JP2679418B2 - Air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner provided with a VAV system (Variable Air Volume System) for controlling the air conditioning capacity by adjusting the amount of conditioned air blown out.

[0002]

2. Description of the Related Art Conventionally, an air conditioner employing this type of VAV system has been known.
As an example, there is a single duct type with a variable air flow. In this device, a plurality of VAV units (variable air volume units = variable air volume units) arranged in each zone in the room are connected to the outlet of the indoor unit via a duct, and supplied from the indoor unit. The conditioned air is distributed to each VAV unit, and the amount of the blown air is adjusted by each VAV unit so that the conditioned air is blown to a plurality of zones in the room.

In this case, for example, Japanese Patent Publication No. 60-4
No. 7497, etc., the temperature of the conditioned air generated in the indoor unit is constant (VA) regardless of the air supply amount.
(The temperature at which the air conditioning capacity becomes 100% when a 100% air volume is blown from the V unit is adjusted.) Each VAV unit has an air volume proportional to the difference between the actual room temperature of the zone to be air-conditioned and the set temperature. By performing proportional control for controlling and adjusting the air blowing amount (air supply amount) according to the increase and decrease of the heat load of the zone, the room temperature of each zone is maintained at the set temperature. Capability control is possible every time. In some cases, the supply air temperature may be shifted so that the room temperature of the zone having the minimum load does not fall below the set temperature.

Further, in order to reduce the power of the blower or the blower noise, fan control such as constant static pressure control and variable static pressure control is performed, or air conditioning is partially stopped by a fully-closed VAV unit. Sometimes. In the static pressure constant control, a static pressure detecting chamber is provided at an outlet of an indoor unit, a static pressure sensor is disposed therein to detect a static pressure, and an output of a blower motor is output using an output variable means such as an inverter. To change
The feedback control is performed so that the detected static pressure converges to the target value. On the other hand, the static pressure variable control, as shown in, for example, Japanese Patent Application Laid-Open No.
It detects the fully opened signal of the AV unit and the degree of achievement of the air volume, and if there is a VAV unit that is fully opened and the air volume is not achieved, the fan rotation speed is increased. Conversely, even if all the VAV units are not fully opened. When the air volume is achieved, the static pressure in the duct is minimized by reducing the number of revolutions of the fan.

[0005]

However, when the supply air temperature is controlled to a constant temperature as described above and the air conditioning capacity is controlled only by the blown air volume from each VAV unit, there is no problem at all. That is, it is good when the air-conditioning load is large, but when the load is low, the blown air volume decreases accordingly, which is particularly noticeable in VAV units that require low capacity. Along with this, there are problems that the amount of circulating internal air (returning air amount) decreases and the dust removal efficiency in the filter decreases, and the amount of external air introduced decreases and ventilation performance decreases.

The present invention has been made in view of the above points, and an object thereof is to change the control form of the air conditioning capacity so that the air conditioning capacity of each VAV unit can be properly maintained and Even in a low VAV unit, the air flow rate is increased to increase the dust removal efficiency and ventilation performance of the filter to improve and maintain comfort.

[0007]

In order to achieve this object, it is noted that in the invention of claim 1, the air conditioning capacity of each VAV unit is involved not only in the blown air volume of the conditioned air but also in its temperature. However, this supply air temperature is corrected according to the capacity of the VAV unit for which maximum capacity is required.

That is, according to the present invention, as shown in FIG. 1, the supply air generating means (4) for generating the conditioned air adjusted to the target temperature and the conditioned air generated by this supply air generating means (4). An indoor unit (1) having a blower (5) for blowing air is provided, and the indoor unit (1) is provided in each of a plurality of zones (Z), (Z), ... A plurality of VAVs that are branched and connected via a duct (18), set a target air volume for each zone (Z), adjust the blowout air volume to reach the target air volume, and blow out the conditioned air from the blower (5). Unit (31),
The precondition is an air conditioner including (31) ,.

Then, for this air conditioner, from the plurality of VAV units (31), (31), ...
VAV unit (3
1) for detecting the air conditioning capacity and the output of the air conditioning capacity detecting means (42), the air conditioning load of the VAV unit (31) detected by the air conditioning capacity detecting means (42) is from the maximum value. When the VAV unit (31) blows, the amount of air blown out from the VAV unit (31) must be reduced.
To increase the set value to achieve the required air conditioning capacity
And a supply air temperature correction means (43) for correcting the target temperature of the conditioned air by the supply air generation means (4).

According to the second aspect of the present invention, the set value of the blown air volume in the air supply temperature correction means (43) is the maximum air volume in the VAV unit (31).

[0011]

According to the first aspect of the invention, when the VAV unit (31) for which the maximum air conditioning capacity is required drops from the maximum value of the air conditioning capacity, the blown air volume is changed to the VAV unit (3).
Increase to the set value to achieve the required air conditioning capacity in 1)
As described above , the conditioned air target temperature in the supply air generation means (4) is shifted. Therefore, the VAV unit (31)
With the air-conditioning capacity according to, the original target value is maintained, and the amount of blown air can be increased by the amount by which the temperature of the conditioned air is shifted. Due to this increase in the blown air volume, even in the other VAV unit (31) having a small required capacity, the air volume is kept relatively large and the decrease in the air volume is reduced, and the dust removal efficiency and the ventilation performance of the filter are not significantly reduced. The comfort of the air conditioner can be improved.

According to the invention of claim 2, the VAV unit is provided.
The set value for achieving the required air conditioning capacity in (31) is the highest.
This is a large value, and the amount of air blown from the VAV unit (31) is
So that the the maximum value, the target temperature of the conditioned air is corrected, the correction temperature of the conditioned air can be shifted to the maximum, correspondingly, further increasing the airflow volume, more reliably the effect Can be obtained.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.

FIG. 2 shows the overall construction of the air conditioner according to the embodiment of the present invention. This air conditioner basically has 1
One indoor unit (1) and three VAV units (3
1), (31),... The downstream ends of the 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) is open to the outside. Inlet (1
0), and an outside air intake damper (11) is provided on the way. On the other hand, the upstream end of the inside air intake duct (9) is connected to an inside air inlet (12) that opens at a predetermined position in the room, and a return air blower (13) and an inside air intake damper (14) are provided on the way. They are arranged in order from the side. An upstream end of an exhaust duct (15) is branched and connected to a duct (9) downstream of the return air blower (13) and upstream of the inside air intake damper (14) via a switching damper (16). The downstream end of the exhaust duct (15) has an exhaust port (17) that opens outside the room.
It is connected to the. Then, the outside air intake damper (11) is closed, the inside air intake damper (14) is opened, and the switching damper (16) is closed so that the inside air intake duct (9) is disconnected from the exhaust duct (15). At the time of switching, the inside air (return air) taken in from the inside air intake (12) is sucked into the housing (2) through the inside air intake duct (9) by the return air blower (13). To cool or heat the room. On the other hand, the outside air intake damper (11) is opened, and the inside air intake damper (14) is closed,
Further, when the switching damper (16) is switched so that the inside air intake duct (9) downstream of the return air blower (13) communicates with the exhaust duct (15), the inside air is blown by the return air blower (13). The inside air taken in through the intake (12) is discharged outside through the exhaust port (17), and the outside air intake (10).
The outside air taken in from outside is sucked into the housing (2) through the outside air intake duct (8) to ventilate the room while cooling and heating the room.

A filter (3), an indoor heat exchanger (4), and a blower (5) driven by a motor (not shown) are arranged in the housing (2). The indoor side heat exchanger (4) is connected to an outdoor unit (not shown) via a refrigerant pipe (6), and after filtering air sucked into the housing (2) by a filter (3), heat is applied to the heat exchanger (4). Heat is exchanged in the exchanger (4) to generate conditioned air (air supply), and the conditioned air is blown out of the housing (2) by the blower (5).

The upstream end of a blow-out duct (18) is connected to the blower outlet (5) of the indoor unit (1), and the downstream end of this duct (18) is divided into three branch ducts (18).
a), (18a),... and the outlets (19), (1) arranged in different zones (Z), (Z),.
9), and the VAV units (31) are arranged in the respective branch ducts (18a). Each VAV unit (31) sets a target air volume based on the room temperature and the set temperature in each zone (Z), adjusts the blown air volume so that the actual air volume becomes the target air volume, and the blower (5 ) From the conditioned air. That is, as shown in FIG. 3, the VAV unit (31) includes a room temperature detection thermostat (32) for detecting the actual room temperature in each zone (Z) and a set temperature (Ts) of the room temperature.
) Setting room temperature setting section (33) and the outlet (19)
Air volume adjustment damper (3
4), the target air volume is calculated based on the room temperature detected by the room temperature detection thermostat (32) and the temperature (Ts) set by the room temperature setting unit (33). A target air volume calculator (35) for controlling the opening of the adjustment damper (34) is provided. When the above target air volume is calculated, for example, during cooling, as shown in FIG. 4, the room temperature is compared with the set temperature (Ts), and the room temperature is lower than the set temperature (Ts) by 0.4 ° C. or more. Sometimes
The target air volume is fixed at 30% of the rated air volume (100%), and the target air volume is 30% according to the temperature difference between the room temperature and the set temperature (Ts) between -0.4 ° C and + 1 ° C. From 100
%, The target air volume is fixed to 100% when the temperature difference is + 1 ° C or more.

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

The opening of the flow rate adjusting valve (7) is controlled by the control unit (41). As shown in FIG. 3, the control unit (41) includes a supply air temperature thermostat (50) for detecting the temperature of the conditioned air (supply air) blown from the blower (5), and each VAV unit (31). The target air flow rate calculation units (35) are connected to each other, and in the control unit (41), air conditioning is performed based on the signals of the supply air temperature thermostat (50) and the target air flow rate calculation unit (35) of each VAV unit (31). The target value of the air temperature, that is, the target air supply temperature (T1t) is calculated, and the opening of the flow rate adjusting valve (7) is feedback-controlled so that the conditioned air temperature becomes the target temperature (T1t).

Here, the control procedure performed by the control unit (41) during cooling of the air conditioner will be specifically described with reference to FIG. First, in step S1 after the start, it is determined whether or not the timer has timed out. This timer counts a fixed period and counts 5 minutes as described later. If it is determined that the time is up, the process proceeds to step S2 and the three VAVs are
The maximum value is selected from the temperature differences (δT1) to (δT3) between the room temperature and the set temperature in the units (31), (31), ... That is,
In this step S2, the maximum air conditioning capacity of the three VAV units (31), (31), ... Is required based on the temperature difference (δT1) to (δT3) between the room temperature and the set temperature. Detect one VAV unit (31).

In the next step S3, it is determined whether or not the selected maximum temperature difference (δT) is a fixed value (= 1.5) or more. If this determination is YES with δT ≧ 1.5,
Since a large cooling capacity is required for the detected VAV unit (31), the target temperature (T1t) of the conditioned air is set to the detected VAV unit (3) in step S4.
After setting the initial value (T1MAX) (= 13 ° C., for example) which is a temperature at which the air conditioning capacity (cooling capacity) becomes the rated capacity when 1) is the rated air volume, the process proceeds to step S9.

The determination made in step S3 is δT <1.5.
When the result is NO, that is, when the cooling load in the VAV unit (31) for which the maximum cooling load is required has dropped from the maximum load, the routine proceeds to step S5, where the maximum temperature difference (δT) is the first set value ( = 1.0 ° C) or more, and when this determination is YES with δT ≧ 1.0,
In step S6, the target temperature (T1t) of the conditioned air is lowered by 0.5 ° C from the target temperature (T1t) up to then (T1t-
After 0.5) ° C. and shifting to a temperature at which the cooling capacity increases, the process proceeds to step S9.

The determination in step S5 is δT <
When the answer is NO in step S7, it is determined in step S7 whether or not the maximum temperature difference (δT) is less than or equal to the second set value (= 0.5 ° C). If YES, in step S8 the target temperature (T1t) of the conditioned air is
The target temperature (T1t) up to then is increased by 0.5 ° C to (T1t + 0.5) ° C, and the temperature is reset to a temperature at which the cooling capacity is reduced, and then the process proceeds to step S9.

In step S9, the timer is set to 5 minutes. After that, the timer is counted in step S10, and the process returns to the first step S1. This step S
If it is determined 1 in step 1 that the time has not yet expired, the process immediately proceeds to step S10 and waits for the time to elapse.

In this embodiment, the three VAV units (31), (3
VA requiring the maximum air conditioning capacity among 1), ...
Air-conditioning capacity detecting means (4) for detecting the V unit (31)
2) is configured.

Further, in steps S3, S7 and S8 ,
Receiving the output of the air conditioning capacity detecting means (42), when the air conditioning load of the VAV unit detected by the detecting means (42) (31) is lowered from the maximum value, airflow volume in the VAV unit (31) is, Required for VAV unit (31)
Maximum value as a set value to achieve the required air conditioning capacity
A supply temperature correction means (43) for correcting the target temperature (T1t) of the conditioned air by the heat exchanger (4) from the initial value (T1MAX) to the correction value ( T1MAX + 0.5 ) so as to increase to (100%). ) Is configured.

Therefore, in the above embodiment, when the air conditioner is cooled, the control unit (41)
The target temperature (T1t) of the conditioned air generated by the heat exchanger (4) is calculated, and the flow control valve is adjusted so that the conditioned air temperature detected by the supply air temperature thermostat (50) becomes the target temperature (T1t). The opening of (7) is feedback-controlled. At this time, the VAV unit (31) for which the maximum capacity is required is selected from the VAV units (31), (31), ... And the air conditioning capacity of this VAV unit (31) is changed from the maximum value (100%). When lowered, the target value of the conditioned air temperature (T1T) from the initial value (T1MAX), blowing air volume of at the VAV unit (31) is assumed to have increased to the maximum value
In that case, the temperature is shifted to a temperature (T1MAX + 0.5) at which the required air conditioning capacity is achieved in the VAV unit (31). Then, the target value (T1t) of the conditioned air temperature is reviewed every 5 minutes set by the timer, and the target value is reset to the initial value (T1MAX) according to the increase change of the cooling load.

Therefore, the cooling loads of the three zones (Z), (Z), ...
%, 50%, 30%, the conventional air-conditioning air temperature is 100%, so zones (Z), (Z), ...
The air flow rate and cooling capacity are 80% and 50%, respectively.
%, 30%, whereas in this embodiment the temperature of the conditioned air is 80%, the zones (Z), (Z),
The air volume of ... is 100%, 62.5% {= (100
/ 80) × 50}, 37.5% {= (100/80) ×
30}, the cooling capacity is 80%, 50%, 3 respectively
0%. As a result, only the air volume increases without changing the cooling capacity as compared with the conventional case.

Due to such an increase in the blown air volume, even in the VAV unit (31) having a small required capacity, the decrease in the air volume is suppressed to a minimum, and the dust removal efficiency and the ventilation performance of the filter (3) are prevented from being greatly reduced. Therefore, the comfort of the air conditioner can be improved.

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

The control of the supply air temperature is the same as in the case of the direct expansion heat exchanger, and the capacity is controlled by the flow control valve and the capacity of the compressor. 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.

[0031]

As described above, according to the inventions of claims 1 and 2, an indoor unit for blowing conditioned air at a predetermined temperature and an indoor unit connected to each of the indoor units through ducts, and each zone in the room. In contrast to an air conditioner equipped with a plurality of VAV units that adjust the amount of blown air to blow out the conditioned air from the indoor units, the unit requiring the maximum air conditioning load among the VAV units is When it drops, the amount of air blown out from the VAV unit
Increase to set value to achieve required air conditioning capacity
By adjusting the temperature of the conditioned air,
By increasing the blown air volume while maintaining the air conditioning capacity of each VAV unit, it is possible to suppress a decrease in the air volume of a VAV unit with a small required capacity, and to suppress dust removal efficiency and ventilation performance of the air conditioner and improve comfort. Can be achieved.

In particular, according to the second aspect of the invention, the amount of air blown out from the VAV unit for which the maximum air conditioning capacity is required is
In order to achieve the necessary air conditioning capacity with the VAV unit,
Since the conditioned air temperature is corrected so as to have a large value, it is possible to suppress the decrease in the air volume of the blown air volume to the minimum and obtain the above-mentioned effect more reliably.

[Brief description of the drawings]

FIG. 1 is a diagram showing an 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 illustrating a configuration of a control system.

FIG. 4 is a characteristic diagram for calculating a target air volume in each VAV unit.

FIG. 5 is a flowchart showing a control procedure in a control unit.

[Explanation of symbols]

 (1) ... Indoor unit (4) ... Heat exchanger (air supply generating means) (5) ... Blower (18) ... Blowout duct (31) ... VAV unit (34) ... Air volume adjustment damper (41) ... Control unit ( 42) ... Air-conditioning capacity detection means (43) ... Supply air temperature correction means (50) ... Supply air temperature thermostat (Z) ... Zone

Claims (2)

(57) [Claims] 1. A built-in air supply generating means (4) for generating conditioned air adjusted to a target temperature, and a blower (5) for blowing the conditioned air generated by the air supply generating means (4). The indoor unit (1) is arranged in each of the plurality of zones (Z), (Z), ... In the room, and the duct (1) is provided in the indoor unit (1).
A plurality of VAs that are branched and connected via 8), set a target air volume for each zone (Z), adjust the blowout air volume to reach the target air volume, and blow out the conditioned air from the blower (5).
In an air conditioner provided with V units (31), (31), ..., Of the plurality of VAV units (31), (31), ... ) Is detected, and the VAV unit (3) detected by the air conditioning capacity detecting means (42) receives the outputs of the air conditioning capacity detecting means (42).
When the air conditioning load of 1) drops from the maximum value, the VAV
The blowing air volume in the unit (31) is equal to the VAV unit (3
Increase to the set value to achieve the required air conditioning capacity in 1)
In this way, the air conditioner is provided with the supply air temperature correction means (43) for correcting the target temperature of the conditioned air by the supply air generation means (4). 2. The air conditioner according to claim 1, wherein the set value of the blown air volume in the air supply temperature correction means (43) is the maximum air volume in the VAV unit (31).