Surface geothermal heat pump and its installation process

Abstract

The pump (20) comprises a refrigerant circuit, an evaporator with a portion (22) of the circuit installed in the ground (21), a compressor, a condenser, and an expansion valve. This portion (22) includes at least one tubular element with a free end (25) in the ground (21) and an above-ground end (26) communicating with the expansion valve and the compressor. The element (22) has a first channel from the above-ground end (26) to the free end (25) communicating with the expansion valve and a second channel from the free end (25) to the above-ground end (26) communicating with the compressor. The element (22) has been anchored obliquely in the ground (21). (See abstract figure: Figure 2)

Description

Title of the invention: Surface geothermal heat pump and its installation method technical field

[0001] The field of the invention relates to heat pumps.

[0002] The principle of a heat pump, illustrated in [Fig.1], is based on a refrigerant fluid, whose boiling point is very low, to which the heat from an ambient environment 2 is transferred in a first heat exchanger 3, in which the refrigerant vaporizes 4.

[0003] This exchanger is called an evaporator.

[0004] The gaseous refrigerant 4 is compressed in a compressor 5 and heated strongly.

[0005] The high-temperature gaseous refrigerant 6 then passes into a second heat exchanger heat 7 in which its heat is transferred to a heat accumulator of the heating system connected to a heat distribution circuit in the rooms to be heated 8. The refrigerant, in the second exchanger 7, is therefore cooled and liquefied. This second exchanger is called the condenser.

[0006] The pressure of the cooled refrigerant 9 exiting the condenser 7 is reduced in an expansion valve 10 where its temperature is further lowered to that which it must have in the evaporator 3.

[0007] The heat exchangers, the compressor and the expansion valve form the refrigeration circuit of the heat pump.

[0008] It should be noted, but without going into further theoretical considerations, that a heat pump can be considered as a heating system, if one wishes to increase the temperature of the hot source, as well as a refrigeration system, if one wishes to lower the temperature of the cold source, which is implemented in an air conditioner or refrigerator.

[0009] The invention relates more particularly to geothermal heat pumps, in which the ambient environment is the ground, which then constitutes the evaporator through which the refrigerant circulates. These heat pumps are of two types. Deep geothermal heat pumps allow for the recovery of a significant amount of heat regardless of the outside temperature, but require drilling to great depths, between 100 and 4000 meters. Drilling and repairs are expensive, and leaks are very harmful to the environment.

[0010] Shallow geothermal heat pumps that recover heat from the ground surface, by means of vertical pipes of 5 to 10m, or vertical coils arranged in the ground at a depth of 30cm to 10m, or horizontal coils laid in the ground at a depth of 20cm to 2m.

[0011] These latest heat pumps are mainly used in single-family homes. However, they have the disadvantage of requiring trenches to be dug for the refrigerant network, which is expensive and damages gardens. Repairing leaks and replacing parts is also not easy.

[0012] The problem of the invention of the present application is therefore to propose a surface geothermal heat pump whose installation is quick, economical, adapted to possible obstacles and particular surfaces and whose maintenance can be carried out quickly, without damage and cheaply.

[0013] To this end, the invention relates to a surface geothermal heat pump comprising a refrigerant flow circuit, an evaporator with a portion of the refrigerant flow circuit installed in the ground, a compressor, a condenser and an expansion valve, the condenser being intended to be connected to a heating circuit of a room to be heated, characterized in that said portion of the refrigerant flow circuit comprises at least one tubular element with a free end introduced into the ground and an aerial end communicating with the expansion valve and the compressor, said tubular element comprising a first flow channel from the aerial end to the free end communicating with the expansion valve and a second flow channel from the free end to the aerial end communicating with the compressor.

[0014] Thus, it is easy and quick to push the tubular element into the ground by its free end, by tilting it relative to the ground surface, without having to dig a trench and therefore without the slightest degradation of the soil.

[0015] In the preferred embodiment of the heat pump of the invention, said portion of the refrigerant flow circuit comprises a bundle of similar tubular elements arranged in series, the flow channel from the air end of the first element to its free end communicating with the expansion valve, the flow channel from the free end of the last element to its air end communicating with the compressor, the flow channel from the air end of an element to its free end being connected to the flow channel from the free end to the air end of the preceding element.

[0016] Advantageously, the tubular elements are arranged in a star shape.

[0017] A tubular element may comprise a single channel folded back on itself into two parts forming respectively the two flow channels.

[0018] A tubular element may include a central tubular portion forming the flow channel for the heated refrigerant from the free end to the air end, the flow channel for the refrigerant to be heated from the air end to the end free being formed by the annular part of the tubular element surrounding the central tubular part.

[0019] The free end of a tubular element introduced into the ground can be tapered and threaded so that the element can be screwed into the ground.

[0020] The aerial end of a tubular element can be arranged so that it can be driven by a screwing member.

[0021] The invention also relates to a method of installing a heat pump as presented above, characterized in that, having installed the compressor, the condenser and the expansion valve, in order to install in the ground the portion of the refrigerant flow circuit, at least one tubular element of said portion of the refrigerant flow circuit is anchored obliquely in the ground by its said free end, and its said aerial end is connected to the expansion valve and the compressor.

[0022] The inclination of the tubular element must depend on the nature of the ground, which may, for example, be earth, sand, or even rocky ground.

[0023] Advantageously, to anchor the tubular element in the ground, a hole is first drilled, with a length substantially equal to that of the tubular element, and then the tubular element is inserted into the hole.

[0024] If the tubular element has a tapered and threaded free end, the anchoring of the tubular element is completed by screwing it into the bottom of the hole.

[0025] Preferably, to install the portion of the refrigerant fluid flow circuit in the ground, a plurality of similar tubular elements are anchored obliquely in the ground, they are connected together in pairs, the first flow channel is connected to the expansion valve at the aerial end of the first tubular element of said plurality and the second flow channel is connected to the compressor at the aerial end of the last tubular element.

[0026] Preferably, the plurality of tubular elements is arranged in a star-shaped bundle.

[0027] It should be noted that generally, for good heat recovery from the ground, tubular elements with a length of about ten meters will be used.

[0028] The invention will be better understood upon reading the following description, with reference to the attached drawing, in which • [Fig.1] schematically represents a standard heat pump; • [Fig.2] is an illustration of a first embodiment of the heat pump of the invention, in which the refrigerant flow circuit comprises a single tubular element; • [Fig.3] is a schematic top view of a refrigerant fluid flow circuit with several tubular elements arranged in a star, of another embodiment of the heat pump of the invention; • Figure 4 is a schematic cross-sectional view of a first embodiment of a tubular element of a refrigerant flow circuit for the heat pump of the invention and • Fig. 5 is a schematic cross-sectional view of a second embodiment of a tubular element of a refrigerant fluid flow circuit of the heat pump of the invention.

[0029] Any embodiment of the surface geothermal heat pump of the invention 20 comprises the classic elements 3, 5, 7, 10 of a heat pump as described in the preamble to this application with reference to [Fig. 1], except that the first exchanger 3 does not receive heat from the ambient environment, but from the ground 21.

[0030] In the embodiment of [Fig.2], the pump 20 includes a refrigerant fluid flow circuit, the portion of which installed in the ground 21 comprises only one tubular element 22. For this purpose, a hole 23, of a length substantially equal to that of the element 22, was previously drilled obliquely into which the tubular element 22, thus anchored in the ground 21, was then inserted in an inclined position relative to the surface 24 of the ground 21.

[0031] The tubular element 22 has a free end 25, through which it was introduced into the hole 23, and an aerial end 26 connected to the regulator 10 and the compressor 5.

[0032] With reference to the embodiment of [Fig.4] of the tubular element 22', the latter comprises a first channel 27' for the flow of the refrigerant fluid from the air end 26' to the free end 25', communicating with the expansion valve 10, and a second channel 28' for the flow of the fluid from the free end 25' to the air end 26', communicating with the compressor 5.

[0033] The second channel 28', for the flow of the refrigerant, heated by the heat of the ground, from the free end 25' to the air end 26', is formed in the central tubular part of the element 22' which is delimited by a thermally insulating wall 30' and which extends inside the annular part of the element 22', in which is formed the first channel 27' for the flow of the refrigerant fluid to be heated by the heat of the ground and which therefore surrounds the second channel 28'.

[0034] It should be noted that the free end 25' of the element 22' is tapered and threaded, which allowed the element to be screwed into the ground for anchoring. Similarly, the aerial end 26' of the element 22' is arranged to allow it to be driven by a screwing element and to have, for example, a polygonal contour.

[0035] In the bottom of the tubular element 22', near its tip 25', an annular non-return valve 29' has been disposed, preventing the refrigerant fluid to be heated from rising back up into its flow channel 27'.

[0036] With reference to the embodiment of [Fig. 5] of the tubular element 22”, it has exactly the same external shape as the element 22', with its free end tip 25” and its aerial end 26”.

[0037] In contrast, the interior of the element 22" comprises only one channel, but folded back on itself into two parts, separated by a thermally insulating partition 30", and forming respectively the two flow channels, connected respectively to the expansion valve 10 and the compressor 5, 27" of the fluid to be heated, and 28" of the heated fluid. In the bottom of the tubular element 22", near its tip 25", but only in the part of the channel 27", a simple non-return valve 29" is provided to prevent the refrigerant to be heated from flowing back into its flow channel 27".

[0038] It should also be noted that the angle of inclination of the tubular element 22 (22',22") can vary depending on the nature of the terrain.

[0039] In the preferred embodiment of [Fig.3], the pump, of which only the portion 40 installed in the ground of the refrigerant flow circuit has been shown, is identical to that of [Fig.1], except for this portion 40 of the refrigerant flow circuit.

[0040] The portion of the circuit 40 comprises a star-shaped bundle of tubular elements 22 all similar to one or the other of the elements 22',22" of figures 4,5.

[0041] In the example shown, the first exchanger here comprises 8 tubular elements anchored in the ground like that of the embodiment of the pump in [Fig.2].

[0042] The bundle 40 comprises a first tubular element 41 and a last tubular element 48, here the eighth.

[0043] The eight tubular elements 41-48 are arranged in series connected in pairs. Thus, the flow channel from the air end 51 of the first element 41 to its free end 61 is connected to the expansion valve 10; the flow channel from the free end 71 of the last element 48 to its air end 81 is connected to the compressor 5.

[0044] The flow channel from the aerial end 261 of one of the seven tubular elements following the first to its free end 262 is connected to the flow channel from the free end 263 to the aerial end 264 of the preceding element.

[0045] The connection of the tubular elements to each other, by their aerial ends, is made through a distributor 90 via the shortest possible circuits.

[0046] It will be noted that the connections of the flow channels to the expansion valve and the compressor, in all figures 2-5, are illustrated by arrows referenced 5 and 10 directed towards these two elements 5 and 10 of the pump.

[0047] It is interesting to note that the sealing of the flow channels of the tubular elements is easy to check, their aerial ends being grouped in an area very close to the distributor 90.

[0048] To replace a tubular element, it is enough to remove it from its hole, unscrewing it as appropriate, and anchoring another non-defective one in it.

[0049] It is an easy and quick operation.

[0050] Figure 3 shows a bundle of tubular elements of substantially the same length. Of course, this is by no means a limiting feature of the invention. The bundle 40, depending on the nature and structure of the soil, may naturally include tubular elements of different lengths and, of course, different inclinations.

Claims

Demands

1. A shallow geothermal heat pump (20) comprising a refrigerant flow circuit, an evaporator (3) with a portion (22, 40) of the refrigerant flow circuit installed in the ground (21), a compressor (5), a condenser (7) and an expansion valve (10), the condenser (7) being intended to be connected to a heating circuit of a space to be heated (8), characterized in that said portion of the refrigerant flow circuit comprises at least one tubular element (22; 22'; 22") with a free end (25) introduced into the ground (21) and an above-ground end (26) communicating with the expansion valve (10) and the compressor (5), said tubular element (22) comprising a first flow channel (27'; 27") from the above-ground end (26'; 26") to the free end (25'; 25") communicating with the regulator (10) and a second flow channel (28';28") from the free end (25';25") to the air end (26';26”) communicating with the compressor (5).;

2. Heat pump according to claim 1, wherein said portion (40) of the refrigerant flow circuit comprises a bundle of similar tubular elements (41-48) arranged in series, the flow channel from the air end (51) of the first element (41) to its free end (61) communicating with the expansion valve (10), the flow channel from the free end (71) of the last element (48) to its air end (81) communicating with the compressor (5), the flow channel from the air end (261) of an element to its free end (262) being connected to the flow channel from the free end (263) to the air end (264) of the preceding element.

3. Pump according to claim 2, in which the tubular elements (41-48) are arranged in a star pattern.

4. Pump according to any one of claims 1 to 3, wherein a tubular element (22”) comprises a single flow channel folded back on itself into two parts (27”,28”) forming respectively the two flow channels.

5. Pump according to any one of claims 1 to 3, wherein a tubular element (22') comprises a central tubular portion forming the flow channel (28') for the refrigerant heated from the end free (25') towards the air end (26'), the flow channel of the refrigerant to be heated from the air end (26') towards the free end (25') being formed by the annular part (27') of the tubular element (22') surrounding the central tubular part (28').

6. Pump according to any one of claims 1-5, wherein the free end (25';25") inserted into the ground (21) is tapered.

7. Pump according to any one of claims 1-6, wherein the free end (25',25") inserted into the ground (21) is threaded.

8. Pump according to claim 7, wherein the aerial end (26) of a tubular element (22) is arranged so as to be able to be driven by a screwing member.

9. A method for installing a surface geothermal heat pump according to claim 1, characterized in that, having installed the compressor (5), the condenser (7) and the expansion valve (10), in order to install in the ground (21) the portion of the refrigerant flow circuit, at least one tubular element (22) of said portion of the refrigerant flow circuit is anchored obliquely in the ground (21), by its said free end (25), and its said aerial end (26) is connected to the expansion valve (10) and to the compressor (5).

10. Installation method according to claim 9, wherein, to anchor the tubular element (22) in the ground (21), a hole (23) is first drilled, of a length substantially equal to that of the tubular element (22), and then the tubular element (22) is inserted into the hole (23).

11. Installation method according to any one of claims 9 and 10, wherein the free end (25) of the tubular element (22) is tapered and threaded, and the anchoring of the tubular element (22) is completed by screwing it into the ground (21).

12. An installation method according to any one of claims 9-11, wherein, to install in the ground (21) the portion (40) of the refrigerant fluid flow circuit, a plurality of similar tubular elements (41-48) are anchored obliquely in the ground (21), they are connected together in pairs, the first flow channel at the aerial end (51) of the first tubular element (41) of said plurality (40) is connected to the expansion valve (10), and the second flow channel at the aerial end (81) of the last tubular element (48) is connected to the compressor (5).

13. Installation method according to claim 12, wherein the plurality of tubular elements (41-48) are arranged in a star-shaped bundle.

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