US20110023517A1

US20110023517A1 - Facility for producing sanitary hot water for congregate housing

Info

Publication number: US20110023517A1
Application number: US12/864,085
Authority: US
Inventors: Damien Labaume; Serge Buseyne
Original assignee: Aldes Aeraulique SA
Current assignee: Aldes Aeraulique SA
Priority date: 2008-01-22
Filing date: 2009-01-19
Publication date: 2011-02-03
Also published as: ES2774179T3; WO2009092976A3; PL2232155T3; FR2926626A1; WO2009092976A2; FR2926626B1; EP2232155B1; EP2232155A2; CA2712189A1

Abstract

The invention relates to a facility for producing sanitary hot water for congregate housing (1) that comprises a plurality of water heaters (2) each intended to equip a plurality of individual dwellings (2) in the housing (1). Each water heater includes a tank (3) containing a fluid to be heated, each dwelling (2) being further equipped with at least one air extraction duct (4), in particular in the technical rooms (5), connected to an air extraction network (8) that is common to the different dwellings (2). Each dwelling further includes a heat exchange means (10) adapted for exchanging heat between the extracted air flowing in the air extraction duct (4) and the fluid contained in the tank (3) so as to heat the fluid in order to produce sanitary hot water.

Description

TECHNICAL FIELD

The invention relates to a facility for producing sanitary hot water for congregate housing.

BACKGROUND

Given the environmental constraints and the high cost of energy, it is necessary to reduce the consumption of different facilities in housings. The needs of the facility for heating housings have been significantly reduced, in particular by the use of new insulation materials, the placing of adapted glazing and the reduction of thermal bridges during the construction of the building.
Similarly, the needs of a facility intended for the ventilation of the housing are significantly reduced by using a double flow ventilation, allowing to recover calories on the extracted airflow in order to transfer them to the injected airflow or by using a modulated ventilation, the operation of which is limited to actual and functional needs, for example, on the hygrometry rate inside the housing.
Presently, it is observed that, in the “low consumption” type homes, the facility intended for producing sanitary hot water is that which uses most of the energy.
It is therefore evident that it is necessary to reduce the energy needs of this type of facility.
For this purpose, it is known to use a facility for producing sanitary hot water comprising a water heater with a tank within which is stored fluid to be heated, and a controlled mechanical ventilation system intended to extract air from a housing, the controlled mechanical ventilation system being coupled to a thermodynamic circuit within which flows a coolant fluid, the thermodynamic circuit comprising an evaporator adapted for exchanging heat with the extracted air, a compressor, an expander and a condenser adapted for exchanging heat with the fluid contained in the tank.
Such a facility is generally designated by the term “thermodynamic water heater on the extracted air”.
Such a type of facility allows recovering part of the heat of the extracted air and transferring it to the fluid contained in the tank of the water heater, through the thermodynamic circuit and heat exchangers formed by the evaporator and the condenser.
However, the known facilities of this type are not suited for congregate housing.
For safety reasons related to the spread of fires, it is not possible to divert the extracted air from each facility in an extraction duct common to the various dwellings. Where such a facility was provided and in the assumption of a failure at the extraction point of one of the dwellings, for example in case of failure of a corresponding extraction fan, the phenomena of overpressure within the common duct could lead to a spread risk of smoke or fire inside the dwelling equipped with the failing fan.
It would then be necessary that each dwelling have its own air extraction network, which generates additional costs and/or a major difficulty of implementation.
There are other facilities for producing sanitary hot water, suitable for congregate housing.
For example, it is known using a centralised facility for producing hot water, equipped with a boiler connected to a distribution network capable of conveying sanitary hot water to the various dwellings. Such a facility must hence comprise at least a pump to flow the hot water
This type of facility is costly and it results in heavy thermal losses, since the hot water must flow over long distances in the distribution network, and in electric power consumption at the pumps too.
Another known facility is the congregate solar water heater. Such a facility comprises a common tank of water to be heated, from which extends a distribution network of sanitary hot water to the various dwellings. This type of facility has the same drawbacks as the previous facility.

BRIEF SUMMARY

The invention provides a facility for producing sanitary hot water suitable for congregate housing, inexpensive, and with an increased performance.
To this end, the invention relates to a facility for producing sanitary hot water for a congregate housing, characterised in that it comprises a plurality of water heaters, intended to equip a plurality of individual dwellings of the housing, each water heater comprising a tank within which is stored fluid to be heated, each dwelling being furthermore equipped with at least an air extraction duct, particularly in the technical rooms, connected to an air extraction network common to the various dwellings, each dwelling furthermore comprising heat exchange means adapted to exchange heat between the extracted air flowing through the air extraction duct and the fluid contained in the tank, so as to heat the fluid in order to produce sanitary hot water.
The sanitary hot water may be produced in each dwelling so as to limit the thermal loses due to the flowing of water over long distances.
In addition, the calories drawn from the extracted air allow heating of the fluid contained in the tank of the water heater, in order to increase the overall performance of the facility.
Finally, the fact that the extraction is carried out through an air extraction common network avoids the necessity to provide for ventilation means, such as fans, in each dwelling. In this way, the aforementioned overpressure phenomena within the extraction network are avoided and, consequently, the risks of fire spreading also.
According to a characteristic of the invention, the heat exchange means comprise a thermodynamic circuit, within which flows a coolant fluid, the thermodynamic circuit comprising an evaporator adapted to exchange heat with the extracted air, a compressor, an expander, and a condenser adapted to exchange heat with the fluid contained in the tank.
According to an embodiment of the invention, the condenser is located within the tank of the heater water, in order to exchange directly heat with the fluid contained in the tank.
According to another embodiment of the invention, the heat exchange means comprise a secondary circuit of heat exchange within which flows a coolant fluid, passing through the condenser so as to exchange heat with the coolant fluid, the secondary circuit furthermore comprising a heat exchanger located within the tank of the water heater, so as to exchange heat with the fluid contained in the tank.
According to a possibility of the invention, the facility comprises an air injection network common to the various dwellings, each dwelling being equipped with a heat exchanger of the double flow type, wherein the airflow injected into the dwelling and being drawn from the air injection network exchanges heat with the airflow extracted from the dwelling.
Using a double flow type heat exchanger allows reducing the thermal losses associated with the air extraction and recover part of the calories contained in the extracted air to heat the injected air in the dwelling.
Preferably, the heat exchanger of the double flow type is located upstream of the heat exchange means between the extracted air and the fluid contained in the tank, in the flow direction of the extracted air.
According to a characteristic of the invention, the facility comprises recycling means allowing directing part of the injected air from the air injection network, directly into the air extraction network, upstream of the heat exchange means in the flow direction of the extracted air.
The recycling means allow accelerating, should it be necessary, the airflow flowing through the heat exchange means, in order to promote heating of the sanitary hot water.
Preferably, the air extraction network, common to the various dwellings is equipped with at least one fan capable of carrying out the air extraction from each dwelling.
According to a possibility of the invention, the air injection network, common to the various dwellings, is equipped with at least one fan capable of carrying out the air injection from each dwelling.

BRIEF DESCRIPTION OF THE DRAWINGS

In any case, the invention will be better understood by using the following description, with reference to the attached schematic drawing showing, by way of not limiting examples, several embodiments of this facility for producing sanitary hot water.

FIG. 1 is a schematic illustration of a congregate housing equipped with a facility according to the invention;

FIG. 2 is a plan of a dwelling of the housing detailing the location of the various elements of the facility;

FIG. 3 is a schematic view of part of the facility, according to a first embodiment of the invention;

FIG. 4 is a view corresponding to FIG. 3, of a second embodiment of the invention.

DETAILED DESCRIPTION

A congregate housing 1 equipped with a facility for producing sanitary hot water is shown in FIG. 1.
The housing comprises a plurality of dwellings 2 distributed over several floors. Only one dwelling 2 per floor is shown in FIG. 1 for readability reasons.
Each dwelling 2 comprises a water heater comprising a tank 3 within which is stored a fluid to be heated.
Each dwelling 2 is furthermore equipped with at least an air extraction duct 4, in particular in the technical rooms 5, as better shown in FIG. 2.
In the case shown in FIGS. 1 and 2, the intake of air for a dwelling 2 is through the windows 6 and is extracted through extraction air vents 7 communicating with the duct 4, as shown by arrows. Therefore, the facility operates with a ventilation system of the single flow type.
The injected airflows and the extracted air shown in FIG. 2 are only given by way of not limiting example. It is understood that different embodiments may be considered.
The air extraction duct 4 of each dwelling 2 is connected to an air extraction network 8 common to the various dwellings, the air extraction network 8 comprising an upper part equipped with a fan 9.
In addition, each dwelling 2 comprises heat exchange means 10 adapted to heat the fluid contained in the tank 3 from the extracted air flowing through the duct 4.
According to another possibility of the invention, an air injection network 11 common to the various dwellings (FIGS. 3 and 4), is equipped with a fan. In this case, the injection and the extraction of air are controlled simultaneously. This is what is known as double flow type ventilation. In the case of double flow ventilation, air intakes are carried out, not any longer through the windows, but at the air inlet mouths located in the living rooms 12.
The structure of the heat exchange means 10 will now be described in more detail with reference to FIGS. 3 and 4, in the case of double flow type ventilation.
According to a first embodiment shown in FIG. 3, the heat exchange means 10 comprise a thermodynamic circuit 13 within which flows a coolant fluid.
The thermodynamic circuit 13 comprises successively, in the flow direction of the coolant fluid, an evaporator 14 located in the duct 4 and adapted to exchange heat with the extracted air, a compressor 15, a condenser 16 adapted to exchange heat with the fluid contained in the tank 3, and an expander 17. The flow direction of the coolant fluid is shown by arrows. In addition, the phase and the pressure of the coolant fluid are identified by references VBD (Low Steam Pressure), VHP (High Steam Pressure), LHP (High Liquid Pressure), and LBP (Low Liquid Pressure).
More particularly, the condenser 16 has the shape of a coil and is located within the tank 3 of the water heater, in order to exchange directly heat with the fluid contained in the tank 3.
The facility also includes a heat exchanger of the double flow type 18, within which the injected airflow F1 in the dwelling 2 exchanges heat with the extracted airflow F2 of the dwelling 2.
More specifically, the double flow exchanger 18 allows exchanging heat between the inlet air flow F1 from the air injection network 11 and directed towards the dwelling 2 through an individual distribution duct 19 allowing to distribute the injected air into the various living rooms 12, and the outgoing airflow F2 from the technical rooms 5, conveyed from these various rooms by the air extraction duct 4, and directed towards the air extraction network 8.
Hence, the heat exchanger of the double flow type 18 is located upstream of the evaporator 14 of the thermodynamic circuit 13, in the direction of flow of the extracted air.
In addition, the facility comprises recycling means 20 allowing to direct part of the injected air, from the air injection network 11, directly into the air extraction network 8, that is to say without rejecting it into the dwelling 2. The recycling means are located upstream of the evaporator, in the direction of flow of the extracted air, and comprise a controlled valve and a bypass branch allowing to divert the injected air out of the double flow exchanger 18.
In a second embodiment shown in FIG. 4, the condenser 16 is located outside the tank 3. The heat exchange means 10 therefore comprise in addition a secondary circuit 21 of heat exchange, equipped with a pump 22 and within which flows a coolant fluid. The secondary circuit 21 passes through the condenser 16 in order to exchange heat with the coolant fluid. The secondary circuit 21 includes in addition a heat exchanger 23 being in the shape of a coil, located inside the tank 3 of the water heater, in order to exchange heat with the fluid contained in the tank 3.
The structure of the heat exchange means 10 is described above in combination with a ventilation of the double flow type. However, the structure of the heat exchange means 10 remains unaltered in the case of a simple flow ventilation, only the air injection network 11 and the heat exchanger of the double flow type 18 being in this case non existent.
It is hence evident that the facility according to the invention allows recovering, at least in part, the thermal energy available in the extracted air in order to convey it to the fluid contained in the tank for producing sanitary hot water with a high performance.
In addition, such a facility may be adapted to congregate housing, because of the use of an air extraction network common to the various dwellings to which is connected each corresponding air extraction duct.
Moreover, in the particular case of the double flow ventilation, use of an exchanger of the double flow type allows reducing thermal losses through the extracted air.
It is understood that the invention is not limited to the embodiments of this facility, described above by way of not limiting examples, but, on the contrary, it embraces all the variations.
The invention relates to a facility for producing sanitary hot water for congregate housing.
Given the environmental constraints and the high cost of energy, it is necessary to reduce the consumption of different facilities in housings. The needs of the facility for heating housings have been significantly reduced, in particular by the use of new insulation materials, the placing of adapted glazing and the reduction of thermal bridges during the construction of the building.
Similarly, the needs of a facility intended for the ventilation of the housing are significantly reduced by using a double flow ventilation, allowing to recover calories on the extracted airflow in order to transfer them to the injected airflow or by using a modulated ventilation, the operation of which is limited to actual and functional needs, for example, on the hygrometry rate inside the housing.
Presently, it is observed that, in the “low consumption” type homes, the facility intended for producing sanitary hot water is that which uses most of the energy.
It is therefore evident that it is necessary to reduce the energy needs of this type of facility.
For this purpose, it is known to use a facility for producing sanitary hot water comprising a water heater with a tank within which is stored fluid to be heated, and a controlled mechanical ventilation system intended to extract air from a housing, the controlled mechanical ventilation system being coupled to a thermodynamic circuit within which flows a coolant fluid, the thermodynamic circuit comprising an evaporator adapted for exchanging heat with the extracted air, a compressor, an expander and a condenser adapted for exchanging heat with the fluid contained in the tank.
Such a facility is generally designated by the term “thermodynamic water heater on the extracted air”.
Such a type of facility allows recovering part of the heat of the extracted air and transferring it to the fluid contained in the tank of the water heater, through the thermodynamic circuit and heat exchangers formed by the evaporator and the condenser.
However, the known facilities of this type are not suited for congregate housing.
For safety reasons related to the spread of fires, it is not possible to divert the extracted air from each facility in an extraction duct common to the various dwellings. Where such a facility was provided and in the assumption of a failure at the extraction point of one of the dwellings, for example in case of failure of a corresponding extraction fan, the phenomena of overpressure within the common duct could lead to a spread risk of smoke or fire inside the dwelling equipped with the failing fan.
It would then be necessary that each dwelling have its own air extraction network, which generates additional costs and/or a major difficulty of implementation.
There are other facilities for producing sanitary hot water, suitable for congregate housing.
For example, it is known using a centralised facility for producing hot water, equipped with a boiler connected to a distribution network capable of conveying sanitary hot water to the various dwellings. Such a facility must hence comprise at least a pump to flow the hot water
This type of facility is costly and it results in heavy thermal losses, since the hot water must flow over long distances in the distribution network, and in electric power consumption at the pumps too.
Another known facility is the congregate solar water heater. Such a facility comprises a common tank of water to be heated, from which extends a distribution network of sanitary hot water to the various dwellings. This type of facility has the same drawbacks as the previous facility.
The purpose of the invention is to remedy these drawbacks by providing a facility for producing sanitary hot water suitable for congregate housing, inexpensive, and with an increased performance.
To this end, the invention relates to a facility for producing sanitary hot water for a congregate housing, characterised in that it comprises a plurality of water heaters, intended to equip a plurality of individual dwellings of the housing, each water heater comprising a tank within which is stored fluid to be heated, each dwelling being furthermore equipped with at least an air extraction duct, particularly in the technical rooms, connected to an air extraction network common to the various dwellings, each dwelling furthermore comprising heat exchange means adapted to exchange heat between the extracted air flowing through the air extraction duct and the fluid contained in the tank, so as to heat the fluid in order to produce sanitary hot water.
The sanitary hot water may be produced in each dwelling so as to limit the thermal loses due to the flowing of water over long distances.
In addition, the calories drawn from the extracted air allow heating of the fluid contained in the tank of the water heater, in order to increase the overall performance of the facility.
Finally, the fact that the extraction is carried out through an air extraction common network avoids the necessity to provide for ventilation means, such as fans, in each dwelling. In this way, the aforementioned overpressure phenomena within the extraction network are avoided and, consequently, the risks of fire spreading also.
According to a characteristic of the invention, the heat exchange means comprise a thermodynamic circuit, within which flows a coolant fluid, the thermodynamic circuit comprising an evaporator adapted to exchange heat with the extracted air, a compressor, an expander, and a condenser adapted to exchange heat with the fluid contained in the tank.
According to an embodiment of the invention, the condenser is located within the tank of the heater water, in order to exchange directly heat with the fluid contained in the tank.
According to another embodiment of the invention, the heat exchange means comprise a secondary circuit of heat exchange within which flows a coolant fluid, passing through the condenser so as to exchange heat with the coolant fluid, the secondary circuit furthermore comprising a heat exchanger located within the tank of the water heater, so as to exchange heat with the fluid contained in the tank.
According to a possibility of the invention, the facility comprises an air injection network common to the various dwellings, each dwelling being equipped with a heat exchanger of the double flow type, wherein the airflow injected into the dwelling and being drawn from the air injection network exchanges heat with the airflow extracted from the dwelling.
Using a double flow type heat exchanger allows reducing the thermal losses associated with the air extraction and recover part of the calories contained in the extracted air to heat the injected air in the dwelling.
Preferably, the heat exchanger of the double flow type is located upstream of the heat exchange means between the extracted air and the fluid contained in the tank, in the flow direction of the extracted air.
According to a characteristic of the invention, the facility comprises recycling means allowing directing part of the injected air from the air injection network, directly into the air extraction network, upstream of the heat exchange means in the flow direction of the extracted air.
The recycling means allow accelerating, should it be necessary, the airflow flowing through the heat exchange means, in order to promote heating of the sanitary hot water.
Preferably, the air extraction network, common to the various dwellings is equipped with at least one fan capable of carrying out the air extraction from each dwelling.
According to a possibility of the invention, the air injection network, common to the various dwellings, is equipped with at least one fan capable of carrying out the air injection from each dwelling.
In any case, the invention will be better understood by using the following description, with reference to the attached schematic drawing showing, by way of not limiting examples, several embodiments of this facility for producing sanitary hot water.
FIG. 1 is a schematic illustration of a congregate housing equipped with a facility according to the invention;
FIG. 2 is a plan of a dwelling of the housing detailing the location of the various elements of the facility;
FIG. 3 is a schematic view of part of the facility, according to a first embodiment of the invention;
FIG. 4 is a view corresponding to FIG. 3, of a second embodiment of the invention.
A congregate housing 1 equipped with a facility for producing sanitary hot water is shown in FIG. 1.
The housing comprises a plurality of dwellings 2 distributed over several floors. Only one dwelling 2 per floor is shown in FIG. 1 for readability reasons.
Each dwelling 2 comprises a water heater comprising a tank 3 within which is stored a fluid to be heated.
Each dwelling 2 is furthermore equipped with at least an air extraction duct 4, in particular in the technical rooms 5, as better shown in FIG. 2.
In the case shown in FIGS. 1 and 2, the intake of air for a dwelling 2 is through the windows 6 and is extracted through extraction air vents 7 communicating with the duct 4, as shown by arrows. Therefore, the facility operates with a ventilation system of the single flow type.
The injected airflows and the extracted air shown in FIG. 2 are only given by way of not limiting example. It is understood that different embodiments may be considered.
The air extraction duct 4 of each dwelling 2 is connected to an air extraction network 8 common to the various dwellings, the air extraction network 8 comprising an upper part equipped with a fan 9.
In addition, each dwelling 2 comprises heat exchange means 10 adapted to heat the fluid contained in the tank 3 from the extracted air flowing through the duct 4.
According to another possibility of the invention, an air injection network 11 common to the various dwellings (FIGS. 3 and 4), is equipped with a fan. In this case, the injection and the extraction of air are controlled simultaneously. This is what is known as double flow type ventilation. In the case of double flow ventilation, air intakes are carried out, not any longer through the windows, but at the air inlet mouths located in the living rooms 12.
The structure of the heat exchange means 10 will now be described in more detail with reference to FIGS. 3 and 4, in the case of double flow type ventilation.
According to a first embodiment shown in FIG. 3, the heat exchange means 10 comprise a thermodynamic circuit 13 within which flows a coolant fluid.
The thermodynamic circuit 13 comprises successively, in the flow direction of the coolant fluid, an evaporator 14 located in the duct 4 and adapted to exchange heat with the extracted air, a compressor 15, a condenser 16 adapted to exchange heat with the fluid contained in the tank 3, and an expander 17. The flow direction of the coolant fluid is shown by arrows. In addition, the phase and the pressure of the coolant fluid are identified by references VBD (Low Steam Pressure), VHP (High Steam Pressure), LHP (High Liquid Pressure), and LBP (Low Liquid Pressure).
More particularly, the condenser 16 has the shape of a coil and is located within the tank 3 of the water heater, in order to exchange directly heat with the fluid contained in the tank 3.
The facility also includes a heat exchanger of the double flow type 18, within which the injected airflow F1 in the dwelling 2 exchanges heat with the extracted airflow F2 of the dwelling 2.
More specifically, the double flow exchanger 18 allows exchanging heat between the inlet air flow F1 from the air injection network 11 and directed towards the dwelling 2 through an individual distribution duct 19 allowing to distribute the injected air into the various living rooms 12, and the outgoing airflow F2 from the technical rooms 5, conveyed from these various rooms by the air extraction duct 4, and directed towards the air extraction network 8.
Hence, the heat exchanger of the double flow type 18 is located upstream of the evaporator 14 of the thermodynamic circuit 13, in the direction of flow of the extracted air.
In addition, the facility comprises recycling means 20 allowing to direct part of the injected air, from the air injection network 11, directly into the air extraction network 8, that is to say without rejecting it into the dwelling 2. The recycling means are located upstream of the evaporator, in the direction of flow of the extracted air, and comprise a controlled valve and a bypass branch allowing to divert the injected air out of the double flow exchanger 18.
In a second embodiment shown in FIG. 4, the condenser 16 is located outside the tank 3. The heat exchange means 10 therefore comprise in addition a secondary circuit 21 of heat exchange, equipped with a pump 22 and within which flows a coolant fluid. The secondary circuit 21 passes through the condenser 16 in order to exchange heat with the coolant fluid. The secondary circuit 21 includes in addition a heat exchanger 23 being in the shape of a coil, located inside the tank 3 of the water heater, in order to exchange heat with the fluid contained in the tank 3.
The structure of the heat exchange means 10 is described above in combination with a ventilation of the double flow type. However, the structure of the heat exchange means 10 remains unaltered in the case of a simple flow ventilation, only the air injection network 11 and the heat exchanger of the double flow type 18 being in this case non existent.
It is hence evident that the facility according to the invention allows recovering, at least in part, the thermal energy available in the extracted air in order to convey it to the fluid contained in the tank for producing sanitary hot water with a high performance.
In addition, such a facility may be adapted to congregate housing, because of the use of an air extraction network common to the various dwellings to which is connected each corresponding air extraction duct.
Moreover, in the particular case of the double flow ventilation, use of an exchanger of the double flow type allows reducing thermal losses through the extracted air.
It is understood that the invention is not limited to the embodiments of this facility, described above by way of not limiting examples, but, on the contrary, it embraces all the variations.

Claims

1. Facility for producing sanitary hot water for congregate housing characterized in that a plurality of water heaters, intended to equip a plurality of individual dwellings of the housing, each water heater comprising a tank within which is stored a fluid to be heated, each dwelling being further equipped with at least one air extraction duct connected to an air extraction network common to the various dwellings, each dwelling further comprising heat exchanging means adapted to exchange heat between the extracted air flowing through the air extraction duct and the fluid contained in the tank, so as to heat the fluid in order to produce sanitary hot water, the air extraction network common to the various dwellings being equipped with at least one fan capable of creating a negative air pressure in the said extraction network, so as to carry out the air extraction from every dwelling.

2. Facility according to claim 1, the heat exchange means comprise a thermodynamic circuit within which flows a coolant fluid, the thermodynamic circuit comprising an evaporator adapted to exchange heat with the extracted air, a compressor, an expander, and a condenser adapted to exchange heat with the fluid contained in the tank.

3. Facility according to claim 2, the condenser is located inside the tank of the water heater, in order to exchange directly heat with the fluid contained in the tank.

4. Facility according to claim 1, the heat exchange means comprise a secondary circuit of heat exchange within which flows a coolant fluid, passing through the condenser so as to exchange heat with the coolant fluid, the secondary circuit further comprising a heat exchanger located inside the tank of the water heater, so as to exchange heat with the fluid contained in the tank.

5. Facility according to an air injection network common to the various dwellings, each dwelling being equipped with a heat exchanger of the double flow type, wherein injected airflow in the dwelling and coming from the air injection network exchanges heat with the airflow extracted from the dwelling.

6. Facility according to claim 5, the heat exchanger of the double flow type is located upstream of the heat exchange means between the extracted air and the fluid contained in the tank, in the flow direction of the extracted air.

7. Facility according to recycling means allowing to direct part of the injected air from the air injection network, directly into the air extraction network, upstream of the heat exchange means in the flow direction of the extracted air.

8. Facility according to, the air injection network common to the various dwellings is equipped with at least one fan capable of carrying out the air injection of each dwelling.