Cooling device

Abstract

A device for realizing a cooling effect in a space comprises: a housing with a heat-conducting wall, which housing bounds a chamber through which air can flow; an air inlet which connects to the chamber and to said place, —an air outlet connecting to the chamber; air transport means for transporting air from the air inlet via the chamber to the air outlet; and moistening means for moistening the inner surface of the wall; this such that air supplied by the air transport means is introduced into the chamber via the air inlet, passes along the moistened inner surface of the wall in the chamber and is discharged from the chamber via the air outlet, whereby the water present on the inner surface of the heat-conducting wall evaporates and is entrained by the air flowing by, and the wall is cooled.

Claims

1. A device for realizing a cooling effect in a space, wherein the space may be an accommodation area, an office space, a living room or a cab in a means of transport, comprising: a housing with a heat-conducting wall, which housing bounds a chamber through which air can flow, wherein the heat-conducting wall is facing the space such that the space is cooled by radiation absorption; an air inlet which connects the space to the chamber and through which only air from the space travels into the chamber, wherein the air entering the chamber is untreated air from the space; an air outlet connecting to the chamber through which air exits from the chamber; air transport means for transporting air from the space through the air inlet via the chamber to the air outlet; and moistening means for moistening an inner surface of said wall with an evaporable liquid; such that all of the air from the space transported by the air transport means is introduced into the chamber via the air inlet, passes along the moistened inner surface of said wall in the chamber and is discharged from the chamber via the air outlet, whereby evaporable liquid present on the moistened inner surface evaporates and is entrained by the air flowing by, and said wall is cooled, but to a temperature never less than the dew point of the air in the space, the heat-conducting wall performing both functions of bounding the chamber and cooling the space by radiation absorption.

2. The device as claimed in claim 1, wherein the air outlet debouches outside the space for cooling.

3. The device as claimed in claim 1, wherein the wall is disposed horizontally.

4. The device as claimed in claim 1, wherein the housing is embodied as a hollow panel with a linear dimension transversely of the wall amounting to a maximum of 1/10 of a representative linear dimension.

5. The device as claimed in claim 4, wherein the linear dimension is selected from the group comprising a length and a width of said wall.

6. The device as claimed in claim 1, wherein said inner surface is embodied such that water disperses thereover without droplet formation.

7. The device as claimed in claim 6, wherein said inner surface is subjected beforehand to a corona treatment.

8. The device as claimed in claim 6, wherein said inner surface is provided with a hydrophilic cover layer.

9. The device as claimed in claim 6, wherein said inner surface is provided with a porous cover layer.

10. The device as claimed in claim 9, wherein the porous cover layer is selected from the group comprising cement and a fibrous mat.

11. The device as claimed in claim 1, wherein the moistening means comprise a number of drippers or sprayers.

12. The device as claimed in claim 1, wherein means enlarging the heat-conducting surface area are added at least to the inner side and at least to a part of the heat-conducting wall, said surface area-enlarging means being in direct thermal contact with the wall.

13. The device as claimed in claim 12, wherein means enlarging the heat conducting surface area are fins.

14. The device as claimed in claim 1, wherein the surface area-enlarging means are added to the inner surface of the wall.

15. The device as claimed in claim 1, wherein the moistening means are only active in an upstream zone of the wall such that the air cooled in this zone cools a remaining downstream zone of the wall.

16. The device as claimed in claim 1, wherein the air transport means is a fan means.

17. The device as claimed in claim 1, wherein the evaporable liquid is water.

18. The device as claimed in claim 1, wherein the means of transport is one from the group comprised of a car, a boat, and an aircraft.

19. The device as claimed in claim 1, wherein the housing is embodied as a hollow panel with a linear dimension transversely of the wall amounting to a maximum of 1/20 of a representative linear dimension.

20. The device as claimed in claim 1, wherein the housing is embodied as a hollow panel with a linear dimension transversely of the wall amounting to a maximum of between 1/30 to 1/50 of a representative linear dimension.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will now be elucidated with reference to the accompanying drawings of two random exemplary embodiments.

(2) In the drawings:

(3) FIG. 1 shows a partially cut-away perspective view of the bodywork of a car provided with a cooling device with electric fans;

(4) FIG. 2 shows a view corresponding to FIG. 1 of an embodiment which operates without electric fans but is based solely on an airflow which occurs during driving of the car;

(5) FIG. 3 shows a view corresponding to FIGS. 1 and 2 of an embodiment which can operate on the basis of electric fans as well as on passing wind;

(6) FIG. 4 shows a view corresponding to FIGS. 1, 2 and 3, wherein a liquid-retaining layer with the associated moistening means is present only on the upstream side of the lower wall;

(7) FIG. 5 shows a view corresponding to FIGS. 1-4 of an embodiment with a moisture-retaining layer with associated moistening means arranged only upstream, and provided downstream with surface area-enlarging means, in particular fins;

(8) FIG. 6 shows a view corresponding to FIGS. 1-5 of an embodiment with provisions for the use of precipitation water;

(9) FIG. 7 is a partially cut-away perspective view from the underside of a device according to the invention in the form of a ceiling panel for use in a room or similar space;

(10) FIG. 8 is a partially cut-away perspective view from the top side of the device according to FIG. 7;

(11) FIG. 9 shows a plastic channel plate greatly resembling for instance corrugated cardboard;

(12) FIG. 10 shows a metal plate on which is arranged a plate with more or less U-shaped channels;

(13) FIG. 11 shows a cooler according to the invention which is laid on a tabletop and provided with a water reservoir and fan; and

(14) FIG. 12 is a partially cut-away view of cooler which can be used on a tabletop and is provided with a small axial fan and a droplet reservoir.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(15) FIG. 1 shows the body 1 of a car with a cooling device 2 according to the invention. The cooling device is embodied as a shallow panel with an inner space 10 and is bounded on the top side by car roof 3 and on the underside by a horizontal wall 4 which, compared to usual cars, takes the place of the so-called roof lining. The inner surface of lower wall 4 is provided with a liquid-retaining layer 5, consisting for instance of Portland cement or a thin layer of fibre material. The layer thicknesses can for instance be in the order of 0.1-0.3 mm. A suitable, easily evaporating liquid, for instance water, is fed to layer 5 by an arrangement of sprayers 6 which provide for a uniform moistening of layer 5. The sprayers receive water via a conduit system (not shown) connected to a conduit 24 and a supply tank 22 with a filler cap 28. Water can be fed under pressure intermittently, in accordance with requirement, to sprayers 6 by means of a simple pump 23, for instance a pump of the type used to deliver windscreen washer fluid.

(16) Arranged at a suitable location are fans 7 which blow air, indicated with arrows 8, drawn only from the space 9A inside the cab of the car through air inlet 8A and through the hollow jambs 9 into chamber 10 such that the inblown air 8 flows over the moistened layer 5 and leaves device 2 at the rear through hollow jambs 9 as according to arrows 11, and may be discharged through the air outlet 11A back into the space 9A or to the surrounding environment. The air entering the chamber (10) is untreated air from the space (9A). As a result of a flow of non-saturated air flowing over the wet layer 5 the water present in this layer 5 evaporates, this having in a known manner a strong cooling effect. Wall 4 is hereby cooled. The wall 4 is facing the space 9A, such that the space 9A is subjected to radiation from the wall 4.

(17) A wall is thus placed in the vicinity of the head of the users which has a lower temperature than the air toward which it is directed, thereby creating a net radiation absorbing effect, moreover in the vicinity of the head, relatively the greatest radiator and certainly the most sensitive in respect of perception of cold and heat. In the shown embodiment the process air is discharged to the outside. The reason for this is that the space in the cab of a car is so limited that the air humidity can increase quickly here due to the water evaporated because of the cooling, and this can be unpleasant.

(18) Fans 7 are placed as overpressure fans, therefore on the upstream side of device 2. Alternatively, fans 7 could also be placed as underpressure or suction fans, and could therefore be disposed on the downstream side of device 2.

(19) FIG. 2 shows a variant in which the intake airflow 8 is not generated by fan means as in FIG. 1, but via favourably placed outflow openings to the outside world 125 and 126 placed at a location in the outer side of the car where underpressure or a very high air speed prevails during driving, whereby the outflowing air 11 is suctioned away and airflow 8 is thereby drawn into chamber 10. Situated on the rear side of chamber 10 are outlet openings 113 which can be opened and closed by means of flaps 125 operated by actuators 126. The cooling device according to FIG. 2 will only function in the case of a substantial vehicle speed.

(20) FIG. 3 shows an embodiment wherein use is made of both fans 7 and outflow openings 113. The small fan in the middle jamb is omitted, while the airflow from the fan arranged on the front side of the vehicle nevertheless provides for airflow at that location. Fans 7 could otherwise be accommodated directly in lower wall 4.

(21) FIG. 4 shows an embodiment wherein the heat-conducting lower wall is provided with a water-dispersing and/or water-retaining layer, for instance a thin layer of Portland cement, over about half its length in the flow direction of the air from the intake side. The sprayers 6 are placed only in this zone. In the embodiment according to FIGS. 1, 2 and 3 these are placed distributed in a regular arrangement over the whole surface. The second half of the lower wall, warmer than the first half, can then reheat the throughfed, moistened and, in ideal conditions, cooled air, whereby the temperature of the second half of the lower plate decreases while the solubility of water vapour increases due to the raised air temperature, thereby decreasing the danger of condensation in chamber 10.

(22) FIG. 5 shows a variant of the embodiment according to FIG. 4, wherein surface area-enlarging means 14 are arranged on the downstream side on the heat-conducting lower wall. Such fins can for instance be manufactured from a heat-conductive material such as copper or aluminium.

(23) FIG. 6 shows an embodiment wherein precipitation, in particular rainwater, is collected via a receptacle 29 which drains into a reservoir 22, which can moreover be provided with a filler cap, via a conduit 30 and via roof gutter 31 via a conduit 30 into for instance a second reservoir 22 which is also provided with a filler cap 28 with a pump 23 and a conduit 24 connecting to the conduit system (not shown) and sprayers 6, wherein connecting conduit 32 supplies the water from roof gutter 31 on the other side.

(24) The device according to FIG. 3 in a car can thus operate without external energy supply, or optionally with very low energy consumption, i.e. the optional consumption of fan means 7. This creates additional possibilities: suppose that the car is parked in the sun and the roof were provided with photovoltaic panels. Such panels built into a roof of a car are for instance known from the German car manufacturer Audi. Audi supplies as option a sunroof which, with a sufficient irradiation by sunlight, powers an electric fan which ventilates the interior during parking, whereby the temperature in the interior increases less extremely than in the case of a non-ventilated cab. Such a known system does not in fact cool, it merely ventilates. If the electrical energy from the solar panel is now used in the configuration according to FIG. 1 in combination with device 2, a cooling effect is realized with a fraction of the energy required for sluice ventilation. Cooling takes place at the position where it has the most effect, i.e. on the top side where, after people have got in, their heads are situated, so that these people feel the comfortable effect of radiation absorption.

(25) It is noted that it is deemed useful in this application to insulate the inner surface of roof 3 of chamber 10, for instance by means of a layer of expanded polystyrene foam. This prevents the cooling effect resulting from the operation of the cooling device being partially counteracted by too strong a heating under the influence of solar irradiation.

(26) FIGS. 7 and 8 show a panel-like cooling device 15 according to the invention intended for instance for hanging on a ceiling of for recessed placing therein. Where applicable and useful, the same reference numerals are used in FIGS. 7 and 8 as in FIG. 1.

(27) Instead of a fan placed at distance, device 15 comprises two tangential fans 16 which have a small diameter and have a length amounting to about half the width of device 15. For purposes of mechanical rigidity the device has two compartments separated from each other by a vertical dividing wall 17. In the context of the invention this principle is more generally applicable in respect of the use of modularity.

(28) On the blow-out side the upper wall 18 has two outlet slits 19 which debouch into respective plenum compartments 20 which discharge the cooled moistened air 11 via an outlet opening 21, which debouches outside the user space for instance via a conduit. In an alternative embodiment (not shown) fans 16 could also be placed on the outlet side and air drawn in via plenum compartments 20.

(29) In a further alternative embodiment (not shown) the plenum compartments could be omitted, since the air which is moistened by evaporation of water and which has flowed through chamber 10 will under normal conditions have little effect on the relative air humidity in buildings.

(30) This device could also be connected to the ventilation device or venting of a building or an optionally present solar chimney, wherein the whole extraction can take place completely passively on the basis of a thermosiphoning effect.

(31) FIG. 9 shows a so-called channel plate 39, a panel constructed from two plates with mutually parallel ribs therebetween, which displays a great similarity to corrugated cardboard and could be used as housing for the cooler in a similar manner as the housing of the cooler according to FIG. 7 and FIG. 8.

(32) Where applicable and useful, the same reference numerals are used in FIGS. 9, 10, 11 and 12 as in FIGS. 1-9.

(33) The lower plate 4 in the figure is provided on the side directed toward the inner side of the panel with a moisture-retaining layer 5. The second plate of the channel plate forms the wall 18. The intermediate ribs can be compared to the dividing wall 17. Channel plates can for instance be obtained embodied in polymethyl methacrylate (PMMA), polycarbonate (PC) and polypropylene (PP). This latter embodiment is mainly very thin-walled. Usual embodiments weigh 300-500 gram per square meter at a panel thickness of 3-5 mm.

(34) FIG. 10 shows a variant of the channel plate according to FIG. 9. Lower plate 4 is now for instance a metal plate on which a second metal plate 40 is arranged with more or less U-shaped channels. A moisture-retaining layer 5 is arranged in the channels on the side of extended surface 4 directed toward second plate 40.

(35) The moisture-retaining layer 5 is moistened by first carrying the cooling medium, for instance water, as according to arrows 41 through the U-shaped channels and discharging it as according to arrows 42. Air from the user space is then carried through the U-shaped channels as according to arrows 41 and discharged as according to arrows 42.

(36) FIG. 11 shows a cooler similar to that of FIGS. 8 and 9 which is laid on a tabletop 44.

(37) In contrast to the ceiling plate of FIGS. 8 and 9, plate 4 now faces upward. Coolant, for instance water, is fed intermittently from water reservoir 43 to the channels of channel plate 39 as according to FIG. 9 in order to moisten the moisture-retaining layer 5 (not shown). The tangential fan 16 carries air through the channels of channel plate 39 so that plate 4 cools due to the extraction of heat of evaporation due to evaporation of the coolant.

(38) FIG. 12 shows a partly cut-away view of a cooler similar to that of FIG. 11, wherein an axial fan 48 blows air through channel plate 39 via a plenum compartment 47. Plate 4 once again faces upward here.

(39) Coolant, for instance water, drips via suitably dimensioned holes out of reservoir 45 into the channels of channel plate 39 for the purpose of moistening the moisture-retaining layer 5 not shown in the drawing. Possible excess coolant is collected in reservoir 46. The coolant can be pumped back from reservoir 46 to reservoir 45 or flow back by means of capillary action to reservoir 45. It is also possible to envisage the excess coolant being poured back manually into reservoir 45.

(40) This cooler could in this embodiment also be laid on a tabletop. A ceiling plate is once again created if channel plate 39 is rotated through 180° over the longitudinal axis of the channels.

(41) For the drawn embodiment of FIGS. 1 to 6 for applying in for instance vehicles, FIGS. 7 and 8 as ceiling plate and 9 to 12 as cooler in very thin form as both ceiling cooler and for instance tabletop cooler, it is the case that a transparent cooler can be made by making use of for instance glass, PMMA and PC as material for the plates of the chamber which are important for operation and through which air is carried and on which according to 5 a moisture-retaining layer which is transparent, such as for instance a transparent, hygroscopic polymer, is arranged on the relevant sides.

(42) Another means for reducing the surface tension of the coolant, for instance water, could also be used instead of a moisture-retaining layer 5. It is possible here to envisage a slowly self-sacrificing layer of a soap-like substance, a surface treatment such as a corona treatment or surface roughening.

(43) These alternatives to the moisture-retaining layer can also be wholly transparent, certainly when they are moistened to some extent.

(44) The coolant, for instance water, being visible could moreover have a placebo effect on the people in the user space.