JP7597587B2 - Outdoor air treatment machine - Google Patents

Description

The present invention relates to an outdoor air treatment device that is used in conjunction with an air conditioner to ventilate a room.

Conventionally, in air conditioning to maintain the quality of products in large facilities such as hospitals, elderly care facilities, and large buildings, as well as in production processes in factories, if the amount of air exhausted from inside the room for ventilation is greater than the amount of air supplied from outside, the room will become negative pressure and dirty air will enter through gaps, which can cause the indoor air environment to deteriorate. For this reason, in large facilities that require large amounts of ventilation and exhaust, in addition to air conditioners that adjust the temperature and humidity inside the room, outside air processing machines that process fresh outside air and supply it inside the room are used in combination to adjust the amount of air supplied to the room and the amount of air exhausted from the room to maintain positive or negative pressure inside the room depending on the purpose of the facility.

For example, outdoor air treatment units supply air at a lower temperature than the outside air into the room in summer, and air at a higher temperature than the outside air in winter, eliminating the difference in temperature with the conditioned room, preventing discomfort around the air intake vent inside the room, and also have the function of not placing unnecessary strain on the air conditioner. In recent years, outdoor air treatment units have been provided that use heat pump technology to generate greater thermal energy than electrical energy in order to conserve energy.

As such an outdoor air processing machine (outdoor air processing air conditioner), an air-cooled heat pump type outdoor air processing air conditioner has been disclosed that includes, in the same casing, an outdoor air intake, an exhaust intake that takes in exhaust air from indoors, an evaporator that exchanges heat with outdoor air, a condenser that also serves to recover exhaust heat, a compressor, an air supply fan that blows outdoor air indoors through the evaporator, an exhaust fan that blows exhaust air outdoors through the condenser, an outdoor air damper that adjusts the amount of outdoor air from outdoors to the evaporator, an exhaust damper that adjusts the amount of exhaust air from indoors to the condenser, and an outdoor air intake damper that assists in the amount of air blown to the condenser (see, for example, Patent Document 1).

JP 2002-228187 A

However, when the outdoor air processing machine of Patent Document 1 is used in cold regions in winter, the outdoor air taken into the outdoor air processing machine is low temperature (0°C or lower), so the heating capacity is insufficient and low-temperature air is supplied to the room, making it cold near the air intake port in the room. In addition, the humidification capacity is insufficient and the humidity does not increase. A heat pump used in cold regions requires a special heat pump for cold regions, which is expensive. In addition, when the outdoor air is low temperature, the heat exchanger frequently frosts, so defrosting is necessary. There are various problems such as the above, and the machine could not fully perform its functions, especially in cold regions in winter. In summer (intermediate season), when the outdoor air is cooled and then reheated with refrigerant hot gas, the reheating capacity is insufficient, and the target temperature and humidity may not be achieved.

To solve the above problems, it is possible to place an electric heater unit or a heating coil unit in front of or behind the outdoor air processor to preheat the outdoor air to be taken into the outdoor air processor, but not only would this require extensive installation work, it may not be possible to achieve optimal control including the added equipment.

The present invention has been made to solve the above problems, and aims to provide an outdoor air treatment machine that can be used in cold regions in winter by integrating not only heat pump technology into the outdoor air treatment machine but also a boiler unit that circulates hot water or antifreeze liquid (hereinafter referred to as heat transfer water) at a specified temperature and optimally controlling them simultaneously. It also aims to provide an outdoor air treatment machine that is ideal for facilities that need high-temperature, high-humidity air supply in winter for production processes such as hospitals, elderly care facilities, and factories, even in non-cold regions, in order to maintain product quality.

The present invention is an outdoor air treatment machine that supplies outdoor air with adjusted temperature and humidity to the room, characterized by the fact that it is an integrated package of a heat pump unit for energy saving and a boiler unit for circulating heat transfer water at a predetermined temperature.

The system is also characterized by suppressing defrosting of the heat exchanger by simultaneously controlling the output of the heat pump unit and the output of the boiler unit.

The outdoor air treatment machine of the present invention is an integrated package of a heat pump unit for saving energy and a boiler unit for circulating heat transfer water at a predetermined temperature. As a result, even in cold regions in winter when the temperature of the outdoor air taken into the outdoor air treatment machine is low, the temperature of the outdoor air to be supplied indoors can be preheated by the boiler unit, so that outdoor air with a stable temperature and humidity can be supplied indoors.

In addition, by simultaneously controlling the output of the heat pump unit and the output of the boiler unit, it is possible to suppress defrosting of the heat exchanger of the outdoor air processing unit. In other words, by configuring the heat pump unit and the boiler unit as an integrated unit and optimally controlling them simultaneously in conjunction with each other, it is possible to control frost formation on the evaporator in the outdoor air processing unit, thereby eliminating discomfort such as reduced performance due to defrosting and the feeling of cold air indoors.

FIG. 2 is a diagram showing a configuration of an outside air processing machine according to an embodiment of the present invention. FIG. 2 is a psychrometric chart illustrating changes in temperature of outside air in an outside air processing device in winter according to one embodiment of the present invention. 5 is a flowchart for explaining an outline of defrost suppression control in the outdoor air processing device in winter according to one embodiment of the present invention. FIG. 2 is a psychrometric chart illustrating changes in temperature of outside air in an outside air processing device in summer (intermediate season) according to one embodiment of the present invention.

The present invention relates to an outdoor air treatment machine that supplies outdoor air with adjusted temperature and humidity to a room, characterized by the fact that it is an integrated package of a heat pump unit for energy conservation and a boiler unit for circulating heat transfer water at a specified temperature.

Below, an outdoor air treatment machine according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing the configuration of an outdoor air treatment machine according to an embodiment of the present invention. FIG. 2 is an psychrometric chart explaining the temperature change of outdoor air in an outdoor air treatment machine in winter according to an embodiment of the present invention. FIG. 3 is a flow chart explaining an overview of defrost suppression control in an outdoor air treatment machine in winter according to an embodiment of the present invention. FIG. 4 is an psychrometric chart explaining the temperature change of outdoor air in an outdoor air treatment machine in summer (intermediate season) according to an embodiment of the present invention.

As shown in FIG. 1, the outdoor air processing machine 1 of this embodiment is configured by unitizing various devices in the upper casing KH, middle casing KM, and lower casing KL, which are box-shaped and made of metal (e.g., iron or aluminum). The uppermost upper casing KH has left and right openings, and by operating the exhaust fan 30 installed at the top, it draws in outdoor air OA from the left and right openings and exhausts it to the top. Condensers 20 are installed near the left and right openings of the upper casing KH. During summer operation, the condenser 20 is a heat exchanger that cools the high-pressure, high-temperature refrigerant gas inside with the outside air OA and condenses and liquefies it. The condensed and liquefied refrigerant gas is circulated to the evaporator 21 and reheater 22 described below via the refrigerant piping 25.

The middle casing KM is configured with left and right openings, just like the upper casing KH. The right opening of the middle casing KM is an intake for outside air OA, which is adjusted in temperature and humidity and supplied to the room as supply air SA from the left opening of the middle casing KM. Heat transfer water coils 13 are installed near the left and right openings of the middle casing KM. The heat transfer water coils 13 are composed of multiple heat transfer water circulation pipes that circulate the heat transfer water circulating through the heat transfer water piping 12 inside, and adjust the temperature of the outside air OA taken in from the right opening of the middle casing KM (pre-heating in winter).

An evaporator 21 is disposed to the left of the heat transfer water coil 13 near the right opening of the middle casing KM. The evaporator 21 is a heat exchanger that uses the latent heat of evaporation of the condensed and liquefied refrigerant circulating inside to exchange heat with the outside air OA that flows outside the container from the right to the left of the middle casing KM. For this reason, it is connected to the condenser 20 by refrigerant piping 25, and the condensed and liquefied refrigerant is supplied from the condenser 20.

The reheater 22 is disposed to the left of the evaporator 21. The reheater 22 warms the outside air OA, whose temperature has been reduced by passing through the evaporator 21. In other words, it is called a "reheater" because it functions as a heat exchanger to reheat the cooled air. This reheater 22 is also connected to the condenser 20 by refrigerant piping 25, and condensed and liquefied refrigerant is supplied from the condenser 20. The reheater 22 is configured to use the condensed and liquefied refrigerant hot gas supplied from the condenser 20 as its heat source.

That is, the heat pump unit in this embodiment is composed of the condenser 20 installed near the left and right openings of the upper casing KH, the evaporator 21 and reheater 22 installed in the middle casing KM, and the refrigerant piping 25 connecting them. The condenser 20 and evaporator 21 that constitute the heat pump unit operate with their functions reversed during heating operation in winter and cooling operation in summer. That is, the condenser 20 functions as the evaporator 20 during heating operation in winter, and the evaporator 21 functions as the condenser 21 during heating operation in winter. For this reason, in the following description, the same symbols may be used to refer to the condenser 20, evaporator 20, or evaporator 21, condenser 21.

A humidifier 23 is disposed to the left of the reheater 22. This humidifier 23 imparts a predetermined humidity to the outside air OA flowing from left to right through the upper casing KH. A heat transfer water coil 14 is disposed to the left of the humidifier 23, near the left opening of the middle casing KM. The heat transfer water coil 14 circulates the heat transfer water circulating through the heat transfer water piping 12 inside, thereby performing final temperature adjustment of the outside air OA taken in from the right opening of the middle casing KM, and supplies air at a predetermined temperature from the left opening of the middle casing KM to the room as supply air SA.

The lower casing KL, unlike the upper casing KH and the middle casing KM, is constructed with various devices installed inside. A hot water tank 10 and a boiler 11 are installed on the right side of the lower casing KL, and heat transfer water at a constant temperature is always stored in the hot water tank 10. The heat transfer water stored in the hot water tank 10 is circulated between the hot water tank 10 and the heat transfer water coils 13 and 14, which are connected by the heat transfer water pipe 12, by a pump (P in the figure) installed midway in the heat transfer water pipe 12.

That is, the boiler unit in this embodiment is composed of the heat transfer water coils 13 and 14 installed near the left and right openings of the middle casing KM, the hot water tank 10 installed in the lower casing KL, the boiler 11, and the heat transfer water piping 12 connecting them.

According to the outdoor air treatment device 1 configured as described above, in summer, high-temperature outdoor air OA is cooled by the evaporator 21 of the heat pump unit, and if reheating is required, it is reheated by the reheater 22. If the amount of reheating is insufficient, heat transfer water in the hot water tank of the boiler unit is supplied to the heat transfer water coil 14 to supplement the reheating, so that supply air SA of an appropriate temperature and humidity can be provided to the room. Also, in winter, the temperature of low-temperature outdoor air OA is heated by the condenser 21 of the heat pump unit, and if humidification is required, it is humidified by the humidifier 23. If the temperature cooled by evaporation in the humidifier is low, heat transfer water in the hot water tank of the boiler unit is supplied to the heat transfer water coil 14 and heated, so that supply air SA of an appropriate temperature and humidity can be provided to the room.

Below, an example of the temperature change of the outdoor air OA in the outdoor air processing machine 1 in winter will be described with reference to FIG. 2. The example shown in FIG. 2 shows the temperature change of the outdoor air OA in the outdoor air processing machine 1 installed in a cold region in winter.

As shown in Figure 2, the temperature of the outside air OA taken in from the right opening of the middle casing KM is -15°C (circle 1 in the figure). The temperature of the outside air OA flowing from the right opening to the left opening of the middle casing KM is preheated in the heat transfer water coil 13 that constitutes the boiler unit near the right opening of the middle casing KM and rises to 35°C (circle 2 in the figure). The temperature of the outside air OA rises to 45°C in the condenser 20 of the heat pump unit installed to the left of the heat transfer water coil 13 of the middle casing KM (circle 3 in the figure).

The temperature of the outside air OA, which has been humidity-adjusted by the humidifier 23, drops to 30.7°C as the moisture evaporates from the humidification (circle 4 in the figure). Finally, the temperature of the outside air OA flowing from the right opening to the left opening of the middle casing KM is heated by the heat transfer water coil 14 that constitutes the boiler unit near the left opening of the middle casing KM and rises to 40°C (circle 5 in the figure). Then, the outside air OA heated by the heat transfer water coil 14 from the left opening of the middle casing KM is supplied to the room as supply air SA.

As described above, in this embodiment, the outdoor air treatment machine 1 is configured integrally with not only a heat pump unit but also a boiler unit that circulates heat transfer water at a predetermined temperature, making it possible to provide an outdoor air treatment machine 1 that can be used in cold regions in winter.

The outdoor air processing device 1 in this embodiment is configured to control the integrated heat pump unit and boiler unit in conjunction with each other using a control unit (not shown). That is, by simultaneously controlling the condenser 20, evaporator 21, and reheater 22 that make up the heat pump unit and controlling the temperature using the hot water tank 10, circulation pump P, and boiler 11 that make up the boiler unit, the heat pump unit with the best operating efficiency is operated preferentially, and the boiler unit is operated only when necessary, allowing for optimal control without waste and enabling energy savings.

In addition, in cold regions in winter, the outdoor air OA taken in by the outdoor air processing unit 1 is preheated in advance by the heat transfer water coil 13 constituting the boiler unit, and flows through the condenser 21 constituting the heat pump unit, which is a heat exchanger. This prevents the low-temperature (for example, -15°C) outdoor air OA taken in by the outdoor air processing unit 1 from flowing through the condenser 21 constituting the heat pump unit, which is a heat exchanger, at a low temperature, and compensates for the lack of heating capacity. In addition, when the evaporation temperature of the evaporator 20 of the heat pump unit drops and reaches the defrost detection temperature, the output of the heat pump unit is reduced to raise the evaporation temperature, and then the output of the boiler unit is increased to compensate for the lack of heating capacity, so that the evaporator 20 is less likely to frost, suppressing defrosting, and allowing the system to demonstrate sufficient capacity even in cold regions in winter.

Below, an example of a defrost suppression control method controlled by the outdoor air processing unit 1 of this embodiment will be described with reference to FIG. 3. Note that the following control process will be described as an example of winter heating operation executed by a control program stored in a control unit (not shown) attached to the outdoor air processing unit 1.

In the heating operation process shown in FIG. 3, the defrost setting conditions of the outside air temperature and the evaporation temperature of the evaporator 20 are monitored, and when the conditions are not met, the heat pump unit output is increased or decreased to control toward the supply air set temperature, and when the conditions are met, the heat pump unit output is decreased and the evaporation temperature is increased to prevent frost formation on the evaporator 20. At that time, the heat pump unit's heat transfer water coil output is increased or decreased to control toward the supply air set temperature, and defrosting of the heat pump unit is suppressed.

As shown in FIG. 3, the control unit determines whether the temperature of the outdoor air OA is equal to or lower than the set supply air temperature (step S1). If the control unit determines that the temperature of the outdoor air OA is not equal to or lower than the set supply air temperature (step S1: No), it reduces the output of the heat pump unit (step S2) and proceeds to step S1. On the other hand, if the control unit determines that the temperature of the outdoor air OA is equal to or lower than the set supply air temperature (step S1: Yes), it proceeds to step S3.

The control unit determines whether the temperature of the outside air OA is A (set value) °C and the evaporation temperature is equal to or lower than X (set value) °C (step S3). If the control unit determines that the temperature of the outside air OA is not equal to or lower than A (set value) °C and the evaporation temperature is not equal to or lower than X (set value) °C (step S3: No), it increases the output of the heat pump unit (step S4) and moves the process to step S1. On the other hand, if the control unit determines that the temperature of the outside air OA is equal to or lower than A (set value) °C and the evaporation temperature is not equal to or lower than X (set value) °C (step S3: Yes), it decreases the output of the heat pump unit (step S5) and moves the process to step S6.

The control unit determines whether the temperature of the outside air OA is equal to or lower than the set supply air temperature (step S6). If the control unit determines that the temperature of the outside air OA is not equal to or lower than the set supply air temperature (step S6: No), the process proceeds to step S1. On the other hand, if the control unit determines that the temperature of the outside air OA is equal to or lower than the set supply air temperature (step S6: Yes), the control unit increases the output of the heat transfer water coils 13 and 14 (step S7) and proceeds to step S8.

The control unit determines whether the temperature of the outside air OA is equal to or lower than the set supply air temperature (step S8). If the control unit determines that the temperature of the outside air OA is not equal to or lower than the set supply air temperature (step S8: No), it reduces the output of the heat transfer water coils 13 and 14 (step S9) and proceeds to step S8. On the other hand, if the control unit determines that the temperature of the outside air OA is equal to or lower than the set supply air temperature (step S8: Yes), it proceeds to step S10.

The control unit determines whether the temperature of the outside air OA is A (set value) °C and the evaporation temperature is equal to or lower than X (set value) °C (step S10). If the control unit determines that the temperature of the outside air OA is A (set value) °C and the evaporation temperature is equal to or lower than X (set value) °C (step S10: Yes), it reduces the output of the heat pump unit (step S11) and moves the process to step S10. On the other hand, if the control unit determines that the temperature of the outside air OA is not equal to or lower than A (set value) °C and the evaporation temperature is not equal to or lower than X (set value) °C (step S10: No), it increases the output of the heat transfer water coils 13 and 14 (step S12) and moves the process to step S13.

The control unit determines whether or not to continue the heating operation (step S13). If the control unit determines that the heating operation should be continued (step S13: Yes), the process proceeds to step S1. On the other hand, if the control unit determines that the heating operation should not be continued (step S13: No), the process ends.

Below, an example of the temperature change of the outdoor air OA in the outdoor air processing unit 1 during the summer (intermediate season) will be described with reference to Figure 4.

As shown in FIG. 4, the temperature of the outside air OA taken in from the right opening of the middle casing KM is 23°C (circle 1 in the figure). The temperature of the outside air OA flowing from the right opening to the left opening of the middle casing KM is cooled to 11.3°C by the evaporator 21 of the heat pump unit (circle 2 in the figure), and heated to 22°C by the reheater 22 (circle 3 in the figure). When the supply air set temperature is 25°C, the reheating capacity is insufficient with the refrigerant hot gas alone, so the outside air is heated to 25°C by the heat transfer water coil 14 that constitutes the boiler unit (circle 4 in the figure). The outside air OA heated by the heat transfer water coil 14 from the left opening of the middle casing KM is then supplied to the room as supply air SA.

Although an example of an embodiment of the present invention has been described above, the specific configuration of the present invention is not limited to the above embodiment, and design changes that do not deviate from the gist of the invention are also included in the present invention.

1 Outdoor air treatment machine 10 Hot water tank 11 Boiler 12 Heat transfer water piping 13 Heat transfer water coil 14 Heat transfer water coil 20 Condenser (evaporator in winter)
21 Evaporator (condenser in winter)
22 Reheater 23 Humidifier 25 Refrigerant piping 30 Exhaust fan KH Upper casing KM Middle casing KL Lower casing OA Outside air SA Supply air

Claims (2)

An outdoor air treatment machine that adjusts the temperature and humidity of the outdoor air taken in and supplies it to the room as intake air,
The heat pump unit is installed inside the casing and is controlled by a control unit in cooperation with each other to save energy. The boiler unit circulates heat transfer water at a predetermined temperature .
The heat pump unit comprises:
a first heat exchanger that exchanges heat with the refrigerant circulating inside the casing using outside air flowing inside the casing;
a second heat exchanger that exchanges heat with outside air flowing through the casing by using a refrigerant circulating therein;
a reheater for reheating the outside air that has been heat exchanged by the second heat exchanger;
a refrigerant pipe connecting the first heat exchanger, the second heat exchanger, and the reheater to each other;
The boiler unit includes:
a heat transfer water coil disposed near each of an opening of the casing for taking in outside air and an opening of the casing for supplying supply air to the room;
A hot water storage tank storing heat transfer water that circulates between each of the heat transfer water coils;
a boiler connected to the hot water tank;
An outdoor air treatment machine characterized by : The outdoor air treatment machine according to claim 1 , characterized in that, when the outdoor air temperature falls below a set value, the control unit suppresses defrosting of the first heat exchanger by controlling the output of the heat pump unit to be lowered and the output of the boiler unit to be increased .

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