Fan coil air-conditioning water system with steam condensate as heat source

Abstract

A steam condensate subsystem of the fan coil air-conditioning water system is used for recycling condensate of a production device in an industrial plant or a combined air-conditioning unit in an air-conditioning machine room with low-pressure steam as the heat source; the air-conditioning hot water subsystem is used for providing a heat source for the air-conditioning terminal under the working condition in winter; the steam subsystem is used for providing heat supply loads needed by the air conditioner water system under the working condition in winter. A water replenishing and pressure stabilizing device of the hot water subsystem adopts a variable-frequency automatic water replenishing pump to replenish water and stabilize pressure, and the water replenishing and pressure stabilizing device of the hot water subsystem serves as a water replenishing source through a steam condensate subsystem; the PLC control subsystem is used for providing a control circuit and a control implementation operation instruction for the air conditioner hot water subsystem; the air conditioner cold water subsystem is used for providing a cold source for the air conditioner terminal under the summer working condition. The defect that the steam condensate water in the industrial plant is directly discharged is overcome, energy conservation and emission reduction are greatly achieved, the low-grade heat energy utilization rate of the steam condensate water in the industrial plant is greatly increased, and the obvious energy-saving and synergistic effects are achieved.

Description

Technical Field

[0001] The invention belongs to the field of waste heat utilization of steam condensed water in industrial plants and design of central air-conditioning water systems, and in particular relates to a fan coil air-conditioning water system whose heat source is steam condensed water. Background Art

[0002] In industrial buildings, such as industrial plants for polyester filament, polyester staple fiber, spandex and polyester film in the chemical fiber industry, a certain flow of steam heating and heating is required for the stable operation of process production equipment. In addition, according to production needs, some functional areas in the plant need to be equipped with centralized air conditioning, and the air conditioning form of "cold and heat source + combined air conditioning unit" is required. Under winter air conditioning conditions, the heating section of the combined air conditioning unit generally uses low-pressure saturated steam.

[0003] In the above heat exchange processes, steam releases latent heat to generate steam condensate, which is a non-full-tube gas-liquid two-phase flow in the pipe, which is neither continuous nor stable. Although the temperature of steam condensate is as high as 90-100℃, it cannot be directly connected to the air conditioning hot water network or the factory heating network. If the waste heat and water volume of steam condensate are not recycled, it needs to be cooled to <35℃ before it can be discharged into the municipal sewage network, which not only wastes the heat energy of steam condensate, but also wastes the condensate volume, which is not conducive to the green and sustainable development of enterprises. Summary of the invention

[0004] To this end, the present invention provides a fan coil air conditioning water system whose heat source is steam condensate, so as to maximize the utilization of the waste heat of the steam condensate generated in the industrial plant, and solve the problem of low utilization rate of low-grade thermal energy of steam condensate in the industrial plant and waste of thermal energy.

[0005] In order to achieve the above-mentioned object, the present invention provides the following technical solutions: a fan coil air conditioning water system whose heat source is steam condensate, comprising a steam condensate subsystem, an air conditioning hot water subsystem, a steam subsystem, a water replenishment constant pressure device of the hot water subsystem, a PLC control subsystem and an air conditioning cold water subsystem;

[0006] The steam condensate subsystem is used to recover condensate from a combined air-conditioning unit in an industrial plant production device or an air-conditioning room whose heat source is low-pressure steam. The steam condensate subsystem includes an open condensate tank, a condensate pipeline, a condensate pump and a plant condensate tank;

[0007] The air conditioning hot water subsystem is used to provide a heat source for the air conditioning terminal under winter conditions, and the air conditioning hot water subsystem includes a hot water pipeline, a first filter, a hot water circulation pump, a water-to-water heat exchanger and a fan coil;

[0008] The steam subsystem is used to provide the heating load required by the air conditioning water system under winter conditions, and the steam subsystem includes a steam-water heat exchanger, a steam pipeline, a second filter, a steam electric regulating valve group and a steam trap group;

[0009] The water replenishment and pressure-regulating device of the hot water subsystem adopts a variable frequency automatic water replenishment pump to replenish water and maintain pressure, and the water replenishment and pressure-regulating device of the hot water subsystem uses the open condensation water tank of the steam condensation water subsystem as the water replenishment source;

[0010] The PLC control subsystem is used to provide control circuits and control implementation operation instructions for the air conditioning and hot water subsystem;

[0011] The air conditioning cold water subsystem is used to provide a cold source for the air conditioning terminal under summer working conditions. The air conditioning cold water subsystem includes a refrigerator, a cold water circulation pump group and a third filter.

[0012] As a preferred solution for the fan coil air conditioning water system with steam condensate as the heat source, the combined air conditioning units in the industrial plant production equipment and the air conditioning room use steam condensate generated after steam heating or tracing, which is transported through the condensate pipeline and centrally recovered to the open condensate tank;

[0013] The liquid level of the open condensing water tank is between the low level alarm and the high level alarm;

[0014] When the liquid level of the open condensing water tank reaches the high level alarm, the condensing water pump is interlocked and started, and the condensing water in the open condensing water tank is transported to the plant condensing water tank after the condensing water in the open condensing water tank absorbs heat through the water-to-water heat exchanger and is used to desalinate and recover the condensing water.

[0015] When the liquid level of the open condensing water tank reaches a low level alarm, the condensing water pump is interlocked and shut down, and the open condensing water tank starts to store water;

[0016] An overflow port is provided on the top side of the open condensing water tank. When the liquid level reaches the overflow port, the condensing water is discharged to the condensing water cooling pool through the overflow pipe.

[0017] A drain port is provided at the bottom of the open condensing water tank. When the open condensing water tank is inspected or cleaned, the drain valve is opened to drain the condensed water into the condensing water cooling pool;

[0018] A vent is provided on the top of the open condensation water tank; a heat-insulating material is provided on the outer surface of the open condensation water tank, the heat-insulating material is a rock wool board or an aluminum silicate board, and the outer protective layer of the heat-insulating material is an aluminum plate or a galvanized steel plate.

[0019] As a preferred solution for the fan coil air conditioning water system with steam condensate as the heat source, the capacity of the open condensate water tank is determined according to the hourly flow of condensate water in the plant area and the operation time of the fan coil air conditioning system; the condensate water pump stops running when and only when the condensate water pump is turned on for heat exchange during the fan coil operation time period and the fan coil air conditioning is turned off at night; the open condensate water tank contains the water storage capacity when the condensate water pump stops running at night;

[0020] The open condensing water tank is used for condensing water recovery and also serves as a water replenishment tank for the air-conditioning hot water subsystem; the capacity of the open condensing water tank is included in the expansion amount of the air-conditioning hot water subsystem;

[0021] The pump inlet of the condensate pump is connected to a reducing pipe, the pump outlet of the condensate pump is connected to a metal flexible connecting pipe, and a pressure gauge and a check valve are arranged at the rear section of the metal flexible connecting pipe at the pump outlet; a total of two condensate pumps are arranged, one for use and one for backup, and are switched by a first shut-off valve;

[0022] The flow rate of the condensate pump is the average hourly flow rate of the total amount of steam condensate recovered within 24 hours during daytime operation.

[0023] As the preferred solution for the fan coil air conditioning water system with steam condensate as the heat source, in winter heating conditions, the hot water return water from the fan coil in the air-conditioned room is first purified by the first filter, then the pressure is increased by the hot water circulation pump, and the heat of the condensed water from the open condensed water tank is absorbed in the water-to-water heat exchanger, and then flows through the steam-to-water heat exchanger;

[0024] The first filter is provided with a bypass pipeline, and a cut-off valve is used to realize switching; pressure gauges are respectively provided before and after the first filter to detect the pressure difference before and after the first filter;

[0025] A pressure gauge and a check valve are provided at the rear section of the metal flexible connecting pipe at the pump outlet of the hot water circulation pump; a total of two hot water circulation pumps are provided, one for use and one for backup, which are switched through a third shut-off valve; the bypass pipeline of the hot water circulation pump is used to absorb the water hammer impact that occurs when the pump is stopped, and a low-discharge valve is installed on the inlet pipeline of the hot water circulation pump;

[0026] The flow rate of the hot water circulation pump is the hot water flow rate of the fan coil air conditioner, which is determined according to the design heat load of the air-conditioned room.

[0027] As a preferred solution for a fan coil air conditioning water system whose heat source is steam condensate, the water-to-water heat exchanger is a plate heat exchanger, the primary side fluid is condensate from the open condensate water tank, and the secondary side fluid is return water from the fan coil;

[0028] The water flow rate on the primary side of the water-to-water heat exchanger is determined according to the amount of condensed water that can be recycled in the plant area, and the hot water flow rate of the fan coil air conditioner on the secondary side is determined according to the designed heat load of the air-conditioned room.

[0029] As a preferred solution for a fan coil air-conditioning water system whose heat source is steam condensed water, if the temperature of the air-conditioning hot water after absorbing the heat of the steam condensed water in the steam subsystem reaches the rated water supply temperature of the fan coil after passing through the water-to-water heat exchanger, there is no need to supplement heat from the steam source and the steam-to-water heat exchanger will not operate; if the temperature of the air-conditioning hot water does not reach the rated water supply temperature of the fan coil after passing through the water-to-water heat exchanger, heat is supplemented by the steam source so that the air-conditioning hot water reaches the rated water supply temperature of the fan coil after being heated in the steam-to-water heat exchanger.

[0030] As a preferred solution for a fan coil air conditioning water system whose heat source is steam condensate, the steam source is low-pressure saturated steam or low-pressure superheated steam, the steam source is first purified by a second filter before entering the steam-water heat exchanger, the hot side outlet of the steam-water heat exchanger is the condensate of the steam source, which is discharged to the open condensate water tank after passing through a steam trap group;

[0031] The inlet fluid on the primary side of the steam-water heat exchanger is the steam source from the factory, and its enthalpy value is determined according to the steam pressure and temperature parameters provided by the factory; the inlet fluid on the secondary side is the fan coil return water after preliminary heating by the water-to-water heat exchanger; the outlet fluid on the primary side is the steam condensate after the steam releases the latent heat; the outlet temperature on the secondary side is the set value to ensure that the water supply temperature of the fan coil at the air-conditioning terminal is constant; the steam flow on the primary side of the steam-water heat exchanger is determined according to the heat balance between the primary and secondary sides; the water-to-water heat exchanger and the steam-to-water heat exchanger are connected in series in two stages to ensure the required design heat load demand of the air-conditioned room.

[0032] As a preferred solution for the fan coil air conditioning water system whose heat source is steam condensate, the water replenishment and constant pressure device of the hot water subsystem adopts a variable frequency automatic water replenishment pump to replenish water and maintain constant pressure, and the constant pressure water replenishment point is set on the pipeline at the inlet of the hot water circulation pump; a safety valve is set after the valve group of the water replenishment pump, and when the system is over-pressured, the safety valve opens and releases the pressure to the open condensate tank through the return pipe;

[0033] The pump inlet and outlet of the water supply pump are respectively connected to the reducer and the metal flexible connecting pipe. A pressure gauge and a check valve are set at the rear section of the metal flexible connecting pipe at the pump outlet. There are 2 water supply pumps in total, 1 in use and 1 as a backup, which are switched by the second shut-off valve.

[0034] As a preferred solution for the fan coil air conditioning water system whose heat source is steam condensate, the PLC control subsystem displays the high-level alarm and low-level alarm signals of the open condensate tank, and realizes the start and stop control of the condensate pump through the PLC control circuit;

[0035] The PLC control subsystem realizes variable frequency automatic water replenishment control and start / stop switching of the water replenishment pump through the PLC control circuit and the electric control box panel according to the pressure monitoring value after the water replenishment pump valve group; realizes the start / stop switching of the hot water circulation pump through the PLC control circuit and the electric control box panel;

[0036] The PLC control subsystem adjusts the opening of the steam electric regulating valve through the PLC control circuit according to the temperature monitoring value set at the outlet of the steam-water heat exchanger of the water supply pipe of the fan coil unit, thereby realizing the flow regulation of the steam source.

[0037] As a preferred solution for the fan coil air conditioning water system with steam condensate as the heat source, the air conditioning cold water subsystem, in the summer cooling condition, the rated supply and return water of the fan coil comes from the cold water return water of the fan coil in the air-conditioned room, which is first purified by the third filter, and then the pressure is increased by the cold water circulation pump group, and after cooling in the evaporator of the refrigerator, the air conditioning cold water reaches the rated water supply temperature of the fan coil;

[0038] During the winter heating condition, the water supply main condition switching valve and the return main condition switching valve of the air-conditioning cold water subsystem are both closed, and the water supply main condition switching valve and the return main condition switching valve on the air-conditioning hot water subsystem are both opened; during the summer cooling condition, the water supply main condition switching valve and the return main condition switching valve of the air-conditioning cold water subsystem are both opened, and the water supply main condition switching valve and the return main condition switching valve on the air-conditioning hot water subsystem are both closed.

[0039] The present invention has the following advantages: it is provided with a steam condensate subsystem, an air conditioning hot water subsystem, a steam subsystem, a water replenishment constant pressure device of the hot water subsystem, a PLC control subsystem and an air conditioning cold water subsystem; the steam condensate subsystem is used to recover the condensate of the combined air conditioning unit in the industrial plant production device or the air conditioning room whose heat source is low-pressure steam, and the steam condensate subsystem includes an open condensate tank, a condensate pipe, a condensate pump and a plant condensate tank; the air conditioning hot water subsystem is used to provide a heat source for the air conditioning terminal under winter working conditions, and the air conditioning hot water subsystem includes a hot water pipe, a first filter, a hot water circulation pump, a water-to-water heat exchanger and a fan coil; the steam The subsystem is used to provide the heating load required by the air-conditioning water system under winter conditions. The steam subsystem includes a steam-water heat exchanger, a steam pipeline, a second filter, a steam electric regulating valve group and a steam trap group; the water replenishment and constant pressure device of the hot water subsystem adopts a variable frequency automatic water replenishment pump to replenish water and maintain pressure, and the water replenishment and constant pressure device of the hot water subsystem uses the steam condensate water subsystem as the water replenishment source; the PLC control subsystem is used to provide control circuits and control implementation operation instructions for the air-conditioning hot water subsystem; the air-conditioning cold water subsystem is used to provide a cold source for the air-conditioning terminal under summer conditions, and the air-conditioning cold water subsystem includes a refrigerator, a cold water circulation pump group, a third filter and an operating condition switching valve. The present invention avoids the drawbacks of direct discharge of steam condensate in industrial plants, saves energy and reduces emissions to a great extent, greatly improves the utilization rate of low-grade thermal energy of steam condensate in industrial plants, and has a significant effect of energy saving and efficiency improvement; the open condensate water tank is used as a steam condensate storage tank and also as a make-up water tank for a constant-pressure make-up water device, which is more flexible; the air-conditioning hot water process is a closed circulation system, which runs stably and reliably, and opens up a new process for the recycling of condensate in industrial plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0041] Figure 1 Schematic diagram of a fan coil air conditioning water system in which the heat source provided in an embodiment of the present invention is steam condensate water.

[0042] In the figure, 1. open condensate tank; 2. condensate pipe; 3. condensate pump; 4. plant condensate tank; 5. hot water pipe; 6. first filter; 7. hot water circulation pump; 8. water-to-water heat exchanger; 9. fan coil; 10. steam-water heat exchanger; 11. steam pipe; 12. second filter; 13. steam electric regulating valve group; 14. steam trap group; 15. make-up pump; 16. refrigerator; 17. cold water circulation pump group; 18. third filter; 19. overflow port; 20. drain port; 21. vent. DETAILED DESCRIPTION

[0043] The following is a description of the implementation of the present invention by specific embodiments. People familiar with the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. 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.

[0044] See also Figure 1 The embodiment of the present invention provides a fan coil air conditioning water system whose heat source is steam condensate, including a steam condensate subsystem, an air conditioning hot water subsystem, a steam subsystem, a water replenishment constant pressure device of the hot water subsystem, a PLC control subsystem and an air conditioning cold water subsystem; the steam condensate subsystem is used to recover condensate of a combined air conditioning unit in an industrial plant production device or an air conditioning room whose heat source is low-pressure steam, and the steam condensate subsystem includes an open condensate water tank 1, a condensate water pipeline 2, a condensate water pump 3 and a plant condensate water tank 4; the air conditioning hot water subsystem is used to provide a heat source for the air conditioning terminal under winter conditions, and the air conditioning hot water subsystem includes a hot water pipeline 5, a first filter 6, a hot water circulation pump 7, a water-to-water heat exchanger 8 and a fan coil 9; The steam subsystem is used to provide the heating load required by the air-conditioning water system under winter conditions. The steam subsystem includes a steam-water heat exchanger 10, a steam pipe 11, a second filter 12, a steam electric regulating valve group 13 and a steam trap group 14; The water replenishment and constant pressure device of the hot water subsystem adopts a variable frequency automatic water replenishment pump 15 to replenish water and maintain pressure, and the water replenishment and constant pressure device of the hot water subsystem uses the open condensing water tank 1 of the steam condensing water subsystem as the water replenishment source; The PLC control subsystem is used to provide control circuits and control implementation operation instructions for the air-conditioning hot water subsystem; The air-conditioning cold water subsystem is used to provide a cold source for the air-conditioning terminal under summer conditions, and the air-conditioning cold water subsystem includes a refrigerator 16, a cold water circulation pump group 17 and a third filter 18.

[0045] In this embodiment, the industrial plant production equipment and the combined air-conditioning unit in the air-conditioning room, in the industrial plant production equipment, the steam volume using steam heating and steam tracing is 2.5t / h, and the steam condensate flow rate generated by the combined air-conditioning unit in the air-conditioning room after steam heating is 3.5t / h, which is transported through the condensate pipe 2 and concentratedly recovered to the open condensate tank 1.

[0046] Among them, the liquid level of the open condensing water tank 1 is between the low alarm and the high alarm; when the liquid level of the open condensing water tank 1 reaches the high alarm, the interlocking condensing water pump 3 is started, and the condensed water in the open condensing water tank 1 is transported to the plant condensing water tank 4 after being returned to the fan coil 9 through the water-to-water heat exchanger 8 to absorb heat, and is used to desalt the water and recover the condensed water; when the liquid level of the open condensing water tank 1 reaches the low alarm, the interlocking condensing water pump 3 is closed, and the open condensing water tank 1 starts to store water; an overflow port 19 is provided on the top side of the open condensing water tank 1. When the liquid level reaches the overflow port 19, the condensed water is discharged from the overflow pipe to the condensing water cooling pool; a sewage outlet 20 is provided at the bottom of the open condensing water tank 1. When the open condensing water tank 1 is inspected or cleaned, the sewage valve is opened to discharge the condensed water to the condensing water cooling pool.

[0047] In this embodiment, the open condensing water tank 1 is provided with a vent hole 21 at the top, and is a normal pressure water tank. The temperature of the steam condensed water from the production equipment in the industrial plant and the combined air conditioning unit in the air conditioning room is 90-100°C, so the outer surface of the open condensing water tank 1 is provided with insulation measures. The insulation material can be a common insulation material such as a rock wool board or an aluminum silicate board. The outer protective layer of the insulation material is usually an aluminum plate or a galvanized steel plate.

[0048] In this embodiment, the capacity of the open condensate water tank 1 is determined according to the hourly flow rate of condensate water in the factory area and the operating time of the fan coil 9 air conditioning system; assuming that the operating time of the fan coil 9 air conditioning in the office area is 8:00-22:00, and the fan coil 9 stops running from 22:00 in the evening to 8:00 in the morning, the condensate pump 3 stops running when and only when the condensate pump 3 is turned on for heat exchange during the operating time period of the fan coil 9, and the fan coil 9 air conditioning is turned off at night; therefore, the open condensate water tank 1 has a water storage function, and the open condensate water tank 1 can accommodate a water storage capacity of about 60t when the condensate pump 3 stops running at night.

[0049] In this embodiment, the open condensing water tank 1 is not only used for condensing water recovery, but also serves as a water replenishment tank for the air conditioning hot water subsystem; the capacity of the open condensing water tank 1 is included in the expansion of the air conditioning hot water subsystem; the effective volume of the open condensing water tank 1 is selected as V = 72m 3 .

[0050] Among them, the pump inlet of the condensate pump 3 is connected to the reducer, the pump outlet of the condensate pump 3 is connected to the metal flexible connecting pipe, and a pressure gauge and a check valve are arranged at the rear section of the metal flexible connecting pipe at the pump outlet; to ensure the safe and stable operation of the system, two condensate pumps 3 are arranged, one for use and one for backup, which are switched by the first shut-off valve; the flow rate of the condensate pump 3 is the average hourly flow rate of 8.4t / h of the total amount of steam condensate recovered within 24 hours a day during daytime operation.

[0051] In this embodiment, the air conditioning hot water subsystem provides a heat source for the air conditioning terminal in winter conditions. In winter heating conditions, the rated supply and return water temperature of the fan coil unit 9 is 50°C / 60°C. The hot water return pipe temperature from the fan coil unit 9 in the air-conditioned room is 50°C. It is first purified by the first filter 6, and then the pressure is increased by the hot water circulation pump 7. It absorbs the heat of the condensed water from the open condensing water tank 1 in the water-to-water heat exchanger 8, and then flows through the steam-to-water heat exchanger 10 to ensure that the air conditioning hot water reaches the rated water supply temperature of 60°C of the fan coil unit 9.

[0052] The first filter 6 of the air conditioning hot water subsystem is used to filter impurities such as metal debris and dirt in the air conditioning hot water subsystem. The first filter 6 is provided with a bypass pipeline, and a cut-off valve is used to achieve switching; pressure gauges are respectively provided before and after the first filter 6 to detect the pressure difference before and after the first filter 6.

[0053] Among them, the pressure gauge and check valve are set at the rear section of the metal flexible connecting pipe of the pump outlet of the hot water circulation pump 7 of the air conditioning hot water subsystem; there are two hot water circulation pumps 7, one for use and one for backup, which are switched through the third shut-off valve; in addition, the bypass pipeline of the hot water circulation pump 7 is used to absorb the water hammer impact when the pump is stopped, and a low-discharge valve is installed on the inlet pipeline of the hot water circulation pump 7 to protect the water pump. The flow rate of the hot water circulation pump 7 is the air conditioning hot water flow rate of the fan coil 9, which is determined according to the design heat load of the air-conditioned room. The design heat load of the air-conditioned room is 488kW, and the required air conditioning hot water flow rate of the fan coil 9 is 42.0t / h.

[0054] In this embodiment, the water-to-water heat exchanger 8 of the air-conditioning hot water subsystem is a plate heat exchanger, the primary side fluid is the condensed water from the open condensed water tank 1, and the secondary side fluid is the return water from the fan coil 9; the primary side water flow of the water-to-water heat exchanger 8 is determined according to the amount of condensed water that can be recycled in the plant, and the secondary side air-conditioning hot water flow of the fan coil 9 is determined according to the heat load of the air-conditioned room.

[0055] Specifically, the condensate inlet temperature t1' on the primary side of the water-to-water heat exchanger 8 is 95°C, and the condensate outlet temperature t1" on the primary side of the water-to-water heat exchanger 8 is 55°C; the return water inlet temperature t2' on the secondary side of the fan coil 9 of the water-to-water heat exchanger 8 is 50°C, and the hot water outlet temperature t2" on the secondary side is 58°C. The steam condensate flow rate on the primary side of the water-to-water heat exchanger 8 is the average hourly flow rate of the total amount of steam condensate recovered within 24 hours during the daytime operation, which is 8.4t / h, and the air conditioning water flow rate on the secondary side of the fan coil 9 is 42.0t / h. The heat exchange capacity of the water-to-water heat exchanger 8 is 390.4kW.

[0056] In this embodiment, if the air-conditioning hot water temperature of the steam subsystem reaches the rated water supply temperature of 60°C of the fan coil unit 9 after absorbing the heat of the steam condensed water after passing through the water-to-water heat exchanger 8, there is no need to supplement heat from the steam source, and the steam-to-water heat exchanger 10 does not operate; if the air-conditioning hot water temperature does not reach the rated water supply temperature of 60°C of the fan coil unit 9 after passing through the water-to-water heat exchanger 8, heat is supplemented by the steam source so that the air-conditioning hot water reaches the rated water supply temperature of 60°C of the fan coil unit 9 after being heated in the steam-to-water heat exchanger 10.

[0057] Among them, the steam source is low-pressure saturated steam or low-pressure superheated steam, and the steam temperature and pressure parameters provided by the plant are P=0.3MPa, T=144°C. The steam source first passes through the second filter 12 for impurity removal and purification before entering the steam-water heat exchanger 10. The hot side outlet of the steam-water heat exchanger 10 is the condensed water of the steam source, which is discharged to the open condensed water tank 1 after passing through the steam trap group.

[0058] Among them, the inlet fluid of the primary side of the steam-water heat exchanger 10 is the steam source from the factory area, and the steam source is low-pressure saturated steam with P1=0.3MPa, and the corresponding saturation temperature is T1=144℃. The inlet fluid of the secondary side of the steam-water heat exchanger 10 is the return water of the fan coil 9 after preliminary heating by the water-water heat exchanger 8, that is, T2'=t2"=58℃; the primary side outlet fluid is the steam condensed water after the steam releases the latent heat, and the temperature is T1"=95℃; the hot water outlet temperature of the secondary side of the steam-water heat exchanger 10 is set at T2"=60℃ to ensure the constant water supply temperature of the fan coil 9. The heat exchange capacity of the steam-water heat exchanger 10 is 97.6kW. By connecting the water-water heat exchanger 8 and the steam-water heat exchanger 10 in series, the design heat load required for the air-conditioned room is met.

[0059] In this embodiment, the water replenishment and constant pressure device of the hot water subsystem adopts variable frequency automatic water replenishment pump 15 to replenish water and constant pressure, and the constant pressure water replenishment point is set on the pipeline at the inlet of the hot water circulation pump 7; a safety valve is set after the valve group of the water replenishment pump 15, and when the system is overpressured, the safety valve opens and releases pressure to the open condensing water tank 1 through the return pipe. The pump inlet and outlet of the water replenishment pump 15 are respectively connected to the reducer and the metal flexible connecting pipe, and the rear section of the metal flexible connecting pipe at the pump outlet is provided with a pressure gauge and a check valve; a total of 2 water replenishment pumps 15 are set, 1 for use and 1 for standby, and switched through the second shut-off valve.

[0060] In this embodiment, the PLC control subsystem displays the high-level alarm and low-level alarm signals of the open condensing water tank 1, and realizes the start and stop control of the condensing water pump 3 through the PLC control circuit; the PLC control subsystem realizes the variable frequency automatic water replenishment control and start and stop switching of the water replenishment pump 15 through the PLC control circuit and the electrical control box panel according to the pressure monitoring value after the valve group of the water replenishment pump 15; the start and stop switching of the hot water circulation pump 7 is realized through the PLC control circuit and the electrical control box panel; the PLC control subsystem adjusts the opening of the steam electric regulating valve through the PLC control circuit according to the temperature monitoring value set at the outlet of the steam-water heat exchanger 10 of the water supply pipe of the fan coil 9, thereby realizing the flow regulation of the steam source.

[0061] In this embodiment, when the air-conditioning cold water subsystem is in cooling operation in summer, the rated supply and return water of the fan coil 9 comes from the cold water return water of the fan coil 9 in the air-conditioned room. The rated supply and return water temperature of the fan coil 9 is 7°C / 12°C. The temperature of the cold water return pipe from the fan coil 9 in the air-conditioned room is 12°C. It is first purified by the third filter 18, and then the pressure is increased by the cold water circulation pump group 17. After being cooled in the evaporator of the refrigerator 16, the air-conditioning cold water reaches the rated water supply temperature of 7°C of the fan coil 9.

[0062] Among them, for the determined air-conditioning area, the fan coil unit 9 air-conditioning water system adopts two pipes, and the cold water pipe for the summer cooling condition is shared with the hot water pipe for the winter heating condition. Therefore, it is necessary to realize the cross-connection of the heat source and the cold source on the water system main pipe of the air-conditioning area. In the winter heating condition, the water supply main pipe condition switching valve and the return water main pipe condition switching valve of the air-conditioning cold water subsystem are both closed, and the water supply main pipe condition switching valve and the return water main pipe condition switching valve on the air-conditioning hot water subsystem are both opened. In the summer cooling condition, the water supply main pipe condition switching valve and the return water main pipe condition switching valve of the air-conditioning cold water subsystem are both opened, and the water supply main pipe condition switching valve and the return water main pipe condition switching valve on the air-conditioning hot water subsystem are both closed.

[0063] In summary, the present invention is provided with a steam condensate subsystem, an air conditioning hot water subsystem, a steam subsystem, a water replenishment constant pressure device of the hot water subsystem, a PLC control subsystem and an air conditioning cold water subsystem; the steam condensate subsystem is used to recover the condensate of the combined air conditioning unit in the industrial plant production equipment or the air conditioning room whose heat source is low-pressure steam, and the steam condensate subsystem includes an open condensate tank 1, a condensate pipe 2, a condensate pump 3 and a plant condensate tank 4; the air conditioning hot water subsystem is used to provide a heat source for the air conditioning terminal under winter conditions, and the air conditioning hot water subsystem includes a hot water pipe 5, a first filter 6, a hot water circulation pump 7, a water-to-water heat exchanger 8 and a fan coil 9; the steam subsystem is used to provide To supply the heating load required by the air conditioning water system under winter conditions, the steam subsystem includes a steam-water heat exchanger 10, a steam pipe 11, a second filter 12, a steam electric regulating valve group 13 and a steam trap group 14; the water replenishment and constant pressure device of the hot water subsystem adopts a variable frequency automatic water replenishment pump 15 for water replenishment and constant pressure, and the water replenishment and constant pressure device of the hot water subsystem uses the steam condensate water subsystem as the water replenishment source; the PLC control subsystem is used to provide control circuits and control implementation operation instructions for the air conditioning hot water subsystem; the air conditioning cold water subsystem is used to provide a cold source for the air conditioning terminal under summer conditions, and the air conditioning cold water subsystem includes a refrigerator 16, a cold water circulation pump group 17, a third filter 18 and an operating condition switching valve. The present invention avoids the drawbacks of direct discharge of steam condensate in industrial plants, saves energy and reduces emissions to a great extent, greatly improves the utilization rate of low-grade thermal energy of steam condensate in industrial plants, and has a significant effect of energy saving and efficiency improvement; the open condensate water tank 1 is used as a steam condensate storage tank and also as a make-up water tank for a constant-pressure make-up water device, which is more flexible; the air-conditioning hot water process is a closed circulation system, which runs stably and reliably, and opens up a new process for recycling condensate in industrial plants.

[0064] Although the present invention has been described in detail above by general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A fan coil air conditioning water system whose heat source is steam condensate, characterized in that: Including steam condensing water subsystem, air conditioning hot water subsystem, steam subsystem, water replenishment and constant pressure device of hot water subsystem, PLC control subsystem and air conditioning cold water subsystem; The steam condensate subsystem is used to recover condensate from a combined air-conditioning unit in an industrial plant production device or an air-conditioning room whose heat source is low-pressure steam. The steam condensate subsystem comprises an open condensate tank (1), a condensate pipe (2), a condensate pump (3) and a plant condensate tank (4); The air conditioning hot water subsystem is used to provide a heat source for the air conditioning terminal under winter working conditions, and the air conditioning hot water subsystem comprises a hot water pipe (5), a first filter (6), a hot water circulation pump (7), a water-to-water heat exchanger (8) and a fan coil unit (9); The steam subsystem is used to provide the heating load required by the air conditioning water system under winter working conditions, and the steam subsystem includes a steam-water heat exchanger (10), a steam pipe (11), a second filter (12), a steam electric regulating valve group (13) and a steam trap group (14); The water supply and pressure constant device of the hot water subsystem adopts a variable frequency automatic water supply pump (15) to supply water and maintain pressure, and the water supply and pressure constant device of the hot water subsystem uses the open condensation water tank (1) of the steam condensation water subsystem as a water supply source; The PLC control subsystem is used to provide control circuits and control implementation operation instructions for the air conditioning and hot water subsystem; The air conditioning cold water subsystem is used to provide a cold source for the air conditioning terminal under summer working conditions. The air conditioning cold water subsystem includes a refrigerator (16), a cold water circulation pump group (17) and a third filter (18).

2. A fan coil air conditioning water system with steam condensate as heat source according to claim 1, characterized in that: The combined air-conditioning units in industrial plant production facilities and air-conditioning rooms use steam heating or tracing to generate steam condensate, which is transported through the condensate pipe (2) and collected and recovered in the open condensate tank (1); The liquid level of the open condensing water tank (1) is between the low level alarm and the high level alarm; When the liquid level of the open condensing water tank (1) reaches a high level alarm, the interlocked condensing water pump (3) is started, and the condensing water in the open condensing water tank (1) is transported to the plant condensing water tank (4) after the condensing water in the open condensing water tank (1) absorbs heat through the water-to-water heat exchanger (8) and the return water of the fan coil unit (9) absorbs heat, and is then used to desalinate and recover the condensing water. When the liquid level of the open condensing water tank (1) reaches a low level alarm, the condensing water pump (3) is interlocked and shut down, and the open condensing water tank (1) starts to store water; The top side of the open condensing water tank (1) is provided with an overflow port (19), and when the liquid level reaches the overflow port (19), the condensing water is discharged to the condensing water cooling pool through the overflow pipe; The open condensing water tank (1) is provided with a drain outlet (20) at the bottom. When the open condensing water tank (1) is inspected or cleaned, the drain valve is opened to drain the condensed water into the condensing water cooling pool. The top of the open condensation water tank (1) is provided with an air vent (21); the outer surface of the open condensation water tank (1) is provided with a thermal insulation material, the thermal insulation material is a rock wool board or an aluminum silicate board, and the outer protective layer of the thermal insulation material is an aluminum plate or a galvanized steel plate.

3. A fan coil air conditioning water system with steam condensate as heat source according to claim 2, characterized in that: The capacity of the open condensing water tank (1) is determined based on the hourly flow of condensing water in the plant area and the operating time of the fan coil unit (9) air conditioning system; the condensing water pump (3) is turned on for heat exchange only when the fan coil unit (9) is running during the operating time period, and the fan coil unit (9) air conditioning is turned off at night, and the condensing water pump (3) stops running; the open condensing water tank (1) contains a water storage capacity when the condensing water pump (3) stops running at night; The open condensing water tank (1) is used for condensing water recovery and also serves as a water supply tank for the air-conditioning hot water subsystem; the capacity of the open condensing water tank (1) is included in the expansion amount of the air-conditioning hot water subsystem; The pump inlet of the condensate pump (3) is connected to a reducing pipe, the pump outlet of the condensate pump (3) is connected to a metal flexible connecting pipe, and a pressure gauge and a check valve are provided at the rear section of the metal flexible connecting pipe at the pump outlet; a total of two condensate pumps (3) are provided, one for use and one for backup, and are switched via a first shut-off valve; The flow rate of the condensate pump (3) is the average hourly flow rate of the total amount of steam condensate recovered within 24 hours during daytime operation.

4. A fan coil air conditioning water system with steam condensate as heat source according to claim 3, characterized in that: During winter heating operation, the hot water return from the fan coil unit (9) in the air-conditioned room is first purified by the first filter (6), then the pressure is increased by the hot water circulation pump (7), and the heat of the condensed water from the open condensing water tank (1) is absorbed in the water-to-water heat exchanger (8), and then the water flows through the steam-to-water heat exchanger (10); The first filter (6) is provided with a bypass pipeline, and a cut-off valve is used to realize switching; pressure gauges are respectively provided before and after the first filter (6) for detecting the pressure difference before and after the first filter (6); A pressure gauge and a check valve are provided at the rear section of the metal flexible connecting pipe at the pump outlet of the hot water circulation pump (7); two hot water circulation pumps (7) are provided, one for use and one for backup, and are switched via a third shut-off valve; a bypass line of the hot water circulation pump (7) is used to absorb water hammer shocks that occur when the pump is stopped, and a low-discharge valve is installed on the inlet pipe of the hot water circulation pump (7); The flow rate of the hot water circulation pump (7) is the air-conditioning hot water flow rate of the fan coil unit (9), which is determined according to the design heat load of the air-conditioned room.

5. A fan coil air conditioning water system with steam condensate as heat source according to claim 4, characterized in that: The water-to-water heat exchanger (8) is a plate-type heat exchanger, the primary side fluid is the condensed water from the open condensed water tank (1), and the secondary side fluid is the return water from the fan coil unit (9); The water flow rate of the water-to-water heat exchanger (8) on the primary side is determined according to the amount of condensed water that can be recycled in the factory area, and the air-conditioning hot water flow rate of the fan coil unit (9) on the secondary side is determined according to the designed heat load of the air-conditioned room.

6. A fan coil air conditioning water system with steam condensate as heat source according to claim 5, characterized in that: If the air-conditioning hot water temperature of the steam subsystem reaches the rated water supply temperature of the fan coil unit (9) after absorbing the heat of the steam condensed water after passing through the water-water heat exchanger (8), the steam source does not need to be used to supplement the heat, and the steam-water heat exchanger (10) does not operate; if the air-conditioning hot water temperature does not reach the rated water supply temperature of the fan coil unit (9) after passing through the water-water heat exchanger (8), the steam source is used to supplement the heat so that the air-conditioning hot water reaches the rated water supply temperature of the fan coil unit (9) after being heated in the steam-water heat exchanger (10).

7. A fan coil air conditioning water system with steam condensate as heat source according to claim 6, characterized in that: The steam source is low-pressure saturated steam or low-pressure superheated steam. The steam source is first purified by a second filter (12) and then enters the steam-water heat exchanger (10). The hot side outlet of the steam-water heat exchanger (10) is condensed water of the steam source, which is discharged to the open condensate tank (1) after passing through a steam trap group. The inlet fluid of the steam-water heat exchanger (10) on the primary side is the steam source from the factory, and its enthalpy value is determined according to the steam pressure and temperature parameters provided by the factory; the inlet fluid on the secondary side is the return water of the fan coil (9) after the preliminary heating by the water-water heat exchanger (8); the outlet fluid on the primary side is the steam condensed water after the steam releases the latent heat; the outlet temperature on the secondary side is a set value to ensure that the water supply temperature of the fan coil at the air-conditioning terminal is constant; the steam flow rate on the primary side of the steam-water heat exchanger (10) is determined according to the heat balance between the primary and secondary sides; by connecting the water-water heat exchanger (8) and the steam-water heat exchanger (10) in series, the design heat load required by the air-conditioned room is guaranteed.

8. A fan coil air conditioning water system with steam condensate as heat source according to claim 7, characterized in that: The water supply and pressure constant device of the hot water subsystem adopts a variable frequency automatic water supply pump (15) to supply water and maintain constant pressure, and the constant pressure water supply point is set on the pipeline of the hot water circulation pump (7) inlet; a safety valve is set after the valve group of the water supply pump (15); when the system is over-pressured, the safety valve opens and releases pressure to the open condensing water tank (1) through the return pipe; The pump inlet and outlet of the water supply pump (15) are respectively connected to the reducer and the metal flexible connecting pipe, and a pressure gauge and a check valve are provided at the rear section of the metal flexible connecting pipe at the pump outlet; a total of two water supply pumps (15) are provided, one for use and one for backup, and are switched by a second shut-off valve.

9. A fan coil air conditioning water system with steam condensate as heat source according to claim 8, characterized in that: The PLC control subsystem displays high-level alarm and low-level alarm signals of the open condensate water tank (1), and realizes start and stop control of the condensate water pump (3) through the PLC control circuit; The PLC control subsystem realizes variable frequency automatic water replenishment control and start / stop switching of the water replenishment pump (15) through the PLC control circuit and the electric control box panel according to the pressure monitoring value after the water replenishment pump (15) valve group; realizes start / stop switching of the hot water circulation pump (7) through the PLC control circuit and the electric control box panel; The PLC control subsystem adjusts the opening of the steam electric regulating valve through the PLC control circuit according to the temperature monitoring value set at the outlet of the steam-water heat exchanger (10) of the water supply pipe of the fan coil unit (9), thereby realizing flow regulation of the steam source.

10. A fan coil air conditioning water system with steam condensate as heat source according to claim 9, characterized in that: When the air-conditioning cold water subsystem is in the cooling mode in summer, the rated supply and return water of the fan coil unit (9) comes from the cold water return water of the air-conditioning room fan coil unit (9), which is first purified by the third filter (18), and then increased in pressure by the cold water circulation pump unit (17). After being cooled in the evaporator of the refrigerator (16), the air-conditioning cold water reaches the rated supply water temperature of the fan coil unit (9); During the winter heating condition, the water supply main pipe condition switching valve and the return water main pipe condition switching valve of the air conditioning cold water subsystem are both closed, and the water supply main pipe condition switching valve and the return water main pipe condition switching valve on the air conditioning hot water subsystem are both opened; during the summer cooling condition, the water supply main pipe condition switching valve and the return water main pipe condition switching valve of the air conditioning cold water subsystem are both opened, and the water supply main pipe condition switching valve and the return water main pipe condition switching valve on the air conditioning hot water subsystem are both closed.

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