17 minute read
Pool heating feature — heating alternatives
WHAT A GAS HEATING ALTERNATIVES: GAS
Despite Australia’s reputation as the land of eternal sunshine and long hot summers, most backyard pools benefit from the installation of a heating system. Swimming pool heating can significantly extend your swimming season — in some cases by months. In this issue, we’re looking at the three main types and the features and benefits offered by each.
Much the same as air conditioning, there are ideal temperature setpoints for swimming pools, depending on the type of activity for which they are used. For leisure swimming, it’s between 24 and 26°C and a little higher for exercise, at around 28°C. Hydrotherapy pools are generally heated to between 32 and 35°C to deliver the optimum environment. Of course, these temperatures are not easily achieved without intervention and most pools sit somewhere between 18 and 22°C during the swimming season. Any heat gained during the course of the day is quickly lost after nightfall, leaving the pool cold again come morning.
One of the quickest ways of warming your swimming pool is to use gas heating, allowing you to extend the swimming season and enjoy the pool for longer, while also increasing return on your investment. The increased availability of natural gas and liquid petroleum gas (LPG) has made gas heating an increasingly popular choice. Because supply is always available and can be closely regulated, gas is ideal for use in pools and spas where specific temperatures are desired.
HOW IT WORKS Gas pool heaters use either natural gas or LPG. As the pump circulates the pool water, it is drawn from the pool and passes through a filter to the heater. The gas burns in the heating unit’s combustion chamber, generating heat which is then transferred to the water that is returning to the pool.
ADVANTAGES Gas is ideal for heating quickly and the most efficient method for heating pools and spas in short periods of time, as they can reach the desired temperature quickly and maintain that setting regardless of ambient conditions.
SIZING The size of a gas heater is expressed by its input rating — a measure of its fuel energy consumption in megajoules (MJ) — and by its output rating measured in kilowatts (kW). Small heaters are in the range of 60 to 100 MJ and larger units between 250 to 400 MJ. Heater output ranges between 25 and 100 kW.
Consider the following factors when determining the most appropriate gas heater size for your application: • Desired temperature — this is personal choice, but as a guide the following temperatures are suitable for each type of pool: - pools used for social swimming or exercise — 24 to 28°C - therapeutic pools — 28 to 35°C
- spa pools — 34 to 38°C • Water volume — determine volume by multiplying the surface area (pool length x width) by the average depth including wading areas and spa (if applicable) • Acceptable waiting times — how long you are prepared to wait for water to reach the desired temperature • The use of heat-retaining accessories — whether you utilise a pool cover or blanket When determining swimming pool water volumes, don’t forget to factor in the spa. Most people want to heat the spa more quickly (and to a higher temperature) than the pool, so the ultimate choice should take this into consideration. For applications that only require pool heating and time is less of an issue, a smaller heater may suffice.
INSTALLATION AND OPERATION Gas heaters are available in a range of configurations designed to suit specific conditions, including indoor and outdoor positioning. Indoor installations require fluing and adequate ventilation for the size and type of heater being used. Heaters designed for outdoor use should not be used indoors.
Though most heaters are designed and constructed to operate in all conditions, appropriate consideration should be given to protection from the elements and the manufacturer’s installation recommendations always followed. Heaters should be installed on a stable non-combustible base, preferably 50 mm or more above ground level.
THINGS TO KNOW AND LOOK FOR Most gas heaters available today are fitted with thermostatic controls. Heaters connected to spas must have a thermostatic control with a maximum temperature set to 40°C.
As with other heating types, various makes and models offer differing degrees of control and options. While budget is always a consideration, be sure to factor in your lifestyle and usage patterns when assessing alternatives and be sure not to overlook any longterm benefits in favour of a short-term cost-based decision. If you aren’t sure, or would like further advice, consider speaking with a SPASA member, who can point you in the right direction.
SAFETY Given the combustible nature of gas, there are specific safety considerations: • Chemicals — including pool chemicals — must not be stored in the same room as a gas heater • Spa blowers must be located a minimum of 1.5 m from an installed gas heater
A final note: Care should be taken when using gas heaters in salt chlorinated pools. Ensure that the production of chlorine is adjusted to suit, as excessive salt and/or chlorine levels can damage internal components. This is particularly important when operating for extended periods during heat-up.
With summer coming to an end, the time that you spend in your pool shouldn’t. Imagine swimming in comfort all year round or even just extending your pool season. With Pentair’s UltraTemp heat pumps, you can do that by automatically heating your pool to the desired temperature, so you can always swim in comfort.
How does it work? The UltraTemp essentially steals heat from the air and transfers it to your pool with incredible efficiency. Unlike solar pool heating, UltraTemp heat pumps can reliably heat your pool rain, hail or shine!
UltraTemp features easy-to-use digital controls with dual thermostats that offer precise temperature control for pool/ spa combinations, avoiding overheating and energy waste. Self-diagnostic con
YEAR-ROUND COMFORT
trols monitor and troubleshoot heat pump operations to ensure safer, more dependable operation. The unit’s long-life and corrosion-resistant composite cabinet retains a like new appearance for years.
The UltraTemp heat pump offers best-in-class efficiency with COP (coefficient of performance) ratings far in excess of standard heat pumps. Featuring rotary and scroll compressors that are more efficient, durable, reliable and quieter than any others. They really are the best of the best. Features include: • 100% titanium heat exchanger assures corrosion-free performance for extra-long life and value • LCD control displays an intuitive, menu-driven readout with easyto-follow icons and messages • Self-diagnostic software continuously monitors system for peak performance • Thermostatic Expansion Valve (TXV) controls refrigerant flow for optimum efficiency and kW output over a wider operating temperature range • Automatic defrost feature senses refrigerant temperature and helps prevent the UltraTemp heat pump from freezing, allowing the unit to operate effectively at even lower temperatures than many competing products • Perfect companion to IntelliTouch® or EasyTouch® Control Systems — heat pump control can be transferred to a centralised control system that manages all your pool/spa operations and poolscape features. Visit pentairpool.com.au for more information.
UNDER THE SUN
HEATING ALTERNATIVES: SOLAR HEATING
Solar is a popular option, providing a cost-effective and sustainable swimming pool heating solution in the right climatic conditions.
Australia’s solar power uptake rates are among the highest in the world, with some homeowners choosing to capitalise on that investment and add pool heating into the mix.
Australia’s dry, sunny climate lends itself to swimming pool solar heating, with many home owners taking advantage of plentiful sunshine to power their homes and save on electricity.
HOW IT WORKS The specifics of the type of solar system you choose will vary, but the basic principles are the same. Pool water is circulated through the solar collector — a series of tubes generally mounted on the roof — where heat is absorbed and heated water is returned to the pool. The collector is constructed from either EPDM rubber or PVC/TPR material and is usually supplied in multiple tube strips or panels.
ADVANTAGES Harnessing the power of solar energy is an economical pool heating solution, allowing you to increase pool usage by up to four months, depending on your location. Beyond the initial outlay, annual running costs for a solar system are minimal.
SIZING, LOCATION AND ORIENTATION Obviously, the amount of heat absorbed is heavily dependent on the size, location and orientation of your solar system. There is a little more calculation and pre-planning required for solar heating than other alternatives: size and area, positioning and the type of solar controller to use. SIZE OR AREA The size of the solar collector is a major determiner of overall system effectiveness. It is usually expressed in square meterage and, as a general rule, relates to the surface area of your pool.
There is no hard-and-fast rule, as a range of variables will determine the square meterage required. These variables include
local climate, shading of the roof or pool, type, colour, slope and orientation of the roof, wind protection and the collector type. Recommendations generally come with the proviso that they apply only in ‘ideal’ conditions. Australian Standard AS 3634-1989: Solar heating for swimming pools provides guidance for the minimum acceptable collector area in ideal conditions. This varies by geographic location and uses a simple estimation. A rule of thumb is at least 60% of pool surface area (length x width) for FNQ/NT, 70% for Brisbane, Alice Springs/ parts of WA and 80% for NSW, ACT, Vic, SA, Tas and Perth.
When higher than average water temperatures or a significantly longer swimming season are the desired goals, opt for a larger solar collector area — equivalent to 80% of the pool surface. It is important to note that ‘area’ in this context means the actual collector strip area, not the roof surface area. AS3634 details solar collector calculation methods as follows: N x (W+D), where N = number of tubes, D = tube diameter and W = width between tubes. The maximum web width that can be used is no more than one tube diameter per tube.
© Stock.Adobe.com/au/vege
LOCATION AND ORIENTATION Other than in flat-roof installations, solar collectors should be placed in a north-facing position where possible. If the site does not permit a north-facing orientation, the collector area should be increased to compensate. Ideally, the collector will be located in a position free from shade caused by trees, neighbouring houses and other structures for at least six hours per day.
THINGS TO KNOW AND LOOK FOR
PUMPING REQUIREMENTS
WWW.SPASA.COM.AU When using the existing pump, you will need to ensure the following conditions can be met: • The required rate of turnover of the pool water for filtration purposes must be maintained. • The operating pressure of the filter must not be increased above the manufacturer’s maximum pressure by the addition of the solar circuit. • The pump must have sufficient capacity to handle the static head and friction losses introduced by the addition of the solar collector circuit. The average residential solar installation requires a minimum flow rate of around 100 to 200 litres per minute to operate effectively. In most circumstances this means that a dedicated solar pump is required. When assessing pump alternatives, check that the minimum design flow rate of the solar collector will be met and be aware that this will vary with the diameter of tubing being used.
Circulated water must be strained to avoid blocking the solar collector with dirt and debris. This requires use of a strainer when opting for a dedicated pump. SOLAR CONTROLLERS There is little use for timeclock control in a solar heating system, as there is no guarantee of sunshine at any particular time of day. Temperature sensing control devices should be used, allowing operation of the solar pump system only during times when heat can be gained, as circulating water through a cold collector will cool the pool at a faster rate than it can be heated. HANDOVER AND DOCUMENTATION Once installed by a licensed electrician, you should receive documentation that confirms the system has been installed and commissioned according to local requirements. Handover documentation should include: • A list of all major system components, including the size and make of solar collector, make and model of the control system, components and pump. • Copies of all warranties as issued by the component manufacturers, along with warranties issued by the installer. • Operating, preventive maintenance and service instruction documents that describe start-up, normal running and shutdown procedures. • A record of the date of installation and the name and address of the installer.
A final note: Using a pool blanket will increase the benefits of solar pool heating as it traps in the heat and additionally minimises evaporation. Covers and blankets are available in a range of styles from simple manual types through to fully automated options.
PUMP IT UP HEATING ALTERNATIVES: HEAT PUMPS
Electric heat pumps are another popular choice, delivering warmer water even while the sun doesn’t shine.
Electric pumps extract heat from the air and use it to produce hot water. They are available in two types: on/ off and inverter.
HOW IT WORKS Heat pumps feature three main parts: a fan, an evaporator and a condenser.
Water is circulated by the pool pump, passed through a filter and drawn through the pump heater. The heat pump draws in air and directs it across the evaporator. Refrigerant absorbs heat from the outside air and warm gas then passes through the pump’s compressor. The compressor increases gas heat and passes it through the condenser. The condenser transfers the gas heat to the cooler water circulating through the heater and that heated water returns to the pool. The hot gas returns to liquid form as it flows through the condenser and back to the evaporator, allowing the entire process to begin again. On/off heat pumps are self-explanatory — they run at 100% heating capacity when on and 0% when off. Inverter heat pumps adapt compressor and fan speeds up or down depending on the pool temperature requirements, which can offer greater efficiency through reduced heating times and running costs.
ADVANTAGES The major advantage of heat pumps is that they are an extremely energy-efficient alternative. This is because the pump itself requires very little energy (in the form of electricity) to operate when compared with the amount of energy (in the form of heat) that it produces. The energy efficiency is measured by coefficient of performance (COP), a ratio of energy consumption to production. COP is expressed as a whole number and the higher that number, the more efficient the pump. For
example, a heat pump that consumes 2 kW of electricity that produces 10 kW of heat energy has a COP of 5.0. This is because for every unit of electricity it takes to run, it generates five units of heat.
SIZING Swimming pool heat pumps are available in a range of sizes. You’ll need to consider the following factors when determining the most suitable option for your application: • Location — ambient climatic conditions will have a huge influence. • Desired temperature — this is personal choice, but as a guide the following temperatures are suitable for each type of pool: - pools used for social swimming or exercise — 24 to 28°C, - therapeutic pools — 28 to 35°C, - spa pools — 34 to 38°C. • Water volume — determine volume by multiplying the surface area (pool length x width) by the average depth including wading areas and spa (if applicable). • Shading and wind exposure — both will affect the heat losses and gains of heated water. • Position — an indoor or outdoor location. • Desired season — determine if you would like to swim year-round or just to extend the season by a few weeks in autumn and/or spring.
INSTALLATION AND OPERATION Heat pumps can be located indoors or out, as long as appropriate airflow and ventilation are available in the chosen location. Heat pumps use a fan to draw in air and to expel it, so adequate ventilation is required for indoor installations.
Outdoor installations can be positioned at ground level (a 50 mm plinth is recommended), mounted on a wall or on a roof.
Heat pump units can be included as part of the pump and filter network or plumbed as a separate heating circuit. An average-sized residential installation will generally require a single-phase electrical connection, whereas large pools may require three-phase power.
Where possible, consider an off-peak connection to further reduce running costs.
THINGS TO KNOW AND LOOK FOR Swimming pool heat pumps will incorporate a flow control device to prevent operation when adequate water flow is not available.
Heat pumps are thermostatically controlled and are available in analog or digital formats. While both produce the same general result, digital thermostats are inherently more accurate and offer improved display settings.
As with all pool equipment types, not all heat pumps are created equal. Some will include additional features and controls such as timeclock and/or pump interlock which allow the user to ensure the most economical operation. Make sure you are comparing apples with apples when assessing alternatives. If you need more information or advice, speak with a SPASA member.
A final note: Care should be taken when using heat pumps in salt chlorinated pools. Ensure that the production of chlorine is adjusted to suit, as excessive salt and/or chlorine levels can damage internal components. This is particularly important when operating the heat pump for extended periods during heat-up.
EXTEND YOUR SWIMMING SEASON AND PREPARE FOR WINTER
The start of autumn may still bring warm swimming weather, but with a Climate Care Certified solar pool cover, you are guaranteed to extend your swimming season much further.
Regardless of the shape or size of your swimming pool, there is a solution to help stop evaporation and save time on cleaning and maintenance. A Daisy Solar pool cover can warm your pool water by up to eight degrees, allowing you to enjoy your pool for longer throughout the year.
If your pool can’t be covered, or is only partially covered, Daisy AquaSaver is the answer. AquaSaver reduces heat loss by forming a harmless, ultra-thin invisible liquid surface barrier, reducing evaporation and extending the swimming season even as the weather cools. Used in conjunction with a pool cover or without, AquaSaver can reduce evaporation by up to 30%. The product is Climate Care Certified, which means it has been approved by SPASA as an environmentally sustainable product.
Autumn and winter weather traditionally brings additional leaf litter and debris to backyards and pool areas. A great option for the cooler months or for pools in windy or debris-heavy environments, the Daisy WinterKleen mesh pool cover stops leaves and other debris entering when pool use is lower and heat loss is less of a concern. For some pool owners, utilising a combination of cover solutions that meet different needs throughout the year works best. To find out which options will suit your environment, save you time and money and extend your swimming season, speak with a pool expert.
DAISY POOL COVERS P: 1300 55 18 11 E: HELLO@DAISYPOOLCOVERS.COM.AU W: DAISYPOOLCOVERS.COM.AU
SPASA SPOTLIGHT: SPLISH SPLASH POOLS
Splish Splash Pools is a multi-award winning pool construction company with over 20 years’ experience delivering pools of quality, style and elegance. We have had the privilege of working with clients on a vast range of projects, from unique plunge pools in tight or difficult spaces through to large residential pools set on acreage properties. We enjoy sharing our knowledge and expertise with clients to ensure their dream swimming pool becomes a reality.
The customer brief on this award-winning project was to create a unique pool area and environment that would maximise the elevated outlook of the surrounding bush setting. Key design features include a 15m pool with raised spa and a unique graded beach entry spilling over into a wet edge and balance tank.
The pool and spa are fully automated with PCC2000 infloor cleaning, a Jandy Aqualink Controller with iAqualink, multi-coloured lights and a Remco SwimJet. Expert product selection and a focus on detail delivered this high quality pool, which was recognised as a National Gold Award winner.
SPLISH SPLASH POOLS P: 02 9651 6963 E: ADMIN@SPLISHSPLASHPOOLS.COM.AU W: WWW.SPLISHSPLASHPOOLS.COM.AU
