Heating system based on waste heat recovery of generator set

Abstract

The invention relates to the technical field of heating, in particular to a heating system based on waste heat recovery of a generator set, which comprises a waste heat collection unit comprising a plate heat exchanger and a cooling tower which are connected in parallel on a condenser circulating pipeline of the generator set, and a switching valve group is arranged between the plate heat exchanger and the cooling tower; the underground energy storage unit comprises a first mining and recharging well and a second mining and recharging well which are connected with the plate heat exchanger through a heat exchange pipeline, and the bottoms of the first mining and recharging well and the second mining and recharging well are thermally coupled through a high-heat-conduction filling layer; the heat pump unit comprises a lithium bromide absorption heat pump, and a low-temperature heat source inlet of the lithium bromide absorption heat pump is connected with an outlet of the plate heat exchanger and a water pumping pipeline of the first mining and recharging well in parallel. Compared with the prior art, the system has the advantages that the underground energy storage unit and the switching valve group are arranged to operate cooperatively and work cooperatively, heat supply safety is guaranteed, meanwhile, overground and underground integrated waste heat regulation, storage, release and control are achieved, and the stability, the regulation capacity and the energy comprehensive utilization efficiency of the system are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of heating technology, and in particular to a heating system based on waste heat recovery of a generator set. BACKGROUND

[0002] With the acceleration of urbanization and the continuous improvement of residents' living standards, winter heating has become an important part of urban public services, which not only relates to the comfort of residents' life, but also affects the energy structure and environmental quality of urban operation. At present, most cities still mainly rely on cogeneration systems for centralized heating. This kind of system uses the medium-high temperature steam generated by the generator set as the heat source, which provides power while meeting the heating demand, and has certain advantages in energy utilization efficiency.

[0003] In the prior art, a large amount of circulating water waste heat generated by the condenser of the generator set is usually directly discharged through the cooling tower, lacking effective heat collection and recovery mechanism, which not only causes a large waste of low-grade waste heat resources, but also increases the consumption of cooling water resources and the operating burden of equipment. With the acceleration of urbanization and the decline of the thermal insulation performance of old buildings, the heating load of residents continues to rise. However, the traditional cogeneration system is limited by the operation period, heating radius and equipment capacity, and it is difficult to flexibly respond to peak heat load. Therefore, problems such as insufficient heating coverage and low end temperature often occur, and the peak shaving capacity is seriously insufficient. In addition, this kind of system usually relies on ground heat source for direct heating, and fails to fully utilize underground rock layers as heat storage medium, lacking the ability of "summer storage and winter use". It cannot store heat during the non-heating period, and cannot realize on-demand adjustment and heat energy guarantee during the heating period, which restricts the operation flexibility and energy utilization efficiency of the system. Therefore, the present application discloses a heating system based on waste heat recovery of a generator set, which constructs an integrated heating system with the functions of "waste heat recovery-underground heat storage-heat pump temperature increase-intelligent control", realizes cross-season energy transfer and heating peak shaving, and improves the energy utilization efficiency. SUMMARY

[0004] Therefore, the present application aims to provide a heating system based on waste heat recovery of a generator set to solve the problems of insufficient waste heat recovery, weak peak shaving capacity, limited heating coverage and lack of underground heat storage means in the traditional cogeneration heating system.

[0005] To achieve the above purpose, the present application provides a heating system based on waste heat recovery of a generator set, which comprises a waste heat collection unit, a plate heat exchanger and a cooling tower connected in parallel on the circulating pipeline of the condenser of the generator set, and a switching valve group is arranged between the two. The underground energy storage unit comprises a first extraction well and a second extraction well connected by a heat exchange pipeline, the bottom of the first extraction well and the second extraction well are coupled by a high thermal conductivity filling layer, the first extraction well is set as a high-temperature well group, and the second extraction well is set as a low-temperature well group. The heat pump unit comprises a lithium bromide absorption heat pump, the low-temperature heat source inlet of the lithium bromide absorption heat pump is connected in parallel with the outlet of the plate heat exchanger and the water extraction pipeline of the first extraction well. The driving heat source unit comprises a steam pipeline extracted from the cylinder of the generator set and connected to the driving heat source inlet of the lithium bromide absorption heat pump. The intelligent control unit is used for real-time monitoring of the outlet water temperature of the plate heat exchanger, the temperature field of the underground well group and the heating return water temperature, dynamic adjustment of the switching valve group and the heat source mixing ratio, and realization of closed-loop scheduling and heat efficiency optimization of the system.

[0006] Preferably, the high thermal conductivity filling layer is composed of artificial quartz sand and metal thermal conductive particles, the thermal conductivity coefficient of which is 2.5 to 3 times that of the surrounding natural rock layer, and the filling thickness satisfies the relationship H≥0.2D, wherein H is the thickness of the filling layer, and D is the horizontal distance between the first extraction well and the second extraction well.

[0007] Preferably, the operation control of the underground energy storage unit comprises: In the non-heating season, the second extraction well is controlled to extract underground cold water, which is heated by the plate heat exchanger and then reinjected into the first extraction well, wherein the reinjection water temperature rise satisfies ΔT≥η·κ·ln(t / τ), wherein η is the rock heat absorption coefficient, κ is the circulating water waste heat grade parameter, t is the heat storage time, and τ is the system time constant. In the heating season, the first extraction well is controlled to extract high-temperature hot water, which is reinjected into the second extraction well after heat utilization.

[0008] Preferably, the switching valve group comprises a three-way shunt valve and a temperature sensor, when the outlet water temperature of the plate heat exchanger exceeds the condenser allowable temperature, the following shunt ratio is used to guide the flow to the cooling tower: K=[1-( - ) / Δ ]^2, wherein, is the highest temperature allowed by the condenser, is the measured outlet temperature of the heat exchanger, Δ is the maximum tolerable temperature difference of the system.

[0009] Preferably, the driving source of the electric heat pump unit comprises a photovoltaic power input interface and a thermal power plant power input interface, which are used to drive the electric heat pump unit during low electricity price periods or at the end of heat storage to absorb the low-grade waste heat at the outlet of the plate heat exchanger and raise it to high-grade heat energy to meet the requirements of rock stratum heat storage, and then recharge into the first extraction and injection well, wherein the plate heat exchanger is preferentially used for direct heat exchange at the early stage of heat storage, and the electric heat pump is activated when the recharging water temperature of the first extraction and injection well is lower than the threshold of rock stratum heat absorption efficiency at the end of heat storage, so as to realize energy cost optimization and underground temperature gradient improvement, and a heat storage buffer tank is arranged between the underground energy storage unit and the heat pump unit, which is used to temporarily store high-temperature hot water extracted by the first extraction and injection well during the heating season, so as to cut peak and fill valley and adjust the water temperature fluctuation at the inlet of the heat pump, and a flow guide baffle and a layered heat preservation structure are arranged in the heat storage buffer tank, so as to maintain stable stratification of hot water in the tank and reduce heat mixing loss.

[0010] Preferably, the switching valve group is provided with a mechanical linkage adjustment mechanism, which is coupled and controlled by a floating flow divider and a temperature-sensitive expansion element, so as to automatically adjust the flow distribution ratio between the cooling tower and the heat exchanger when the outlet water temperature of the plate heat exchanger rises or the heat exchange flow fluctuates abnormally, thereby forming a self-balancing heat management structure without external signal control, which is used to ensure passive emergency heat dissipation when the control system fails or is overloaded.

[0011] Preferably, the intelligent control unit comprises: a fiber-optic temperature sensor array arranged along the depths of the first extraction and injection well and the second extraction and injection well, which is used to collect the underground temperature field distribution in real time; a temperature field reconstruction module, which calculates the optimal recharge flow Q based on the following model: Q=(2πλL·ΔT) / [ln(R / r0)+σ·(T0)], wherein λ is the rock body thermal conductivity, L is the well depth, ΔT is the design temperature rise, R is the thermal influence radius, r0 is the well radius, σ is the heat loss correction factor, and T0 is the current well bottom temperature.

[0012] Preferably, temperature control check valves are installed at the recharge ports of the first extraction and injection well and the second extraction and injection well, and when the recharge water temperature is lower than the rock stratum safety temperature, the valve opening degree is reduced by 50% and an alarm is triggered.

[0013] Preferably, two-stage pressure reducing valves are arranged in the steam pipeline, and when the steam pressure fluctuation exceeds ±15%, the control system automatically switches to the standby pressure reducing valve to maintain the pressure within the target range.

[0014] Preferably, a redundant heat exchange channel is arranged between the plate heat exchanger and the condenser, and the design flow rate of the redundant heat exchange channel is not less than 80% of that of the main channel, which is used to ensure the safe heat dissipation capacity of the system when the main heat exchanger fails or is insufficient.

[0015] The present application has the following beneficial effects: ​1. The heating system based on waste heat recovery of the generator set, by setting the underground energy storage unit and the switching valve group, the efficient waste heat management and safety control of the system in the whole year operation are realized, in the non-heating season, the system injects the excess heat generated by the generator set into the underground through the energy storage unit, forms a stable heat storage area, provides heat energy guarantee for the heating season, during the heating period, the energy storage system can intelligently switch the roles of pumping and pumping wells according to the well water temperature, ensure that the heating end always extracts high-temperature water, improve the continuity and energy efficiency of heating, at the same time, the switching valve group can realize real-time monitoring and drainage adjustment of the outlet water temperature of the plate heat exchanger, when the heat load is too high, it can be timely shunted to the cooling tower, effectively avoid the overload of the heat exchanger and the heating risk of the condenser, the two work together, ensure the safety of heating, realize the integrated waste heat storage, release and control of the ground and underground, improve the stability, regulation ability and energy comprehensive utilization efficiency of the system.

[0016] 2. The heating system based on waste heat recovery of the generator set, by setting the intelligent control unit, the real-time high-precision monitoring of the underground heat storage is realized through the optical fiber temperature sensor array, the optimal recharge flow is dynamically calculated combined with the temperature field reconstruction model, so that the recharge process is more accurate and efficient. The system can automatically adjust the water injection rate and injection horizon according to the heat pump operation state, heating load and underground temperature distribution, avoid over-heating or early cooling of the formation, effectively guarantee the stability of heat pump heat absorption. At the same time, it has the ability of thermal coupling leveling and boundary early warning, which improves the operation safety, heat storage efficiency and geothermal field control precision of the system under complex working conditions. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present application or prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only a part of the present application, and other drawings can also be obtained by those skilled in the art without creating any creative labor.

[0018] Figure 1 It is a schematic diagram of the working principle of the present application; Figure 2 It is a working flow tree diagram of the present application; Figure 3 It is a schematic diagram of the operation control of the underground energy storage unit of the present application. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the present application more clear, the following will further describe the present application in combination with specific embodiments.

[0020] It should be noted that, unless otherwise defined, technical or scientific terms used in the present application shall have the usual meaning understood by a person with ordinary skill in the art to which the present application belongs. The terms "first", "second" and similar words used in the present application do not represent any order, number or importance, but are only used to distinguish different components. "Including" or "including including" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connected" or "connected" and similar words are not limited to physical or mechanical connection, but can include electrical connection, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to represent relative positional relationship, which may change accordingly when the absolute position of the described object changes.

[0021] As shown in Figures 1 to 3 The heating system based on waste heat recovery of generator set includes a waste heat collection unit, a cooling tower and a plate heat exchanger connected in parallel on the circulating pipeline of the condenser of the generator set, and a switching valve group is arranged between the plate heat exchanger and the cooling tower; an underground energy storage unit including a pumping well one and a pumping well two connected by a heat exchange pipeline to the plate heat exchanger, and the bottom of the pumping well one and the pumping well two are heat-coupled through a high-thermal-conductivity filling layer; a heat pump unit including a lithium bromide absorption heat pump, the low-temperature heat source inlet of which is connected in parallel to the outlet of the plate heat exchanger and the pumping pipeline of the pumping well one; a driving heat source unit including a steam pipeline drawn from the medium-pressure cylinder of the generator set and connected to the driving heat source inlet of the lithium bromide absorption heat pump; and an intelligent control unit for real-time monitoring of the outlet water temperature of the plate heat exchanger, the temperature field of the underground well group and the heating return water temperature, dynamic adjustment of the switching valve group and the heat source mixing ratio, closed-loop scheduling and heat efficiency optimization of the system. In the operation of the system, the high-temperature circulating water on the side of the condenser of the generator set is used as a waste heat source, enters the plate heat exchanger through the intelligent switching valve group, exchanges heat with the low-temperature underground water pumped from the pumping well one, realizes heat recovery and water temperature rise, and if the outlet water temperature of the heat exchanger is detected to exceed the set upper limit, the system automatically switches part of the hot water to the cooling tower for bypass cooling to protect the cold end safety of the condenser, the heated water can be directly used for heating or partially stored in the underground heat storage system, the lithium bromide absorption heat pump in the system uses the low-temperature water mixed by the plate heat exchanger and the well water as the absorption heat source, and the steam drawn from the medium-pressure cylinder as the driving heat source, and after completing the step-up of the heat, high-grade hot water is delivered to the building end, while the intelligent control system constructs an operation heat balance model according to the three data of the outlet temperature of the plate heat exchanger, the well water temperature and the user return water temperature, and dynamically coordinates the multiple sources by adjusting the heat source path ratio, the supply and return water temperature difference and the valve group opening degree, so as to realize the preferential use of waste heat, fine matching of heating load and optimization of heat exchange link energy efficiency.

[0022] The high-thermal-conductivity filling layer is composed of artificial quartz sand and metal thermal-conductivity particles, and has a thermal conductivity 2.5 to 3 times that of the surrounding natural rock layer, and a filling thickness satisfying the relationship H≥0.2D, wherein H is the filling layer thickness, and D is the horizontal distance between the first and second pumping wells; In the construction phase, the bottom area between the two pumping wells is filled with a high-thermal-conductivity material layer composed of artificial quartz sand and metal thermal-conductivity particles, which has a thermal conductivity 2.5 to 3 times that of the surrounding rock layer, and a filling thickness H satisfying the relationship H≥0.2D, so as to ensure that the heat coupling path at the well bottom is wide and thick enough, and the heat transfer flux is sufficient. In operation, when the heated water from the second pumping well is recharged into the underground, the heat is efficiently conducted along the filling layer to the rock layer area of the first pumping well, improving the heat storage capacity thereof, so as to realize continuous heat field transmission under seasonal alternation, reduce the heat deviation phenomenon of the well group, and enhance the response speed of the underground heat storage.

[0023] As shown in Figure 2 , Figure 3 , the operation control of the underground energy storage unit includes: In the non-heating season, the second pumping well is controlled to extract cold water from the underground, which is recharged into the first pumping well after being heated by the plate heat exchanger, wherein the temperature rise of the recharged water satisfies ΔT≥η·κ·ln(t / τ), wherein η is the heat absorption coefficient of the rock layer, κ is the waste heat grade parameter of the circulating water, t is the heat storage time, and τ is the system time constant; In the heating season, the first pumping well is controlled to extract high-temperature hot water, which is recharged into the second pumping well after heat utilization; In the non-heating season, the underground heat storage operation strategy is enabled, cold water is extracted from the second pumping well and sent to the plate heat exchanger for heating, and the heated water is recharged into the first pumping well, and the hot water diffuses in the underground rock layer and stores heat; this process satisfies the temperature rise model: ΔT≥η·κ·ln(t / τ); The model is used to determine whether the heat storage cycle is effective, and if the condition is not met, the flow rate is automatically adjusted or the operation time is extended. When the heating season comes, if the current water temperature of the pumping well is lower than the set threshold, the system automatically switches the roles of the well group, uses the well with better heat storage as the heat supply source, and maintains the persistence of the hot water temperature in the heating period; Specifically, in the non-heating season, the system starts the underground heat storage mode according to the set calendar strategy, selects the second pumping well as the pumping well to extract low-temperature well water and guide it through the plate heat exchanger to recover the waste heat of the generator set, so that the water temperature rises rapidly and is recharged into the underground energy storage area by the first pumping well. The hot water diffuses and stores in the rock mass around the well, and is transferred to the heat storage area of the second pumping well through the thermal-conductivity filling layer, forming a symmetrical and stable state of the heat field. After entering the heating season, the system first extracts water from the first pumping well, and the high-temperature water is recharged into the second pumping well after heat utilization; The switching valve assembly includes a three-way diverter valve and a temperature sensor. When the outlet water temperature of the plate heat exchanger exceeds the allowable temperature of the condenser, water is diverted to the cooling tower according to the following diversion ratio: K=[1-( - ) / Δ ]^2, where, This is the highest permissible temperature for the condenser. To measure the heat exchanger outlet temperature, Δ This represents the system's maximum tolerable temperature difference. During normal operation of the generator set and the introduction of circulating hot water from the condenser side into the plate heat exchanger, the system monitors the difference between the outlet water temperature and the allowable temperature of the condenser in real time. If the temperature approaches or exceeds the upper limit, the intelligent control system quickly calculates the proportion of water that needs to be diverted based on the temperature difference change curve and controls the three-way diversion valve to automatically adjust its opening, allowing a portion of the high-temperature hot water to enter the cooling tower branch for emergency cooling. This diversion process does not interrupt normal heating; it only diverts a portion of the flow to the cooling channel to ensure that the plate heat exchanger end does not overheat and the cold end does not overcool, while maintaining the system pressure difference and loop balance. This intelligent response mechanism can achieve millisecond-level adjustment and has high-frequency control and fault isolation functions, which are important guarantees for system stability and fault redundancy.

[0024] like Figures 1 to 3 As shown, the drive source of the electric heat pump unit includes a photovoltaic power input interface and a thermal power plant power input interface. It is used to drive the electric heat pump unit during periods of low electricity prices in the non-heating season or at the end of the thermal storage phase. This absorbs the low-grade waste heat from the plate heat exchanger outlet and elevates it to a high-grade thermal energy that meets the requirements of rock formation thermal storage before reinjecting it into the first production and injection well. In the early stage of thermal storage, the plate heat exchanger is used for direct heat exchange. At the end of the thermal storage phase, when the reinjection water temperature in the first production and injection well is lower than the rock formation's thermal absorption efficiency threshold, the electric heat pump is activated to optimize energy costs and enhance the underground temperature gradient. A thermal storage buffer tank is installed between the underground energy storage unit and the heat pump unit unit for... During the heating season, high-temperature hot water extracted from the intake and irrigation well is temporarily stored to smooth out peak and valley water temperature fluctuations at the heat pump inlet. The heat storage buffer tank is equipped with a flow guide baffle and a layered insulation structure to maintain stable stratification of hot water in the tank and reduce heat mixing losses. The switching valve group is equipped with a mechanical linkage adjustment mechanism, which is coupled and controlled by a floating flow divider and a temperature-sensitive expansion element. When the outlet water temperature of the plate heat exchanger rises or the heat exchange flow fluctuates abnormally, the flow ratio between the cooling tower and the heat exchanger is automatically adjusted to form a self-balancing thermal management structure that does not require external signal control, and is used to ensure passive emergency heat dissipation in the event of control system failure or overload. The electric heat pump unit is started in the low electricity price period or the heat storage end period in the non-heating season, and the photovoltaic electricity or the power plant electricity drives the unit to operate through a special interface, absorbs the low-grade waste heat output by the plate heat exchanger, and is injected into the group of high-temperature wells after the heat energy grade is improved; the system preferentially adopts the direct heat exchange mode of the plate heat exchanger in the early heat storage period, and automatically activates the electric heat pump intervention when it is monitored that the water temperature of the injection and extraction well is lower than the rock heat absorption efficiency threshold, so that the underground temperature gradient optimization and energy consumption cost control are realized; in the process, the heat storage buffer tank temporarily stores the high-temperature hot water extracted from the injection and extraction well, and the internal flow guide baffle and the layered heat preservation structure are used to stabilize the water temperature fluctuation, and the switching valve group is adjusted by the mechanical linkage mechanism to realize passive emergency heat dissipation relying on the floating flow distribution plate and the temperature sensitive element coupling, so that a full working condition heat management closed loop is formed. During the operation period in the heating season, the high-temperature hot water extracted from the injection and extraction well first enters the heat storage buffer tank, the flow guide baffle guides the water flow to form a stable laminar flow along the tank wall, the high-temperature water accumulates at the upper part of the tank body, and the low-temperature water settles at the bottom, and the layered heat preservation structure maximally reduces the radial heat diffusion; when the heat pump unit needs to supplement the heat source, the high-temperature water at the upper part of the buffer tank is delivered to the low-temperature inlet of the heat pump through the constant flow valve, if the water temperature abnormally rises or the flow fluctuates due to sudden increase of heat load, the mechanical linkage mechanism immediately responds: the temperature sensitive expansion element is deformed by heat, pushes the floating flow distribution plate to deflect, increases the flow distribution proportion to the cooling tower, and at the same time reduces the flow of the plate heat exchanger passage, so that a negative feedback regulation is formed until the water temperature returns to the safe interval; this process is completely realized by the mechanical structure without the intervention of the control unit, so that the condenser circulation heat dissipation safety can be maintained when the control system is overloaded, and the buffer tank is continuously connected with the injection and extraction well through the low-temperature water outlet at the bottom and the injection and extraction well injection pipeline, so that the water body circulation renewal and heat stratification stable maintenance in the tank are realized. The intelligent control unit comprises: The optical fiber temperature sensor array arranged along the depth of the injection and extraction well and the injection and extraction well two is used for collecting the underground temperature field distribution in real time; The temperature field reconstruction module calculates the optimal injection flow Q based on the following model: Q=(2πλL·ΔT) / [ln(R / r0)+σ·( -T0)], wherein λ is the rock thermal conductivity, L is the well depth, ΔT is the design temperature rise, R is the thermal influence radius, r0 is the well radius, and σ is the heat loss correction factor; The optical fiber temperature sensor array arranged along the depth of the injection and extraction well and the injection and extraction well two is arranged every several meters to form a high-resolution underground temperature profile, the intelligent control unit reconstructs a three-dimensional underground heat field model by collecting data in real time, and based on this, the following formula is used to calculate the current optimal injection flow: Q: Q=(2πλL·ΔT) / [ln(R / r0)+σ·( The model combines the changes in the underground temperature field and the target heat output to automatically calculate the most reasonable water injection rate and adjust the execution valve group, so that the formation is neither overheated nor prematurely cooled, ensuring stable heat pump heat absorption, avoiding system efficiency decline caused by geothermal fluctuations. Specifically, the intelligent control unit collects multi-layer temperature data of the wellbore and surrounding thermal reservoirs in real time through the fiber-optic temperature sensor array deployed at different depths in the production and injection wells, and uses these data to build a three-dimensional model of the underground temperature field. Then, through the temperature field reconstruction algorithm, the current best reinjection flow rate and stratified injection strategy are dynamically calculated by comparing the theoretical design temperature rise with the actual measured temperature. The reinjection rate can be adjusted in real time by referring to the heating load, heat pump operating status, and return water temperature difference, achieving composite control of "overheating protection", "thermal coupling leveling", "boundary early warning", etc. in the thermal reservoir area, so that the entire underground energy storage unit always operates on the optimal heat storage efficiency curve under different working conditions.

[0025] As shown in Figure 1 , Figure 2 , the reinjection openings of the production and injection wells one and two are installed with temperature-controlled check valve groups. When the reinjection water temperature is less than the rock formation safety temperature, the valve opening is reduced by 50% and an alarm is triggered. Two-stage pressure reducing valves are provided in the steam pipeline. When the steam pressure fluctuation exceeds ±15%, the control system automatically switches to the standby pressure reducing valve to maintain the pressure within the target range. A redundant heat exchange channel is provided between the plate heat exchanger and the condenser, with a design flow rate not less than 80% of the main channel, to ensure the safety of the system's heat dissipation capacity in case of failure or insufficient efficiency of the main heat exchanger. The installation of temperature-controlled check valve groups dynamically adjusts the reinjection water temperature (reduces the opening by 50% when the temperature is less than the rock formation safety temperature and triggers an alarm), actively blocks the risk of thermal shock cracking of the formation by cold water, maintains the temperature of the thermal reservoir area to ensure that the water temperature meets the standards during the heating season, and reduces the thermal stress of the rock mass to prevent structural collapse. The alarm system realizes zero-accident rate of low-temperature reinjection, enhances the geological safety of the system through hardware-level automatic protection, and prolongs the service life of the underground energy storage unit. At the same time, the medium-pressure steam from the high-temperature source side of the system is stabilized into the heat pump drive end through the two-stage pressure reducing valves installed on the main channel. When the steam pressure fluctuation exceeds ±15%, the standby pressure reducing valve is automatically put into operation to protect the heat pump absorbent from overpressure interference. If the main plate heat exchanger is abnormal due to blockage, dirt, or efficiency decay, the system will immediately switch to the pre-set redundant heat exchange channel, which has a design flow rate not less than 80% of the main path, with the ability to quickly take over and carry heat, and can complete the heat task connection without affecting the stable operation of the main system, serving as an important guarantee module for system operation stability and safety redundancy.

[0026] Those skilled in the art should understand that the above discussion of any embodiment is only intended to be illustrative and is not intended to be in any way limiting to the scope of the present application, including the claims that follow it; the above embodiments or technical features among different embodiments can also be combined, steps can be implemented in any order, and there are many other changes to the different aspects of the present application as described above, which are not provided in detail for the sake of brevity.

[0027] The present application is intended to cover all such alternatives, modifications, and variations as come within the scope of the broadest possible interpretation of the appended claims. Accordingly, any and all such alternatives, modifications, equivalents, improvements and the like are intended to be encompassed by the present application.

Claims

1. A heating system based on waste heat recovery from a generator set, characterized in that, The application relates to a waste heat collection unit, an underground energy storage unit, a heat pump unit, a driving heat source unit and an intelligent control unit. The underground energy storage unit comprises a first extraction well and a second extraction well connected by a heat exchange pipeline, the bottom of the first extraction well and the second extraction well are coupled by a high-thermal-conductivity filling layer, the first extraction well is arranged as a high-temperature well group, and the second extraction well is arranged as a low-temperature well group. The heat pump unit comprises a lithium bromide absorption heat pump, the low-temperature heat source inlet of the lithium bromide absorption heat pump is connected in parallel with the outlet of the plate heat exchanger and the water extraction pipeline of the first extraction well. The driving heat source unit comprises a steam pipeline extracted from a middle pressure cylinder of a power generating unit and connected to the driving heat source inlet of the lithium bromide absorption heat pump. The intelligent control unit is used for monitoring the outlet water temperature of the plate heat exchanger, the temperature field of the underground well group and the heating return water temperature in real time, dynamically adjusting the switching valve group and the heat source mixing ratio, and realizing closed-loop scheduling and heat efficiency optimization of the system. The high-thermal-conductivity filling layer is composed of artificial quartz sand and metal thermal conductive particles, the thermal conductivity coefficient of the high-thermal-conductivity filling layer is 2.5 to 3 times that of the surrounding natural rock layer, and the filling thickness satisfies the relationship H >= 0.2D, wherein H is the thickness of the filling layer, and D is the horizontal distance between the first extraction well and the second extraction well.

2. The heating system based on waste heat recovery of a generator set according to claim 1, characterized in that, The operation control of the underground energy storage unit comprises the following steps:

3. The heating system based on waste heat recovery of a generator set according to claim 1, characterized in that, In a non-heating season, the second extraction well is controlled to extract underground cold water, the cold water is heated through the plate heat exchanger and then is injected into the first extraction well, and the water temperature rise of the injection satisfies the relationship Delta T >= eta * kappa * ln (t / tau), wherein eta is a rock layer heat absorption coefficient, kappa is a circulating water waste heat grade parameter, t is a heat storage time length, and tau is a system time constant. In a heating season, the first extraction well is controlled to extract high-temperature hot water, the hot water is used for heat utilization and then is injected into the second extraction well. The driving source of the electric heat pump unit comprises a photovoltaic electric input interface and a thermal power plant electric input interface, which are used for driving the electric heat pump unit in a low electricity price period or a heat storage end period in the non-heating season, so that the low-grade waste heat of the outlet of the plate heat exchanger is absorbed, the high-grade heat energy is lifted to meet the rock layer heat storage requirement, and then is injected into the first extraction well.

4. The heating system based on waste heat recovery of a generator set according to claim 1, characterized by, The switching valve group contains a three-way diverter valve and a temperature sensor that diverts to the cooling tower in the following split ratio when the plate heat exchanger outlet water temperature exceeds the condenser allowable temperature: K=[1-( - ) / Δ ]^2, where, is the maximum condenser allowable temperature, is the measured heat exchanger outlet temperature, Δ is the maximum system tolerable temperature difference.

5. The heating system based on waste heat recovery of a generator set according to claim 1, characterized in that, The underground energy storage unit and the heat pump unit are provided with a heat storage buffer tank for temporarily storing the high-temperature hot water extracted from the first extraction well during the heating season, so as to cut the peak and fill the valley and adjust the water temperature fluctuation of the heat pump inlet.

6. The heating system based on waste heat recovery of a generator set according to claim 1, characterized by, The switching valve group is provided with a mechanical linkage adjusting mechanism, the mechanism is coupled and controlled by a floating type flow divider and a temperature sensitive expansion element, when the outlet water temperature of the plate heat exchanger is increased or the heat exchange flow fluctuation is abnormal, the flow distribution ratio between the cooling tower and the heat exchanger is automatically adjusted, a self-balancing heat management structure without external signal control is formed, and passive emergency heat dissipation is guaranteed when the control system fails or is overloaded.

7. The heating system based on waste heat recovery of a generator set according to claim 1, characterized by, The intelligent control unit comprises the following steps: An array of optical fiber temperature sensors is arranged along the depth of the first and second extraction wells to collect the temperature field distribution in real time. The temperature field reconstruction module calculates the optimal reinjection flow rate Q based on the following model: Q=(2πλL·ΔT) / [ln(R / r0)+σ·( -T0)], where λ is the thermal conductivity of the rock mass, L is the well depth, ΔT is the design temperature rise, R is the radius of thermal influence, r0 is the well radius, σ is the heat loss correction factor, and T0 is the current bottom hole temperature.

8. The heating system based on waste heat recovery of a generator set according to claim 1, characterized by, A temperature control check valve set is installed at the recharge outlets of the first and second extraction wells. When the recharge water temperature is less than the safe temperature of the rock stratum, the valve opening is reduced by 50% and an alarm is triggered.

9. The heating system based on waste heat recovery of a generator set according to claim 1, characterized by, Two-stage pressure reducing valves are provided in the steam pipeline. When the steam pressure fluctuation exceeds ±15%, the control system automatically switches to the standby pressure reducing valve to maintain the pressure within the target range.

10. The heating system based on waste heat recovery of a generator set according to claim 1, characterized by, A redundant heat exchange channel is provided between the plate heat exchanger and the condenser, with a design flow rate not less than 80% of the main channel, to ensure the safe heat dissipation capacity of the system in case of failure or insufficient efficiency of the main heat exchanger.

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