WO2002066903A1 - Method and equipment for automatic determination of flow resistance in the distribution network of an air-conditioning system - Google Patents

Method and equipment for automatic determination of flow resistance in the distribution network of an air-conditioning system Download PDF

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Publication number
WO2002066903A1
WO2002066903A1 PCT/FI2002/000109 FI0200109W WO02066903A1 WO 2002066903 A1 WO2002066903 A1 WO 2002066903A1 FI 0200109 W FI0200109 W FI 0200109W WO 02066903 A1 WO02066903 A1 WO 02066903A1
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Prior art keywords
room
distribution network
calculation
airflow
duct
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PCT/FI2002/000109
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French (fr)
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WO2002066903A8 (en
Inventor
Risto Kosonen
Tapani Salo
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Halton Oy
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Publication of WO2002066903A1 publication Critical patent/WO2002066903A1/en
Publication of WO2002066903A8 publication Critical patent/WO2002066903A8/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/0001—Control or safety arrangements for ventilation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/70—Control systems characterised by their outputs; Constructional details thereof
    • F24F11/72—Control systems characterised by their outputs; Constructional details thereof for controlling the supply of treated air, e.g. its pressure
    • F24F11/74—Control systems characterised by their outputs; Constructional details thereof for controlling the supply of treated air, e.g. its pressure for controlling air flow rate or air velocity

Definitions

  • the invention concerns a method and equipment for automatic determination of flow resistances in the distribution network of an air-conditioning system.
  • a model-based system has been developed for management and control of airflows, in which system known flow models of the distribution system and its components are used for controlling the desired airflows.
  • the position of control elements controlling the volume airflows is determined centrally and simultaneously by information derived from the control unit of a controlling element located at the top hierarchy level.
  • the model parameters are first given initial values, which are corrected when required with the aid of checking measurements made in the field. Calibration of this model always calls for a manual checking measurement.
  • the present application proposes an improvement on the above-mentioned manual determination, that is, calibration, of flow resistances in a distribution network.
  • a certain chosen set of room and branch ducts is run up to a sufficient pressure level, whereby the uncertainty in measurement is small.
  • the developed method checks the airflows automatically.
  • calibrating in state-of-the-art systems for example, in a system according to the applicant's earlier FI Patent Application 890170, this is already done entirely manually at the time when the system is delivered. This has meant that each room airflow into the room or out of the room has been measured separately, and the control units and their setting values have been changed separately for each room.
  • the present application aims at disposing with the said manual calibration and to achieve a solution, wherein the correct resistance coefficients for each distribution network/control equipment are determined in one go, and thus the correct and desired airflows into the rooms/out of the room spaces are also obtained as the final results after the determination.
  • the invention concerns a method and equipment for automatic setting of the desired airflows in a model-based air-conditioning system.
  • the air-conditioning system includes one or more air-conditioning units P to achieve the desired airflows and one or more distribution networks to conduct the airflows into the desired room spaces Rl, R2, ... or such and/or out of the room spaces Rl, R2, ... or such.
  • this application uses a model-based system as presented, the model parameters of which can be calibrated automatically with the aid of airflow measurement in the room duct and measurement of the static pressure in the distribution network and also with the aid of a calculated distribution network model. Using the calibration method it is possible automatically to check the correctness of airflows, for example, at the system's reception stage, without any manual measuring work.
  • Figure 1 is a schematic view of an air-conditioning system according to the invention.
  • the system shown in the figure includes supply air ducts and exhaust air ducts.
  • the system includes zones, whereby the calculation of each zone is performed separately and the other parts of the system are closed during the calculation or they are set at minimum flow.
  • Figure 2 is a block diagram view of the method according to the invention for automatic determination of flow resistances in the distribution network of an air- conditioning system.
  • the air-conditioning system according to the invention shown in Figure 1 includes room and/or zone control units, airflow control equipment, such as dampers, for the airflow of different room ducts, an airflow measuring unit for the different room ducts, a branch duct pressure measuring unit, control equipment for the airflow of the whole air-conditioning unit, such as a blowing fan and its management/control equipment, data transmission buses t connecting the different pieces of equipment and a central processing unit (such as a PC) 200, wherein a calculating unit 100 and a distribution network model 150 are stored.
  • the system may include zone- and/or room-specific equipment needed for airflow management and/or zone- and/or room-specific equipment needed for exhaust airflow management.
  • the calibration calculation unit 100 used in calibration and the distribution network calculation model 150 are programmed and stored in a separate central processing unit 200, which includes memory and programming capacity.
  • the calculations performed by the calculation unit 100, that is, the calibrated flow resistances, are updated to the distribution network's calculation model 150.
  • the calculation model 150 corresponds with e.g. the state of the art, for example, with the system according to the earlier FI Patent Application 890170.
  • the calculation model of the distribution network controls the dampers in such a way that when the airflow into a room is changed, new setting values are given simultaneously to all dampers in the system, so that the desired room flow is implemented and the other room flows remain the same as before.
  • duct resistances ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇
  • Figure 1 shows a division of the air-conditioning system into parts for determination of resistances, that is, for the calibration.
  • the air-conditioning system according to the invention includes in each room duct a measurement indicator or such which observes the airflow rate.
  • each zone to be calculated includes a pressure indicator, with which the pressure level in each zone can be controlled/measured during the calibration.
  • the air-conditioning system according to the invention includes a distribution network model 150, wherein are programmed and stored the calculation formulas for the zones of each distribution network system and wherein are stored the resistance values for the distribution network, dampers or such in their opening positions, for the air terminal devices, such as the register, which resistance values are obtained through tabular books or various calculations.
  • the distribution network model 150 includes programming capacity, and the resistance parameters for the concerned model can be stored in the memory of distribution network model 150 and can be programmed in calculation formulas.
  • Each damper or other such device control- ling the airflow and the blowing device bringing about the airflow include a separate control unit controlling the settings of the damper/blowing fan, whereby the blowing fan can be controlled to produce a certain pressure in the distribution network and the dampers are fitted so that their opening can be set in accordance with the room requirements.
  • the central processing unit 200 includes a central calculation unit 100 according to the invention performing the calibration and a distribution network model 150 of the system.
  • the central processing unit 200 may be formed by e.g. a PC or other computer.
  • the calculation unit 100 includes the presented calibration formulas and initial parameters for the formulas, which perform calculation of the resistances ki, k 2 ... and which relate to the distribution network, the ducts proper, the dampers or corresponding air terminal devices.
  • FIG. 1 The blowing fan or air-conditioning unit is indicated by the symbol P! in the figure.
  • trunk duct Ni branch ducts Ui, U 2 ... branch off and these branch off further into room ducts Oi, O 2 , O 3 ...
  • O 3 includes a control device controlling the airflow, such as a damper or such
  • the central processing unit 200 of the equipment there is a data transmission connection along data transmission buses t with the devices Si, S 2 ... controlling the airflow, with their control motors or such, and correspondingly, with the device controlling the speed of rotation of blowing fan P or with the device or motor controlling the airflow of air-conditioning unit P.
  • the ducts on the supply side and exhaust side of rooms Ri, R 2 ... are marked with the same indices.
  • the method according to the invention may be implemented for the supply airflow into its sectors Ai, Bi, Ci ... or on the exhaust air side into sectors Ai, Bi, Ci... of the exhaust airflow.
  • the pressure indicator for example, in branch duct Ui, is marked as PE.
  • each room duct Oi, O 2 ... near the control device controlling the airflow, such as a damper Si, S 2 ... includes in the room duct Oi, O 2 ... an indicator ei, e 2 ... or such measuring the airflow rate [1/s].
  • a pressure indicator PE measuring the distribution network pressure is preferably located in the branch duct Ui, U ... of each sector Ai, Bi... Blowing fan P is adapted to produce an airflow into each sector Ai, Ci...
  • a similar arrangement is on the exhaust side, whereby the blowing fan produces an exhaust airflow from each room space Ri, R 2 ...
  • the exhaust side correspondingly also includes room ducts Oi, O 2 ..., which are joined to the branch ducts Ui, U 2 ..., which are further joined to trunk duct Ni, wherein the exhaust fan P is installed.
  • Each control device Si, S 2 ... such as a damper, includes associated with itself as a control unit a motor or such, to which a data transmission bus t leads from central processing unit 200 in order to control the concerned damper.
  • a data transmission bus t to the central processing unit to transmit measurement data to central processing unit 200.
  • the central processing unit 200 associated with itself includes a calculation unit 100 performing calculation to determine the resistances ki, k ...
  • a distribution network calculation model 150 is installed/stored in central processing unit 200 and the distribution network as formulas and parameters, such as resistance coefficients.
  • the method and equipment according to the invention are used. In this application, the determination of the resistance ki, k 2 ... to correspond with the reality is also called calibration.
  • Room ducts Oi, O 2 ... are discussed in the following. When discussing branch ducts in the following, those ducts Ui, U 2 ... are meant, with which room ducts Oi, O 2 ... are joined.
  • the branch ducts Ui, Hi... are further joined to trunk duct Ni.
  • Each sector Ai, Bi, Ci ... is defined in such a way that it includes a branch duct and the joining room ducts.
  • Central processing unit 200 may be a PC or other computer.
  • the present application presents a method and equipment for performing automatic calibration in an air-conditioning system.
  • the air- conditioning system includes a blowing fan, a frunk duct and branch ducts, which branch off further into room ducts.
  • the system may further for exhaust air from each room include room ducts joining the branch duct, which is joined further to the trunk duct.
  • Each room duct includes an airflow control device to control the airflow rate.
  • the air-conditioning system may also include just a trunk duct, a branch duct and room ducts, through which fresh air is supplied, or the system may also include just the exhaust ducts, as described above. From the trunk duct supply airflows are branched off into several branch ducts and further from the branch ducts into the room ducts. In a special case the distribution network may lack the branch duct level, and the room ducts Oi, O 2 ... branch off directly from the trunk duct Ni.
  • the trunk duct Ni functions mainly in the same way as the branch duct Ui, U 2 ... presented in this application. There may be a similar a ⁇ angement also for the air exhaust or only for this.
  • the room ducts include a control device controlling the airflow, for example, a damper, to control the airflow rate into the room space/out of the room space.
  • a control device controlling the airflow for example, a damper
  • the airflow control devices, such as dampers or such, and the blowing fan include control devices to control the airflow control device and to control the blowing fan.
  • This application presents an automatic calibration system for an air-conditioning system.
  • a measuring device e.g. a measurement indicator
  • a measurement indicator is located to measure the pressure.
  • Starting of the automatic calibration takes place at each branch duct in such a way that the airflow connections with the remaining network are closed off and the blowing fan is operated to produce a certain pressure level.
  • All dampers of the concerned calibration area are set in a certain position. The resistance coefficients of the dampers are known, but the distribution network resistances are determined in the system based on certain tabular books and types of flow resistance structures.
  • the automatic calibration is carried out in accordance with the invention by using flow equations known as such and a loop method in the calculation.
  • the calculation formulas are stored in distribution network model 150, and in the calculation unit 100 performing calibration, that is, determination by calculating the flow resistances.
  • calibration takes place set-wise in such a way that the room ducts and branch ducts belonging to a certain calibration set are calibrated at a time. Calculation begins e.g. from the calibration set located nearest to the pressure indicator PE, and the calculation proceeds from the first calibration set first in the direction of airflow towards the branch duct end and finally from the first calibration set in a counter-current direction towards the blowing fan.
  • the blowing fan is run to produce a certain predetermined pressure value, which is measured by the pressure indicator PE or such from the branch duct.
  • the pressure indicator is set at a certain place in the branch duct. This place is ⁇ relevant as such. Calculation proceeds in such a way that co ⁇ ected duct resistances are obtained as the result of the calculation.
  • the calibration arrangement in question may also be performed similarly with the exhaust ducts.
  • the airflows of the branches are measured and they are compared with the airflows given by the calculation formulas, that is, by the model.
  • a new value is set for the room duct's resistance.
  • the said new value can be given by weighting the resistance calculated on the basis of measurements and the earlier value with a weighting coefficient.
  • the new room duct-specific airflows are measured.
  • new resistances based on measurement are calculated for the branch duct components.
  • a new value is given to the branch duct's resistance by weighting the value calculated on the basis of measurements and the earlier value with the set weighting coefficient.
  • the new resistance values of the branch duct components are set and the iteration calculation is repeated, until the room duct-specific airflows are sufficiently accurate.
  • resistances for the dampers of room ducts in their different control positions may be calculated with the above-mentioned method by utilising the distribution network resistances already calculated.
  • Figure 2 is a block diagram view of a method for determination of resistances.
  • the distribution network is thus divided into parts, through which a suitable airflow passes to achieve reliable measurements.
  • all dampers to be calibrated are set in control positions, where a sufficient flow resistance arises in them, and the other brancl-i/trunk dampers are closed.
  • calibration takes place set-wise in such a way that the room ducts and branch ducts belonging to a certain calibration set are always calibrated at a time.
  • the calculation is started e.g. from the calibration set located nearest to the pressure indicator PE, and the calculation proceeds manually from the first calibration set, first in the flow direction towards the branch duct end and finally from the first calibration set manually in a counter-current direction towards the blowing fan.
  • the chosen dampers to be calibrated are given setting values, on the basis of which a setting value is calculated for the trunk duct's static pressure using the system model.
  • the said static pressure is regulated by using the blowing fan.
  • the distribution network is divided into zones Ai, Bi, Ci ..., that is, into sectors, whereby each sector Ai, Bi, Ci ... includes a branch duct Ui, U 2 ... branched off from the trunk duct Ni and room ducts Oi, O 2 ... branched off from the branch duct and opening into the rooms.
  • the room ducts Oi, O 2 ... include flow-controlling control devices Si, S 2 ..., such as dampers, and measuring devices ei, e 2 ... indicating the airflow rate, such as measurement indicators. Calculation as regards distribution network resistances as well as damper resistances takes place zone-wise Ai, Bi, Ci..., so that each zone Ai, Bi, Ci ...
  • the distribution network calculation an iteration calculation method is used to determine the correct distribution network resistances, and the calculation/iteration is continued until the air rate indicated by the distribution network's calculation model is equal with sufficient exactitude to the measured air rate at a certain static pressure in the distribution network and at certain openings of the devices controlling the flow rate.
  • the calculation proceeds in such a way that the calculated distribution network resistances at the end of the iteration round function as a basis for the calculation in the following stage, when damper resistances are determined.
  • the calculation for dampers is quite the same. Hereby the dampers are set at a certain opening position. As regards resistances the dampers may be calculated in different opening positions, whereby a certain resistance curve is obtained for the dampers or such depending on the damper's opening position.
  • This example presents calculation of the room ducts of two rooms (Rl and R2) and of the branch duct between them and calibration of the model.
  • the damper is fully open.
  • FIG. 1 Diagram of distribution network
  • q v0 is 0 hereinafter, and it will not be present in the equations.
  • ⁇ p is the static pressure difference, magnitude to be measured [Pa] q v0 is the airflow in the branch duct after room Rl (known) [1/s] q v ⁇ is the airflow in room Rl [1/s] q v2 is the airflow in room R2 [1/s] k 23 is the resistance in the branch duct between the pressure indicator and room duct R2 k ⁇ 2 is the resistance in the branch duct between room ducts R2 and Rl ki is the resistance of room duct Rl : of damper (open), duct, air terminal device and T-branch k 2 is the resistance of room duct R2: of damper (open), duct, air terminal device and T-branch ⁇ h is the weighting coefficient (0...1), e.g. 0.3 ⁇ p is the weighting coefficient (0...1), e.g. 0.3 ⁇ is the maximum permissible e ⁇ or in the room duct's airflow
  • Subindices: i-1 is the calculated value or initial value of the previous iteration round i is the calculated provisional result of this iteration round i+1 is the final result of this iteration round, which is the initial value for the following round m is the measured result
  • Calculation step I presents an alternative way of calculating the airflow rate.
  • the distribution network model 150 stored in central processing unit 200 may be used, similar to the one presented e.g. in the applicant's FI Application 890170.
  • the pressure difference ⁇ p is measured, and the airflows of rooms Rl and R2 are calculated based on the calculation model and the pressure measurement.
  • the measured pressure difference can also be written in the form
  • ⁇ pa k2 3 , ⁇ -l q v ,tot, ⁇ (G)
  • Calculation step II The room airflows q v ⁇ ,m and qv2,m are measured, and these are compared with the airflows q v ⁇ , ⁇ and q V 2, ⁇ measured in accordance with the distribution network's calculation model.
  • Calculation step III The resistance values of room ducts are co ⁇ ected and provisional results ki,, and k2, ⁇ are calculated for branch resistances in the first step by regarding the branch duct resistance as known (value of the previous calculation round). Since the branch duct resistance is constant, the correction may be done in the room duct by the ratio method.
  • Calculation step IV The resistance value ki2, ⁇ of the branch duct component is corrected by the loop equation by regarding the room duct resistances as known (the previous equation).
  • Calculation step N The calculation continues from calculation step I, until the result of airflow measurements is sufficiently close to the result calculated by the distribution network model.
  • the room duct resistance is 1.2 times higher than the design value (ki, k2 and k 3 ).
  • the branch duct resistance is 1.3 times higher than the design value (ki2, k 23 and k 34 ).
  • Calculation also takes place at different opening positions of the damper, beginning from the fully open value. Calibration may continue at one or more smaller control positions (not fully open).
  • the room duct treatment is also different from the previous calculation example.
  • the room duct resistance is now treated in two separate parts: 1. Total flow resistance of the T branch, room branch duct and air terminal device 2. Flow resistance of the damper in a certain control position.

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Abstract

The invention concerns a method and equipment for determination of resistance values (k1, k2...) of an air-conditioning system's distribution networks (N1; U1, U2...; O1, O2...) in an air-conditioning system. In the method, the difference is calculated between the airflow measured in the room duct (O1, O2...) by an indicator (e1, e2...) or such and the airflow given by a distribution network model (150) into the concerned room duct (O1, O¿2...), and if the said difference is outside a certain predetermined tolerance range, the calculation to determine resistances, that is, the calibration calculation performed by a calculation unit (100) is used to change the distribution network resistances (k1, k¿2...) of the distribution network model (150), and the said calculation is performed again. When the difference between the measured flow rate and the calculated flow rate is within the tolerance range, the calculation is finished, whereby the resistances (k1, k2...) determined last represent the final distribution newtork resistances.

Description

Method and equipment for automatic determination of flow resistances in the distribution network of an air-conditioning system
The invention concerns a method and equipment for automatic determination of flow resistances in the distribution network of an air-conditioning system.
A model-based system has been developed for management and control of airflows, in which system known flow models of the distribution system and its components are used for controlling the desired airflows. In the control of a model-based air-conditioning system, the position of control elements controlling the volume airflows is determined centrally and simultaneously by information derived from the control unit of a controlling element located at the top hierarchy level. With the aid of theoretical resistance models the model parameters are first given initial values, which are corrected when required with the aid of checking measurements made in the field. Calibration of this model always calls for a manual checking measurement.
In traditional air-conditioning systems, the airflows are nowadays measured manually from each duct branch at the stage where the airflows are received and checked. The used method is quite laborious and expensive to implement. In addition, in field measurement conditions the measuring uncertainty is quite great, when the available pressure difference for measuring is small.
The present application proposes an improvement on the above-mentioned manual determination, that is, calibration, of flow resistances in a distribution network. In the system according to the invention, a certain chosen set of room and branch ducts is run up to a sufficient pressure level, whereby the uncertainty in measurement is small. In comparison with the present-day manual and in some cases quite inaccurate method, the developed method checks the airflows automatically. When calibrating in state-of-the-art systems, for example, in a system according to the applicant's earlier FI Patent Application 890170, this is already done entirely manually at the time when the system is delivered. This has meant that each room airflow into the room or out of the room has been measured separately, and the control units and their setting values have been changed separately for each room. Each room has been controlled separately, whereby several controls must be performed in each room so that the implemented airflows into all rooms are as close as possible to the desired values. The present application aims at disposing with the said manual calibration and to achieve a solution, wherein the correct resistance coefficients for each distribution network/control equipment are determined in one go, and thus the correct and desired airflows into the rooms/out of the room spaces are also obtained as the final results after the determination.
The invention concerns a method and equipment for automatic setting of the desired airflows in a model-based air-conditioning system. The air-conditioning system includes one or more air-conditioning units P to achieve the desired airflows and one or more distribution networks to conduct the airflows into the desired room spaces Rl, R2, ... or such and/or out of the room spaces Rl, R2, ... or such. For airflow management this application uses a model-based system as presented, the model parameters of which can be calibrated automatically with the aid of airflow measurement in the room duct and measurement of the static pressure in the distribution network and also with the aid of a calculated distribution network model. Using the calibration method it is possible automatically to check the correctness of airflows, for example, at the system's reception stage, without any manual measuring work.
The method and equipment for automatic determination of flow resistances in the distribution network of an air-conditioning system are characterised by the features presented in the claims.
In the following, the invention will be described with reference to some advanta- geous embodiments of the invention shown in the figures of the appended drawings, but the intention is not to restrict the invention to these only.
Figure 1 is a schematic view of an air-conditioning system according to the invention. The system shown in the figure includes supply air ducts and exhaust air ducts. The system includes zones, whereby the calculation of each zone is performed separately and the other parts of the system are closed during the calculation or they are set at minimum flow.
Figure 2 is a block diagram view of the method according to the invention for automatic determination of flow resistances in the distribution network of an air- conditioning system.
The air-conditioning system according to the invention shown in Figure 1 includes room and/or zone control units, airflow control equipment, such as dampers, for the airflow of different room ducts, an airflow measuring unit for the different room ducts, a branch duct pressure measuring unit, control equipment for the airflow of the whole air-conditioning unit, such as a blowing fan and its management/control equipment, data transmission buses t connecting the different pieces of equipment and a central processing unit (such as a PC) 200, wherein a calculating unit 100 and a distribution network model 150 are stored. Thus, the system may include zone- and/or room-specific equipment needed for airflow management and/or zone- and/or room-specific equipment needed for exhaust airflow management.
In the system according to the invention, the calibration calculation unit 100 used in calibration and the distribution network calculation model 150 are programmed and stored in a separate central processing unit 200, which includes memory and programming capacity. The calculations performed by the calculation unit 100, that is, the calibrated flow resistances, are updated to the distribution network's calculation model 150. The calculation model 150 corresponds with e.g. the state of the art, for example, with the system according to the earlier FI Patent Application 890170. In the solution according to the FI application, the calculation model of the distribution network controls the dampers in such a way that when the airflow into a room is changed, new setting values are given simultaneously to all dampers in the system, so that the desired room flow is implemented and the other room flows remain the same as before.
Default values for the duct resistances, distribution network components, such as the resistances of dampers and air terminal devices, or exacter initial values calculated on the basis of the plan and equipment data may be used as initial values for the calibration. In the method, the system automatically calibrates or determines by calculation the resistances to correspond with the real structure of the system.
In the automatic calibration system there are room duct-specific Oi, O2... airflow measuring equipment ei, e2... and static pressure measuring equipment PE for the branch distribution network Ui, U2..., whereby the measurements made with measuring equipment PE are used in the calibration of the model.
Figure 1 shows a division of the air-conditioning system into parts for determination of resistances, that is, for the calibration.
The air-conditioning system according to the invention includes in each room duct a measurement indicator or such which observes the airflow rate. In addition, each zone to be calculated includes a pressure indicator, with which the pressure level in each zone can be controlled/measured during the calibration. In addition, the air-conditioning system according to the invention includes a distribution network model 150, wherein are programmed and stored the calculation formulas for the zones of each distribution network system and wherein are stored the resistance values for the distribution network, dampers or such in their opening positions, for the air terminal devices, such as the register, which resistance values are obtained through tabular books or various calculations. The distribution network model 150 includes programming capacity, and the resistance parameters for the concerned model can be stored in the memory of distribution network model 150 and can be programmed in calculation formulas. Each damper or other such device control- ling the airflow and the blowing device bringing about the airflow include a separate control unit controlling the settings of the damper/blowing fan, whereby the blowing fan can be controlled to produce a certain pressure in the distribution network and the dampers are fitted so that their opening can be set in accordance with the room requirements. Through data transmission buses the control units are connected with a central processing unit 200. The central processing unit 200 includes a central calculation unit 100 according to the invention performing the calibration and a distribution network model 150 of the system. The central processing unit 200 may be formed by e.g. a PC or other computer. In this application, the calculation unit 100 includes the presented calibration formulas and initial parameters for the formulas, which perform calculation of the resistances ki, k2... and which relate to the distribution network, the ducts proper, the dampers or corresponding air terminal devices.
Different distribution network zones or sectors Ai, Bi, Ci... both on the supply airflow side and on the exhaust airflow side from room Ri, R2... are drawn in
Figure 1. The blowing fan or air-conditioning unit is indicated by the symbol P! in the figure. There is a trunk duct Ni, which divides the airflow into the different zones Ai, Bi, Ci ... or in the equivalent way on the outcoming side of air from the different zones Ai, Bi, Ci ... From trunk duct Ni branch ducts Ui, U2... branch off and these branch off further into room ducts Oi, O2, O3... Each room duct Oi, O2,
O3... includes a control device controlling the airflow, such as a damper or such
Si, S2, S3..., and in connection with the concerned control device a measurement indicator or such ei, e2, e3... measuring the airflow. From the central processing unit 200 of the equipment there is a data transmission connection along data transmission buses t with the devices Si, S2... controlling the airflow, with their control motors or such, and correspondingly, with the device controlling the speed of rotation of blowing fan P or with the device or motor controlling the airflow of air-conditioning unit P. In the figure, the ducts on the supply side and exhaust side of rooms Ri, R2... are marked with the same indices. Thus, the method according to the invention may be implemented for the supply airflow into its sectors Ai, Bi, Ci ... or on the exhaust air side into sectors Ai, Bi, Ci... of the exhaust airflow. The pressure indicator, for example, in branch duct Ui, is marked as PE.
According to the invention, each room duct Oi, O2... near the control device controlling the airflow, such as a damper Si, S2... includes in the room duct Oi, O2... an indicator ei, e2... or such measuring the airflow rate [1/s]. In the system according to the invention, a pressure indicator PE measuring the distribution network pressure is preferably located in the branch duct Ui, U ... of each sector Ai, Bi... Blowing fan P is adapted to produce an airflow into each sector Ai,
Figure imgf000008_0001
Ci... A similar arrangement is on the exhaust side, whereby the blowing fan produces an exhaust airflow from each room space Ri, R2... The exhaust side correspondingly also includes room ducts Oi, O2..., which are joined to the branch ducts Ui, U2..., which are further joined to trunk duct Ni, wherein the exhaust fan P is installed. Each control device Si, S2..., such as a damper, includes associated with itself as a control unit a motor or such, to which a data transmission bus t leads from central processing unit 200 in order to control the concerned damper. Correspondingly, from indicators ei, e2... there is a data transmission bus t to the central processing unit to transmit measurement data to central processing unit 200. The central processing unit 200 associated with itself includes a calculation unit 100 performing calculation to determine the resistances ki, k ... and a distribution network calculation model 150 is installed/stored in central processing unit 200 and the distribution network as formulas and parameters, such as resistance coefficients. To determine the parameters of this distribution network model 150, such as the resistance coefficient of the distribution network resistances ki, k2..., the method and equipment according to the invention are used. In this application, the determination of the resistance ki, k2... to correspond with the reality is also called calibration. Room ducts Oi, O2... are discussed in the following. When discussing branch ducts in the following, those ducts Ui, U2... are meant, with which room ducts Oi, O2... are joined. The branch ducts Ui, Hi... are further joined to trunk duct Ni. Each sector Ai, Bi, Ci ... is defined in such a way that it includes a branch duct and the joining room ducts.
When discussing distribution network model 150, this means the calculation model relating to the concerned distribution network. Central processing unit 200 may be a PC or other computer.
Thus, the present application presents a method and equipment for performing automatic calibration in an air-conditioning system. For fresh supply air the air- conditioning system includes a blowing fan, a frunk duct and branch ducts, which branch off further into room ducts. The system may further for exhaust air from each room include room ducts joining the branch duct, which is joined further to the trunk duct. Each room duct includes an airflow control device to control the airflow rate.
The air-conditioning system may also include just a trunk duct, a branch duct and room ducts, through which fresh air is supplied, or the system may also include just the exhaust ducts, as described above. From the trunk duct supply airflows are branched off into several branch ducts and further from the branch ducts into the room ducts. In a special case the distribution network may lack the branch duct level, and the room ducts Oi, O2... branch off directly from the trunk duct Ni. Hereby the trunk duct Ni functions mainly in the same way as the branch duct Ui, U2... presented in this application. There may be a similar aπangement also for the air exhaust or only for this. According to the invention, the room ducts include a control device controlling the airflow, for example, a damper, to control the airflow rate into the room space/out of the room space. In addition, there is a blowing fan in the trunk duct, which is used to control the pressure level in the ducts and thus the airflow into the distribution network. Both the airflow control devices, such as dampers or such, and the blowing fan include control devices to control the airflow control device and to control the blowing fan.
In the applicant's known earlier air-conditioning system, all dampers are controlled simultaneously based on setting value information supplied from the distribution network model 150, whereby when the airflow is controlled in one room space, the airflow control devices of the other room spaces are affected at the same time, so that the airflows in the other room spaces will remain at their desired controlled values. Calibration of the above-mentioned air-conditioning system has been performed manually in connection with the delivery of the system, whereby it has been necessary to measure pressures and flows into each room space separately. This manual calibration has been a very time-consuming and thus expensive arrangement.
This application presents an automatic calibration system for an air-conditioning system. According to the invention, in each room duct a measuring device, e.g. a measurement indicator, is located to measure the airflow rate. In addition, in each branch duct a measurement indicator is located to measure the pressure. Starting of the automatic calibration takes place at each branch duct in such a way that the airflow connections with the remaining network are closed off and the blowing fan is operated to produce a certain pressure level. All dampers of the concerned calibration area are set in a certain position. The resistance coefficients of the dampers are known, but the distribution network resistances are determined in the system based on certain tabular books and types of flow resistance structures. In order to be able to correct the said values, the automatic calibration is carried out in accordance with the invention by using flow equations known as such and a loop method in the calculation. The calculation formulas are stored in distribution network model 150, and in the calculation unit 100 performing calibration, that is, determination by calculating the flow resistances. In the calculation, calibration takes place set-wise in such a way that the room ducts and branch ducts belonging to a certain calibration set are calibrated at a time. Calculation begins e.g. from the calibration set located nearest to the pressure indicator PE, and the calculation proceeds from the first calibration set first in the direction of airflow towards the branch duct end and finally from the first calibration set in a counter-current direction towards the blowing fan.
The blowing fan is run to produce a certain predetermined pressure value, which is measured by the pressure indicator PE or such from the branch duct. The pressure indicator is set at a certain place in the branch duct. This place is ύrelevant as such. Calculation proceeds in such a way that coπected duct resistances are obtained as the result of the calculation.
The calibration arrangement in question may also be performed similarly with the exhaust ducts.
In the second stage, the airflows of the branches are measured and they are compared with the airflows given by the calculation formulas, that is, by the model. When a sufficient deviation occurs between airflows, a new value is set for the room duct's resistance. The said new value can be given by weighting the resistance calculated on the basis of measurements and the earlier value with a weighting coefficient.
In the third stage, after coπecting the resistance, the new room duct-specific airflows are measured. With the aid of the measurement results and the loop equations between room branches (starting point: the pressure loss of a closed circuit is 0, because the rooms are at the same pressure as default value) new resistances based on measurement are calculated for the branch duct components. A new value is given to the branch duct's resistance by weighting the value calculated on the basis of measurements and the earlier value with the set weighting coefficient. The new resistance values of the branch duct components are set and the iteration calculation is repeated, until the room duct-specific airflows are sufficiently accurate. Besides duct resistances, resistances for the dampers of room ducts in their different control positions may be calculated with the above-mentioned method by utilising the distribution network resistances already calculated.
Figure 2 is a block diagram view of a method for determination of resistances.
In the calibration, which in this application means an exact determination of resistances, the distribution network is thus divided into parts, through which a suitable airflow passes to achieve reliable measurements. In connection with the calibration all dampers to be calibrated are set in control positions, where a sufficient flow resistance arises in them, and the other brancl-i/trunk dampers are closed. In the calculation, calibration takes place set-wise in such a way that the room ducts and branch ducts belonging to a certain calibration set are always calibrated at a time.
The calculation is started e.g. from the calibration set located nearest to the pressure indicator PE, and the calculation proceeds manually from the first calibration set, first in the flow direction towards the branch duct end and finally from the first calibration set manually in a counter-current direction towards the blowing fan.
In the first stage of calibration, the chosen dampers to be calibrated are given setting values, on the basis of which a setting value is calculated for the trunk duct's static pressure using the system model. The said static pressure is regulated by using the blowing fan.
In the method according to the invention, the distribution network is divided into zones Ai, Bi, Ci ..., that is, into sectors, whereby each sector Ai, Bi, Ci ... includes a branch duct Ui, U2... branched off from the trunk duct Ni and room ducts Oi, O2... branched off from the branch duct and opening into the rooms. The room ducts Oi, O2... include flow-controlling control devices Si, S2..., such as dampers, and measuring devices ei, e2... indicating the airflow rate, such as measurement indicators. Calculation as regards distribution network resistances as well as damper resistances takes place zone-wise Ai, Bi, Ci..., so that each zone Ai, Bi, Ci ... is calculated separately while the other zones of the air-conditioning system are closed off or are set at a minimum flow rate during the calculation. In the distribution network calculation, an iteration calculation method is used to determine the correct distribution network resistances, and the calculation/iteration is continued until the air rate indicated by the distribution network's calculation model is equal with sufficient exactitude to the measured air rate at a certain static pressure in the distribution network and at certain openings of the devices controlling the flow rate. The calculation proceeds in such a way that the calculated distribution network resistances at the end of the iteration round function as a basis for the calculation in the following stage, when damper resistances are determined. The calculation for dampers is quite the same. Hereby the dampers are set at a certain opening position. As regards resistances the dampers may be calculated in different opening positions, whereby a certain resistance curve is obtained for the dampers or such depending on the damper's opening position.
Calculation example - automatic calibration of the distribution network model
This example presents calculation of the room ducts of two rooms (Rl and R2) and of the branch duct between them and calibration of the model. The damper is fully open.
Figure imgf000014_0001
R2 R l
Figure 1: Diagram of distribution network
The equations are in the form:
Δp = k23 (qv2 + qvι + qvo) + kι2 (qvι + qvo) + k] qvι (A), pressure loss from pressure indicator PE to room Rl
9 7
Δp : k23 (qV2 + qvi + qv0) + k2 qV2 (B), pressure loss from pressure indicator PE to room R2
k2 qv2 + kι2 (qvι + qv0) + ki qvl = 0 (C), pressure loss between the rooms, here Δp = 0
To simplify the presentation, qv0 is 0 hereinafter, and it will not be present in the equations.
Symbols used
Δp is the static pressure difference, magnitude to be measured [Pa] qv0 is the airflow in the branch duct after room Rl (known) [1/s] qvι is the airflow in room Rl [1/s] qv2 is the airflow in room R2 [1/s] k23 is the resistance in the branch duct between the pressure indicator and room duct R2 kι2 is the resistance in the branch duct between room ducts R2 and Rl ki is the resistance of room duct Rl : of damper (open), duct, air terminal device and T-branch k2 is the resistance of room duct R2: of damper (open), duct, air terminal device and T-branch ωh is the weighting coefficient (0...1), e.g. 0.3 ωp is the weighting coefficient (0...1), e.g. 0.3 ε is the maximum permissible eπor in the room duct's airflow
Subindices: i-1 is the calculated value or initial value of the previous iteration round i is the calculated provisional result of this iteration round i+1 is the final result of this iteration round, which is the initial value for the following round m is the measured result
Calculation step I: Calculation step I presents an alternative way of calculating the airflow rate. In the airflow calculation, e.g. the distribution network model 150 stored in central processing unit 200 may be used, similar to the one presented e.g. in the applicant's FI Application 890170.
The pressure difference Δp is measured, and the airflows of rooms Rl and R2 are calculated based on the calculation model and the pressure measurement.
Δp = k23,ι-ι (qv2,i + qvi,i) + k2ji-ι qv2)ι (D)
Δp = k23)ι-ι (qV2,ι + qvi, + (ki2,i-ι + kι,i-ι) qvι,i (E) In the equations above there are two unknowns, so that qvι;] and qV2,ι can be solved. The solution is by either the iterative method or generally by the known method of calculating resistances connected in parallel and in series (Figure 2).
Figure imgf000016_0001
Solution of airflows by the resistance method
The measured pressure difference can also be written in the form
Δp = Δpa + Δpb = k,-ι qV)tot,ι (F)
Δpa = k23,ι-l qv,tot,ι (G) Δpb = (ki2,ι-ι + kι,,-ι) qvι,, = k2>1-ι qv2>, (H)
from which the airflows qvι,ι and qv2,ι can be solved in accordance with the model.
Calculation step II: The room airflows qvι,m and qv2,m are measured, and these are compared with the airflows qvι,ι and qV2,ι measured in accordance with the distribution network's calculation model.
Figure imgf000017_0001
I qV2,ι - qv2,m I < ε (J)
If the difference is below the acceptance limit, the calculation is finished. Otherwise the calculation proceeds to calculation step IH
Calculation step III: The resistance values of room ducts are coπected and provisional results ki,, and k2,ι are calculated for branch resistances in the first step by regarding the branch duct resistance as known (value of the previous calculation round). Since the branch duct resistance is constant, the correction may be done in the room duct by the ratio method.
2 2 2
Δp = kι,ι-ι qvι,ι = kι,ι qvι,m => kι,ι = kι,ι-ι (qvι,, / qvι,m) (K)
2 2 2
Δp = k2,,-ι qV2,ι = k2,ι qV2,m => k2>1 = k2,ι-ι (qV2,ι / qv2,m) (L)
However, any change in the room duct resistance is not taken into account with full weight, but the result of the following iteration round is weighted between the value calculated now and the value of the previous iteration round.
kι,ι+ι = (1 - ωh) kι,,-i + ωh kι,,-ι (qvι,ι / qvι,m) (M) k2;1+ι = (1 - coh) k2,,-ι + ωh k2,,-ι (qV2,ι / qV2,m)2 (N)
Calculation step IV: The resistance value ki2,ι of the branch duct component is corrected by the loop equation by regarding the room duct resistances as known (the previous equation).
k2,ι+l qV2,m + (ki2,ι + kι,,+ι) qvi,m = 0 .(O) However, any change in the branch duct resistance is not taken into account with full weight, but the result of the following iteration round is now weighted between the value calculated now and the value of the previous iteration round.
ki2,i+ι = (1 - ω P) ki2.i-ι + ω ki2,i (P)
Calculation step N: The calculation continues from calculation step I, until the result of airflow measurements is sufficiently close to the result calculated by the distribution network model.
Calculation example - automatic calibration of the distribution network calculation model
Design values: ki = k2 = k3 = Lt = 0.006, which coπesponds with the resistance Δp = 60 Pa of each room duct when qv = 100 1/s.
The pressure loss of branch duct components is 15 Pa, that is, ki2 = 0.0015, k23 = 0.000375 and k3 = 0.000167.
In reality, the room duct resistance is 1.2 times higher than the design value (ki, k2 and k3). In reality, the branch duct resistance is 1.3 times higher than the design value (ki2, k23 and k34).
In this calculation example, the resistances are presented by three marking numbers, while greater precision is used in the calculation of results. TABLE 1 PE = 100 Pa
Figure imgf000019_0001
Measured 130 1/s 118 l/s 106 l/s 94 l/s 1=0 Calculated 141 l/s 1-29 l/s 117 l/s 104 l/s
1=1 k4 = 0.00634 k3 = 0.00636 k2 = 0.00639 1^ = 0.00643 1=1 k34 = 0.000171 k23 = 0.000406 k12 = 0.00154 1=1 Calculated 137 l/s 125 l/s 113 l/s 101 l/s
l=2 k4 = 0.00656 k3 = 0.00661 k2 = 0.00666 k, = 0.00674 l=2 k34 = 0.000174 k23 = 0.000422 k12 = 0.00156 l=2 Calculated 135 l/s 123 l/s 111 l/s 99 l/s
l=3 k4 = 0.00670 k3 = 0.00679 k2 = 0.00685 k, = 0.00697 l=3 k34 = 0.000174 k23 = 0.000433 k12 = 0.00157 l=3 Calculated 132 l/s 121 l/s 109 l/s 98 l/s
l=4 k4 = 0.00680 k3 = 0.00691 k2 = 0.00698 kι = 0.00714 l=4 ks4 = 0.000174 k23 = 0.000442 k12 = 0.001575 l=4 Calculated 131 l/s 120 l/s 108 l/s 97 l/s
I =5 k4 = 0.00686 k3 = 0.00700 k2 = 0.00701 ki = 0.00728 l=5 k34 = 0.000174 k23 = 0.000449 k12 = 0.00157 l=5 Calculated 131 l/s 119 l/s 107 l/s 96 l/s
Measured, 130 l/s 118 l/s 106 l/s 94 l/s in front Calculation example - calibration of damper
Calculation is by the coπesponding principle as in the calculation examples presented above, except that calculation step IN is left out entirely from the iteration calculation.
Calculation also takes place at different opening positions of the damper, beginning from the fully open value. Calibration may continue at one or more smaller control positions (not fully open).
The room duct treatment is also different from the previous calculation example. The room duct resistance is now treated in two separate parts: 1. Total flow resistance of the T branch, room branch duct and air terminal device 2. Flow resistance of the damper in a certain control position.
That is, in the equation presented above
Δp = k23 (qv2 + qvι) + (kι2 + ki) qvι (A), pressure loss from pressure indicator PE to room Rl Δp = k23 (qv2 + qvι)2 + k2 qV2 (B), pressure loss from pressure indicator PE to room R2
the total room duct resistance is placed in two parts
ki = ki,h + ki,a (Q) k2 = k2;h + k2)a (R) wherein ki is the total room duct (Rl) resistance, when the damper is in certain control positions k2 is the total room duct (R2) resistance, when the damper is in certain control positions kι,h is the totalled resistance of the T branch, duct, open damper and air terminal device k2,h is the totalled resistance of the T branch, duct, open damper and air terminal device k1>a is the resistance of the damper in certain positions, kι,a = 0 when the damper is open k2,a is the resistance of the damper in certain positions, k2,a = 0 when the damper is open.
One of these openings is presented in the following calculation example.
Calculation example - damper calibration
The damper is guided to a position, which at the damper's flow rate of 100 1/s coπesponds with a pressure loss of 30 Pa => ki = 0.0030.
Due to a damper position eπor or some other reason, there is a 10 % error in the damper's resistance value at this opening, and due to the error the share of each damper in the total resistance is k = 0.0033 in reality.
In this calculation example, the resistances are presented by three significant numbers, while greater precision is used in the calculation of results. TABLE 2
PE = 150 Pa
Figure imgf000022_0001
Measured 129 l/s 120 l/s 110 l/s 101 l/s l=0 Calculated 131 l/s 122 l/s 113 l/s 104 l/s l=0 k, = 0.00986 k3 = 0.00100 k2 = 0.0101 k! = 0.0103
1=1 Calculated 130 l/s 122 l/s 112 l/s 104 l/s
1=1 k4 = 0.00998 k3 = 0.0101 K2 = 0.0102 k, = 0.0105 l=2 Calculated 130 l/s 121 l/s 112 l/s 103 l/s l=2 k4 = 0.0101 k3 = 0.0103 K2 = 0.0103 k! = 0.0106 l=3 Calculated 129 l/s 121 l/s 112 l/s 103 l/s l=3 k4 = 0.0101 k3 = 0.0103 K2 = 0.0104 ki = 0.0107 i=4 Calculated 129 l/s 120 l/s 111 l/s 102 l/s l=4 k4 = 0.0102 k3 = 0.0104 K2 = 0.0104 ^ = 0.0108
Measured, 129 l/s 120 l/s 110 l/s 101 l/s in front

Claims

Claims
1. Method for determination of resistance values in distribution networks (Ni; Ui, U2...; Oi, O2...) of an air-conditioning system in an air-conditioning sys- tern, which includes at least one blowing fan (P) to bring about an airflow into the trunk duct (Ni) and further into branch ducts (Ui, U2...) branched off from it, which branch ducts branch off further into room ducts (Oi, O2...), whereby the room ducts (Oi, O2...) include control equipment (Si, S2...), such as dampers, controlling the airflow and its flow rate, whereby the control equip- ment (Si, S2...) includes in association therewith control units and, correspondingly, the blowing fan (P) includes associated therewith a control unit, which through data transmission buses (t) are in connection with a central processing unit (200) to control the blowing fan (P) and to control the setting values of the airflow control equipment (Si, S2...), such as dampers, and in that the method uses such a control system, which includes a calculation central unit (100) to calibrate the flow parameters and a distribution network model (150) to store a calculated distribution network model for the air- conditioning system and the related mathematical equations and parameters, such as distribution network resistances, whereby the distribution network model (150) can be used to calculate room-specific airflows at different pressures and at different control equipment positions, characterised in that the method uses a measuring device (ei, e2...) or a measurement indicator to measure each room-specific airflow in the room duct (Oi, O2...), and that the method uses a pressure indicator (PE) or such, which can be used to measure the distribution network pressure in each distribution network zone (Ai, Bi,
Ci...), and that in the method the difference is calculated between the airflow measured by the indicator (ei, e2) or such in the room duct (Oi, O2...) and the airflow given by the distribution network model (150) into the concerned room duct (Oi, O2...), and if the said difference is outside a certain predetermined tolerance range, the determination or calibration calculation of resistances performed by the calculation unit (100) is used to change the distribution network resistances (ki, k2...) of the distribution network model (150), and the said calculation is performed once again, and when the difference between the measured flow rate and the calculated flow rate is within the tolerance range, the calculation is finished, whereby the resistances (ki, k2...) determined last represent the final distribution network resistances.
2. Method according to claim 1, characterised in that in the method the distribution network resistances (ki, k2...) of the air-conditioning system's air- conditioning ducts (Ni; Ui, U2...; Oi, O2...), such as the trunk duct (Ni), branch duct and room ducts (Oi, O2...), are determined by a) opening the dampers (Si, S2...) belonging to a certain calibration set, b) by setting the distribution network pressure in the concerned calculation sector (Ai, Bi, Ci ...) at the calibration value of the distribution network, which calibration value is given in advance, which pressure is measured by a pressure indicator (PE) in a branch duct (Ui, U2...) of the sector (Ai, Bi, Ci...) and based on which pressure the airflows of room branches (Oi, O2...) are calculated in accordance with the distribution network model, and the concerned airflow values according to the model are compared with the values measured by indicators (ei, e2) from the room branches (Oi, O2...), and if the difference between the said measured airflow rate values of the room branches (Oi,
O2...) and the airflow rates of the room branch (Oi, O2...) given by the distribution network model (150) is outside a certain tolerance value, the resistance values (ki, k ) of the room ducts (Oi, O2...) and branch ducts (Ui, U2...) of the zone (Ai, Bi, G...) are changed with the aid of a calculation unit (100) per- forming calibration calculation, and then a new calculation is performed of the airflow rates of room branches (Oi, O2...) until the difference between the airflow rates of room ducts given by the distribution network model (150) and the measured airflow rates is within a certain tolerance range, whereby the said last calculation will determine the resistance values (ki, k2) of the distribution network, which will then function as resistance values of the distribution network model (150), when controlling airflows into room spaces/out of room spaces in a normal operation of the distribution network system.
3. Method according to claim 1, characterised in that in the method when determining distribution network resistances (ki, k2), the dampers (Si, S2...) or such in the room ducts (Oi, O2...) are first set in an open position, whereby a free airflow is allowed through the dampers (Si, S2.. ■)•
4. Method according to claim 3, characterised in that in the method after the determination of distribution network resistances (ki, k2) the dampers (Si, S2...) or such are set in a new position in a certain zone (Ai, Bi, Ci ...) of the air-conditioning system and the distribution network pressure is set at the calibration value of dampers and the concerned pressure is measured by a pressure indicator (PE), and then the air rates of room ducts (Oi, O2...) are measured and the airflow rates of room ducts (Oi, O2...) given by the distri- bution network model are compared with the airflow rate values [1/s] of room ducts (Oi, O2...) measured by indicators (ei, e2...) or such located in the room ducts (Oi, O2...), and if the difference between the said airflow rates in each room duct (Oi, O2...) is outside a certain tolerance range, the resistance values (kls k2...) of the flow control equipment (Si, S2...), such as dampers, are cor- rected with the aid of the calculation unit (100), and then a new calculation of the airflows of room ducts (Oi, O2...) is performed until the difference between the airflow rate value measured by the indicator (ei, e2...) and the calculated airflow rate value given by the distribution network model (150) in each room duct (Oi, O2...) is within a certain tolerance range, whereby the said last calculation will determine the resistance value (ki, k2...) for each damper (Si, S2...) or such at its concerned setting, that is, opening position.
5. Method according to any preceding claim, characterised in that in the method the entire system is gone through zone- wise (Ai, Bi, Ci...) by applying cali- bration to a certain zone (Ai, Bi or Ci ...) and by hereby closing the other zones for the time of calibration or by setting them at a minimum flow.
6. Method according to any preceding claim, characterised in that in each room duct (Oi, O2...) there is equipment measuring the airflow rate (1 s), such as a measurement indicator (ei, e2...), and that each zone (Ai, Bi, Ci...) includes branch ducts (Ui, U2...) and room ducts (Oi, O2...) and preferably an indicator
(PE) or such measuring the static air pressure in the branch duct (Ui, U2...).
7. Method according to any preceding claim, characterised in that the method uses a calculation unit (100) to calibrate and coπect the flow parameters and a distribution network model (150), which includes memory and programmabil- ity, whereby in the memory of the said distribution network model (150) are stored in the air-conditioning system's distribution network model the calculation formulas relating to the different duct zones (A, B, C ...) and the parameters relating to these, such as the resistance coefficients (ki, k2...) of the distribution networks (Ui, U2...; Oi, O2...) and dampers (Si, S2...), and that the calculation unit (100) performing determination calculation of resistances, that is, calibration, and the distribution network calculation model (150) are stored as formulas in the central processing unit (200).
8. Equipment for automatic determination of flow resistances in the distribution network of an air-conditioning system, which air-conditioning system includes at least one trunk duct (Ni) and therein a device bringing about airflow, such as a blowing fan (P), and that the air-conditioning system includes at least one branch duct (TJi) branched off from the trunk duct (Ni) and room ducts (Oi, O2, O3...) branched off from it into rooms (Ri, R2 ...), whereby each room duct (Oi, O2...) includes a damper (Si, S2...) or such controlling the supply airflow into the room or the exhaust airflow from the room, which damper includes associated with it a control unit, a damper (Si, S2...) or such to give a setting value and to position the damper, and that the room duct (Oi, O2...) includes a measurement indicator (e1; e2...) measuring the airflow rate, which can be used to measure the airflow rate (1/s) of the room duct, and that the air- conditioning system in the branch duct (Ui, U2...) includes a measurement indicator (PE) measuring the static pressure in the distribution network, characterised in that the dampers (S S2...) or such located in the room ducts (Oi, O2...), their control units are connected through data transmission buses (t) with the central processing unit (200) for the air-conditioning system's control and, correspondingly, the control unit controlling the blowing fan (P) or such is connected with the system's central processing unit (200), which includes a calculation unit (100) performing calculation to determine the resistances, that is, calibration calculation, and a distribution network model (150), which includes calculation formulas, parameters, such as the resistances (ki, k2...) of the distribution network and the dampers, whereby in the determination of the final values of resistances (ki, k2...) the resistances (ki, k2...) in each system sector (Ai, Bi, Ci ...) are changed with the aid of calculation performed by the calculation unit (100), and in each calculation the difference is calculated between the airflow rate of the room duct (Oi, O2...) given by the distribution network model (150) and the airflow rate indicated by the indicator (ei, e2...) as measured from the concerned room duct (Oi, O2...), and when the difference is within a certain tolerance range, the calculation is finished, whereby the resistances (ki, k2...) calculated last are placed in the distribution network model (150) as the final resistances.
PCT/FI2002/000109 2001-02-16 2002-02-13 Method and equipment for automatic determination of flow resistance in the distribution network of an air-conditioning system WO2002066903A1 (en)

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FI20010306A FI114567B (en) 2001-02-16 2001-02-16 Method and plant for automatically determining the flow resistances in the ducts of an air conditioning system

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PCT/FI2002/000109 WO2002066903A1 (en) 2001-02-16 2002-02-13 Method and equipment for automatic determination of flow resistance in the distribution network of an air-conditioning system

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2930017A1 (en) * 2008-04-15 2009-10-16 Atlantic Climatisation & Venti Ventilation group regulating method for ventilating room, involves examining air flow derivative cyclically to bring modification, at air flow set point value, in order to reduce derivative, in case of detection of derivative
EP2937673A3 (en) * 2014-04-24 2015-11-04 Ideal Clima S.r.l. Meter for measuring the flow rate of aeriform substances and method for measuring the flow rate of aeriform substances with said meter
WO2019040067A1 (en) * 2017-08-24 2019-02-28 Siemens Industry, Inc. System and method for controlling building fluid distribution
EP3712527A1 (en) * 2019-03-18 2020-09-23 Trox GmbH Method for balancing the volumetric flows of multiple air passages
US11125453B2 (en) 2016-03-10 2021-09-21 Carrier Corporation Calibration of an actuator
WO2023192007A1 (en) * 2022-03-31 2023-10-05 Siemens Industry, Inc. Controller and method for managing a flow unit

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US5071065A (en) * 1989-01-13 1991-12-10 Halton Oy Procedure for controlling and maintaining air currents or equivalent in an air-conditioning installation, and an air-conditioning system according to said procedure
US5139197A (en) * 1989-12-07 1992-08-18 Mitsubishi Denki Kabushiki Kaisha Air conditioning system
EP0721088A1 (en) * 1995-01-06 1996-07-10 LANDIS &amp; GYR POWERS, INC. Global control of hvac distribution system
EP0819895A2 (en) * 1996-07-17 1998-01-21 LANDIS &amp; STAEFA, INC. Automated branch flow calibration in a HVAC distribution system

Patent Citations (4)

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Publication number Priority date Publication date Assignee Title
US5071065A (en) * 1989-01-13 1991-12-10 Halton Oy Procedure for controlling and maintaining air currents or equivalent in an air-conditioning installation, and an air-conditioning system according to said procedure
US5139197A (en) * 1989-12-07 1992-08-18 Mitsubishi Denki Kabushiki Kaisha Air conditioning system
EP0721088A1 (en) * 1995-01-06 1996-07-10 LANDIS &amp; GYR POWERS, INC. Global control of hvac distribution system
EP0819895A2 (en) * 1996-07-17 1998-01-21 LANDIS &amp; STAEFA, INC. Automated branch flow calibration in a HVAC distribution system

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2930017A1 (en) * 2008-04-15 2009-10-16 Atlantic Climatisation & Venti Ventilation group regulating method for ventilating room, involves examining air flow derivative cyclically to bring modification, at air flow set point value, in order to reduce derivative, in case of detection of derivative
EP2937673A3 (en) * 2014-04-24 2015-11-04 Ideal Clima S.r.l. Meter for measuring the flow rate of aeriform substances and method for measuring the flow rate of aeriform substances with said meter
US11125453B2 (en) 2016-03-10 2021-09-21 Carrier Corporation Calibration of an actuator
WO2019040067A1 (en) * 2017-08-24 2019-02-28 Siemens Industry, Inc. System and method for controlling building fluid distribution
US11268714B2 (en) 2017-08-24 2022-03-08 Siemens Industry, Inc. System and method for controlling building fluid distribution
EP3712527A1 (en) * 2019-03-18 2020-09-23 Trox GmbH Method for balancing the volumetric flows of multiple air passages
WO2023192007A1 (en) * 2022-03-31 2023-10-05 Siemens Industry, Inc. Controller and method for managing a flow unit
US12072115B2 (en) 2022-03-31 2024-08-27 Siemens Industry, Inc. Controller and method for managing a flow unit

Also Published As

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FI20010306A (en) 2002-08-17
WO2002066903A8 (en) 2003-11-20
FI114567B (en) 2004-11-15
FI20010306A0 (en) 2001-02-16

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