Can outdoor swimming pools be greener

Q: Can outdoor swimming pools be greener?
A: Yes they can… and not because of neglect!

For many years outdoor swimming pools were extremely wasteful in terms of the energy used in their filtration and heating systems. Now, because of the need to conserve our finite fuel resources and to reduce our carbon emissions, it is becoming clear that we must use more effective ways to reduce the needless consumption of energy in the operation of both domestic and commercial swimming pools.

Making Your Pool More Efficient

The key items of equipment in an out door swimming pool that are costly in terms of global warming are those which use large quantities of fossil fuel. Swimming pool equipment which consume the largest amount of energy are the pool circulating pump and the heating system. Pool filtration plant uses electricity ,gas or oil in large volume to keep outdoor swimming pools clean and warm.

Modern pool equipment and control systems have been developed to enable outdoor swimming pools to be more energy efficient and far easier to maintain.

With the undeniable fact of global warming, responsible pool owners are rightly giving greater consideration to the impact on the planet of pool ownership.

The four main areas in a pool installation where significant savings in the consumption of fossil fuels and a significant reduction in carbon emissions can be made are as follows:

1.   The pool shell
2.   The circulating pump
3.   The heating system
4.  . The conservation of heat and chemicals

The Pool Shell

It takes an amount of time to warm any pool shell (the structural walls and the floor) before the pool water can be warmed, the swimming pool shell must reach a certain temperature before there is any noticeable increase in the pool water temperature. If the pool shell is insulated, then the loss of energy from the pool wall to the colder surrounding earth will restrict the amount of energy which is wasted.

Certikin - the leading UK supplier of pool equipment supply the Heatwave range of pools which incorporate an insulated pool wall that conserves the heat in the pool water and prevents the costly energy dissipating into the surrounding ground.

The key features of the Heatwave range of swimming pools are:

Patented heat retaining thermal wall panel which restrict the transfer of energy from the swimming pool to the outside ground Panel clamp key locking mechanism – ensures wall sections are locked together tightly to minimise the heat losses between the wall panels Pool wall design requires smaller excavation reducing the amount of imported backfill required with a consequential reduction in fuel costs The insulated swimming pool wall can significantly reduce the heating costs of a swimming pool.

As a guide the following approximate savings can achieved with the installation of a Heatwave swimming pool.

Pool type Natural gas Oil LPG Electricity
Standard pool heating cost per day £4.93 5.83 8.31 13.36
Heatwave pool £0.22 £0.26 £0.37 £0.06
*Saving per season £857.30 £1014.00 £1444.54 £2323.83

*Figures are based on an outdoor swimming pool measuring 9.7m x 5.2m and installed in dry ground conditions. Calculations are based upon a seven month swimming season.


Swimming pool circulating pump


Swimming Pool Circulating Pump

In the past a swimming pool circulating pump would be left operating continually. However the cost of operating a swimming pool pump on this basis is needlessly costly and significant reductions in running costs can be made by installing a 2 speed pump. In the higher speed operation typically a Hi Flo 1.5HP pump will be operating at a speed of 3000 RPM and this speed is ideal for backwashing, rinsing the filter, for shock dosing the pool and for periods of intensive pool use. For the majority of time however the pump will be operating at a slow speed (1500 RPM) which actually improves the rate of filtration; is much quieter in operation and will save approximately 60% in the cost of electricity.

Overall the use of such a pump will result in approximate savings of 72% when used in conjunction with a pump timer, since the efficiency of modern filtration systems does not require pumps to be operating continuously.

Assuming that the pump and filter are correctly sized, then the pump can efficiently maintain the recommended water turnover in an 8 hour period.

The Heating System

The most widely used method for heating pools is probably natural gas. For a number of years it was possible to heat pools using directly fed swimming pool heaters.

These heaters were extremely inefficient and in some cases would only have an efficiency of around 40%.

Recent UK legislation requires much higher levels of efficiency from swimming pool heaters. A major development in the area of pool gas heating is the introduction the condensing gas boiler which can run on either natural gas or LPG. This condensing boiler is 94% efficient in terms of the energy consumed and the heat generated for heating the pool water. In financial terms this boiler will be approximately 30% less expensive to operate than a conventional boiler. Manufactured with an integral stainless steel heat exchanger models such as the Genie 2 from Certikin are specifically designed for swimming pool use and can be used with saltwater chlorinators if required.

The alternative to fossil fuel gas and oil heaters is the air to water Calorex heat pump. This type of heater extracts the available energy from the air and even on a cold cloudy day at an outside air temperature as low as 10 degrees Centigrade a heat pump will provide 4Kw units of absorbed heat for every 1Kw consumed.

When compared to conventional heating then there will be a saving in excess of 30% over comparable fossil fuel heaters. The greatest benefit in this type of heater is that apart from the electricity used to run the pump, fan and compressor it uses no fossil fuels, thereby conserving the dwindling fossil fuel reserves and making no carbon emissions. Even the refrigerant in the unit is CFC free - so a truly ecologically friendly heater.

The Conservation of Feat and Chemicals in Outdoor
Swimming Pools

Outdoor swimming pools lose approximately 82% of their heat through evaporation. Any measure that can be used to counter this expensive loss of energy is to be encouraged.

The first important step in conservation of energy in an outdoor swimming pool is the use of a good quality heat retention or solar cover which will save approximately 40% of heating costs.

This can cut the total heat loss from the pool water by between 50% to 90%. In addition to the conservation of energy a solar cover will substantially reduce the water loss caused
by evaporation.

greener poolIt is estimated that an average pool in the UK loses in excess of 30,000 litres of water a year through evaporative losses. With an increasing number of water meters being installed this would represent a significant additional cost to pool owners. A thermal cover contributes significantly to savings on electricity, gas and water.

A swimming pool cover is more likely to be used if it can be easily placed on the surface of the pool and readily removed. To that end the use of a cover roller or reel system is strongly recommended. A thermal cover lying on the pool surround at night does not stop evaporation!

If a good quality roller is installed it will encourage the use of the heat retention blanket and prolong the life of the cover.

Automatic Swimming Pool Covers

These types of cover fall into 2 broad categories, firstly the articulated slatted cover which floats on the surface of the pool and is supported by the bouyancy created by the air contained within the hollow sealed slats. Companies such as Roldeck and Oase have developed this type of cover over a number of years.

An automatic slatted cover is wound on and off the pool by means of an electrically powered roller into an above ground cover if the automatic cover has been fitted after the pool has been built or in a special below ground pit if the cover has been installed at the time of
the pool construction.

This type of cover provides an effective thermal cover and will also protect the pool in the winter and at the same time keep the pool secure. If translucent slats are selected for the cover then additional heat gain can be obtained by the collection of UV energy from the
sun’s rays.

If greater safety of the pool is required with this type of slatted pool cover, then handrails around the edge of the pool below the water surface should be installed to prevent the cover being pushed below the surface.

Alternatively a ledge can be built into the pool just below water level at the time of construction to provide the same safety aspect

The second type of automatic cover is of the fabric PVC variety and this is wound onto the roller by means of a hydraulically operated system with the cover being guided and retained under tension by means of cable running in tracks concealed under the coping or edge tile.

As with the slatted variety of cover this can be fitted retrospectively in a cover housing installed on the deck, or in a dedicated cover pit built behind the pool wall.

Automatic Slatted Covers and Safety Covers

Both types of cover can be operated with a remote control and the pool cover can be locked with a key switch to prevent unauthorised use.

In the summer the pool water retains it’s heat due to insulation thereby saving money on energy and chemicals with much lower maintenance.

Greater pool safety is achieved as the pool is securely protected when not in use giving peace of mind, especially to parents with young children and pets. In the winter the pool is protected from the ravages of the British winter keeping the pool both safe and clean. The swimming pool can be made ready for use quickly and easily at the start of the new season. The installation of some or all of this type of equipment will significantly contribute to the ease of operation and substantially reduce the running costs of an outdoor swimming pool.

The lower in the of gas, electricity, water and chemicals will significantly reduce an outdoor swimming pool’s impact on the earths’ finite resources.

So both the pool owner and the planet benefit!

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