GB2048460A

GB2048460A - Solar energy collection

Info

Publication number: GB2048460A
Application number: GB7915510A
Authority: GB
Original assignee: FENEMORE P
Current assignee: FENEMORE P
Priority date: 1979-05-03
Filing date: 1979-05-03
Publication date: 1980-12-10

Abstract

A solar energy collection system comprises an inflatable bag (10) having an inlet (21) and an outlet (22). The bag may comprise two sheets (12, 14) of plastics material, say polyethylene, joined together at their margins. Either or both of the sheets may be transparent. Gas or liquid may be circulated through the bag by any suitable means such as an electric fan or blower. <IMAGE>

Description

SPECIFICATION Solar energy collection This invention concerns solar energy collection.

It has been known for some time to collect solar energy in so-called "solar panels".

These solar panels are generally made of glass and the solar energy is collected by the heating of water in the solar panels by radiation from the sun.

This invention seeks to provide a simple and relatively inexpensive system for collecting solar energy.

Accordingly this invention provides a solar energy collection system comprising an inflatable bag having an inlet and an outlet, and means for circulating a gas or liquid to be heated by solar radiation in said bag.

This invention also provides a method of heating a gas or liquid comprising circulating said gas or liquid through an inflatable bag having an inlet and an outlet and exposing said bag to solar radiation.

This invention further provides an inflatable bag for use in a solar energy collection system, said bag having an inlet and outlet so that a gas or liquid to be heated may be circulated therethrough.

The inflatable bag may be conveniently be made from two sheets of flexible plastics material, such as polyethylene, laid on top of each other and joined at or near their edges to provide a bag having an inlet and an outlet.

Preferably, the two sheets are joined at one or more points in addition to at their edges to flatten the profile of the bag so that it will cover a larger area.

The bag, when deflated, can be rolled up and stored until required.

It is believed that it may be advantageous to make the bag from a sheet of transparent material and a sheet of black material, in which case in use the transparent sheet would be placed uppermost.

Alternatively, the bag could be made from two sheets of transparent material and, when in use be placed on a dark surface, such as soil or a slate roof.

A further alternative could be to use an available surface as one side of the bag and to seal a plastics sheet to the surface at its edges to provide the other side at least two gaps being left to provide an inlet and an outlet.

The plastics sheet may be joined to the surface at one or more additional points to provide an elongate passage through the bag.

Available surfaces may include asphalted, slated or tiled areas.

The system of this invention may be used in various ways, typically, the system may be used to provide a warm fluid such as air or the fluid may be kept in the bag and the heat from bag used to warm an area over which the bag has been placed, such as a crop growing field.

To enhance this latter use of the system of this invention the outlet of the bag could be closed.

It may be advantageous to provide the bag with insulating layers on either or both sides thereto to reduce heat losses.

The gas or liquid may be circulated through the bag by any suitable means such as an electric fan or blower or an engine driven fan.

This invention will now be further described, by way of example, with reference to the accompanying drawing which shows an inflatable bag for collecting solar energy.

An inflatable bag 10 is made from two generally rectangular sheets 12, 1 4 of plastics material, such as polyethylene, joined along three sides 15, 16, 1 7 by seam 18. The other side 1 9 has a seam 20 which forms an inlet 21 and an outlet 22. A further seam 24 extends from seam 20 almost to the opposite side 1 6 of the bag 10 so as to provide a passage 26 in the bag 10 which is longer than the bag. Either or both of the sheets 12, 14 may be made of a transparent plastics material.

The seams 18, 20 and 24 may be formed in any convenient manner depending on the material used to construct the bag such as by sewing, gluing or heat sealing.

In use, a fluid such as air is passed into the inlet 21 and is circulated around the passage 26. Radiation from the sun warms the air in the bag and the warm air escapes from outlet 22. To increase the temperature of the air, it may be held in the bag for a longer period before being allowed to escape.

The air may be caused to circulate in the passage 26 by any suitable means, such as an electric fan or blower or an engine driven fan.

A bag which covers an area of 30 square metres and having a rate of flow of air of 1000 cu. ft./m therethrough may produce a temperature rise of 10'C.

The warm air from the bag may be used for any drying process such as for drying crops and vegetables, e.g. grass, grain, onions, root vegetables, such as potatoes, to prevent rotting, drying timber, fish, seaweed and manure, for providing heat for growing mushrooms and for greenhouses for desalinating water, for concentrating solutions and for drying in whole crop foraging for grain.

The system of the present invention may also be used on a preheater for air which is to be further heated in another apparatus.

As well as providing warm air, the system of the present invention may also be used for storing heat until required. This may conveniently be done by including a layer of suitable material, such as water or sand, in the bag.

The heat is stored in the water or sand and by means of suitable insulation can be stored for as long as required. Alternatively, a storage layer below the bag, such as the ground or a slate roof may provide heat storage. This effect could be controlled by providing a layer of insulation between the storage layer and the bag.

It is believed that, in addition to the heating use of the inflatable bag, cooling may be achieved in a similar way, i.e. air or other fluid is passed through the bag which is situated in an area at a lower temperature or which is able to radiate to an area at a lower temperature and is hence cooled. The cooled air or other fluid may be used for cooling lettuces, cauliflowers and the like or as the condensor for a distillation process or as a precooler for any cooling apparatus.

In summary, the system of this invention may provide one or more of the following advantages: 1. The bag may be constructed from relatively inexpensive materials.

2. The bag requires little or no additional support.

3. The bag is flexible and is less likely to damage and also can be repaired quickly and easily, for example with "sticky tape''.

4. The bag, when deflated, can be rolled up and stored and so can be used for temporary or seasonal application.

5. The bag can be erected quickly and easily.

6. Low thermal inertia of the bag results in a rapid response to short periods of sunshine.

7. The system may be readily incorporated into existing drying systems.

Claims

1. Solar energy collection means comprising an inflatable bag having an inlet and an outlet whereby gas or liquid may be circulated in the bag for heating by solar energy incident thereupon.

2. Solar energy collection means as claimed in claim 1, wherein the inflatable bag comprises two sheets of flexible plastics material laid one upon the other and marginally joined together to provide a fluid passage between the inlet and outlet.

3. Solar energy collection means as claimed in claim 2, wherein the sheets are joined together at one or more positions intermediate their margins.

4. Solar energy collection means as claimed in claim 3, wherein the intermediate position(s) is or are arranged so as to provide an elongate passage between the inlet and outlet.

5. Solar energy collection means as claimed in claim 2, 3 or 4, wherein one said sheet is comprises transparent material.

6. Solar energy collection means as claimed in claim 2, 3, 4 or 5 wherein one said sheet comprises dark, preferably black, material.

7. Solar energy collection means as claimed in any preceding claim, and means for circulating gas or liquid in the bag.

8. Solar energy collection means as claimed in claim 7, wherein the means for circulating gas or liquid comprises a motor driven fan or like impellor.

9. Solar energy collection means substantially as described herein with reference to, and as shown in, the accompanying drawing.

9. A method of heating gas or liquid by solar energy, comprising circulating said gas or liquid through an inflatable bag having an inlet and an outlet and exposing said bag to solar radiation.

10. A method of heating gas or liquid as claimed in claim 9 and as described herein with reference to the accompanying drawing.