tube 102 in the pile body 101 depth, in m.

In this embodiment, please refer to FIG. 8 , an exchange fluid with a temperature of 5° C. is provided to the energy pile 10 to simulate a winter environment. After a period of time, the temperature of the exchange fluid can be kept above 7° C. In this embodiment, the mass flow rate of water is 0.167 kg/s, and the depth of the heat exchange tube in the pile body is 18 meters. At this time, the calculated thermal power per linear meter is basically greater than 60 watts per meter. Referring to FIG. 9 , an exchange fluid with a temperature of 35° C. is provided to the energy pile 10 to simulate a summer environment. After a period of time, the temperature of the exchange fluid can be maintained at about 30° C. In this embodiment, the mass flow rate of water is 0.167 kg/s, and the depth of the heat exchange tube in the pile body is 18 meters. At this time, the calculated thermal power per linear meter is greater than 120 watts per meter.

The invention realizes the heat exchange between the underground energy source and the surface building by arranging the heat exchange tube in the CFG composite pile, the additional engineering cost is small, no additional underground space is required, the outdoor unit or the cooling tower can be omitted, and the heat transfer effect is excellent. Good, 30% to 50% energy saving than traditional air conditioning systems. At the same time, because the energy pile 10 closely combines the underground heat exchange tube 102 with the CFG composite pile, the stability and durability of the energy pile system are guaranteed, and the cost is lower than that of the general underground buried pipe ground source heat pump system.

In addition, those skilled in the art can also make other changes within the spirit of the present invention. Of course, these changes made according to the spirit of the present invention should be included in the scope of protection claimed by the present invention.

Claims (9)

1. an energy pile, it comprises the heat exchanger tube that a pile body and is arranged at the inside of described pile body, described pile body is arranged at underground, and described pile body is the complex be made up of cement, flyash and rubble, and described heat exchanger tube forms a thermal conducting path in described pile body inside.

2. energy pile as claimed in claim 1, is characterized in that, described heat exchanger tube be singly U-shaped, double-H groove weld tandem type, double-H groove weld parallel connection type, three U-shaped or two W types.

3. energy pile as claimed in claim 1, it is characterized in that, described heat exchanger tube comprises multiple main body tube and multiple connector, and described multiple main body tube and described multiple connector are interconnected to form at least one thermal conducting path.

4. energy pile as claimed in claim 3, it is characterized in that, described connector is U-shaped tube connector.

5. energy pile as claimed in claim 1, it is characterized in that, comprise a support further, described heat exchanger tube by described stent support, and is arranged at the inside of described pile body together with described support.

6. energy pile as claimed in claim 5, it is characterized in that, described support comprises multiple bonding jumper and multiple stirrup weaves formation one space truss structure mutually.

7. energy pile as claimed in claim 5, it is characterized in that, comprise at least one guard shield further, described guard shield is arranged at the bottom of described support, and described guard shield is angle steel.

8. energy pile as claimed in claim 1, is characterized in that, it is outside that described heat exchanger tube extends described pile body.

9. an energy pile system, it comprises an energy pile, an earth's surface heat pipe and an earth source heat pump machine, by earth's surface heat pipe, described earth source heat pump machine is connected with described energy pile, described energy pile comprises the heat exchanger tube that a pile body and is arranged at the inside of described pile body, described pile body is the complex be made up of cement, flyash and rubble, and described heat exchanger tube is connected with described earth's surface heat pipe and forms a heat conduction loop between described pile body inside and earth source heat pump machine.