High-efficiency chiller cold storage system based on dual-temperature phase change and cold storage method thereof

Abstract

The present invention discloses a high-efficiency cold storage system for chillers based on dual-temperature phase change, comprising a dual-temperature phase change cold storage water tank, a chiller, a user group, and a controller; the dual-temperature phase change cold storage water tank comprises a high-temperature phase change chamber, a low-temperature phase change chamber, and a mixed flow chamber, a high-temperature phase change material is arranged in the high-temperature phase change chamber, and a low-temperature phase change material is arranged in the low-temperature phase change chamber. The present invention also provides a cold storage method for a high-efficiency cold storage system for chillers based on dual-temperature phase change, wherein the controller controls a delivery pump group, a first three-way valve, a second three-way valve, a third three-way valve, and a fourth three-way valve to realize switching of different operating modes of the cold storage system. The present invention utilizes the phase change energy storage technology of the controller phase change material, which has the advantages of high energy storage density and small temperature change during energy storage, and combines the phase change material with the refrigeration system, so that the chiller increases the working condition close to full load during operation, improves the system operation efficiency, and reduces the start and stop times of the unit, thereby reducing the loss to the chiller.

Description

Technical Field

[0001] The present invention relates to the technical field of phase change energy storage and chiller cooling system, in particular to a high-efficiency chiller cold storage system based on dual-temperature phase change and a cold storage method thereof. Background Art

[0002] In the design process of air conditioning water system, the phenomenon of partial load operation of chillers is very common. As long as the central air conditioning system with chiller configuration greater than the cooling demand, most of them are operated at partial load. On the one hand, the efficiency of chillers at partial load is lower than that at full load (or near full load), and on the other hand, it also causes relative (at 100%) loss of pump power. Therefore, partial load operation of chillers has become one of the main reasons for high energy consumption of central air conditioning.

[0003] Knowing that chillers are most efficient only when they are close to full load, we should try to avoid running chillers at partial load. To achieve efficient operation of chillers, the existing measures are usually: (1) when multiple units are operated together, determine the appropriate number of units in operation based on the air conditioning load (cooling load); (2) adjust the cooling demand by starting and stopping the units; (3) when the cooling demand is higher than the cooling capacity of the chiller, actively reduce the cooling load demand of some sites, such as reducing the amount of fresh air, stopping the dehumidification air cabinet in the warehouse, and reducing the cooling capacity for self-use.

[0004] When multiple units are operated together, if the number of units is small, the cooling system is still prone to partial load operation. Too many units will increase the control difficulty and operation and maintenance costs of the system. Although starting and stopping the chiller can adjust the cooling demand, it will increase the wear and tear of the unit and the operating energy consumption. Actively reducing the cooling load demand of some sites will affect the thermal and humid environment of the area. Summary of the invention

[0005] The phase change energy storage technology based on phase change materials in the present invention has the advantages of high energy storage density and small temperature change during the energy storage process. The phase change material is combined with the refrigeration system to provide a high-efficiency chiller cold storage system based on dual-temperature phase change and a cold storage method thereof, so that the chiller can increase the operating conditions close to full load during operation, improve the system operation efficiency, and at the same time reduce the number of starts and stops of the unit, thereby reducing the loss to the chiller.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] The high-efficiency chiller cold storage system based on dual-temperature phase change provided by the present invention comprises a dual-temperature phase change cold storage water tank, a chiller, a user group, and a controller;

[0008] The dual-temperature phase-change cold storage water tank includes a high-temperature phase-change chamber, a low-temperature phase-change chamber, and a mixed flow chamber. The high-temperature phase-change chamber and the low-temperature phase-change chamber are respectively arranged on both sides of the mixed flow chamber. A high-temperature phase-change material is arranged in the high-temperature phase-change chamber, and a low-temperature phase-change material is arranged in the low-temperature phase-change chamber. The high-temperature phase-change chamber is connected to a first cold water inlet and outlet pipe, and the low-temperature phase-change chamber is connected to a second cold water inlet and outlet pipe.

[0009] The first cold water inlet and outlet pipe, the chiller, and the second cold water inlet and outlet pipe are connected through a first pipeline, the first cold water inlet and outlet pipe, the user group, and the second cold water inlet and outlet pipe are connected through a second pipeline, the first pipeline and the second pipeline are both provided with a delivery pump group, and the first pipeline and the second pipeline are connected through a connecting pipe;

[0010] The first cold water inlet and outlet pipe and the second pipeline are connected through a first three-way valve, the first cold water inlet and outlet pipe, the first pipeline, and the connecting pipe are connected through a second three-way valve, the second pipeline and the connecting pipe are connected through a third three-way valve, the third three-way valve is located between the delivery and distribution pump group and the user group, and the first pipeline, the second pipeline, and the second cold water inlet and outlet pipe are connected through a fourth three-way valve;

[0011] The controller is connected to the delivery and distribution pump group, the first three-way valve, the second three-way valve, the third three-way valve, and the fourth three-way valve.

[0012] Furthermore, the high-temperature phase change chamber and the low-temperature phase change chamber both include a phase change zone and a water outlet zone, a porous partition is provided between the phase change zone and the water outlet zone, the water outlet zone of the high-temperature phase change chamber is connected to the first cold water inlet and outlet pipe, the water outlet zone of the low-temperature phase change chamber is connected to the second cold water inlet and outlet pipe, a plurality of high-temperature phase change units are provided in the phase change zone of the high-temperature phase change chamber, a plurality of low-temperature phase change units are provided in the phase change zone of the low-temperature phase change chamber, and the phase change temperature of the high-temperature phase change unit is greater than the phase change temperature of the low-temperature phase change unit.

[0013] Furthermore, the high-temperature phase change unit and the low-temperature phase change unit are both spherical, the high-temperature phase change unit encapsulates a high-temperature phase change material with a phase change temperature of 11-12°C, and the low-temperature phase change unit encapsulates a low-temperature phase change material with a phase change temperature of 7-8°C.

[0014] Furthermore, a plurality of spoilers are staggered in the mixed flow chamber, and chamber valves are provided at both ends of the mixed flow chamber, one of the chamber valves is connected to the phase change zone of the high-temperature phase change chamber, and the other chamber valve is connected to the phase change zone of the low-temperature phase change chamber.

[0015] Furthermore, the distribution pump group includes a first stop valve, a Y-shaped steam / water separator, a water pump, a check valve, and a second stop valve which are sequentially arranged along the water flow direction, and the controller connects the first stop valve, the water pump, and the second stop valve.

[0016] Furthermore, the first cold water inlet and outlet pipe is provided with a first temperature sensor, the second cold water inlet and outlet pipe is provided with a second temperature sensor, and the controller is connected to the first temperature sensor and the second temperature sensor.

[0017] Furthermore, the first pipeline is provided with a first flow sensor, the second pipeline is provided with a second flow sensor, and the controller is connected to the first flow sensor and the second flow sensor.

[0018] Furthermore, a water supply pipe is also provided on the first pipeline, the water supply pipe is connected to a water supply system, and the water supply pipe is located between the second three-way valve and the delivery pump group on the first pipeline.

[0019] The present invention provides a cold storage method for a high-efficiency chiller cold storage system based on dual-temperature phase change. The cold storage method is that a controller controls a delivery pump group, a first three-way valve, a second three-way valve, a third three-way valve, and a fourth three-way valve to realize switching of different operating modes of the cold storage system. The system operating modes include: a chiller-only cooling mode, a dual-temperature phase change cold storage water tank-only cooling mode, a dual-temperature phase change cold storage water tank-only cooling mode, and a dual-temperature phase change cold storage water tank cooling mode while the chiller is cooling.

[0020] Furthermore, in the separate cooling mode of the chiller: the controller controls the distribution pump group on the first pipeline to start, the distribution pump group on the second pipeline to close, and controls the second three-way valve, the third three-way valve and the fourth three-way valve to connect the connecting pipe to the first pipeline and the second pipeline, the chiller and the user group form a circulation loop, the chiller flows out chilled water, which is supplied to the user group through the fourth three-way valve, and the user group returns high-temperature water, which flows through the second three-way valve, flows through the distribution pump group on the first pipeline, flows through the chiller, and is cooled into chilled water;

[0021] Dual-temperature phase-change cold storage water tank separate cooling mode: the controller controls the distribution pump group on the second pipeline to start, and controls the first three-way valve, the third three-way valve and the fourth three-way valve to form a circulation loop between the dual-temperature phase-change cold storage water tank and the user group. The low-temperature chilled water stored in the dual-temperature phase-change cold storage water tank is supplied to the user group through the second cold water inlet and outlet pipe and the fourth three-way valve. The user group returns high-temperature water, which flows through the third three-way valve, passes through the distribution pump group on the second pipeline, and then flows into the high-temperature phase change chamber, the mixed flow chamber and the low-temperature phase change chamber in sequence.

[0022] Dual-temperature phase-change cold storage water tank separate cold storage mode: The controller controls the distribution pump group on the first pipeline to start, the distribution pump group on the second pipeline to close, and controls the first three-way valve, the second three-way valve and the fourth three-way valve to form a circulation loop for the chiller and the dual-temperature phase-change cold storage water tank. The non-low-temperature chilled water stored in the dual-temperature phase-change cold storage water tank passes through the first cold water inlet and outlet pipe, flows through the first three-way valve and the second three-way valve into the first pipeline, and after passing through the distribution pump group on the first pipeline, enters the chiller to be cooled into chilled water. The chilled water passes through the fourth three-way valve and the second cold water inlet and outlet pipe and flows into the low-temperature phase change chamber, the mixed flow chamber and the high-temperature phase change chamber in sequence to store cold.

[0023] The dual-temperature phase-change cold storage water tank stores cold water in the dual-temperature phase-change cold storage water tank mode while the chiller supplies cold water: on the basis of the dual-temperature phase-change cold storage water tank separate cold storage mode, the controller controls the second three-way valve, the third three-way valve, and the fourth three-way valve to merge the user group into the chiller and the dual-temperature phase-change cold storage water tank to form a circulation loop. The chilled water flows out of the chiller and is divided into two paths through the fourth three-way valve. One path passes through the second cold water inlet and outlet pipe, flows into the low-temperature phase change chamber, the mixed flow chamber and the high-temperature phase change chamber in turn and then returns. The other path is supplied to the user group through the second pipeline. The user group returns high-temperature water and returns through the third three-way valve and the connecting pipe. The two return water paths are combined at the second three-way valve, enter the chiller after passing through the distribution pump group on the first pipeline, and then are cooled into chilled water.

[0024] The present invention has the following advantages:

[0025] 1. Phase change materials can store not only sensible heat but also huge latent heat of phase change. They have high energy density and can effectively solve the mismatch between the supply and demand of cooling capacity of chillers in terms of time and usage intensity.

[0026] 2. Two phase change materials with different temperatures are combined with the refrigeration system, so that the chiller can operate at close to full load, improve the system operation efficiency, reduce the number of start and stop times of the chiller, reduce the loss of the chiller, and improve the system operation efficiency and stability;

[0027] 3. The cold storage system can switch the cold storage mode under different electricity prices of valley electricity and peak electricity, which can save operating costs while meeting the needs of user groups. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a diagram of a high-efficiency chiller cold storage system based on dual-temperature phase change cold storage.

[0029] Figure 2 This is the circuit diagram for the chiller operating in cooling mode alone.

[0030] Figure 3 This is the operating loop diagram of the dual-temperature phase-change cold storage water tank in single cold storage mode.

[0031] Figure 4 Operation loop diagram of dual-temperature phase change cold storage water tank in cold storage mode while supplying cooling to the chiller.

[0032] Figure 5 This is the operating loop diagram of the dual-temperature phase-change cold storage water tank in single cooling mode.

[0033] Figure 6 It is a schematic diagram of the structure of a dual-temperature phase-change cold storage water tank.

[0034] In the figure, 1-dual-temperature phase-change cold storage water tank, 101-high-temperature phase-change chamber, 1011-high-temperature phase-change unit, 102-low-temperature phase-change chamber, 1021-low-temperature phase-change unit, 103-mixed flow chamber, 1031-spoiler, 1032-chamber valve, 2-chiller, 3-user group, 4-controller, 5-first cold water inlet and outlet pipe, 6-second cold water inlet and outlet pipe, 7-first pipeline, 8-second pipeline, 9-connecting pipe, 10-first three-way valve, 11-second three-way valve, 12-third three-way valve, 13-fourth three-way valve, 14-first stop valve, 15-Y-shaped steam / water separator, 16-water pump, 17-check valve, 18-second stop valve, 19-first temperature sensor, 20-second temperature sensor, 21-first flow sensor, 22-second flow sensor, 23-pore partition, 24 water supply pipe. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0036] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. 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.

[0037] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0038] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0039] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the invention is usually placed when in use, or the positions or positional relationships commonly understood by those skilled in the art, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0040] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" 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 it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] refer to Figure 1-6 As shown, an embodiment of the present invention is as follows:

[0042] This embodiment takes the office building application scenario as an example, determines the user-side cooling load according to the specifications, and then determines the cooling capacity of the chiller, performs selection calculations on the chiller, and then determines the cooling capacity of the dual-temperature phase-change cold storage water tank based on the hourly coefficient, the cooling capacity of the unit, the hourly cooling consumption, etc., and finally determines the structural parameters of the dual-temperature phase-change cold storage water tank.

[0043] A high-efficiency chiller cold storage system based on dual-temperature phase change, comprising a dual-temperature phase change cold storage water tank 1, a chiller 2, a user group 3, and a controller 4;

[0044] The dual-temperature phase-change cold storage water tank 1 includes a high-temperature phase-change chamber 101, a low-temperature phase-change chamber 102, and a mixed flow chamber 103. The high-temperature phase-change chamber 101 and the low-temperature phase-change chamber 102 are respectively arranged on both sides of the mixed flow chamber 103. The high-temperature phase-change chamber 101 is provided with a high-temperature phase-change material, and the low-temperature phase-change chamber 102 is provided with a low-temperature phase-change material. The high-temperature phase-change chamber 101 is connected to a first cold water inlet and outlet pipe 5, and the low-temperature phase-change chamber 102 is connected to a second cold water inlet and outlet pipe 6;

[0045] The first cold water inlet and outlet pipe 5, the chiller 2, and the second cold water inlet and outlet pipe 6 are connected through a first pipeline 7, and the first cold water inlet and outlet pipe 5, the user group 3, and the second cold water inlet and outlet pipe 6 are connected through a second pipeline 8. The first pipeline 7 and the second pipeline 8 are both provided with a distribution pump group, and the first pipeline 7 and the second pipeline 8 are connected through a connecting pipe 9;

[0046] The first cold water inlet and outlet pipe 5 and the second pipeline 2 are connected through a first three-way valve 10, the first cold water inlet and outlet pipe 5, the first pipeline 7, and the connecting pipe 9 are connected through a second three-way valve 11, the second pipeline 8 and the connecting pipe 9 are connected through a third three-way valve 12, the third three-way valve 12 is located between the delivery and distribution pump group and the user group 3, and the first pipeline 7, the second pipeline 8, and the second cold water inlet and outlet pipe 6 are connected through a fourth three-way valve 13;

[0047] The controller 5 is connected to the delivery and distribution pump group, the first three-way valve 10 , the second three-way valve 11 , the third three-way valve 12 , and the fourth three-way valve 13 .

[0048] Specifically, the first three-way valve 10, the second three-way valve 11, the third three-way valve 12, and the fourth three-way valve 13 are all electromagnetic three-way valves. Among them, the first three-way valve 10 is located in the middle of the first cold water inlet and outlet pipe 5, and is used to control the opening and closing of the first cold water inlet and outlet pipe 5 and the opening and closing of the first cold water inlet and outlet 5 and the second pipeline 8; the third three-way valve 12 on the second pipeline 8 is located between the delivery pump group and the user group 3, and is used to control the opening and closing of the second pipeline 8 and the opening and closing of the connecting pipe 8 and the second pipeline 8; the controller 4 includes but is not limited to a computer or a single-chip microcomputer, which is connected to the temperature sensor, flow sensor, water pump, stop valve, and electromagnetic three-way valve through a signal transmission line.

[0049] Furthermore, the high-temperature phase change chamber 101 and the low-temperature phase change chamber 102 both include a phase change zone and a water outlet zone, a porous partition 23 is provided between the phase change zone and the water outlet zone, the water outlet zone of the high-temperature phase change chamber 101 is connected to the first cold water inlet and outlet pipe 5, and the water outlet zone of the low-temperature phase change chamber 102 is connected to the second cold water inlet and outlet pipe 6, a plurality of high-temperature phase change units 1011 are provided in the phase change zone of the high-temperature phase change chamber 101, and a plurality of low-temperature phase change units 1021 are provided in the phase change zone of the low-temperature phase change chamber 102, and the phase change temperature of the high-temperature phase change unit 1011 is greater than the phase change temperature of the low-temperature phase change unit 1021.

[0050] Specifically in this embodiment, the high-temperature phase change unit 1011 and the low-temperature phase change unit 1021 are both spherical. The high-temperature phase change unit 1011 encapsulates a high-temperature phase change material with a phase change temperature of 11-12°C, and the low-temperature phase change unit 1021 encapsulates a low-temperature phase change material with a phase change temperature of 7-8°C.

[0051] In addition to storing sensible heat, phase change materials can also store huge latent heat of phase change. They have a high energy density and can effectively solve the mismatch problem between energy supply and demand in terms of time and usage intensity. In addition, phase change materials can melt at the melting point temperature to store heat. Therefore, in this embodiment, the above two phase change materials with different temperatures are used as energy storage media, corresponding to the phase change temperature of about 7-8°C required on the supply side of the chiller and the phase change temperature of about 11-12°C required on the return side. The cold water supplied to the chiller through the dual-temperature phase change cold storage water tank is increased to a relatively constant temperature of 12°C, and the cold water supplied to the user side is reduced to a relatively constant temperature of 7°C, thereby increasing the operating conditions close to full load during stable operation of the system and reducing the number of starts and stops of the unit during low load.

[0052] A plurality of spoilers 1031 are staggered in the mixed flow chamber 103 , and chamber valves 1032 are provided at both ends of the mixed flow chamber 103 . One of the chamber valves 1032 is connected to the phase change zone of the high-temperature phase change chamber 101 , and the other chamber valve 1032 is connected to the phase change zone of the low-temperature phase change chamber 102 .

[0053] In the specific setting, the diameter of the high-temperature spherical phase change unit 1011 is larger than the pore diameter of the pore partition 23, and also larger than the channel diameter of the chamber valve 1032, so as to ensure that the high-temperature spherical phase change unit 1011 only flows in the phase change zone of the high-temperature phase change chamber 101; correspondingly, the diameter of the low-temperature spherical phase change unit 1021 is larger than the pore diameter of the pore partition 23, and also larger than the channel diameter of the chamber valve 1032, so as to ensure that the low-temperature spherical phase change unit 1021 only flows in the phase change zone of the low-temperature phase change chamber 102; one end of the spoiler 1031 is fixedly connected to the side wall of the mixed flow chamber, and the other end has a gap with the side wall of the mixed flow chamber, and the two adjacent flow detour plates are staggered so that the water flow can flow back in the mixed flow chamber to improve the mixing efficiency.

[0054] In this embodiment, the distribution pump group includes a first stop valve 14, a Y-shaped steam / water separator 15, a water pump 16, a check valve 17, and a second stop valve 18 arranged in sequence along the water flow direction, and the controller 4 connects the first stop valve 14, the water pump 16, and the second stop valve 18.

[0055] In this system, the switching of the cold storage mode is achieved by using a controller to control the opening and closing of a valve on the pipeline according to the water flow temperature information on the pipeline. Therefore, a first temperature sensor 19 is provided on the first cold water inlet and outlet pipe 5, and a second temperature sensor 20 is provided on the second cold water inlet and outlet pipe 6. The controller 4 is connected to the first temperature sensor 17 and the second temperature sensor 20.

[0056] Furthermore, a first flow sensor 21 is provided on the first pipeline 1 , a second flow sensor 22 is provided on the second pipeline 8 , and the controller 4 is connected to the first flow sensor 21 and the second flow sensor 22 .

[0057] To ensure that the detection data is more timely and accurate, in the specific settings, the first temperature sensor 19 is set in the phase change zone close to the high-temperature phase change chamber 101; the second temperature sensor 20 is set in the phase change zone close to the low-temperature phase change chamber 102; the first flow sensor 21 is located between the chiller 2 and the fourth three-way valve 13; the second flow sensor 22 is located between the user side 3 and the fourth three-way valve 13.

[0058] In this embodiment, a water replenishment pipe 24 is further provided on the first pipeline 7 , and the water replenishment pipe 24 is connected to a water replenishment system. The water replenishment pipe 24 is located between the second three-way valve 11 and the first stop valve 14 on the first pipeline 7 .

[0059] Specifically, in this system, the water replenishment system can adopt the water replenishment constant pressure method commonly used in the design of air-conditioning water systems to maintain the static water pressure during system operation and ensure the stable circulation of the water system, including full water at the highest point of the system, accommodating the expansion of system water, replenishing the system water pressure reduction, exhausting, and draining water.

[0060] On the basis of the above-mentioned cold storage system, the present embodiment provides a cold storage method for a high-efficiency chiller cold storage system based on dual-temperature phase change. The cold storage method is that the controller controls the distribution pump group, the first three-way valve, the second three-way valve, the third three-way valve, and the fourth three-way valve to realize the switching of different operating modes of the cold storage system. The system operating modes include: chiller independent cooling mode, dual-temperature phase change cold storage water tank independent cooling mode, dual-temperature phase change cold storage water tank independent cold storage mode, and chiller cooling and dual-temperature phase change cold storage water tank cold storage mode. The above four modes are switched by controlling the valve by controller 4.

[0061] Specifically, taking the office building application scenario as an example, the system operation control method within a day is as follows:

[0062] First, starting from 00:00, the dual-temperature phase-change cold storage water tank is stored with low-peak electricity at midnight. During this period, the cold storage system operates in the dual-temperature phase-change cold storage water tank separate cold storage mode, and the chiller runs at full load, so as to store the required cooling capacity during the day in the shortest time; the controller 4 finds that no one is using water according to the monitoring of the second flow sensor 22, and the dual-temperature phase-change cold storage water tank operates in the separate cold storage mode, such as Figure 3The controller 4 controls the first stop valve 14, the second stop valve 18 and the water pump 16 on the first pipeline 7 to open, the distribution pump group on the second pipeline 8 to close, and controls the first three-way valve 10, the second three-way valve 11 and the fourth three-way valve 13 to form a circulation loop between the chiller 2 and the dual-temperature phase-change cold storage water tank 1. The non-low-temperature (7°C) chilled water stored in the dual-temperature cold storage water tank passes through the first cold water inlet and outlet pipe 5, flows through the first three-way valve 10, the second three-way valve 11, and after passing through the water pump 13 on the first pipeline 7, flows through the chiller 2 to be cooled into chilled water. The chilled water passes through the fourth three-way valve 13 and flows into the low-temperature phase change chamber 102 of the dual-temperature phase change cold storage water tank through the second cold water inlet and outlet pipe 6, contacts the spherical low-temperature phase change unit 1021, causing the spherical low-temperature phase change unit 1021 to solidify and release heat, thereby accumulating cold energy; then passes through the mixed flow chamber 103 and the high-temperature phase change chamber 101, contacts the spherical high-temperature phase change unit 1011, causing the spherical high-temperature phase change unit to further solidify and release heat, thereby accumulating cold energy; and flows out from the first cold water inlet and outlet pipe 5. The first temperature sensor 19 monitors the return water temperature. If the return water temperature is lower than the set temperature of 11°C, the cold storage tank is basically full of cold water. The water pump 16 and the chiller 2 on the first pipeline 7 are turned off, and the system's independent cold storage mode ends.

[0063] If the user needs cold water during this period, the chiller will enter the dual-temperature phase change cold storage water tank cold storage mode while the chiller is supplying cold water. Figure 4 As shown, the controller 4 controls the second three-way valve, the third three-way valve, and the fourth three-way valve to merge the user group 3 into the chiller 2 and the dual-temperature phase-change cold storage water tank 1 to form a circulation loop. However, the water demand late at night is relatively small, and the dual-temperature phase-change cold water tank single cold storage mode is mainly used.

[0064] After the chiller runs at full load in the single cooling mode at night, the dual-temperature phase-change cooling water tank is almost full. From 6:00 to 8:00 in the morning, people start to move around in the office building. At this time, the water demand is relatively small. The system starts the dual-temperature phase-change cooling water tank single cooling mode. Figure 5As shown, the cooling capacity stored by the low-peak electricity price at night is used to meet the cold water demand of the user group. In this mode, the controller 4 controls the first stop valve, the second stop valve and the water pump on the second pipeline 8 to open, the distribution pump group on the first pipeline to close, and controls the first three-way valve 10, the third three-way valve 12 and the fourth three-way valve 13 to form a circulation loop with the dual-temperature phase-change cold storage water tank 1 and the user group 3. The low-temperature (7°C) chilled water stored in the cold storage water tank is supplied to the user group through the second cold water inlet and outlet pipe 6 and the fourth three-way valve 13. The user group returns high-temperature (12°C) water, flows through the third three-way valve 12, passes through the water pump 16 on the second pipeline 8, enters the high-temperature phase change chamber 101, contacts the spherical high-temperature phase change unit 1011, causes the high-temperature phase change unit 1011 to melt and absorb heat, and releases cold; then passes through the mixed flow chamber 103 and the low-temperature phase change chamber 102, contacts the low-temperature phase change unit 1021, causes the low-temperature phase change unit 1021 to melt and absorb heat, releases cold, and flows out from the second cold water inlet and outlet pipe 6. In this process, that is, in the dual-temperature phase-change cold storage water tank single cooling mode, the controller 4 controls the first stop valve 14 on the first pipeline 7 to close, the second three-way valve 11 and the third three-way valve 12 at both ends of the connecting pipe 9 to open, and connect the water replenishment system on the water replenishment pipe 24 to achieve system constant pressure water replenishment. The first temperature sensor 19 monitors the return water temperature at the first cold water inlet and outlet pipe 5. If the return water temperature is higher than the set temperature of 8°C, the cold capacity of the dual-temperature phase-change cold storage water tank 1 has been basically released. At this time, the cold load of the office building gradually increases, and the system enters the cold storage mode of the cold storage water tank while the chiller is supplying cold.

[0065] During the period from 8:00 to 10:00, the number of people in the office building increases, but the outdoor temperature has not risen. At this time, the cooling load of the office building gradually increases. The controller 4 monitors the second flow sensor 22. If the water demand of the user group is less than the rated water volume of the chiller, the chiller still runs at full load, and the system enters the dual-temperature phase change cold storage water tank cooling mode while the chiller supplies cooling. Figure 4As shown. On the basis of the independent cold storage mode of the dual-temperature phase-change cold storage water tank, the controller controls the second three-way valve 11, the third three-way valve 12, and the fourth three-way valve 13 to merge the user group into the chiller 2 and the dual-temperature phase-change cold storage water tank 1 to form a circulation loop. The chilled water flows out of the chiller and passes through the fourth three-way valve 13 and is divided into two paths. One path flows through the second cold water inlet and outlet pipe 6 and flows into the low-temperature phase change chamber 102, contacts the spherical low-temperature phase change unit 1021, and causes the low-temperature phase change unit 1021 to solidify and release heat, thereby accumulating cold capacity; and then passes through the mixed flow chamber 103 and the high-temperature phase change chamber 101, contacts the high-temperature phase change unit 1011, and causes the high-temperature phase change unit 1021 to solidify and release heat, thereby accumulating cold capacity. 11 further solidifies and releases heat to accumulate cold capacity; the other way is supplied to user group 3 through the second pipeline 8, and the user group returns high-temperature (12°C) water, and returns water through the third three-way valve 12 and the connecting pipe 9; the two return waters are combined at the second three-way valve 11, enter the chiller 2 after passing through the water pump 16 on the first pipeline 7 and then cooled into chilled water; in this process, the first temperature sensor 19 monitors the return water temperature of the first cold water inlet and outlet pipe 5. If the return water temperature is lower than the set temperature of 11°C, the cold capacity of the dual-temperature phase-change cold storage water tank 1 has been basically stored, and the controller 4 controls the valve group to close the dual-temperature phase-change cold storage water tank to store cold, and the system enters the chiller's separate cooling mode.

[0066] During the period from 10:00 to 17:00, there are many people in the office building, and the outdoor temperature is also at a high level during the day. The cooling load of the office building is large, and the cold storage system enters the chiller unit's single cooling mode. Figure 2 As shown. The controller 4 controls the first stop valve 14, the water pump 16, and the second stop valve 18 on the first pipeline 7 to open, and the distribution pump group on the second pipeline 8 to close, and controls the second three-way valve 11, the third three-way valve 12, and the fourth three-way valve 13 to make the connecting pipe 9 connect the first pipeline 7 and the second pipeline 8, and the chiller 2 and the user group 3 form a circulation loop. The chiller flows out chilled water and supplies it to the user group 3 through the fourth three-way valve 13. The user group 3 returns high-temperature (12°C) water, flows through the second three-way valve 11, and flows through the water pump 16 on the first pipeline 1 through the chiller 2 and then cools into chilled water.

[0067] During the period from 17:00 to 22:00, the number of people in the office building decreases and the outdoor temperature also drops. Then the dual-temperature phase-change cold storage water tank is activated to provide cooling separately. Figure 5 As shown, the system operation mode refers to the mode described above, and the dual-temperature phase-change cold storage water tank is also in the single cooling mode. In this case, it is also necessary to connect the water replenishment system on the water replenishment pipe 24 to achieve system constant pressure water replenishment. During the dual-temperature phase-change cold storage water tank single cooling mode, the cold storage water tank has basically released the cold capacity, but the user side still needs chilled water supply, indicating that the cooling load demand on that day is abnormal, and the system needs to enter the chiller single cooling mode again.

[0068] During the period from 22:00 to 0:00 the next day, when there are very few people in the office building, the outdoor temperature is also lower, and the office cooling load is very low, the system starts the dual-temperature phase-change cold storage water tank independent cooling mode, and the cold water is supplied by the cold storage water tank. This cycle repeats, and the entire chiller cold storage system can operate efficiently and stably.

[0069] This system uses two phase change materials with different temperatures. When there is no demand for cooling at night, the high-efficiency chiller cold storage system enters the cold storage water tank separate cold storage mode; when the cooling demand matches the full-load cooling supply of the chiller, the high-efficiency chiller cold storage system enters the chiller separate cooling supply mode; when the cooling demand is slightly lower than the full-load cooling supply of the chiller, the system enters the cold storage water tank cold storage mode while the chiller is supplying cooling, and stores the cold in the phase change material; when the cooling demand is much lower than the full-load cooling supply of the chiller, the system enters the cold storage water tank separate cooling mode, and then releases the cold to the user side, so that the chiller increases the operating conditions close to full load during operation, improves the system operation efficiency, and at the same time reduces the number of start-stop times of the unit, reducing the loss to the chiller; moreover, under each operating condition, only one set of water pumps in the pipeline is started, which can improve the system operation stability and cold storage efficiency.

[0070] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. High-efficiency chiller cold storage system based on dual-temperature phase change, characterized by: Including dual-temperature phase-change cold storage water tank, chiller, user group, controller; The dual-temperature phase-change cold storage water tank includes a high-temperature phase-change chamber, a low-temperature phase-change chamber, and a mixed-flow chamber. The high-temperature phase-change chamber and the low-temperature phase-change chamber are respectively arranged on both sides of the mixed-flow chamber. The high-temperature phase-change chamber is provided with a high-temperature phase-change material, and the low-temperature phase-change chamber is provided with a low-temperature phase-change material. The high-temperature phase-change chamber is connected to a first cold water inlet and outlet pipe, and the low-temperature phase-change chamber is connected to a second cold water inlet and outlet pipe; the first cold water inlet and outlet pipe, the chiller, and the second cold water inlet and outlet pipe are connected through a first pipeline, the first cold water inlet and outlet pipe, the user group, and the second cold water inlet and outlet pipe are connected through a second pipeline, and the first pipeline and the second pipeline are both provided with a distribution pump group, and the first pipeline and the second pipeline are connected through a connecting pipe; The first cold water inlet and outlet pipe and the second pipeline are connected through a first three-way valve, the first cold water inlet and outlet pipe, the first pipeline, and the connecting pipe are connected through a second three-way valve, the second pipeline and the connecting pipe are connected through a third three-way valve, the third three-way valve is located between the delivery and distribution pump group and the user group, and the first pipeline, the second pipeline, and the second cold water inlet and outlet pipe are connected through a fourth three-way valve; The controller is connected to the delivery pump group, the first three-way valve, the second three-way valve, the third three-way valve, and the fourth three-way valve; The high-temperature phase change chamber and the low-temperature phase change chamber both include a phase change zone and a water outlet zone, a porous partition is provided between the phase change zone and the water outlet zone, the water outlet zone of the high-temperature phase change chamber is connected to the first cold water inlet and outlet pipe, the water outlet zone of the low-temperature phase change chamber is connected to the second cold water inlet and outlet pipe, a plurality of high-temperature phase change units are provided in the phase change zone of the high-temperature phase change chamber, a plurality of low-temperature phase change units are provided in the phase change zone of the low-temperature phase change chamber, the phase change temperature of the high-temperature phase change unit is greater than the phase change temperature of the low-temperature phase change unit; a plurality of spoilers are alternately provided in the mixed flow chamber, chamber valves are provided at both ends of the mixed flow chamber, one of the chamber valves is connected to the phase change zone of the high-temperature phase change chamber, and the other of the chamber valves is connected to the phase change zone of the low-temperature phase change chamber.

2. The high-efficiency chiller cold storage system based on dual-temperature phase change according to claim 1 is characterized in that: The high-temperature phase change unit and the low-temperature phase change unit are both spherical. The high-temperature phase change unit encapsulates a high-temperature phase change material with a phase change temperature of 11-12°C, and the low-temperature phase change unit encapsulates a low-temperature phase change material with a phase change temperature of 7-8°C.

3. The high-efficiency chiller cold storage system based on dual-temperature phase change according to claim 1 is characterized in that: The delivery and distribution pump group includes a first stop valve, a Y-shaped steam / water separator, a water pump, a check valve, and a second stop valve which are sequentially arranged along the water flow direction, and the controller is connected to the first stop valve, the water pump, and the second stop valve.

4. The high-efficiency chiller cold storage system based on dual-temperature phase change according to claim 1 is characterized in that: The first cold water inlet and outlet pipe is provided with a first temperature sensor, the second cold water inlet and outlet pipe is provided with a second temperature sensor, and the controller is connected to the first temperature sensor and the second temperature sensor.

5. The high-efficiency chiller cold storage system based on dual-temperature phase change according to claim 1 is characterized in that: The first pipeline is provided with a first flow sensor, the second pipeline is provided with a second flow sensor, and the controller is connected to the first flow sensor and the second flow sensor.

6. The high-efficiency chiller cold storage system based on dual-temperature phase change according to claim 1 is characterized in that: The first pipeline is also provided with a water supply pipe, the water supply pipe is connected to a water supply system, and the water supply pipe is located between the second three-way valve and the delivery pump group on the first pipeline.

7. The cold storage method of the high-efficiency chiller cold storage system based on dual-temperature phase change according to any one of claims 1 to 6, characterized in that: The cold storage method is that the controller controls the distribution pump group, the first three-way valve, the second three-way valve, the third three-way valve, and the fourth three-way valve to realize the switching of different operation modes of the cold storage system. The system operation modes include: the cold water unit alone supplying cooling mode, the dual-temperature phase change cold storage water tank alone supplying cooling mode, the dual-temperature phase change cold storage water tank alone storing cooling mode, and the cold water unit supplies cooling while the dual-temperature phase change cold storage water tank stores cooling mode.

8. The cold storage method of the high-efficiency chiller cold storage system based on dual-temperature phase change according to claim 7, characterized in that: The chiller is in a separate cooling mode: the controller controls the delivery pump group on the first pipeline to start, the delivery pump group on the second pipeline to close, and controls the second three-way valve, the third three-way valve and the fourth three-way valve to connect the connecting pipe to the first pipeline and the second pipeline, so that the chiller and the user group form a circulation loop, the chiller flows out chilled water, which is supplied to the user group through the fourth three-way valve, and the user group returns high-temperature water, which flows through the second three-way valve, flows through the delivery pump group on the first pipeline, flows through the chiller, and is cooled into chilled water; Dual-temperature phase-change cold storage water tank separate cooling mode: the controller controls the distribution pump group on the second pipeline to start, and controls the first three-way valve, the third three-way valve and the fourth three-way valve to form a circulation loop between the dual-temperature phase-change cold storage water tank and the user group. The low-temperature chilled water stored in the dual-temperature phase-change cold storage water tank is supplied to the user group through the second cold water inlet and outlet pipe and the fourth three-way valve. The user group returns high-temperature water, which flows through the third three-way valve, passes through the distribution pump group on the second pipeline, and then flows into the high-temperature phase change chamber, the mixed flow chamber and the low-temperature phase change chamber in sequence. Dual-temperature phase-change cold storage water tank separate cold storage mode: The controller controls the distribution pump group on the first pipeline to start, the distribution pump group on the second pipeline to close, and controls the first three-way valve, the second three-way valve and the fourth three-way valve to form a circulation loop for the chiller and the dual-temperature phase-change cold storage water tank. The non-low-temperature chilled water stored in the dual-temperature phase-change cold storage water tank passes through the first cold water inlet and outlet pipe, flows through the first three-way valve and the second three-way valve into the first pipeline, and after passing through the distribution pump group on the first pipeline, enters the chiller to be cooled into chilled water. The chilled water passes through the fourth three-way valve and the second cold water inlet and outlet pipe and flows into the low-temperature phase change chamber, the mixed flow chamber and the high-temperature phase change chamber in sequence to store cold. The dual-temperature phase-change cold storage water tank stores cold water in the dual-temperature phase-change cold storage water tank mode while the chiller supplies cold water: on the basis of the dual-temperature phase-change cold storage water tank separate cold storage mode, the controller controls the second three-way valve, the third three-way valve, and the fourth three-way valve to merge the user group into the chiller and the dual-temperature phase-change cold storage water tank to form a circulation loop. The chilled water flows out of the chiller and is divided into two paths through the fourth three-way valve. One path passes through the second cold water inlet and outlet pipe, flows into the low-temperature phase change chamber, the mixed flow chamber and the high-temperature phase change chamber in turn and then returns. The other path is supplied to the user group through the second pipeline. The user group returns high-temperature water and returns through the third three-way valve and the connecting pipe. The two return water paths are combined at the second three-way valve, enter the chiller after passing through the distribution pump group on the first pipeline, and then are cooled into chilled water.

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