FR2828557A1 - Controlled mechanical ventilation system for house has pressure sensitive switch controlling speed of extractor fan motor - Google Patents

Abstract

The ventilation system, consisting of a housing (2) with suction ports (3 - 7), an extractor fan and motor, and ducts (8) connecting the housing to the different rooms (12 - 14) of a house from which air is to be extracted and an exterior outlet, incorporates a pressure sensitive switch connected to a pressure detector inside the housing and controlling the extractor fan motor speed. The pressure detector has a probe located on the suction side of the fan and increases the motor speed when the suction effort drops below a set level, e.g. around 85 Pa, reducing the speed at about 120 Pa.

Description

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 The invention relates to controlled mechanical ventilation (VMC) groups which essentially equip the individual houses. It relates particularly, but not exclusively, the controlled mechanical ventilation groups called humidity sensitive.

 Figure 1 shows schematically a conventional ventilation system of a house with a group of mechanical ventilation controlled 1 placed in the attic of the house. The VMC group comprises a body 2 in the form of a generally cubic box. This type of VMC group is well known and will not be described in detail.

 The group VMC 1 comprises a motor-fan not shown which is arranged in the box 2. This is provided with several suction openings which in the illustrated example are five in number and of which only three 3,4 and 5 are used, the other two 6.7 being clogged. Flexible ducts 8 respectively connect the suction openings 3, 4 and 5 to extraction outlets 9, 10, 11 placed in the different service rooms from which the exhaust air must be sucked.

 The VMC group also has a discharge opening (not shown) that allows exhaust air to be discharged outside using an outlet located on the roof.

 In the example illustrated in Figure 1, the suction opening 3 is thus via the flexible conduit 8 connected to a bathroom 12, while the suction opening 4 is connected to a WC 13 and the suction opening 5 is connected to a kitchen 14. This installation thus makes it possible to extract stale air from these three technical parts.

 Of course, the suction openings can be connected to other service rooms such as a second bathroom, a second toilet, a laundry room, a storeroom etc., which is not the case in the example illustrated.

 The air enters the house through negative air inlets 15 placed on the windows of the main rooms, namely the living room 16 and the chamber 17. These air inlets can be either self-adjustable or humidity sensitive.

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 Generally, the extraction mouth 11 of the kitchen 14 is a mouth equipped with a hygrosensitive element controlling a flap (not shown) that opens or closes the air passage depending on the humidity. A second shutter (not illustrated) controlled manually or electrically allows to reach a peak flow during the preparation of meals. The operating range of this mouth 11 is generally between 80 and 160 Pa.

 In an example that applies to a dwelling with up to five main rooms, the flow rates from the kitchen 14 can be the following: - 10 m3 / h of minimum humidity controlled flow at a detected relative humidity of 12%; - 45 m3 / h maximum hygrocontrolled flow at a detected relative humidity of 45%; - 135 m3 / h at peak flow.

 The extraction mouth 10 of the bathroom 12 can also be a hygrosensitive mouth controlling a flap (not shown) that can open or close the air passage depending on the humidity. The following values can then be obtained for the extraction of the bathroom 12: - 5 m3 / h minimum hygrocommanded flow at a detected relative humidity of 30%; - 40 m3 / h maximum hygrocontrolled flow at a detected relative humidity of 65%.

 Regarding the WC 13, it is often equipped with an extraction mouth 10 with two flow rates manually controlled by pull or electrically, which gives for example the following values: - 5 m3 / h in closed position; - 30 m3 / h in open position.

 Generally, the VMC group is equipped with a single-speed fan motor operating continuously, capable of extracting the maximum flow of the extraction mouths, taking into account the probability that they are not all

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 open up at the same time. On the other hand, it is considered that the extraction mouths can simultaneously be in minimum flow position.

 These two constraints impose a particular characteristic curve making it possible to obtain a large flow with sufficient pressure available to overcome the pressure drops of the extraction network while guaranteeing the flow rate, and to go down to a very low minimum flow, while remaining quite low pressure so as not to generate noise at the extraction vents.

 The VMC groups currently on the market favor either the flow rate reaching at best 260 m3 / h for an available vacuum of 100 Pa with a permanent power consumption of 50W on average, or the power consumption, consuming 35 to 40W, but ensuring a maximum flow rate of 200 m3 / h for an available vacuum of 90 Pa, insufficient values considering the usual situation in the use of the extraction mouths. In the latter case, the average consumption can be about 40W.

 Figures 2 and 3 illustrate VMC groups belonging to one or other of these two categories.

 Thus, FIG. 2 shows a diagram of the values obtained during tests on a VMC group of the first category. The Pstat depression in Pa and the power consumption P in W are shown on the ordinate, on the left and on the right respectively, and the flow rate in m3 / h on the abscissa. In this figure, the curve (D shows the pressure as a function of the flow rate and the curve shows the power consumed as a function of the flow rate.

 Figure 3 shows a similar diagram of the values obtained in tests on a VMC group of the second category. With this group VMC, it is certainly possible to obtain a lower consumption corresponding to an average value of about 40W, but that provided that several extraction mouths are closed simultaneously, which is not always the case. In any case, the flow rate is also lower compared to the VMC group of the first category and the optimum flow rate can not be ensured in all situations of use.

 In summary, it can thus be seen that the existing VMC groups of the humidity-sensitive type operate continuously on a single speed which in principle must

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 correspond to the needs of maximum flow, the variation of flow being made only at the level of the extraction mouths.

 This requires limiting this maximum flow rate by applying a use regime that does not always correspond to the reality of the situation at the extraction vents, in order to limit as much as possible the ventilation performance of the motor-fan in order to reduce its power consumption, and not to rise too high in pressure when the flow is a minimum flow.

 Most of the time, when the humidity is average and the additional flow from the kitchen is not used, the fan will indeed be oversized compared to the needs. In addition, the fan motor rotating permanently at a relatively high speed, its service life is reduced.

 The invention aims to overcome these disadvantages by proposing a VMC group to greatly reduce the power consumed while operating automatically, without any intervention of the user, the only command available is the order of peak flow in the kitchen.

 The object of the invention is a controlled mechanical ventilation unit (VMC) capable of ensuring the extraction of stale air from a house, comprising a body provided with several suction openings and at least one opening downstream discharge respectively upstream of a motor-fan arranged in the body, the suction openings being intended to be connected to parts in which the suction must be performed, the discharge opening being intended to be connected outside the house, characterized in that it is furthermore associated with a pressure switch connected to means for detecting the depression inside said body, the pressure switch being connected to means for switching the speed of the fan motor between a low speed and a high speed according to a detected vacuum value, so as to switch to said high speed when the detected depression value falls below a value of d e predetermined depression, and vice versa.

 According to other characteristics of the invention: said pressure switch is integrated in the VMC group; the detection means comprise a probe disposed in the body, upstream of the motor-fan in the flow direction of the flow sucked into the group;

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- le groupe est du type dit hygroréglable ; - le groupe est du type non hygroréglable. the switching means are controlled directly by the pressure switch; - The switching means are controlled via a control device interfacing between the pressure switch and the switching means; the pressure switch is set in such a way that when the depression reaches a value of approximately 85 Pa 7 Pa, a control signal is sent to actuate the switching means in order to switch the motor-fan on said high speed, and when the vacuum reaches a value of about 120 Pa 7 Pa, a control signal is sent to actuate the switching means to switch the motor fan again on said low speed;

- the group is of the type said humidity sensitive; - the group is of the non-humidity-sensitive type.

 Other features and advantages of the invention will emerge from the following description of a non-limiting embodiment of the invention, with reference to the appended figures in which: - Figure 1 is a perspective view, partly broken away; , a house showing the layout of an extraction installation comprising a VMC group placed in the attic; FIG. 2 is a diagram illustrating on the ordinate the vacuum and the power consumed as a function of the flow rate indicated on the abscissa, on an extraction installation comprising a conventional water-regulatable VMC group; FIG. 3 is a diagram illustrating, on the ordinate, the depression as a function of the flow rate indicated on the abscissa, on another extraction installation comprising a conventional hydroregulated VMC group; and FIG. 4 is a diagram illustrating on the ordinate the vacuum and the power consumed as a function of the flow rate indicated on the abscissa, on an extraction installation comprising a group VMC according to the invention, at at least two speeds and provided with a pressure switch; - the fan motor of the group has a number of speeds equal to or greater than two.

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 FIG. 1, already described in the introduction, shows the framework for using a VMC group according to the invention. Like a conventional VMC group, it comprises a body 2 provided with several suction openings 3 to 7 on the front face of the group, and at least one discharge aperture which in the group VMC illustrated in FIG. back side of this group.

 According to the invention, the VMC group 1 is at least two speeds, one said a small speed and the other said high speed and is associated with a non-referenced pressure switch. This pressure switch is advantageously integrated into the body of the VMC group, that is to say placed inside the box forming the body of the group, and it is connected to means for detecting the depression inside the body 2.

 The detection means may comprise a non-referenced probe disposed in the body, upstream of the motor-fan in the flow direction of the flow sucked into the VMC group by the suction openings.

 The pressure switch is connected to means for switching the speed of the fan motor between the low speed and the high speed, depending on the detected vacuum value, so as to switch to the highest speed when the detected vacuum value falls below a predetermined vacuum value, and vice versa.

 The switching means preferably comprise a switch able to be controlled between several positions by a control signal generated directly by the pressure switch or by a control device interfacing between the pressure switch and the switching means in order to supply the control signal by function of the depression value calculated in the pressure switch as a function of the measured depression.

 Of course, the pressure switch itself can be outside the body of the VMC group while being connected to the depression detection means which themselves are inside the body.

Example
Tests have been carried out on a VMC group said moisture-sensitive suitable for use in a house with a kitchen, a first bathroom

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 SdBl, a second bathroom SdB2, a first toilet WC1, and a second WC2 toilet.

intermédiaire à 45 m3/h, alors que le débit à partir des salles de bain SdB 1, SdB2 variait entre 5 et 40 m3/h, et, finalement, le débit à partir de cabinets d'aisance WC1, WC2 variait entre 5 et 30 m3/h. The flow from the kitchen ranged from 10 to 135 m3 / h, with

intermediate at 45 m3 / h, while the flow from the bathrooms SdB 1, SdB2 varied between 5 and 40 m3 / h, and finally the flow from lavatories WC1, WC2 varied between 5 and 30 m3 / h.

The table below shows the values obtained, and also the flows for which the different speeds, here in number of two, were triggered:

<Tb>
<tb> Kitchen <SEP> SdBl <SEP> SdB2 <SEP> WC1 <SEP> WC2 <SEP> Qtot. <SEP> m3h <SEP> Speed
<tb> 10/45/13 <SEP> 5/40 <SEP> 5/40 <SEP> 5/30 <SEP> 5/30
<tb> 5
<tb> 10 <SEP> 5 <SEP> 5 <SEP> 5 <SEP> 35 <SEP> 1
<tb> 45 <SEP> 40 <SEP> 30 <SEP> 115 <SEP> 1
<tb> 45 <SEP> 40 <SEP> 40 <SEP> 30 <SEP> 5 <SEP> 160 <SEP> 1
<tb> 135 <SEP> 40 <SEP> 40 <SEP> 30 <SEP> 5 <SEP> 250 <SEP> 2
<Tb>

ventilateur tourne à la petite vitesse. De manière analogue, la courbe G) montre la dépression Pstat en Pa en fonction du débit, alors que la courbe (D montre la puissance consommée en fonction du débit lorsque le moto-ventilateur tourne à la grande vitesse. The diagram in Figure 4 shows curves illustrating the operating ranges and power consumed at low speed and high speed. Thus, the curve (D shows the Pstat depression in Pa as a function of the flow rate, while the curve (D shows the power consumed as a function of the flow rate when the motorcycle

fan runs at low speed. Similarly, the curve G) shows the Pstat depression in Pa as a function of the flow, while the curve (D shows the power consumed as a function of the flow rate when the fan motor rotates at high speed.

désignée"1"dans le tableau, qui était suffisante pour assurer les débits correspondant au débit maximum hygrorégulé de la cuisine, d'une ou de deux salles de bain SdB 1 et/ou SdB2, et d'un cabinet d'aisance WC1. La grande vitesse y est désigné"2". The VMC group operated most of the time (22h / 24h) in low speed,

designated "1" in the table, which was sufficient to provide the flow rates corresponding to the maximum humidity flow of the kitchen, one or two bathrooms SdB 1 and / or SdB2, and a toilet WC1. High speed is designated "2".

 Until this flow rate, the available pressure was greater than 85 Pa. When the depression reached this value of 85 Pa 7 Pa, the pressure switch sent a control signal to actuate the switching means to switch on the high speed of the motorcycle. fan, which allowed to increase the pressure

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 available and the flow if the extraction mouths opened, especially when the user operated the peak flow of the kitchen extraction mouth.

This high speed allowed to reach a flow of 250 m3 / h with a depression of 105 Pa.

When the mouths closed, the operating point then moved on the curve to the left, until reaching 120 Pa: 17 Pa, value which corresponds to the actuation of the switching means when they receive a control signal pressure switch (85 Pa + 35 Pa differential), which made switching the motor fan again at low speed, and so on.

 It can be seen from Figure 4 that the average power consumption when the engine was running at low speed was 21 W and that the average power consumption when the engine was running at high speed was 53 W.

 If we consider the power consumed in a conventional VMC group, we know that it consumes normally in the year: 50 W x 24h x 365j = 438kWh, while the VMC group according to the invention which has at least two speeds and which is provided with a pressure switch which directly or indirectly controls a gearshift, we obtain, considering the normal case where the motor-fan works 22h / day in low speed and 2h / day in high speed: [21W x 22h + 53W x 2h] x 365d 207 kWh.

 In this example, a reduction of the power consumption which is greater than 50% is thus obtained. For the individual consumer, this is already important, and considered on a national scale, this represents a significant reduction in the consumption of electrical energy.

 Thanks to the invention, one obtains in addition an extraction system operating automatically, without any intervention of the user.

 Of course, the invention is not limited to the example illustrated and described, but can be applied to any type of controlled mechanical ventilation system. Thus, even if the invention has been described in the example of a VMC group said moisture-sensitive, it can easily be applied to any conventional VMC group.

 The speeds can also be a number of three or four, see more, which allows more limited ranges for the passage from one speed to another.

Claims (9)

1. Controlled mechanical ventilation unit (VMC) capable of ensuring the extraction of stale air from a house, comprising a body (2) provided with several suction openings (3 to 7) and at least one discharge opening downstream respectively upstream of a motor-fan arranged in the body (2), the suction openings (3 to 7) being intended to be connected to parts (12 to 14) in which the suction must be performed, the reject opening being intended to be connected to the outside of the house, characterized in that it is further associated with a pressure switch connected to means for detecting the depression inside said body (2), the pressure switch being connected to means for switching the speed of the fan motor between a low speed and a high speed as a function of a detected vacuum value, so as to switch to said high speed when the value of depression detected falls below a predetermined vacuum value, and vice versa.  2. Controlled mechanical ventilation unit according to claim 1, characterized in that said pressure switch is integrated in the group.  3. Controlled mechanical ventilation unit according to claim 1 or 2, characterized in that the detection means comprise a probe disposed in the body, upstream of the motor fan in the flow direction of the flow sucked into the group.  4. Controlled mechanical ventilation unit according to any one of the preceding claims, characterized in that the switching means are controlled directly by the pressure switch.  5. Controlled mechanical ventilation unit according to one of claims 1 to 3, characterized in that the switching means are controlled by means of a control device interfacing between the pressure switch and the switching means.  6. Controlled mechanical ventilation unit according to any one of the preceding claims, characterized in that the pressure switch is set such that when the vacuum reaches a value of about 85 Pa 7 Pa, a control signal is sent for operate the switching means in order to <Desc / Clms Page number 10>  switching the fan motor to said high speed, and when the vacuum reaches a value of about 120 Pa: t 7 Pa, a control signal is sent to actuate the switching means to switch the motor fan again on said slow speed.  7. Controlled mechanical ventilation unit according to any one of the preceding claims, characterized in that the group is of the so-called humidity-adjustable type.  8. Controlled mechanical ventilation unit according to any one of claims 1 to 6, characterized in that the group is of the non-humidity sensitive type.  9. Controlled mechanical ventilation unit according to any one of the preceding claims, characterized in that the fan motor of the group has a number of speeds greater than two.