JP2000304333A - Vav control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To return the room temperature quickly within the allowable range of a set level even when it deviates from the allowable range temporarily due to disturbance. SOLUTION: A VAV control unit 10' (10'-1,..., 10'-n) calculates the air conditioning load Q at current time according to a formula; Q=L.c.Δt+ΔQ, where Δt=ts-t and ΔQ=C.(Δpv/T). In the formula, Q; conditioning load, L; VAV air supply, c; specific heat of air, ΔQ; penalty heat quantity, Δt; supply air temperature difference, ts; supply air temperature, t; room temperature, C; thermal capacity of control space, Δpv; room temperature control difference, T; response time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a supply of blow-off air from an air conditioner, and the amount of air blown to the first to N-th controlled areas in accordance with the load situation. The present invention relates to a VAV control system having first to N-th variable air supply amount adjusting means (VAV control units) for controlling each of them.

[0002]

2. Description of the Related Art Conventionally, in a large-scale building, when air is supplied from an air conditioner to each part through an air supply duct, each air supply outlet of each air conditioning target portion (controlled area) is provided. A variable air supply amount adjustment unit (VAV unit) is provided, and the amount of air blown from the VAV unit is controlled by the VAV control unit according to the load condition of the controlled area. That is, the amount of air blown to the controlled area is controlled by adjusting the damper opening of the VAV unit by the VAV control unit.

In this VAV control system, the temperature of the supply air from the air conditioner (the temperature of the air to be blown) is controlled based on the control status indicating the load condition (indoor condition) of the controlled area from each VAV control unit. ing. As shown in FIG. 2A, the VAV control unit sets the control status as "control temperature" according to the current indoor temperature and the current air flow to the controlled area (VAV air flow) as shown in FIG. One of “insufficient”, “appropriate warming”, “heating”, “optimal”, and “overheating” is determined and sent to the control device. FIG. 2B shows a case where the blown air temperature <the indoor temperature.
As shown in the table, according to the current indoor temperature and the current air flow rate (VAV air flow) to the controlled area, the control status is “insufficient”, “appropriate cooling”, “cooling”, “optimal”, “supercooling”. "
Is determined and sent to the control device.

[0004] The control device is a "supercooled"("superheated") VA.
If there is even one V, the blowing temperature is greatly increased (down). In the case where the “supercooled” VAV and the “superheated” VAV are mixed, the up / down of the blowing temperature is determined by majority decision. If there is a VAV of “appropriate cooling” or “cooling” (“appropriate warming” or “heating”), the blowing temperature is slightly increased (down). If all the VAVs are “optimal”, the air temperature is maintained at the current level.

However, according to such a conventional VAV control system, the "supercooled" VAV and the "superheated"
In the case where AV and AV are mixed, since the up / down of the blast temperature is determined by majority decision, the blast temperature may not be determined as an appropriate value. For example, V
If the number of AV> the number of VAVs of “overheated”, but the total degree of VAV of “supercooled” <the total degree of VAV of “superheated”, that is, a little “supercooled” If there are several VAVs and one large "overheated" VAV, and the total is "overheated", the majority system will increase the ventilation temperature because there are many "supercooled" units. Would.

FIG. 3 shows an example. In this figure, VA
V ~ is "supercooled" of about "-1", VAV is "+"
It is about 5 "overheating. In this case, in the majority decision method, it is determined that the supercooling is 3: 1. However, in actuality, the total degree of “supercooled” VAV is “−3”,
The total degree of VAV of "overheating" is "+5",
In total, it is “overheated”. In this case, in order to set the blowing temperature to an appropriate value, the blowing temperature must be decreased, but the temperature is increased. As described above, the conventional technique cannot not only cope with the above contradictory request, but also can show only the control direction even if there is no contradiction, and can determine a clear set value of the blowing temperature. Can not.

Therefore, the present applicant has filed a Japanese Patent Application No. Hei 8-3171.
As No. 0 (Japanese Patent Application Laid-Open No. 9-22943), a VAV control system that can always keep the blowing air temperature at an appropriate value has been proposed. FIG. 1 is an instrumentation diagram of the VAV control system. In FIG. 1, reference numeral 1 denotes an air conditioner, a cooling coil 3 to which cold water CW is supplied via an electric valve 2, a heating coil 5 to which hot water HW is supplied via an electric valve 4, and a blower 6.
It consists of. Inverter 6 in air conditioner 1
The operation of the b, the motor-operated valve 2 and the motor-operated valve 4 is controlled by the control device 7, and air supplied from the fan 6 a in the air conditioner 1 is supplied to the controlled areas 9-1 to 9-via the air supply duct 8. n. Controlled area 9-1
9-n is a temperature sensor T1 for detecting the room temperature for each area.
To Tn, and the detected temperatures PV from the temperature sensors T1 to Tn are individually supplied to the locally provided VAV control units 10-1 to 10-n.

[0008] VAV control units 10-1 to 10-1
0-n indicates the detected temperature PV and the set temperature S given to each individual.
The required air volume to the controlled areas 9-1 to 9-n is calculated based on the deviation from P and the blast temperature given by the control device 7, and is returned to the control device 7 while the required air volume is secured. VAV units 11-1 to 11-
n of the dampers 12-1 to 12-n are determined by the wind speed sensor 1.
The control is performed while observing the detection powers (actual air volume) of 3-1 to 13-n.

The VAV control unit 10-
1 to 10-n determines the allowable range of the blast temperature to the controlled areas 9-1 to 9-n capable of processing the air-conditioning load Q at the current time as the allowable blast temperature range, and determines the obtained allowable blast temperature range as a control device. It also has a function to send to 7. The control device 7
The permissible air temperature range sent from the AV control units 10-1 to 10-n is set to a weight coefficient Wn (0 <Wn <1:
(Wn = 1) is converted into the vote rate range, and the temperature of the air blown from the air conditioner 1 is determined based on the vote rate range.

[How to determine allowable air temperature range in VAV control unit] VAV control unit 10
(10-1 to 10-n) indicates an allowable range (allowable air temperature range) of the air temperature ts to the controlled area 9 (9-1 to 9-n) which can process the air conditioning load Q at the current time, and tsmin. ≤t
It is determined as s ≦ tsmax. Where tsmin, tsmax
Tsmin = t + Δtmax, tsmax in the cooling mode
= T + Δtmin, and in the heating mode, tsmin =
It is obtained as t + Δtmin, tsmax = t + Δtmax.

Here, t is the air temperature (room temperature) in the controlled area 9, Δtmin is the minimum air temperature difference, Δtmax is the maximum air temperature difference, and the cooling / heating mode is “current time air temperature tsreal”.
−Indoor temperature set value tsp ”, where positive is a heating mode and negative is a cooling mode. In addition, the minimum air temperature difference Δt
min is obtained as Δtmin = Q / (Lmax · c), and the maximum air temperature difference Δtmax is obtained as Δtmax = Q / (Lmin · c). Here, Lmax is the maximum airflow of VAV (design value), Lmin is the minimum airflow of VAV (design value), c is the specific heat of air [kJ / m ³ K (Kcal / m ³ ° C)], and Q is the current Is the time air conditioning load [KW (kcal / h)], the air volume of the VAV at the current time is L [m ³ / s (m ³ / h)], and the air temperature difference at the current time is Δt (Δt = tsreal-t). ), It is obtained as Q = L · c · Δt by the calculation formula of the sensible heat air conditioning load.

That is, the maximum air flow of the VAV (design value)
Then, the minimum air temperature difference Δtmin [Δtmin = Q / (Lmax
・ C)], and the minimum air flow (design value) of VAV is
Maximum air temperature difference Δtmax [Δtmax = Q / (Lmin ·
c)], and there is an allowable ventilation temperature range between the maximum ventilation temperature difference Δtmax and the minimum ventilation temperature difference Δtmin. In the cooling mode, the permissible air temperature range is tsmin = t + Δtmax and tsmax = t + in the cooling mode.
In addition to Δtmin, it can be obtained as tsmin ≦ ts ≦ tsmax. In the heating mode, tsmin =
t + Δtmin, tsmax = t + Δtmax, and tsm
in ≦ ts ≦ tsmax.

[Conversion to vote rate range by controller] VA
The permissible air temperature range determined in the V control units 10-1 to 10-n is sent to the control device 7. The control device 7 includes VAV control units 10-1 to 10-1.
The allowable air temperature range sent from 0-n is determined by a weighting coefficient Wn predetermined for each VAV control unit.
(0 <Wn <1: ΣWn = 1). In this case, the weight coefficient Wn is determined by the ratio of the air conditioning area at the VAV end (air conditioning area at the VAV end /
The air-conditioning area of the entire system), the importance of the VAV terminal air-conditioning region, or the load ratio (air-conditioning load of the VAV terminal / air-conditioning load of all systems) and the importance of the VAV terminal air-conditioning region are determined. The sum of the weight coefficients Wn of all the systems is 1.

For example, assume that n = 4 in FIG. That is, the VAV control units 10-1 to 10-1
10-4 exists and the VAV control unit 10-
1 (hereinafter referred to as VAV-1 #), the allowable air temperature range is 20 ° C. ≦ ts ≦ 24 ° C., and the VAV control unit 1
The allowable air temperature range of 0-2 (hereinafter, referred to as VAV-2 #) is 18 ° C. ≦ ts ≦ 23 ° C., and the allowable air temperature range of the VAV control unit 10-3 (hereinafter, VAV-3 #) is 17 °. ° C ≦ ts ≦ 21 ° C., the allowable air temperature range of the VAV control unit 10-4 (hereinafter referred to as VAV-4 #) is 18 ° C. ≦ ts ≦ 22 ° C., and the weight coefficient W1 of VAV-1 # is W1 = 0. 2. Weight coefficient W of VAV-2 #
2 is W2 = 0.3, and the weight coefficient W3 of VAV-3 # is W3.
= 0.3, and the weight coefficient W4 of VAV-4 # is W4 = 0.2
And

In this case, as shown in FIG. 4, the control device 7 sets an allowable air temperature range from VAV-1 # to 20 ° C. ≦ ts.
≦ 24 ° C. is converted into a vote rate range S1 in which the weight coefficient W1 = 0.2 (20%) is used as the vote rate. VAV-
Allowable air temperature range 18 ° C ≦ ts ≦ 23 ° C from 2 #,
The weight coefficient W2 = 0.3 (30%) is converted into a vote rate range S2 having the vote rate. Also, the allowable air temperature range from VAV-3 # of 17 ° C. ≦ ts ≦ 21 ° C. is set as the weight coefficient W3.
= 0.3 (30%) as a vote rate range S3
Convert to Further, the allowable ventilation temperature range from VAV-4 # of 18 ° C. ≦ ts ≦ 22 ° C. is set as the weight coefficient W4 = 0.2 (2
0%) is converted to a vote rate range S4 having that vote rate.

[Method of Determining Ventilation Temperature in Control Device] FIG. 4
As can be understood from FIG.
It has a common allowable blast temperature range of s ≦ 21 ° C. The total vote rate in this common allowable air temperature range reaches 100%. This means that VAV-1 # to # 4 # can process the air-conditioning load at the current time, regardless of the supply air temperature, in this common allowable ventilation temperature range. Therefore, the center of the maximum allowable blowing temperature range where the total vote rate is the maximum is determined as the blowing temperature. In the example of FIG. 4, the total vote rate is 1
The center of the permissible blast temperature range of 00%, ie 20 ° C.
20.5 ° C., which is the center of ≦ ts ≦ 21 ° C., is determined as the blowing temperature.

[0017]

In the VAV control system proposed by the present applicant, on the assumption that the room temperature t falls within the allowable range of the set value, the air-conditioning load Q at the current time is set for each VAV control unit 10. Is given by Q = L · c · Δt
And the allowable air temperature range is calculated based on the calculated air conditioning load Q. However, in an actual system, there is a case where the room temperature t temporarily deviates from the allowable range of the set value due to disturbance. When the room temperature t deviates from the allowable range of the set value, the room temperature t is stabilized there.
There is a problem that cannot be returned to the allowable range.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to reduce the room temperature to the set value even if the room temperature temporarily deviates from the allowable range of the set value due to disturbance. VA that can quickly return to an acceptable range
V control system.

[0019]

In order to achieve the above object, the present invention relates to the above-mentioned VAV control system, wherein the air-conditioning load Q at the current time is set for each of the first to N-th variable air supply amount adjusting means. , Δt = ts−t, ΔQ = C · (Δpv / T)
And is obtained by the following equation (1). Q = L · c · Δt + ΔQ (1) where Q: air conditioning load, L: VAV air flow, c: specific heat of air, ΔQ: penalty heat, Δt: air temperature difference, ts:
Blast temperature, t: room temperature, C: heat capacity of control space, Δpv:
Room temperature control deviation, T: response time. According to the present invention, the air-conditioning load Q is determined in consideration of the penalty heat amount ΔQ according to the degree of deviation of the set value of the room temperature t from the allowable range.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments. In this embodiment, the system configuration is the same as the conventional one shown in FIG.
AV control unit 10 (10-1 to 10-n)
Is different in the calculation method of the air-conditioning load Q. In this case, the VAV control unit is 10 '(10'-1 to 1').
0'-n) to distinguish them from the conventional VAV control unit.

[Calculation of Air-Conditioning Load Q in VAV Control Unit] In the VAV control unit 10 ', the air-conditioning load Q at the current time is Δt = ts-t, ΔQ = C
・ (Δpv / T), and is calculated by the following equation (1). Q = L · c · Δt + ΔQ (1) where Q: air conditioning load, L: VAV air flow, c: specific heat of air, ΔQ: penalty heat, Δt: air temperature difference, ts:
Blast temperature, t: room temperature, C: heat capacity of control space, Δpv:
Room temperature control deviation, T: response time.

When the room temperature t is within the allowable range of the set value, the penalty calorific value ΔQ is zero. L · c · Δt at that time is considered to be the current air conditioning load. When the set values of the room temperature for cooling, heating and heating are different, the allowable range of the set value of the room temperature t is −ε.
+ Tsp, h ≦ t ≦ ε + tsp, c. here,
ε is the control tolerance, tsp, c is the cooling room temperature set value, ts
p and h are heating room temperature set values.

The penalty heat amount ΔQ is a required sensible heat amount for returning the set value to the allowable range when the room temperature t exceeds the allowable range of the set value, and is calculated as ΔQ = C · (Δpv / T). The response time T is a time required for the room temperature t to return to within the allowable range of the set value. If the measured value is used for the VAV air supply amount L and the measured values are used for Δt and Δpv, the air conditioning load Q at the current time can be calculated by the above equation (1).

In this case, the air-conditioning load Q at the current time is obtained in consideration of the penalty calorific value ΔQ according to the degree of deviation of the set value of the room temperature t from the allowable range. , The room temperature t can be promptly returned to the allowable range of the set value.

The VAV control unit 10 '
The method of obtaining the allowable air temperature range in the above and the conversion to the vote rate range in the control device 7 are the same as those in the conventional method, and therefore the description thereof is omitted here.

[At the time of start-up of the air conditioner 1] Q = L · c ·
In the conventional method of obtaining the air conditioning load Q as Δt, the air conditioner 1
When the air rises, the air flow from the air conditioner 1 is zero (VAV
Since the blowing amount L is zero), the air-conditioning load Q becomes zero and the allowable blowing temperature range cannot be calculated. Further, even if the air conditioner 1 starts to blow air, if the room temperature t deviates from the allowable range of the set value, it is stabilized there and cannot enter the allowable range of the set value. For this reason, the air conditioner 1 is in a normal operation state (a state in which the fan rotates and cold or hot water is supplied to the air conditioner), and the control of the blowing temperature can be started until the room temperature t falls within the allowable range of the set value. The start of control was bad.

On the other hand, in the present embodiment, when the air conditioner 1 starts up, the air conditioning load Q does not become zero based on the penalty heat amount ΔQ even if the VAV air blowing amount L is zero, and the air blowing temperature allowable range is calculated. can do. Further, when the air conditioner 1 starts blowing, even if the room temperature t is out of the allowable range of the set value, the room temperature t can be quickly returned to the allowable range of the set value by the penalty calorific value ΔQ. Thereby, it becomes possible to start the control of the blowing air temperature almost simultaneously with the start-up of the air conditioner 1, and it is possible to improve the start-up of the control.

In the above description, when calculating the air-conditioning load Q at the current time, Δt = ts
-T was used. In this case, if a disturbance such as humidification that changes the blowing temperature ts enters, it is immediately affected, and it takes time to escape from the adverse effect. The change in the blast temperature ts due to the disturbance is obtained by using the blast temperature set value ts, sp instead of ts, that is, Δt = t
It is possible to address this by using Δt = ts, sp−t instead of st. In this case, since the blast temperature control responds quickly, the blast temperature ts
Is removed in a short time.

[0029]

As is apparent from the above description, according to the present invention, the air-conditioning load Q at the current time is obtained as Q = L.c..DELTA.t + .DELTA.Q for each of the first to N-th variable air supply amount adjusting means. Therefore, the air-conditioning load Q is determined by taking into account the amount of penalty heat ΔQ corresponding to the degree of deviation from the allowable range of the set value of the room temperature t, and the room temperature temporarily reduces the allowable range of the set value due to disturbance. Even if it deviates, the room temperature can be quickly returned to the allowable range of the set value.

[Brief description of the drawings]

FIG. 1 is an instrumentation diagram of a VAV control system proposed by the applicant and a VAV control system showing an embodiment of the present invention.

FIG. 2 is a diagram showing how a control status is determined in a conventional VAV control unit.

FIG. 3 is a diagram exemplifying the degree of VAV when the control status is “supercooled” and “superheated”;

FIG. 4 is a graph showing respective vote rate ranges of VAV-1 # to 4 # in a VAV control system proposed by the present applicant.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Air conditioner, 2, 4 ... Electric valve, 3 ... Cooling coil, 5 ... Heating coil, 6 ... Blower, 7 ... Control device, 9-1 to 9-n
... Controlled area, 10'-1 to 10'-n ... VAV control unit, 11-1 to 11-n ... VAV unit, 12-1 to 12-n ... Damper, 13-1 to 13-n
... wind speed sensors, 14-1 to 14-n ... opening degree sensors, T1
To Tn: temperature sensor, 23: display unit, S1 to S4: vote rate range.

Claims (2)

[Claims] A first air supply from an air conditioner is supplied.
First to N-th variable air supply amount adjusting means for individually controlling the air flow to each of the N-th controlled areas in accordance with the load status of the controlled area; Means for determining an allowable range of the blast temperature to the first to Nth controlled areas capable of processing the air-conditioning load Q at the current time every time as an allowable blast temperature range; And a blast temperature determining means for determining a blast temperature from the air conditioner based on an allowable blast temperature range of the variable air supply amount adjusting means.
In the AV control system, the air-conditioning load Q at the current time is calculated for each of the first to N-th variable air supply amount adjusting means by Δt = ts−t, ΔQ = C · (Δpv / T)
A VAV control system comprising an air-conditioning load calculating means determined by the following equation (1). Q = L · c · Δt + ΔQ (1) where Q: air conditioning load, L: VAV air flow, c: specific heat of air, ΔQ: penalty heat, Δt: air temperature difference, ts:
Blast temperature, t: room temperature, C: heat capacity of control space, Δpv:
Room temperature control deviation, T: response time. 2. The air-conditioning load calculating unit according to claim 1, wherein the air-conditioning load set value is ts, sp, and Δt = ts−t
VAV control system, wherein Δt = ts, sp−t is used instead of