DE2220598A1 - Method for regulating the humidification of an air stream blown into a room - Google Patents

Description

Ba 2120

CENTER SCIENTIFIQUE et TECHNIQUE du BATIMENT, Paris / France

and .

COMPAGNIE ELECTRQ-MECANIQUE, Paris / France

'Procedure for regulating the humidification of one in one , Room blown air flow

The invention relates to a method for regulating the humidification of a particular one blown into a room Air flow. The invention is based on the object of providing a pleasant interior with the lowest operating costs to achieve relative (air) humidity.

In the range between 30% and 60% , the degree of humidity has practically no effect on well-being, provided the air temperature does not exceed 2k ° , ie as long as there is no condensation.

In order to limit the heat consumption required for water evaporation during heating, efforts are made not to exceed a moisture content of J> 0% when the air has to be humidified. This can be achieved by setting the weight of the water in the air flow if the room temperature is fixed.

Let us assume, for example, an apartment with k rooms and tightly closed windows, which is mechanically ventilated, with a complete air change per hour. Then put the water weight at 5 g per kg.

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dry air, the following humidity conditions are obtained on average:

Without employment of people
in these rooms (5 g Water) % t _± = 23 °
t _± = 20 ° 28
34 Water)
%
% If you work for a longer period of time
4 to 5 people
ti = 23 °
ti = 20 ° (7 g
40
48

These conditions are very acceptable; no further moistening is required.

In the heating season is used by the residents of a larger Building a minimum, not an average, moisture content is desired * This therefore results in a requirement for a minimum water weight that should not be exceeded if further humidification is required.

The regulation described below fixes such a minimum water weight in the air flow, but enables a comfortable humidity level inside the rooms; The specified amount of water depends on several parameters (amount of air flow, ¹ tightness of the windows, internal release of water vapor, etc.).

When cooling takes place in summer, the air dries out because part of its water vapor on the cooling elements condensed. For reasons of comfort, however, a moisture content of 6OJG should not be in the rooms are undercut. It is possible to recover cooling energy by removing it from the cold cooling elements Air is humidified again. The maximum return

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Extraction corresponds to a moisture content in the interior of the rooms in the order of magnitude of βθ%, - This means that at an internal temperature of 24 °, the amount of water in the air flow is set at 11 g.

If a supplied air flow is humidified in living rooms (as in the case of air-conditioned rooms, in particular in offices), one is usually content with guiding the air flow through a humidifier and in this way to produce a moisture content between 30 and 60 #.

A very precise control of the humidification results in considerable savings in operating costs; such Regulation is absolutely necessary for electrical heating, for example. The importance of such a regulation is also greater, the better the insulation. With large amounts of air (as is the case with heat pumps between the supplied and extracted air) the savings achieved by such a control are extraordinary great.

On the other hand, the method according to the invention can be used in can be used in all cases in which the amount of water in an air stream must be determined, for example in Laboratories, industrial rooms, etc.

Known regulating devices use probes that directly measure the humidity of the air (relative Humidity, damp temperature or dew point temperature). These probes have numerous disadvantages and are often part of test facilities. Their reliability and sensitivity will be considerably increased

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Pollution disturbed, which requires frequent maintenance. In contrast, in the method according to the invention only uses probes that measure dry air temperatures, furthermore one probe that measures a water temperature.

Regardless of their level of contamination, these probes measure the respective temperatures precisely when the The temperature change does not occur too quickly (a requirement that is met). These probes therefore require only a reduced maintenance that does not go beyond the maintenance that is usually required for facilities for Regulation of a building heating provides anyway.

A control method was also investigated, which in its result of the efficiency of the humidification and its development (pollution or any other cause) is independent.

The control method according to the invention essentially consists in that the amount of water in the air stream is determined according to a given weight ratio in consideration of information provided by probes, the dry air temperatures and water temperatures measure up.

This control method can also use the dry temperature of the outside air.

These and other features and advantages of the invention will become apparent from the following description of some with reference the drawing of illustrated embodiments. These exemplary embodiments relate to the case of a heater; the The principle can also be used in the same way for cooling.

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- 5 -
In the drawing show:

Fig.la and Ib facilities shown schematically

to carry out the method according to the invention;

Fig. 2 to 6 representations of the moisture diagram

grammes, where the abscissa is the dry temperature of the air in degrees Celsius and the ordinate shows the weight of water in g per kg of dry air is. The oblique straight lines in these drawing figures, which represent the representative air point in the course of humidification follows, are curves of equal moist temperature (very close to the curves of equal entalpy). In detail

Fig. 2 delimits three zones 1, 2 and 3

FIGS. 3a and 3b give frequencies of pairs of dry temperatures and amounts of water the outside air in the Paris area and at the exit of a heat exchanger with an efficiency from 50/8.

Figs. ^ A and ^ b are diagrams for the case of a full saturation show the regulation of the amount of water in the air in different zones.

Fig. 5 is a diagram showing the arrival point curves as a function of the amount of water in the outside air the humidification for a humidifier with an efficiency of 8056.

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Pig.6a and 6b are diagrams for the case of a show incomplete saturation regulating the amount of water in the air in different zones.

To carry out the air humidification process according to the invention, the aeraulic arrangement shown in Pig.la or Ib is used. It contains a fresh air inlet opening 10, which continues in a line 11 in which a preheating device 12 may be arranged. The line 11 opens into a chamber 13, from which the air flow can either be directed into a line 13a, in which a humidifying device 1h is located, or into a line 13b, which bypasses the humidifying device 14 as a bypass. The lines 13a and 13b open into a mixing chamber 15, from which an outgoing line 16 leads to the rooms to be ventilated. The amount of fresh air optionally passed through the humidifier Ik is controlled either (Fig.la) by two oppositely acting flap systems 17a, 17b controlled by a motor 18 or (Fig.Ib) by a single flap 17c or controlled by a motor 18a by any other suitable system. These devices can be arranged either on the input side or on the output side of the lines 13a, 13b.

The dryer temperature T of the air at the outlet of the humidifier, the water temperature TE of this humidifier and the drying temperature T _{m of} the air are measured after a possible mixing of the humidified air supplied through line 13a with a certain amount of non-humidified fresh air supplied via line 13b.

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In certain cases, the dry temperature T of the outside air is also measured.

The temperature TE of the water of the humidifying device corresponds to the wet temperature with good accuracy the air that passes through this humidifier when the non-evaporated water is returned becomes when the circulating water. amount is not too large compared to the vaporized Amount of water and if finally the phenomenon of humidification is thermally well insulated (one can for example take the water temperature of the well-insulated trough).

In the humidity diagram of FIG. 2, the drying temperatures of the air are on the abscissa and the ordinate the amount of water in g per kg of dry outside air is applied. A horizontal straight line corresponds to the desired amount of water x. The inclined straight line in this diagram is the curve of the same wet bulb temperature, which by means of the dew point A, the desired amount of water χ runs; T- is

SO

the temperature of this dew point. These two straight lines limit three control zones 1, 2 and 3 in the diagram

In zone 1, the amount of water in the outside air is less than the desired amount; the wet temperature T "of this air is lower than the wet temperature T" _Q (T _un = T) of point A; to get this amount of water into the

riU SO

Introducing air requires preheating.

In zone 2, the amount of water in the outside air is less than the desired amount; the wet temperature T _{H of} this air is, however, greater than the wet temperature T " _o of point A (T ^ -. = T); this amount of water can be introduced into the air without preheating it.

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Zone 3 is the amount of water in the outside air. greater than the desired amount; is a humidification not mandatory.

The digram of Fig.3a showing the saturation curve shows, gives the frequencies of pairs of dry temperature-amount of water in the outside air in the Paris area. These are mean daytime conditions, whatever the location explained some points outside of the diagram. You can see from this diagram the relative importance of each Control zone depending on the value of the desired amount of water χ (especially in the case of χ = 5 g).

The diagram in FIG. 3b shows the frequencies of these pairs at the outlet of a heat exchanger with an efficiency of 50%. It can be seen from this that zone 2 is very important (especially when x = 5 g).

Regardless of whether or not there is a heat exchanger, it is also possible to only use zone 2 and 3 to provide a regulation in that all points of zone 1 are transferred to zone 2 by preheating which takes place, for example, as a function of the external drying temperature T. This preheating can be very be done precisely by taking into account the most frequent amount of water in the control for a given external drying temperature will.

The regulation of the amount of water in the air is different for each zone.

In the case of complete saturation, i.e. with an efficiency of the humidification of 100 $, the control procedures are as follows:

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In zone 1 (Pig. ¹ Ia) the outside air supplied is represented by point E and must follow the path EPA in order to obtain the desired amount of water χ * Point A represents the air at the outlet of the humidifier 14. During this process the line 13b is closed by the flap system 17b or the flap 17c, and T = T ". The preheating represented by the web EP takes place by regulating the device 14 in such a way / that T _m = T or T = T _Λ ( ¹ T is the

¹ ΙΠ SO S SO SO

Dew point temperature at the desired amount of water x).

In zone 2 (Pig.4b) the outside air is represented by point E; the humidification takes place at a constant wet temperature along the straight line EC. The air leaving the saturator is represented by point C; it is a matter of obtaining the mixture B with an air which has the desired amount of water χ and whose drying temperature T is. The air which leaves the saturation or humidification unit 14 is therefore mixed by setting the opening of the flap systems 17a, 17b or the position of the flap 17c with a certain amount of non-humidified fresh air supplied via the line 13b so that the desired Temperature T _{m is} reached.

This temperature T is obtained in the following way:

In zone 2, the wet temperature curves can approximately be replaced by a parallel network and the Saturation curve through the section of a straight line. It then results:

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^T m-

^T m-

T - T = DB = CD T ob ms g

V- ^T so = AD = CD T _g ß

'S

T _g ß

T = s

- T

SO'

T t

^T s -

so

T-T m so

1 +

T-T

S SO

^T _S -

It is, for example, K k 2.2 with a desired amount of water of 5 g.

Since T = TE, T can be replaced by TE in the above equations.

One comes from zone 1 to zone 2 as soon as the preheating becomes zero or as soon as T _{n is} less than T;

S SO

you get from zone 2 to zone 1 as soon as T is smaller

as T becomes. With each transition there is one or the other so

other regulation switched on.

No humidification is required in zone 3; the flap system 17a is completely closed; one therefore no longer knows the temperature T, which is either directly

is measured or by the Viassertemperature TE of the humidifier in operation. To _{know T o} or TF and to know whether humidification must occur, if

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if the amount of water decreases, the flap system will 17a fully opened for a few minutes (depending on the type of humidification or saturation device, generally less than ten minutes), at regular intervals (every η hours, since the amount of water in the outside air changes very slowly over the course of a day). ·

The humidifying devices generally have a limited degree of effectiveness. The diagram in FIG. 5, in which the drying temperatures of the air in degrees Celsius are plotted on the abscissa and the amount of water in g per kg of dry air is plotted on the ordinate, gives different amounts of water in the outside air (1 g, 2 g, 3 g, ^ g> 5 g) the curves P ₁ , P-, P ,, Ph and Pp- of the arrival points of the humidification for a humidification device with an efficiency of $ 80. In the event of such incomplete saturation, the individual zones are regulated as follows:

In zone 1 (FIG. 6a), in the case of fresh air with yg of water per kg of dry air, it is necessary ^{to follow the path EF 1} A 'and not EFA in order to achieve a fixed predetermined amount of water χ after humidification; Here, A ^{1 is} the intersection between the horizontal straight line, which corresponds to the desired amount of water χ, and the curve P of the point of arrival of the humidification in air, with yg V water and an efficiency of humidification of N %. The dry temperature of the air corresponding to this point A ¹ is T ¹

so

The preheating must therefore be regulated so that one receives:

T = T ^! or T = T '. m so s so

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- 12 Depending on the required accuracy, one can:

- Either ^{change T 1} depending on the drying

so

temperature T of the outside air by taking the value T 'corresponding to the amount of outside water, what the best accuracy and the lowest operating costs of the humidification device for every outside temperature results,

- or one can take a single value T ', which

so

corresponds to the mean external amount of water, which results in the best accuracy and the lowest operating costs of the humidifier.

In zone 2 (FIG. 6b), outside air containing ζ g of water per kg of dry air is represented by point E; their humidification takes place at a constant wet temperature along the straight line EC. The air that emerges from the humidification device (efficiency N %) is represented by point C at the intersection of the straight line with the same dampening temperature of point E and curve P ,, the arrival point of humidification for air with ζ g of water and an efficiency of Humidification of N %. To limit the amount of water in the air stream to the desired amount of water x, one must prepare the mixture represented by B, containing the desired amount of water χ and a drying temperature of T. The air emerging from the humidification device 14 is therefore mixed with a certain, non-humidified amount of fresh air, which is supplied via the line 13h, the opening of the flap systems 17a ₃ 17b or the flap 17c being controlled in such a way that the desired temperature T is obtained .

2 0 9 8 4 7/0 7 5 8

To reach the temperature T, there are two methods

m '■

possible:

First procedure:

The curves of the arrival points can be allowed to form a Humidification (with constant, limited efficiency) depending on the amount of water in the outside air are parallel (Pig * .5.). and the mixture is regulated according to the equation:

T_ φ f » xr I / rp'f ■ vn f \
m so · s so

Here you choose T ¹ as in zone 1.

You go from zone 1 to zone 2 as soon as the preheating is zero or as soon as T '> T 'and from the zone

s ^ so

into zone 1 as soon as T '<"T ¹ .

* S ^ SO

Second method:

A second method is the humidification temperature T " of the air "that passes through the humidifier.

It has already been said above that the water temperature TE of the humidifier can be accurately measured if this is not the case, this is the same as this Puchter temperature T ' evaporated water is returned if the amount of water in circulation is not too large compared to the evaporated amount of water and when finally the phenomenon of humidification is thermally well insulated (one can for example take the temperature of the water of the well-insulated trough).

209 847/0 7 53

Since this wet temperature T "(= TE) is equal to the temperature T at the output of a humidifier with an efficiency of $ 100, the triangle ABC is known and one can determine the temperature T according to the following relationship:

^T m - ^T so = ^{K. (TE} - ^T so>

for example with K 4 2.2 for a desired amount of water of 5 g.

This temperature TE of the water in the humidifier is independent of the efficiency of the humidifier. As a result, this second method enables to achieve precise control in zone 2 regardless of this efficiency and its development.

You get from zone 1 to zone 2 as soon as the Preheating becomes zero or as soon as TE 3 · T and from zone · 2 into zone 1 as soon as TE <. T. With each transition, it becomes

SO

one or the other regulation switched on. This second method is therefore quite precise and particularly appropriate, if a heat exchanger is provided (Fig.4b); this is where most of the points are, which the fresh air represent, in zone 2.

Making the advantages of this second procedure interesting appear to suppress the points of zone 1 by preheating by removing all points that are without Preheating are located in zone 1, are transferred to zone 2. This preheating can depend on the outside temperature can be regulated, taking into account the amount of water that occurs most frequently for each temperature.

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If the conditions of the outside air are in zone 3, for which no humidification is required, one leaves as explained for the case of full saturation, in order to determine when humidification should occur Has.

In the case of cooling in summer, the air is naturally heated to achieve the desired level Amount of water not taken into account. The moistening then takes place up to the maximum for the points of zone 1, without you can achieve the desired amount of water. A regulation, i.e. a limitation of the humidification, only takes place for the points located in zone 2; the control procedures in this zone 2 are the same as in zone 2 for heating.

The transition to zone 2 and the triggering of the control therefore take place as soon as TE> T or T> T

SO S SO

or T ' _s >T' _so .

If you are in zone 3, where you have to avoid humidification, which increases and increases the amount of water leads to uncomfortable moisture levels, so go as in the case of heating, to determine when the amount of water decreases and to start humidifying again Has.

As for the accuracy of the temperature measurement in the case of saturation of $ 100 when points A and C are fixed the fault is the airborne V / assermenp-e (in p) pep through (vpl.Fip.'lb):

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- 16 - = Δ CD = Δ DB

In order to achieve an error of the order of 1/5 g, errors of 1/10 ° _{can therefore be allowed at most in the measurement of T m} and T _0.

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Claims (1)

2220599 - 17 claims . l.j method for regulating the humidification of an air stream, characterized in that the amount of water in the air stream is determined according to a given quantity or weight ratio taking into account information provided by probes that measure dry air temperatures and water 'temperatures. 2. The method according to claim i, characterized in that the preheating of an air stream before it passes through a humidifier is regulated. 3. The method according to claim 1, characterized in that the possibly preheated amount of air is regulated optionally routed via a humidifying device and a line bypassing this humidifying device will. k . Process according to claims 2 and 3 »characterized in that the preheating and the mixing of humidified and non-humidified air are regulated as a function of the drying temperature T of the air flow ti before preheating and humidification, from the drying temperature T or T 'of the air flow at the outlet of the 5 p humidifying device, from the temperature TE of the water of the humidifying device, from the drying temperature T of the air after a possible mixing of part of the humidified air flow and the non-humidified air flow Partial flow. 209847/0758 5. The method according to claim 4, characterized in that the humidifying device is designed or »is operated that the humidification process is thermal
is isolated by recirculating non-evaporated water and reducing the amount of water in circulation, such that the temperature TE des
Water of this humidifier equal to the
Moisture temperature of the prevailing this facility
Air flow is, which in turn is equal to the dry temperature T_ of the air flow at the outlet of a humidifier, which causes complete saturation. 6. The method according to claims 4 and 5, characterized - draws that the dry temperature T SO of the dew point according to the desired amount of water and with the test temperature T _HQ . 7. The method according to claims H and 5, characterized in that when using a humidifying device with incomplete saturation as a reference
Temperature T ^{1 is} used, namely the dry temperature of an air with a dry temperature T ^f " ₀ at the outlet of the
Humidification device containing the desired amount of water, this air being the same before humidification
The same amount of water as the air to be humidified. 8. The method according to claim 7, characterized in that when the amount of water in the air to be humidified fluctuates, a single value T ¹ , corresponding to an average amount of water that provides optimal conditions, is used. 209847/0758 9. The method according to claim 7, characterized in that when fluctuating the amount of water 'in the air T ¹ as a function of the dry temperature T of the "outside air varies by choosing the value T' corresponding to the mean external amount of water, which for each Outside temperature results in optimal conditions. 10. The method according to any one of claims 3 to 9, characterized in that when the wet temperature T _{u of} the air before humidification is less than T _x , -. or ■ ti xlU T ¹ J ₁₀ is, depending on whether the humidification device delivers complete or incomplete saturation, the air flow only runs over the preheating device, which is regulated in such a way that a temperature T _m or T _s (T _m - T _g ) is obtained, which is equal to T _go or T ' _sq , depending on whether the humidification device delivers complete or incomplete saturation. 11. The method according to any one of claims 3 to 9> characterized in that when the air stream contains an amount of water before preheating and humidification, which is smaller than the desired amount of water and look at a wet temperature T "greater than T" _Q or T '" _Q is located, the air flow is not preheated and is selectively routed over the humidifier and over a bypass line. 12. The method according to any one of claims 3 to 9, wherein the wet temperature T "is less than T" _o , characterized in that the air flow is preheated as a function of T. And that which occurs most frequently in the air before humidification The amount of water taken into account in order to achieve a wet temperature of at least equal to T " _Q. 209847/0758 13. The method according to claims 11 and 12, characterized in that that when the humidifier provides complete saturation, the mixture of the humidified and the non-humidified air happens as follows: T - T = 'K (T - T);
m so s so ' Here, K is a constant that depends on the desired amount of water. I ¹ J. Procedure according to the. Claims 11 and 12, characterized in that when the humidifying device results in complete saturation, the humidified and non-humidified air are mixed as follows: τ _T r κ (T -T )
• m so * ^U E so ^; ' Here, K is a constant that depends on the desired amount of water. 15. The method according to claims 11 and 12, characterized in that that when the humidifier provides incomplete saturation, the mixture of the humidified and non-humidified air happens as follows: φ _ φι = κ · f φ -Φ ¹ } ·
m so * ¹¹ S ¹ so ^; ' Here, K 'is a function of the desired amount of water and the efficiency of the humidifying device Constant. 209847/0758 16. The method according to claims 11 and 12, characterized in that that when the humidifier provides incomplete saturation, the mixture humidified and non-humidified air happens as follows: ^T m- ^T _S o = ^{K (T} E - ^T so>;' here K is one of the desired amount of water pending constant. Method according to Claims 10 and 11, characterized in that the preheating is suppressed and the air bypassing in relation to the humidifying device is regulated as soon as T _{g is} greater than T ₃₀ . 18. The method according to claims 10 and 11, characterized in that the air is preheated while air bypassing the humidifying device is suppressed as soon as T is less than T _so . 19. The method according to claims 10 to 12, characterized in that when the amount of water in the air is greater than the desired amount of water, the humidification takes place every η hours for a few minutes in order _{to determine the temperature T 0} or TE and thus determine whether humidification has to take place. 209847/0758 Blank page