Return air reheating type fan coil

Abstract

The return air reheating type fan coil comprises a fan, a heat exchanger, a primary air return box, a secondary air return box, a fresh air opening, a primary air return opening, a secondary air return opening, a secondary air return pipe and an air supply opening, and is characterized in that the primary air return box is provided with the fresh air opening and the primary air return opening, and the secondary air return box is provided with the secondary air return opening, the secondary air return pipe and the air supply opening; the draught fan comprises a volute, a wind wheel and a motor, an air suction opening of the draught fan is communicated with the secondary air return box, an air outlet of the draught fan is connected with an air supply opening of the secondary air return box, a secondary air return pipe is installed in the secondary air return box, a lower air inlet is communicated with the secondary air return opening, and an upper air outlet is communicated with the secondary air return box. When the secondary air return box is operated in winter, indoor low-temperature air enters the secondary air return pipe to dissipate heat and cool the motor, the motor is prevented from being burnt down, and the service life of the motor is prolonged.

Description

Technical Field

[0001] The invention belongs to the field of ventilation and air conditioning, and in particular relates to a return air reheating type fan coil unit. Background Art

[0002] The Chinese patent "Temperature and humidity independently controlled fan coil unit" (application number 202411190091.x) discloses a return air reheat type fan coil unit, whose fan is placed at the front end of the heat exchanger. However, in winter, the air is heated by the heat exchanger and flows through the fan motor. The high temperature air is not conducive to the heat dissipation of the motor, which is prone to burning and affects the life of the motor. Summary of the invention

[0003] The object of the present invention is to provide a return air reheating type fan coil unit which prevents hot air heated by a heat exchanger from flowing through a fan motor in winter, thereby facilitating heat dissipation of the motor, preventing the motor from burning out, and increasing the life of the motor.

[0004] The solution of the present invention is: a return air reheat type fan coil unit, which includes a fan, a heat exchanger, a primary return air box, a secondary return air box, a fresh air inlet, a primary return air inlet, a secondary return air inlet, a secondary return air duct, and an air supply inlet. The characteristics are that the primary return air box has a fresh air inlet and a primary return air inlet, the secondary return air box has a fan, a secondary return air inlet, a secondary return air duct, and an air supply inlet, the primary return air box is connected to the air inlet of the heat exchanger, the air outlet of the heat exchanger is connected to the secondary return air box, the fan is installed in the secondary return air box, it includes a volute, a wind wheel, and a motor, and its suction air The air inlet is connected to the secondary return air box, the air outlet is connected to the air supply port of the secondary return air box, the secondary return air duct is installed in the secondary return air box, the lower air inlet is connected to the secondary return air inlet, the upper air outlet is connected to the secondary return air box, and is connected to the secondary return air box shell, the upper air outlet is higher than the fan motor, the fan motor is mounted therein, the air intake of the secondary return air inlet all flows through the fan motor, and then enters the secondary return air box, the fan is a variable speed fan, the fresh air inlet, primary return air inlet and secondary return air inlet are adjustable air inlets, and the heat exchanger is connected to the air-conditioning hot water or refrigerant.

[0005] During the cooling operation in summer, the fresh air inlet, primary return air inlet and secondary return air inlet are fully opened, the fan is started, and the refrigerant of the heat exchanger is connected. Under the suction of the fan, the indoor primary return air passes through the primary return air inlet and the outdoor fresh air enters the primary return air box through the fresh air inlet. After mixing, they are sent to the heat exchanger to cool and dehumidify the air to reach the dew point state, and then sent to the secondary return air box. Another part of the higher temperature return air in the room enters the secondary return air duct through the secondary return air inlet under the suction of the fan, flows through the fan motor and enters the secondary return air box, mixes with the low-temperature air processed by the heat exchanger, is reheated and heated to reach the designed supply air temperature, and is finally sent to the air-conditioned room through the supply air outlet by the fan.

[0006] When heating is in operation in winter, the fresh air inlet and the primary return air inlet are fully opened, the secondary return air inlet is slightly opened, the fan is started, and the heat medium of the heat exchanger is connected. Under the suction of the fan, the indoor primary return air passes through the primary return air inlet, and the outdoor fresh air passes through the fresh air inlet into the primary return air box, and is mixed and sent to the heat exchanger to heat the air, and then sent to the secondary return air box. Since the secondary return air inlet is slightly opened, a small amount of low-temperature return air in the room passes through the secondary return air inlet and enters the secondary return air duct under the suction of the fan, flows through the fan motor, cools the motor, and then enters the secondary return air box, mixes with the hot air processed by the heat exchanger, reaches the designed supply air temperature, and is finally sent to the air-conditioned room through the supply air inlet by the fan. Since a small amount of low-temperature return air in the room enters the secondary return air duct, it prevents the entry of high-temperature air, ensures the heat dissipation of the motor, and has little effect on the supply air temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 This is the structure diagram of the return air reheat fan coil unit Figure 2 yes Figure 1 AA profile Figure 1 Figure 3 yes Figure 1 AA profile Figure 2 Description of reference numerals: 1. Fresh air inlet, 2. Primary return air inlet, 3. Primary return air box, 4. Heat exchanger, 5. Secondary return air box, 6. Air supply plate, 7. Air supply outlet, 8. Secondary return air inlet, 9. Secondary return air duct, 10. Fan volute, 11. Fan motor, 12. Refrigerant pipe, 13. Duct notch, 14. Motor shaft, 15. Motor fixing bracket, 16. Filter, 17. Upper cover, 18. Ventilation hole. DETAILED DESCRIPTION

[0008] Figure 1 , 2In the invention, a return air reheat type fan coil unit is provided, which comprises a fan, a heat exchanger 4, a primary return air box 3, a secondary return air box 5, a fresh air inlet 1, a primary return air inlet 2, a secondary return air inlet 8, a secondary return air duct 9, and an air supply inlet 7. The characteristics of the fan coil unit are as follows: the primary return air box 3 is provided with a fresh air inlet 1, a primary return air inlet 2, the secondary return air box 5 is provided with a secondary return air inlet 8, a secondary return air duct 9, and an air supply inlet 7; the primary return air box 3 is connected to an air inlet of a heat exchanger 4, and an air outlet of the heat exchanger 4 is connected to the secondary return air box 5; the fan is installed in the secondary return air box 5, and comprises a fan volute 10, a fan impeller, and a fan motor 11; the air inlet of the fan coil unit is connected to the secondary return air box 5, and the air outlet of the fan coil unit is connected to the secondary return air box 5; The air supply port 7 of the secondary return air box 5 and the secondary return air duct 9 are installed in the secondary return air box 5, the lower air inlet is connected with the secondary return air port 8, the upper air outlet is connected with the secondary return air box 5 and is connected to the shell of the secondary return air box 5, the upper air outlet is higher than the fan motor 11, and the fan motor 11 is inserted therein, and the air intake of the secondary return air port 8 all flows through the fan motor 11, and then enters the secondary return air box 5, thereby ensuring that the fan motor 11 is fully cooled. The fan is a variable speed fan with three gears of speed adjustment, the fresh air port 1, the primary return air port 2, and the secondary return air port 8 are adjustable electric or manual air ports, and the heat exchanger 4 is connected to the air-conditioning hot and cold water or refrigerant. The secondary return air box 5 is provided with an air supply plate 6, on which an air supply port 7 is provided, connected to the fan outlet, and connected to the room air supply pipe. The figure shows a single motor with double volutes, and the fan motor 11 is a coaxial motor, fixed to the air supply plate 6 by a motor fixing bracket 15. It can also be in the form of a single motor with a single volute, a single motor with three volutes, etc. The secondary return air pipe 9 is provided with an air pipe notch 13. When installed, the air pipe notch 13 passes through the motor shaft 14 to fix the secondary return air pipe 9 on the air supply plate 6. Through calculation and actual operation of the adjustment of the fresh air outlet 1, the primary return air outlet 2, and the secondary return air outlet 8, the balance of the air volume of each air outlet is ensured and the air conditioning demand is met. The area of ​​the secondary return air outlet 8 is preferably between 20% and 50% of the sum of the areas of the fresh air outlet 1 and the primary return air outlet 2. A smaller area can be adjusted during winter operation. Filters are installed at the fresh air outlet 1, the primary return air outlet 2, and the secondary return air outlet 8.

[0009] During the cooling operation in summer, the fresh air inlet 1, the primary return air inlet 2 and the secondary return air inlet 8 are fully opened, the fan is started, and the refrigerant of the heat exchanger 4 is connected. Under the suction of the fan, the indoor primary return air passes through the primary return air inlet 2, and the outdoor fresh air enters the primary return air box 3 through the fresh air inlet 1. After mixing, they are sent to the heat exchanger 4 to cool and dehumidify the air to reach the dew point state, and then sent to the secondary return air box 5. Another part of the higher temperature return air in the room enters the secondary return air duct 9 through the secondary return air inlet 8 under the suction of the fan, flows through the fan motor 11 and enters the secondary return air box 5, mixes with the low-temperature air processed by the heat exchanger 4, is reheated and heated to reach the designed supply air temperature, and is finally sent to the air-conditioned room through the supply air inlet 7 by the fan. Since the indoor secondary return air temperature is around 26 degrees, when it flows through the fan motor 11, it is beneficial to the heat dissipation of the fan motor 11.

[0010] When heating is in operation in winter, the fresh air inlet 1 and the primary return air inlet 2 are fully opened, the secondary return air inlet 8 is slightly opened, the fan is started, and the heat medium of the heat exchanger 4 is connected. Under the suction of the fan, the indoor primary return air passes through the primary return air inlet 2, and the outdoor fresh air passes through the fresh air inlet 1 to enter the primary return air box 3, and is sent to the heat exchanger 4 after mixing, and the air is heated, and then sent to the secondary return air box 5. Since the secondary return air inlet 8 is slightly opened, a small amount of indoor return air with a relatively low temperature passes through the secondary return air inlet 8 and enters the secondary return air duct 9 under the suction of the fan, flows through the fan motor 11, cools the motor, and then enters the secondary return air box 5, mixes with the hot air processed by the heat exchanger 4, reaches the designed supply air temperature, and is finally sent to the air-conditioned room through the supply air inlet 7 by the fan. Since a small amount of low-temperature return air in the room enters the secondary return air duct 9, the entry of high-temperature air is prevented, the heat dissipation of the fan motor 11 is ensured, and the supply air temperature is less affected.

[0011] Figure 3 In the figure, an upper cover plate 17 is added at the upper air outlet of the secondary return air duct 9, and a ventilation hole 18 is opened at the upper part of the secondary return air duct 9. The secondary return air enters the secondary return air box 5 from the ventilation hole 18 and the air duct notch 13. Due to the addition of the upper cover plate 17, hot air can be effectively prevented from entering the secondary return air duct 9, which is beneficial to the heat dissipation of the fan motor 11.

[0012] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A return air reheating fan coil unit, comprising a fan, a heat exchanger, a primary return air box, a secondary return air box, a fresh air inlet, a primary return air inlet, a secondary return air inlet, a secondary return air duct, and an air supply inlet, wherein: The primary return air box is provided with a fresh air inlet and a primary return air inlet, the secondary return air box is provided with a fan, a secondary return air inlet, a secondary return air duct, and an air supply inlet. The primary return air box is connected to the air inlet of the heat exchanger, and the air outlet of the heat exchanger is connected to the secondary return air box. The fan is installed in the secondary return air box, which includes a volute, a wind wheel, and a motor. Its air intake is connected to the secondary return air box, and the air outlet is connected to the air supply inlet of the secondary return air box. The secondary return air duct is installed in the secondary return air box, the lower air inlet is connected to the secondary return air inlet, the upper air outlet is connected to the secondary return air box, and is connected to the secondary return air box shell, the upper air outlet is higher than the fan motor, and the fan motor is mounted therein, and all the air intake from the secondary return air inlet flows through the fan motor and then enters the secondary return air box.

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