Unpowered self-heat exchange structure and method

Abstract

The application discloses a kind of unpowered self heat exchange structure and method, unpowered self heat exchange structure is breathable and heat-permeable anti-infiltration buried hole, the breathable and heat-permeable anti-infiltration buried hole is arranged at the bottom of underground reservoir, the breathable and heat-permeable anti-infiltration buried hole is laid breathable anti-infiltration sand, the upper surface of breathable anti-infiltration sand is contacted with water body in reservoir, the lower surface is contacted with soil under reservoir, and water body and soil exchange heat through breathable anti-infiltration sand.Unpowered self heat exchange method, water body in underground reservoir and soil under reservoir exchange heat through breathable anti-infiltration sand laid in breathable and heat-permeable anti-infiltration buried hole under reservoir.The application aims at the limitation of natural energy utilization for building heating in cold and water shortage areas such as north, and proposes a multipurpose rainwater energy pool, which combines sponge city construction and natural energy development, collects, purifies and stores rainwater and sewage, exchanges energy between stored water body and stratum soil, indirectly utilizes soil heat energy, and stores heat energy in water pool.

Description

Technical Field

[0001] This invention relates to the field of energy-saving technology, and more specifically, to a non-powered self-heating structure and method. Background Technology

[0002] Building energy consumption constitutes a significant portion of global energy consumption. According to the "China Building Energy Consumption Research Report (2017)," the energy consumed by buildings throughout their entire life cycle accounts for 40% to 50% of China's total energy consumption. In 2017, my country's total building energy consumption was 899 million tons of standard coal equivalent, accounting for 21.11% of the country's total energy consumption. Public buildings accounted for 38.33% of total building energy consumption, indicating high energy consumption indicators and large total volume. Compared to traditional energy sources such as coal and oil, heat pump technology is a renewable energy utilization technology with advantages such as economy, energy saving, and environmental protection. Water is the simplest and cheapest heat source; however, in northern China, such as Beijing, the development and utilization of groundwater resources are strictly prohibited, making it difficult to adopt water source heat pump technology and hindering its application in northern regions. Summary of the Invention

[0003] To address the above problems, this invention proposes a non-powered self-heating technology based on sponge city construction, using the water stored in the underground storage tank as the heat source for a water source heat pump, in order to improve the heat exchange efficiency between the water and soil in the underground storage tank.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] This invention provides a non-powered self-heating structure, which is a breathable, heat-permeable, and seepage-proof buried hole. The breathable, heat-permeable, and seepage-proof buried hole is located at the bottom of an underground water storage tank. Breathable and seepage-proof sand is laid inside the hole. The upper surface of the breathable and seepage-proof sand is in contact with the water in the water storage tank, and the lower surface is in contact with the soil. Heat exchange occurs between the water and the soil through the breathable and seepage-proof sand. The breathable (heat-permeable) seepage-proof sand has both air-permeable and heat-permeable functions as well as preventing water seepage.

[0006] The breathable, heat-permeable, and seepage-proof buried holes are spaced out at the bottom of the water storage tank.

[0007] The breathable, heat-permeable, and seepage-proof buried holes are evenly spaced at the bottom of the water storage tank.

[0008] The height of the permeable, heat-permeable, and seepage-proof buried hole is the same as the thickness of the bottom of the reservoir. The permeable, heat-permeable, and seepage-proof buried hole extends into the soil layer below the reservoir.

[0009] The walls and bottom of the reservoir are made of concrete and are non-permeable, heat-permeable, and seepage-proof buried boreholes.

[0010] The permeable and impermeable sand is deposited in the permeable and heat-permeable buried borehole, with a porosity of 0.3 to 0.4. No binder is used between the permeable and impermeable sands; they are deposited naturally.

[0011] The present invention also provides a non-powered self-heating method in which the water in the underground reservoir and the soil below the reservoir exchange heat through the permeable and heat-permeable seepage-proof sand arranged in the permeable and heat-permeable buried holes under the reservoir.

[0012] The permeable and impermeable sand is deposited in the permeable and heat-permeable buried borehole, with a porosity of 0.3 to 0.4.

[0013] The water in the underground reservoir exchanges heat with the soil beneath it mainly through gas flow.

[0014] In summer, when the water temperature in the reservoir is higher than the soil temperature, gases flow towards the soil, promoting heat transfer from the water to the soil; in winter, when the water temperature in the reservoir is lower than the soil temperature, gases flow towards the water, promoting heat transfer from the soil to the water.

[0015] Technical features (principles):

[0016] A permeable (heat-resistant) and seepage-proof buried borehole is installed beneath the reservoir. Utilizing the temperature difference, diffusion, and radiation effects between the soil, water, and gas, the system promotes gas flow, opening energy transfer channels between the soil and water. Through gas convection, it enhances heat exchange between the soil and water, achieving an effect equivalent to a ground-source heat pump. In summer, when the water temperature in the reservoir is higher than the soil temperature, gas flows towards the soil, promoting heat transfer from the water to the soil through convection. In winter, when the water temperature in the reservoir is lower than the soil temperature, gas flows towards the water, promoting heat transfer from the soil to the water through convection, equivalent to a ground-source heat pump. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a non-powered self-heating structure according to Embodiment 1 of the present invention.

[0018] Figure 2 This is a schematic diagram of a non-powered self-heating structure according to Embodiment 2 of the present invention. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0020] Example 1

[0021] This invention provides a non-powered self-heating structure, such as... Figure 1As shown, this is a permeable, heat-permeable, and seepage-proof buried borehole. These boreholes are located at the bottom of the underground reservoir 1, and permeable, seepage-proof sand 3 is laid inside them. The boreholes provide both air permeability and heat permeability while preventing water seepage. The permeable, seepage-proof sand 3 within the boreholes is formed naturally without any binder. The upper surface of the permeable, seepage-proof sand 3 is in contact with the water 4 in the reservoir 1, and the lower surface is in contact with the soil layer 2. The height of the permeable, heat-permeable, and seepage-proof buried boreholes can be set to match the thickness of the bottom of the reservoir 1. Figure 1 As shown, a silica sand honeycomb wellbore 5 is installed in the water storage tank 1 for water purification.

[0022] The accumulation structure formed by the breathable and seepage-proof sand 3 has many similarities to that of porous media. The heat transfer mode of the breathable, heat-permeable, and seepage-proof buried borehole can be analyzed with reference to the theory of porous media. Specifically, it manifests in the following ways:

[0023] (1) Heat transported through sand particles due to conduction;

[0024] (2) Heat transported through the gas due to conduction;

[0025] (3) Heat transported through the gas due to convection;

[0026] (4) Heat migration between sand particles is caused by radiation.

[0027] (5) Heat transported through the gas due to heat diffusion.

[0028] In a packed structure, the heat transfer process between the gas and solid phases is mainly convective heat transfer, while the heat transported by radiation and heat diffusion is relatively small. This calculation only considers the heat transported by conduction and convection.

[0029] The amount of heat transported by breathable and impermeable sand through conduction per unit time can be referenced by the following formula for the thermal conductivity of a flat plate:

[0030]

[0031] In the formula, Q represents the heat flow rate (in W) transferred from the high-temperature side to the low-temperature side.

[0032] λ—The thermal conductivity of the flat plate, W / (m·K);

[0033] F – Area of ​​the flat plate, in meters 2 ;

[0034] δ—plate thickness, m.

[0035] The effective thermal conductivity of the breathable, heat-permeable, and seepage-proof buried borehole can be referenced by the following empirical formula:

[0036] λ0=(1-n)λs +nλ f

[0037] In the formula, λ0 is the effective thermal conductivity of the breathable and impermeable sand, W / (m·K).

[0038] λ s —The thermal conductivity of sand particles is taken as 0.33 W / (m·K);

[0039] λ f —The thermal conductivity of the gas, taken as 2.51 × 10⁻⁶. -2 W / (m·K);

[0040] n—Porosity of the breathable and impermeable sand, generally 0.3 to 0.4, with a value of 0.35.

[0041] According to calculations, the effective thermal conductivity of the breathable, heat-permeable, and seepage-proof buried borehole is λ0 = 0.239 W / (m·K).

[0042] The amount of heat transported by the permeable, heat-permeable, and seepage-proof buried borehole per unit time through convection can be referred to by the following formula:

[0043] Φ=hA(T w -T f ) or Φ=hAΔT

[0044] In the formula, Φ represents the convective heat transfer flow rate in W.

[0045] A – The wall area in direct contact with the fluid, in meters (m²). 2 ;

[0046] ΔT—The temperature difference between the soil and the water in the reservoir, in °C;

[0047] h — Convection heat transfer coefficient, unit W / (m²) 2 The convective heat transfer coefficient of free air movement (natural convection) caused by temperature difference (℃) is 5–20 W / (m³). 2 ·℃), the value used in this calculation is 5W / (m³). 2 ·℃).

[0048] A 1000m² buried borehole with breathable, heat-permeable, and seepage-proof design. 2 Based on a depth of 0.3m and a temperature difference of 15℃, the heat transported per unit time due to thermal conduction is Q1 = 1.195kW; the heat transported due to convection is Q2 = 75kW.

[0049] Therefore, the total heat transported per unit time by the permeable, heat-permeable, and seepage-proof buried borehole is Q=Q1+Q2=76.195KW.

[0050] Comparing with the heat conduction of concrete, the heat transfer mode of concrete is flat plate heat transfer. The thermal conductivity of ordinary concrete is 1.28 W / (m·K). Under the same conditions, the heat conduction of concrete per unit time is Q′=6.4kW.

[0051] Under the same conditions, the heat transported by the breathable, heat-permeable, and seepage-proof buried borehole is about 12 times that of concrete.

[0052] Example 2

[0053] This invention provides a non-powered self-heating structure, namely, a breathable, heat-permeable, and seepage-proof buried borehole. This borehole is installed at the bottom of an underground water storage tank 1, and is lined with breathable and seepage-proof sand 3. The borehole provides both air permeability and heat permeability while preventing water seepage. The breathable and seepage-proof sand 3 within the borehole is formed naturally without any binder. The upper surface of the sand 3 is in contact with the water 4 in the water storage tank 1, and the lower surface is in contact with the soil layer 2. The borehole extends deep into the soil layer 2 at the bottom of the water storage tank 1. Figure 2 As shown.

[0054] The proportion and size of the permeable, heat-permeable, and seepage-proof buried holes at the bottom of the water storage tank 1 can be adjusted as needed and are not limited here.

[0055] It should be noted that various modifications can be made to the embodiments disclosed herein. Therefore, the embodiments disclosed in the specification should not be regarded as limitations on the present invention, but only as examples of embodiments, the purpose of which is to make the features of the present invention obvious.

[0056] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A non-powered self-heating structure, characterized in that, The non-powered self-heating structure is a permeable, heat-permeable, and seepage-proof buried hole. This hole is located at the bottom of an underground water storage tank. Permeable and seepage-proof sand is laid inside the hole. The upper surface of the sand is in contact with the water in the tank, and the lower surface is in contact with the soil beneath. Heat exchange occurs between the water and soil through the sand. The sand naturally accumulates within the hole without any binder, and its porosity is 0.3~0.

4. The effective thermal conductivity formula for the permeable and seepage-proof buried hole is as follows: ， In the formula, λ0 is the effective thermal conductivity of the breathable and impermeable sand, W / (m·K). λ s —The thermal conductivity of sand particles; λ f —The thermal conductivity of the gas; n —Porosity of breathable and impermeable sand.

2. The non-powered self-heating structure according to claim 1, characterized in that, The breathable, heat-permeable, and seepage-proof buried holes are spaced out at the bottom of the water storage tank.

3. The non-powered self-heating structure according to claim 1, characterized in that, The breathable, heat-permeable, and seepage-proof buried holes are evenly spaced at the bottom of the water storage tank.

4. The non-powered self-heating structure according to claim 1, characterized in that, The height of the breathable, heat-permeable, and seepage-proof buried hole is the same as the thickness of the bottom of the water storage tank.

5. The non-powered self-heating structure according to claim 1, characterized in that, The breathable, heat-permeable, and seepage-proof buried holes extend into the soil layer beneath the reservoir.

6. A non-powered self-heating method, characterized in that, The water in the underground reservoir exchanges heat with the soil beneath it through breathable, heat-permeable, and seepage-proof sand placed in permeable, heat-permeable, and seepage-proof buried holes at the bottom of the reservoir. This permeable, seepage-proof sand accumulates naturally within these holes without the use of binders, and has a porosity of 0.3-0.

4. Heat exchange between the water and soil primarily occurs through gas flow. In summer, when the water temperature is higher than the soil temperature, gas flows towards the soil, promoting heat transfer from the water to the soil. In winter, when the water temperature is lower than the soil temperature, gas flows towards the water, promoting heat transfer from the soil to the water. The effective thermal conductivity formula for the permeable, heat-permeable, and seepage-proof buried holes is as follows: ， In the formula, λ0 is the effective thermal conductivity of the breathable and impermeable sand, W / (m·K). λ s —The thermal conductivity of sand particles; λ f —The thermal conductivity of the gas; n —Porosity of breathable and impermeable sand.

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