SE505080C2 - Heating systems for collecting heat radiation, preferably from the sun - Google Patents

Abstract

A system for recovering thermal radiation including at least one absorber (10) that receives thermal radiation and a vacuum-generating circulation loop (11). The thermal absorber (10) includes two plane-parallel sheets (101, 102) that are kept at a given distance apart by means of protrusions (103, 104, 105), this distance lying in the range of 0.2-10.0 mm. In this way there is formed between the sheets (101, 102) a gap (106) that extends generally across the whole surface of the sheets. A vacuum is maintained continuously in the gap by means of the vacuum-generating loop (11). The sheets (101, 102) are joined at their edges by means of a sheeting strip (40) having a m-shaped cross section. This sheeting strip permits a certain amount of movement between the sheets (101, 102) at right angles to the respective surfaces of the sheets. The sheeting strip (40) is anchored in a spacing strip (41) which, together with an external frame (42), also functions as a fastening device for a front cover glass (43), which is adapted to permit thermal radiation to pass through, and a rear protective panel (44). The vacuum-generating circulation loop (11) contains a pressure pump (110) for liquid, this pump being connected on its inlet side to a liquid container (116) and on its outlet side to a supply line (112) via a valve (111). The supply line (112) is connected to a vacuum valve (113) that generates a vacuum throughout the entire gap (106) in the thermal absorber (10).

Description

505 oso 2 bulges; and Fig. 3 shows a modification of the system according to Fig. 1.

PREFERRED EMBODIMENT The heating system of Fig. 1 comprises a heat absorber 10 for receiving heat radiation, preferably from the sun, and a vacuum-creating circulation loop11.

The absorber comprises two plane-parallel discs 101, 102, see Fig. 2, which by means of intermediate horizontal, preferably circular bulges 103, 104, 105 are held at some advance certain distance from each other. This distance is in the range 0.01-10.0 mm, and suitably amounts to 1.0 mm. In this way there is a gap 106 between the discs 101, 102 substantially along their entire surface. In this column 106, continuous water is maintained. vacuum by means of the vacuum-creating circulation loop 11. The gap is filled with liquid.

The bulges indicated in Fig. 2 are suitably placed in the corners of imaginary squares with for example. 25 mm side. The height of the bulges will depend on the degree of vacuum desired, which ket in turn determines the boiling point of the liquid.

The discs 101, 102 are joined at their edges in a manner which allows some movement between the lan discs. The merging takes place e.g. by welding or gluing in a dense, flexible bel construction. The discs consist of radiation-absorbing material, e.g. metal. Instructions discs in the discs are designed so that capillarity occurs in the fluid-filled gap between the discs and the adhesion effect between the liquid and the facing surfaces of the discs. IN the liquid film thereby creates a cohesive force, the attractive effect of which is achieved high tensile strength in the liquid. Furthermore, the discs are held together by the continuous kuum which is created in the absorption gap by means of pump pressure. The fluid flow through the gap becomes upward. By means of this design of the construction, the "wet surface" becomes in principle about 100%.

With this embodiment it is achieved that if, at e.g. line breakage, overpressure would occur in gap, the discs can be momentarily displaced from each other (except at the edges), lasting explosion of the structure is prevented.

During the fixed mounting of the discs, these can form an angle in the range 10 - 90, with the horizontal plane, preferably in the range 25 - 45. This gives all the air and possibly formed gas to be evacuated so that no ‘pockets’ are formed, which would impair the absorption tower efficiency ..

The vacuum generating circulation loop 11 includes pressure pump 110 for liquid which is connected on its inlet side to a liquid container 116 and on its outlet side via a first valve 111 to a line 112. This is connected to a vacuum lock 113 at the ab- the upper part of the sorbent 10 for vacuum generation in the space 106 of the heat absorber 10, and to a return line 114, which via a heat exchanger 115 leads back to the liquid container 116.

The pressure pump 110 is further, via a second valve 117, connected to a pressure line 118, which leads to the lower part of the absorbent, and to a pressure balance line 119, which leads to 3 505 080 an open line 120 (atmospheric pressure). A bypass line 121 connects the fluid reservoir- upper part 16 with the open conduit 120.

When liquid from the container 116 is pumped up to the absorber 10, it undergoes an additional batic state change without heat being supplied from the surroundings. At the pressure change gas can be formed which gives rise to a temperature drop in the liquid.

In the absorber, the liquid is affected by an external 'force field', namely by heat radiation. A new movement states occur, according to quantum theory. As liquid flows up into the absorber thermal energy is supplied without raising the temperature to the same extent as in the case of unchanged rat pressure. The absorber assumes the same temperature as the liquid, which results in lower losses. through heat conduction in the construction.

Of the previously mentioned pipe loops, the resin loop 11 (line 112 and line 114) to task to create vacuum, (vacuum loop).

The supply line 118 and the return line 114 form a loop 12 with the task of circulating liquid to the absorber, (heating coil).

Pressure balance line 119 and bypass line 121 form a loop 13 with task to balance variations in atmospheric pressure, as well as to form safety pipes, (by-pass 98) - The vacuum loop (112, 114) and the heating loop (118, 114) appear to have common features. tour guide. In the heating loop there is the vacuum lock 113, which provides the flow through the absorber . When the flow pressure + the hydraulic pressure of the liquid below the atmospheric pressure starts the liquid flow in the gap 106 of the absorber 10. This takes place automatically and independently of variations in atmospheric pressure.

As fluid leaves the absorber 10, adiabatic compression occurs in combination with condensation of ev. gas in the liquid, which gives a temperature increase in the liquid before through the heat exchanger 115.

Overall, the heating system now described provides an increased yield when integrated into for example a solar heating system.

When the heating system is started up and the pressure pump 110 starts working, liquid rises lines 112, 118 and 119. The liquid then flows back through a free fall in the line 114 to the liquid container 116. The flow rate in this line is about 10 times higher than the equilibrium speed (the speed at full operation); the liquid draws air through the vacuum lock 113, and a pressure below atmospheric pressure occurs in the gap 106 in the heat sink. sorbatorn 10. In the line 118 the liquid level rises towards the absorber 10, and in the pressure balance line a 119 to the connection point to the by-pass line 121, from which liquid then flows back to the liquid container 116.

Atmospheric pressure always prevails in the open line 120. As air is evacuated via re- the flow line 114 rises the liquid level in the line 118 up to the absorber 10, as now is under continuous negative pressure. 505 oso 4 When all air has been evacuated, the circulation in the heating coil 118, 114 starts according to the siphon principle. pen. The flow rate is controlled by the level difference between the liquid surface Bit line 118 and liquid surface C in the liquid container 116. Liquid surface A in the pressure balance line 119 is adjusted by adjusting the valve 117.

The vacuum lock 113 basically consists of a line between the absorber 10 and the return line. 114. Its area is about 50% of the area of other pipelines. In the modified system according to Fig. 3, i.a. the change made to the vacuum loop and the heating coil has different return lines; the vacuum loop has a return line 314 going from the exit side of the vacuum lock to the by-pass line 121, and the heating as before, the loop has the return line 114, which now runs from the vacuum lock inlet side of the heat exchanger 115. In this alternative, the vacuum lock 113 has a pipe area of about 10% of the area of other pipes in order for as hot a liquid as possible reach the heat exchanger 115.

With this design, the flow through the heat loop goes smoothly to the heat exchanger 115 without to be cooled by the flow in the vacuum loop. As a result, the inlet temperature becomes the exchanger 115 higher, i.e. approximately the same as the starting temperature from the absorber tower 10, and the flow rate of the vacuum loop is not disturbed by changes in the heating loop flow rate.

The negative pressure in the absorber is selected to some extent depending on the distance between the liquid holder and absorber. An example is a case where the distance is 4m and the pressure 700 millibar; in another case the distance is 10 m and the negative pressure 70 millibar.

The negative pressure can be further regulated by varying the liquid flow in the vacuum loop or the heating loop or possibly in both loops.

Claims (3)

5,505,080 PATENT CLAIMS Heating system for recovering heat radiation, preferably from the sun, comprising heat absorber (10) for receiving the heat radiation and vacuum-creating circulation loop (11), the absorber (10) comprising two plane-parallel discs (101, 102), which by means of intermediate, preferably circular bulges (103, 104, 105) are kept at a certain predetermined distance from each other in the range 0.01 - 10.0 mm so that a gap (106) is present between the discs (101, 102) substantially along their entire surface, in which gap vacuum is continuously maintained by means of the vacuum-creating loop (11), characterized in that said discs (101, 102) are joined at their edges in a manner which allows some movement between the discs, and that the vacuum-creating circulation loop (11) comprises pressure pump (110) for liquid, connected on its inlet side to a liquid container (116) and on its outlet side via a valve (111) to a line (112), connected to a vacuum lock (1 13) for vacuum generation in the entire gap of the heat absorber (10). Heating system according to claim 1, characterized in that the vacuum-creating circulation loop (11) further comprises return line (114) and heat exchanger (115) connected to the liquid container (116), thereby continuously ensuring vacuum in the entire gap of the heat absorber (10) ( 106). Heating system according to claim 1, characterized in that the vacuum-creating circulation loop (11) further comprises return line (314) and bypass line (121) with lower connection to the liquid container (116) and with upper, open end near the absorber (10). ), whereby a vacuum is continuously ensured in the entire gap (106) of the heat absorber (10).