Solar pool heating - an efficient and popular use of solar energy


Wednesday, 16 April, 2014



Solar pool heating - an efficient and popular use of solar energy

For over 30 years, solar pool heating in Australia has been an efficient and popular use of solar energy, allowing pool owners to enjoy an extended swimming season with minimal running costs. Pool+Spa investigates the popular types, common misconceptions and latest developments in solar pool heating.

There are two main types of solar heating used within Australia - soft, strip or ribbon collectors, or semi-rigid panels.

Soft, strip or ribbon types of products are usually manufactured from rubber or plastic. This system is commonly installed with the water-carrying tubes within the flat ribbon, running horizontally across the roof. It is often fastened to the roof surface with an adhesive. This system has been available in Australia for more than 30 years. Because of its flexibility, soft or strip systems can be installed on most roof surfaces and onto irregularly shaped roofs.

The semi-rigid panel product is usually manufactured from polypropylene and installed with the water tubes running vertically. This enables the panels to be more easily fastened to the roof and usually incorporates a more robust method of securing the product to the roof than adhesive alone. This allows for installations on steep roofs and in windy locations. Depending on the quality of the polypropylene, this system will usually have a longer life span than a rubber or plastic strip product. However, due to the set sizes of the panels, some roofs will not accommodate a panel system.

Installation

Once a client or pool builder has selected the right type of solar pool heating for their needs and budget, the next step is installation. Most installations are relatively easy and are usually completed in one day. There are three types of installations.

1. Integrated systems are often installed on older pools and many fibreglass pools where the pool is not equipped with dedicated pipes for the solar system. The pump installed to circulate the water to the roof-mounted solar system must draw its water from the pool return line, which means the main filter pump must run whenever the solar is being used.

2. Independent or separate suction systems, where the pool has been built with dedicated suction and return pipes for the solar. This allows the pool owner to have their solar system running at optimum solar energy times (usually 9 am to 3 pm) without the need to run the filtration system. This allows the pool owner more control over the operation and in particular the opportunity to have their filter pump running at off-peak power times.

3. Divert valve systems are a variation of the integrated system and use the main filter pump to circulate the water to the solar system via an automatic diverting valve that opens to send the water to the solar system and closes when heating is not required and during periods of low solar gain. At this time the water simply returns to the pool. This system can often be used on simple, low roof installations with a minimum of pipe work. The installing company needs to ensure the filter pump can handle the extra work load. With the increasing use of variable speed pumps, this type of system will become more common.

Misconceptions of solar pool heating

Peter Haddon, CEO of Heliocol Solar, believes that, as with all consumer products, poor quality and poor installations are always going to be the cause of concern.

“Pool owners and builders need to investigate the different brands and types of products and then purchase from reputable companies with solid reputations, strong warranties and good business ethics,” says Haddon.

“Unfortunately, some solar pool heating companies are installing poor-quality products and then provide little or no backup. Of course, consumers, when buying anything from furniture to shoes to lawnmowers, also need to be less focused on the ‘best price’ and more focused on the ‘best value for money’ with the longevity of the product and warranty strength both having a major bearing on value. The cheapest price today has little bearing on your satisfaction level in three years’ time if the product has failed.”

Most systems require little or no maintenance. Some strip systems with poor-quality roof adhesion products may require annual ‘regluing’ of the strip to the roof, particularly after wind storms. Panel products that use a hose clamp connection may require the home owner to retighten the hose clamps annually.

According to Haddon, “The biggest misconception that pool owners have about solar pool heating is that it doesn’t work. Pool owners disappointed with performance will usually have a system that is undersized, not collecting enough solar energy due to poor roof selection or shading or not operating for sufficient hours per day.

“Pool owners install solar to extend their swim seasons into the spring and autumn seasons. Unfortunately, a small percentage of people expect to swim all winter because they have been ‘over sold’. These pool owners should have bought a gas heater or heat pump. Conversely, some pool owners are sold gas heaters or heat pumps by suppliers who have told them it’s cheaper to run than a solar system, leading to very disgruntled customers when high gas and power bills arrive.”

John Dixon, national sales manager at Sunbather, believes that unrealistic propaganda is fed to clients about the limitations of solar pool heating.

“Some swimming pool heating companies will say solar has limited performance; however, that is simply not true. Solar heats more pools in Australia than any other pool heater and by a country mile. That says a lot for consumer adoption and satisfaction. Solar is the only pool heater that works on true demand; that is, when the weather is warm and people want to swim, your pool is warm. Alternative fossil fuel heaters maintain the pool temperature constantly, which is not necessary and costs consumers thousands of dollars,” Dixon says.

“Another misconception about solar is the lack of understanding on how powerful the sun really is. On a warm day, solar can deliver up to three times the heat input of some gas systems or heat pumps.

“With energy costs foremost in everyone’s mind, solar is the only responsible form of pool heating. In the tropics, solar will deliver year-round swimming; and in Southern Queensland, solar will typically give 8-9 months of warm pool use, and we find that’s what most families really want.

“If a client needs to swim all year, solar can be set up as the primary heating source and coupled with a gas or heat pump to allow all-year swimming at reasonable running costs. We find the solar is often paid back in three years with reduced running costs,” added Dixon.

Michael Mansfield, from Leisure Coast and Double Bay Solar, has been working in the solar pool heating industry for over a decade and believes the biggest misconception “is that pool owners need to heat their pool when they are not going to use it”. In fact, pool owners do not need to be running their solar pool heating system throughout the winter months when they have no intention of swimming. Additionally, if they are going away for a week or two, they can also turn the system off. When they turn the system back on, it will only take a few days to reach a comfortable temperature again.

What’s new in solar pool heating?

Due to confusion in the marketplace from clients unsure of what heating system would fit their needs best, in regards to performance and running costs, the team at Sunbather recently developed an iPad application. The app, which is a quick, on-site design and appraisal system for swimming pool heating loads, factors in all variables with the particular pool site and conditions that influence heat losses or gains.

John Dixon, national sales manager at Sunbather, was behind the development of the app and says, “The app has been developed to show a client accurate unheated pool water temperatures and then compare all forms of swimming pool heating systems including solar, gas, heat pumps and covers. This gives the customer the real facts with predicted heated pool water temperatures, length of the swimming season and will also show the actual month-by-month running costs for fossil fuel heaters, such as gas and electric heat pumps.

“The app removes all of the confusion over which particular swimming pool heater is right for the client’s needs and produces the quickest and most professional design and quoting system available - all done on-site in minutes.”

A solar pool heating system as a pool’s primary heat source will allow for a longer swimming season, without the expense associated with other types of pool heating.

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