FR2878317A1 - Heat exchange device for e.g. geothermal heating installation, has compressor associated to heat exchanging tubing that comprises winding of superposed coils and defines inner space in which compressor is disposed - Google Patents

Abstract

The device has a compressor (2) associated to a heat exchanging tubing (3) and having an elongated cylindrical form. The tubing is conformed such that it comprises a winding of superposed coils. The tubing defines an inner space, in which the compressor is disposed, opened towards the bottom and towards the top. The winding has end portions holding nozzles for connecting to a water circuit.

Description

The present invention relates to a heat exchange device for a

  geothermal heating installation.

  It is more specifically directed to an installation comprising a first circuit for a refrigerant, equipped with a buried tubular sensor and a compressor, and a second circuit of liquid to be heated, such as water, comprising a heat exchanger.

  In this installation, the refrigerant coming from the sensor arrives at the compressor in the vapor phase, is compressed by the latter in the gas phase, at high pressure and temperature, gives up part of its latent heat to the liquid to be heated which circulates in the exchanger fluid, spring in the high-pressure liquid phase, then returns to the sensor, via an expander, in the gas phase, or mixed liquid-gas, and at low temperature, and the exchanger consists of a pipe through which the liquid to be heated, inside which passes at least one thermally conductive wall conduit carrying the refrigerant from the compressor.

  A primary object of the invention is to provide a device of the aforementioned type which is particularly compact and lightweight, suitable for home use, for example for the production of hot water.

  Another object of the invention, implemented in a preferred embodiment of the invention, is to substantially improve the life of the compressor by controlling the temperature, to prevent overheating of the oil contained. in the compressor, which serves to lubricate the rotating members.

  This overheating, which causes a physico-chemical degradation of the oil, is a traditional cause of premature wear of the compressor and, correlatively, malfunction of the plant in the short or medium term.

  According to a main feature of the invention, on the one hand, said compressor has an elongate shape, approximately cylindrical, with a substantially horizontal axis, or close to the horizontal, and, on the other hand, said tubular shape a vertical axis winding, with superimposed turns, which delimits an interior space open downwards and upwards, the compressor being disposed inside this space.

  This arrangement gives the device a small footprint.

  Moreover, according to a certain number of advantageous, but not limiting, features of the invention: said winding has, seen from above, a substantially rectangular shape, the major axis of which coincides substantially with that of the compressor; - The duct conveying the refrigerant from the compressor through said exchanger pipe is subdivided into a plurality of secondary conduits connected in parallel; said coil-shaped exchanger tubing and said compressor disposed therein are housed within a box.

  According to a preferred embodiment, intended to increase the longevity of the compressor, the latter is separated from the exchanger tubing which surrounds it with a peripheral space, and the device comprises an electric fan capable of generating a flow of air passing through by this peripheral space to lick the compressor housing wall and cool it.

  This flow is preferably, but not necessarily, ascending.

  In this case, particularly advantageously, the compressor housing is provided with a temperature sensor, and the device comprises a device for controlling said fan which is slaved to the temperature measurement made by said probe.

  According to possible additional features: the control device is adapted to actuate the fan when the temperature measured by the temperature sensor exceeds a determined threshold value, and to stop it when this temperature has fallen below this threshold value; ; - The fan is driven by a variable speed electric motor, the control device being adapted to vary its speed proportionally to the temperature measured by the probe; - The exchanger pipe and the compressor disposed inside thereof being housed inside a box, it comprises horizontal lower and upper walls each pierced with an opening allowing the passage of the flow rising air generated by the fan, the latter being positioned on said upper wall.

  Other features and advantages of the invention will appear on reading the following description of a preferred embodiment of the invention. This description is made with reference to the accompanying drawings in which: FIG. 1 is a general schematic view of a geothermal heating installation equipped with a heat exchange device according to the invention; FIG. 2 is an exploded schematic perspective view of the exchanger winding and the compressor; - Figure 3 is a cross-sectional view of the exchanger tubing; - Figure 4 is a top view, in axial section, of the exchanger tubing, the cutting plane being designated IV-IV in Figure 3; - Figures 5 and 6 are simplified views, respectively side and front, of a device according to the invention mounted in a box.

  With reference to FIG. 1, we will now describe a geothermal heating installation to which the device of the invention, designated 1, applies.

  This device is composed of a compressor 2 associated with a heat exchanger 3. The compressor 2 is provided with fixing lugs 20.

  The installation comprises a first circuit 4-5-6 for a refrigerant, equipped with a buried tubular sensor 4, and a second circuit 7 for the liquid to be heated, such as water.

  The sensor 4 is a tubular sensor of known type, in the form of a coil forming a horizontal or approximately horizontal plane, which is buried outside a dwelling, generally in a part of garden J, at a depth of the order of 0.6 to 0.7 m.

  It consists for example of a polyethylene tube, or copper coated in a polyethylene sheath. As an indication, its length may be of the order of 60 to 80 m and its inner diameter of between 8 and 10 mm.

  The refrigerant is for example a HFC (Hydro-Fluoro-Carbon).

  The device 1 is located inside the house.

  The tubular sensor 4 is connected by a portion 5, said return to the inlet 21 of the compressor 2 and a portion 6, said departure to the outlet 22 of the latter.

  As will be seen below, the exchanger 3 is a tubular wound on itself on a few turns (three or four), inside which passes the water to be heated. For this purpose, the second circuit 7 comprises an inlet pipe 70 connected to one end 700 of the exchanger, and an outlet pipe 71 connected to its opposite end 710.

  The cold water EF arrives through the pipe 70, for example from the drinking water distribution network.

  The hot water EC exits through the pipe 71, via a circulator 72, for any use, for example to supply a hot water tank or a radiator.

  Part 6 of the first circuit, carrying the refrigerant, also passes through the exchanger pipe 3.

  The portion of the portion 6 that passes through this tubing has a thermally good conducting wall, for example copper (sheathed).

  In the illustrated embodiment, this portion is in fact made up of three elementary ducts 63, 65, 66, connected in parallel; the sum of the areas of their section is equal to the area of the section of the duct 6, so as not to disturb the flow rate of the refrigerant in said portion. This subdivision makes it possible to increase the contact area between the wall of the ducts in which the refrigerant circulates and the water that surrounds them, which favors heat exchange.

  Preferably, as illustrated in FIG. 4, the three elementary ducts 63, 65, 66 are helically wound and interlaced, also in order to improve the quality of the heat exchange.

  Such an arrangement is known per se.

  The compressor 2 is electrically driven, by means of an integrated electric motor; 23 denotes its connection terminals to a source of electrical current 10, via cables 11, 12 (represented by dashed lines) and a suitable control circuit 13.

  In this installation, the refrigerant coming from the sensor 4 goes into the return circuit part 5, where its direction of movement is symbolized by the arrows a, and arrives at the compressor 2 in the vapor phase.

  In the compressor, it is strongly compressed, so that it is heated to a relatively high temperature, as an indication of the order of 80 C.

  This superheated steam leaves the compressor (arrows b) and enters the exchanger pipe 3, which it passes from one end to the other, inside the elementary ducts 63, 64, 65. path, there is a heat exchange with the water that flows in the opposite direction in the pipe 3, which causes the condensation of steam, which gives part of its latent heat to the water, the condensation being an exothermic phenomenon.

  It is therefore hot water EC that leaves the pipe 3 through the pipe 71.

  As an indication, the circulation of the water inside the exchanger causes each of its passages to increase its temperature of the order of 3 to 4 C.

  The refrigerant leaving the exchanger is, in turn, in the liquid phase at high pressure.

  It returns to the sensor 4 (arrows c) after passing successively, in a known way, a dehydrating filter 60, a heat exchanger 61 and a pressure reducer 62.

  The heat exchanger 61 carries out a heat exchange between the return and flow parts 6 so as to ensure the evaporation of any remaining liquid pockets in the refrigerant which is directed towards the compressor, ensuring that this fluid is entirely in the vapor phase. It also improves the efficiency of the installation, by recovering some of the residual heat that returns to the sensor.

  The expander 62 lowers the fluid pressure so that it is a cold, low pressure liquid-gas mixture that reaches the sensor.

  During its journey in the buried sensor 4, the refrigerant recovers heat from the ground, and is gradually heated and completely vaporized, so that it comes out of the heated vapor phase.

  As illustrated in FIG. 2, in accordance with the invention: on the one hand, the compressor 2 used is of elongate, approximately cylindrical shape, of axis X-X 'close to the horizontal (so-called compressed compressor); - On the other hand, the exchanger pipe 3 is shaped such that it comprises a winding of a few superimposed turns 30, of vertical axis ZZ '.

  Seen from above, the winding has a substantially rectangular shape, with rounded corners, in a quarter circle (see Figure 1); its end portions 31, 32 carry the ends 700, 710 for connection to the water circuit 7.

  Figures 3 and 4 show the internal structure of the tubing 3. It has a circular section. It comprises a tube 33, for example copper, surrounded by a flexible sleeve 34 of insulating material, to prevent heat loss out of this exchanger. These figures also show the arrangement of the helical elementary ducts 63, 64 and 65 of the refrigerant circuit.

  The water to be heated passes inside the tube 33, surrounding these ducts.

  As an indication, the external dimensions of the rectangle formed by the winding are of the order of 300 x 400 mm.

  The sheath 3 has an outside diameter of 60 mm.

  The tube 33 has an outside diameter of 22 mm and an inside diameter of 20 mm. The elementary ducts 63, 64 and 65 have an outside diameter of 6 10 mm and an inside diameter of 4.5 mm.

  The compressor used is, for example, the hermetic compressor model marketed by TECUMSEH EUROPE under the trade name L'UNITE HERMETIQUE (trade mark) and bearing the reference HGA4476Y. This model has an overall length of 283 mm, an overall height of about 184 mm, and has a cylindrical housing body of about 122 mm.

  According to an essential characteristic of the invention, this recumbent compressor 2 is housed inside the winding 3, approximately halfway up it. Its X-X 'axis is in the plane corresponding to the long axis of the winding rectangle (see Figure 1).

  In practice, the X-X 'axis may be slightly inclined relative to the horizontal (see Figure 5).

  The device consisting of the compressor 2 and the exchanger 3 is mounted inside a box 8, visible in FIGS. 5 and 6. It is a box that has the shape of a rectangular parallelepiped (or square), comprising a metal frame 80 covered with a cowling; this is composed of upper and lower (horizontal) plate walls 81, 82 respectively, and peripheral (vertical) side plates 83.

  The plates 81 and 82 are pierced with a circular central opening 801, respectively 802, which advantageously has a small flange forming a cuff facing outwardly of the box. These openings are centered on the vertical axis Z-Z 'of the exchanger winding 3.

  The compressor is fixed inside the box in a centered position, at mid height thereof. This attachment is provided by appropriate mounting members, such as rods 85 connected to the frame of the box and on which are fixed the fastening lugs 20 of the compressor.

  Appropriate fastening and centering means, not shown, adequately hold the winding 3 in the box around the compressor 2, this with a certain spacing, which provides a peripheral space around the compressor and inside the winding.

  The casing 8 has support feet 84 by which it rests, in the example illustrated, on a bracket C at right angles, fixed to the wall M of a house by screws V. In one possible variant, the casing is provided with appropriate fasteners for direct attachment to the wall.

  On the top of the box 8 is mounted an electric fan 9, supported by appropriate fastening tabs 91, whose blades 90 overhang the opening 801 of the plate 81.

  The fan 9 is supplied with electric current from the aforementioned source 10 via a control circuit 101. It is preferably a variable speed fan whose value is defined by the control circuit.

  When it is running, it generates an upward flow of air, taken under the casing, penetrating inside the casing through the lower opening 802 (arrows F, FIG. 6), passing into the peripheral space at the end of the chamber. inside the winding 3 around the compressor 2, by licking the wall, and finally emerging upwards through the upper opening 801 (arrows G, Figure 6).

  In operation, the compressor is normally heated to a relatively high temperature which, as an indication can reach a value of the order of 70 to 80 C at the wall of its housing.

  The oil hermetically contained in this casing, which ensures the lubrication of moving parts, is therefore subjected to a high temperature, detrimental to the preservation of its physicochemical qualities.

  With the use of the fan 9, this temperature can be maintained at a substantially lower level, for example in a range between 30 and 45 C, because the air flow that licks the compressor is at a temperature ambient and therefore cools it.

  According to a particularly advantageous characteristic of the invention, the operation of the fan is slaved to the effective temperature of the compressor.

  In the illustrated embodiment, a temperature sensor 100 is fixed on the wall of the housing 2, preferably in its lower part (vis-à-vis the oil bath).

  This probe 100 is adapted to provide the control circuit 101 with an electrical signal representative of the measured temperature value.

  The circuit 101 is programmed to start the fan motor when the measured temperature exceeds a certain predetermined threshold value, for example equal to 40 C, and to regulate the speed of rotation - and, correspondingly the flow rate of the flow cooling air - so that this value remains constantly within a given range, for example between 30 and 45 C.

  In practice, most of the components of the installation that are inside the house, such as the electrical control devices 13 and 101, the dehydrator 60, the exchanger 61 and the expander 62 are also advantageously mounted in the box 8, the various control, adjustment and control devices useful for the proper functioning of the installation can be grouped on the front of said box, so as to be easily accessible to users.

  Such a box is compact, relatively light, and autonomous.

  It can be easily transported, handled and installed in a room, for example against a wall near a hot water tank.

  The air flow which ensures the cooling of the compressor is naturally heated by it; as this air circulates in a loop, it ensures a certain heating of the room or, at the very least, participates in its heating.

Claims (9)

  1. Heat exchange device for a geothermal heating installation, said installation comprising a first circuit for a refrigerant, equipped with a buried tubular sensor (4) and a compressor (2), and a second circuit liquid to be heated, such as water, comprising a heat exchanger (3), installation in which the refrigerant from the sensor (4) arrives at the compressor (2) in the vapor phase, is compressed by the latter in phase gas, at high pressure and temperature, gives up part of its latent heat to the liquid to be heated flowing in said exchanger (3), spring in the high pressure liquid phase, then returns to the sensor (4), via a pressure reducer (62) in the gaseous or mixed liquid-gas phase, and at low temperature, said exchanger (3) consisting of a tube through which the liquid to be heated passes, inside which passes at least one duct (63, 64, 65) to thermally conductive wall ice carrying the refrigerant from the compressor (2), characterized in that, on the one hand, said compressor (2) has an elongate, approximately cylindrical shape, of substantially horizontal axis (X-X '), or a neighbor from the horizontal, and that, on the other hand, said tubing (3) has the form of a winding of vertical axis (Z-Z '), with superposed turns, which delimits an interior space which is open towards the bottom and upwards, the compressor (2) being disposed within this space.   2. Device according to claim 1, characterized in that said winding has, seen from above, a substantially rectangular shape, the major axis coincides substantially with that (X-X ') of the compressor (2).   3. Device according to claim 1 or 2, characterized in that the duct (6) conveying the refrigerant from the compressor (2) through said exchanger pipe (3) is subdivided into a plurality of secondary ducts (63, 64 , 65) connected in parallel.   4. Device according to one of claims 1 to 3, characterized in that said exchanger pipe (3) having the shape of a winding and said compressor (2) disposed inside thereof are housed inside a box (8).   5. Device according to one of claims 1 to 3, characterized in that said compressor (2) is separated from the exchanger tubing (3) which surrounds it by a peripheral space, and that the device comprises a fan electrical device (9) adapted to generate an air flow, preferably upward, passing through this peripheral space to lick the compressor housing wall (2) and cool it.   6. Device according to one of claims 1 to 3, characterized in that the housing of said compressor (2) is provided with a temperature sensor (100) and the device comprises a device 101) for controlling said fan ( 9) which is slaved to the temperature measurement made by said probe (100).   7. Device according to claim 6, characterized in that said control device is adapted to actuate said fan (9) when the temperature measured by the temperature sensor (100) exceeds a predetermined threshold value, and to stop it when this temperature has fallen below this threshold value.   8. Device according to claim 7, characterized in that said fan (9) is driven by a variable speed electric motor, said control device (101) being adapted to vary its speed proportionally to the temperature measured by the probe (100).   9. Device according to one of claims 5 to 8, wherein the exchanger pipe (3) and the compressor (2) disposed inside thereof are housed inside a box (8). ), characterized in that this box comprises lower walls (82) and upper (81) horizontal pierced with an opening (802; 801) allowing the passage of the upward flow of air generated by the fan (9), this last being positioned on said upper wall (81).