Workshop heating system utilizing waste heat of turbid circulating water and control method of workshop heating system

Abstract

The invention provides a workshop heating system utilizing turbid circulating water waste heat and a control method thereof, relates to the technical field of nonferrous metal production, and mainly aims to solve the problem that turbid circulating water cannot stably supply heat in the prior art. The workshop heating system comprises a turbid circulation system, a heat pump, an auxiliary heating system and a heating coil installed in a workshop. Wherein the turbid circulating system takes production equipment as a heat source and turbid circulating water as a heat-conducting medium, and provides basic heat energy for the heating coil pipe through a heat pump; the auxiliary heating system uses the gas-fired boiler as a heat source and provides auxiliary heat energy with adjustable temperature for the heating coil pipe. According to the workshop heating system control method, operation of all the devices is divided into four stages, the startup and shutdown conditions of the heat pump, the cooling tower and the gas-fired boiler are defined, 42-50 DEG C heating water can be stably and efficiently provided for a workshop, and energy consumption and heat energy waste are reduced to the maximum extent.

Description

Technical Field

[0001] This invention specifically relates to a workshop heating system and its control method that utilizes waste heat from turbid circulating water, and pertains to the field of non-ferrous metal production technology. Background Technology

[0002] In the non-ferrous metal processing industry, turbid circulating water is used to cool the ingots after casting, which results in a significant amount of heat energy in this water. To reuse this water for ingot cooling, cooling towers are required, leading to substantial heat energy waste. While existing technologies can utilize the heat energy of the turbid circulating water for workshop heating, its temperature fluctuates with seasonal changes and production volume, often failing to meet the requirements for stable workshop heating. Summary of the Invention

[0003] To overcome the shortcomings of the prior art, this invention discloses a workshop heating system and its control method utilizing waste heat from turbid circulating water, employing the following technical solution: A workshop heating system utilizing waste heat from turbid circulating water includes a turbid circulating system, a heat pump, an auxiliary heating system, and heating coils installed in the workshop. The turbid circulating system uses production equipment as a heat source and turbid circulating water as a heat transfer medium, providing basic heat energy to the heating coils through the heat pump. The auxiliary heating system uses a gas-fired boiler as a heat source, providing auxiliary heat energy with adjustable temperature to the heating coils.

[0004] Further improvements to the technical solution: The turbid circulation system mainly consists of a cold water tank, a hot water tank, a cold water pump, a hot water pump, a cooling tower, a heat source-side circulation pump, and heat source-side water treatment equipment.

[0005] Further improvements to the technical solution: The heat pump includes an evaporator and a condenser, the evaporator is connected to the turbid circulation system, and the condenser is connected to the heating coil.

[0006] Further improvements to the technical solution: The auxiliary heating system mainly consists of a gas boiler, a boiler water supply device, an auxiliary heating side circulation pump, and a heating end circulation pump.

[0007] Further improvements to the technical solution: A temperature sensor T1 and a heat meter R1 are installed at the output end of the heat pump; a temperature sensor T2 and a heat meter R2 are installed at the input end of the heating coil; a temperature sensor T3 and a heat meter R3 are installed at the end where the turbid circulation system is connected to the production equipment; a temperature sensor T4 is installed on the inlet pipe of the hot water pump; a temperature sensor T5 is installed on the outlet pipe of the cooling tower; and a heat meter R4 is installed at the end where the heat pump is connected to the turbid circulation system.

[0008] A control method for a workshop heating system, wherein the workshop heating system comprises three heat pumps, three cooling towers, and two gas-fired boilers, and the control method includes the following start-up and shutdown conditions: Let the heating capacity of a single heat pump be Q. D When R3 < Q D When T3 < 30℃, the heat pump does not operate; when Q D <R3<2Q D When T3 > 30℃, the first heat pump starts operating; when 2Q D <R3<3Q D When T3 > 30℃, the second heat pump operates; when 3Q D When R3 < 30℃ and T3 > 30℃, the third heat pump will start; when shutting down, the process will proceed in reverse order. Let the heat dissipation of a single cooling tower be Q. E When R3-R4≤0 and T5<30℃, the cooling towers will not operate; when 0<R3-R4<Q E When T5 = 30℃, the first cooling tower is turned on; when Q E <R3-R4<2Q E When T5 = 30℃, start the second cooling tower; when 2Q E <R3-R4<3Q E When T5=30℃, turn on the third cooling tower; turn off the tower in the reverse order. Let Q be the heat required by the workshop. A When R² = 0 < Q A At the same time, when T2 < 50℃, both gas-fired boilers operate simultaneously.

[0009] Further improve the technical solution: the start-up conditions of the heat pump take precedence over those of the cooling tower.

[0010] Further improve the technical solution: Let the heat provided by the heat pump be Q. B The heat provided by the gas-fired boiler is Q. C Then Q A =(1.1-1.15)(Q) B +Q C ).

[0011] After implementing the above technical solution, the beneficial effects of this invention compared to the prior art are as follows: The workshop heating system of the present invention uses the waste heat of the sludge circulation system as the basic heat energy and the gas boiler as the auxiliary heat energy, which can stably and efficiently provide the workshop with heating water at 42-50℃.

[0012] The workshop heating system control method of the present invention divides the operation of each device into four stages and clarifies the start-up and shutdown conditions of heat pumps, cooling towers and gas boilers, thereby minimizing energy consumption and heat waste. Attached Figure Description

[0013] Appendix Figure 1 The diagram shown is a structural schematic of the heating system in this workshop.

[0014] Appendix Figure 2 The diagram shown is a schematic of the turbid circulation system.

[0015] Appendix Figure 3 The diagram shows the structure of the boiler unit and the heat pump unit.

[0016] Appendix Figure 4 The diagram shown is a schematic of a heat pump. Detailed Implementation

[0017] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these preferred embodiments are merely for explaining the technical principles of the present invention and are not intended to limit the scope of protection of the present invention. It should be noted that in the description of the present invention, terms such as "front," "rear," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," which indicate direction or positional relationships, are based on the direction or positional relationships shown in the accompanying drawings. This is merely for ease of description and does not indicate or imply that the device or component must have a specific orientation and positional relationship, and therefore should not be construed as a limitation of the present invention. It should also be noted that in the description of the present invention, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral connection; it can refer to a mechanical connection or an electrical connection; it can refer to a direct connection or an indirect connection through an intermediate medium, or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0018] A workshop heating system utilizing waste heat from turbid circulating water is disclosed, relating to the field of non-ferrous metal production technology. It primarily addresses the problem in existing technologies where the temperature of turbid circulating water fluctuates with seasonal changes and production volume, preventing the provision of constant-temperature heating. The composition and working principle of this invention are described in detail below.

[0019] See attached document Figure 1-3 The workshop heating system of the present invention includes a turbid circulation system, a heat pump, an auxiliary heating system, and heating coils installed in the workshop. The turbid circulation system uses production equipment as a heat source and turbid circulating water as a heat transfer medium, providing basic heat energy to the heating coils via the heat pump. The auxiliary heating system uses a gas-fired boiler as a heat source, providing auxiliary heat energy with adjustable temperature to the heating coils.

[0020] Specifically, the turbid circulating system mainly consists of a cold water tank, a hot water tank, a cold water pump, a hot water pump, a cooling tower, a heat source-side circulating pump, and heat source-side water treatment equipment. The turbid circulating water in the cold water tank is connected to non-ferrous metal production equipment, including casting machines, via pipelines, and generates significant heat energy after cooling the equipment. To utilize the waste heat from the turbid circulating system, the turbid circulating water in the hot water tank is connected to a heat pump via pipelines, which provides basic heat energy to the heating coils.

[0021] See attached document Figure 4 A heat pump is a device that transfers heat energy from a low-temperature heat source to a high-temperature heat source. It mainly consists of a compressor, condenser, expansion valve, evaporator, and reversing valve. Typically, a heat pump has a COP of 3-4, meaning it can transfer 3-4 times its own required energy from a low-temperature object to a high-temperature object, resulting in significant energy savings. In this embodiment, the evaporator is connected to the refrigerant circulation system, and the condenser is connected to the heating coil (radiator). During operation, the high-pressure refrigerant vapor discharged from the compressor flows into the evaporator through the reversing valve. The refrigerant vapor releases a large amount of latent heat upon condensation, which heats the heating coil through heat exchange. The condensed liquid refrigerant then flows in the reverse direction through the expansion valve into the condenser, where it absorbs heat from the refrigerant circulation system and evaporates. The evaporated vapor is then drawn into the compressor through the reversing valve, completing the heating cycle.

[0022] Because the temperature of the circulating water in the turbid circulation system varies with the seasons and production volume, the temperature fluctuations after being heated by the heat pump are significant, failing to meet the requirements for constant temperature heating. Therefore, an auxiliary heating system is needed to improve the stability of the heating system. In this embodiment, the auxiliary heating system mainly consists of two gas-fired boilers, a boiler water supply device, multiple auxiliary heating-side circulation pumps, and a heating-side circulation pump. Compared to the turbid circulation system, the gas-fired boilers use natural gas as fuel, and the heat generated is easily controlled. When the heat generated by the heat pump is low, the heat generated by the gas-fired boiler can be increased; when the heat generated by the heat pump is high, the heat generated by the gas-fired boiler can be decreased, thereby meeting the requirements for constant temperature heating.

[0023] In this embodiment, the workshop heating system includes three heat pumps, three cooling towers, and two gas-fired boilers. For ease of control, a temperature sensor T1 and a heat meter R1 are installed at the output end of the heat pumps; a temperature sensor T2 and a heat meter R2 are installed at the input end of the heating coils; a temperature sensor T3 and a heat meter R3 are installed at the end of the turbid circulation system connected to the production equipment; a temperature sensor T4 is installed on the inlet pipe of the hot water pump; a temperature sensor T5 is installed on the outlet pipe of the cooling towers; and a heat meter R4 is installed at the end of the heat pump connected to the turbid circulation system.

[0024] A control method for a workshop heating system, comprising four operating phases and including the following start-up and shutdown conditions: Let the heating capacity of a single heat pump be Q.D When R3 < Q D When T3 < 30℃, the heat pump does not operate; when Q D <R3<2Q D When T3 > 30℃, the first heat pump starts operating; when 2Q D <R3<3Q D When T3 > 30℃, the second heat pump operates; when 3Q D When R3 < 30℃ and T3 > 30℃, the third heat pump will start; when shutting down, the process will proceed in reverse order. Let the heat dissipation of a single cooling tower be Q. E When R3-R4≤0 and T5<30℃, the cooling towers will not operate; when 0<R3-R4<Q E When T5 = 30℃, the first cooling tower is turned on; when Q E <R3-R4<2Q E When T5 = 30℃, start the second cooling tower; when 2Q E <R3-R4<3Q E When T5=30℃, turn on the third cooling tower; turn off the tower in the reverse order. Let Q be the heat required by the workshop. A When R² = 0 < Q A At the same time, when T2 < 50℃, both gas-fired boilers operate simultaneously.

[0025] The first operational phase: This phase includes the period from the start of the project to the start of operation of the circulating water pumping station, i.e., before the first heat pump is operational, during which only the gas-fired boiler is running. During this time, only the heat source-side circulating pump and the auxiliary heat-side circulating pump are operational.

[0026] After the control system is turned on and all equipment is confirmed to be functioning normally, the indoor heating temperature is first set to 5℃ (at this point, only the operating temperature of each workshop is required), combined with the outdoor temperature T. w Calculate the required Q A Comparing the obtained result with R², since R² = 0 < Q at this point... A Simultaneously, when T2 < 50℃, the controller issues a command to start all gas boilers, and the entire heating system's load is supplied by the gas boilers. Since R3 and T3 cannot meet the start-up conditions for a single heat pump at this time, the heat pumps cannot start, and similarly, the cooling towers cannot start either.

[0027] As the water temperature gradually rises to 50℃, the temperature difference between the supply and return water will be less than 5℃ due to the larger circulating water volume compared to normal heating. Simultaneously, the output of the gas boiler will adjust according to Q. A The actual size gradually increases from zero to the maximum.

[0028] Issues to be aware of during this stage: Q should be minimized.A This reduces energy consumption and the installed capacity of gas-fired boilers. Simultaneously, since no process equipment is in operation, the cold water pump, hot water pump, and heat source-side circulation pump can be shut down.

[0029] The second operational phase: This phase refers to the period from the normal operation of the gas boiler to the commissioning of the first heat pump. During this time, the heat pump and the gas boiler operate simultaneously, and the heating-side circulation pump, the heat source-side circulation pump, the cold water pump, and the hot water pump are all activated.

[0030] With the gradual commissioning of workshops and equipment, Q A R3, T3, and T5 will all gradually increase, and several cooling towers will be activated accordingly. When the operating conditions of the first heat pump are met (Q... D <R3<2Q D Once the temperature reaches 30℃ (T3 > 30℃) and stabilizes for a period of time (t1), the first heat pump will be put into operation. At this time, the cooling tower will be shut down accordingly.

[0031] The controller calculates and determines Q at this time. A With (1.1-1.15)(Q) B +Q C The size of the gas boiler is then determined. The output of the gas boiler will gradually decrease as the first heat pump is put into operation. T2 will stabilize at 50℃ after fluctuations, and the supply and return water temperature difference will increase compared to the first stage, but will still be less than 5℃. Due to the operation of the first heat pump, the number of cooling towers opened will decrease, but the water temperature will stabilize below 30℃.

[0032] Points to note during this stage: Before the heat pump is put into use, the gas boiler can be turned off to lower the water supply temperature, so as to avoid the high outlet water temperature being detrimental to the terminal equipment after the heat pump starts working.

[0033] The third operational phase: This phase refers to the period when the second and third heat pumps are successively put into operation, and the gas boiler is gradually shut down. During this time, the heating-side circulation pump, the heat source-side circulation pump, the cold water pump, and the hot water pump are turned on, the second and third heat pumps are put into operation successively, and the gas boiler is gradually shut down. T2 will stabilize at 50℃ after fluctuations, and the supply and return water temperature difference will stabilize at 5℃.

[0034] Heat pumps consume a significant portion of the energy in heating systems; therefore, maximizing the COP (Coefficient of Performance) of the heat pump unit is the primary basis for setting the inlet and outlet water temperatures. The general trend is to reduce the temperature difference between the heat source and the outlet water, i.e., to raise the supply water temperature of the circulating system as much as possible while lowering the outlet water temperature at the terminal side. According to calculations by one manufacturer, their heat pump unit achieves its highest COP, approximately 8.3, when the supply and return water temperatures at the heat source side are 30 / 38℃ and at the terminal side are 50 / 45℃. When determining these temperatures, it's also important to avoid excessive circulating water volume, which could increase the energy consumption of the circulating pump.

[0035] Points to note during this stage: The start-up conditions for the heat pump take precedence over those for the cooling tower.

[0036] Fourth operating stage: This stage is a flexible adjustment stage, in which each device automatically adjusts according to its own start-up conditions.

[0037] It is worth noting that the content not described in detail in the above embodiments is prior art. It is also worth noting that any additions, subtractions, substitutions, and improvements made by those skilled in the art within the structure and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A workshop heating system utilizing waste heat from turbid circulating water, characterized in that: It includes a turbid circulation system, a heat pump, an auxiliary heating system, and heating coils installed in the workshop; the turbid circulation system uses the production equipment as a heat source and turbid circulating water as a heat transfer medium, and provides basic heat energy to the heating coils through the heat pump; the auxiliary heating system uses a gas boiler as a heat source and provides auxiliary heat energy with adjustable temperature to the heating coils.

2. The workshop heating system utilizing waste heat from turbid circulating water as described in claim 1, characterized in that: The turbidity circulation system mainly consists of a cold water tank, a hot water tank, a cold water pump, a hot water pump, a cooling tower, a heat source-side circulation pump, and heat source-side water treatment equipment.

3. A workshop heating system utilizing waste heat from turbid circulating water as described in claim 1, characterized in that: The heat pump includes an evaporator and a condenser. The evaporator is connected to the circulating system, and the condenser is connected to the heating coil.

4. A workshop heating system utilizing waste heat from turbid circulating water as described in claim 1, characterized in that: The auxiliary heating system mainly consists of a gas-fired boiler, a boiler water supply device, an auxiliary heating side circulation pump, and a heating end circulation pump.

5. A workshop heating system utilizing waste heat from turbid circulating water as described in claim 2, characterized in that: A temperature sensor T1 and a heat meter R1 are installed at the output end of the heat pump; a temperature sensor T2 and a heat meter R2 are installed at the input end of the heating coil; a temperature sensor T3 and a heat meter R3 are installed at the end where the turbid circulation system is connected to the production equipment; a temperature sensor T4 is installed on the inlet pipe of the hot water pump; a temperature sensor T5 is installed on the outlet pipe of the cooling tower; and a heat meter R4 is installed at the end where the heat pump is connected to the turbid circulation system.

6. A control method applied to the workshop heating system as described in claim 5, characterized in that: The workshop heating system has three heat pumps, three cooling towers, and two gas-fired boilers. The control method includes the following start-up and shutdown conditions: Let the heating capacity of a single heat pump be Q. D When R3 < Q D When T3 < 30℃, the heat pump does not operate; when Q D <R3<2Q D When T3 > 30℃, the first heat pump starts operating; when 2Q D <R3<3Q D When T3 > 30℃, the second heat pump operates; when 3Q D When R3 < 30℃ and T3 > 30℃, the third heat pump will start; when shutting down, the process will proceed in reverse order. Let the heat dissipation of a single cooling tower be Q. E When R3-R4≤0 and T5<30℃, the cooling towers will not operate; when 0<R3-R4<Q E When T5 = 30℃, the first cooling tower is turned on; when Q E <R3-R4<2Q E When T5 = 30℃, start the second cooling tower; when 2Q E <R3-R4<3Q E When T5=30℃, turn on the third cooling tower; turn off the tower in the reverse order. Let Q be the heat required by the workshop. A When R² = 0 < Q A At the same time, when T2 < 50℃, both gas-fired boilers operate simultaneously.

7. The control method as described in claim 6, characterized in that: The start-up conditions for heat pumps take precedence over those for cooling towers.

8. The control method as described in claim 6, characterized in that: Let the heat provided by the heat pump be Q. B The heat provided by the gas-fired boiler is Q. C Then Q A =(1.1-1.15)(Q) B +Q C ).

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