A defrosting system for an evaporator of a water-cooled air conditioner

Abstract

The present invention discloses a defrosting system for the evaporator of a water-cooled air conditioner. The water-cooled air conditioner includes a refrigerant circulation circuit composed of a compressor (1), a shell-and-tube water condenser (5), a dryer filter (8), an expansion valve (9), and a finned evaporator (11). The present invention includes an electric control box (7), a bypass solenoid valve (3), a high-pressure pressure switch (4), and a low-pressure pressure switch (15). The bypass solenoid valve (3) is connected in parallel with the compressor (1). The low-pressure pressure switch (15) is installed on the pipeline between the finned evaporator (11) and the compressor (1). The high-pressure pressure switch (4) is installed on the pipeline between the compressor (1) and the shell-and-tube water condenser (15). The high-pressure pressure switch (4) and the low-pressure pressure switch (15) are respectively electrically connected to the electric control box (7) for signal transmission. The electric control box (7) is electrically connected to the bypass solenoid valve (3) for control. The present invention can effectively control the frosting of the fins of the finned evaporator.

Description

Technical Field

[0001] The present invention relates to the field of water-cooled air conditioning systems, and more specifically, to a defrosting system for a water-cooled air conditioner evaporator. Background Art

[0002] When operating in a low-temperature environment, an industrial water-cooled cabinet air conditioner operates for refrigeration. The temperature of the fin-tube heat exchanger (evaporator) continuously drops below 0°C, and frost begins to form on the fins. Long-term operation causes the fins to accumulate thick frost, which affects the heat exchange effect. As a result, the refrigeration performance of the industrial water-cooled cabinet air conditioner unit decreases, leading to a low-pressure alarm and shutdown, affecting user use.

[0003] Currently, it is common to detect the temperature of the fin-tube heat exchanger (evaporator) through a temperature sensor. When the temperature is too low and frost forms on the fins, the unit needs to stop for defrosting. At this time, the air conditioning system starts and stops repeatedly, resulting in a long defrosting cycle, unsatisfactory defrosting effect, and easy icing of the fins. Summary of the Invention

[0004] The purpose of the present invention is to provide a defrosting system for a water-cooled air conditioner evaporator to solve the problem of unsatisfactory defrosting effect in the existing air conditioning system defrosting.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A defrosting system for a water-cooled air conditioner evaporator, the water-cooled air conditioner includes a refrigerant circulation circuit formed by connecting a compressor (1), a shell-and-tube water condenser (5), a dryer filter (8), an expansion valve (9), and a finned evaporator (11) through pipelines, and includes an electric control box (7), a bypass solenoid valve (3), a high-pressure pressure switch (4), and a low-pressure pressure switch (15). The bypass solenoid valve (3) is bypass-connected between the inlet and outlet ends of the compressor (1), so that the bypass solenoid valve (3) is connected in parallel with the compressor (1). The low-pressure pressure switch (15) is installed on the pipeline between the finned evaporator (11) and the compressor (1). The high-pressure pressure switch (4) is installed on the pipeline between the compressor (1) and the shell-and-tube water condenser (15). The high-pressure pressure switch (4) and the low-pressure pressure switch (15) are respectively electrically connected to the electric control box (7) for signal transmission. The electric control box (7) is electrically connected to the bypass solenoid valve (3) for control. The electric control box (7) controls the on-off of the bypass solenoid valve (3) based on the signals collected by the high-pressure pressure switch (4) and the low-pressure pressure switch (15) to achieve defrosting.

[0007] Furthermore, the finned evaporator (11) is equipped with a circulation fan (12), and the electric control box (7) is also electrically connected to the compressor (1) and the circulation fan (12) for control.

[0008] Further, an exhaust temperature sensor (2) is installed at the outlet end of the compressor (1). The exhaust temperature sensor (2) is electrically connected to the electric control box (7) for signal transmission. The electric control box (7) controls the compressor (1) based on the signals collected by the exhaust temperature sensor (2) and the high-pressure pressure switch (4).

[0009] Further, an air outlet temperature sensor (13) is installed on the air outlet side of the circulation fan (12). The air outlet temperature sensor (13) is electrically connected to the electric control box (7) for signal transmission. The electric control box (7) controls the compressor (1) based on the signal collected by the air outlet temperature sensor (13).

[0010] Further, a cooling water temperature sensor (6) is installed at the water outlet of the shell-and-tube water condenser (5), and a freezing point pressure controller (14) is installed on the pipeline between the finned evaporator (11) and the compressor (1). The cooling water temperature sensor (6) and the freezing point pressure controller (14) are respectively electrically connected to the electric control box (7) for signal transmission. The electric control box (7) controls the compressor (1) and the circulation fan (12) based on the signals collected by the air outlet temperature sensor (13), the cooling water temperature sensor (6), and the freezing point pressure controller (14).

[0011] By controlling the frosting pressure and frosting time of the finned evaporator, and adopting the hot gas bypass method to control the bypass solenoid valve, the industrial water-cooled cabinet air conditioner does not stop running, heats and defrosts the finned evaporator. By adjusting the defrosting evaporation pressure and time, the frosting of the fins of the finned evaporator can be effectively controlled, enabling the industrial water-cooled cabinet air conditioner to operate in refrigeration in a low-temperature environment, with better defrosting effect and improved refrigeration performance of the industrial water-cooled cabinet air conditioner unit.

[0012] The beneficial effects of the present invention are as follows:

[0013] 1. The present invention provides a defrosting system for the evaporator of a water-cooled air conditioner. When the unit operates in the refrigeration condition in a low-temperature environment, this device can effectively avoid the problem of frosting on the fins of the evaporator of the unit.

[0014] 2. When the system of the present invention operates in the refrigeration condition in a low-temperature environment, it can avoid the problem of repeated start-stop of general industrial water-cooled cabinet air conditioners, extend the service life of the compressor and the unit, and make the unit more reliable.

[0015] 3. General industrial water-cooled cabinet air conditioners are always in repeated switching between the defrosting and refrigeration modes due to frosting on the fins of the evaporator, which affects the performance of the unit. This device effectively improves the problems of long frosting time and ice formation on the fins of the evaporator during the operation of the unit through control devices such as a freezing point protector, and improves the refrigeration performance of the industrial water-cooled cabinet air conditioner unit at low temperatures. Description of the Drawings

[0016] Figure 1 This is the schematic diagram of the system structure of the present invention. Detailed implementation manners

[0017] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0018] As Figure 1 shown, a defrosting system for an evaporator of a water-cooled air conditioner according to the present invention is used for an air-conditioning refrigerant circulation loop composed of a scroll compressor 1 (MC), a shell-and-tube water condenser 5 (KG-10), a drying filter 8 (DCL084S), an expansion valve 9 (TEX2), and a finned evaporator 11 (evaporator assembly) configured with a circulation fan 12 (MF). The present invention includes an electric control box 7 (KZX), an exhaust temperature sensor 2 (PT-100), a bypass solenoid valve 3 (EVR3), a high-pressure pressure switch 4 (YK-1.6 / 2.0), a cooling water temperature sensor 6 (PT-100), an air outlet temperature sensor 13 (PT-100), a freezing point pressure controller 145 (YK-0.35 / 0.4), and a low-pressure pressure switch 15 (YK-0.02 / 0.1).

[0019] In the air-conditioning refrigerant circulation loop, the first branch of the output end of the scroll compressor 1 is connected to the refrigerant input end of the shell-and-tube water condenser 5 through a φ12 copper pipe, and the second branch is connected to the input end of the bypass solenoid valve 3 through a φ9 copper pipe. The refrigerant output end of the shell-and-tube water condenser 5 is connected to the input end of the drying filter 8 through a pipe, the output end of the drying filter 8 is connected to the input end of the expansion valve 9 through a pipe, the output end of the expansion valve 9 is connected to the input end of a manifold 10 through a pipe, the output end of the manifold 10 is connected to the input end of the finned evaporator 11 through a pipe, and the output end of the finned evaporator 11 is connected to the input end of the scroll compressor 1 through a pipe.

[0020] An exhaust temperature sensor 2 and a high-pressure pressure switch 4 are installed on the output pipeline of the scroll compressor 1. When the exhaust temperature is higher than 110 °C, the scroll compressor 1 stops and reports a fault, and the fault is reset when the exhaust temperature is lower than 90 °C; when the condensation pressure is higher than 2.0 MPa, the scroll compressor 1 stops and reports a fault, and the fault is reset when the condensation pressure is lower than 1.6 MPa.

[0021] The circulation fan 12 is installed at the air outlet of the air conditioner. The finned evaporator 11 is installed at the air inlet, and the air outlet temperature sensor 13 is installed at the air outlet. Indoor air is cooled by the finned evaporator 11 and blown out by the circulation fan 12. The air outlet temperature sensor 13 detects the air outlet temperature T.

[0022] The shell-and-tube water condenser 5 has a water inlet and a water outlet. A cooling water temperature sensor 6 is installed at the water outlet. The cooling water exchanges heat with the refrigerant through the water inlet and the water outlet of the shell-and-tube water condenser 5, and the cooling water temperature sensor 6 detects the cooling water temperature.

[0023] The electric control box 7 is connected to the air outlet temperature sensor 13, the cooling water temperature sensor 6 (PT-100), and the freezing point pressure controller 14 through electric wires to detect the air outlet temperature, the cooling water temperature, and the evaporator freezing point defrosting signal. The electric control box 7 is connected to the scroll compressor 1 and the circulating fan 12 through a cable to control the start and stop of the scroll compressor 1 and the circulating fan 12.

[0024] A low-pressure pressure switch 15 and a freezing point pressure controller 14 are installed on the pipeline at the input end of the scroll compressor 1. The bypass solenoid valve 3 is bypass-connected between the input end and the output end of the scroll compressor 1, so that the bypass solenoid valve 3 is connected in parallel with the scroll compressor 1. When the evaporation pressure is lower than 0.05 MPa, the scroll compressor 1 stops running and reports a fault. When the evaporation pressure is higher than 0.1 MPa, the fault is reset. Refrigerant R22 is used in the refrigeration cycle loop. When the evaporation pressure is lower than 0.35 MPa, and the surface of the copper tube of the finned evaporator 11 is lower than -3 °C and lasts for 15 minutes, the freezing point pressure controller 14 gives an action signal to the electric control box 7, and the electric control box 7 outputs a voltage to make the bypass solenoid valve 3 conduct for 30 seconds, and the hot gas bypass of the air-conditioning refrigeration system defrosts and heats the evaporator.

[0025] The specific working process of the present invention is as follows:

[0026] When the device is working, after the unit is powered on, a startup instruction is given through the manual operation panel SP on the electric control box 7. First, set the outlet air temperature Te (25°C) according to the user's requirements and set various protection parameters such as current and exhaust temperature. After power-on, first start the circulation fan 12 to run at high speed. After a delay of 1 minute, detect the supply air temperature T. When the supply air temperature T is within the following range Te - ΔT ≤ T ≤ Te + ΔT, the system is in ventilation. When the supply air temperature T > Te + ΔT, start the scroll compressor 1, and the system enters the cooling and refrigeration mode and keeps the scroll compressor 1 working all the time. When it is detected that the supply air temperature T < Te - ΔT, the compressor 1 stops. When the ambient temperature is relatively low, the supply air temperature is relatively low. When the surface temperature of the evaporator copper tube and fin is lower than -3°C (the refrigeration system uses refrigerant R22 and the evaporation pressure is lower than 0.35 MPa), water vapor in the air will condense and frost on the surface of the evaporator, increasing the heat transfer air resistance, decreasing the evaporation pressure, and the freezing point pressure controller 14 (YK - 0.35 / 0.4) acts, sending a signal to the electric control board of the electric control box 7. After a delay of 15 minutes, the bypass solenoid valve 3 is turned on, and the high and low pressures of the air-conditioning refrigeration system are bypassed, increasing the evaporation pressure and the temperature of the finned evaporator 11. The finned evaporator 11 defrosts for 30 seconds, and then the bypass solenoid valve 3 is turned off, and the refrigeration cycle continues. This solves the problem that when operating in a low-temperature environment, the fins of the industrial water-cooled cabinet air conditioner frost thickly, affecting the heat transfer effect, reducing the refrigeration performance of the industrial water-cooled cabinet air conditioner unit, and causing a low-pressure alarm and shutdown.

[0027] The above embodiments are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements of the technical solutions of the present invention by those of ordinary skill in the art should fall within the protection scope determined by the claims of the present invention.

Claims

1. A defrosting system for an evaporator of a water-cooled air conditioner. The water-cooled air conditioner includes a refrigerant circulation circuit formed by connecting a compressor (1), a shell-and-tube water condenser (5), a dryer filter (8), an expansion valve (9), and a finned evaporator (11) through pipelines, and is characterized in that, It includes an electric control box (7), a bypass solenoid valve (3), a high-pressure pressure switch (4), and a low-pressure pressure switch (15). The bypass solenoid valve (3) is bypass-connected between the inlet and outlet ends of the compressor (1), so that the bypass solenoid valve (3) is connected in parallel with the compressor (1). The low-pressure pressure switch (15) is installed on the pipeline between the finned evaporator (11) and the compressor (1). The high-pressure pressure switch (4) is installed on the pipeline between the compressor (1) and the shell-and-tube water condenser (5). The high-pressure pressure switch (4) and the low-pressure pressure switch (15) are respectively electrically connected to the electric control box (7) for signal transmission. The electric control box (7) is electrically connected to the bypass solenoid valve (3) for control. The electric control box (7) controls the on-off of the bypass solenoid valve (3) based on the signals collected by the high-pressure pressure switch (4) and the low-pressure pressure switch (15) to achieve defrosting; The finned evaporator (11) is equipped with a circulation fan (12), and the electric control box (7) is also electrically connected to the compressor (1) and the circulation fan (12) respectively for control; An air outlet temperature sensor (13) is installed on the air outlet side of the circulation fan (12). The air outlet temperature sensor (13) is electrically connected to the electric control box (7) for signal transmission. The electric control box (7) controls the compressor (1) based on the signal collected by the air outlet temperature sensor (13); A cooling water temperature sensor (6) is installed at the water outlet of the shell-and-tube water condenser (5), and a freezing point pressure controller (14) is installed on the pipeline between the finned evaporator (11) and the compressor (1). The cooling water temperature sensor (6) and the freezing point pressure controller (14) are respectively electrically connected to the electric control box (7) for signal transmission. The electric control box (7) controls the compressor (1) and the circulation fan (12) based on the signals collected by the air outlet temperature sensor (13), the cooling water temperature sensor (6), and the freezing point pressure controller (14); An exhaust temperature sensor (2) is installed at the outlet end of the compressor (1). The exhaust temperature sensor (2) is electrically connected to the electric control box (7) for signal transmission. The electric control box (7) controls the compressor (1) based on the signals collected by the exhaust temperature sensor (2) and the high-pressure pressure switch (4).

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