JPH04270853A - Air conditioning apparatus - Google Patents

Abstract

PURPOSE:To improve dust removing efficiency and ventilating performance by a method wherein an air-conditioning air temperature is corrected according to capacity of a VAV 9 (variable air volume) unit brought into a forced feed mode, in an air- conditioning device having the VAV system to control air-conditioning capacity through regulation of a discharge airflow of air-conditioning air CONSTITUTION:An air conditioning apparatus having a VAV system is provided with an indoor unit 1 containing a feed air producing means 4 to produce air-conditioning air the temperature of which is regulated to a target value. A plurality of VAV units 31 discharging air-conditioning air from a blower 5 through regulation of a discharge airflow so that an airflow is adjusted to a target value at each of a plurality of zones Z in a room and being switched to a forced feed mode, where a discharge airflow is increased, when a feed air amount is in short supply are provided. In this case, An air-conditioning capacity detecting means 42 to detect the unit 31, brought into a forced feed mode, from a plurality of the VAV units 31 is provided. The target temperature of the feed air producing means 4 is corrected by means of a correction means 43 so that necessary air-conditioning capacity is achieved by the unit 31 brought into a forced feed mode.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner equipped with a VAV system (Variable Air Volume System) that controls air conditioning capacity by adjusting the volume of conditioned air.

0002

[Prior Art] Air conditioners employing this type of VAV system have been known for some time.
An example is a variable air volume single duct type. This thing consists of multiple VAV units (
A variable air volume unit (variable air volume unit) is connected to the air outlet of the indoor unit via a duct, and the conditioned air supplied from the indoor unit is distributed to each VAV unit, and each VAV unit adjusts the air volume. The air conditioner is adjusted so that conditioned air is blown out to multiple zones within the room.

[0003] In this case, for example,
As shown in Publication No. 7497, etc., the temperature of the conditioned air generated in the indoor unit is a constant temperature (VA
The temperature is adjusted to the temperature at which the air conditioning capacity is 100% when 100% air volume is blown out from the V unit), and each VAV unit adjusts the air volume to a temperature proportional to the difference between the actual room temperature of the zone to be air-conditioned and the set temperature. The VAV unit uses proportional control to maintain the room temperature in each zone at the set temperature by adjusting the amount of air blown (air supply amount) according to increases and decreases in the heat load of the zone. It is possible to control the capacity for each. In some cases, the supply air temperature may be shifted so that the room temperature in the zone with the least load does not fall below the set temperature.

[0004] Furthermore, in order to reduce blower power and noise, fan controls such as constant static pressure control and variable static pressure control are performed, and air conditioning is partially stopped using a fully enclosed VAV unit. Sometimes. The static pressure constant control described above is achieved by installing a static pressure detection chamber at the air outlet of the indoor unit, placing a static pressure sensor there to detect the static pressure, and using an output variable means such as an inverter to control the output of the blower motor. change the
Feedback control is performed so that the detected static pressure converges to a target value. On the other hand, as shown in, for example, Japanese Unexamined Patent Publication No. 61-130747, static pressure variable control
It detects the full open signal of the AV unit and the degree of air volume achievement, and if there is a VAV unit that is fully open but the air volume has not been achieved, the fan rotation speed is increased, and conversely, even if all VAV units are not fully open. When the air volume is achieved, the static pressure inside the duct is minimized by lowering the fan rotation speed.

However, as described above, when the temperature of the conditioned air is controlled to a constant temperature and the air conditioning capacity is controlled only by the amount of air blown from each VAV unit, there are no problems at all. In other words, this is good when the air conditioning load is large, but when the load becomes low, the amount of air blown out must be reduced accordingly, and this is particularly noticeable in VAV units that require low performance. As a result, problems arise, such as a reduction in the amount of internal air circulation (return air amount), resulting in a reduction in the dust removal efficiency of the filter, and a reduction in the amount of outside air introduced, resulting in a reduction in ventilation performance.

[0006] Therefore, the degree of air pollution in each indoor zone is detected as a carbon dioxide concentration using a CO2 concentration sensor, as shown in, for example, Japanese Patent Application Laid-open No. 159046/1983, and when this carbon dioxide concentration exceeds a predetermined value, When the amount of air is increased, the air supply mode of the VAV unit located in the zone is forcibly switched to forced air supply mode where the air volume increases.
It is possible to try to improve dust removal efficiency and ventilation performance.

[0007]

[Problem to be solved by the invention] However, in that case, conditioned air at a constant temperature is forcibly supplied, so even though there is no request to increase or decrease the air conditioning capacity, excessive air conditioning capacity is generated. This causes problems such as being too cold (when cooling) or too warm (when heating).

[0008] The present invention has been made in view of the above points, and its purpose is to change the control form of the air conditioning capacity for a VAV unit in forced air supply mode.
While maintaining its air conditioning capacity appropriately, it ensures a large amount of air flow,
It is an attempt to relieve discomfort such as being too cold or too warm.

[0009]

[Means for Solving the Problem] In order to achieve this object, the invention of claim 1 focuses on the fact that the air conditioning capacity of each VAV unit is related not only to the blowout volume of conditioned air but also to its temperature. However, this conditioned air temperature is corrected to match the VAV unit in forced air supply mode.

That is, in the present invention, as shown in FIG. 1, an indoor unit (1) and a plurality of VAV units (31), ( 31),... is assumed. The indoor unit (1) includes a supply air generation means (4) that generates conditioned air adjusted to a target temperature;
A blower (5) for blowing the conditioned air generated by the air supply generating means (4) is built-in. On the other hand, the VAV units (31), (31), ... are respectively arranged in multiple zones (Z), (Z), ... indoors, and each of them sets the target air volume for each zone (Z). The conditioned air from the blower (5) is blown out by adjusting the blowout air volume to reach the target air volume, and when the zone (Z) is in a state where the air supply is insufficient, forced air supply is performed in which the blowout air volume is increased. mode.

[0011] For this air conditioner, among the plurality of VAV units (31), (31),...
Air supply mode detection means (42) detects the VAV unit (31) in forced air supply mode;
Supply air temperature correction means (43) for correcting the target temperature of the conditioned air by the supply air generation means (4) is provided so that the necessary air conditioning capacity is achieved in the V unit (31).

In the invention according to claim 2, each of the VAV units (31) includes a CO2 concentration sensor (35) that detects the concentration of carbon dioxide in the air as air pollution in the zone (Z).
), and is configured to switch to forced air supply mode when the carbon dioxide concentration is equal to or higher than a set value (L).

[0013]

[Operation] In the invention of claim 1, the VAV unit (31) switched to the forced air supply mode is detected by the air supply mode detection means (42), and the air supply temperature correction means (43) detects the amount of air blown out. Increased VAV units (31
) to achieve the required air conditioning capacity with the supply air generation means (
The target temperature of the conditioned air in step 4) is shifted. Therefore, even if the amount of air blown from the VAV unit (31) increases due to forced air supply mode, its air conditioning capacity remains at the original target value, and the temperature of the conditioned air blown out remains constant. It is possible to prevent excessive cooling or overheating. In addition, due to the increase in air volume due to forced air supply mode, even in VAV units (31) with small required capacity, the air volume is kept relatively large and the drop in air volume is small, and the dust removal efficiency and ventilation performance of the filter are significantly reduced. do not. Therefore, the comfort of the air conditioner can be improved.

In the invention of claim 2, the VAV unit (31) switches to the forced air supply mode when the carbon dioxide concentration in the air in the zone (Z) is equal to or higher than the set value (L). Therefore, the comfort during forced air supply can be improved by increasing the carbon dioxide concentration.

[0015]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to FIG. 2 and the following figures.

FIG. 2 shows the overall configuration of an air conditioner according to an embodiment of the present invention. This air conditioner basically consists of 1
1 indoor unit (1) and 3 VAV units (3
1), (31),... The downstream ends of outside air and inside air intake ducts (8) and (9) are connected to the housing (2) of the indoor unit (1), and the upstream end of the outside air intake duct (8) opens to outside air. Intake port (10
), and an outside air intake damper (11) is disposed in the middle. On the other hand, the upstream end of the inside air intake duct (9) is connected to the inside air intake (12) that opens at a predetermined position in the room, and there is a return air blower (13) and a inside air intake damper (
14) are arranged in order from the upstream side. The upstream end of the exhaust duct (15) is branched and connected to the duct (9) downstream of the return air blower (13) and upstream of the internal air intake damper (14) via a switching damper (16). The downstream end of the exhaust duct (15) is connected to an exhaust port (17) that opens outdoors. Then, the outside air intake damper (11) is closed, the inside air intake damper (14) is opened, and the switching damper (16) is opened so that the inside air intake duct (9) is disconnected from the exhaust duct (15). When the switch is switched, the return air blower (13) sucks the inside air (return air) taken in from the inside air intake port (12) into the housing (2) through the inside air intake duct (9). to cool or heat the room. On the other hand, the outside air intake damper (1
1), close the inside air intake damper (14), and then switch the switching damper (16) to open the return air blower (1).
3) Connect the downstream air intake duct (9) to the exhaust duct (15)
), the return air blower (13)
The inside air taken in from the inside air intake (12) is transferred to the exhaust port (17).
), and the outside air taken in from the outside air intake port (10) is sucked into the housing (2) through the outside air intake duct (8), thereby ventilating the room while cooling and heating it. ing.

[0017] Inside the housing (2) is a filter (3).
), an indoor heat exchanger (4), and a blower (5) driven by a motor (not shown). The indoor heat exchanger (4) is connected to an outdoor unit (not shown) and refrigerant piping (
6), the air sucked into the housing (2) is filtered by the filter (3), and then heat exchanged by the heat exchanger (4) to generate conditioned air (supply air); This conditioned air is blown out from inside the housing (2) by a blower (5).

The upstream end of a blow-off duct (18) is connected to the outlet of the blower (5) of the indoor unit (1), and the downstream end of this duct (18) is connected to three branch ducts (18a).
, (18a), ... and different zones in the room (
Air outlets (19), (19,
)..., and the VAV units (31) are arranged in the middle of each of the branch ducts (18a). Each VAV unit (31) sets a target air volume based on the room temperature and set temperature in each zone (Z), adjusts the blowout air volume so that the actual air volume becomes the target air volume,
While blowing out the conditioned air from the blower (5),
The carbon dioxide concentration in the air in zones (Z), (Z), ... is higher than the specified level and the degree of contamination is large;
...Forcibly increases the amount of air blown when there is a shortage of air supply. That is, VAV units (3
1) includes a room temperature detection thermometer (32) that detects the actual room temperature in each zone (Z), and a room temperature setting section (33) that sets the set temperature (Ts) of the room temperature. , a CO2 sensor (34) as a supply air amount shortage detection means that detects the carbon dioxide concentration in the air in the zone (Z) and determines the supply air amount shortage state (ventilation required state), and the air outlet (19). )
Air volume adjustment damper (36
), the target air volume is calculated based on the room temperature detected by the room temperature detection thermometer (32) and the set temperature (Ts ) by the room temperature setting unit (33), and the air volume is adjusted so that the actual air volume becomes equal to this target air volume. While controlling the damper (36),
When the CO2 sensor (34) detects an insufficient supply air amount, the air volume adjustment damper (36) is increased to a predetermined opening degree regardless of the room temperature and set temperature (Ts), and the air volume is forced to increase. A target air volume calculation section (37) for switching to air supply mode is provided.

As shown in FIG. 4, the CO2 sensor (34) determines that the zone (Z) is in a state of insufficient air supply when the detected carbon dioxide concentration is equal to or higher than the set value (L). This CO2 sensor (3
4), the target air volume calculation unit (37) switches the air supply mode to the forced air supply mode. Furthermore, when the carbon dioxide concentration drops to a concentration lower than the above set value (L) by a predetermined concentration (δL), the forced air supply mode returns to the normal mode by stopping the signal output from the CO2 sensor (34). This reference value differential prevents hunting when switching between forced air supply mode and normal mode.

Furthermore, when the target air volume is calculated by the target air volume calculation section (37) in the normal mode, for example during cooling, the room temperature and the set temperature (Ts) are calculated as shown in FIG.
For example, if the room temperature is lower than the set temperature (Ts),
．． When the temperature is lower than 4°C, change the target air volume to the rated air volume (10
0%), and when the difference between the room temperature and the set temperature (Ts) is -0.4°C to +1°C, the target air volume is proportionally increased from 30% to 100% according to the temperature difference. When the temperature difference is +1°C or more, the target air volume is fixed at 100%.

Again, as shown in FIG. 2, the pipe (6) connected to the heat exchanger (4) of the indoor unit (1) includes:
A flow rate adjustment valve (7) is provided to adjust the flow rate of refrigerant to the heat exchanger (4), and by controlling the opening degree of this flow rate adjustment valve (7), air is blown out from the blower (5) of the indoor unit (1). The temperature of the conditioned air is controlled.

[0022] The opening degree of the flow rate regulating valve (7) is controlled by a control unit (41). As shown in FIG. 3, this control unit (41) includes a supply air temperature thermometer (50) that detects the temperature of the conditioned air (supply air) blown out from the blower (5), and each VAV unit (31). The control unit (41) controls the air conditioning based on the supply air temperature thermometer (50) and the signal from the target air volume calculation unit (37) of each VAV unit (31). A target value of the air temperature, that is, a target supply air temperature (T1t) is calculated, and the opening degree of the flow rate regulating valve (7) is feedback-controlled so that the conditioned air temperature becomes the target temperature (T1t).

[0023] Here, the control procedure performed by the control unit (41) during cooling of the air conditioner will be explained in detail with reference to FIG. First, in step S1 after the start, the flag (KKM) indicating the forced air supply mode is changed to the previous flag (KKM) or each VAV unit (31
) is in forced air supply mode, the flag (
KKMi) (where i=1 to 3). Next, in step S2, the flag (KKM) is set to KKM.
= 1, and if this determination is NO (KKM = 0), which VAV unit (31), (31)
,... are not in the forced air supply mode, so proceed to step S3, and set the target temperature (T1t) of the conditioned air so that when each VAV unit (31) is at the rated air volume, the air conditioning capacity (cooling capacity) becomes the rated capacity. The initial value (T1MA
X) (=for example, 13°C), step S1
Return to

On the other hand, in step S2, KKM=1
If the determination is YES, the process proceeds to step S4, where it is determined whether the timer has timed up. This timer measures a fixed period, and counts one minute as described later. If it is determined that the time is up, i=1 in step S5, and the temperature difference (δT1) to (δT3) between the room temperature and the set temperature (Ts) is set in step S8, which will be described later. The minimum value in (δ
After setting δT=0, in steps S6 to S9,
A VAV unit (31) in forced air supply mode is detected. That is, in step S6, i=n (however,
When this determination is NO (i≠n), it is determined whether the flag (KKMi) is KKMi =1. When this determination is YES with KKMi = 1, three VAV units (31
), (31), ..., the temperature difference (δT1) to (δT3) between the room temperature and the set temperature (Ts), and the previous value (
Select the minimum value from among δT) and set it as the new minimum value (
δT), and if the determination is NO that KKMi≠1, the process directly proceeds to step S9. In this step S9, after updating i=i+1, step S
Return to step 6 and repeat the same procedure for i=2 and 3, respectively. Thus, three VAV units (31),
A VAV unit (31) in forced air supply mode is detected from (31), ..., and the temperature difference (δT1) between the room temperature and the set temperature (Ts) in that VAV unit (31)
Select the minimum value from (δT3).

[0025] Detection of the above forced air supply mode applies to all VAV
When performed for units (31), (31),..., i
=n, so the determination in step S6 is YES. In this case, the process proceeds to step S10, where it is determined whether the selected minimum temperature difference (δT) is greater than or equal to a certain value (=1.5), and if this determination is YES (δT≧1.5), the detected minimum temperature difference (δT) is Since the VAV unit (31) is required to have a large cooling capacity, the target temperature (T1t) of the conditioned air is set to the above-mentioned initial value (T1MAX) in step S11, and then the process proceeds to step S16.

It is determined in step S10 that δT<1.
5, that is, when the cooling load in the VAV unit (31) for which the forced air supply mode is requested has decreased from the maximum load, the process proceeds to step S12, and the minimum temperature difference (δT) is set to the first set value. (=1.0°C) or higher, and if this determination is YES (δT≧1.0), the target temperature (T1t) of the conditioned air is changed from the previous target temperature (T1t) in step S13. After shifting to the temperature at which the cooling capacity increases by lowering (T1t-0.5)°C by 0.5°C, the process proceeds to step S16.

[0027] Furthermore, the determination in step S12 above is δT.
<1.0, NO, the process proceeds to step S14, where it is determined whether the minimum temperature difference (δT) is less than or equal to the second set value (=0.5°C), and this determination indicates that δT≦0.5. If YES, the target temperature (T1) of the conditioned air is set in step S15.
t) by 0.5°C from the previous target temperature (T1t).
After resetting the temperature to a higher temperature (T1t+0.5)°C at which the cooling capacity decreases, the process proceeds to step S16.

In step S16, a timer is set to one minute. Thereafter, in step S17, the timer is counted, and the process returns to the first step S1.

In this embodiment, three VAV units (31
), (31),... VAV in forced air supply mode
Air supply mode detection means (42) for detecting the unit (31)
) is configured.

Further, in steps S10 to S15, the VAV unit (31) in the forced air supply mode detected by the air supply mode detection means (42) receives the output of the air supply mode detection means (42). In order to achieve the required cooling capacity, the target temperature (T1t) of the conditioned air by the heat exchanger (4) is changed from the initial value (T1MAX) to the correction value (T
Supply air temperature correction means (4
3) is constructed.

Therefore, in the above embodiment, when the air conditioner is cooling, the control unit (41)
The target temperature of the conditioned air generated by the heat exchanger (4)
T1t) is calculated, and the opening degree of the flow rate regulating valve (7) is feedback-controlled so that the temperature of the conditioned air detected by the supply air temperature thermometer (50) reaches the target temperature (T1t). In this state, the VAV units (31), (31), ... are set to forced air supply mode due to an increase in the carbon dioxide concentration in zones (Z), (Z), ... beyond the set value (L). It is detected whether there is a switched VAV unit (31). Then, VAV unit in forced air mode (3
1), that VAV unit (31) is selected, and the target temperature (T1t) of the conditioned air is determined by this VAV unit (31).
The temperature (T1
MAX+0.5) from the initial value (T1MAX). Further, the target value (T1t) of the conditioned air temperature is reviewed every minute set by the timer, and the target value is reset to the initial value (T1MAX) in accordance with an increase in the cooling load.

In this way, when the amount of air blown from the VAV unit (31) in the forced air supply mode increases, the target temperature of the conditioned air is adjusted so that the required air conditioning capacity is achieved in the VAV unit (31). (T1t) is shifted, even though the volume of air blown from the VAV unit (31) increases, its cooling capacity is maintained at the original target value, and the temperature of the conditioned air blown out remains constant. It is possible to prevent the temperature from becoming too cold or too warm.

Moreover, as the air volume increases due to the forced air supply mode, even in the VAV unit (31) with a small required capacity, the air volume is kept relatively large and the drop in air volume is small, and the dust removal by the filter (3) is reduced. Efficiency and ventilation performance do not decrease significantly. The synergistic effect of these actions can improve the comfort of the air conditioner.

[0034] Although the above embodiment is for cooling,
Control can be performed in the same manner during heating.

[0035] The supply air temperature is similarly controlled in the case of a direct expansion type heat exchanger, and the capacity is controlled by the flow rate regulating valve, the capacity of the compressor, etc. Further, in the above embodiment, V
Although the number of AV units (31) is three, it goes without saying that this number may be reduced to two or increased to four or more. Furthermore, it is also possible to detect the insufficient supply air amount based on factors other than the carbon dioxide concentration.

[0036]

As explained above, according to the invention of claims 1 and 2, an indoor unit that blows conditioned air at a predetermined temperature, and an indoor unit that is connected to the indoor unit through a duct, Among the VAV units, for an air conditioner equipped with a plurality of VAV units that adjust the blowout air volume and blow out conditioned air from the indoor unit,
As the degree of pollution such as carbon dioxide concentration in the air increases in the zone, the air volume is increased to detect units in forced air supply mode, and to adjust the conditioned air so that this VAV unit achieves the required air conditioning capacity. By correcting the temperature, the air conditioning capacity of the VAV unit can be maintained at an appropriate level even though the air volume of the VAV unit has increased compared to the forced air supply mode, and the cooling in each zone can be maintained. It is possible to improve the comfort of the air conditioner by eliminating overheating and overheating.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the overall configuration of the present invention.

FIG. 2 is an overall configuration diagram of an air conditioner according to an embodiment.

FIG. 3 is a block diagram showing the configuration of a control system.

FIG. 4 is a diagram illustrating the principle of detecting insufficient air supply using a CO2 concentration sensor.

FIG. 5 is a characteristic diagram for calculating a target air volume in each VAV unit.

FIG. 6 is a flowchart showing a control procedure in a control unit.

[Explanation of symbols]

(1)…Indoor unit (4) Heat exchanger (supply air generation means) (5)...Blower (18)...Blowout duct (31)...VAV unit (34)...Air volume adjustment damper (41)...control unit (42)...Air supply mode detection means (43)…Supply air temperature correction means (50)...Supply air temperature thermometer (L)…carbon dioxide concentration setting value (Z)...Zone

Claims (2)

[Claims] [Claim 1] Built-in supply air generation means (4) for generating conditioned air adjusted to a target temperature, and a blower (5) for blowing the conditioned air generated by the supply air generation means (4). The indoor unit (1) is arranged in a plurality of zones (Z), (Z), ... indoors, respectively, and is branch-connected to the indoor unit (1) via a duct (18), and is connected to each zone. (Z), and adjust the blowout air volume to reach the target air volume to blow out the conditioned air from the blower (5).
When ... is in a state of insufficient air supply, multiple VAV units (
31), (31), ..., which detects the VAV unit (31) in forced air supply mode among the plurality of VAV units (31), (31), ... The mode detection means (42) receives the output of the air supply mode detection means (42), and the air supply generation means ( 4) An air conditioner characterized by comprising a supply air temperature correction means (43) for correcting the target temperature of the conditioned air. 2. Each VAV unit (31) has a CO2 concentration sensor (35) that detects the carbon dioxide concentration as the degree of air pollution in the zone (Z), and the carbon dioxide concentration is set to a set value (L). The air conditioner according to claim 1, wherein the air conditioner switches to forced air supply mode when the above conditions occur.