WO2011071399A2

WO2011071399A2 - The way of setting of a ground heat exchanger and a foundation built in this way

Info

Publication number: WO2011071399A2
Application number: PCT/PL2010/050062
Authority: WO
Inventors: Wieslaw Matusiak
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-12-09
Filing date: 2010-12-06
Publication date: 2011-06-16
Anticipated expiration: 2012-06-09
Also published as: WO2011071399A3; EP2510301A2; PL389842A1

Abstract

This invention relates to the way of setting of a ground heat exchanger and a foundation built in this way. According to the way, in the virgin soil (3), an impermeable vessel (1) is made, in which a ground heat exchanger (4) is placed at a small inclination angle in the direction of the outlet, and then the vessel (1) is filled with a liquid and backfill (5), preferably of the grain diameter of up to 50 mm, after which the backfill (5) is covered with film (6), onto which, preferably, a layer of sand and the foundation of the flooring are laid. The foundation has an impermeable vessel (1) placed on a base layer of sand (2) in the virgin soil (3), which houses a ground heat exchanger (4) mounted at a small inclination angle in the direction of the outlet, whereby the vessel (1) is filled with a liquid and a granular backfill (5) of the grain diameter of up to 50 mm, whereas the backfill (5) is covered with film (6), on which a layer of sand (7) and the foundation of the flooring are placed.

Description

The way of setting of a ground heat exchanger and a foundation built in this way

This invention relates to the way of setting of a ground heat exchanger and a foundation built in this way.

Heretofore, a construction of an air conditioning system is known from an American patent description US 6,810,945, according to which the system includes a gravel bed underneath the building's foundation slab, with the gravel being in contact with the ground beneath the slab and with an air stream being forced through the gravel layer.

A building air conditioning system is also known from an American patent description US 6,293,120, which includes an underground pipe buried into the base soil in order to transmit geothermal energy from the ground to the air, to control air humidity and to clean the said air. It also includes a cobble stone layer placed under the floor of a building, which makes it possible for the air to be introduced into the pipe, and a device for supplying air to the aforementioned cobble stone layer.

In the said structures cold or warm air was sucked directly into the ground and was in contact with the soil, which created favourable conditions for the growth of microorganisms, mould and fungi, the air failed to flow freely through the gravel layer and the resistance had to be compensated by the operation of higher power output fans used to obtain either warm or cold air upon its leaving the gravel layer.

In turn, a construction of a heat exchanger is known from an American patent description US 4,546,826, according to which the structure comprises a vessel which contains concentric sheet metal spirals defining two liquid flow channels between which heat exchange is effected. At both ends the vessel is closed with flat closure plates that have openings and is equipped with an internal shell surrounding the spiral. One of the closure plates has a radially outer circumferential edge surrounded by the first axially oriented opening, whereas the other closure plate has a radially inner circumferential edge which surrounds the second axially oriented opening, whereby the first opening communicates with the outer part and the second axially oriented opening communicates with the inner part of the first flow channel.

The American patent application US 20070137236 describes a construction of a ground heat exchanger utilizing geothermal energy, which comprises pipe conduits and channels mounted within a support structure. A layer of air-permeable materials is formed on the soil horizontally or at a small inclination angle, thus creating a circulation channel of the exchanger. The channel is confined by a support slab with spacer elements coupled with a construction net seated on a stabilizing net. This exchanger is equipped with an air collector.

An American patent description US 5,937,934 presents a construction of a ground heat exchanger which includes a thermo-insulated flow duct arranged in a borehole formed in ground, equipped at its end with a pump with a shroud pipe, and a return flow region for return water located radially outwardly around the shroud pipe which includes return flow pipes and a porous filling.

In turn, a ground heat exchanger known from the Polish patent application P-387406 takes the form of a tin box with inner metal radiators in the form of plates, preferably with surface development equipped with an inlet and an outlet, whereby the box is surrounded by a concrete jacket which houses perforated humidifying conduits. At the bottom of the box there is a slightly axially inclined drainage channel connected to a drain pipe finished off with a drain trap. Above the drainage channel, between the metal radiators there is at least one ceramic plate, at both ends of which there are sprinkling tubes. Depending on the manufacturing instance, the ceramic plate can be either monolithic or it can constitute a metal plate coated on both sides with ceramic tiles. Owing to the favourably high thermal conduction, the box and the radiators are made of aluminium sheet. According to the invention, the concrete jacket of a ground heat exchanger is connected to concrete piles, seated, preferably on a foundation slab, at such a depth that their bottom part is located below the level of underground waters. According to the invention the exchanger is usually installed at a depth of approximately 1.5 m.

The known constructions of ground heat exchangers and the ways of the setting thereof were characterised by a relatively slow energy exchange, while their efficiency was restricted due to the thermal properties of the materials used for the setting thereof.

According to the invention in the virgin soil an impermeable vessel is made in which a ground heat exchanger is placed at a small inclination angle in the direction of the outlet, and next the vessel is filled with a liquid and a granular backfill, preferably in granulation of a grain diameter of up to 50 mm, which ensures a free flow of the liquid and which makes it possible to carry loads for the installation of vessels underneath floorings in buildings, underneath car parks and roads. The gravel backfill is covered with film on which a layer of sand and the foundation of the flooring are placed. At the bottom of the vessel an end of the water supply system is placed along with a submersible pump, which enables constant refilling or emptying the vessel, and a device which creates a possibility of the relocation of liquid within the bed of the gravel backfill from the outlet to the inlet of the surroundings of the exchanger in order to accelerate the exchange of temperature and to counteract the freezing of elements of a ground heat exchanger, especially in the period of freezing weather. In order to increase the contact surface with the virgin soil and to accelerate the exchange of temperature, the bed of the vessel can be extended from the side of the exchanger's inlet.

The simplest method to make an impermeable vessel involves placing a film secured with geotextile fabric in an excavation previously made in virgin soil, especially covered with a base layer of sand, preferably 8-12 cm thick.

Owing to the operating conditions and the economical premises, it is preferable when the backfill of the vessel is composed of gravel, shale, stone, sand.

Moreover, due to thermal characteristics it is recommended to utilize either fresh or salt water as a liquid used to fill the vessel. The application of salt water is preferable in the case of low temperatures where fresh water might freeze.

The foundation for setting of a ground heat exchanger, made using the way according to the invention, includes an impermeable vessel made in an excavation in the ground in which a ground heat exchanger is placed at a small inclination angle in the direction of the outlet, and its filling in the form of a liquid and backfill, preferably having a grain diameter of up to 50 mm, which ensures a free flow of the liquid and which makes it possible to carry loads for the installation of vessels underneath floorings in buildings, underneath car parks and roads. The backfill is covered with film on which a layer of sand and the foundation of the flooring are placed. At the bottom of the vessel an end of the water supply system is placed along with a submersible pump, which enables constant refilling or emptying the vessel, and a device which creates a possibility of the relocation of liquid within the bed of the backfill from the outlet to the inlet of the surroundings of the exchanger in order to accelerate the exchange of temperature and to counteract the freezing of elements of a ground heat exchanger, especially in the period of freezing weather. In order to increase the contact surface with the virgin soil and to accelerate the exchange of temperature, the bed of the vessel can be extended from the side of the exchanger's inlet. An impermeable vessel can be made of a film laid on geotextile fabric in an excavation previously made in virgin soil, covered with a base layer of sand, preferably 8-12 cm thick.

The way of setting of a ground heat exchanger and building the foundation according to the invention make it possible to increase the thermal efficiency of the exchanger, to provide a more effective utilization of geothermal energy, as well as to prevent the freezing of the exchanger's elements even in conditions of severe frost.

An example of building a foundation according to the invention for setting of a ground heat exchanger is illustrated on the attached drawing which presents a cross-sectional view of the foundation with a ground heat exchanger installed within.

The foundation for setting of a ground heat exchanger, built using the way in accordance with the invention involves an impermeable vessel 1 made of film sheets made of polyvinyl chloride which is 1 mm thick. The vessel 1 is placed on a layer of protective geotextile fabric and on a base layer of sand 2 of the thickness of 8-12 cm in an excavation done in the virgin soil 3. In the vessel 1 a ground heat exchanger 4 is placed, mounted at a small inclination angle in the direction of the outlet, while the remaining volume of the vessel 1 is filled with a gravel backfill 5 of a grain diameter of at least 10-12 mm and water. The backfill 5 underneath the pipes of a ground heat exchanger 4 is 12- 15 cm thick, while the thickness of the backfill 5 covering the pipes of a ground heat exchanger 4 amounts to 25-30 cm. The backfill 5 is covered with film 6 made of polyvinyl chloride which is 0.5 mm thick, on which an external layer of sand 7, approximately 10 cm thick is laid, as well as the foundation of the flooring. The vessel 1 is equipped with a supply 8 of feed water and a pump 9 for emptying the vessel 1, as well as a pump 10 for forcing water through the bed of the backfill 5 from the outlet to the inlet of the surroundings of a ground heat exchanger 4. In order to increase the contact surface with the virgin soil 3 and to accelerate the exchange of temperature, the vessel 1, as well as the bed of the backfill 5 and water which fill it, are extended to the outside from the side of the inlet of a ground heat exchanger 4 by approximately 2 m beyond the outline of its terminal pipe.

Claims

Patent claims

1. The way of setting of a ground heat exchanger, which includes doing an excavation in the virgin soil and laying a base layer of sand and a granular backfill, characterised in that in the virgin soil (3), an impermeable vessel is made (1), in which a ground heat exchanger (4) is placed at a small inclination angle in the direction of the outlet, and then the vessel (1) is filled with a liquid and backfill (5), preferably of the grain diameter of up to 50 mm, following which the backfill (5) is covered with film (6), onto which, preferably, a layer of sand and the foundation of the flooring are laid.

2. The way according to claim 1, characterised in that the filling of the vessel (1) underneath the pipes of a ground heat exchanger (4) is at least 10 cm thick, while the pipe covering of a ground heat exchanger (4) amounts to no less than 20 cm.

3. The way according to claim 1, characterised in that in the vessel (1) a supply (8) of liquid is placed and, preferably, also a pump (9) for emptying the vessel (1), and that the vessel is equipped with a device (10) which creates a possibility of the relocation of liquid within the bed of the backfill (5) from the outlet to the inlet of the surroundings of a ground heat exchanger (4).

4. The way according to claim 1, characterised in that the device (10) for the relocation of liquid within the bed of the backfill (5) consists of a pump.

5. The way according to claim 1, characterised in that the backfill (5) is composed of gravel and/or shale and/or stone and/or sand.

6. The way according to claim 1, characterised in that the liquid is either fresh water or salt water.

7. The way according to claim 1 or 2, characterised in that the vessel (1) and its filling are extended to the outside from the side of the inlet of a ground heat exchanger (4) contained therein.

8. The way according to claim 1, characterised in that the vessel (1) is formed on a base made of geotextile fabric, by placing and combining together sheets of film made of plastic in an excavation previously done in the virgin soil (3), covered with a base layer of sand (2), preferably 8-12 cm thick.

9. The foundation for setting of a ground heat exchanger, including an excavation filled with a granular backfill, characterised in that it has an impermeable vessel (1) placed on a base layer of sand (2) in the virgin soil (3), which houses a ground heat exchanger (4) mounted at a small inclination angle in the direction of the outlet, whereby the vessel (1) is filled with a liquid and a granular backfill (5) of the grain diameter of up to 50 mm, whereas the backfill (5) is covered with film (6), on which a layer of sand is laid (7) along with the foundation of the flooring.

10. The foundation according to claim 9, characterised in that the thickness of the gravel backfill (5) underneath the pipes of a ground heat exchanger (4) amounts to at least 10 cm, while the thickness of the gravel backfill layer (5) covering the pipes of a heat exchanger (4) amounts to approximately 20 cm.

11. The foundation according to claim 9, characterised in that the backfill (5) is composed of gravel and/or shale and/or stone and/or sand.

12. The foundation according to claim 9, characterised in that the liquid is either fresh water or salt water.

13. The foundation according to claim 9, characterised in that the vessel (1) is equipped with a supply (8) of liquid and, preferably, also a pump (9) for emptying the vessel (1), as well as a pump (10) which creates a possibility of the relocation of liquid within the bed of the backfill (5) from the outlet to the inlet of the surroundings of a ground heat exchanger (4).

14. The foundation according to claim 9, characterised in that the vessel (1) and the gravel bed and liquid which fill it, are extended from the side of the inlet of the exchanger.

15. The foundation according to claim 9, characterised in that the vessel (1) is made of film (6) made of plastic which is placed on a layer of geotextile fabric in an excavation previously done in the virgin soil (3), covered with a base layer of sand (2), preferably 8-12 cm thick.