GB2103785A

GB2103785A - Solar heating mat for swimming pools

Info

Publication number: GB2103785A
Application number: GB08222248A
Authority: GB
Inventors: John Eric Welford
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-06-18
Filing date: 1982-05-24
Publication date: 1983-02-23

Abstract

My invention comprises a mat made of black pigmented PVC hose pipes arranged side by side lengthwise. At one end the pipes are connected to the manifold at the bottom of a water tank supplied by pump from the pool. At the other end the pipes are raised above the level of the inlet end so that they are kept always filled with water. A differential temperature controller ensures that the pump operates only when the water in the mat is at a temperature higher than the temperature of the pool.

Description

SPECIFICATION Solar heating mat for swimming pools This invention is concerned with the heating of swimming pools by solar energy.

The generally established method of heating the water in swimming pools by solar energy is to pump the water from the pool through channels or pipes in contact with rigid elevated panels exposed to the radiation from the sum whereby the water is warmed and returned to the pool. The panel system suffers from the following disadvantages: i) The cost of panels and the necessary fixing structure is high in relation to the amount of energy obtainable.

ii) An area has to be provided for siting the panels.

iii) Exposure to wind can cause loss of heat.

iv) Exposure to frost necessitates complete drainage to avoid damage.

It has been proposed to use specially constructed envelopes through which water can flow and be heated when the device is exposed to the sun. Such devices are difficult to manufacture and install if they are made large enough to provide heating for the average swimming pool and a special area has to be provided for supporting such devices.

It is the object of the present invention to avoid all the above disadvantages by using hose pipes arranged in the form of a mat on the ground instead of elevated panels. It has been observed that black pigmented plasticised PVC hose pipes have survived continuous outdoor exposure for fifteen years without significant deterioration. Moreover when stuck side by side on a suitable base and filled with water the hose pipe mat so formed may be walked on without distortion or damage to the matting.

Furthermore trials under various weather conditions have shown that the solar energy collected and transmitted as warm water is as great with this matting as with panels of comparable area facing the sun's rays. One end of the hose pipe assembly is connected into the manifold at the bottom of a tank fed by a pump with water from the pool. In order to ensure freedom from air bubbles the outlet end of the assembly of pipes is raised over a bar to a level slightly above the level of the inlet end so that there is a small hydrostatic pressure maintained in the pipes.

A differential thermal switch ensures that the pump taking water from the pool only operates when the temperature of the hose pipe mat is at least 20C higher than the temperature of the water in the pool.

The rate of flow of water through the pipes comprising the mat needs to be adjusted in relation to the length of the mat if the optimum conversion of solar energy to heat is to be attained. At low rates of flow the temperature of the mat rises above that of the air layer adjacent to the mat when it is exposed to radiation from the sun. The temperature differential results in loss of heat by conduction to the air and by infra red re-radiation. At high rates of flow the temperature of the mat remains low throughout its length and although there are no losses to the adjacent air the outlet temperature of the water may not be high enough. The importance of flow rate and the results obtainable from a solar heating system as previously described are illustrated in Examples 1 and 2 below.

Example 1 50 Black plasticised PVC hose pipes each 12 mms internal diameter and 1 5 mms in length were fixed adjacent to one another on a woven polypropylene sheet to form a mat horizontally disposed lengthwise in a NE-SW direction. At one end of the mat so formed the ends of the hose pipes were joined into the bottom outlets of a tank into which the cold water was pumped. At the other end of the mat the hose pipes were raised on a ramp and held at a level 120 mms above the level of the bottom outlets of the cold water tank. The level of the water in the cold water tank varied from 1 80 to 280 mms in accord with the rate of flow of water through the pipes.

The time of this test was April 1 7th 1 5.00 to 15.30 hours GMT. Shade temperature 1 4.90C.

location was Surrey and the sky was clear Water flow Temperature Heat collected lltres/minute in out kilocalories/minute 7.5 14.00C. 20.1 or. 45 75.0 14.00C. 15.80C. 135 Example 2 The time of this test was June 22nd 11.30 to 12.30 hours GMT. Shade temperature 1 8.90C.

Other conditions as in Example 1.

Water flow Temperature Heat collected litre/minute in out kilocalories/minute 9 18.00C. 26.70C. 78 18 18.00C. 25.00C. 126 22 18.00C. 23.50C. 121 27 18.00C. 22.7"C. 127 54 18.00C. 20.2"C. 119 No insulation is used with the solar heated mat because it is operated at temperatures no higher than the temperature of the surrounding air which tends to be stagnant and warm.

Claims

1. A solar heating mat for swimming pools comprising a number of black pigmented plasticised PVC hose pipes arranged side by side lengthwise so that the water flowing through the pipes becomes warm when the mat is exposed to the sun and is then returned to the pool.

2. A solar heating system for swimming pools as claimed in claim 1 wherein a differential temperature controller operates the pump only when the sensor in the pool registers a lower temperature than the sensor in the water in the pipes.

2. A solar heating mat for swimming pools as claimed in claim 1 wherein one end of the pipes comprising the mat is connected to the manifold outlet at the bottom of a tank supplied with water from the pool by means of a pump and the other end of the pipes is raised above the level of the tank manifold so that the pipes remain full of water when no water is flowing.

3. A solar heating mat as claimed in claim 2 wherein a differential temperature controller is used and adjusted so that the pump takes water from the pool only when the sensor in the mat is at a higher temperature than the sensor in the pool.

New Claims or Amendments to Claims filed on 5 November 1 982.

Superseded Claims 1-3.

New or Amended Claims:

1. A solar heating system for swimming pools whereby water from the pool is pumped to an open tank fitted at the bottom with outlets to which are connected a number of flexible pipes horizontally disposed under radiation from the sun. At the open ends the afore-said pipes are raised to a level above the level of the tank outlets and below the level of the water in the tank. The water flowing from the tank through the pipes can be arranged to discharge direct to the pool or into a trough feeding the pool.