Air conditioner of return air reheating type

Abstract

The utility model air conditioner of return air reheating type, it includes fan -coil, primary return air tank, secondary return air tank, secondary return air blower, air supply pipe, air supply outlet, its characterized is, fan -coil air inlet connects primary return air tank, air outlet connects air supply pipe, primary return air tank has primary return air and fresh air, primary return air connects indoor return air, fresh air connects outdoor fresh air, secondary return air tank has secondary return air, secondary return air blower is installed in secondary return air tank, its air suction port intercommunication secondary return air, its air outlet has check valve, and connects air supply pipe, there is the partition of baffle between primary return air tank and secondary return air tank, and the end of air supply pipe is equipped with air supply outlet, when summer operation, the low temperature cold air of fan -coil processing mixes with secondary return air, makes air supply reheating, improves air supply temperature, human body has no cold air feeling, it is installed in the ceiling, cancels air conditioning room, saves the investment for the customer, and is convenient for operation regulation.

Description

Technical Field

[0001] This utility model belongs to the field of ventilation and air conditioning, and specifically relates to a return air reheat type air conditioner. Background Technology

[0002] Existing variable air volume (VAV) air conditioning systems in office buildings supply air to various office rooms through air conditioning machine rooms. The large duct size increases the building height and occupies a large building space. The control system at the air supply terminal is very complex. Even if a fan coil unit plus fresh air air conditioning system is used, a fresh air machine room still needs to be set up, which increases the construction cost. Therefore, this kind of centralized large-scale central air conditioning system has a complex structure, large investment, and is difficult to operate and adjust. Summary of the Invention

[0003] The purpose of this utility model is to provide a small, decentralized return air reheat air conditioner that can replace the existing central air conditioning unit, eliminate the need for an air conditioning room, reduce building height, save investment, and is simple to operate and adjust, making it easy to maintain and manage.

[0004] The solution of this utility model is: a reheat air conditioner, which includes a fan coil unit, a primary return air box, a secondary return air box, a secondary return air fan, a supply air duct, and a supply air outlet. The fan coil unit's inlet is connected to the primary return air box, and its outlet is connected to the supply air duct. The primary return air box has a primary return air outlet and a fresh air outlet. The primary return air outlet connects to indoor return air, and the fresh air outlet connects to outdoor fresh air. The secondary return air box has a secondary return air outlet. The secondary return air fan is installed in the secondary return air box, with its intake connected to the secondary return air outlet. Its outlet has a backflow preventer and is connected to the supply air duct. A partition separates the primary and secondary return air boxes, preventing ventilation. One or more supply air outlets are installed at the end of the supply air duct, either in the ceiling, in a freestanding or wall-mounted configuration. The fan coil unit connects to the air conditioner's hot or cold water or refrigerant. The fan in the fan coil unit and the secondary return air fan are variable speed fans.

[0005] When the cooling system is running in summer, the fresh air inlet, primary return air inlet, and secondary return air inlet are opened. The fan coil unit and secondary return air fan are started, and the refrigerant is connected to the fan coil unit. Under the suction of the fan coil unit and the secondary return air fan, indoor return air enters the primary return air box through the primary return air inlet, and outdoor fresh air enters through the fresh air inlet. After mixing, the air is sent to the heat exchange coil by the fan coil unit fan to cool and dehumidify the air to the dew point state, and then sent into the supply air duct. Another part of the indoor return air with a higher temperature enters the secondary return air box through the secondary return air inlet under the suction of the secondary return air fan, and is sent into the supply air duct by the secondary return air fan. It mixes with the low-temperature air treated by the fan coil unit, reheats it, and increases the supply air temperature to the air conditioning design supply air point. Then it is sent to the room through the supply air outlet. Because the supply air temperature is increased, users do not feel cold air, thus improving comfort. By adjusting parameters such as the opening degree of the fresh air inlet and return air inlet, the speed of the fan coil unit and return air fan, and the flow rate of refrigerant in the fan coil unit, the system achieves balanced and stable operation through an automatic control system.

[0006] When heating is running in winter, open the fresh air inlet and the primary return air inlet, start the fan coil unit, stop the secondary return air fan, close the back air check valve, and connect the heat medium to the fan coil unit. Under the suction of the fan coil unit, the indoor return air enters the primary return air box through the primary return air inlet and the outdoor fresh air enters through the fresh air inlet. After mixing, the air is sent to the heat exchange coil by the fan of the fan coil unit to heat the air to reach the design temperature. Then it is sent into the air supply duct and then sent to the room through the terminal air supply outlet.

[0007] Since the reheated heat comes from the indoor return air, there is no increase in heat load, achieving energy saving. At the same time, it increases the supply air temperature and reduces relative humidity, achieving the designed supply air parameters and improving human comfort. It can also handle fresh air, possessing the functions of a central air conditioning unit. It transforms a centralized air conditioning room into a distributed small air conditioner, eliminating the need for a dedicated air conditioning room, saving customers investment, and facilitating operation and adjustment. It is not limited to the above structure and has various other construction methods. Attached Figure Description

[0008] Figure 1 It is a reheat air conditioner. Figure 1 Figure 2 It is a reheat air conditioner. Figure 2 Figure 3 It is a reheat air conditioner. Figure 3 Figure 4 It is a reheat air conditioner. Figure 4 Figure 5 It is a reheat air conditioner. Figure 5 Figure 6 It is a reheat air conditioner. Figure 6 Figure 7 It is a reheat air conditioner. Figure 7 Figure 8 It is a reheat air conditioner. Figure 8 Explanation of reference numerals in the attached figures: 1. Fan coil unit; 2. Primary return air box; 3. Primary return air inlet; 4. Fresh air inlet; 5. 20. Partition; 6. Secondary return air inlet; 7. Secondary return air box; 8. Secondary return air fan; 9. Check valve; 10. Air supply duct; 11. Air supply outlet; 12. Humidifier; 13. Condensate outlet; 14. Refrigerant pipe; 15. Wet heat exchanger; 16. Dry heat exchanger; 17. Fresh air fan; 18. Primary return air fan; 19. Fresh air box. Detailed Implementation

[0009] Figure 1 The reheat air conditioner includes a fan coil unit 1, a primary return air box 2, a secondary return air box 7, a secondary return air fan 8, a supply air duct 10, and a supply air outlet 11. Its features include: the fan coil unit 1 has its air inlet connected to the primary return air box 2 and its air outlet connected to the supply air duct 10; the primary return air box 2 has a primary return air outlet 3 and a fresh air outlet 4; the primary return air outlet 3 connects to indoor return air, and the fresh air outlet 4 connects to outdoor fresh air; the secondary return air box 7 has a secondary return air outlet 6; the secondary return air fan 8 is installed in the secondary return air box 7, its air inlet is connected to the secondary return air outlet 6, and its air outlet has a backflow preventer 9 and is connected to the supply air duct 10; a partition 5 separates the primary return air box 2 and the secondary return air box 7. The sealed partition is not ventilated. At the end of the air supply duct 10, there is one or more air supply outlets 11, which are installed in the ceiling, either as a freestanding unit or a wall-mounted unit. The refrigerant pipe 14 of the fan coil unit 1 is connected to the air conditioning chilled or hot water or refrigerant. The fan of the fan coil unit 1 and the secondary return air fan 8 are variable speed fans, usually three-speed variable speed fans. The air volume of the secondary return air fan 8 is between 30% and 100% of the air volume of the fan coil unit 1. The air pressure of the two is the same. The secondary return air fan 8 uses a centrifugal fan or an axial flow fan. The backflow preventer 9 in the figure is a suspended plate type air valve. When the secondary return air fan 8 stops, the suspended plate falls to prevent backflow of the supplied air. Other types of backflow preventers can also be used. Fan coil unit 1 uses existing fan coil units without changing their structure, only increasing the fresh air load. It is installed in the ceiling, with the return air vent and supply air vent installed on the ceiling, and the fresh air vent connected to the indoor fresh air duct or window, or it can be a floor-standing cabinet type or a wall-mounted type.

[0010] When the cooling system is running in summer, the fresh air inlet 4, primary return air inlet 3, and secondary return air inlet 6 are opened. The fan coil unit 1 and secondary return air fan 8 are started. The refrigerant of the fan coil unit 1 is connected. Under the suction of the fan of the fan coil unit 1 and the secondary return air fan 8, the indoor return air enters the primary return air box 2 through the primary return air inlet 3 and the outdoor fresh air enters the primary return air box 2 through the fresh air inlet 4. After mixing, the air is sent to the heat exchange coil by the fan of the fan coil unit 1 to cool and dehumidify the air to the dew point. Then it is sent into the supply air duct 10. Another part of the indoor return air with a higher temperature enters the secondary return air box 7 through the secondary return air inlet 6 under the suction of the secondary return air fan 8. It is then sent into the supply air duct 10 by the secondary return air fan 8 and mixes with the low temperature air treated by the fan coil unit 1 to reheat it and increase the supply air temperature to the air conditioning design supply air point. Then it is sent to the room through the supply air outlet 11. Because the supply air temperature is increased, the user does not feel cold air, thus improving comfort. By adjusting parameters such as the opening degree of the fresh air inlet and return air inlet, the speed of the fan coil unit and return air fan, and the flow rate of refrigerant in the fan coil unit, the system achieves balanced and stable operation through an automatic control system. When the secondary return air mixes with the cold air treated by the fan coil unit 1, condensate may be generated, which can be drained through the condensate drain outlet 13, and the supply air duct 10 is insulated.

[0011] When operating in heating mode during winter, open the fresh air inlet 4 and the primary return air inlet 3, start the fan coil unit 1, stop the secondary return air fan 8, close the return air valve 9, and connect the heat medium to the fan coil unit 1. Under the suction of the fan coil unit 1, indoor return air enters the primary return air box 2 through the primary return air inlet 3, and outdoor fresh air enters through the fresh air inlet 4. After mixing, the air is sent to the heat exchange coil by the fan of the fan coil unit 1 to heat the air to the design temperature, and then sent into the air supply duct 10, and finally sent to the room through the terminal air supply outlet 11. When the air is dry, the humidifier 12 can be turned on to humidify the air.

[0012] Since the heat from the reheating comes from the indoor return air, there is no increase in heat load, thus achieving energy saving. At the same time, it increases the supply air temperature and reduces the relative humidity, achieving the designed supply air parameters and improving human comfort. It can also handle fresh air, possessing the functions of a central air conditioning unit. It transforms a centralized air conditioning room into a distributed small air conditioner, eliminating the need for an air conditioning room, saving customers investment, and facilitating operation and adjustment.

[0013] Figure 2In the middle section, the secondary return air fan 8 is installed at the air supply outlet 11. It is a centrifugal fan, and its air intake is connected to the secondary return air outlet 6 below. The secondary return air outlet 6 and the air supply outlet 11 are flush with the ceiling, and its air outlet is connected to the air supply duct 10. The secondary return air outlet 6 and the air supply outlet 11 can share a single air outlet at the ceiling or be set up separately to reduce short-circuit air volume. When the cooling operation is in summer, the secondary return air fan 8 sends the high-temperature indoor return air into the air supply duct 10, mixes it with the treated low-temperature air, and reheats it to increase the supply air temperature to reach the air conditioning design supply air point. Then, it is delivered to the room through the air supply outlet 11. When the heating operation is in winter, the secondary return air fan 8 is stopped, and the hot air treated by the fan coil unit 1 is delivered to the room through the air supply outlet 11. At this time, the secondary return air outlet 6 can be left open, and part of the supply air is delivered to the room through the secondary return air fan and the secondary return air outlet 6.

[0014] Figure 3 In the middle, the secondary return air fan 8 is installed at the air supply outlet 11. It is an axial flow fan. Its air intake is connected to the secondary return air outlet 6 below. The secondary return air outlet 6 and the air supply outlet 11 are flush with the ceiling. Its air outlet is connected to the air supply pipe 10. The secondary return air outlet 6 and the air supply outlet 11 can share a single air outlet or be set separately at the ceiling to reduce short-circuit air volume.

[0015] Figure 4 , 5 In this configuration, the secondary return air fan 8 is mounted on the supply air duct 10, away from the supply air outlet 11. It is an axial flow fan, with its intake connected to the secondary return air outlet 6 below. The secondary return air outlet 6 is flush with the ceiling, and its outlet is equipped with a backflow preventer 9, which connects to the supply air duct 10. During summer cooling operation, the secondary return air fan 8 draws high-temperature indoor return air into the supply air duct 10, mixes it with treated low-temperature air, reheats it, and raises the supply air temperature to the air conditioning design supply point. The air is then delivered to the room through multiple supply air outlets 11. During winter heating operation, the secondary return air fan 8 stops, and the hot air treated by the fan coil unit 1 is delivered to the room through the supply air outlets 11. At this time, the backflow preventer 9 is closed, and the secondary return air outlet 6 is not ventilated. The secondary return air fan 8 can also be a centrifugal fan. It is installed in the ceiling, either as a floor-standing unit or a wall-mounted unit. When the room area is large and multiple supply air outlets 11 are required, this type of reheat air conditioner can be used.

[0016] Figure 6 In the middle, it is to put Figure 1The wet fan coil unit 1 has been replaced with a temperature and humidity independently controlled fan coil unit. It includes a temperature and humidity independently controlled fan coil unit, a fresh air box 19, a primary return air box 2, a secondary return air box 7, a secondary return air fan 8, an air supply duct 10, and an air outlet 11. The characteristic feature is that the temperature and humidity independently controlled fan coil unit includes a wet heat exchanger 15, a fresh air fan 17, a dry heat exchanger 16, and a primary return air fan 18. The fresh air box 19 has a fresh air inlet 4 connected to outdoor fresh air. The fresh air fan 17 is installed in the fresh air box 19, with its air intake connected to the fresh air inlet 4 and its air outlet connected to the wet heat exchanger 15. The air inlet of the wet heat exchanger 15 is connected to the air supply duct 10; the primary return air box 2 has a primary return air outlet 3, and the primary return air fan 18 is installed in the primary return air box 2. Its air inlet is connected to the primary return air outlet 3, and its air outlet is connected to the air inlet of the dry heat exchanger 16. The air outlet of the dry heat exchanger 16 is connected to the air supply duct 10; the secondary return air box 7 has a secondary return air outlet 6, and the secondary return air fan 8 is installed in the secondary return air box 7. Its air inlet is connected to the secondary return air outlet 6, and its air outlet has a check valve 9 and is connected to the air supply duct 10; the primary return air box 2 and the secondary return air box 7 are connected by... There is a sealed partition 5 that prevents ventilation. A partition 20 separates the primary return air box 2 from the fresh air box 19, also preventing ventilation. One or more air outlets 11 are installed at the end of the supply air duct 10. These outlets are installed in the ceiling, either as freestanding units or wall-mounted units. The air conditioning refrigerant first enters the wet heat exchanger 15, whose refrigerant outlet connects to the refrigerant inlet of the dry heat exchanger 16. Finally, the air conditioning refrigerant flows out from the dry heat exchanger 16. The refrigerant pipe 14 connects to the air conditioning chilled / hot water or refrigerant. The wet heat exchanger 15 and the dry heat exchanger 16 can adopt the existing structure of fan coil heat exchangers, and are not limited to this. The fresh air unit 17, primary return air unit 18, and secondary return air unit 8 are variable speed fans, usually three-speed variable speed fans. The air volume of the secondary return air unit 8 is between 30% and 100% of the sum of the air volumes of the fresh air unit 17 and the primary return air unit 18. The air pressure of the three is the same. They use centrifugal fans or axial fans. The fresh air unit 17 and the primary return air unit 18 use coaxial fans or separate fans. The figure shows a coaxial fan. The backflow preventer 9 in the figure is a suspended plate type air valve. When the secondary return air unit 8 is stopped, the suspended plate falls to prevent backflow of the supplied air. Other types of backflow preventers can also be used.

[0017] When the cooling system is running in summer, open the fresh air inlet 4, the primary return air inlet 3, and the secondary return air inlet 6, and start the fresh air fan 17, the primary return air fan 18, and the secondary return air fan 8. Under the suction of the fans, the outdoor fresh air enters the wet heat exchanger 15, the indoor primary return air enters the dry heat exchanger 16, and the indoor secondary return air enters the air supply duct 10. When the refrigerant pipe 14 is connected, the 7°C air conditioning water or refrigerant first enters the wet heat exchanger 15. The high-temperature and high-humidity fresh air is cooled and dehumidified into low-temperature dew point air, and then enters the air supply duct 10. The 7°C low-temperature air conditioning water, after heat exchange in the wet heat exchanger 15, becomes high-temperature air conditioning water above 12°C. It enters the refrigerant inlet of the dry heat exchanger 16 from the refrigerant outlet of the wet heat exchanger 15. In the dry heat exchanger 16, the indoor primary return air is cooled. The treated dry and cold air enters the air supply duct 10. In this way, the low-temperature fresh air, primary return air and secondary return air are mixed in the air supply duct 10. The secondary return air is reheated, increasing the supply air temperature to the air conditioning design supply air point. Then it is delivered to the room through the air outlet 11. Because the supply air temperature is increased, the user does not feel cold air, improving comfort. Since only the wet heat exchanger 15 is used for cooling and dehumidification, and the dry heat exchanger 16 does not dehumidify, it can be kept dry and mold-free, realizing independent control of temperature and humidity. By adjusting the opening degrees of the fresh air inlet 4, primary return air inlet 3, and secondary return air inlet 6, as well as the speeds of the fresh air fan 17, primary return air fan 18, and secondary return air fan 8, and the refrigerant flow rate, the system achieves balanced and stable operation through an automatic control system. When the secondary return air mixes with the cooled air treated by the fan coil unit, condensate may be generated, which can be drained through the condensate drain inlet 13. The air supply duct 10 is insulated.

[0018] When operating in heating mode during winter, open the fresh air inlet 4 and the primary return air inlet 3, start the fresh air fan 17 and the primary return air fan 18, stop the secondary return air fan 8, close the return air valve 9, and connect the refrigerant pipe 14. The high-temperature air conditioning water or refrigerant first enters the wet heat exchanger 15, and then enters the dry heat exchanger 16. Under the suction of the fan, the low-temperature outdoor fresh air enters the fresh air box 19 through the fresh air inlet 4 and is heated in the wet heat exchanger 15. The indoor return air enters the primary return air box 2 through the primary return air inlet 3, is heated in the dry heat exchanger 16, and then enters the air supply duct 10. After mixing, it reaches the design temperature and is then delivered to the room through the terminal air supply outlet 11. When the air is dry, the humidifier 12 can be turned on to humidify the air.

[0019] Since the heat from the reheating comes from the indoor return air, there is no increase in heat load, thus achieving energy saving. At the same time, it increases the supply air temperature and reduces the relative humidity, achieving the designed supply air parameters and improving human comfort. It can also handle fresh air, possessing the functions of a central air conditioning unit. It transforms a centralized air conditioning room into a distributed small air conditioner, eliminating the need for an air conditioning room, saving customers investment, and facilitating operation and adjustment.

[0020] Figure 7 In the middle, it is to put Figure 2The wet fan coil unit 1 in the middle has been replaced with a fan coil unit with independent temperature and humidity control, and the working principle is the same as above.

[0021] Figure 8 In the middle, it is to put Figure 4 The wet fan coil unit 1 in the middle has been replaced with a fan coil unit with independent temperature and humidity control, and the working principle is the same as above.

[0022] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present utility model shall fall within the protection scope of the present utility model.

Claims

1. A reheat air conditioner, comprising a fan coil unit, a primary return air box, a secondary return air box, a secondary return air fan, supply air ducts, and supply air outlets, characterized in that... The fan coil unit's air inlet connects to the primary return air box, and its air outlet connects to the supply air duct. The primary return air box has a primary return air inlet and a fresh air inlet. The primary return air inlet connects to indoor return air, and the fresh air inlet connects to outdoor fresh air. The secondary return air box has a secondary return air inlet. The secondary return air fan is installed in the secondary return air box, with its air inlet connected to the secondary return air inlet. Its air outlet has a backflow preventer and connects to the supply air duct. There is a partition between the primary and secondary return air boxes to seal them off from ventilation. One or more supply air outlets are installed at the end of the supply air duct. It is installed in the ceiling, either as a freestanding unit or a wall-mounted unit. The fan coil unit connects to the air conditioner's hot or cold water or refrigerant. The fan of the fan coil unit and the secondary return air fan are variable speed fans, and both have the same air pressure.

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