Heating system for gradient utilization of terrestrial heat of rural residence

Abstract

The invention belongs to the technical field of new energy development and utilization, and particularly relates to a rural residence geothermal gradient utilization heating system which comprises a water collecting pump arranged in a water collecting well and used for collecting geothermal water in the water collecting well; the settling tower is communicated with the water outlet end of the water collecting pump and is used for filtering and settling the geothermal water collected by the water collecting pump; the inlet end of the flash evaporation heat exchange system is communicated with the settling tower, and the flash evaporation heat exchange system is used for circulating geothermal water and enabling the geothermal water to exchange heat with the cascade heat supply system; the cascade heat supply system is used for supplying heat to the indoor system by utilizing heat obtained by heat exchange with geothermal water; a water heater; the stepped heat supply system conducts heat preservation on the outdoor water pipe through heat obtained through heat exchange with geothermal water. The problems that the heat exchanger is seriously scaled, the heat exchange effect is invalid, even the heat exchanger is corroded and the temperature of recharged geothermal tail water is high due to the fact that existing geothermal heating is directly conducted through a plate heat exchanger can be solved.

Description

Technical Field

[0001] The invention belongs to the technical field of new energy development and utilization, and in particular relates to a heating system for rural residential geothermal cascade utilization. Background Art

[0002] Geothermal energy is the heat energy stored in the earth's interior. It is a clean, low-carbon, widely distributed, abundant, safe and high-quality renewable energy. Medium-deep geothermal energy mainly refers to the thermal energy resources contained in the strata within the range of 200 to 3,000 meters underground. Medium-deep geothermal energy is mainly developed in the hydrothermal type.

[0003] The development and utilization technologies of medium and low temperature geothermal energy include medium and low temperature geothermal power generation technology and medium and low temperature geothermal heating technology. The technologies suitable for medium and low temperature geothermal power generation include steam flash cycle, Kalina cycle power generation technology and organic Rankine cycle (ORC) power generation technology. The medium and low temperature geothermal heating technology is mainly hydrothermal geothermal heating technology. According to the different grades of hydrothermal temperature, it is divided into hydrothermal direct heating technology, hydrothermal plate exchange indirect heating technology and hydrothermal heat pump heating technology. In terms of energy utilization, the conventional geothermal cascade utilization, due to the maturity of power generation technology and heat pump technology, does not maximize the "temperature matching, cascade utilization and grade matching" of energy according to the grade of energy, thereby reducing energy loss.

[0004] At present, in the middle and deep geothermal heating, most of the heating circulation water is directly heated by plate heat exchangers and then re-injected into the re-injection well. For example, the patent with publication number CN107270371A discloses a same-layer re-injection electric heat pump type cascade utilization heating system for geothermal heating. The system mainly consists of two parts: a heat collection circulation system and a heating circulation system. The heat collection circulation system mainly consists of a water collection pump, a water collection well, a plate heat exchanger, a first valve, a second valve, an electric heat pump, a re-injection well, a third valve and a fourth valve. During operation, when the ground water temperature is higher than 40°C, the ground water directly enters the plate heat exchanger to exchange heat with the heating return water, and then enters the electric heat pump condenser for heat exchange. After the heat exchange, the low-temperature ground water enters the re-injection well for re-injection.

[0005] However, the water quality of geothermal water is relatively complex. When geothermal water directly enters the heat exchanger, it will cause serious scaling of the heat exchanger, resulting in the failure of the heat exchange effect of the heat exchanger, and even corrode the heat exchanger. At the same time, the temperature of most geothermal tail water used for reinjection is relatively high, resulting in energy waste.

[0006] Therefore, it is necessary to design a heating system that utilizes geothermal cascade in rural residences to solve the above problems. Summary of the invention

[0007] The purpose of the present invention is to provide a heating system for rural residential geothermal cascade utilization to solve the problem that the existing geothermal heating directly uses plate heat exchangers to heat, causing serious scaling of the heat exchanger, failure of the heat exchange effect, and even corrosion of the heat exchanger, as well as the relatively high temperature of the reinjected geothermal tail water.

[0008] To achieve the above object, the present invention provides the following scheme: a heating system for rural residential geothermal cascade utilization, comprising:

[0009] A water collection pump is arranged in the water collection well, and is used to collect geothermal water in the water collection well;

[0010] A sedimentation tower, connected to the water outlet of the water pump, and used for filtering and sedimenting the geothermal water collected by the water pump;

[0011] A flash heat exchange system, the inlet end of which is connected to the precipitation tower, and the flash heat exchange system is used to circulate geothermal water and exchange heat between the geothermal water and the cascade heating system;

[0012] The cascade heating system uses the heat gained through heat exchange with geothermal water to heat the indoor system;

[0013] A water heater is arranged in the cascade heating system, and the water heater uses the heat obtained by heat exchange with the geothermal water to heat the water for washing;

[0014] The outdoor water pipe is arranged in the cascade heating system. The cascade heating system uses the heat obtained by heat exchange with geothermal water to insulate the outdoor water pipe to prevent the outdoor water pipe from freezing when the temperature is lower than 0°C.

[0015] Based on the present invention, a heating system for cascade utilization of geothermal energy in rural residences, the circulating water inlet end of the water heater is connected to the cascade heating system through an inlet valve, and the circulating water outlet end of the water heater is connected to the cascade heating system through an outlet valve. A shut-off valve is arranged in the cascade heating system, and the shut-off valve is located between the inlet valve and the outlet valve. When the temperature of the water for washing in the water heater is higher than a first set value, the inlet valve and the outlet valve are closed, and the shut-off valve is opened; when the temperature of the water for washing in the water heater is lower than a second set value, the inlet valve and the outlet valve are opened, and the shut-off valve is closed, and the first set value is higher than the second set value.

[0016] In a rural residential geothermal cascade heating system based on the present invention, a heating spiral pipe is wound around the outer side of the outdoor water pipe, and the heating spiral pipe is connected to the cascade heating system. The heating spiral pipe uses the heat obtained by heat exchange with geothermal water to insulate the outdoor water pipe to prevent the outdoor water pipe from freezing when the temperature is below 0°C.

[0017] A heating system for cascade utilization of geothermal energy in rural residences based on the present invention, the flash heat exchange system comprises a primary flash evaporator and a secondary flash evaporator, the first geothermal water inlet of the primary flash evaporator is connected to the sedimentation tower through a water outlet pipe, the first water vapor outlet of the primary flash evaporator is connected to a primary condenser, the first geothermal water outlet of the primary flash evaporator is connected to a second geothermal water inlet of the secondary flash evaporator, the second water vapor outlet of the secondary flash evaporator is connected to a secondary condenser, two heated ends of the cascade heating system are respectively arranged in the primary condenser and the secondary condenser, the water outlet of the secondary flash evaporator, the water outlet of the primary condenser, and the water outlet of the secondary condenser are commonly connected to a reinjection pump, and the reinjection pump is arranged in a reinjection well.

[0018] According to the heating system of the rural residential geothermal cascade utilization of the present invention, a primary spray pump is arranged in the primary flash evaporator, the primary spray pump is located below the liquid level in the primary flash evaporator, the primary spray pump is connected to a plurality of primary spray heads through a primary spray pipe, the primary spray heads are located above the liquid level in the primary flash evaporator;

[0019] A secondary spray pump is arranged in the secondary flash evaporator, and the secondary spray pump is located below the liquid level in the secondary flash evaporator. The secondary spray pump is connected to a plurality of secondary spray heads through a secondary spray pipe, and the secondary spray heads are located above the liquid level in the secondary flash evaporator.

[0020] A heating system for cascade utilization of geothermal energy in rural residences based on the present invention, the cascade heating system includes a primary heat exchange plate, a secondary heat exchange plate, and a tertiary heat exchange plate connected in sequence, the water outlet ends of two heat receiving ends are connected to the water inlet end of the primary heat exchange plate, the return water ends of two heat receiving ends are connected to the water outlet end of the tertiary heat exchange plate, the water heater is arranged between the water outlet end of the heat receiving end and the water inlet end of the primary heat exchange plate, the outdoor water pipe is arranged between the return water end of the heat receiving end and the water outlet end of the tertiary heat exchange plate, and the primary heat exchange plate, the secondary heat exchange plate, and the tertiary heat exchange plate are used to heat the indoor system.

[0021] A heating system for cascade utilization of geothermal energy in rural residences according to the present invention, wherein the indoor system comprises an indoor radiator and floor heating, wherein the indoor radiator exchanges heat with the primary heat exchange plate, and the floor heating exchanges heat with the secondary heat exchange plate and the tertiary heat exchange plate.

[0022] A heating system for cascade utilization of geothermal energy in rural residences based on the present invention, the two heat-receiving ends include a first serpentine coil and a second serpentine coil, the water outlet end of the first serpentine coil is connected to the water inlet end of the first heat exchange plate through the first heating side outlet of the first condenser, the return water end of the first serpentine coil is connected to the water outlet end of the tertiary heat exchange plate through the first heating side inlet of the first condenser, the water outlet end of the second serpentine coil is connected to the water inlet end of the first heat exchange plate through the second heating side outlet of the second condenser, the return water end of the second serpentine coil is connected to the water outlet end of the tertiary heat exchange plate through the second heating side inlet of the second condenser, and a heat pump is arranged between the second serpentine coil and the first heat exchange plate and the tertiary heat exchange plate.

[0023] A heating system for cascade utilization of geothermal energy in rural residences based on the present invention, the heat pump includes an evaporator side inlet, an evaporator side outlet, a third heating side outlet, and a third heating side inlet, the evaporator side inlet is connected to the water outlet end of the second serpentine coil, the evaporator side outlet is connected to the return water end of the second serpentine coil, the third heating side outlet is connected to the water inlet end of the first-stage heat exchange plate, and the third heating side inlet is connected to the water outlet end of the tertiary heat exchange plate.

[0024] In a heating system for cascaded utilization of geothermal energy in rural residences according to the present invention, the top of the first-stage condenser and the top of the second-stage condenser are commonly connected with an exhaust air duct.

[0025] Compared with the prior art, the present invention has the following advantages and technical effects:

[0026] The present invention constructs a novel geothermal heating system by setting up a flash heat exchange system and a cascade heating system, and uses the heat recovered by the secondary flash evaporator as the heat source of the heat pump main unit, thereby fully recovering the heat in the geothermal water. At the same time, it is less affected by the water quality of the geothermal water, avoiding serious scaling caused by geothermal mineralized hot water and affecting the heat transfer effect. In addition, the system has a small amount of operation and maintenance and high reliability, which can achieve the purposes of energy saving, reducing maintenance workload and improving operation reliability.

[0027] The present invention can efficiently utilize all temperature ranges of medium and low temperature geothermal energy by setting up a cascade heating system, thereby improving the utilization efficiency of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work:

[0029] Figure 1 It is an overall schematic diagram of the present invention.

[0030] Among them, 1. water well; 2. water pump; 3. water pipeline; 4. sedimentation tower; 5. water outlet pipeline; 6. primary flash evaporator; 7. first geothermal water inlet; 8. first geothermal water outlet; 9. secondary flash evaporator; 10. second geothermal water inlet; 11. primary spray pump; 12. primary spray pipe; 13. primary spray head; 14. secondary spray pump; 15. secondary spray pipe; 16. secondary spray head; 17. first water vapor outlet; 18. second water vapor outlet; 19. primary condenser; 20. secondary condenser; 21. first water vapor inlet; 22. first heating side outlet; 23. first heating side outlet Side inlet; 24, second water vapor inlet; 25, second heating side outlet; 26, second heating side inlet; 27, exhaust air duct; 28, heat pump; 29, evaporator side inlet; 30, evaporator side outlet; 31, third heating side outlet; 32, third heating side inlet; 33, water heater; 34, water inlet valve; 35, water outlet valve; 36, shut-off valve; 37, primary heat exchange plate; 38, secondary heat exchange plate; 39, tertiary heat exchange plate; 40, indoor system; 41, indoor radiator; 42, floor heating; 43, heating spiral tube; 44, outdoor water pipe; 45, reinjection well; 46, reinjection pump. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Geothermal heat refers to the natural heat flow from the earth's molten rock to the outside, and is a thermal energy resource from the earth's interior. The earth's interior is a huge heat reservoir. For example, the temperature of the lava ejected by volcanoes is as high as 1200℃~1300℃, and the temperature of natural hot springs is mostly above 60℃, and some are even as high as 100℃~140℃. All this heat from the earth's interior can be converted into energy. When this heat seeps out of the surface, it becomes a geothermal resource.

[0033] Geothermal heating is called low-temperature floor radiation heating. It uses hot water not higher than 60℃ as the heat medium, which circulates in the heating pipe to heat the floor and supplies heat to the room through the ground by radiation and convection. As early as the 1970s, low-temperature floor radiation heating technology was rapidly developed in Europe, America, South Korea, Japan and other places. After time and use, it has been verified that low-temperature floor radiation heating saves energy, has mature technology, and has high thermal efficiency. It is a scientific, energy-saving and health-care heating method.

[0034] Geothermal heating is widely used in newly built houses. Generally, after one heating period, the geothermal pipes will deposit 1-1.5 mm thick scale and mud, which will reduce the indoor temperature accordingly. This is more serious in areas with poor water quality. If the pipes are not effectively cleaned for a long time, on the one hand, the water flow rate will decrease, the flow rate will slow down, and the indoor temperature will drop significantly; on the other hand, more seriously, some of them will cause pipe embolism and cannot be unblocked, resulting in permanent failure of the geothermal pipes, which is irreversible.

[0035] Judging from the current situation, to promote the healthy development of the geothermal industry, we need to start from the following four aspects:

[0036] First, we should rationally plan the development and utilization of geothermal resources, guide and regulate the development of the industry. Although geothermal energy resources are renewable resources, they require certain conditions for regeneration and cannot be infinitely regenerated. This requires relevant departments to do a good job in the planning of the geothermal industry capacity layout and industrial chain, focusing on the breakthrough of high-precision and cutting-edge technologies, and avoiding the geothermal industry chain from blindly concentrating on links with low technical content, resulting in local overcapacity and weak overall competitiveness of the entire industry.

[0037] Second, actively carry out exploration and evaluation of shallow geothermal energy resources to promote sustainable development of the industry. Geothermal energy, especially shallow geothermal energy resources, is subject to the local specific hydrogeological conditions (groundwater burial conditions, stratum structure, permeability of aquifers, groundwater quality, etc.). Only when these conditions are clearly understood can the correct choice of shallow geothermal energy utilization methods be made. Therefore, we should start with key cities in the plain area and carry out exploration and evaluation work with a scale accuracy of 1:100,000 as the main body. Based on the original hydrogeological exploration results, supplement the necessary exploration work to obtain parameters such as thermal conductivity and permeability of rock and soil. On the basis of exploration and evaluation, a shallow geothermal energy development and utilization plan should be compiled, a reasonable layout should be made, areas suitable for development and utilization should be determined, sections with different utilization methods (groundwater, buried pipes) should be delineated, and reasonable development and utilization scales and measures to prevent and control geological disasters and environmental geological problems should be proposed.

[0038] The third is to create a good environment to support the development of geothermal industry. The development and utilization of geothermal energy, especially shallow geothermal energy, requires high initial investment, but has low operation and management costs and is clean, efficient and energy-saving. It is a clean energy with good development prospects and sustainable utilization.

[0039] Fourth, we should increase the technological innovation of geothermal development and utilization and improve the technical support system. We should promote enterprises and scientific research institutions to form strategic partnerships and establish innovation alliances, so that innovation covers all important links of the entire industrial chain; we should formulate relevant technical standards and specifications to regulate the development and utilization of geothermal energy resources; we should absorb successful advanced experience in technology (such as mining and reinjection technology, power generation and heat utilization technology), introduce heat pump technology for medium and low temperature geothermal utilization, realize the cascade comprehensive utilization of geothermal resources, improve the utilization rate of geothermal energy, and then protect the ecological balance and achieve sustainable development.

[0040] Energy cascade utilization, because thermal energy cannot be completely converted into mechanical work, therefore, compared with mechanical energy and electrical energy, its quality is lower. The efficiency of heat-to-work conversion is related to the temperature, and the quality of high-temperature thermal energy is higher than that of low-temperature thermal energy. All irreversible processes proceed in the direction of reducing the quality of energy. The cascade utilization of energy can improve the energy utilization efficiency of the entire system and is an important measure for energy conservation.

[0041] The cascade utilization of energy includes two aspects: using energy according to quality and using it multiple times in stages:

[0042] (1) Using energy according to quality means that high-quality energy should not be used to do work that can be done by low-quality energy as much as possible. When high-temperature heat sources must be used for heating, the heat transfer temperature difference should be reduced as much as possible. When only high-temperature heat sources are available and only low-temperature heating is required, high-temperature heat sources should be used to generate electricity first, and then the low-temperature waste heat from the power generation device should be used for heating, such as cogeneration.

[0043] (2) Multiple utilization in stages means that the energy of high-quality energy does not have to be used up in one device or process, because in the process of using high-quality energy, the temperature of the energy gradually decreases (that is, the energy quality decreases), and each device always has a most economical and reasonable operating temperature range when consuming energy. In this way, when the high-quality energy in one device has dropped beyond the economical range, it can be transferred to another device that can use this lower-quality energy economically, so that the total energy utilization rate reaches the highest level.

[0044] Although the cascade utilization of energy is proposed for power generation and heating enterprises, it can be widely extended to various industrial processes such as refrigeration, deep cooling, chemical industry, metallurgy, etc. When necessary, heat pumps can be used to increase the temperature grade of heat sources for reuse. Different enterprises have different requirements for energy levels. The cascade utilization relationship of energy can be formed according to the energy level requirements of each energy-consuming enterprise. The high-level heat source is reduced to a low-level heat source after being used by the upper-level enterprise, and is used by enterprises with low demand. The cascade utilization of energy can effectively meet the energy needs of each unit without increasing energy consumption, greatly improving energy utilization.

[0045] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0046] Reference Figure 1 As shown, the present invention provides a heating system for geothermal cascade utilization in rural residences, comprising a water collection pump 2, which is arranged in a water collection well 1, and the water collection pump 2 is used to collect geothermal water in the water collection well 1;

[0047] The sedimentation tower 4 is connected to the water outlet of the water pump 2, and is used to filter and precipitate the geothermal water collected by the water pump 2;

[0048] A flash heat exchange system, the inlet end of which is connected to the sedimentation tower 4, and the flash heat exchange system is used to circulate the geothermal water and exchange heat between the geothermal water and the cascade heating system;

[0049] A cascade heating system, which uses the heat obtained by heat exchange with geothermal water to heat the indoor system 40;

[0050] The water heater 33 is arranged in the stepped heating system, and the water heater 33 uses the heat obtained by heat exchange with the ground water to heat the washing water;

[0051] The outdoor water pipe 44 is arranged in the cascade heating system. The cascade heating system uses the heat obtained by heat exchange with the geothermal water to insulate the outdoor water pipe 44 to prevent the outdoor water pipe 44 from freezing when the temperature is below 0°C.

[0052] As an embodiment that can be added to the present invention, the water outlet end of the water pump 2 is connected to the sedimentation tower 4 through the water collection pipe 3, the water outlet of the water collection pipe 3 is located at the bottom of the sedimentation tower 4, and the water inlet of the water outlet pipe 5 is located at the top of the sedimentation tower 4. This arrangement allows the geothermal water to enter the sedimentation tower 4 and gradually fill the entire sedimentation tower 4 from bottom to top. After the geothermal water fills the entire sedimentation tower 4, it enters the flash heat exchange system by overflow, and the impurities contained in the geothermal water are deposited at the bottom of the sedimentation tower 4, thereby realizing the separation of water and impurities and preventing impurities from entering the flash heat exchange system and causing system operation failures.

[0053] Furthermore, the circulating water inlet end of the water heater 33 is connected to the cascade heating system through the water inlet valve 34, and the circulating water outlet end of the water heater 33 is connected to the cascade heating system through the water outlet valve 35. A shut-off valve 36 is provided in the cascade heating system, and the shut-off valve 36 is located between the water inlet valve 34 and the water outlet valve 35. When the temperature of the washing water in the water heater 33 is higher than the first set value, the water inlet valve 34 and the water outlet valve 35 are closed, and the shut-off valve 36 is opened; when the temperature of the washing water in the water heater 33 is lower than the second set value, the water inlet valve 34 and the water outlet valve 35 are opened, and the shut-off valve 36 is closed. The first set value is higher than the second set value.

[0054] Furthermore, a heating spiral tube 43 is wound around the outside of the outdoor water pipe 44, and the heating spiral tube 43 is connected to the stepped heating system. The heating spiral tube 43 uses the heat obtained by heat exchange with geothermal water to insulate the outdoor water pipe 44 to prevent the outdoor water pipe 44 from freezing when the temperature is below 0°C.

[0055] Furthermore, the flash heat exchange system includes a primary flash evaporator 6 and a secondary flash evaporator 9. The first geothermal water inlet 7 of the primary flash evaporator 6 is connected to the sedimentation tower 4 through the outlet pipe 5. The first water vapor outlet 17 of the primary flash evaporator 6 is connected to the primary condenser 19. The first geothermal water outlet 8 of the primary flash evaporator 6 is connected to the second geothermal water inlet 10 of the secondary flash evaporator 9. The second water vapor outlet 18 of the secondary flash evaporator 9 is connected to the secondary condenser 20. The two heated ends of the cascade heating system are respectively arranged in the primary condenser 19 and the secondary condenser 20. The water outlet of the secondary flash evaporator 9, the water outlet of the primary condenser 19, and the water outlet of the secondary condenser 20 are commonly connected to a recharge pump 46, and the recharge pump 46 is arranged in a recharge well 45.

[0056] The primary flash evaporator 6 is connected to a primary vacuum pump, and the secondary flash evaporator 9 is connected to a secondary vacuum pump.

[0057] The first water vapor outlet 17 is communicated with the primary condenser 19 through the first water vapor inlet 21 , and the second water vapor outlet 18 is communicated with the secondary condenser 20 through the second water vapor inlet 24 .

[0058] Furthermore, a primary spray pump 11 is provided in the primary flash evaporator 6, the primary spray pump 11 is located below the liquid level in the primary flash evaporator 6, the primary spray pump 11 is connected to a plurality of primary spray heads 13 through a primary spray pipe 12, and the primary spray heads 13 are located above the liquid level in the primary flash evaporator 6;

[0059] A secondary spray pump 14 is provided in the secondary flash evaporator 9 . The secondary spray pump 14 is located below the liquid level in the secondary flash evaporator 9 . The secondary spray pump 14 is connected to a plurality of secondary spray heads 16 through a secondary spray pipe 15 . The secondary spray heads 16 are located above the liquid level in the secondary flash evaporator 9 .

[0060] The geothermal water enters the primary flash evaporator 6 through the water pump 2, the water pipeline 3, and the water outlet pipeline 5. The primary vacuum pump draws the primary flash evaporator 6 into a vacuum state, and the geothermal water entering the primary flash evaporator 6 is rapidly vaporized into steam, and the steam enters the primary condenser 19 through the first water vapor outlet 17 and the first water vapor inlet 21 in turn. In the primary condenser 19, the heating circulation medium flows in the water pipe, and the steam is outside the water pipe, so the steam and the heating circulation medium exchange heat indirectly. The heat released by the steam is absorbed by the heating circulation medium, and the temperature of the heating circulation medium rises and is sent to the cascade heating system through the heating water supply pipeline. The geothermal steam after releasing the heat becomes condensed water and is discharged from the water outlet of the primary condenser 19. A part of condensed water is also produced in the primary flash evaporator 6, and the condensed water flows out through the first geothermal water outlet 8 and enters the secondary flash evaporator 9. The secondary vacuum pump draws the secondary flash evaporator 9 into a vacuum state, and the geothermal water entering the secondary flash evaporator 9 is rapidly vaporized into steam. The steam in the secondary flash evaporator 9 enters the secondary condenser 20 through the second water vapor outlet 18 and the second water vapor inlet 24 in turn. The water vapor releases heat and condenses in the secondary condenser 20, and the released heat is transferred to the evaporator of the heat pump 28. The heating return water enters the condenser of the heat pump 28 through the heating return water pipeline, absorbs the heat released by the evaporator of the heat pump 28, and after the heating water temperature rises, it is sent to the cascade heating system through the heating water supply pipeline. The condensed water of the secondary condenser 20 is discharged into the recharging pump 46 through the water outlet of the secondary condenser 20. Part of the condensed water in the secondary flash evaporator 9 is discharged into the recharging pump 46 through the second geothermal water outlet.

[0061] Furthermore, the cascade heating system includes a primary heat exchange plate 37, a secondary heat exchange plate 38, and a tertiary heat exchange plate 39 which are connected in sequence, the water outlet ends of the two heat receiving ends are connected to the water inlet end of the primary heat exchange plate 37, the return water ends of the two heat receiving ends are connected to the water outlet end of the tertiary heat exchange plate 39, the water heater 33 is arranged between the water outlet end of the heat receiving end and the water inlet end of the primary heat exchange plate 37, the outdoor water pipe 44 is arranged between the return water end of the heat receiving end and the water outlet end of the tertiary heat exchange plate 39, and the primary heat exchange plate 37, the secondary heat exchange plate 38, and the tertiary heat exchange plate 39 are used to heat the indoor system 40.

[0062] Furthermore, the indoor system 40 includes an indoor radiator 41 and a floor heater 42 . The indoor radiator 41 performs heat exchange with the primary heat exchange plate 37 , and the floor heater 42 performs heat exchange with the secondary heat exchange plate 38 and the tertiary heat exchange plate 39 .

[0063] Furthermore, the two heat-receiving ends include a first serpentine coil and a second serpentine coil, the water outlet end of the first serpentine coil is connected to the water inlet end of the first heat exchange plate 37 through the first heating side outlet 22 of the first condenser 19, the return water end of the first serpentine coil is connected to the water outlet end of the tertiary heat exchange plate 39 through the first heating side inlet 23 of the first condenser 19, the water outlet end of the second serpentine coil is connected to the water inlet end of the first heat exchange plate 37 through the second heating side outlet 25 of the secondary condenser 20, the return water end of the second serpentine coil is connected to the water outlet end of the tertiary heat exchange plate 39 through the second heating side inlet 26 of the secondary condenser 20, and a heat pump 28 is arranged between the second serpentine coil and the first and third heat exchange plates 37 and 39.

[0064] Furthermore, the heat pump 28 includes an evaporator side inlet 29, an evaporator side outlet 30, a third heating side outlet 31, and a third heating side inlet 32. The evaporator side inlet 29 is connected to the water outlet end of the second serpentine coil, the evaporator side outlet 30 is connected to the return water end of the second serpentine coil, the third heating side outlet 31 is connected to the water inlet end of the first-stage heat exchange plate 37, and the third heating side inlet 32 ​​is connected to the water outlet end of the tertiary heat exchange plate 39.

[0065] Furthermore, the top of the primary condenser 19 and the top of the secondary condenser 20 are commonly connected to an exhaust air duct 27 .

[0066] The primary heat exchange plate 37 reduces the temperature of geothermal water at 75°C to 60°C, and the user side of the primary heat exchange plate 37 is connected to the indoor radiator 41 in the building, supplying circulating hot water at 60°C to 55°C for heating. The secondary heat exchange plate 38 reduces the temperature of geothermal water at 60°C to 45°C, and the user side of the secondary heat exchange plate 38 is connected to the floor heating 42 in the building. Since the radiation terminal has a lower demand for water supply temperature, circulating hot water at 45°C to 35°C can be supplied for heating. The tertiary heat exchange plate 39 reduces the temperature of geothermal water at 45°C to 35°C, and the tertiary heat exchange plate 39 supplies it to the floor heating 42 for indoor heating.

[0067] Before the cascade heating, the geothermal water first heats the washing water in the water heater 33. During heating, the water inlet valve 34 and the water outlet valve 35 are opened and the shut-off valve 36 is closed. The geothermal water enters the water heater 33 through the water inlet valve 34 to heat the washing water and then flows into the cascade heating system through the water outlet valve 35 for heating. After the temperature of the washing water is heated to a first set value, the water inlet valve 34 and the water outlet valve 35 are closed and the shut-off valve 36 is opened. The geothermal water directly enters the cascade heating system for heating without passing through the water heater 33. When the temperature of the washing water in the water heater 33 drops below a second set value, the water inlet valve 34 and the water outlet valve 35 are opened again and the shut-off valve 36 is closed to use the geothermal water to heat the washing water.

[0068] After the step heating, the geothermal water is discharged from the outlet of the three-stage heat exchange plate 39 and enters the heating spiral tube 43, and the waste heat is used to insulate the outdoor water pipe 44, so that the water in the outdoor water pipe 44 is kept above 0°C without freezing.

[0069] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0070] The embodiments described above are only descriptions of the preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the protection scope of the present invention.

Claims

1. A heating system for cascade utilization of geothermal energy in rural residences, characterized in that: include A water collection pump (2) is arranged in the water collection well (1), and the water collection pump (2) is used to collect geothermal water in the water collection well (1); A sedimentation tower (4) is connected to the water outlet of the water collection pump (2), and the sedimentation tower (4) is used to filter and precipitate the geothermal water collected by the water collection pump (2); A flash heat exchange system, the inlet end of which is connected to the precipitation tower (4), the flash heat exchange system is used to circulate geothermal water and enable the geothermal water to exchange heat with the cascade heating system; A cascade heating system, using heat obtained by heat exchange with geothermal water to heat the indoor system (40); A water heater (33) is arranged in the stepped heating system, and the water heater (33) uses the heat obtained by heat exchange with geothermal water to heat the water for washing; An outdoor water pipe (44) is arranged in the cascade heating system. The cascade heating system uses the heat obtained by heat exchange with geothermal water to insulate the outdoor water pipe (44) to prevent the outdoor water pipe (44) from freezing when the temperature is lower than 0°C.

2. A heating system for cascade utilization of geothermal energy in rural residences according to claim 1, characterized in that: The circulating water inlet end of the water heater (33) is communicated with the cascade heating system through the water inlet valve (34), and the circulating water outlet end of the water heater (33) is communicated with the cascade heating system through the water outlet valve (35). A cut-off valve (36) is provided in the cascade heating system. The cut-off valve (36) is located between the water inlet valve (34) and the water outlet valve (35). When the temperature of the washing water in the water heater (33) is higher than a first set value, the water inlet valve (34) and the water outlet valve (35) are closed, and the cut-off valve (36) is opened; when the temperature of the washing water in the water heater (33) is lower than a second set value, the water inlet valve (34) and the water outlet valve (35) are opened, and the cut-off valve (36) is closed. The first set value is higher than the second set value.

3. A heating system for cascade utilization of geothermal energy in rural residences according to claim 1, characterized in that: A heating spiral tube (43) is wound around the outside of the outdoor water pipe (44), and the heating spiral tube (43) is connected to the stepped heating system. The heating spiral tube (43) uses the heat obtained by heat exchange with geothermal water to keep the outdoor water pipe (44) warm, thereby preventing the outdoor water pipe (44) from freezing when the temperature is below 0°C.

4. A heating system for cascade utilization of geothermal energy in rural residences according to claim 1, characterized in that: The flash heat exchange system comprises a primary flash evaporator (6) and a secondary flash evaporator (9); a first geothermal water inlet (7) of the primary flash evaporator (6) is connected to the precipitation tower (4) through a water outlet pipe (5); a first water vapor outlet (17) of the primary flash evaporator (6) is connected to a primary condenser (19); a first geothermal water outlet (8) of the primary flash evaporator (6) is connected to a second geothermal water inlet (10) of the secondary flash evaporator (9); a second water vapor outlet (18) of the secondary flash evaporator (9) is connected to a secondary condenser (20); two heat receiving ends of the cascade heating system are respectively arranged in the primary condenser (19) and in the secondary condenser (20); a water outlet of the secondary flash evaporator (9), a water outlet of the primary condenser (19), and a water outlet of the secondary condenser (20) are commonly connected to a reinjection pump (46); and the reinjection pump (46) is arranged in a reinjection well (45).

5. A heating system for cascade utilization of geothermal energy in rural residences according to claim 4, characterized in that: A primary spray pump (11) is arranged in the primary flash evaporator (6), the primary spray pump (11) is located below the liquid level in the primary flash evaporator (6), the primary spray pump (11) is connected to a plurality of primary spray heads (13) through a primary spray pipe (12), the primary spray heads (13) are located above the liquid level in the primary flash evaporator (6); A secondary spray pump (14) is arranged in the secondary flash evaporator (9), and the secondary spray pump (14) is located below the liquid level in the secondary flash evaporator (9). The secondary spray pump (14) is connected to a plurality of secondary spray heads (16) through a secondary spray pipe (15), and the secondary spray heads (16) are located above the liquid level in the secondary flash evaporator (9).

6. A heating system for cascade utilization of geothermal energy in rural residences according to claim 4, characterized in that: The cascade heating system comprises a primary heat exchange plate (37), a secondary heat exchange plate (38), and a tertiary heat exchange plate (39) which are connected in sequence; the water outlets of two heat receiving ends are connected to the water inlet of the primary heat exchange plate (37); the water return ends of the two heat receiving ends are connected to the water outlet of the tertiary heat exchange plate (39); the water heater (33) is arranged between the water outlet of the heat receiving end and the water inlet of the primary heat exchange plate (37); the outdoor water pipe (44) is arranged between the water return end of the heat receiving end and the water outlet of the tertiary heat exchange plate (39); the primary heat exchange plate (37), the secondary heat exchange plate (38), and the tertiary heat exchange plate (39) are used to supply heat to the indoor system (40).

7. A heating system for cascade utilization of geothermal energy in rural residences according to claim 6, characterized in that: The indoor system (40) comprises an indoor radiator (41) and a floor heater (42); the indoor radiator (41) performs heat exchange with the primary heat exchange plate (37); and the floor heater (42) performs heat exchange with the secondary heat exchange plate (38) and the tertiary heat exchange plate (39).

8. A heating system for cascade utilization of geothermal energy in rural residences according to claim 6, characterized in that: The two heat receiving ends include a first serpentine coil and a second serpentine coil. The water outlet of the first serpentine coil is connected to the water inlet of the first heat exchange plate (37) through the first heating side outlet (22) of the first condenser (19). The return water end of the first serpentine coil is connected to the water outlet of the tertiary heat exchange plate (39) through the first heating side inlet (23) of the first condenser (19). The water outlet of the second serpentine coil is connected to the water inlet of the first heat exchange plate (37) through the second heating side outlet (25) of the second condenser (20). The return water end of the second serpentine coil is connected to the water outlet of the tertiary heat exchange plate (39) through the second heating side inlet (26) of the second condenser (20). A heat pump (28) is arranged between the second serpentine coil and the first heat exchange plate (37) and the tertiary heat exchange plate (39).

9. A heating system for cascade utilization of geothermal energy in rural residences according to claim 8, characterized in that: The heat pump (28) comprises an evaporator side inlet (29), an evaporator side outlet (30), a third heating side outlet (31), and a third heating side inlet (32); the evaporator side inlet (29) is connected to the water outlet end of the second serpentine coil; the evaporator side outlet (30) is connected to the return water end of the second serpentine coil; the third heating side outlet (31) is connected to the water inlet end of the first-stage heat exchange plate (37); and the third heating side inlet (32) is connected to the water outlet end of the third-stage heat exchange plate (39).

10. A heating system for cascade utilization of geothermal energy in rural residences according to claim 4, characterized in that: The top end of the primary condenser (19) and the top end of the secondary condenser (20) are commonly connected to an air exhaust pipe (27).

Images