Energy efficiency improving system for shallow ground heat exchanger

Abstract

The utility model discloses an energy efficiency improving system for a shallow buried pipe heat exchanger. A closed or semi-closed heat storage area unit is arranged in a surrounding mode through area heat insulation plates. The heat storage area unit comprises a plurality of heat storage wells, a plurality of shallow water lifting wells, a plurality of deep water lifting wells, a plurality of solar water heaters, a heat storage water tank, a plurality of U-shaped vertical buried pipes and a ground source heat pump machine room; the buried depth of the regional heat insulation plate is arranged in soil of an earth crust constant temperature zone and penetrates through an earth crust daily variable temperature zone and an earth crust annual variable temperature zone from top to bottom, the buried depth H of the regional heat insulation plate is larger than or equal to H2 + 0.5-1 m, and H2 is the depth of the annual variable temperature zone; the heat storage well is of an inner and outer sleeve type hollow structure provided with a plurality of horizontal branch pipes shaped like a cross or a Chinese character'jing ', and the horizontal branch pipes are arranged in soil of a crustal annual variable temperature zone and a constant temperature zone. The buried depth H of the upper horizontal branch pipe is greater than or equal to H1 + 0.5-1m, and the buried depth H of the lower horizontal branch pipe is greater than or equal to H2 + 0.5-1m; h1 is the daily variable temperature zone depth, and H2 is the annual variable temperature zone depth.

Description

TECHNICAL FIELD

[0001] The utility model belongs to renewable clean energy utilization technical field, especially relates to a shallow ground heat exchanger energy efficiency improvement system. BACKGROUND

[0002] Geothermal energy as a kind of renewable clean energy is widely applied and popularized, but is influenced by factors such as region, climate environment, shallow crust geothermal field, underground aquifer, there is certain limitation in the popularization and application of shallow U-type vertical ground heat exchanger heat pump heating technology.

[0003] Due to the zonation phenomenon of shallow crust geothermal field, from top to bottom, it is divided into temperature variation zone, constant temperature zone and temperature increasing zone, the daily temperature variation zone depth in northern region of our country is only 1m~2m, the annual temperature variation zone depth can reach 15m~20m, the constant temperature zone depth is mostly underground 20~30m, and the temperature increasing zone depth is mostly above 30m.

[0004] Underground aquifer refers to those rocks or soil layers in the crust that can store and flow underground water, usually located several meters to tens of meters below the ground surface, with certain thickness, permeability and flowability, the position of aquifer mostly presents stratified structure, according to its physical properties and geological conditions, it can be divided into three types of impermeable layer, semi-permeable layer and permeable layer.

[0005] When heating in winter, the water in U-type vertical ground heat exchanger absorbs the heat in temperature increasing zone soil, the temperature of water increases, releases heat when flowing through shallow crust daily temperature variation zone and annual temperature variation zone, and the water temperature gradually decreases, resulting in that the water temperature entering the ground source heat pump unit decreases, and the unit heating COP value decreases by about 5~10%. Especially in cold and severe cold regions, the above problems are particularly prominent, the unit inlet water temperature is greatly influenced by temperature variation zone soil, because the heat extraction in winter is greater than the cold extraction in summer, the heat energy interaction between ground heat exchanger system and underground soil for a long time, after the ground source heat pump system is used for a period of time, the temperature of soil changes greatly, the soil cannot provide enough heat and temperature for heat transfer with ground heat exchanger system, local "cold accumulation" phenomenon occurs, so that the subsequent heat exchange effect of ground source heat pump system is poor, the heating effect in winter is poor, and even the system cannot operate normally, other heat sources need to be used to ensure the reliable and stable operation of the system. Therefore, the local "geothermal imbalance" problem is the main technical obstacle affecting the application and popularization of ground source heat pump technology.

[0006] Therefore, for those skilled in the art, designing a shallow U-type vertical ground heat exchanger energy efficiency improvement system or method can improve the heat exchange efficiency of U-type vertical ground heat exchanger in shallow crust temperature variation zone soil and the inlet water temperature of ground source heat pump unit, so as to solve the local "geothermal imbalance or cold accumulation" problem, which is a technical problem to be solved by those skilled in the art. CONTENT OF THE UTILITY MODEL

[0007] In order to solve the problems in the prior art, the shallow ground heat exchanger energy efficiency improving system has the following beneficial effects.

[0008] In order to achieve the above technical purpose, the utility model adopts the following scheme:

[0009] The shallow ground heat exchanger energy efficiency improving system is characterized in that a closed or semi-closed heat storage area unit is surrounded by the regional heat insulation plate, so that the soil or heat storage layer in the crust temperature change zone is passively heat stored to improve the heat exchange efficiency of the U-shaped vertical ground heat exchanger in the crust daily temperature change zone and annual temperature change zone.

[0010] The heat storage area unit comprises a plurality of heat storage wells, a plurality of shallow water pumping wells or recharge wells, a plurality of deep water pumping wells or recharge wells, a plurality of solar water heaters, a heat storage water tank, a plurality of U-shaped vertical ground heat exchangers, a water pumping pump, a circulating pump, a water pumping pipeline, a recharge pipeline, a water conveying pipeline and a ground source heat pump machine room.

[0011] The regional heat insulation plate is arranged at the periphery of the U-shaped vertical ground heat exchanger heat exchange area, is annular or square connection structure, and is used for preventing heat exchange or transmission between the U-shaped vertical ground heat exchanger and external soil.

[0012] The regional heat insulation plate is arranged in the crust constant temperature zone soil, penetrates the crust daily temperature change zone and annual temperature change zone from top to bottom, and the buried depth H is greater than or equal to H2+0.5-1m (H2 is the annual temperature change zone depth).

[0013] The heat storage well is a hollow structure with an inner sleeve and an outer sleeve, and the horizontal branch pipes are arranged in the crust annual temperature change zone and constant temperature zone soil; the upper horizontal branch pipe has a buried depth H greater than or equal to H1+0.5-1m, and the lower horizontal branch pipe has a buried depth H greater than or equal to H2+0.5-1m (H1 is the daily temperature change zone depth, and H2 is the annual temperature change zone depth).

[0014] The heat storage well horizontal branch pipe is provided with a heat storage cylinder, and the heat storage cylinder is provided with phase change heat storage materials.

[0015] The water taking and recharging depths of the several water pumping wells and recharging wells are arranged in multiple steps in a layered manner, and are divided into shallow water pumping wells or shallow recharging wells, deep water pumping wells or deep recharging wells; the shallow water pumping wells and the shallow recharging wells have the same depth, and the deep water pumping wells and the deep recharging wells have the same depth, and the purpose of such structural arrangement is to ensure water taking and recharging in the same layer to avoid cross contamination of water quality and soil in different underground water layers;

[0016] The solar water heater is a light pipe, flat plate or groove type solar water heater collector.

[0017] The heat storage water tank is provided with phase change heat storage materials.

[0018] The heat storage water tank is provided with an interface connected with the cold water pipe and the hot water pipe of the solar water heater, and the heat transfer and heat storage are completed through the circulating pump, the cold water pipe and the hot water pipe.

[0019] The heat storage water tank is provided with an interface connected with the heat storage outflow pipe and the heat storage return pipe of the heat storage well, and the heat transfer and heat storage of the heat storage well are completed through the water pumping pump, the heat storage return pipe and the heat storage outflow pipe.

[0020] The several U-shaped vertical ground heat exchanger pipes include U-shaped return water vertical pipes and U-shaped outflow vertical pipes, and are connected to the inside of the ground source heat pump machine room through the horizontal return water pipes and the horizontal inflow pipes and the main pipes.

[0021] Preferably, the water taking and recharging positions of the shallow water pumping wells and recharging wells are arranged in the temperature variation zone or the constant temperature zone of the water-containing soil layer within 15-30m from the ground.

[0022] Preferably, the water taking and recharging positions of the deep water pumping wells and recharging wells are arranged in the temperature increasing zone of the water-containing soil layer below 30-100m from the ground.

[0023] Preferably, the water taking and recharging positions of the water pumping wells and recharging wells are arranged in different water-containing soil layers in multiple steps, and the gradient height is determined according to the thickness of the pressure-bearing layer or the impermeable layer, and the gradient height is greater than 15-20m.

[0024] Preferably, the phase change temperature of the phase change heat storage materials in the heat storage well is 30-40℃.

[0025] Preferably, the phase change temperature of the phase change heat storage materials in the heat storage water tank is 70-80℃.

[0026] The utility model discloses beneficial effect is: the utility model discloses through setting up vertical heat insulation board, heat storage well in the diurnal temperature change zone soil and annual temperature change zone soil, not only effectively improve shallow soil and aquifer temperature in the diurnal temperature change zone of earth's crust, still effectively improve the heat exchange efficiency of U type vertical ground -buried pipe in the temperature change zone, reduce or eliminate " geothermal imbalance or cold accumulation " phenomenon, thereby improve ground source heat pump unit heating COP value and the operation stability of system, reach energy -conserving, high -efficient, low carbon, environmental protection requirement. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is shallow layer earth's crust soil structure section schematic view for the utility model embodiment system structure and;

[0028] Figure 2 It is heat storage well elevation structure schematic view for the utility model;

[0029] Figure 3 It is heat storage well, promotes the schematic diagram of layout of elevation view of recharging well, U type vertical ground -buried pipe for the utility model;

[0030] In the drawing: 1. regional heat insulation board, 2, shallow water well, 3, recharging pipeline, 4, heat storage well, 5, heat storage outlet pipe, 6, solar water heater, 7, cold water pipe, 8, hot water pipe, 9, heat storage return pipe, 10, circulating pump, 11, deep water well, 12, heat storage water tank, 13, heat coupling return pipe, 14, heat coupling supply pipe, 15, ground source heat pump machine room, 16, user side supply pipe, 17, user side return pipe, 18, diurnal temperature change zone soil, 19, annual temperature change zone soil, 20, constant temperature zone soil, 21, water pump, 22, U type vertical ground -buried pipe, 23, regulating valve, 24, heat storage cylinder, 25, phase change heat storage material, 41, horizontal branch pipe, 42, heat storage well vertical pipe, 43, flow equalizing orifice plate, 44, casing upper cover, 45 inner tube upper cover, 46, inner tube lower cover, 47, casing lower cover, 48, flower eye hole, 411, branch pipe outer sleeve, 412, branch pipe inner sleeve, 413, outer plugging plate, 421, outer sleeve vertical pipe, 422, inner vertical pipe, 423, branch pipe inner plugging plate. DETAILED DESCRIPTION

[0031] The following specific embodiments are described in detail, and the person skilled in the art can easily understand other advantages and effects of the utility model from the content disclosed in the specification; but it should be pointed out that the following specific embodiments do not technically limit the technical solutions, and the person skilled in the art can further extend the technology under the guidance of the following technical solutions. The protection scope of the patent application is subject to the claims.

[0032] The basic theory of the embodiment 1 is: through setting the heat insulation structure, the heat exchange between the inner and outer soil of the "heat island" is prevented; the heat storage well system is used for heat storage, the passive heat exchange of the soil storage layer in the "heat island" is forced; the multi-stage gradient shallow and deep water lifting or recharge well forced heat exchange technology is used, the passive forced heat exchange area of the "heat island" is increased, the water head difference of the runoff water in the upstream and downstream soil is increased, the groundwater runoff speed V=KI (V is the flow speed, K is the permeability coefficient, and I is the water slope) is increased, the groundwater in the soil temperature zone or constant temperature zone is penetrated from the upstream to the downstream through the U-shaped vertical ground heat exchanger 22, the heat exchange performance of the U-shaped vertical ground heat exchanger 22 is increased, and the COP value of the ground source heat pump unit is improved.

[0033] As shown in Figure 1 The embodiment 1 comprises a plurality of regional heat insulation plates 1, a plurality of shallow water lifting wells or recharge wells 2, a plurality of heat storage wells 4, a plurality of solar water heaters 6, a circulating pump 10, a deep water lifting well 11, a heat storage water tank 12, a ground source heat pump machine room 15, a user side water supply pipe 16, a user side return water pipe 17, a daily temperature zone soil 18, an annual temperature zone soil 19, a water lifting pump 21, a heat storage cylinder 24 and the like connected pipes and valves and the like parts. The regional heat insulation plate 1 is arranged at the periphery of the heat exchange area of the U-shaped vertical ground heat exchanger 22, and through the annular or square connecting structure, a closed or semi-closed heat storage area unit is surrounded, the soil in the earth temperature zone or the heat storage layer is passively stored heat to improve the heat exchange efficiency of the U-shaped vertical ground heat exchanger 22 in the daily temperature zone and the annual temperature zone of the earth. The solar water heater 6 is a light pipe, a flat plate or a groove type solar water heater.

[0034] The heat storage area unit is provided with a plurality of heat storage wells 4, a plurality of shallow water lifting wells 2, a plurality of deep water lifting wells 11, a plurality of solar water heaters 6, a heat storage water tank 12, a plurality of U-shaped vertical ground heat exchangers 22, a water lifting pump 21, a circulating pump 10, a recharge pipe 3 and a ground source heat pump machine room 15; since the recharge pipe 3 is arranged in the shallow water lifting well 2 and the deep water lifting well 11, the shallow water lifting well 2 and the deep water lifting well 11 are both water lifting wells and recharge wells.

[0035] Preferably, the water lifting and recharge water positions of the shallow water lifting well 2 and the shallow recharge well are arranged in the annual temperature zone soil 19 or the constant temperature zone soil 20 within 15-30 m from the ground;

[0036] Preferably, the water lifting and recharge water positions of the deep water lifting well 11 and the deep recharge well are arranged in the temperature increasing zone water-containing soil layer within 30-120 m from the ground;

[0037] Preferably, the shallow water well 2 and the deep water well 11 are set in a multi-level stepped manner for water intake and recharge, and the gradient height is determined according to the thickness of the confined layer or impermeable layer in different underground water-bearing soil layers, and the gradient height is greater than 15-20m.

[0038] The shallow diurnal temperature zone soil 18, annual temperature zone soil 19, and part of the constant temperature zone soil 20 where the U-shaped buried heat exchanger 22 is located are surrounded by a regional insulation board 1 to create a closed or semi-closed heat storage area unit. This allows the diurnal temperature zone soil 18 and annual temperature zone soil 19 of the earth's crust to form a heat storage layer, passively storing heat to improve the heat exchange efficiency of the heat storage area unit where the U-shaped vertical buried pipe 22 is located. This design sets the soil within a certain depth range of the local U-shaped vertical buried pipe 22 as a "thermal island" and prevents heat exchange between the soil inside and outside the "thermal island".

[0039] In this system, the thermal storage well system includes several thermal storage wells 4, thermal storage outlet pipes 5, solar water heaters 6, circulating pumps 10, hot water storage tanks 12, and valve components and connectors such as cold water pipes 7, hot water pipes 8, and thermal storage return pipes 9 connected to the solar water heaters. The heat extracted by the solar water heaters 6 is guided to the thermal storage wells 4 through the above components to achieve the supply of basic heat.

[0040] This embodiment also includes several shallow water lifting or recharge wells 2, deep water lifting or recharge wells 11, water pumps 21, and valve components and connectors such as water lifting or recharge pipelines 3 connected thereto; the buried depth of the regional insulation board 1 is set in the constant temperature zone soil 20, penetrating the daily temperature variation zone 18 and the annual temperature variation zone 19 of the earth's crust from top to bottom, and its buried depth H≥H2+0.5~1m, where H2 is the depth of the annual temperature variation zone soil 19.

[0041] The heat storage well 4 is a hollow structure with inner and outer sleeves, consisting of several horizontal branch pipes 41 arranged in a "+" or "well" shape. A lift pump 21 is installed at the bottom of the heat storage well 4. A heat storage cylinder 24 is installed inside each of the horizontal branch pipes 41. A phase change heat storage material 25 is installed inside the heat storage cylinder 24. The phase change temperature of the phase change heat storage material 25 inside the heat storage well 4 is 30–40°C.

[0042] The heat storage mechanism of the heat storage well is as follows: In summer and autumn, the hot water heated by the solar water heater 6 enters the hot water storage tank 12 through the circulation pump 10 and the corresponding pipes. Part of the heat is absorbed by the phase change heat storage material 25 set in the hot water storage tank 12, and part of the heat enters the heat storage well 4 through the hot water pipe 8 and the heat storage return pipe 9. The phase change temperature of the phase change heat storage material in the hot water storage tank 12 is 70-80℃.

[0043] The water taking and recharging depth of the several water wells or recharging wells is arranged in multiple levels in a ladder type, and is divided into shallow water wells 2 and deep water wells 11. It should be noted that the shallow water wells 2 and the deep water wells 11 are simultaneously provided with recharging pipelines 3, so that the depth of the water wells and the recharging wells can be arranged in the same structure. The purpose of the structure is to ensure water taking and recharging in the same layer, so as to avoid cross contamination of water quality and soil in different underground water layers.

[0044] The horizontal branch pipe 41 in the heat storage well is composed of a branch pipe outer sleeve 411 and a branch pipe inner sleeve 412. The distal end of the branch pipe outer sleeve 411 is provided with an outer sealing plate 413. The distal end of the inner sleeve 412 is provided with an inner sealing plate 423. The stand pipe 42 of the heat storage well is composed of an outer sleeve stand pipe 421 and an inner stand pipe 422. The bottom end of the outer sleeve stand pipe 421 is provided with a sleeve lower sealing plate 47 and a flower eye hole 48. The bottom end of the inner stand pipe 422 is also provided with an inner pipe lower sealing plate 46. The sleeve lower sealing plate 47 is provided with the flower eye hole 48.

[0045] The heat storage water tank 12 is provided with interfaces connected with the solar water heater 6, the cold water pipe 7 and the hot water pipe 8. The heat transfer and storage are completed through the circulating pump 10, the cold water pipe 7 and the hot water pipe 8. The heat storage water tank 12 is provided with interfaces connected with the heat storage well 4, the heat storage water outlet pipe 5 and the return water pipe 9. The heat transfer and storage of the heat storage well 4 are completed through the water taking pump 21, the heat storage return water pipe 9 and the heat storage water outlet pipe 5.

[0046] The heat storage water tank 12 is provided with the circulating pump 10, the heat coupling return water pipe 13, the heat coupling water supply pipe 14 and valve connecting components connected with the ground source heat pump machine room 15, which are used for combined heating of solar energy and geothermal energy.

[0047] The several U-shaped vertical ground buried pipes 22 contain return water pipes and water outlet pipes, which are connected to the inside of the ground source heat pump machine room 15 through horizontal return water pipes and horizontal water inlet pipes and main pipes.

[0048] Preferably, the regional heat insulation plate 1 can be a hollow heat insulation structure with adjustable height and can be detachable, and is arranged on the upstream and downstream sides of the underground aquifer in the "thermal island" area. When the ground source heat pump machine room 15 operates in the refrigeration working condition in summer, the regional heat insulation plate 1 loses the heat insulation and heat insulation functions, so as to ensure a higher refrigeration COP value of the ground source heat pump machine room 15.

[0049] Further, the recharging water level of the same layer water taking and recharging well is smaller than the water taking water level of the water well by 1-3 m, so as to facilitate the formation or increase of the runoff water head difference in the upstream and downstream soils of the U-shaped vertical ground buried pipe 22, increase the underground water runoff speed V, and improve the passive and intensified heat exchange effect of the U-shaped vertical ground buried pipe 22.

[0050] The U-shaped vertical buried pipe 22, the well for pumping water, the well for recharging, the well for storing heat, the water pumping or pressure boosting pump and the conveying pipeline connected with the water pumping or pressure boosting pump disclosed in the embodiment are all conventional technologies, and no more technical description is made herein; the horizontal buried pipe, the U-shaped vertical buried pipe 22 and the connecting member thereof are all made of PE or HDPE;

[0051] In the embodiment, the circulating pump 10 is a centrifugal pipeline pump, and the water pumping pump 21 is a submersible pump or a multi-stage centrifugal pump.

[0052] In conclusion, the utility model can effectively improve the temperature of the shallow soil and the aquifer in the crustal temperature zone, effectively improve the heat exchange efficiency of the U-shaped vertical buried pipe in the temperature zone, reduce or eliminate the phenomenon of “geothermal imbalance or cold accumulation”, thereby improving the heating COP value of the ground source heat pump unit and the operation stability of the system, and meeting the requirements of energy saving, high efficiency, low carbon and environmental protection.

Claims

1. A shallow buried pipe heat exchanger energy efficiency improvement system, characterized in that: A closed or semi-closed heat storage area unit is enclosed by a zone insulation panel. The aforementioned heat storage area unit includes several heat storage wells, several shallow water lifting wells, several deep water lifting wells, several solar water heaters, hot water storage tanks, several U-shaped vertical buried pipes, water transmission pipelines, and a ground source heat pump room. The aforementioned regional insulation board is buried in the constant temperature zone soil of the earth's crust, penetrating from top to bottom through the daily and annual temperature zones of the earth's crust, with a burial depth H≥H2+0.5~1m, where H2 is the depth of the annual temperature zone. The aforementioned thermal storage well is a hollow, inner and outer sleeve structure with several horizontal branch pipes arranged in a "+" or "well" shape. These horizontal branch pipes are located within the annual temperature variation zone or constant temperature zone soil of the Earth's crust. The upper horizontal branch pipe is buried at a depth H ≥ H1 + 0.5–1m, and the lower horizontal branch pipe is buried at a depth H ≥ H2 + 0.5–1m. H1 represents the daily temperature variation zone depth, and H2 represents the annual temperature variation zone depth. Phase change thermal storage materials are installed inside both the horizontal branch pipes and the thermal storage tank. The shallow pumping well and shallow reinjection well have the same depth, as do the deep pumping well and deep reinjection well. The water intake and reinjection locations of the shallow pumping well and shallow reinjection well are located within a water-bearing soil layer in the temperature variation zone or constant temperature zone within 15–30m of the ground surface.

2. The energy efficiency improvement system for a shallow buried pipe heat exchanger according to claim 1, characterized in that: The solar water heater is a bare tube, flat plate, or grooved solar water collector.

3. The energy efficiency improvement system for a shallow buried pipe heat exchanger according to claim 1, characterized in that: The hot water storage tank is equipped with an interface for connecting to the cold water pipe and hot water pipe of the solar water heater, and completes the heat transfer and storage through the circulation pump, cold water pipe and hot water pipe.

4. The energy efficiency improvement system for a shallow buried pipe heat exchanger according to claim 1, characterized in that: The hot water storage tank is equipped with an interface for connecting to the heat storage well, and the heat transfer and storage of the heat storage well are completed through a water pump, a heat storage return pipe, and a heat storage outlet pipe.

5. The energy efficiency improvement system for a shallow buried pipe heat exchanger according to claim 1, characterized in that: The aforementioned U-shaped vertical buried pipes include U-shaped return water risers and U-shaped outlet water risers, which are connected to the ground source heat pump room through horizontal return water pipes, horizontal inlet water pipes, and main pipelines, respectively.

6. The energy efficiency improvement system for a shallow buried pipe heat exchanger according to claim 1, characterized in that: The deep water extraction wells and deep recharge wells are located in the warming zone water-bearing soil layer 30 to 100 meters below the ground surface.

7. The energy efficiency improvement system for a shallow buried pipe heat exchanger according to claim 1, characterized in that: The shallow water extraction wells and shallow recharge wells, or deep water extraction wells and deep recharge wells, are located in multiple tiers within different water-bearing soil layers, with a gradient height greater than 15-20m.

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