[0031] Example one
[0032] Such as figure 1 As shown, the dual-temperature dual-compressor chiller of the present invention includes a unit casing 1 with an inner cavity. The unit casing 1 consists of a refrigeration casing 2 of a high-temperature shell-and-tube heat exchange device 11 and a low-temperature shell-and-tube heat exchange device The refrigeration shells 2 of 12 are connected to each other, and the outer side of the unit shell 1 is provided with an insulation layer 17. The unit shell 1 is provided with a high-temperature water return port 111, a medium-temperature water inlet and outlet 13 and a low-temperature water outlet 121 respectively. The nozzle 111 communicates with the high temperature shell and tube heat exchange device 11 in the unit shell 1, and the low temperature water outlet 121 communicates with the low temperature shell and tube heat exchange device 12 in the unit. The high temperature shell and tube heat exchange device 11 communicates with the low temperature The shell and tube heat exchange device 12 is provided with a switching structure that enables the high temperature shell and tube heat exchange device 11 to communicate with the low temperature shell and tube heat exchange device 12 and/or the medium temperature water inlet and outlet 13 respectively. The device 11 is in two-way communication with the high-temperature compression refrigeration circuit 14 located outside the unit shell 1, the low-temperature shell and tube heat exchange device 12 is in two-way communication with the low-temperature compression refrigeration circuit 15 located outside the unit casing 1, and the low-temperature compression refrigeration circuit 15 and the high-temperature compression The refrigeration circuits 14 are all connected to the control module 18, and the switching structure is connected to the control module 18. In the above solution, the control module 18 controls the high-temperature compression refrigeration circuit 14 and the low-temperature compression refrigeration circuit 15 to operate in conjunction to achieve dual-temperature water supply, and according to The actual load demand flexibly adjusts the water supply temperature, which overcomes the shortcomings of conventional chillers that cannot adapt to load changes, and thus operate under low load and low EER conditions for a long time.
[0033] Specifically, the switching structure includes a three-way switching valve 16 provided between the high-temperature shell and tube heat exchange device 11 and the low-temperature shell and tube heat exchange device 12 and having three connection interfaces. The three-way switching valve 16 is connected to the control module 18 , And the high temperature shell and tube heat exchange device 11 and the low temperature shell and tube heat exchange device 12 are respectively connected to two of the connection ports of the three-way switching valve 16, and the remaining one of the three-way switching valve 16 is connected to the medium temperature water inlet and outlet 13 In this solution, the control module 18 adjusts the ratio of the medium temperature water output to the low temperature water output by adjusting the three-way switch valve 16 according to the indoor high and low load requirements to effectively and quickly meet the load changes in the functional area.
[0034] More specifically, the cold water inlet 21 of the high temperature shell and tube heat exchange device 11 is a high temperature return water inlet 111, and the cold water outlet 22 of the high temperature shell and tube heat exchange device 11 is connected to a connection interface of the three-way switching valve 16. The refrigerant inlet 234 and refrigerant outlet 233 of the heat transfer tube bundle 23 in the high temperature shell and tube heat exchange device 11 are respectively connected to the high temperature compression refrigeration circuit 14, and the cold water inlet 21 of the low temperature shell and tube heat exchange device 12 is connected to the tee A connection interface of the switching valve 16 is connected, the cold water outlet 22 of the low temperature shell and tube heat exchange device 12 is a low temperature water outlet 121, and the refrigerant inlet 234 of the heat transfer tube bundle 23 in the low temperature shell and tube heat exchange device 12 is connected to The refrigerant outlet 233 communicates with the low-temperature compression refrigeration circuit 15 respectively.
[0035] In order to improve the heat exchange effect, the refrigerant in the high temperature shell and tube heat exchange device 11 and the low temperature shell and tube heat exchange device 12 in this embodiment adopts R123a, R404A, R410A or other refrigerants with good cooling effect and good heat exchange effect. Any one or a combination of more.
[0036] Similarly, in order to ensure the thermal insulation effect of the thermal insulation layer 17, the materials used for the thermal insulation layer 17 in this embodiment are ultrafine glass wool felt, flame-retardant polystyrene foam board, flame-retardant rigid polyurethane foam on site, and rubber-plastic thermal insulation. Any one or a combination of board or other effective insulation materials
[0037] Further, as figure 2 As shown, both the high temperature shell and tube heat exchange device 11 and the low temperature shell and tube heat exchange device 12 include a refrigeration housing 2 having a refrigeration cavity 25, and one end of the refrigeration housing 2 has a cold water inlet 21 communicating with the refrigeration cavity 25. The other end has a cold water outlet 22 communicating with the refrigeration cavity 25, a heat transfer tube bundle 23 for refrigerant to circulate in the refrigeration shell 2, and a refrigerant inlet 234 and a refrigerant outlet 233 at both ends of the heat transfer tube bundle 23, respectively Extending to the outside of the refrigeration shell 2, more specifically, the heat transfer tube bundle 23 is longitudinally bent and arranged between the cold water inlet 21 and the cold water outlet 22, which includes a plurality of longitudinally arranged between the cold water inlet 21 and the cold water outlet 22 The longitudinal extension portions 231 and the longitudinal extension portions 231 are all arranged parallel to each other, and two adjacent longitudinal extension portions 231 are connected by an arc-shaped curved portion 232, and the arc-shaped curved portion 232 extends to the cold water inlet 21 and the cold water outlet respectively twenty two.
[0038] In order to increase the contact area between the water source medium and the heat transfer tube bundle 23 and improve the heat exchange effect, the shell is also provided to divert the water source medium flowing in from the cold water inlet 21 so that the water source medium passes through the heat transfer tube bundle 23 multiple times. In order to fully contact the heat transfer tube bundle 23 and flow out from the cold water outlet 22 of the diversion structure 24, more specifically, the diversion structure 24 includes a number of horizontally arranged from top to bottom between two adjacent longitudinal extensions 231 The baffle 241, corresponding to the density of the baffle 241 provided between the two adjacent longitudinal extensions 231 of the cold water inlet 21 or the cold water outlet 22, is as high as the baffles provided on both sides of the refrigeration shell 2 The density of the plate 241 gradually becomes smaller. The baffles 241 of the guide structure 24 meet the purpose of sufficient heat exchange between the water source medium and the heat transfer tube bundle 23 and improve the heat exchange effect.
[0039] A refrigeration control method for a dual-temperature dual-compressor chiller, the method includes:
[0040] A. Dual temperature refrigeration: The switching structure is controlled by the control module 18 so that the high temperature shell and tube heat exchange device 11 is connected with the low temperature shell and tube heat exchange device 12 and the medium temperature water inlet and outlet 13 at the same time, and the chilled water sent back from the load side passes through the high temperature return port 111 enters the high-temperature shell-and-tube heat exchange device 11 and exchanges heat with the refrigerant in the high-temperature compression refrigeration circuit 14 to achieve cooling. Part of the chilled water after cooling enters the low-temperature shell-and-tube heat exchange device 12, and continues to communicate with The refrigerant in the low-temperature compression refrigeration circuit 15 performs heat exchange and further cools down, and is finally delivered from the low-temperature water outlet 121 to the terminal equipment. Another part of the chilled water is diverted through the switching structure and then directly delivered to the terminal equipment through the medium-temperature water inlet and outlet 13; this implementation For example, in this step, the control module 18 can adjust the ratio of the water entering the low-temperature shell and tube heat exchanger 12 and the medium-temperature water inlet and outlet 13 according to the load requirements by adjusting the three-way valve to meet various requirements during the dual-temperature cooling process. Required load demand.
[0041] B. Production of low-temperature chilled water: When the unit is under high load, the control module 18 controls the switching structure so that the high-temperature shell and tube heat exchange device 11 is only connected to the low-temperature shell and tube heat exchange device 12, and all chilled water flows through The high temperature shell and tube heat exchange device 11 and the low temperature shell and tube heat exchange device 12 respectively exchange heat with the refrigerant in the high temperature compression refrigeration circuit 14 and the refrigerant in the low temperature compression refrigeration circuit 15, and finally pass through the low temperature water outlet 121 It is delivered to the terminal equipment; in this embodiment, the standard refrigeration condition of the low-temperature compression refrigeration circuit 15 is 7/10°C of supply and return water, and in this step, the maximum amount of 7-10°C chilled water is produced.
[0042] C. High-temperature chilled water production: When the unit is under low load, the control module 18 controls the switching structure so that the high-temperature shell and tube heat exchanger 11 is only connected to the medium temperature water inlet and outlet 13, and the chilled water only flows through the high-temperature shell and tube The heating device 11 performs heat exchange with the refrigerant in the high-temperature compression refrigeration circuit 14, and is finally transported from the medium-temperature water inlet and outlet 13 to the terminal equipment; in this embodiment, the standard refrigeration working condition of the high-temperature compression refrigeration circuit 14 is 10/19 ℃, max. 10℃-19℃.
