US20080164333A1

US20080164333A1 - Heating System And A Method For Heating

Info

Publication number: US20080164333A1
Application number: US11/886,095
Authority: US
Inventors: Sten Engwall; Per-Ake Engwal Von Scheele
Original assignee: Semako AB
Current assignee: Semako AB
Priority date: 2005-03-16
Filing date: 2006-02-24
Publication date: 2008-07-10
Also published as: SE0500597L; WO2006098691A1; SE531216C2; EP1869369A1

Abstract

The invention relates to a building heating system which includes an insulated foundation (9) beneath the lowermost (12) of the building. According to the invention, the system comprises at least one heat pump (1, 2) that includes a heat absorbing side (2) located in the foundation space (9). The system also includes means (23) for distributing air from the foundation space (9) to spaces situated above the floor (12). The system also includes means (7) for delivering external air to the foundation space (9). The invention also relates to a method of heating a building.

Description

FIELD OF INVENTION

In a first aspect the present invention relates to a building heating system that includes an insulated foundation space beneath the lowermost floor of the building.
In a second aspect the invention relates to a method of heating a building that includes such a foundation space.

BACKGROUND OF THE INVENTION

It is known to provide a building with an insulated foundation space beneath the lowermost floor of the building, and to use this space, or area, in heating the building, among other things. Such a system is described in SE 468441. The building foundation described in this patent specification implies a radically novel concept with regard to heating of a building and also with regard to other service requirements where an overall perspective has created possibilities of achieving an improved building heating and running economy.
It has long been known to heat buildings with the aid of a heat pump.
A heat pump utilizes the energy stored in a low-temperature medium to produce a medium of higher temperature, which requires an energy input, normally electrical energy. The low temperature medium may be rock, earth, water, or air, whereas the medium of higher temperature is usually air. In the case of the instant application, by an air-air-heat pump is meant a heat pump in which the low temperature medium is air, i.e. air is the heat emitting medium, and where the medium of higher temperature, i.e. the heat absorbing medium, is also air. The amount of energy won from the emitting medium is normally from three to four times greater than the energy supplied for carrying out the process.
The energy is won with the aid of a closed circuit that includes an evaporator, a compressor, a condenser, and an expansion valve. A heat carrying medium that has appropriate properties with regard to boiling point, etc., passes cyclically through the circuit. The heat carrying medium is passed to the evaporator in the form of cold liquid, wherein heat is delivered to the liquid by the heat emitting medium and caused to vaporize. The cold vaporized heat carrying medium is then passed to a compressor in which it is compressed to a high elevated pressure. The heat carrying medium is then allowed to pass through a condenser in which the medium condenses to a liquid form while giving off heat to the heat absorbing medium. The liquid is then passed via an expansion valve to the evaporator, for renewal of the cycle. Typical heat carrying mediums are halogenated hydrocarbons, such as Freon^R.
Since the heat pump principle is generally known, the above summarization is deemed to be an adequate account of this principle in the present context.
When a building is heated with the aid of an air-air-heat pump, the heat-emitting medium will normally be air taken from outside the building. Although being beneficial due to the fact that the amount of air available is unlimited, this air has the drawback of being relatively cold, particularly during those periods when heating requirements are at their maximum, i.e. during the winter months and during nighttimes.
It is also known to use the exhaust air of the building as the heat emitting medium. This has the benefit of recovering the energy in this relatively warm air. The drawback is that this air is not sufficient to satisfy the heating requirement, thereby necessitating the heating requirement to be supplemented with further heating devices, for instance wood or fossil fired boilers, electric heaters or an additional heat pump. This results in higher system investment costs due to the requirement of more than one heating unit.
The object of the present invention is to provide a heating system that affords better heating economy than that achieved with conventional heating systems and which also provides a healthier living environment in the building.
In this present patent application the term external air refers to the air taken from outside the building, the term exhaust air refers to the air exited from the building but still located within its climatic shell and extract air refers to air extracted from the exhaust air when said air has left the climatic shell of the building.

SUMMARY OF THE INVENTION

The object of the invention is achieved in accordance with the first aspect thereof through the medium of a heating system of the kind in question that includes the special features of comprising at least one heat pump with a heat emitting side situated in the insulated or isolated foundation space, means for distributing air from the foundation space to spaces situated above the lowermost floor, and means for delivering external air to the foundation space.
The inventive system enables such a foundation space to be used to an optimum and affords various benefits with regard to heating economy, comfort and health.
Because the heat emitting part of the heat pump is placed in the foundation space instead of in the living space, there is no need to take-up variable living space for this part of the heat pump.
When the heat pump is situated in a living space it will normally result in solely local heating in which the heat pump is situated, whereas, in the case of the inventive system, warm air is distributed from the foundation space to the various spaces of the buildings. A heat pump placed in the building will mean that used air is also recycled, something that is avoided with the system constructed in accordance with the invention. The relative humidity of the incoming external air is reduces as it enters the building and the air is warmed in the foundation space, therewith avoiding condensation and also reducing the risk of mould and decay.
The air heated in the foundation space layers so that the warmest air rises and warms the underside of the floor, which may be insulated. This results in heating of the floor in the lowermost floor of the building. The air that is distributed to the living spaces of the building will thus be relatively clean and healthy.
Because the spaces in the building are warmed or heated by air that is distributed from the foundation space it will mean that this air will have a temperature that only slightly exceeds the final temperature of the heat carrier, therewith resulting in minimum heat losses.
Due to the more effective use of heat, the air exchange in the building can be increased while retaining good heating economy, which also engenders a further healthy aspect.
The lowermost floor will preferably be insulated.
According to one preferred embodiment of the invention, the distribution means include gaps between the floor of the building and the walls thereof.
Due to such designed distribution means, there is obtained a low flow rate and uniform heating. The gaps eliminate the need of ventilation channels, which tend to gather dirt and dust and therefore create health hazards. Because the gaps may be given a very large through-flow-space so that the flow rate of the air will be lower than in typical ventilation channels, there is achieved effective sedimentation of dirt particles.
According to another preferred embodiment of the invention, the system includes a fan or blower mounted in the foundation space.
A fan or blower enables the external air supplied to be brought into communication with the heat-emitting side of the heat pump in an effective manner.
According to another preferred embodiment, the distribution means includes at least one air conduit that has an inlet opening in the foundation space, wherewith the position of said opening is variable. Because the position of the inlet opening can be varied, the opening can be placed at different levels in the foundation space or at different distances from the fan. The temperature of the air that flows into the air conduit will thus differ in accordance with the position in which the inlet opening is placed. Air that passes up in the building along this path can therewith be used to regulate the temperature in the space into which the outlet of the conduit opens. According to a further preferred embodiment of the invention, the heat pump has a heat absorbing side which is structured for air as the heat emitting medium. This is normally the cheapest heat absorption solution and is sufficiently effective within a wide range of external temperatures down to about 0° C.
According to another preferred embodiment of the invention, the heat absorbing side of the heat pump is structured for external air as the heat emitting medium.
According to another preferred embodiment of the invention, the heat absorbing side of the heat pump is structured for extraction air as the heat emitting medium.
According to a further preferred embodiment of the invention, the heat absorbing side of the heat pump is structured for the simultaneous use of both external air and extraction air as the heat emitting medium.
Although the preferred embodiments mentioned above in the nearest paragraphs have desirable benefits they also have drawbacks to some extent. In certain cases and in certain climate conditions a purely external air heat pump will provide a satisfactory solution. The alternative option of a purely extract-air-heat pump has its benefits but also significant limitations.
The alternative option of an air heat pump of which both external air and extracted air is used as a heat emitting medium constitutes an option of combining the benefits afforded by respective media while of significantly eliminating their drawbacks.
Because the heat pump utilizes warm exhaust air and external air, the energy contained in the exhaust air is recovered while, at the same time, achieving the necessary volume of air by also utilizing external air. This results in an optimal heat economy. Because this is achieved in one single unit, there is a significant saving in the investment costs of the heating system. The combined result is a total building heating economy that is more beneficial than what has been achievable hitherto.
Another benefit afforded by the inventive system is that there is less risk of freezing on the heat absorbing side of the heat pump than in the case of a heat pump with which solely external air is used.
According to another preferred embodiment of the invention, the heat absorbing side of the heat pump is structured for a mixture of external air and extracted air as the heat emitting medium.
The design of the heat absorbing side of the heat pump is simplified when both external air and extraction air is utilized.
According to another preferred embodiment of the invention, the heat absorbing side of the heat pump is structured for water and/or earth as the heat emitting medium.
One gain with this type of heat pump is that the supply of heat will be generally constant regardless of the outside temperature, and that the pump efficiency will remain at a constant level. The benefits afforded by a heat pump of this kind are greatest when the climate conditions are such that the advantages afforded by this heat pump will outweigh the higher investments costs related to such a pump.
According to another preferred embodiment of the invention, the system includes means for switching between different operational states of the heat pump, these operational states comprising:
The use of solely air as the heat emitting medium;
The use of solely water and/or earth as the heat emitting medium;
The use of both air and water and/or earth as the heat emitting medium.
This enables the system to be optimized and adapted to the type of heat source that is most appropriate, depending on temperature and other operational conditions.
According to another preferred embodiment of the invention, the system includes at least one heat carrying conduit disposed in the ground beneath the foundation space and connected to the heat absorbing side of the heat pump.
This enables the heat contained in the relatively warm ground beneath the foundation space to be utilized.
According to another preferred embodiment of the invention, the system includes means for heating the ground beneath the foundation space.
This enables heat to be taken from different kinds of heating sources and stored in the ground and then taken from the ground when there is need to supply heat to the heat pump.
According to another preferred embodiment of the invention, the system includes a solar panel and/or a hearth and heat transfer means for transferring heat from the solar panel, the hearth and/or the foundation space to the ground situated beneath the foundation space.
Heat produced from the solar panel or the hearth during periods at which the heat generated thereby exceeds the heat required to heat the building at that moment in time can thereby be utilized and stored in the ground beneath the foundation space. This heat can then be recovered at cold temperature conditions and delivered to the heat absorbing side of the heat pump.
The object of the invention has been achieved in accordance with the second aspect of the invention by means of a method of the type concerned which comprises the special steps of disposing the heat emitting side of a heat pump in the foundation space and by distributing air from the foundation space to spaces situated above the lowermost floor of the building and delivering external air to the foundation space.
According to another preferred embodiment of the inventive method, the method is carried out with the aid of a heating system according to the invention or according to preferred embodiments thereof.
The benefits afforded by the inventive method are of a corresponding kind to the above benefits afforded by the inventive heating system and preferred embodiments thereof. The invention will now be described in more detail with reference to following beneficial embodiments thereof and also with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view of the lower part of a building that includes a heating system according to the present invention;

FIG. 2 is a schematic view from above the foundation space of the building shown in FIG. 1;

FIG. 3 is a sectional view corresponding to FIG. 1 and illustrating an alternative embodiment; and

FIG. 4 illustrates a detail of an exemplifying embodiment of the invention

DESCRIPTION OF BENEFICIAL EMBODIMENTS

FIG. 1 is a sectional view of the lower part of a building that is equipped with a heating system according to the present invention. The walls 13 of the building rest on a so-called cottage foundation 11. Lowermost in the building is an insulated foundation space which is delimited from the remainder of the building by the lowermost floor 12 of the building. The air present in the foundation space is heated with the aid of a heat pump 1, 2, where the heat emitting part 2 thereof, i.e. its condenser, is situated in the foundation space. The heat absorbing part 1 of the pump, i.e. its evaporator, is located outside the building. The heat pump 1,2, of the illustrated example is an air-air-heat pump and thus obtains its heat from air, which may be external air, air extracted from the building or a combination of such air.
External air is delivered to the foundation space 9 as supply air, via a conduit 7 and with the aid of a blower of fan 8. The conduit 7 is positioned so that the external air will be blown directly onto the heat emitting part 2 of the pump. In principle, all incoming air will contact the heat emitting part 2 of the pump and therewith heated thereby prior to being spread throughout the foundation space 9. Heated air will therewith be delivered to the building interior, i.e. its foundation space 9. Because the supply air is heated by the heat emitting part of the pump, the relative humidity of this air will be lowered so that no condensation is formed. This ensures that no moisture and mould will form in the foundation space.
The foundation space 9 is insulated against the ground S beneath the foundation space by means of an insulating layer 10 covered by a radon fabric 16 and surrounded by a cottage foundation that includes insulating walls. The foundation space 9 is therewith enclosed within the climate shell of the building.
The air heated by the heat emitting part 2 of the heat pump will layer so that the warmest air will rise up towards the underside of the floor 12, therewith warming the floor. The somewhat colder, although heated, air will sink to the bottom of the foundation space. Movement of the air in the foundation space 9 is relatively slow. Consequently, dirt and other contaminants that accompany the supply air will fall down onto the bottom and collect on the radon fabric 16. This fabric can be cleaned as required, for instance by rinsing off its surface. Located between the floor 12 and surrounding walls 13 are gaps 14 which function as distribution means for passage of the heated air in the foundation space 9 to the floor above the floor 12. When the building includes several floors, or stories, corresponding gaps will be provided between respective floors.
FIG. 2 shows the described foundation space from above.
FIG. 3 is a sectioned view similar to that shown in FIG. 1, and illustrates an alternative embodiment of the system, which includes functions additional to those described above. Those components of the FIG. 3 embodiment that find correspondence in the FIG. 1 illustration are identified by the same reference signs as those used in FIG. 1. The heat absorbing part 1 of the heat pump is structured to be heated in this case by both external air and extracted air. The exhaust air is lead through an exhaust air conduit from the rooms of the building and down to the foundation space and from there through the conduit 3A to the heat absorbing part 1 of the pump. The inlet of the exhaust air conduit may comprise a bathroom valve for instance.
Circulation of the exhaust air can be enhanced, by including a blower or fan 5 in the exhaust air conduit 3.
There is arranged in the foundation space 9 a heat exchanger 22 which is adapted to bring the exhaust air in the conduit 3 into heat-exchanging relationship with the supply air in the conduit 7. Thus, as the supply air flows into the foundation space 9 through the outlet 7 a, it is pre-heated and then heated still further as it approaches the heat absorbing part 2 of the pump.
The heat contained by the exhaust air is recovered with this arrangement in two stages, firstly in the heat exchanger 22 and then in the heat emitting part 1 of the pump.
In addition to the circulation of heat that takes place to the spaces above the floor 12 via said gaps 14, the system shown in FIG. 3 is supplemented with an air conduit 23 that leads to one of the spaces. The conduit 23 includes an inlet part 23 a which is telescopically displaceable so as to enable the inlet opening 23 to be moved to different height positions in the foundation space 9. When desiring cooler air in the space concerned, the inlet opening 23 b is moved down towards the lower part of the foundation space where the temperature is lower so that somewhat cooler air will flow up through the air conduit 23.
The system shown in FIG. 3 also includes means that can be moved down into the ground S beneath the foundation space 9 and store heat contained in the ground. A conduit 24 is buried in the ground to this end.
The conduit 24 communicates with a heat exchanger 25. Heat is delivered to the heat exchanger 25 from a hearth 27, via a conduit system 26. The heat carrying medium in the conduit 26 may be air, steam or water. The conduit system 26 includes an adjustment valve or switch 34 through which a conduit branch can be brought into communication with the heat exchanger 25. This enables the air in the foundation space 9 to be utilized as a source of heat to the heat exchanger 25 during those periods in which surplus heat is generated in the foundation space, such as may be the case during the summer months.
Alternatively, surplus heat can be passed directly from the foundation space 9 into the ground through pipes, so as to heat the ground.
The system illustrated in FIG. 3 also includes a heat-generating solar panel 29. The solar panel is connected to the heat exchanger 25 by means of a heat carrying conduit 28, wherewith the heat carrier may be air or water.
Heat may be supplied to the heat exchanger 25 through the medium of a conduit system that conducts tap water from the building to the heat exchanger 25.
It will be understood that the heat sources described above for supplying heat to the heat exchanger 25 can be used individually or in different combinations with one another. The climatic zone and other conditions will decide which combination is optimal in each individual case.
Although it has been inferred for the sake of simplicity that all heat sources deliver heat to one and the same heat exchanging unit 25, it will be understood that each heat source may serve a separate heat exchanger.
The conduit 24 that provides a heat carrier circuit for the heat to be transported from the heat exchanger 25 to the ground S may be structured for air, water and/or steam, depending on the nature of the heat source used. The primary heat carrier will be steam when the heat source is comprised of the hearth 27 while in other cases water is the most suitable heat carrier.
The heat emitting side of the heat pump 1, 2 may include a conduit which leads air to the ground S during periods at which the heat pump produces more heat than is required to heat the building.
The heat in the ground S can be taken with the aid of a separate conventional ground heat pump. Alternatively, ground heat can be recovered by providing the heat emitting part 2 of the air-air-heat pump 1, 2 with a heat absorbing part 32 that is comprised of a heat exchanger which takes up water-carried heat from the ground S via a conduit 33.
In the FIG. 3 illustration the conduit 24 has been shown to comprise horizontal loops in the ground S. Alternatively, the conduit loops may be disposed vertically and caused to extend down to a much greater depth. This may, in many cases, result in reduced excavation costs incurred by digging deep and narrow holes as compared with shallow and broad holes?.
FIG. 4 is a schematic illustration of an embodiment of the heat absorbing part 1 of the heat pump with which both external and extraction air is used as a heat emitting medium.
In the case of the FIG. 4 embodiment, extraction air B from the exhaust air conduit and external air A is led into a mixing chamber 18, which may have the form of a hood that connects with the external part 1 of the heat pump. The mixture of extraction and external air is then delivered to the external part 1 of the pump. Mixing of the air may be made more effective prior to the airflow entering the external part 1, by providing a shielding element 19. The volume of external air A delivered is regulated by a butterfly valve 17. The valve may be controlled automatically, depending on the volume of incoming extraction air B.
Although the system described has been referred to as a heating system throughout, which is the main function of the system, it will be understood, however, that the system can also be used to cool the spaces in a building and thus in reality constitutes a conditioning system.

Claims

1. A building heating system which comprises an insulated foundation space (9) situated beneath the lowermost floor (12) of the building, wherein at least one heat pump (1,2) that has a heat emitting side (2) located in the foundation space (9), means (14, 23) for distributing air from the foundation space (9) to spaces located above said lowermost floor (12), and means (7) for delivering external air to the foundation space.

2. A heating system according to claim 1, wherein the air distribution means (14, 23) include gaps (14) between said floor (12) and the walls (13) of the building.

3. A heating system according to claim 1, including a fan or blower (8, 34) mounted in the foundation space (9).

4. A heating system according to claim 1, wherein the air distribution means (4, 23) include at least one air conduit (23) that has an inlet opening (23 b) which is disposed in the foundation space (9) and the position of which can be varied.

5. A heating system according to claim 1, wherein the heat pump (1,2) has a heat absorbing side (1) which is structured for air as the heat emitting medium.

6. A heating system according to claim 5, wherein the heat absorbing side (1) of the heat pump (1,2) is structured for external air as the heat emitting medium.

7. A heating system according to claim 5, wherein the heat absorbing side (1) of the heat pump (1,2) is structured for extracted air as the heat emitting medium.

8. A heating system according to claim 5, wherein the heat absorbing side (1) of the heat pump (1,2) is structured to use simultaneously both external air and extracted air as the heat emitting medium.

9. A heating system according to claim 8, wherein the heat absorbing side (1) of the heat pump (1,2) is structured for a mixture of external and extracted air as the heat emitting medium.

10. A heating system according to claim 5, wherein the heat absorbing side of the heat pump (1, 2) is structured for water and/or earth as the heat emitting medium.

11. A heating system according to claim 10, wherein the system includes control means for switching between different operational states of the heat pump (1,2) said operational states include the use of solely air as a heat emitting medium; the use of solely water and/or earth as the heat emitting medium; and the use of both air or water and/or earth as the heat emitting medium.

12. A heating system according to claim 11, wherein the system includes at least one heat carrying conduit (33) disposed in the ground (S) beneath said foundation space, this heat carrying conduit being joined to the absorbing side (32) of the heat pump (1).

13. A heating system according to claim 12, wherein the system includes means (24) for heating the ground (S) beneath the foundation space (9).

14. A heating system according to claim 13, wherein the system includes a solar panel (29) and/or a hearth (27) and heat transfer means (25, 26, 28, 35) adapted to transfer heat from the solar panel (29), the hearth (27) and/or the foundation space (9) to the ground (S) beneath the foundation space (9).

15. A method of heating a building that includes an insulated foundation space beneath the lowermost floor of the building, comprising the steps of placing a heat emitting side of a heat pump in said foundation space, distributing air from the foundation space to spaces situated above said floor, and delivering external air to the foundation space.

16. (canceled)