Geothermal well heating system

Abstract

The utility model discloses a geothermal well heating system, which belongs to the technical field of geothermal systems and comprises a primary heat exchanger, a secondary heat exchanger and a heat pump unit, one end of the primary heat exchanger is connected with a geothermal well through a first electric valve, and the other end of the primary heat exchanger is connected with a user side; the heat flow end of the second-stage heat exchanger is connected with the geothermal well through a second electric valve, the cold flow end of the second-stage heat exchanger is connected with an evaporator of the heat pump unit, and a condenser of the heat pump unit is connected with the user side. Different heating states and stages of the geothermal well can be adapted, the utilization rate of geothermal energy is increased, energy is saved, and excessive heating of the geothermal well is avoided; and in one heating period, a plurality of heating components are used in turn, so that the service life of each component is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of geothermal systems, in particular to a geothermal well heating system. Background Art

[0002] The medium-deep geothermal heat in geothermal wells is an environmentally friendly, clean and renewable energy source, and is often used in geothermal power generation, industrial heating, winter heating and other fields. Medium-deep geothermal heat is safe, stable, and not affected by seasonal and diurnal changes. It is often used in heating systems in cold northern areas with rich geothermal resources. Geothermal wells are usually closed geothermal wells for closed heat extraction.

[0003] The middle and deep layers usually adopt the "heat but not water" mining mode. In areas with relatively rich geothermal resources, the temperature of deep strata is relatively high, which may reach over 100°C. After balanced circulation, the outlet water temperature of geothermal wells can reach over 80°C. At this time, if heating is provided by heat pump, the high-temperature geothermal water needs to be lowered first to reach a temperature that meets the requirements of the heat source of the heat pump (generally the inlet water temperature is below 30°C) and then the heat source is transported out. This method greatly wastes the heat resources of the middle and deep layers and causes huge energy waste.

[0004] Therefore, it is necessary to design a cascade heating system that utilizes geothermal wells to utilize geothermal energy for heating in an efficient and energy-saving manner to solve the problem of heat resource waste in medium and deep geothermal areas. Utility Model Content

[0005] In view of the above technical problems existing in the prior art, the utility model provides a geothermal well heating system to avoid the waste of geothermal heat resources.

[0006] The utility model discloses a geothermal well heating system, comprising a primary heat exchanger, a secondary heat exchanger and a heat pump unit, wherein one end of the primary heat exchanger is connected to the geothermal well through a first electric valve, and the other end is connected to a user side; the hot flow end of the secondary heat exchanger is connected to the geothermal well through a second electric valve, and the cold flow end is connected to the evaporator of the heat pump unit, and the condenser of the heat pump unit is connected to the user side.

[0007] Preferably, the input port of the hot flow end of the secondary heat exchanger is provided with a three-way regulating valve, and the three ports of the three-way regulating valve are respectively connected to the second electric valve, the secondary heat exchanger and the return end of the geothermal well;

[0008] The output port of the hot flow end of the secondary heat exchanger is connected to the return flow end of the geothermal well.

[0009] Preferably, the output end of the heat pump unit is provided with a fourth electric terminal; the cold flow end of the primary heat exchanger is provided with a fifth electric valve.

[0010] Preferably, the utility model also includes any of the following circulating pumps or their combination:

[0011] Primary side circulation pump, secondary side circulation pump and user side circulation pump;

[0012] The primary side circulation pump is installed at the return end of the geothermal well;

[0013] The secondary side circulation pump is installed at the cold flow end of the secondary heat exchanger;

[0014] The user-side circulation pump is installed at the input end or the output end of the user side.

[0015] Preferably, the utility model further comprises a water replenishment component,

[0016] The water replenishment assembly includes a user-side constant-pressure water replenisher, a secondary-side constant-pressure water replenisher and a primary-side constant-pressure water replenisher.

[0017] The output end of the user-side constant-pressure water make-up device is connected to the user-side circulation pump;

[0018] The output end of the secondary side constant pressure water make-up device is connected to the secondary side circulation pump;

[0019] The output end of the primary-side constant-pressure water make-up device is connected to the primary-side circulation pump.

[0020] Preferably, a pressure water tank is provided at the input end of the secondary side circulation pump.

[0021] Preferably, the water replenishment assembly also includes a softening water tank and a softener.

[0022] The water supply end of the softener is connected to the softened water tank;

[0023] The softened water tank is connected to the user-side constant-pressure water make-up device, the secondary-side constant-pressure water make-up device and the primary-side constant-pressure water make-up device.

[0024] Preferably, the circulation pump comprises two water pumps connected in parallel.

[0025] The utility model also provides a heating method of the heating system, comprising the following steps:

[0026] Determine whether the water supply temperature of the geothermal well meets any of the following conditions:

[0027] First condition: the water supply temperature is greater than or equal to the first threshold;

[0028] Second condition: the water supply temperature is between the first threshold and the second threshold;

[0029] The third condition: the water supply temperature is less than or equal to the second threshold;

[0030] If the first condition is met, the first electric valve is opened and the second electric valve is closed, and heating is provided to the user side through the primary heat exchanger;

[0031] If the second condition is met, the first electric valve and the second electric valve are opened, and the heat pump unit is turned on, and the heat pump unit is supplied with heat through the secondary heat exchanger, and the user side is jointly heated through the primary heat exchanger and the heat pump unit;

[0032] If the third condition is met, the first electric valve is closed and the second electric valve is opened, and heat is supplied to the heat pump unit through the secondary heat exchanger, and heating is supplied to the user side through the heat pump unit.

[0033] Preferably, if the second or third condition is met,

[0034] determining whether the water supply temperature is less than a third threshold;

[0035] If it is less than the third threshold, the flow rate of the primary-side circulation pump is reduced, and / or the opening of the three-way regulating valve is increased.

[0036] Compared with the prior art, the beneficial effects of the utility model are: it can adapt to different heating states and stages of geothermal wells, improve the utilization rate of geothermal energy, save energy, and avoid excessive heating of geothermal wells; within one heating cycle, multiple heating components are used in turn to increase the service life of each component. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a logic block diagram of the geothermal well heating system of the utility model;

[0038] Figure 2 It is a schematic diagram of the geothermal well heating system;

[0039] Figure 3 It is a flow chart of the heating method of the utility model.

[0040] Markings in the figure: 1 geothermal well, 11 primary side circulation pump, 2 primary heat exchanger, 21 first electric valve, 25 fifth electric valve, 3 second heat exchanger, 32 second electric valve, 33 three-way regulating valve, 36 pressure water tank, 37 secondary side circulation pump, 5 heat pump unit, 51 fourth electric valve, 6 user side, 68 user side circulation pump, 7 water make-up component, 72 softening water tank, 73 softener, 74 user side constant pressure water make-up device, 75 secondary side constant pressure water make-up device, 76 primary side constant pressure water make-up device. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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.

[0042] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0043] A geothermal well heating system, such as Figure 1 and Figure 2 As shown, it includes a primary heat exchanger 2, a secondary heat exchanger 3 and a heat pump unit 5, one end of the primary heat exchanger 2 is connected to the geothermal well 1 through a first electric valve 21, and the other end is connected to the user side 6; the hot flow end of the secondary heat exchanger 3 is connected to the geothermal well 1 through a second electric valve 32, and the cold flow end is connected to the evaporator of the heat pump unit 5, and the condenser of the heat pump unit 5 is connected to the user side.

[0044] The heating mode can be adjusted according to the water supply temperature or heating stage of the geothermal well: in the early stage of heating, the geothermal heat is sufficient, and the user side 6 is heated through the primary heat exchanger 2; in the middle stage of heating, the geothermal heat is insufficient to fully supply the user side, and the heat pump unit 5 is heated through the secondary heat exchanger 3, and the user side is heated jointly through the primary heat exchanger 2 and the heat pump unit 5; in the late stage of heating, the heat supply of the geothermal well drops seriously, the heating capacity of the primary heat exchanger is insufficient, and even interferes with the heating of the heat pump unit, and the heat pump unit 5 is heated through the secondary heat exchanger 3, and the user side is heated through the heat pump unit 5. It can adapt to different heating states and stages of geothermal wells, improve the utilization rate of geothermal energy, save energy, and avoid excessive heating of geothermal wells; in one heating cycle, multiple heating components are used in turn to increase the service life of each component.

[0045] Among them, the input port of the hot flow end of the secondary heat exchanger 3 is provided with a three-way regulating valve 33, and the three ports of the three-way regulating valve 33 are respectively connected to the second electric valve 32, the secondary heat exchanger 3 and the return end of the geothermal well; the output port of the hot flow end of the secondary heat exchanger 3 is connected to the return end of the geothermal well. The output end of the heat pump unit 5 is provided with a fourth electric end 51; the cold flow end of the primary heat exchanger 2 is provided with a fifth electric valve. The three-way regulating valve 33 is used to adjust the water supply and heat supply of the secondary heat exchanger 3 to avoid excessive heat extraction.

[0046] Figure 2A specific design is shown, including circulating pumps: a primary side circulating pump 11, a secondary side circulating pump 37 and a user side circulating pump 68; the primary side circulating pump 11 is installed at the return end of the geothermal well 1; the secondary side circulating pump 37 is installed at the cold flow end of the secondary heat exchanger 3; the user side circulating pump 68 is installed at the input end or output end of the user side. They are used to provide circulating power for the primary side, the secondary side and the user side respectively. In the case of insufficient heating of the geothermal well, the flow rate of the primary side circulating pump 11 can be adjusted; and the water supply of the geothermal well can be adjusted in combination with the three-way regulating valve 33.

[0047] More specifically, the circulation pump includes two water pumps connected in parallel.

[0048] Figure 2 A water replenishment assembly 7 is also shown, and the water replenishment assembly 7 includes a user-side constant pressure water replenisher 74, a secondary-side constant pressure water replenisher 75, and a primary-side constant pressure water replenisher 76. The output end of the user-side constant pressure water replenisher 74 is connected to the user-side circulation pump 68, specifically to the input end of the user-side circulation pump 68; the output end of the secondary-side constant pressure water replenisher 75 is connected to the secondary-side circulation pump 37; the output end of the primary-side constant pressure water replenisher 76 is connected to the primary-side circulation pump 11, preferably to the input end of the primary-side circulation pump. A pressure water tank 36 is also provided at the input end of the secondary-side circulation pump 37.

[0049] The water replenishment assembly 7 also includes a softened water tank 72 and a softener 73. The water supply end of the softener 73 is connected to the softened water tank 72; the softened water tank 72 is connected to the user-side constant pressure water replenisher 74, the secondary-side constant pressure water replenisher 75 and the primary-side constant pressure water replenisher 76. To maintain normal operating pressure. The softened water tank 72 can be a glass fiber reinforced plastic softened water tank, and the water softener is a fully automatic water softener to prevent scaling in the system and protect the equipment.

[0050] The heating system of the present invention has a small number of valve switches, a clear and concise water flow loop, and is equipped with a two-stage plate heat exchanger, which can fully utilize the heat of high-temperature and low-temperature working conditions of geothermal well circulating water, thereby reducing the power consumption of the heat pump unit while increasing the temperature and saving energy.

[0051] The present invention also provides a heating method of the above heating system, such as Figure 3 , including the following steps:

[0052] Step 101: Obtaining the water supply temperature of the geothermal well;

[0053] Step 102: Determine whether the water supply temperature of the geothermal well meets any of the following conditions:

[0054] First condition: the water supply temperature is greater than or equal to the first threshold;

[0055] Second condition: the water supply temperature is between the first threshold and the second threshold;

[0056] Third condition: the water supply temperature is less than or equal to the second threshold.

[0057] If the first condition is met, step 103 is executed: the first electric valve 21 is opened, and the second electric valve 32 is closed, so as to provide heating for the user side 6 through the primary heat exchanger 2 .

[0058] If the second condition is met, execute step 104: open the first electric valve 21 and the second electric valve 32, and turn on the heat pump unit 5, supply heat to the heat pump unit 5 through the secondary heat exchanger 3, and provide joint heating to the user side through the primary heat exchanger 2 and the heat pump unit 5.

[0059] If the third condition is met, step 105 is executed: the first electric valve 21 is closed, and the second electric valve 32 is opened, and the heat pump unit 5 is heated through the secondary heat exchanger 3, and the heat pump unit 5 is used to heat the user side.

[0060] When the second condition or the third condition is satisfied, it is determined whether the supply water temperature is lower than a third threshold value.

[0061] If it is less than the third threshold, reduce the flow rate of the primary side circulation pump 11, and / or increase the opening of the three-way regulating valve 33. Protect the geothermal well to avoid excessive heat extraction. The third threshold can be obtained based on testing or experience. It should be noted that the third threshold when the second condition is met and the third condition is met has different water supply temperature values.

[0062] However, the above conditions may also take into account the external ambient temperature of the heating area.

[0063] The system design of the present invention is environmentally friendly, efficient and energy-saving, and can solve the problem of heat resource waste in deep and medium-layer geothermal energy. The circulating geothermal water is heated by a two-stage plate heat exchanger and a heat pump unit for heating the circulating water on the user side. There are three cascade heating operation modes for utilizing geothermal wells.

[0064] The first type is that in the initial stage of heating, the closed geothermal well exchanges heat through the primary heat exchanger (plate heat exchanger), and the geothermal well primary side circulation pump and the user side circulation pump are driven separately to heat the terminal buildings on the user side. The deep stratum temperature may reach above 100°C, and the geothermal well outlet water temperature can reach above 80°C after balanced circulation. The second electric valve 32 and the fourth electric valve 51 can be closed, and the first electric valve 21 and the fifth electric valve 25 can be opened.

[0065] The second type is that the heat load demand at the terminal increases in the middle of heating, the load of the closed geothermal well decreases, and the direct heat exchange of the geothermal well cannot meet the heating demand at the terminal. At this time, the secondary heat exchanger 3 is opened, and the primary heat exchanger 2 is kept to directly heat the terminal after heat exchange, while the secondary plate heat exchanger provides a heat source for the heat pump unit. After the heat pump unit heats, it and the plate heat exchanger are used to heat the terminal together, and the heat pump unit assists in heating. The second electric valve 32, the fifth electric valve 25 and the fourth electric valve 51 can be opened, and the opening of the three-way regulating valve 33 can be adjusted according to the temperature of the geothermal circulating water.

[0066] The third type is that at the end of the heating period, the temperature of the closed geothermal well decreases and it is impossible to directly heat the building through the primary plate heat exchanger. The power of the heat pump unit gradually increases and becomes the main heating method for the terminal building. At this time, the circulating water of the geothermal well is directly exchanged by the secondary plate heat exchanger to provide a heat source for the heat pump unit, which then heats up the building and closes the primary heat exchanger 2. The first electric valve 21 and the fifth electric valve 25 can be closed, and the second electric valve 32 and the fourth electric valve 51 can be opened.

[0067] The heating method of the present invention improves the utilization efficiency of geothermal wells, saves energy and prolongs the service life of the heat pump unit.

[0068] The heating system of the present invention has the following beneficial effects: actively responding to the national call, vigorously developing green energy, and complying with the development concept of low-carbon energy conservation. Reduce operating costs, the heat pump unit is not fully turned on during the entire winter operation cycle, which can effectively reduce the consumption of electricity. Easy to operate and highly flexible, it is only necessary to open and close individual valves by observing the circulating water temperature on the primary side of the geothermal well. Wide range of applications, this system is suitable for most northern regions, and the power and number of heat pump units are determined according to the system load. The loss rate of equipment use is reduced, the use time of a single heating season of a high-temperature heat pump unit is reduced, the service life of the heat pump unit is increased, and a softening water tank and a fully automatic water softener are provided to prevent equipment scaling. It protects geothermal wells and prevents excessive heat collection from geothermal wells; it does not affect the operation effect of the geothermal wells in the second year.

[0069] The heat pump unit of the present invention can adopt the existing heat pump unit on the market, wherein the condensing agent in the evaporator evaporates to absorb heat, and the condensing agent in the condenser condenses to release heat. The primary heat exchanger and the secondary heat exchanger can adopt plate heat exchangers, the input port of the hot flow end of the plate heat exchanger is connected to the output end of the geothermal well, and the output port is connected to the return end of the geothermal well, and releases heat; the cold flow (such as water) at the cold flow end of the plate heat exchanger flows through the plate heat exchanger to absorb heat and realize heat exchange.

[0070] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A geothermal well heating system, characterized in that: It comprises a primary heat exchanger (2), a secondary heat exchanger (3) and a heat pump unit (5), One end of the primary heat exchanger (2) is connected to the geothermal well (1) via a first electric valve (21), and the other end is connected to the user side (6); The hot flow end of the secondary heat exchanger (3) is connected to the geothermal well (1) via a second electric valve (32), and the cold flow end is connected to the evaporator of the heat pump unit (5), and the condenser of the heat pump unit (5) is connected to the user side.

2. The geothermal well heating system according to claim 1, characterized in that: The input port of the hot flow end of the secondary heat exchanger (3) is provided with a three-way regulating valve (33), and the three ports of the three-way regulating valve (33) are respectively connected to the second electric valve (32), the secondary heat exchanger (3) and the return end of the geothermal well; The output port of the hot flow end of the secondary heat exchanger (3) is connected to the return flow end of the geothermal well.

3. The geothermal well heating system according to claim 1, characterized in that: The output end of the heat pump unit (5) is provided with a fourth electric end (51); A fifth electric valve (25) is provided at the cold flow end of the primary heat exchanger (2).

4. The geothermal well heating system according to any one of claims 1 to 3, characterized in that: Also includes any one or combination of the following circulation pumps: A primary side circulation pump (11), a secondary side circulation pump (37) and a user side circulation pump (68); The primary side circulation pump (11) is installed at the return end of the geothermal well (1); The secondary side circulation pump (37) is installed at the cold flow end of the secondary heat exchanger (3); The user-side circulation pump (68) is installed at the input end or the output end of the user side.

5. The geothermal well heating system according to claim 4, characterized in that: It also includes a water replenishment component (7), The water replenishment assembly (7) comprises a user-side constant-pressure water replenisher (74), a secondary-side constant-pressure water replenisher (75) and a primary-side constant-pressure water replenisher (76). The output end of the user-side constant-pressure water replenisher (74) is connected to the user-side circulation pump (68); The output end of the secondary side constant pressure water replenisher (75) is connected to the secondary side circulation pump (37); The output end of the primary-side constant-pressure water make-up device (76) is connected to the primary-side circulation pump (11).

6. The geothermal well heating system according to claim 5, characterized in that: A pressure water tank (36) is provided at the input end of the secondary side circulation pump (37).

7. The geothermal well heating system according to claim 5, characterized in that: The water replenishment assembly (7) further comprises a softening water tank (72) and a softener (73). The water supply end of the softener (73) is connected to the softened water tank (72); The softened water tank (72) is connected to the user-side constant-pressure water make-up device (74), the secondary-side constant-pressure water make-up device (75) and the primary-side constant-pressure water make-up device (76).

8. The geothermal well heating system according to claim 4, characterized in that: The circulation pump consists of two water pumps connected in parallel.

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