EP1754005A1

EP1754005A1 - Method for balancing emitters in a heating system

Info

Publication number: EP1754005A1
Application number: EP05773263A
Authority: EP
Inventors: Patrick Delpech
Original assignee: Gefen (Lycee Maximilien Perret)
Current assignee: Gefen (Lycee Maximilien Perret); MAPSEC
Priority date: 2004-05-26
Filing date: 2005-05-25
Publication date: 2007-02-21
Anticipated expiration: 2025-05-25
Also published as: ES2529450T3; FR2870927A1; PL1754005T3; DK1754005T3; FR2870927B1; EP1754005B1; WO2005119129A1; PT1754005E

Abstract

The invention relates to a method for balancing a heating system comprising at least one series (R1, R2, Rn) consisting of at least one emitter. The method is characterized in that it comprises steps consisting in measuring the temperatures (TA, Tb) of the feed channel (1) upstream from said series, in determining a reference differential (dtref); in measuring the temperature (tsn) at the output of each emitter; in determining, for each series, the difference between the temperature (TA) upstream from the first series and the output temperature (tsn) of each series; in establishing a measurement corrector coefficient (A) for each series; and in establishing a relative flow coefficient (Q %n) for each series (R1, R2, Rn).

Description

METHOD FOR BALANCING THE TRANSMITTERS OF A HEATING FACILITY

The present invention relates to a method of balancing a heating / cooling installation of two-tube water circulation type premises. It is known that the balancing of a central heating installation with hot water circulation is to ensure a distribution of the flow of water circulation pumps that is in correspondence with the power of the irrigated radiators. In this type of installation it is known that the radiators are arranged in a bypass between a hot water supply line and a return line. In general, each radiator is provided with a balancing valve whose position makes it possible to control the flow of hot water through it and, consequently, the quantity of heat delivered by it. This type of faucet is called a first-level balancing valve because it allows the flow rate to be adjusted as close as possible to one or more radiators. It is known that when the installation is important, there are provided second level valves that allow the adjustment of the flow of a set of radiators balanced with each other by the first level valves. It is known that when the installation is very important, there are provided third-level valves that allow the adjustment of the flow of several sets of radiators balanced with each other by the second-level valves. One of the difficulties encountered when the balancing of this type of installation is poorly achieved stems from a poor distribution of the flow rates between the various radiators or sets of radiators which generates differences in heating, which are widening when the outside temperature decreases. Such a situation is extremely frequent, especially in old installations, and results in discomfort for the user and significant overconsumption of up to 10 to 20%. The search for a good balance of an installation is made difficult because, when one performs a correction of flow on one of the radiators of an installation, one modifies at the same time the flow of the other radiators of this same installation. To avoid this drawback, it has been proposed in the prior art to precompute the adjustment position of all the faucets of the installation. Such an operation, delicate because of its complexity, also requires the designer to have all the exact plans of the installation which, in the case of old installations, most often forced the user to redo a complete record of the distribution. It has also been proposed to achieve such balancing by measuring, on special valves, the flow of hot water through each valve and correcting the flow thereof appropriately. This flow measurement is usually performed by measuring the pressure drop that exists on the control valve. Then applying various methods converges to a balance, and more or less easily depending on the installation. The major drawbacks of this balancing technique are that, on the one hand, it requires an installation with special valves to perform such a measurement and that, on the other hand, it is necessary to know the flow rates to be adjusted which, in the case of installations old, usually requires a complete record of the distribution. It has also been proposed in Application FR-A-2 795 491 and in the case of the adjustment of first-level valves associated with radiators, that is to say transmitters whose hydraulic resistance is negligible compared to that of valves, to measure the temperatures of the supply and return lines at the radiator located furthest upstream of the series, and to determine the difference in temperature between these two values, hereinafter referred to as the "reference difference", to determine for each radiator in the series, the difference between the inlet temperature of the radiator the most upstream and the exit temperature of the radiator considered, hereinafter referred to as "specific deviation", to establish, for each radiator of the series a correction coefficient equal to the difference between the value of the reference deviation and a value constituted by the difference existing between the aforesaid value of the reference deviation and the aforesaid value of the specific deviation multiplied by an adjustment coefficient, established empirically at a value close to 2. According to this method, for each radiator, a relative flow coefficient equal to the ratio of the reference difference on the corrective coefficient of measurement. This corrects the feed rate of a given radiator by multiplying its flow by the inverse of the relative flow coefficient. In order to carry out this operation, curves are available which express the relative flow variation q% _Rn of a valve of a given brand and type as a function of the number of revolutions N of its regulator and this for a constant pressure difference. . These relative flow curves q% _Rn of a valve of a given brand and type as a function of the number of revolutions N of its regulator and this for a constant pressure difference are made available by the manufacturer or, if not, are measured on a hydraulic bench. Thus determined this relative flow rate variation q% _Rn is that specific to a given brand and type valve installed alone without other hydraulic resistance in series. It will be understood that, when the valve is in series with another hydraulic resistor, this relative flow rate variation q% _Rn specific to the valve is no longer usable and this especially as this hydraulic resistance is important in comparison with that of the tap. This is why such a control method is limited to the balancing of first level valves arranged in series with emitters of very low hydraulic resistance such as radiators or certain convectors. This considerably limits their use as these first-level valves are rarely accessible in occupied buildings. The object of the present invention is to propose a balancing method that is applicable to first and second level valves in series with emitters whose hydraulic resistance can be significant and impossible to determine. This is for example the case of non-removable elements, difficult or impossible to measure or calculate due to the frequent absence of distribution plans and internal fouling networks over time, hydraulic resistors such as those of columns or supply lines for transmitters, heating or cooling coils, sanitary circuit loops, etc.) This method must also prevent the user the strain of using special valves for measuring flow rates, or the implementation of surveys and complex calculations. The subject of the present invention is thus a method for balancing a water circulation heating / cooling installation comprising at least one series of at least one emitter disposed in a bypass between an upstream water supply pipe and a downstream return pipe, each series being individually adjustable by at least one first-level balancing valve characterized in that it comprises the steps of: measuring the temperature (T _A ) of the supply pipe (1) upstream of the series, and determining the difference in temperature, or reference difference (dt _re f), between this temperature (T _A ) and a temperature (T _B ) equal to either the temperature of the return pipe (3) upstream of the series is a temperature equal to the desired temperature for this pipe, - successively measure the temperature at the output of each of the emitters or set of emitters of the series, - d successively determine, for each series, the difference between the temperature upstream of the first series and the outlet temperature of each series, or specific deviation, establish, for each series, a correction coefficient equal to the difference between the value of the reference deviation with a value constituted by the product of an adjustment coefficient by the difference between the aforesaid value of the reference difference and the aforesaid value of the difference specific, - establish for each series a relative flow coefficient equal to the ratio of the reference difference on the corrective coefficient of measurement It is known that, properly sized, a flow control valve must have, in large opening, a authority of at least 0.5 on average and included, within customary limits, between 0.33 and 0.66, (authority defined by the ratio of the hydraulic resistance of the large open tap to the sum of the hydraulic resistance of the large tap open circuit and that of the circuit which he is responsible for regulating the flow). As a result, it has been established that it can be assumed that the hydraulic resistance of the networks on which the flow rates are to be adjusted can be considered as hydraulic resistance equal on average to the hydraulic resistance of the flow control valves of the same diameter. representative of those available on the market in position of large opening and limit between 50% and 200% of this hydraulic resistance. Accordingly, it can be taken into account, in series with the balancing valves, such a hydraulic resistance. This results in a correction of the relative flow variation q% _Rn of a valve of a given brand and type as a function of the number of revolutions N of its regulator and this for a constant pressure difference, correction defined by:

With: • q _vN : Flow in m ³ / h of the tap of the given brand and type for a number of N-turns, under a pressure Δp in Pa, installed in series with a hydraulic resistance that can not be dismantled, impossible or difficult to compute

• q _v ι _N : Flow rate in m ³ / h of the valve of the mark and of the type given for a number of turns N, under a pressure Δp in Pa, as indicated by the manufacturer or as measured on a hydraulic bench

• Δp: Determination pressure of q _v iN in Pa • kl: coefficient of adjustment of the authority, of 1 on average and between 0.5 and 2.

• Kv _s : Flow rate in m ³ / h under 10 ⁵ Pa of the most representative balancing valves on the market in the large open position, with: For valves from DN 10 to DN 50: 1 ηη Kv, = - + 9 , 83 x DN + 1.39.10 ^"21 x ^m - 47.23 ^s DN

For valves from DN 65 to DN 300:

Kv _s = 0.016 x i> V ² - L14.10 ^"128 xe ^m , r" - 0.54

An embodiment of the present invention will be described below, by way of nonlimiting example, with reference to the accompanying drawings in which: FIG. 1 is a schematic view of a water circulation heating installation hot line comprising a series of n sets of transmitters disposed in a shunt between a water inlet pipe and a return pipe. FIG. 2 is a curve representing an example of variation of the flow rate of a valve of nominal diameter 25 mm as a function of the number of turns thereof, in the direction of opening, under a constant pressure difference, of 10 ⁵ Pa, as supplied by its manufacturer or measured on a hydraulic bench. FIG. 3 is a curve representing the corrected variation in the flow rate of the 25 mm nominal diameter tap defined in FIG. 4 installed in series with a 25 mm nominal diameter supply circuit, with a high non-removable, difficult or impossible hydraulic resistance. to calculate or measure, as a function of the number of revolutions, in the direction of opening, under a constant pressure difference p of 10 ⁵ Pa. FIG. 4, identical to FIG. 3, is a curve representing the corrected variation of flow rate of 25 mm nominal diameter tap defined in Figure 4 installed in series with a circuit of 25 mm nominal supply diameter, high hydraulic resistance not removable, difficult or impossible to calculate or measure, depending on the number of turns in the direction of opening, under a constant pressure difference ρ of 10 ⁵ Pa. FIG. 1 shows a heating installation comprising a hot water supply pipe 1 and a return pipe 3. Several series Ri, R ₂ , R ₃ ,... R _n of emitters E ₁ , E ₂ , E ₃ , ... E _m , respectively are arranged one after the other, in parallel between these two pipes 1 and 3, and each of these series R _n emitters is equipped at the output of a tap ROi , R0 ₂ ... RO _n , said second level, to adjust the flow of hot water through it. In practice these emitters E _m may consist of radiators, convectors, or heating or cooling batteries as well as pipes and other elements associated with them which possess a significant unknown hydraulic resistance in comparison with that of the tap which is associated with this set. We are thus in setting conditions that are very different from those where we adjusted several series consist of a single radiator. The balancing operation of this installation consists in ensuring that the specific bit rate of each of these series R _n of transmitters is in correspondence with the respective powers. For, according to the invention, to put in equilibrium state such an installation, one proceeds as indicated hereinafter. It will first be noted that all the temperature measurements carried out in the context of the implementation of the balancing method according to the invention will preferably be carried out by means of thermometers capable of possessing a quasi-inexistent thermal inertia and a capacity to provide accurate and instantaneous measurement, such as infrared thermometers. Prior to the measurements, the balance control valves bodies RO _n associated with each Series R _n transmitters will preferentially arranged ent position mid-hydraulic opening. It has been established that the hydraulic mid-opening is defined by the setting position allowing a relative flow increase or decrease of the same amplitude. This mid-hydraulic opening can be very clearly different from the mid-mechanical opening when the control valve is in series with a significant hydraulic resistance in comparison with that of the valve. According to the invention, firstly, using an infrared thermometer, the temperature T _A of the pipe 1 is measured at a point A which, in the diagram of FIG. located upstream of the connection of the first series Ri of transmitters, and the temperature T _B of the pipe 3 at a point B, located downstream of the connection of the series Ri of transmitters. We can thus calculate the value which will be referred to below as the "reference gap". Then, also by means of an infrared thermometer, the temperature ts _n of the pipe situated at the outlet of each of the series R _n of emitters are measured. It has been established essentially empirically that the relative flow rate Q% _n of a given series of transmitters R _n (i.e., the percentage of the initial flow rate of this radiator with respect to its flow rate "to be adjusted" ) could be expressed as a function of the reference deviation and the temperature ts _n of its outlet pipe.

In this formula the coefficient k, called "adjustment coefficient", is taken in a first adjustment cycle to a value close to 1.5. It has indeed been found by the many measurements and tests carried out that if, after a first adjustment, it appears that the quality of the balancing obtained is not satisfactory, a second adjustment cycle can then be carried out in then taking a value of this coefficient of adjustment k weaker, then close to 1.1. Hereinafter will be described, with reference to FIG. 1, an exemplary implementation of the invention.

EXAMPLE In this example, the installation comprises a hot water supply pipe 1 and a return pipe 3 between which three series Ri, R ₂ , R ₃ of emitters E _n are connected in shunt. A temperature of the supply line 1 at the top of the series is measured at the point A of T _a = 60 ° C. and a temperature of the return line 3 at the point B of T _B = 50 ° C., as well as the temperatures at the output of the series of emitters Ri, R ₂ and R ₃ which are respectively tsi = 54 ° C, ts ₂ = 49 ° C and ts ₃ = 45 ° C. This gives a reference difference of _ref = 10 ° C. For the R _x series of emitters, the calculation according to formula (2) is then carried out and the following are obtained:

The relative flow rate Q% R1 obtained for the series of emitters Ri being 250%, this means that the initial flow rate of this series of emitters is 2.5 times too high and that, consequently, it will have to be reduced in a same ratio of 2.5 and thus close the control valve ROi so that its flow rate is divided by 2.5. The same will be followed for the series of R ₂ emitters:

¹⁰ 100 = 87% _{Q% R2 =} 10-1.5. [10- (60-49)] Since the relative flow rate Q% _R2 obtained for the series of issuers R ₂ is 87%, this means that the initial throughput of this series of transmitters is the 87/100 of what it should be and that, consequently, its The flow rate should be increased in a ratio of 100/87 = 1.15 and the control valve R0 ₂ must be opened so that its flow rate is multiplied by 1.15. Similarly for the series of emitters R ₃ we get:

10 100 = 57.1% Q R3 _Œ ° 10 to 1.5 [10 - (60 - 45)].

This means that the regulating valve R0 ₂ must be opened so that its flow rate is multiplied by 100 / 57.1 = 1.75. When it happens that the relative flow obtained Q% _RΠ is either negative or infinite, it is considered that the initial flow rate is infinitely large and that, consequently, the adjustment of the corresponding RO _n valve must be set to its minimum setting position. . In order to carry out this operation, for each of the series of emitters R _n , in an easy and fast way, curves are available which express the variation of the flow rate qv _N of the tap RO _n of the mark and of the type given as a function of the number of turns. of its adjustment member and this for a constant pressure difference. Such a curve, which can be supplied by the manufacturer or measured on a hydraulic bench, is shown by way of example in FIG. 2, for a nominal diameter of 25 mm of a tap of 8 T, measured under a pressure of 10 ⁵ Pa

It has been established, essentially empirically, that these values should be subject to a weighting. For the valve RO _n, the correction calculation according to formula (1) previously mentioned is carried out:

on which

Qv ₂ = 3.02 ΛH ³ Ih 1 1 ^• + • ^[ 3,2x3,2 1x1x9 ' By plotting these values on the curve of figure 2 one obtains a curve (a) which is under the curve (b) (figure 3). For each of the valves ROχ, R0 ₂ and R0 ₃ , the initial setting position of the valve is known. It will be assumed that initially the valve was half-open hydraulically which corresponds on the curve of Figure 4 to a position called 2.25 turns (N = 2.25) and at a rate of 3 , 3 m ³ / h, that is to say a position obtained from the closure taken as reference and then opening the valve 2.25 turns. The first set of emitters Ri whose flow rate is to be reduced in a ratio of 2.5 must therefore be brought to a flow rate of its ROi tap of 3.3 / 2.5 = 1.3 m ³ / h and the curve of FIG. 4 shows us that this flow is obtained for a position Nι = 0.87 of the tap ROi. Under these conditions, to bring this valve half of the hydraulic opening at this position 0.87 opening turns we will be forced to close a value of 2.75-0.875 = 1.87 turns. It is the same for the series of emitters R ₂ , whose flow must be increased in a ratio of 1.15. The flow rate of the associated valve R0 ₂ should be brought to a flow rate of 3.3 ^χ l, 15 = 3.8 m ³ / h and the curve of Figure 4 shows us that we must turn the control of this valve R0 ₂ to bring it to a position N ₂ = 2.75 turns of opening. It is the same, of course for the series of emitters R ₃ , whose flow must be increased in a ratio of 1.75. The flow rate of its valve RO3 should be brought to a flow rate of 3.3x1,75 = 5,77 m ³ / h and the curve of Figure 4 shows us that it will be necessary to bring the valve to a position N ₃ = 5 37. It will be necessary to close the tap of 5, 375-2, 25 = 3, 12 rounds. ^• It was found that once the adjustments were made the installation was balanced or almost balanced. However in some cases of adjustment it may be necessary to perform a second adjustment cycle. We then implement a process identical to that previously described but then retaining a value of the coefficient k that the tests and tests carried out showed that it should be lower and close to 1.1. When it turns out that the valve was first setting too closed or too open, the coefficient of authority ki is corrected by increasing it with the upper limit a value of 2. When it turns out that the valve was first adjustment insufficiently open or insufficiently closed, it corrects the coefficient of authority ki by decreasing it with low limit a value of 0.5. The method according to the invention can be implemented manually by carrying out the calculations mentioned above. However it will be easier to control by using a device to guide the user during the process and to automate some of the operations including calculations. Although the examples described in this application relate to a water-circulating installation by which the room is heated, all the operations could also be carried out in the event that this water-circulating installation would convey water. cold water to cool said room.

Claims

1.- Method for balancing a water circulation heating / cooling installation comprising at least one series (Ri, R ₂ , R _n ) of at least one emitter (Ei, E ₂ , E _n ) arranged in branching between an upstream water supply line (1) and a downstream return line (3), each series being individually adjustable by at least one first level balancing valve (ROi, R0 ₂ , RO _n ) characterized in that it comprises the steps of: measuring the temperature (T _A ) of the supply pipe (1) upstream of the series, and determining the difference in temperature, or reference difference (dt _ref ), between this temperature (T _A ) and a temperature (T _B ) equal to either the temperature of the return pipe (3) upstream of the series or a temperature equal to the desired temperature for this pipe, - successively measuring the temperature, (ts _n ) at the output of each of the transmitters or together of emitters (R _n ) of the series, - successively determining, for each series, the difference between the temperature (T _A ) upstream of the first series and the exit temperature (ts _n ) of each series, or specific deviation , for each series, establish a correction coefficient (A) equal to the difference between the value of the reference difference (dt _ref ) and a value constituted by the product of an adjustment coefficient (k) per the difference between the aforesaid value of the reference difference (dt _ref ) and the aforementioned value of the specific deviation, establish for each series (Ri, R ₂ , R _n ) a relative flow coefficient (Q% _n ) equal to the ratio of the reference difference (dt _rβf ) on the measurement correction coefficient (A).

2. A process according to claim 1 characterized in that the adjustment coefficient (k) is close to 1.5 during a first adjustment cycle and close to 1.1 for the following possible adjustment cycles.

3. A process according to one of claims 1 or 2 characterized in that one corrects the flow rate supplied to a series (R _n ) determined by multiplying its flow rate by the inverse of the relative flow coefficient.

4. A process according to claim 3 characterized in that one ensures the positioning of the valve adjusting member (R0 _n ) to be adjusted, with reference to the hydraulic response of this valve under constant pressure, corrected resistance series hydraulic according to the formula:

OR q _vN : is the flow rate in m ³ / h of the valve, q _v ι _N : is the flow rate in m ³ / h of the valve as indicated by the manufacturer or as measured on a hydraulic bench, Δp: is the determination pressure of q _v ι _N in Pa kl: is the coefficient of adjustment of the authority, Kv _s : is the flow rate in m ³ / h under 10 ⁵ Pa of the balancing valves most representative of the market in position great opening.

5. A process according to claim 4 characterized in that, when it turns out that a valve was first setting too closed or too open, it corrects the adjustment coefficient of the authority ki associated with that- by increasing it with a high value of 2.

6. A process according to claim 4 characterized in that when it turns out that a valve was first not sufficiently open or insufficiently closed setting, it corrects the authority coefficient ki associated with it by decreasing it with for low limit a value of 0.5.