FR3058784A1 - SYSTEM FOR REFRIGERATING A BUILDING - Google Patents

Abstract

Refreshment system for producing cooled water for refreshing the interior of a building (B), comprising a reservoir (8) to be disposed in a crawl space (2) of said building (B), said reservoir (8) having a large footprint on the ground and being intended to be in thermal contact with the ground (S), said reservoir (8) being intended to be partially filled with water and partially with air, means capable of maintaining the presence of a layer of air above the water, fans (30) ensuring the circulation of air between the inside and the outside of the tank so as to cause cooling of the water by evaporation and sensible heat exchange and connection means to a cooling floor (6) for cooling the building.

Description

Holder (s): ATOMIC AND ALTERNATIVE ENERGY COMMISSIONER Public establishment, UNIVERSITE SAVOIE MONT BLANC Public establishment.

Extension request (s)

Agent (s): BREVALEX Limited liability company.

164 / SYSTEM FOR COOLING A BUILDING.

FR 3 058 784 - A1

16 // Cooling system for producing cooled water for cooling the interior of a building (B), comprising a tank (8) intended to be placed in a crawl space (2) of said building (B) , said tank (8) having a large footprint on the ground and being intended to be in thermal contact with the ground (S), said tank (8) being intended to be partially filled with water and partially with air, suitable means maintaining the presence of an air layer above the water, fans (30) ensuring the circulation of air between the inside and the outside of the tank so as to cause the cooling of the water by evaporation and sensible heat exchange and means for connection to a cooling floor (6) in order to cool the building.

SYSTEM FOR COOLING A BUILDING

DESCRIPTION

TECHNICAL AREA AND PRIOR ART

The present invention relates to a system for cooling a building, in particular a residential or tertiary building.

In order to actively cool the interior of a building, there are several types of machines:

Compression refrigeration machines or heat pumps, they use a refrigeration cycle with compression most often performed using an electrical device. These are very effective but the compression stage consumes a lot of energy. In addition, a refrigerant gas is used in the refrigeration cycle which is liable to leak. Leaks further increase the carbon footprint of refrigeration machines.

Ab / ad sorption machines: the working principle of these machines consists in spraying water in fine droplets in a vacuum container. Due to the low pressure, the water evaporates. Liquid water circulates in a circuit passing through the container, this water is then cooled. A sorbent is placed in the container and recreates or maintains the vacuum. These machines have better yields than those of refrigeration machines but their implementation and maintenance are often very complex.

Adiabatic machines: these use the power taken from their environment by the evaporation of a fluid, most often water. We can distinguish between direct and indirect machines. Direct machines spray water droplets into an air flow, evaporation is caused and then cold moist air is sent directly to the room to be cooled. However, they are not very suitable for conventional sub-ventilation systems because these are generally fitted with single-flow ventilation systems extracting air from the interior of the building towards the exterior. These systems are therefore not suitable for sending cold humid air into the building. Furthermore, sending humid air directly into the building significantly increases the humidity level in the building. Indirect adiabatic machines use the same principle as direct adiabatic machines, but the air extracted from the house is humidified and cools the air entering the house via a double-flow ventilation exchanger. However, these machines show their limits in the event of heavy loads or external conditions which are not conducive to evaporation. For example, during a heat wave these systems find it difficult to reach acceptable temperature levels.

Desiccant wheels; these work on the same principle as adiabatic machines but also use a dehydrating element which allows to control the humidity of the air. The salts need to be regenerated by heating to keep their dehydrating power.

There are also systems circulating water on a roof of a building to evaporate and cool the water before storage in a buried tank. On the one hand, these systems have a relatively high cost of implementation. On the other hand, when the evaporation takes place outside, a significant part of the energy of this evaporation is not valued since it is dissipated in the ambient air.

STATEMENT OF THE INVENTION

It is therefore an object of the present invention to provide a building cooling system having good efficiency while being relatively simple to produce and at reduced cost compared to existing systems.

The aim stated above is achieved by a system intended to be placed in a crawlspace of a building, comprising a tank having a large footprint, the bottom bottom of the tank being intended to be in thermal contact with the ground. The reservoir is intended to be partly filled with water and means ensuring cooling at least by evaporation of the water in the reservoir by means of air circulation from the external environment.

For example, the system comprises means for ensuring forced convection of the air between the interior of the tank and the crawlspace or the exterior of the building via one or more ducts.

Advantageously, the tank comprises means for maintaining an air layer above the volume of water at a substantially constant thickness and means for circulating the air between the inside and the outside of the tank through the tank so as to cause cooling of the water by evaporation. In addition, it is intended to be connected to a hydraulic circuit allowing the fresh water from the tank to be used by cooling the building via a heat exchanger.

Thanks to the invention, the water is cooled on the one hand thanks to its contact with the ground, on the other hand by an evaporation phenomenon and finally by heat exchange between the water and the humid fresh air, in indeed the air at the start of its journey in the tank cools by evaporation and becomes humid, then this air also cools the liquid water in the tank significantly. Thus all the cooling potential allowed by evaporation is recovered. Cooling efficiency is maximized.

The water thus cooled can then circulate in a transmitter installed in the building to cool it, it can be the circuit intended for heating / cooling such as that of the heated floor or fan coils.

The means for circulating the air through the tank comprise for example one or more fans arranged in the tank or outside of it.

The means for maintaining an air layer include, for example, elements capable of floating on water and the reservoir comprises a flexible upper wall, the layer or air layer is then defined by the thickness of the floating elements. The thickness of the air layer remains substantially constant even if the volume of water varies for example due to evaporation.

Preferably the humid air extracted from the tank is discharged outside the crawl space to avoid an increase in the humidity level therein. The air injected into the tank is preferably taken from the crawl space because it is generally cooler than that outside the building.

The present invention therefore relates to a cooling system intended to produce cooled water for the cooling of the interior of a building, comprising a tank intended to be placed in a crawlspace of said building, said tank comprising a large footprint. on the ground and being intended to be in thermal contact with the ground, said tank being intended to be partially filled with water, means capable of maintaining the presence of a layer of air above the water, means ensuring the air circulation between the inside and the outside of the tank so as to cause the water to cool by evaporation and sensible heat exchange and means for connection to a water circulation circuit in the building in view to refresh it.

Preferably, the means capable of maintaining the presence of an air layer above the water are capable of maintaining an air layer of substantially constant thickness throughout the tank.

For example, in the case where the reservoir has at least one flexible upper part, the means capable of maintaining the presence of an air layer above the water may comprise at least one element capable of floating on the water and interposed in water and in permanent contact with at least part of the flexible upper part.

For example, the means capable of maintaining the presence of an air layer above the water may comprise several elements capable of floating arranged relative to one another so as to delimit air circulation channels between them.

The means ensuring the circulation of air between the inside and the outside of the tank are for example such that they take air from the crawl space or outside the building and / or such as air leaving the tank is discharged outside the crawlspace.

For example, the means ensuring the circulation of air between the interior and the exterior of the tank comprise at least one fan generating an air circulation on the surface of the water. In an exemplary embodiment, the fan can be arranged in the tank. Advantageously, the system can include at least one fan per channel defined by the elements capable of floating.

In another exemplary embodiment, the fan is arranged outside the tank.

The system can advantageously include a heat exchanger between the air leaving the tank and the water entering the tank after having circulated in the building.

For example, the means of connection to a circuit for circulating water in the building with a view to cooling it comprise at least one water return orifice and at least one water withdrawal orifice situated in a wall of the tank, said orifices being advantageously arranged so as to promote brazing of the water.

The present invention also relates to a building comprising a floor, a cooling area located above the floor and a crawl space located between the floor and the floor, a system according to the invention arranged in the crawl space, the tank resting on the ground, at least one transmitter intended to cool the area to be refreshed to which the connection means are connected to a circuit for circulating water in the building in order to cool it.

The transmitter comprises for example at least one hydraulic circuit in the floor and / or at least one fan coil.

The building can advantageously include means for controlling the system comprising means for measuring the temperature of the water in the tank and controlling the means ensuring the circulation of air between the inside and the outside of the tank, when the water temperature is lower than a set temperature and / or means for measuring the temperature of the soil at the level of the reservoir and controlling it when the temperature of the soil is greater than a given temperature. The control means comprise for example a predictive control command connected to a weather forecast system.

The present invention also relates to a process for cooling the water contained in the tank of the system according to the invention, comprising a step of cooling the water by heat exchange with the soil, a step of measuring the temperature of the water in the tank, if the temperature is above a set temperature, a step of cooling the water by evaporation and by substantial exchange between the air saturated in humidity and the water by actuating the means ensuring air circulation between the inside and outside of the tank.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be better understood on the basis of the description which follows and of the appended drawings in which:

FIG. 1 is a perspective view of an example of a cooling system according to the invention arranged in the crawl space of a building,

FIG. 2 is another perspective view of the system of FIG. 1 arranged in the building,

FIG. 3 is a schematic side view of a part of the system of FIG. 1 and of the fluid connections thereof,

FIG. 4 is a schematic side view of part of another example of a cooling system according to the invention,

FIG. 5 is a schematic top view of an exemplary embodiment of the cooling system according to the invention,

- Figure 6 is a schematic top view of another example of a cooling system according to the invention

DETAILED PRESENTATION OF PARTICULAR EMBODIMENTS

In Figures 1 and 2, we can see an example of a cooling system SR installed in a building B built on soil S.

The building is for example a residential dwelling comprising a crawl space 2 located between the floor S and the floor 4 of the building B. The area to be refreshed of the building is located above the floor. In the example shown, the building B has a circuit 6 allowing the circulation of water in the floor 4. This circuit 6 is advantageously used for the circulation of a hot or cold fluid for heating or cooling the interior. of the building. This type of circuit is then generally called "heating / cooling floor".

The system comprises a reservoir 8 having a large footprint, for example between 3 m ² and 20 m ² . This footprint allows on the one hand to ensure a significant heat exchange between the soil and the tank, on the other hand to offer a large surface area for the evaporation of water. Furthermore, it has a low height compatible with the height of the crawl space and, due to the large footprint, the water height is reduced to about ten centimeters.

In addition, this shape is particularly suitable for installation in a crawl space.

In the example shown, the reservoir 8 has the shape of a rectangular parallelepiped which is generally adapted to the shape of a crawl space, but any other arrangement can be envisaged, for example a circular or even arbitrary shape.

The reservoir 8 has a lower bottom 10. The latter rests on the ground S and is in thermal contact with the ground so as to exchange heat with the latter. Indeed, the ground constitutes an important cold source, for example in summer at 5 m depth the temperature is substantially constant and around 12 ° C.

The reservoir also has a side wall 12 and an upper bottom 14.

The reservoir is intended to be partially filled with water 16 and an air space or an air layer 18 is present between the upper surface 16.1 of the water and the upper bottom 4.

In the present application, the water may contain one or more additives such as glycol, an anti-mud, an anti-algae, etc.

Advantageously, the reservoir 8 is made of flexible material, for example polyester fabric with PVC coating. Alternatively, one could provide that only an upper part of the side wall is flexible. In addition, the use of a flexible tank makes it easier to install in crawl spaces, which generally have reduced access.

The reservoir 8 advantageously comprises means capable of maintaining a substantially constant thickness of the air space 18, ensuring uniform and optimal operation of the system over time. The means capable of maintaining a substantially constant thickness of the air space 18 comprise elements capable of floating on the water 16 and interposed between the surface 16.1 of the water and the upper bottom 12. For example, it is a question of 'inflatable elements 22 fixed to the upper bottom. As a variant, the elements 22 could be made of a solid material, such as polystyrene, another expanded material which may be in contact with water or even swellable. Thus the upper bottom 14 follows the water level and a substantially constant thickness of the air space 18 is obtained.

As will be described later, the air is intended to circulate in the air space 18. The elements 22 then have a shape and an arrangement which does not hinder this circulation or even promote this circulation. In the example shown, the elements 22 extend longitudinally between two opposite parts 12.1, 12.2 of the side wall 12 through which the air supplies and discharges are made. The elements then define between them air circulation channels. One can consider curved elements defining curved channels. One can also consider using elements 22 which do not define channels.

The system also includes means for supplying water 23 to the reservoir 8, for example a connection to the city water circuit or to a rainwater recovery system. The tank also includes a drain 25. It should be noted that these supply means 23 are used during the installation of the system and to supplement the water level (FIG. 3).

The system also comprises means for introducing air into the tank, circulating it in the tank 8 at the level of the air space 18 and extracting it from the tank 8. The means for introducing air comprise at least one air intake inlet 26, preferably several air intake entrances opening into the air space 18 and at least one air exhaust outlet 28, preferably several exhaust outlets coming from of the air gap. In addition, the means for introducing air comprise at least one fan 30 ensuring the circulation of air from the outside to the inside of the tank and then to the outside of the tank. Preferably filtration means are provided at the air intake, for example a grid to prevent, for example, that insects are sucked.

In FIGS. 1, 2 and 5, the system comprises several fans 30 located in the tank, each arranged in a channel delimited by two elements 22. Several fans per channel could be envisaged depending on the width and / or the length of the channel. In this example, each channel is supplied with air individually, and each channel is exhausted individually. In this example, the fans are adapted to withstand a high humidity level.

In FIG. 6, all the channels are supplied in parallel by common supply means 32 comprising a main duct 34 provided with a fan 30 and as many secondary ducts 36 as there are supply inputs 26, connected by one end to the main duct 34 and by another end to a supply inlet 26. In this example, a single fan is then advantageously used. The system also includes common exhaust means 38 having a structure similar to the common supply means 34. Preferably, the means 34 and 38 are adapted to ensure a balanced air flow between the channels

It will be understood that the examples of FIGS. 5 and 6 could be combined, the reservoir possibly comprising common supply means and individual outlets and vice versa.

In addition, it is possible, as an alternative to the system of FIG. 5, to arrange the fans outside the tank.

Preferably, the air supplying the air space 18 is taken from the crawl space because it is generally colder than outside the building. One could however plan to take the air either in the crawl space or outside the building. In the case where the air is taken from the crawl space, means are advantageously provided, such as a valve, to prevent moisture from escaping into the crawl space when the fans are not operating. Regulation means could advantageously be provided at the level of the supply means to allow the most suitable source of air injected into the reservoir to be chosen.

Preferably also, the air leaving the tank is discharged outside the crawl space to avoid an excessive increase in the humidity level in the crawl space.

The system also comprises means 40 for connection of the reservoir 8, more particularly of the layer of water to one or more emitters, in the example shown in FIGS. 1 and 2, it is the heated floor. The means 40 ensure the circulation of water from the tank to the heating floor and its return to the tank, for example by means of a pump. The connection means 40 comprise at least one supply orifice 42 and at least one withdrawal orifice 44 in the tank. Preferably, the feed orifice 42 and the withdrawal orifice 44 are arranged so as to obtain mixing of the water in the whole of the tank in order to homogenize the temperature of the water, making it possible to maximize exchanges and avoid l appearance of dead zones and short circuits. For example the openings 42 and 44 are arranged at opposite corners of the tank as shown in the figure

5.

Alternatively or in addition, the transmitter could include one or more fan coil units or any other air / water exchanger.

Advantageously, the system includes means for measuring the water temperature in order to control the cooling of the water as a function of a set temperature. The set temperature depends for example on the power to be supplied by the system.

The operation of the system will now be described.

The reservoir is partially filled with water, the thickness of the air space is fixed by the floating elements 22.

The water exchanges heat with the soil S through the lower bottom 10, the water is therefore cooled. This cooling mode is preferred because it does not consume electrical energy to operate the fans.

The water temperature is measured, if it is above the setpoint, the fan or fans are activated. Preferably, it is sought to maintain a water temperature below 19 ° C.

Fresh and dry air preferably taken from the crawl space is admitted into the tank and circulates above the surface 16.1 of water 16. On a first part I of the path of the air in the air space , an evaporation phenomenon appears which has the effect of lowering the water temperature and increasing the humidity of the air. Then, during a second part II of the journey, when the air reaches saturation, a significant exchange takes place between the water and the cold humid air without change of phase.

The length of the air circulation path in the tank is therefore advantageously determined so that both the evaporation and the sensitive exchange take place, which makes it possible to recover all the cooling potential.

The water thus cooled circulates in the emitter (s), which has the effect of cooling the building.

Preferably the air circulation in the tank takes place at night or in the morning so as to be able to use the coldest air available. And the circulation of chilled water generally takes place during the day. This circulation of water is preferably subject to a temperature measurement in the building.

Advantageously, the system can include a predictive control command connected to a weather forecast system to control the cooling of the water as a function of weather conditions. For example, in the event of a drop in temperatures, the system is preferably activated to provide storage of cold water for use when a rise in temperatures is expected.

Preferably, means for measuring the temperature of the soil at the level of the reservoir are provided so as to detect an undesired increase in the temperature of the soil and in this case to actuate the fans to cool the water in the reservoir.

As shown in FIG. 4, the system can advantageously include a heat exchanger 46 between the cold humid air leaving the tank 8 and the water 48 entering the tank 8 coming from the transmitter and which has been heated while circulating. for example in the heated floor. This exchanger 46 makes it possible to still recover part of the potential of the cold humid air.

It will be understood that a system with several reservoirs does not depart from the scope of the present invention.

For example, the reservoir has a footprint of 30 m ² , a water height of 5 cm to 15 cm, ie a water volume of approximately 3000 liters. The air space has for example a thickness of 5 cm to 10 cm. The tank can have a thickness of about 30 cm.

Evaporation consumes water. Advantageously, means for detecting the water level can be provided, for example a detection gauge, for making additional water, for example automatically via a connection of the reservoir to the water of the water network. urban or to a rainwater recovery tank.

The level detection means can be used to detect a malfunction.

A purge system connected to the evacuation of water from the house could advantageously be provided so as to empty the tank when the system is not working.

Experimental measurements have shown that with ambient air at 20 ° C, 40% relative humidity, and a weak wind at lm / s blowing on a surface of water, we obtain an evaporation power of 150 W / m ² . This power depends on the temperature, humidity and air speed conditions.

Concerning the exchanges with the soil, measurements made it possible to evaluate the exchanges between water stored in a plastic tank placed on a soil and the soil itself. The exchanges were evaluated at around 10 W / K / m ² with a soil temperature taken 30 cm deep below the ground. This means that if we have a stock of water at 20 ° C with 30 m ² of floor space, placed on a soil whose temperature at 30 cm is 17 ° C, the cold power is then 900 W. This power may be sufficient to dissipate the energy extracted from the building. If it is not sufficient, the fans can increase the cooling power by 4500 W.

Preferably, the water is cooled by exchange with the ground and the energy extracted from the building is balanced over several days with the energy dissipated by the soil and evaporation in order to maintain a water temperature that is substantially constant.

The cooling system according to the invention also has the advantage of having a particularly easy and aesthetic integration since there are no visible parts. In addition, it uses an unoccupied location. In addition, its operation is completely silent and the energy consumption of the fans is greatly reduced compared to that of a compressor.

The system allows the combination of evaporative cooling and geothermal cooling. It also makes it possible both to produce cold and to store cold, and very advantageously, to be able to separate over time the production of cold and its use and thus to be able to produce cold when the air is coolest. , in the morning and at night and to refresh the building in general in the afternoon.

This system is particularly suitable for integration into an individual dwelling. It can equip, for example, an RT2012 type house.

Claims (16)

1. A cooling system intended to produce water cooled for the cooling of the interior of a building (B), comprising a tank (8) intended to be placed in a crawl space (2) of said building (B), said tank (8) comprising a large footprint on the ground and being intended to be in thermal contact with the ground (S), said tank (8) being intended to be partially filled with water, means capable of maintaining the presence of an air layer (18) above the water (16), means ensuring the circulation of air between the inside and the outside of the tank (8) so as to cause the cooling of the water by evaporation and sensible heat exchange and means for connection to a water circulation circuit in the building in order to cool it. 2. System according to claim 1, in which the means capable of maintaining the presence of an air layer (18) above the water (16) are capable of maintaining an air layer of substantially thickness constant throughout the tank. 3. System according to claim 2, in which the reservoir (8) comprises at least one flexible upper part and the means capable of maintaining the presence of an air layer above the water comprise at least one element ( 22) able to float on water and interposed in water (8) and in permanent contact with at least part of the flexible upper part. 4. System according to claim 3, in which the means capable of maintaining the presence of an air layer above the water comprise several elements (22) capable of floating arranged relative to one another so as to delimit air circulation channels between them. 5. System according to one of claims 1 to 4, wherein the means ensuring the circulation of air between the inside and the outside of the tank are such that they take air from the crawl space or at the outside of the building and / or such that the air leaving the tank is discharged outside the crawl space. 6. System according to one of claims 1 to 5, wherein the means ensuring the circulation of air between the interior and the exterior of the tank comprise at least one fan (30) generating an air circulation at the water surface (16). 7. The system of claim 6, wherein the fan (30) is disposed in the tank (8). 8. System according to claim 7 in combination with claim 4, comprising at least one fan (30) per channel. 9. The system of claim 6, wherein the fan (30) is disposed outside the tank. 10. System according to one of claims 1 to 9, comprising a heat exchanger (46) between the air leaving the tank (8) and the water entering the tank after having circulated in the building (B). 11. System according to one of claims 1 to 10, in which the means for connection to a water circulation circuit in the building with a view to cooling it comprise at least one water return orifice and at least a water withdrawal orifice located in a wall of the tank, said orifices being arranged so as to promote brazing of the water. 12. Building comprising a floor (4), a cooling area located above the floor (4) and a crawl space (2) located between the floor (S) and the floor (4), a system according to one of claims 1 to 11 disposed in the crawl space (2), the tank (8) resting on the ground (S), at least one emitter (6) intended to cool the area to be cooled to which the means of connection to a water circulation circuit in the building in order to refresh it. 13. Building according to claim 12, wherein the transmitter comprises at least one hydraulic circuit in the floor and / or at least one fan coil. 14. Building according to claim 12 or 13, comprising means for controlling the system comprising means for measuring the temperature of the water in the tank and controlling the means ensuring the circulation of air between the interior and the outside the tank, when the water temperature is below a set temperature and / or means for measuring the temperature of the soil at the level of the tank and controlling the latter when the soil temperature is above a given temperature . 15. Building according to claim 14, wherein the control means comprise a predictive control command connected to a weather forecast system. 16. A method of cooling the water contained in the tank of the system according to one of claims 1 to 11, comprising - a step of cooling the water by heat exchange with the ground, - a step of measuring the temperature of the water in the tank, - If the temperature is above a set temperature, a step of cooling the water by evaporation and by appreciable exchange between the air saturated in humidity and the water by actuating the means ensuring the circulation of the air between the inside and outside of the tank. S.60732 1/2