WO2009113958A1

WO2009113958A1 - System and method for heating by means of solar collector

Info

Publication number: WO2009113958A1
Application number: PCT/SE2009/050259
Authority: WO
Inventors: Niclas Ericsson
Original assignee: Niclas Ericsson
Priority date: 2008-03-13
Filing date: 2009-03-12
Publication date: 2009-09-17
Also published as: WO2009113958A9; SE0800592L

Abstract

The present invention relates to a system (1) or a method for heating of an enclosed space (2) comprising a solar collector (11), adapted to use air as heat-carrying medium, placed on the outside of the space (2), as well as a fan (13) adapted to, upon a heating of the space (2), generate an inward flow (31) of heated air from the solar collector (11) to the space (2). The present invention teaches particularly that the system (1) is adapted for a cooling down and simultaneously maintained ventilation of the space (2), that the fan (13) is adapted to generate an outward flow (32) of air from the space (2) to the solar collector (11), and that the outward air flow (32) is adapted to cool down the solar collector (11) and thereby decrease the stagnation temperature of the solar collector (11).

Description

SYSTEM AND METHOD FOR HEATING WITH SOLAR COLLECTOR

TECHNICAL FIELD

The present invention relates to a system for heating and cooling of an enclosed space comprising a solar collector adapted to use air as heat-carrying medium placed on the outside of said space, a ventilating pipe adapted to transport heated air from said solar collector to said space, as well as a fan adapted to, upon a heating of said space, generate an inward flow of heated air from said solar collector to said space. The present invention also relates to a method for heating of an enclosed space by means of a solar collector.

PRIOR ART

It has been known for a long time to transform the energy of the sun into heat by different kinds of solar collectors. The carrying medium for the heat can be a liquid or air where the medium is heated by the energy of the sun and then is transported into the space that is to be heated.

When the space in question has reached the desired temperature, such as during warm seasons, or during the warm time of the day, there are systems that turn off the solar collector, or do not make use of the energy from the solar collector, which results in a high temperature in the solar collector, a so-called stagnation temperature.

A high stagnation temperature brings about a shortened service life of the solar collector as high temperatures cause different kinds of fatigues or depletions of the different components that constitute the solar collector.

In connection with solar collectors that use air as heat-carrying medium, it is known to, in addition to the fan and ventilating duct that are used to convey the heated air from the solar collector into the space, also use an additional fan and ventilating duct in order to, during the time the solar collector is not used, convey warm air out of the space or convey cold air into the space with the purpose of cooling down the heated space. BRIEF DESCRIPTION OF THE PRESENT INVENTION

Problems

On the basis of a system according to the technical field of the present invention, and on the basis of prior art, it is a problem to, in a cost-effective way, and in a construction-wise easy way, afford a cooling down as well as simultaneously maintained ventilation of a heated space.

It is also a problem to afford a cooling down of the solar collector in the same cost-effective construction-wise simple way, and thereby a decreased stagnation temperature of the solar collector. It is a technical problem to regulate heating as well as cooling of the space.

It is also a problem to afford a balanced air-pressure, or a balanced ventilation, of the space irrespective of whether the system or the method is used to heat up or cool down the space. It is also a problem to construct a system where different components belonging to the system are placed properly on the outside of the space in relation to points of the compass and the sun's path in order to afford a good efficiency of the system.

Furthermore, it is a technical problem to afford an independent source of power for the operation of the fan belonging to the system according to the invention.

It is also a technical problem to afford a fan whereby a system according to the invention can be produced in a cost-effective and construction-wise easy way.

The Solution

With the purpose of affording a solution to one or several of the above problems, and on the basis of a system according to the technical field of the present invention, the present invention teaches that the system is adapted for a cooling down and simultaneously maintained ventilation of said space by the fan being adapted to generate an outward flow of air from the space to the solar collector, and that said outward air flow is adapted to cool down the solar collector and thereby decrease the stagnation temperature of the solar collector. Thus, the present invention teaches that the same fan and ventilating pipe are used for inward as well as outward air flow, which affords a system that, in a cost-effective and construction-wise easy way, both can heat up the space and cool down the same, where said system furthermore affords a lower stagnation temperature of the solar collector.

The present invention also teaches that the system comprises a regulating device adapted to control the fan in such a way that it generates an inward flow during heating of the space, as well as an outward flow for a cooling down of the space. Said regulating device can be realised in various ways. For instance, an automatic regulating device may comprise a thermostat adapted to regulate the fan to assume one of three different states; a first state wherein the fan generates an inward air flow if the temperature in the space falls below a first temperature, a second state wherein the fan generates an outward air flow if the temperature in the space exceeds a second temperature, where the second temperature is higher than the first temperature, as well as a third state wherein the fan is inoperative and does not generate any air flow when the temperature is between the first and second temperature.

A manual regulating device may comprise a manual switch, whereby a user can set the switch in one of three different positions in order to regulate the fan to assume one of three different states; a first state wherein the fan generates an inward air flow, a second state wherein the fan generates an outward air flow, as well as a third state wherein the fan is inoperative and does not generate any air flow. According to an additional proposed embodiment, a regulating device can be adapted to afford an automatic regulation by a thermostat as well as a manual regulation by a manual switch.

The present invention teaches that the regulating device is adapted to regulate the fan into different directions of rotation, or into an inoperative state, depending on in which state the fan is.

With the purpose of affording a balanced air-pressure in said space, the present invention teaches that the system comprises a valve adapted to maintain the balanced air pressure by letting air out of the space when the fan generates an inward air flow, and by letting air into the space when the fan generates an outward air flow.

According to the invention, the performance of the system can be improved by placing the solar collector to the south of the space where the exposure to sunlight is greatest, and by placing the valve to the north of the space where the exposure to sunlight is smallest.

An additional proposed efficiency-improving measure is that the ventilating pipe is placed in such a way that the inward air flow enters close to the floor level in the space, and that the valve is placed on the ceiling level of the space. Furthermore, the present invention suggests that the system comprises an electric solar cell, which is adapted to generate the requisite supply voltage for said fan.

With the purpose of further simplifying the construction and the efficiency of a system according to the invention, the present invention teaches that the fan is a circular axial fan adapted for installation inside said ventilating pipe.

A system according to the invention is particularly developed to co-operate with a space that consists of a building, such as a residential block or an office block.

Advantages

The advantages that foremost can be associated with a system or a method according to the present invention are that a cooling down of a space that usually is heated by a solar collector is allowed, that this can be effected with maintained ventilation of the space, and that the solar collector can be cooled down in order to lower the stagnation temperature of the solar collector. By lowering the highest stagnation temperature of the solar collector, it is also possible to lower the specifications of requirements of components included in the solar collector, which entails a saving and a possibility of producing solar collectors having the same efficiency at a lower cost and/or to develop solar collectors having an increased technical service life.

Moreover, the present invention affords these advantages by the use of only one fan and only one ventilating pipe at the solar collector, in contrast to prior art that requires two fans and two ventilating pipe in order to accomplish cooling down of the space. BRIEF DESCRIPTION OF THE DRAWINGS

A system as well as a method according to the present invention will now be described in detail, reference being made to the appended drawings, wherein: Figure 1 shows schematically and in a very simplified way a solar collector according to prior art, Figure 2 shows schematically and in a very simplified way a solar collector according to the present invention,

Figure 3 shows schematically and in a very simplified way a first proposed regulating device for a fan of a solar collector,

Figure 4 shows two different graphs that illustrate how a solar collector according to the invention can be regulated to heating or cooling, Figure 5 shows schematically and in a very simplified way a second proposed regulating device for a fan of a solar collector, Figure 6 shows a fan adapted to be used for a solar collector according to the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

With reference to Figure 1 , there is shown a known system for heating of a house A by means of a solar collector B using air as heat-carrying medium, as well as possible cooling down of the house A. Here, it is shown that a first fan B1 is adapted to be able to generate an inward air flow C1 from the solar collector B through a first ventilating pipe B2 and into the house A. Said first fan is used when a heating of the house is desired. It is furthermore shown that a second fan B3 is adapted to be able to generate an air flow C2 that can be directed out of the house A or into the house A, in the figure illustrated as an air current C2 directed into the house, through a second ventilating pipe B4 with the purpose of cooling the house A when heating is not effected.

When the second fan B3 is used, the first fan B1 is shut off and the heat generated by the solar collector B is not made use of, which entails that the temperature in the solar collector B increases, which brings about a high stagnation temperature of the solar collector.

With reference to Figure 2, now a system 1 for heating of an enclosed space 2 according to the present invention will be described, where the system 1 comprises a solar collector 11 adapted to use air as heat-carrying medium placed on the outside of the space 2. A ventilating pipe 12 is adapted to transport heated air from the solar collector 11 to the space 2. A fan 13 is adapted to, upon a heating of the space, generate an inward flow 31 of heated air from the solar collector 11 to the space 2.

The present invention teaches furthermore that the system is adapted for a cooling down and simultaneously maintained ventilation of the space, where the fan 13 is adapted to generate an outward flow 32 of air from the space 2 to the solar collector 11 , where the outward air flow 32 is adapted to cool down the solar collector 11 and thereby decrease the stagnation temperature of the solar collector 11.

The outward flow 32 is generated by the direction of rotation for the fan 13 being changed, and the present invention teaches that the system comprises a regulating device 14 for a regulation of the fan 13, where the regulating device 14 is adapted to control the fan 13 in such a way that it generates an inward flow 31 during heating of the space 2, as well as an outward flow 32 for a cooling down of the space 2.

Figure 3 and Figure 4 shows in a simplified way an example of a regulating device 14 that comprises a thermostat 15 adapted to regulate the fan 13 to assume one of three different states; a first state wherein the fan 13 generates an inward air flow 31 if the temperature T in the space 2 falls below a first temperature t1 , a second state wherein the fan 13 generates an outward air flow 32 if the temperature T in the space 2 exceeds a second temperature t2, where the second temperature t2 is higher than the first temperature t1 , as well as a third state wherein the fan 13 is inoperative and does not generate any air flow when the temperature T is between the first temperature t1 and the second temperature t2.

Figure 4a shows an example of a heating of the space 2 being effected, for instance during cold days in wintertime, early morning or late afternoon when the diurnal temperature is low but solar energy available and when a heating of the space 2 is desired. The graph in Figure 4a shows that the temperature T varies over time, where an inward heating air flow is generated as long as the temperature T in the space 2 is below the first temperature t1 and where no heating is effected when the temperature T in the space 2 exceeds the first temperature t1.

Figure 4b shows an example of a cooling down of the space 2 being effected, for instance during the daytime when the diurnal temperature is high and a cooling down of the space 2 is desired. The graph in Figure 4b shows that the temperature T varies over time, where an outward air flow is generated as long as the temperature T in the space 2 is above the second temperature t2 and where no cooling down is effected when the temperature T in the space 2 falls below the second temperature t2. The present invention also teaches that a regulating device 14 may comprise a manual switch 16, shown in a simplified way in Figure 5. The manual switch 16 can, by operation of a user, be set to one of three different positions in order to regulate the fan 13 to assume one of three different states; a first state wherein the fan 13 generates an inward air flow 31 , a second state wherein the fan 13 generates an outward air flow 32, as well as a third state wherein the fan 13 is inoperative and does not generate any air flow.

It should also be appreciated that a regulating device 14 according to the invention can be adapted to afford an automatic regulation by a thermostat 15 as well as a manual regulation by a manual switch 16. Hence, the regulating device 14 is adapted to regulate the fan 13 into different directions of rotation, or into an inoperative state, depending on in which state the fan 13 is.

With the purpose of affording a balanced ventilation of the space 2, the present invention teaches that the space 2 comprises a valve 17, schematically illustrated in Figure 2. Said valve 17 is adapted to maintain a balanced air- pressure in the space 2 by letting air out of the space 2 when the fan 13 generates an inward air flow 31 , and by letting air into the space 2 when the fan 13 generates an outward air flow 31.

With the purpose of optimizing the efficiency of the solar collector 1 1 , the present invention teaches that the solar collector 1 1 is placed to the south of the space 2, where the sun provides most energy to the solar collector 11. The present invention also teaches that the valve 17 is placed to the north of the space

2 where the entering air upon cooling down is coldest.

Furthermore, the present invention teaches that the ventilating pipe 12 is placed in such a way that the inward air flow 31 enters close to the floor level in the space 2 so as to let in warm air on the floor level where the air in the space 2 is coldest, and that the valve 17 is placed on the ceiling level of the space 2 so as to let in fresh air from outside to the space 2 up at the ceiling where the air is warmest. With the purpose of affording a self-supporting system, the present invention teaches that the system 1 also comprises an electric solar cell 18, schematically shown in Figure 2, which is adapted to generate the requisite supply voltage for the fan 13. In the figure, it is shown that the supply voltage is supplied to the fan 13 via the regulating device 14. The solar cell 18 is placed on the outside of the space and can be located in connection with the solar collector 11 but may also be placed entirely separately from the solar collector.

It is known to use different kinds of fans to generate the heat-carrying air current from a solar collector. Normally, a fan is used having a fan housing that has a quadrangular cross-section that is mounted between the solar collector 11 and the ventilating pipe 12. Figure 6 shows a fan 13 that is a circular axial fan adapted for installation inside the ventilating pipe 12. This entails that the fan 13 and the ventilating pipe 12 can be handled as a unit and is easily mounted as a part of a solar collector system.

It should be appreciated that the system 1 according to the invention may be applied in many different kinds of spaces and is not limited to be used for a certain kind of spaces. However, the most common is that the space 2 is a building, such as a residential block or an office block. The invention may naturally also be used for leisure houses that may be empty during a major part of the year, or firewood storages, boathouses, garages, basements, etc., where it is desired to have a simple, inexpensive and operationally reliable ventilation and heating of the space.

The invention also relates to a method for heating of an enclosed space, which method will be described in more detail, again with reference to Figure 2, where a solar collector 1 1 , adapted to use air as heat-carrying medium, is placed on the outside of the space 2, where a ventilating pipe 12 transports heated air from the solar collector 11 to the space 2, as well as where a fan 13, upon a heating of the space 2, generates an inward flow 31 of heated air from the solar collector 11 to the space 2, According to a method according to the invention, there are obtained a cooling down and simultaneously maintained ventilation of the space 2 by the fan 13 generating an outward flow of air 32 from the space 2 to the solar collector 11 , and that the outward air flow 32 also cools down the solar collector 11 and thereby decreases the stagnation temperature of the solar collector 1 1.

The present invention teaches that a regulating device 14, for a regulation of the fan 13, controls the fan 13 in such a way that it generates an inward flow 31 during heating of the space 2, as well as an outward flow 32 for a cooling down of the space 2. According to an embodiment wherein the regulating device 14 comprises a thermostat 15, the thermostat 15 regulates the fan 13 to assume one of three states; a first state wherein the fan 13 generates an inward air flow if the temperature T in the space 2 falls below a first temperature t1 , a second state wherein the fan 13 generates an outward air flow if the temperature T in the space 2 exceeds a second temperature t2, where the second temperature t2 is higher than the first temperature t1 , as well as a third state wherein the fan 13 is inoperative and does not generate any air flow when the temperature T is between the first temperature t1 and the second temperature t2.

According to an additional embodiment wherein the regulating device 14 comprises a manual switch 16, it is possible for a user to set the switch 16 in one of three different positions in order to regulate the fan 13 to assume one of three different states; a first state wherein the fan 13 generates an inward air flow 31 , a second state wherein the fan 13 generates an outward air flow 32, as well as a third state wherein the fan 13 is inoperative and does not generate any air flow. It is also possible to let the regulating device 14 afford an automatic regulation by a thermostat 15 as well as a manual regulation by a manual switch 16.

Thus, the present invention teaches that the regulating device 14 regulates the fan 13 into different directions of rotation, or into an inoperative state, depending on in which state the fan 13 is.

With the purpose of affording a balanced ventilation of the space 2, the present invention teaches that a valve 17 in the space 2 allows maintaining a balanced air-pressure in the space 2 by letting air out of the space 2 when the fan 13 generates an inward air flow 31 , and by letting air into the space 2 when the fan 13 generates an outward air flow 32.

With the purpose of affording an energy-wise self-supporting method, the present invention teaches that an electric solar cell 18 generates the requisite supply voltage for the fan 13.

The present invention teaches that, with the purpose of optimizing the external conditions for the method according to the invention, the heating of the solar collector 11 may be effected to the south of the space 2, which side is exposed to most hours of sunshine, and the letting in and out of air through the valve 17 can be effected to the north of the space 2, which side is coolest.

The present invention also teaches that it is possible to let the inward air flow 31 enter close to the floor level in the space 2, and that letting in and out of air through the valve 17 is effected on the ceiling level of the space 2.

The method according to the invention can be used for a ventilation and heating of many different kinds of spaces and it is well suited for spaces that are a building, such as a residential block or an office block.

It should be appreciated that the invention is not limited by the above exemplifying embodiments, and that modifications of the invention can be made within the scope of the general idea of the invention such as it is defined by the accompanying claims.

Claims

1. System for heating of an enclosed space comprising a solar collector adapted to use air as heat-carrying medium placed on the outside of said space, a ventilating pipe adapted to transport heated air from said solar collector to said space, as well as a fan adapted to, upon a heating of said space, generate an inward flow of heated air from said solar collector to said space, characterized in that said system is adapted for a cooling down and simultaneously maintained ventilation of said space, that said fan is adapted to generate an outward flow of air from said space to said solar collector, and that said outward air flow is adapted to cool down said solar collector and thereby decrease the stagnation temperature of said solar collector.

2. System according to claim 1 , characterized in that said system comprises a regulating device for a regulation of said fan, and that said regulating device is adapted to control said fan in such a way that it generates an inward flow during heating of said space, as well as an outward flow for a cooling down of said space.

3. System according to claim 2, characterized in that said regulating device comprises a thermostat adapted to regulate said fan to assume one of three different states; a first state wherein said fan generates an inward air flow if the temperature in said space falls below a first temperature, a second state wherein said fan generates an outward air flow if the temperature in said space exceeds a second temperature, where said second temperature is higher than said first temperature, as well as a third state wherein said fan is inoperative and does not generate any air flow when the temperature is between said first and second temperature.

4. System according to claim 2, characterized in that said regulating device comprises a manual switch, whereby a user can set said switch in one of three different positions in order to regulate said fan to assume one of three different states; a first state wherein said fan generates an inward air flow, a second state wherein said fan generates an outward air flow, as well as a third state wherein said fan is inoperative and does not generate any air flow.

5. System according to the claims 3 and 4, characterized in that said regulating device is adapted to afford an automatic regulation by a thermostat as well as a manual regulation by a manual switch.

6. System according to claim 2, 3, 4 or 5, characterized in that said regulating device is adapted to regulate said fan into different directions of rotation, or into an inoperative state, depending on in which state said fan is.

7. System according to anyone of the preceding claims, characterized in that said space comprises a valve adapted to maintain a balanced air-pressure in said space by letting air out of said space when said fan generates an inward air flow, and by letting air into said space when said fan generates an outward air flow.

8. System according to claim 7, characterized in that said solar collector is placed to the south of said space, and that said valve is placed to the north of said space.

9. System according to the claims 7 or 8, characterized in that said ventilating pipe is placed in such a way that said inward air flow enters close to the floor level in said space, and that said valve is placed on the ceiling level of said space.

10. System according to anyone of the preceding claims, characterized in that said system comprises an electric solar cell, which is adapted to generate the requisite supply voltage for said fan.

11. System according to anyone of the preceding claims, characterized in that said fan is a circular axial fan adapted for installation inside said ventilating pipe.

12. System according to anyone of the preceding claims, characterized in that said space is a building, such as a residential block or an office block.

13. Method for heating of an enclosed space, where a solar collector adapted to use air as heat-carrying medium is placed on the outside of said space, where a ventilating pipe transports heated air from said solar collector to said space, as well as where a fan, upon a heating of said space, generates an inward flow of heated air from said solar collector to said space, characterized in that a cooling down and simultaneously maintained ventilation of said space is obtained by said fan generating an outward flow of air from said space to said solar collector, and that said outward air flow also cools down said solar collector and thereby decreases the stagnation temperature of said solar collector.

14. Method according to claim 13, characterized in that a regulating device for a regulation of said fan controls said fan in such a way that it generates an inward flow during heating of said space, as well as an outward flow for a cooling down of said space.

15. Method according to claim 14, characterized in that said regulating device comprises a thermostat that regulates said fan to assume one of three different states; a first state wherein said fan generates an inward air flow if the temperature in said space falls below a first temperature, a second state wherein said fan generates an outward air flow if the temperature in said space exceeds a second temperature, where said second temperature is higher than said first temperature, as well as a third state wherein said fan is inoperative and does not generate any air flow when the temperature is between said first and second temperature.

16. Method according to claim 14, characterized in that said regulating device comprises a manual switch, whereby a user can set said switch in one of three different positions in order to regulate said fan to assume one of three different states; a first state wherein said fan generates an inward air flow, a second state wherein said fan generates an outward air flow, as well as a third state wherein said fan is inoperative and does not generate any air flow.

17. Method according to the claims 15 and 16, characterized in that said regulating device affords an automatic regulation by a thermostat as well as a manual regulation by a manual switch.

18. Method according to claim 14, 15, 16 or 17, characterized in that said regulating device regulates said fan into different directions of rotation, or into an inoperative state, depending on in which state said fan is.

19. Method according to any one of claims 13 to 18, characterized in that a valve in said space affords that a balanced air-pressure is maintained in said space by letting air out of said space when said fan generates an inward air flow, and by letting air into said space when said fan generates an outward air flow.

20. Method according to claim 19, characterized in that the heating of said solar collector is effected to the south of said space, and that letting in and out of air through said valve is effected to the north of said space.

21. Method according to the claims 19 or 20, characterized in that said inward air flow enters close to the floor level in said space, and that letting in and out of air through said valve is effected on the ceiling level of said space.

22. Method according to any one of claims 13 to 19, characterized in that an electric solar cell generates the requisite supply voltage for said fan.