EMISSION-FREE COOLING SYSTEM

RELATED APPLICATION

This application claims priority and benefit from Swedish patent application No. 0801406- 0, filed July 16, 2008, the entire teachings of which are incorporated herein by reference. TECHNICAL FIELD

The present invention relates to an installation or a system having primarily the purpose to deliver cooling and working without emissions.

BACKGROUND OF THE INVENTION

A chemical heat pump is disclosed in the published International Patent Application WO 00/37864, the chemical heat pump working according to a particular process, herein called the hybrid principle, the hybrid method or the hybrid process.

Normally a great number of valves and pumps are needed in a chemical heat pump to perform said process. In a heat pump typically about twenty valves and at least three circulation pumps are provided. The cost of such valves is about SEK 20.000 and for the operation thereof and of the pumps an electric power of about 0.5 kW is required.

SUMMARY

It is an object of the invention to provide a system for cooling, such as for cooling indoor air, e.g. in a building, typically a private home or an office.

In the system all flows that are needed to operate a cooling installation and to distribute the power to the place where it is used are controlled. The flows are produced by self-circulation, i.e. by the effect of gravitation and differences in density between portions of a liquid that are warmer than other portions of the liquid.

There are no moving parts in the system and no control system and the system does not require any supply of electricity. The automatic control of the system and the automatic transport of liquid can be used in any cooling installation. In particular, the system can be used in a solar- powered cooling installation but other sources of heat are also conceivable.

Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the methods, processes, instrumentalities and combinations particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

While the novel features of the invention are set forth with particularly in the appended claims, a complete understanding of the invention, both as to organization and content, and of

the above and other features thereof may be gained from and the invention will be better appreciated from a consideration of the following detailed description of non-limiting embodiments presented hereinbelow with reference to the accompanying drawings, in which:

- Fig. 1 is a schematic view of an installation or a system for cooling e.g. a building, showing how the system is working during daytime,

- Fig. 2 corresponds to Fig. 1 but shows the operation of the system in the night,

- Fig. 3 corresponds to Fig. 1 but shows the operation of the system when cooling is to be distributed,

- Figs. 4 and 5 are schematic but somewhat more detailed views of an installation working in the same way as the installation or system of Figs. 1 - 3,

- Fig. 6a is a schematic view of a unit pipe or a unit cell having external heat exchange surfaces, and

- Fig. 6b is view similar to Fig. 6b of an alternative design of a unit pipe.

DETAILED DESCRIPTION A system based on the use of unit cells or unit pipes will now be described. Such unit cells are complete chemical heat pumps. A unit cell is charged by keeping one end of the cell, herein called the second end, warmer than the opposite end, here called the first end. Thereafter, when for example no particular external temperature is applied to its two ends, the heat pump generates cooling in the end, which earlier was less warm, and heat in the end, which earlier was kept warm. Such a unit cell is suited to be used for example with solar heating, by placing the second end thereof e.g. in a solar energy collector in order to deliver cooling during the dark hours of the day.

One of several possible designs of a unit cell or a unit pipe is disclosed in the published International Patent Application WO 2007/139476. The unit cell according to this International Patent Application typically includes an elongated, inner closed chamber, which usually is the space inside a totally sealed pipe or tube 21, see Fig. 6a. Both the reactor 22 and the condenser/

evaporator 23 of the chemical heat pump are housed in the elongated chamber. In the reactor that is located at a second end of the chamber an active substance is provided, which is carried by a matrix 24 applied to the wall of the chamber at this end and which can absorb the vapour phase of a volatile liquid. At the opposite, first end of the chamber the condenser/evaporator 23 is lo- cated, in which the volatile liquid, the sorbate, is condensed and evaporated and which can be separated from the other end by a partition 25. The partition can be designed as an inner pipe and then a gas channel, in which the vapour phase is transported, passes inside the inner pipe to the second end of the chamber. Thus, the condenser/evaporator 23 is constituted by the space 27 between the gas channel and the surfaces of the walls in the first end of the chamber, and vapour can be condensed and collected in and evaporated from this space. The unit pipe can be manufactured from glass or enameled steel to be totally sealed. The unit pipe 21 can also have matrix substance 28 in its condenser/evaporator part 23 and then this matrix substance can be located at the upper portion of the inner surface of the pipe, inside the space 27, so that a channel 29 is formed between the outer surface of the tubular part of the partition 25 and the inner surface of the matrix, allowing transport of condensate and vapour to all portions of the matrix, see Fig. 7b. In Figs. 1 - 3 a system for heating and/or cooling an object such as a building H is shown, the object generally called a user. The system includes an upper container B and a lower container Kvf. These containers contain in their inner spaces quantities Ll, L2 of a suitable liquid such as water. Liquid can be made to automatically move upwards to the upper container when such functionality is required and liquid can be made to automatically move downwards from the upper container, when such functionality is required. It is controlled and operated without moving parts, without any control system as in commonly used heating/cooling systems and without a need to consume electric power. All energy for operating the system is taken from an outer heat source, for example from the heat of the sun, and from the unwanted heat in the house or the user H.

The state when charging the system that can take place during daytime, i.e. during the light parts of the day, is shown in Fig. 1. The function of the system in the charging state is as follows:

A device designed as a heat pump unit R of the unit cell kind, such as a unit pipe of the type described above, has its first part Tl located in the liquid Ll in the upper container B, mainly in the upper part of the inner space in this container. The upper container is at least partly thermally insulated by insulation indicated at II . The free second end T2 of the unit pipe is arranged so that it at times will be heated, and, in the case of using solar energy, it can be sunlit during daytime. Thereby, the heat in the second part T2 of the unit pipe R will diffuse to the first part Tl of the unit pipe located inside the liquid-filled upper container B. Hence, the unit pipe R

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is charged, such as by volatile liquid being transferred from the accumulator part thereof to the condenser/evaporator part thereof. In order that it will work and that the unit pipe R will be capable of taking care of and transform the heat to an energy storage, the first part Tl of the unit pipe must be kept considerably colder than the second part T2. This necessary cooling is auto- matically achieved by the fact that the liquid Ll in the upper container B, in particular close to the unit pipe R, becomes heated. Then the heated liquid will ascend, as shown by the arrow 1, because of the difference in weight due to the fact that the density of the heated quantity of liquid is lower than the density of the colder parts of the liquid, towards a cooling source, also called a heat sink, such as a cooling flange Kf mounted to the uninsulated, upper part of the upper con- tainer B. At the cooling flange Kf the ascending liquid is cooled by the fact that the cooling flange transfers the considerably lower temperature of the surrounding colder air to the ascending liquid, whereby it becomes heavier and thereafter moves downward, as shown by the arrow 3, and again is cooling the first part Tl of the unit pipe R.

The upper container B should be located so that layered differences in liquid temperature are actually obtained, and a condition for this to work can be that it all the time is in a state of rest, without any forced stirring, and that it for example is not exposed to too strong vibrations.

This circular flow in the upper container B continues as long as the second end T2 of the unit pipe R is being heated, i.e. in the special case, when the sun is shining on the unit pipe, and the cooling flange Kf at the same time has a temperature lower than that of the liquid Ll in the upper container close to the first end Tl of unit pipe. All this time the heat pump in the unit pipe R is also charged.

The state when discharging the system, which according to the discussion above can take place in the night, i.e. during the dark part of the day, is shown in Fig. 2. The function of the system in the discharging state is as follows: After the heating of the second end T2 of the unit pipe R has ended, i.e. in the special case after sunset and when the temperature of the surrounding air decreases, the temperature of the unit pipe R in the second part T2 of the pipe located outside the upper container B will decrease, in the special case both due to the decrease of the temperature of the ambient air and because thermal energy is emitted by radiation from the outer surface of the unit pipe towards the sky. This means that the temperature of the unit pipe R in the first part Tl, which is introduced in the upper container B, will decrease still more, since the charging that has taken place during the previous day will result in a state of equilibrium in which the inner part of the unit pipe at the first end Tl thereof that is introduced in the liquid Ll tends to be considerably colder than the second part of the unit pipe at the end T2 thereof that is located outside the upper container B,

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such as about 30° C colder in a typical design of the unit pipe according the above mentioned

International Patent Application.

Thereafter, when the first part Tl of the unit pipe R introduced in the liquid Ll is cooled due to the discharging performed by the heat pump function of the unit pipe, the liquid in the upper container B around the unit pipe R will be cooled and by this fact, due to the difference in density and to gravitation, be transported downwards, in the direction of the arrow 5, to the inner space filled with the liquid L2 in the lower container Kvf. Then, the cold liquid will pass downwards from the bottom of the inner space of the upper container B through one or more pipes 7 extending from the bottom of the upper container to the inner space of the second container Kvf. The pipes 7 can for example be substantially straight and have a substantially vertical course as shown. Generally, the pipe or pipes must be located so that liquid can be transported, only by the effect of gravitation, from its/their upper end/ends to its/their lower end/ends. It means that no S-formed bend of the type found in water traps can be allowed in the pipe/pipes. It can also be said in the way that when one moves along the pipe from the upper end thereof the movement shall all the time be in the same direction, i.e. downwards, and thus there must not be any part of the pipe, where one, in such a movement, changes one's direction and instead would move upwards, towards a position located at a higher vertical level. It also applies to the pipes that will be described below.

The lower container Kvf can be thermally insulated using a thermally insulating, enclosing cover indicated at 12, for example at all its outer surfaces as shown.

In the same time as cold liquid is passing down through the pipe or the pipes 7, the warmer liquid in the inner space in the lower container Kvf will, through one or more other pipes 8 for return of liquid, ascend to the upper container B, as indicated by the arrow 9. This second pipe or these second pipes passes/pass from the upper part of the lower container Kvf or from the upper inner surface of the inner space of the lower container Kvf up to the inner space of the upper container B. A circulating flow has been started and will continue as long as there is liquid in the upper container that is colder than the liquid in the lower container. Thus, the circulating flow will continue for all the time as long as the second part T2 of the unit pipe R is not heated, i.e. in the special case all night until sun again is illuminating the unit pipe R at the second part T2 thereof that is located outside the upper container B. During this continuing circulating flow the temperature of the liquid Ll in the upper container will rise and the temperature of the liquid L2 in the lower container Kvf will decrease and the lower container Kvf will store a sufficient quantity of cold liquid to be capable of cooling the user H, for example a building or an office, the following day.

Also the lower container Kvf should be located so that layered differences of the liquid temperature vertically are actually obtained in the same way as for the upper container B.

The delivery of cooling to the user H, for example a building, is shown in Fig. 3. The function of the system when cooling is delivered is as follows: When cooling is desired, a valve Vl is opened in a first pipe 11 extending downwards from the bottom of the lower container Kvf. Then the cold liquid in the lower container Kvf will, as indicated by the arrow 13, flow downwards through this pipe and the valve Vl up to and into the system for cooling, not shown, of the user H, for example of the building. Due to differences in density between hot and cold liquid and the effect of gravitation, warmer liquid will return in a second pipe 12 for return of liquid as indicated by the arrow 15, from the distribution system of the user. Thus, the user H is cooled by the circulating flow occurring only due to the gravitation and the density differences of hot and cold liquid, i.e. by self-circulation. Cooling can here be delivered with a typical temperature between for example 5 and 10° C when using unit cells according to the above mentioned International Patent Application. The system is also shown in its charging state during daytime in Fig. 4 and in discharging, i.e. in the night, in Fig. 5. The unit cell R, which can be a battery of unit cells arranged in parallel with one another, is here illustrated having its outer end T2 located in a solar energy collector 17 on the roof of the building H. The inner first end Tl of the unit cell is as in Figs. 1 - 3 located in the upper part of the upper container B and the cooling flange Kf is through pipes also connected to the upper part of the upper container. As shown, the first pipe 7, which connects the upper container to the lower container Kvf and is intended to transport, in the discharge stage, cold liquid from the upper container to the lower container, should start from the bottom of the upper container B and end somewhere in the inner space of the lower container, for example approximately in the central area thereof or somewhat thereabove vertically. In the same way the second pipe 8 that also connects the upper container B to the lower container Kvf but is intended to transport, in the discharging stage, relatively warm liquid from the lower container to the upper container, should start from the upper wall or the roof of the inner space of the lower container, i.e. from the uppermost part of this container, and end somewhere in the inner space of the upper container, here also for example in the central area thereof vertically. The corresponding arrange- ment is also valid for those pipes that connect the lower container Kvf to the distribution system of the user H, the first pipe 11 in particular starting from the bottom of the inner space of the lower container and the second pipe 12 ending somewhere centrally in the middle region of the inner space of the lower container.

While specific embodiments of the invention have been illustrated and described herein, it

is realized that numerous other embodiments may be envisaged and that numerous additional advantages, modifications and changes will readily occur to those skilled in the art without departing from the spirit and scope of the invention. Therefore, the invention in its broader aspects is not limited to the specific details, representative devices and illustrated examples shown and de- scribed herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. It is therefore to be understood that the appended claims are intended to cover all such modifications and changes as fall within a true spirit and scope of the invention. Numerous other embodiments may be envisaged without departing from the spirit and scope of the invention.