Pool and Spa Chemicals Online Shop , Pumps, Accessories Perth

SOLAR POOL HEATING

 

Installing solar pool heating can increase the use of your pool by up to four months. By using the

heating energy from the sun, the cost to heat a pool in this way is very economical. The type of

solar system may vary, however, the basic principal remains the same. Pool water is circulated

through a series of tubes (the collector) usually mounted on the roof, where heat is absorbed and

the heated water returned to the pool. The collector can be of either EPDM Rubber or PVC/TPR

material and is usually supplied in multiple tube "strips". The amount of heat absorbed and the

ultimate increase in pool water temperature depends on several factors which should be

considered when deciding on a solar heating system for your pool. They are;

• Size or area of collector and number of tubes per sq.m

Naturally the major influence on the effectiveness of any solar system is its exposure to the sun,

therefore,

• Location or positioning of collector

• Control system

 

SIZE OR AREA

The amount of collector used in your solar system will have a major influence on the effectiveness

of the system. The size of the collector is usually expressed in square metres, and as a general

rule, directly relates to the surface area of the pool.

The area of collector generally needs to be increased depending on variables such as; local

climate, shading of roof or pool, slope and orientation of roof, wind protection, type and colour of

roof and collector type.

Larger systems will be needed where higher than average water temperature, or extended

swimming season is desired.

In accordance with the above, a minimum area of 80% is recommend for the majority of

installations.

The "area" referred to in relation to collector size is the area of actual collector strip NOT the roof

onto which it is to be placed.

Australian Standard 3634 details the way in which the effective width of collector strip is to be

determined for calculating collector area.

ie.

The formula is N x (W + D) where N = number of tubes, D = tube diameter and W = web width

between tubes. ( The maximum web width which can be used is no more than one tube diameter

per tube).

 

LOCATION AND ORIENTATION

Collectors (other than those on flat roofs) should ideally be placed on north facing roofs. Deviation

is allowable as long as collector area is increased accordingly. Collector should be located so as

to avoid shade from objects ie; trees, neighbouring houses etc for at least six hours every day.

Remember, the following will all effect the size and location of your solar system;

• Pool surface area

• Roof orientation

• Shade on collector or roof

• Colour of roof and pool

 

PUMPING REQUIREMENTS

To circulate water through the solar system you can choose to use either the existing pump or

provide a dedicated pump.

If the existing pump is to be used it must meet the following conditions;

(a) the required rate of turnover of the pool water for filtration purposes shall be

maintained,

(b) the operating pressure of the filter shall not be increased above the manufacturer's

maximum pressure by the addition of the solar circuit and

(c) the pump shall have sufficient capacity to handle the static head and friction losses

introduced by the addition of the collector circuit.

The average domestic solar installation requires a minimum flow rate of around 100 to 200 litres

per minute to operate effectively. In most circumstances this would mean a dedicated solar pump

would be required.

Always check that the minimum design flow rate of the collector is met when selecting your pump.

This flow rate will vary with the diameter of the tubing used.

The circulated water needs to be strained to avoid blocking up the collector with dirt and debris, so when using a dedicated pump, some form of strainer must be provided.

 

SOLAR CONTROLLERS

As nobody can guarantee at what time of the day the sun will actually shine, time clocks are of

little use in controlling solar heating systems. What is needed is a temperature sensing control

device. These units will operate the solar pump system only when heat can be gained. This

ensures that maximum heat gain is acquired.

Circulating water through a cold collector will cool the pool at a faster rate than it can be heated.

 

HANDOVER AND DOCUMENTATION

At the time of handover, the pool owner should be provided with an appropriate document

certifying that the system has been installed and commissioned satisfactorily.

The owner should receive documentation covering;

(a) A list of all major components, including the size and make of solar collector, make and

model of the control system, components and pump.

(b) Copies of all warranties as issued by the manufacturers of the components and any

warranties issued by the installer should also be provided.

(c) Operating, preventative maintenance and service instructions describing start up, normal

running and shut down procedures in an easily understood form.

(d) A record of the date of the installation and the name and address of the contracting installer.

Using a pool blanket can increase the benefits of solar pool heating.