Field of the invention

The present invention relates to an outer wall for a building, wherein the outer wall has at least one pipe adapted to transport gas for heating or cooling the outer wall. The invention also relates to a building comprising an outer wall according to the invention.

Background of the invention

A conventional outer wall has a frame that comprises a row of vertical wall studs arranged between an outer and an inner wall element. The frame constitutes a supporting part of the wall. The outer and inner wall elements are connected on each side of the vertical wall studs. Insulation material is arranged between the wall studs. The outer wall element often comprises a wind protection and an outer siding, which can be made of different materials, e.g. wood, bricks, sheet, stone or grout. The inner wall element comprises an inner siding, e.g. plastic or wood sheets. A disadvantage with such an outer wall is that the vertical wall studs constitute thermal bridges that conduct heat and cold between the outer and inner wall elements.

It is known to use double stud walls in order to reduce the sound transmission between rooms and apartments in a building. Double stud walls comprise two rows of vertical wall studs where the first row forms a first frame part and the second row forms a second frame part. The first and the second rows of the frame parts are arranged at a distance from each other so that a space is formed between the frame parts. Sound absorbing materials are arranged in the space between the frame parts.

A common way of heating a building is to use underfloor heating that comprises heating coils containing a heating transfer medium arranged in the floor in a building. An advantage with underfloor heating is that radiators on the wall are no longer needed. The most common underfloor heating is electrical underfloor heating. Another type of underfloor heating is waterborne underfloor heating, where the heat transfer medium is water. A problem with heating coils in the floor is that it could be a slow process to heat the room since the heating coils often are cast into concrete which leads to a slow transmission of heat to the room that is to be heated. A problem with underfloor heating having water as the heat transferring medium is that there is a risk of damage due to leakage of the water. Another problem with floor heating is that damage on the floor heating system often is difficult to repair.

WO2009006343 shows a structural wall panel with heating coils cast into a first inner concrete layer. The heating coils contain a heat conducting liquid and are adapted to transfer heat into the first concrete layer. A thermal insulating layer is arranged between the first concrete layer and a second outer concrete layer and is adapted to prevent the heat from the heat coils to be transferred to the second concrete layer. The greatest portion of the heat is then transferred through the first concrete layer to the area that is to be heated. A problem with this technique is the time it takes for the heat to be transferred through the concrete to the area which is to be heated.

DE102010045354 discloses a facade having a pipe system including flexible plastic pipes filled with medium having a capacity to be heated, e.g. water, air and hot liquid. The pipes are arranged on the outer side of the outer wall, and between an outer side of an outer wall and an insulation layer. The medium is heated by an air-heat pump, thermal solar collectors, or photovoltaic and/or thermal solar systems.

Object and summary of the invention It is an object of the present invention to at least partly overcome the above problems.

According to one aspect of the invention, this object is achieved by an outer wall for a building as defined in claim 1.

The outer wall comprises a frame, an outer wall element connected to one side of the frame and defining an outer side of the wall, an inner wall element connected to an opposite side of the frame and defining an inner side of the wall, and at least one pipe adapted to transport gas for heating or cooling the outer wall. The frame comprises an inner frame part connected to the inner wall element and including a plurality of vertical inner studs arranged at a distance from each other, and an outer frame part connected to the outer wall element and including a plurality of vertical outer studs arranged at a distance from each other and at a distance from the inner studs so that a cavity is formed between the outer and the inner frame parts. The outer wall comprises an isolation layer arranged in said cavity, and said at least one pipe is disposed between the outer and inner wall elements, and closer to the inner wall element than to the outer wall element, and at least the main part of the isolation layer is arranged between the pipe and the outer wall element. An outer wall in a building has one side facing outwards towards the surroundings on the outside of the building, and one side facing inwards the interior of the building. The outer wall element is a part of the outer wall that is disposed between the frame and the surroundings, and the inner wall element is a part of the outer wall that is disposed between the frame and the interior of the building. The outer wall element is the part of the outer wall that is furthest from the area to be heated. The inner wall element is the part of the outer wall that is closest to the area that is to be heated. The inner wall element is separated from the outer wall element by means of the frame and a layer of insulation. The inner wall element can e.g. include one or more wall boards, such as plastic or plywood boards. The outer wall element can e.g. comprise wood panels, brick, metal plate, stone or grout. According to the invention, the outer wall is provided with one or more pipes for transportation of gas. Suitably, the gas is air. The outer walls face outwards, and are therefore cooled due to the air on the outside of the building when the outdoor temperature is low. A cold outer wall, causes cooling of the warm air closest to the outer wall on the inside of the building, and can therefore cause downdraught.

An advantage with arranging the pipe between the outer and inner wall elements, and closer to the inner wall element than to the outer wall element, is that the pipe prevents cold from penetrating the building via the inner wall element, and therefore prevents downdraught. Further, the fact that the pipe is arranged closer to the inner wall element than the outer wall element, enables the main portion of the insulation to be arranged between the pipe and the outer wall element. Due to the fact that the main part of the isolation layer is arranged between the pipe and the outer wall element, it is ensured that most of the heat is transferred from the pipe to the interior of the building. Preferably, the pipe is arranged between the isolation layer and the inner wall element. Thus, there is no insulation between the pipe and the inner wall element, and it is ensured that the heat from the pipe is transferred to the inner wall element, and then transferred to the interior of the building. Even more preferably, the pipe is arranged in direct physical contact with the inner wall element to further facilitate transfer of heat from the pipe to the inner wall element.

According to the invention, the frame comprises an outer frame part connected to the outer wall element and an inner frame part connected to the inner wall element, wherein the outer and inner frame parts are arranged at a distance from each other so that a cavity is formed between the outer and the inner frame parts in which the isolation layer is arranged.

Due to the fact that the isolation layer is arranged in a cavity formed between the outer and inner frame parts, the isolation layer can be made continuous through the interior of the outer wall, and by that no thermal bridges occur between the inner and outer wall elements, which otherwise would transfer the heat from the pipe towards the outside of the building. Also the thickness of the isolation layer between the pipe and the outer wall element can be increased, which results in that the heat transferred from the pipe to the interior of the building is increased.

According to the invention, the pipe is adapted for the transport of gas, such as air, in order to heat or cool the inner wall element, instead of heated water or electrically heated coil. An advantage with using air in the pipe, instead of using water or an electrical cable, is that no damage will occur if the pipe is hit with a nail or a screw. If a hole or a crack occurs in the pipe, leaking air will not affect the wall or the building, and the heating would probably still work satisfactorily. On the other hand, if a pipe containing waterborne heat would be damaged, the water from the pipe will pour out with the result that water damage may occur in the building, and also the whole heating system will become useless until the leakage in the pipe is fixed. A wall with airborne heat thus allows drilling and nailing in the wall unlike a wall with waterborne heat. A small leakage of heated air from the pipe does not significantly affect its heating function. The only thing that will happen is that a flow of warm air will occur from the part of the wall where the leakage is, with an increase in the heating of this part as a result. Another advantage with using air compared to using water in a pipe, is that there is no risk for freezing damage if the heat supply in any way disappears so that the temperature in the wall lowers below zero degree Celsius. A low temperature may cause the water in the waterborne pipe to freeze, with the result that the pipe can crack and cause water damage when the temperature in the wall increases.

An advantage with using a pipe for heated air in the wall instead of setting up heating channels in the wall is that it is easy and quick to mount the pipes.

According to an embodiment of the invention, the distance between the pipe and the inner wall element is less than 10 cm, and preferably less than 5 cm. Reduced distance between the pipe and the inner wall element allows more heat to be transferred to the inner wall element, which increases the effectiveness of the pipe. In order to achieve maximum transmission of heat between the pipe and the inner wall element at least a part of the pipe can be arranged in physical contact with the inner wall element. However, sometimes it can be advantageous to dispose the pipe at a short distance from the inner wall element to avoid screws and nails from the outside of the inner wall element to enter into the pipe, for example, when paintings are suspended on the inner wall element.

According to an embodiment of the invention, the pipe is arranged in loops along the inner wall element. Since the pipe is arranged along the inner wall element, and the isolation layer separates the outer wall element from the inner wall element, most of the heat from the pipe will be transferred to the inner wall element, which in turn transfers the heat to the area which is to be heated. The loops make it possible to cover a large area of the inner wall element with the pipe. The loops are preferably arranged in close vicinity of the inner wall element in order to increase the percentage of heat which is transferred to the inner wall element.

The inner frame part comprises a number of vertical inner studs arranged at a distance from each other, and the pipe is arranged between the inner studs. For example, the loops are arranged between the inner studs. Disposing the pipe between the inner studs makes it possible to reach as close as possible to the inner wall element. Preferably the pipe is in physical contact with the inner wall element. In this way it is also possible to arrange enough insulation material between the pipe and the outer wall element to provide sufficient insulation of the pipe from the outer wall element.

According to an embodiment of the invention, the outer wall part comprises a number of vertical outer studs arranged at a distance from each other and at a distance from the inner studs, wherein vertical outer and inner studs are arranged so that they form two rows and said cavity is formed between the rows.

According to an embodiment of the invention, the outer wall comprises a vapour barrier arranged between the pipe and the inner wall element, and the vapour barrier is made of aluminium foil. The vapour barrier prevents damp from penetrating the inner wall element. A problem with vapour barriers, e.g. made of plastic foil, is that condensation may occur on the inside of the vapour barrier which results in damp in the insulation. Due to the heat in the pipe in the wall, condensation is prevented to be formed on the inside of the vapour barrier and therefore prevents damp in the insulation. Advantageously the vapour barrier is made out of aluminium foil. Aluminium foil has a high thermal conductivity and contributes to heating transmission from the pipe to the inner wall element.

According to another aspect of the invention, the object of the invention is achieved by a building as defined in claim 9.

The building comprises an outer wall according the invention, and a heat exchanger adapted to transfer heat to air, wherein said pipe is connected to the heat exchanger so that heated air is transferred from the heat exchanger to the pipe. An advantage with heating the building with air that is heated by means of a heat exchanger is that it is cheap and makes it possible to recycle heat from the ventilation of the house. It also makes the device more environmentally friendly since less energy is needed to keep the building heated.

According to an embodiment of the invention, the pipe and the heat exchanger constitute a closed system for the circulation of air. This increases the effectiveness of the heat exchanger by means of preserving the remaining heat in the pipe.

According to an embodiment of the invention, the building comprises an air-heat pump containing said heat exchanger. An air-heat pump pumps the air in the pipe and in that way it makes the air circulate in the pipe. Advantageously the air-heat pump is installed directly on the outside of the outer wall and connected to the pipe in the wall. Using an air-heat pump is a relatively cheap way to install and produce heat to a low cost, which results in a cheap heating of the building. Due to the fact that the air-heat pump is connected to the pipe in the outer wall the heated air from the air-heat pump can be directed to where it is needed and distributed over the whole wall, and also be directed to several walls. In this way the heating of the building becomes more effective than if the heated air from the air pump is blown directly into the room.

According to an embodiment of the invention, the building comprises a floor and said pipe extends through the floor of the building and the pipe is arranged to heat both the floor and the outer wall. This embodiment makes it possible to both heat the walls and the floor with the same heating system. By heating the walls and floors of the building at the same time the effectiveness of the heating is increased. Also the comfort is increased for the people who reside in the building since a more smooth heat distribution is achieved inside the rooms, and also that heated floor is comfortable to walk on. According to an embodiment of the invention, the pipe is arranged in loops in the floor. The loops in the floor make it possible to cover as large area of the floor as possible, which radiates heat towards the room which is to be heated. According to an embodiment of the invention, the air in the pipe circulates from said heat exchanger in a direction where the heat first goes through the floor and then through one or more outer walls then back to the heat exchanger. The heat is greatest directly after the heat exchanger and the heat transmission is at its greatest in the floor since heat rises upwards. This means that this direction of the heat will result in a more effective heating than if the heated air would circulate in an opposite direction.

According to an embodiment of the invention, the building comprises a floor framework comprising a number of horizontal floor studs connected to the outer and inner frame parts, and the floor studs extend through the inner frame part to the outer frame part. The building comprises a floor frame work that extends through the inner frame part to the outer frame part, and is connected to the outer and inner frame parts. The floor framework connects the inner frame part to the outer frame part. The floor framework stabilizes the vertical inner studs and keeps these in place. An advantage with this embodiment is that it is possible to isolate between floor studs in the outer wall so that thermal bridges are avoided.

According to an embodiment of the invention, the building comprises a floor framework comprising a number of horizontal floor studs, and a part of said pipe is disposed between the floor studs. When using of the outer wall according to the invention, heated or cooled air is fed to the pipe and the air is transported in the pipe so that the heat or cold from the air is transferred to the inner wall element.

According to an embodiment of the invention, the building comprises an indoor ventilation system including an air outlet connected to the heat exchanger so that exhaust air from the ventilation system is used to heat or cool the air in the pipe. Thus, heat or cold from the ventilation system air is recycled, which reduces the costs for heating and cooling of the building. The pipe or pipes in the outer wall facilitate recycling of heat and cold from the ventilation system.

Brief description of the drawings The invention will now be explained more closely by the description of different embodiments of the invention and with reference to the appended figures.

Fig. 1 shows a part of a building according to a first embodiment of the invention comprising an outer wall seen from the short side of the wall.

Fig. 2 shows a cross-section A-A of the outer wall as seen from above. Fig. 3 shows a cross-section B-B of the outer wall as seen from the long side of the outer wall.

Fig. 4 shows a cross-section of a building according to an embodiment of the invention as seen from above.

Fig. 5 shows a part of a building according to a second embodiment of the invention, Fig. 6 shows a part of a building according to a third embodiment of the invention.

Detailed description of preferred embodiments of the invention

The figures 1-3 show one example of an outer wall 1 according to an embodiment of the invention. Figure 1 shows a cross-section through the outer wall seen from the short side of the wall. Figure 2 shows the outer wall seen from above in a cross-section A-A through the outer wall shown in figure 1. Figure 3 shows a cross-section B-B through the outer wall shown in figure 1 seen from the long side of the outer wall.

The outer wall 1 comprises a frame 3, an inner wall element 5 arranged on one side of the frame, an outer wall element 6 arranged on an opposite side of the frame, and an isolation layer 7 arranged between the inner and outer wall element 5, 6. The isolation layer 7 comprises a thermal insulating material. The thermal insulating material can be any type of known thermal insulating material, such as mineral wool, foam, and cellular plastic. The frame 3 comprises one or more vertical studs arranged at a distance from each other. The frame can also comprise one or more horizontal studs. One function of the frame is to support the inner and outer wall elements. In this embodiment the outer wall 1 is a double stud wall which means that the frame 3 is divided into an inner frame part 8 and an outer frame part 9. The inner wall element 5 is connected to the inner frame part 8 and the outer wall element 6 is connected to the outer frame part 9. The inner frame part 8 comprises a number of vertical inner studs 11 and the outer frame part 9 comprises a number of vertical outer studs 13. The inner and outer frame parts 8, 9 are arranged at a distance from each other so that a cavity 15 is formed between the inner and outer frame parts, namely between the vertical inner and outer studs 11, 13. The distance between the outer and inner frame parts can vary between 0.08 - 0.3 m, and typically the distance is 0.1 m. The outer and inner studs are arranged so that they form two rows of studs and the cavity 15 is formed between the two rows. The cavity 15 is filled with thermal insulating material and is a part of the isolation layer 7. Preferably, the space formed between the outer studs 13 and the outer wall element 6 is filled with thermal insulating material to achieve the isolation layer 7. The thickness of the isolation layer 7 is more than 0.08 m, preferably more than 0. 15 m and most preferably more than 0.3 m.

The outer wall may also comprise a ground beam 27 that is a horizontal beam and is arranged below a floor framework of the building, which is arranged closest to the ground. The function of the ground beam 27 is to work as a basis for the outer wall 1. The outer wall also comprises a wall plate capping 22 that is a horizontal beam connected to the lower frame part 20b, which is adapted to reinforce the outer wall 1 and connect the lower frame part 20b to the floor framework. The outer wall element 6 can comprise wind protection and an outer siding which can be made out of different materials, e.g. wood, brick, sheet, stone or grout. The inner wall element 5 comprises an inner siding made out of, e.g. plastic or wood sheets. The inner wall element 5 is directly or indirectly connected to the vertical inner studs 11, and the outer wall element 6 is directly or indirectly connected to the vertical outer studs 13.

The outer wall comprises at least one pipe 17 arranged to transfer gas, such as air to the inner wall element 5 in order to heat the interior of the building. The pipe 17 is arranged to first transfer the heat to the inner wall element 5, which then transfers the heat to one or more rooms in the building. The pipe 17 is disposed between the outer and inner wall elements 6, 5, and the pipe is disposed closer to the inner wall element 5 than to the outer wall element 6. At least the main part of the isolation layer 7 is arranged between the pipe 17 and the outer wall element 6. Preferably, the isolation layer 7 extends between the outer wall element 6 and the pipe 17. Thus, most of the heat from the pipe 17 is transferred to the inner wall element 5. In this embodiment, the pipe 17 is disposed in spaces 19 defined by the vertical inner studs 11 and the inner wall element 5.

The pipe 17 is preferably arranged in loops in the spaces 19 in order to heat as large area as possible of the inner wall element 5, see figure 3. In the shown embodiment the loops run horizontally along the height of the outer wall. It is also possible to have the loops running horizontally along the width of the outer wall. The outer wall 1 suitably comprises a vapour barrier 16 arranged between the pipe 17 and the inner wall element 5 for preventing condensation and damp to be transferred to the inner wall element. Due to the heat in the pipe, condensation is prevented from forming on the inside of the vapour barrier and therefore it prevents damp in the insulation. The vapour barrier 16 can e.g. be a plastic foil or an aluminium foil. Advantageously, the vapour barrier is made of aluminium foil, which has good properties for conducting heat and cold. Preferably, the pipe 17 is made of a material with high thermal conductivity, e.g. plastic or metal. Preferably the pipe is made out of a flexible material so that during the assembly it can be formed to loops to fit the design of the wall. The diameter of the pipe is preferably between 10 and 200 mm. The pipe can be corrugated to increase the heat dissipation ability of the pipe. However, the pipe can also be smooth.

In this embodiment, the inner frame part 8 is divided into an upper frame part 20a and a lower frame part 20b. The building has a floor framework comprising a number of floor studs 21 arranged spaced apart from each other. The floor studs 21 extend horizontally between the upper and lower frame parts 20a-b so that the lower frame part 20b supports the floor studs 21 and the upper frame part 20a rests on floor studs 21. The floor framework is connected to the outer frame part 9, as shown in figure 1. This means that the floor studs 21 are connected to the vertical outer studs 13 of the wall. The pipe 17 can be connected to an air-heat pump 23 arranged to heat or cool the air in the pipe. The air-heat pump 23 includes a heat exchanger, such as an air-to-air heat exchanger. One end of the pipe 17 is connected to an inlet of the heat exchanger and the other end of the pipe 17 is connected to the outlet of the heat exchanger. The pipe 17 and the heat exchanger form a closed system. When the air from the pipe enters the heat exchanger 23, it is heated or cooled again and pumped back into the pipe 17. The air-heat pump further includes a pump for pumping the air and by that causes the air to circulate in the pipe. The air-heat pump is used to heat or cool the air and to pump it through the pipe 17, where the air is circulating. In figure 3 the placement of the pipe 17 is shown between the vertical inner studs 11 in the space 19. The upper part of the vertical inner stud, which in figure 2 is shown as the middle stud, is shown in cross-section, and shows how the pipe is connected between the spaces 19. The pipe 17 is disposed in the spaces 19 formed between the vertical inner studs 11. Preferably, the pipe 17 is arranged in each of the spaces 19 between the vertical inner studs 11. The pipe 17 extends between two adjacent spaces 19. For example, the pipe 17 is arranged around the vertical inner studs 11, as shown in figure 2. Alternatively, the pipe 17 extends through the vertical inner studs 11.

Figure 4 shows a cross-section through a building according to an embodiment of the invention as seen from above. The building shown in the figure has only one room and four outer walls 1 of the same design as the outer wall shown in figures 1-3, and a floor 25. In this embodiment, the building comprises an air-heat pump 23 including a heat exchanger 24. The pipe 17 is connected to the heat exchanger 24 so that heated or cooled air is transferred from the heat exchanger to the pipe. One end of the pipe 17 is connected to an inlet of the heat exchanger 24 and the other end of the pipe 17 is connected to the outlet of the heat exchanger 24. The pipe 17 and the heat exchanger 24 form a closed system. The air-heat pump 23 is arranged on the outside of the building. The heat exchanger 24 is adapted to transfer energy from the air on the outside of the building to the pipe 17. The air pump 23 is arranged to pump the air from the heat exchanger to the pipe 7. In this embodiment, the pipe 17 is arranged so that it extends through the floor of the building so that it heats up both the floor 25 and the outer wall 1. In the shown example, the pipe 17 is arranged in such a way that it first extends through the floor 25, then through one or more outer walls 1 and then back to the air-heat pump 23. In an alternative embodiment, the pipe is arranged so that the pipe first extends through one or more outer walls 1, then through the floor 25, and then back to the air-heat pump. The pipe 17 is arranged in loops in the floor and functions as under-floor heating and then extends into the walls where it is also arranged in loops between the vertical inner studs 11, before the pipe 17 returns to the air-heat pump 23 where the air is heated or cooled again before it is pumped back into the pipe 17. Figure 5 shows a part of a building according to an embodiment of the invention, where the pipe 17 is designed to go through both the floor 25 and the outer wall 1.

It is also possible to transport cold air in the pipe in the wall in order to cool the room. In this way the pipe can transport heated air in the winter in order to heat the building and cold air in the summer in order to cool the building.

Figure 6 shows a part of a building according to a third embodiment of the invention. The building has an indoor ventilation system (not shown). The ventilation system comprises at least one air inlet to the building for fresh air and at least one air outlet 30 for exhaustion of used air from the building to outside the building. The ventilation system can be any type of ventilation system including an air outlet. The air outlet 30 is connected to the heat exchanger 24, for example by means of a tube 31, so that exhaust air from the ventilation system is used to heat or cool the air in the pipe 17. The heat exchanger 24 is arranged so that heat from the air outlet 30 is exchanged to the pipe 17 and thus heats the air in the pipe, and/or so that cold air from the air outlet 30 is used to cool the air in the pipe 17. The present invention is not limited to the embodiments disclosed but may be varied and modified within the scope of the following claims. For example, it is possible to use more than one pipe. The outer wall may comprise a plurality of pipes. Further, the building may comprise more than one heat exchanger 24 connected to the pipes. The building may have more than one air outlet connected to one or more heat exchangers. The pipe may also be connected to thermal solar collectors, or photovoltaic and/or thermal solar systems in order to heat the gas in the pipe. The heat exchanger can be of any known type designed to transfer heat from air to air, e.g. for transferring heat from outgoing air from the ventilation of the building to the air which is transported in the closed system through the pipe. In other embodiments there could be multiple closed systems in one building with several heat pumps and several pipes in order to increase the heat transfer to the building.