Concentrated air-conditioning system capable of recycling condensate water and operation method of concentrated air-conditioning system

Abstract

The invention discloses a central air conditioning system capable of recycling condensate water and an operation method of the central air conditioning system. The central air conditioning system comprises a constant-pressure water replenishing unit, a cooling tower, a water chilling unit, a control system and a condensate water recycling unit, and the condensate water recycling unit comprises a heat exchanger and a condensate water tank; a water inlet of the condensate water tank is connected with a condensate water outlet of the air handling unit through a condensate water recovery pipeline; a water outlet of the condensate water tank enters the heat exchanger through a condensate water supply pipeline and then is divided into two paths, one path enters the soft water tank of the constant-pressure water supplementing unit, and the other path enters the cooling tower. The condensate water recycling unit is used for recycling condensate water generated in the operation process of the air handling unit, the cooling capacity of the condensate water is exchanged to cooling water, and primary utilization of the cooling capacity of the condensate water is achieved; condensate water subjected to heat exchange enters the cooling tower or the constant-pressure water supplementing unit, secondary utilization of the cooling capacity of the condensate water is achieved, the condensate water and the cooling capacity contained in the condensate water are recycled, and the operation energy efficiency of the water chilling unit is improved.

Description

Technical Field

[0001] The invention relates to an air conditioning system, and in particular to a centralized air conditioning system for recycling condensed water and an operating method thereof. Background Art

[0002] In summer, the central air conditioning system often uses fan coil units, ceiling air handling units, combined air handling units and other air handling units to treat the air during operation. These air handling units often produce condensed water with low temperature during operation. These condensed water is generally discharged nearby, resulting in waste. The design temperature of cold water supply and return water in the existing central air conditioning system is generally 7 / 12℃, and the design temperature of cooling water supply and return water is generally 32 / 37℃. However, due to factors such as expansion and leakage in the system, the cold water system and cooling water system of the central air conditioning system need to add a certain amount of water. Therefore, how to recycle and utilize condensed water in the central air conditioning system is crucial to reducing system energy consumption and reducing resource waste. Summary of the invention

[0003] In view of this, the present invention proposes a centralized air-conditioning system for recycling condensed water, and also proposes an operation method of the centralized air-conditioning system for recycling condensed water.

[0004] To achieve the above object, the present invention adopts the following technical solutions: The centralized air-conditioning system for recycling condensed water of the present invention comprises a constant-pressure water supply unit, a cooling tower, a chiller and a control system, and also comprises a condensed water recycling unit, wherein the condensed water recycling unit comprises a heat exchanger and a condensed water tank, wherein the water inlet of the condensed water tank is connected to the condensed water outlet of the air handling unit through a condensed water recovery pipeline; the water outlet of the condensed water tank enters the first channel of the heat exchanger through a condensed water supply pipeline, and the outlet of the first channel is divided into two paths, one path enters the soft water tank of the constant-pressure water supply unit through a first pipeline with a first electric valve, and the other path enters the cooling tower through a second pipeline with a second electric valve, and a condensed water pump group is arranged on the condensed water supply pipeline; The cooling tower, the second channel of the heat exchanger and the cooling water inlet of the chiller are connected through a cooling water supply pipeline; a cooling water circulation pump group is arranged on the cooling water supply pipeline between the heat exchanger and the chiller, and the outlet of the chiller is connected to the cooling tower through a cooling water return pipeline; a liquid level sensor is arranged in the condensed water tank, the signal output end of the liquid level sensor is connected to the signal output end of the control system, and the control output end of the control system is connected to the control input end of the condensed water pump group. The beneficial effect is that the present invention utilizes the condensed water recycling unit to recycle the condensed water generated during the operation of the air handling unit, exchanges the cooling capacity of the condensed water to the cooling water, and realizes the primary utilization of the cooling capacity of the condensed water; the temperature of the condensed water after heat exchange is lower than the temperature of the cooling water in the cooling tower, and can enter the cooling tower for use as cooling water, or the condensed water after heat exchange is replenished to the refrigeration cycle through the constant pressure water replenishment unit, so as to realize the secondary utilization of the cooling capacity of the condensed water, which not only recycles the condensed water and the cooling capacity contained therein, but also improves the operating energy efficiency of the chiller, reduces energy consumption, and realizes energy conservation and emission reduction.

[0005] Preferably, a refrigeration circulation loop is formed between the chiller and the air handling unit through a refrigeration water supply pipeline and a refrigeration water return pipeline, and a refrigeration circulation pump group is arranged on the refrigeration water return pipeline; The constant pressure water supply unit includes a high-level expansion water tank, a softened water treatment device and a soft water tank connected in sequence through pipelines, the soft water tank is connected to the refrigeration return water pipeline through a water supply pipeline, a water supply pump group is arranged on the water supply pipeline, and the high-level expansion water tank is connected to the refrigeration return water pipeline; The high-position expansion water tank, the soft water tank and the condensed water tank are all provided with grounded overflow pipelines.

[0006] Preferably, the refrigeration circulation pump group, water supply pump group, condensing water pump group and cooling water circulation pump group are all two or more groups. In the present invention, each pump group is at least two groups, which can be one standby and one in use, or two in use and one standby, to meet the normal operation requirements under different operating loads.

[0007] Preferably, there are at least two cooling towers connected in parallel, the cooling water return pipeline is connected to the water inlet at the top of each cooling tower, and the second pipeline is connected to the water inlet pipeline at the bottom of the cooling tower.

[0008] The present invention also provides an operation method of a centralized air-conditioning system for recycling condensed water, wherein the centralized air-conditioning system for recycling condensed water comprises a constant-pressure water supply unit, a cooling tower, a chiller and a control system, and further comprises a condensed water recycling unit, wherein the condensed water recycling unit comprises a heat exchanger and a condensed water tank, wherein the water inlet of the condensed water tank is connected to the condensed water outlet of the air handling unit through a condensed water recovery pipeline; the water outlet of the condensed water tank enters the first channel of the heat exchanger through a condensed water supply pipeline, the outlet of the first channel is divided into two paths, one path enters the soft water tank of the constant-pressure water supply unit through a first pipeline with a first electric valve, and the other path enters the cooling tower through a second pipeline with a second electric valve, and a condensed water pump group is arranged on the condensed water supply pipeline; The cooling tower, the second channel of the heat exchanger and the cooling water inlet of the chiller are connected through a cooling water supply pipeline; a cooling water circulation pump group is arranged on the cooling water supply pipeline between the heat exchanger and the chiller, and the outlet of the chiller is connected to the cooling tower through a cooling water return pipeline; A liquid level sensor is provided in the condensate water tank, a signal output end of the liquid level sensor is connected to a signal output end of the control system, and a control output end of the control system is connected to a control input end of the condensate pump group; The operation method comprises the following contents: starting the chiller and the air handling unit, and the condensed water generated by the air handling unit enters the condensed water tank through the condensed water recovery pipeline; when the liquid level in the condensed water tank rises to a preset height, starting the condensed water pump group, opening the second electric valve, and allowing the condensed water after heat exchange to enter the cooling tower; when the cooling tower is replenished with water, opening the first electric valve, and the condensed water enters the soft water tank through the condensed water supply pipeline, the heat exchanger and the first pipeline; the cooling water in the cooling tower enters the chiller after passing through the heat exchanger, and then flows back to the cooling tower through the chiller and the cooling water return pipeline.

[0009] The water temperature in the condensate water tank is 18°C, which is heated to 28°C after heat exchange; the temperature of the cooling water coming out of the cooling tower is 32°C, which is cooled to 30°C after absorbing the cooling capacity of the condensate water.

[0010] Compared with the prior art, the advantages of the present invention are: the present invention utilizes a condensed water recovery and utilization unit to recover the condensed water generated during the operation of the air handling unit, and exchanges the coldness of the condensed water with cooling water, thereby realizing the primary utilization of the coldness of the condensed water; the temperature of the condensed water after heat exchange is lower than the temperature of the cooling water in the cooling tower and can enter the cooling tower for use as cooling water, or the condensed water after heat exchange is supplied to the refrigeration cycle loop through a constant pressure water replenishment unit, thereby realizing the secondary utilization of the coldness of the condensed water, which not only recycles the condensed water and the coldness it contains, but also improves the operating energy efficiency of the chiller, reduces energy consumption, and achieves energy conservation and emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the present invention.

[0012] Figure 2 It is an enlarged view of the condensed water recovery unit of the present invention. DETAILED DESCRIPTION

[0013] The following is a detailed description of an embodiment of the present invention in conjunction with the accompanying drawings. This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and a specific operation process are given, but the protection scope of the present invention is not limited to the following embodiment.

[0014] It should be noted that, in the description of the present invention, relational terms such as “first” and “second” are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0015] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected" and "connection" that may appear should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0016] like Figure 1-2 As shown, the present invention proposes a centralized air-conditioning system for recycling condensed water, comprising a constant pressure water supply unit C, a cooling tower E, a chiller A, an air handling unit, a control system and a condensed water recycling unit F, wherein the air handling unit comprises a ceiling-mounted air handling unit G1, a combined air handling unit G2 and a fan coil unit G3; the condensed water recycling unit F comprises a heat exchanger F1 and a condensed water tank F2, the condensed water generated by the air handling unit is connected to the condensed water tank F2 via a condensed water recovery pipeline F3, the water outlet at the lower part of the condensed water tank F2 enters the first channel of the heat exchanger F1 via a condensed water supply pipeline F4, the outlet of the first channel is divided into two paths, one path enters the soft water tank C4 of the constant pressure water supply unit C via a first pipeline F6 with a first electric valve F5, and the other path enters the cooling tower E via a second pipeline F8 with a second electric valve F7, and a condensed water pump group F9 is provided on the condensed water supply pipeline F4 to provide power for the condensed water; The water outlet at the bottom of the cooling tower E, the second channel of the heat exchanger F1 and the cooling water inlet of the chiller A are connected in sequence through the cooling water supply pipeline D1. The cooling water from the cooling tower E enters the chiller A through the heat exchanger F1. When passing through the heat exchanger F1, it absorbs the coldness of the condensed water, so that its temperature drops from 32°C to 30°C, thereby reducing the supply temperature of the cooling water and the operating energy consumption of the chiller A. A cooling water circulation pump group D2 is provided on the cooling water supply pipeline D1 between the heat exchanger F1 and the chiller A to provide power for the cooling water circulation. The cooling water outlet of chiller A is connected to cooling tower E through cooling water return pipe D3. After heat exchange with the refrigerant circulation loop of chiller A, the cooling water flows back to cooling tower E through cooling water return pipe D3 to realize the circulation of cooling water. Such a circulation can absorb the coldness of condensed water and provide low-temperature cooling water for chiller A, thereby reducing the energy consumption of chiller A. The chiller A and the air handling unit form a refrigeration circulation loop through the refrigeration water supply pipeline B1 and the refrigeration return pipeline B2. The refrigeration circulation pump group B3 is provided on the refrigeration return pipeline B2. The refrigeration circulation pump group B3 provides circulation power for the cold water. The circulation loop is used to cool the indoor air to meet the indoor refrigeration demand; The constant pressure water supply unit C includes a high-level expansion water tank C1, a softened water treatment device C2, and a soft water tank C4 which are sequentially connected through pipelines. The soft water tank C4 is connected to the refrigeration return water pipeline B2 through a water supply pipeline. A water supply pump group C5 is arranged on the water supply pipeline. The high-level expansion water tank C1 is connected to the refrigeration return water pipeline B2. A liquid level probe is arranged in the high-level expansion water tank C1, and a signal output end of the liquid level probe is connected to the control system. When the liquid level in the high-level expansion tank C1 is lower than the lower limit setting value, the water supply pump group C5 supplies water to the cold water return pipeline. When the liquid level in the high-level expansion tank reaches the upper limit setting value, the water supply pump group C5 is turned off and the water supply is stopped. A liquid level sensor is provided in the condensate water tank F2, and the signal output end of the liquid level sensor is connected to the signal output end of the control system, and the control output end of the control system is connected to the control input end of the condensate water pump group F9. When the liquid level in the condensate water tank F2 rises to a certain height, the condensate water pump group F9 starts, so that the condensate water enters the cooling tower E through the condensate water supply pipeline F4, the heat exchanger F1, and the second pipeline F8, or enters the soft water tank C4 through the condensate water supply pipeline F4, the heat exchanger F1, and the first pipeline F6, which can be used as make-up water. In actual operation, the condensate water is heated from 18°C ​​to 28°C after heat exchange, which is lower than the outlet water temperature of the cooling tower. The condensate water after heat exchange is preferentially used for cooling tower make-up water, reducing the operating energy consumption of the chiller; the condensate water after heat exchange can also be used as make-up water for the soft water tank, realizing the maximum utilization of the condensate water and its contained cold capacity, and improving the utilization rate.

[0017] The present invention utilizes the condensed water recovery and utilization unit F to recover the condensed water generated during the operation of the air handling unit, and exchanges the coldness of the condensed water with the cooling water, thereby realizing the primary utilization of the coldness of the condensed water; the condensed water after heat exchange enters the cooling tower E or the constant pressure water replenishment unit C, and the temperature of the condensed water after heat exchange is lower than the temperature of the cooling water in the cooling tower E, or the condensed water after heat exchange is supplied to the refrigeration cycle loop through the constant pressure water replenishment unit C, thereby realizing the secondary utilization of the coldness of the condensed water, which not only recycles the condensed water and the coldness contained in it, but also improves the operating energy efficiency of the chiller A, reduces its operating energy consumption, and realizes energy conservation and emission reduction.

[0018] In actual installation, high-level expansion water tank C1, soft water tank C4 and condensate water tank F2 are all equipped with grounded overflow pipes. When the liquid level is too high, it overflows to the ditch through the overflow pipe; refrigeration circulation pump group B3, condensate pump group F9, cooling water circulation pump group D2 and make-up water pump group C5 are two or more groups. One, two or three groups are opened according to the cooling capacity demand to meet the normal operation requirements under different operating loads; there are two cooling towers E and they are connected in parallel. The cooling water return pipes D3 and The water inlet at the top of each cooling tower E is connected. Since the temperature of the cooling water rises after absorbing the heat of the refrigerant at the cooling unit, it enters from the top of the cooling tower E for cooling; the second pipeline F8 is connected to the water inlet pipeline at the bottom of the cooling tower E. The temperature of the condensed water after heat exchange in the heat exchanger F1 is 28°C, which is still lower than the cooling water temperature after cooling in the cooling tower E. Therefore, the condensed water can directly enter the cooling tower E from the bottom of the cooling tower E and can be directly used as cooling water to absorb the refrigerant heat of the chiller A.

[0019] During actual installation, there are two or more groups of chillers A, each group of chillers A includes an evaporator and a condenser, the cooling water supply pipeline D1 is connected to the condenser water inlet of each chiller A, the cooling water return pipeline D3 is connected to the condenser water outlet of each chiller A, the cold water supply pipeline is connected to the evaporator water outlet of each chiller A, and the cold water return pipeline is connected to the evaporator water return of each chiller A.

[0020] During actual installation, the four ports of the heat exchanger F1 are respectively provided with the first valve group F1a, the second valve group F1b, the third valve group F1c and the fourth valve group F1d. The first valve group F1a and the second valve group F1b are in a normally open state, so that the cooling water supply pipeline D1 is in a passage state; when the condensate pump group F9 is started, the third valve group F1c and the fourth valve group F1d are opened at the same time, so that the condensate enters the cooling tower E or the soft water tank C4, so as to realize the utilization of the cooling capacity of the condensate.

[0021] The operating method of the centralized air conditioning system for recycling condensed water of the present invention comprises the following contents: Start the chiller A, air handling unit, cooling water circulation pump group D2 and refrigeration circulation pump group B3. The cooling water transfers the coldness to the cold water circulation loop through the refrigerant circulation loop of the chiller A. The cold water circulation loop is used to cool the air of the air handling unit to achieve indoor cooling. During the refrigeration process, the air handling unit will generate condensed water, which will enter the condensed water tank F2 through the condensed water recovery pipeline F3. When the liquid level of the condensed water tank F2 rises to a certain height, the condensed water pump group F9 and the third valve group F1c, the fourth valve group F1d, and the second electric valve F7 are started to allow the condensed water after heat exchange to enter the cooling tower E from the bottom of the cooling tower E and be used as cooling water replenishment; When the cooling tower is replenished with water, the second electric valve F7 is closed and the first electric valve F5 is started. Under the action of the condensate pump group F9, the condensate enters the soft water tank C4 after passing through the heat exchanger F1 and is used as cold water replenishment.

[0022] In actual operation, the water temperature in the condensate tank F2 is 18°C, which rises to 28°C after heat exchange and can enter the cooling tower E or the soft water tank C4; the temperature of the cooling water coming out of the cooling tower E is 32°C, and the temperature of the cooling water after absorbing the condensate cooling is 30°C. The effective volume of the condensate tank F2 can be determined according to the amount of condensate generated during the operation of the air handling equipment to ensure that the energy storage needs can be met.

[0023] Finally, it should be emphasized that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions recorded in the aforementioned embodiments without creative work, or replace some of the technical features therein with equivalents. Therefore, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A centralized air conditioning system for recycling condensed water, comprising a constant pressure water supply unit, a cooling tower, a chiller and a control system, characterized in that: It also includes a condensed water recycling unit, which includes a heat exchanger and a condensed water tank, and the water inlet of the condensed water tank is connected to the condensed water outlet of the air handling unit through a condensed water recovery pipeline; The water outlet of the condensed water tank enters the first channel of the heat exchanger through the condensed water supply pipeline. The outlet of the first channel is divided into two paths, one path enters the soft water tank of the constant pressure water supply unit through the first pipeline with a first electric valve, and the other path enters the cooling tower through the second pipeline with a second electric valve. A condensed water pump group is arranged on the condensed water supply pipeline; The cooling tower, the second channel of the heat exchanger and the cooling water inlet of the chiller are connected through a cooling water supply pipeline; a cooling water circulation pump group is arranged on the cooling water supply pipeline between the heat exchanger and the chiller, and the outlet of the chiller is connected to the cooling tower through a cooling water return pipeline; A liquid level sensor is arranged in the condensate water tank, a signal output end of the liquid level sensor is connected to a signal output end of the control system, and a control output end of the control system is connected to a control input end of the condensate pump group.

2. The centralized air conditioning system for recycling condensed water according to claim 1, characterized in that: A refrigeration circulation loop is formed between the chiller and the air handling unit through a refrigeration water supply pipeline and a refrigeration water return pipeline, and a refrigeration circulation pump group is arranged on the refrigeration water return pipeline; The constant pressure water supply unit includes a high-level expansion water tank, a softened water treatment device and a soft water tank connected in sequence through pipelines, the soft water tank is connected to the refrigeration return water pipeline through a water supply pipeline, a water supply pump group is arranged on the water supply pipeline, and the high-level expansion water tank is connected to the refrigeration return water pipeline; The high-position expansion water tank, the soft water tank and the condensed water tank are all provided with grounded overflow pipelines.

3. The centralized air conditioning system for recycling condensed water according to claim 2, characterized in that: The refrigeration circulation pump group, water supply pump group, condensing water pump group and cooling water circulation pump group are all two or more groups.

4. The centralized air conditioning system for recycling condensed water according to claim 1, characterized in that: There are at least two cooling towers connected in parallel, the cooling water return pipeline is connected to the water inlet at the top of each cooling tower, and the second pipeline is connected to the water inlet pipeline at the bottom of the cooling tower.

5. An operating method of a centralized air conditioning system for recycling condensed water as claimed in claim 1, characterized in that: The operation method includes the following contents: Start the chiller and air handling unit. The condensed water generated by the air handling unit enters the condensed water tank through the condensed water recovery pipeline. When the liquid level in the condensed water tank rises to the preset height, start the condensed water pump group and open the second electric valve to allow the condensed water after heat exchange to enter the cooling tower. When the cooling tower is replenished with water, open the first electric valve and the condensed water enters the soft water tank through the condensed water supply pipeline, the heat exchanger and the first pipeline. The cooling water in the cooling tower enters the chiller after the heat exchanger and then flows back to the cooling tower through the chiller and the cooling water return pipeline.

6. The method for operating a centralized air conditioning system for recycling condensed water according to claim 1, characterized in that: The water temperature in the condensate water tank is 18°C, which is heated to 28°C after heat exchange; the temperature of the cooling water coming out of the cooling tower is 32°C, which is cooled to 30°C after absorbing the cooling capacity of the condensate water.

Images