By adding a solar pool heater, you may drastically cut your swimming pool heating expenses. They have very low annual operating expenses and are priced similarly to heat pump and gas pool heaters. In some climates, solar pool heating is really one of the most economical uses of solar energy.
How They Operate
The majority of solar pool heating systems consist of the following:
- A solar collector is the apparatus that circulates pool water through the sun’s heat.
- A rendering of a solar panel Arrows depict the flow passing through one tube, across the panel, and out the other tube, which is designated the header/manifold, which is located at either end of the panel.
- Before water is pumped through the collector, a filter eliminates particles.
- Water is pumped back into the pool after passing through the filter and collector.
- A flow control valve that directs pool water through the solar collector, either automatically or manually.
Filtered pool water is then returned to the pool after being heated by one or more solar collectors. By running water through the collector(s) at night in warmer climes, the collector(s) can also be utilized to chill the pool during the hottest months of the year.
Solar pool collectors are made from a variety of materials. Depending on your environment and how you plan to utilize the collector, you’ll need to choose a certain type. Typically, if you only use your pool while the temperature is above freezing, you won’t require an unglazed collector system. Unglazed collectors are those without a glass cover (glazing). The panels are frequently made of durable rubber or plastic that has been treated with an ultraviolet (UV) light inhibitor to extend their longevity. Due to its inexpensive construction materials and simple design, unglazed collectors are often less expensive than glazed collectors. These unglazed systems might even be useful for indoor pools in cold climates if they are designed to drain back into the pool when not in use. Unglazed collectors may be more cost-effective than installing a more expensive glazed collector system, even if you have to shut the system down during cold weather.
Glazed collector systems often use an iron-tempered glass covering over copper tubing on an aluminum plate, which raises the price of the system. Glazed collector systems, which include heat exchangers and transfer fluids, are more effective than unglazed collector systems for capturing solar heat in cooler climates.
They can therefore be utilized all year long in various conditions. Domestic hot water can be heated all year long using glazed collectors.
If they will be utilized in colder climates, all glazed and unglazed collector systems must have freeze protection.
How to Choose a Solar Pool Heater
A solar pool heating system normally costs between $2,500 and $4,000 to buy and install. Depending on your local fuel prices and the amount of solar energy you have access to, this offers a payback period of between 1 and 7 years. They typically last longer than pool heaters powered by gas or heat pumps. Your real cost and payback are influenced by a number of variables. Therefore, you should carry out the following before you buy and install a solar pool heating system:
- Determine the appropriate system size by evaluating the solar resource at your site.
- Identify the collector’s proper alignment and tilt.
- Analyze the system’s effectiveness.
- Specify system costs.
- Look into any local ordinances, covenants, and rules.
Analyzing the Solar Resource on Your Site
Consider your site’s solar resource before you purchase and install a solar pool heating system. Depending on how much solar energy reaches your construction site, a solar pool heater’s effectiveness and design will vary.
Both direct and diffuse sun rays are used in solar pool heating systems. Therefore, even if you don’t reside in a region with a temperature that is generally warm and sunny, such as the southwestern United States, your site may still have a sufficient solar resource. Basically, your development site is an excellent option for a solar pool heating system if it has open spaces and often faces south.
A solar site analysis might be carried out by your neighborhood solar system supplier or installer.
How to Size a Solar Pool Heater
A solar pool heating system’s size depends on a number of parameters, including:
- Pool size Swimming season length.
- Regionally typical temperatures.
- Ideal pool temperature.
- Solar resource on the site.
- Collector efficiency, orientation, and tilt.
- Utilizing a pool cover.
- To help with system requirements and collector sizing, solar system contractors employ worksheets and computer tools.
In general, your solar collector’s surface area should match your pool’s surface area by 50% to 100%. You might need to adjust the ratio between the collector area and the pool surface area in cooler and cloudier regions. Additionally, extending collector space lengthens the swimming season.
For instance, in order to accommodate year-round use, a 15 by 30 foot outdoor swimming pool in Florida normally needs a collector that equals 100% of the pool’s square footage. 450 square feet of collectors are covered by this. Since most residents of northern California only utilize outdoor pools for 6–8 months of the year, systems are normally sized at 60%–70% of the pool’s surface area.
Using a pool cover often allows you to reduce the necessary collector area in any environment.
For a solar system, you’ll also need a pool pump that is the right size. To transfer the pool’s water to and through the collectors if you’re switching to a solar pool heating system, you might need a bigger pump than your current one or a different, smaller pump.
Placing the Collector for a Solar Swimming Pool Heater
Collectors can be installed on rooftops or anywhere else close to the pool that offers the right exposure, tilt, and orientation to the sun. The effectiveness of your solar pool heating system will be impacted by the collector’s tilt and orientation. When assessing the solar resource on your site and sizing your system, your contractor should take these factors into account.
Orientation for Collectors
a picture that demonstrates collector orientation. The collector should be pointed directly south, though it can also be pointed up to 15 degrees east or west of south.
Geographically oriented solar pool heater collectors will receive more daily and seasonal solar energy than those that are not. True south is typically the best position for a solar collector in the northern hemisphere. Recent research has revealed that your collection can face up to 45 degrees east or west of true south without severely degrading its effectiveness, depending on your location and collector tilt. You should also take into account things like roof orientation (if you intend to mount the collector on your roof), nearby landscape features that provide daily or seasonal shade, and regional weather conditions (cloudy mornings or afternoons), as these aspects may affect the ideal orientation of your collector.
Tilt for Collector
Depending on how long your swimming season is, an image shows the appropriate collector angle at plus or minus 15 degrees of latitude.
Depending on your latitude and the length of your swimming season, you need tilt a collector at a different angle (summer or year-round). The ideal tilt for collectors used for summer-only heating is equivalent to your latitude minus 10° to 15°. Collectors for all-year heating should be angled at a latitude-equal angle. However, research has demonstrated that system performance won’t be greatly affected if a collector is not slanted at the ideal angle. Since this is the case, you can typically put collectors flat on your roof, which may not be at the best angle but is more aesthetically beautiful. However, when sizing your system, you’ll want to consider the roof angle.
Analyzing the Solar Swimming Pool Heating System’s Efficiency
If the thermal performance rating of the collector is available, you may use that information to calculate the effectiveness of a solar swimming pool heating system.
British thermal unit (Btu) per square foot per day is used to rate the thermal efficiency of solar collectors: Btu/ (ft2day)
A different way to express the rating is in kilowatt hours (kWh) per square meter per day: kWh/ (m2day).
Additionally, it can be expressed in Btu per day, which is just the rating in Btu/(ft2day) times the area in ft2. The rating in kWh/(m2day), which is the area in m2 times the rating in kWh/(m2day), is also used.
The efficiency of solar energy gathering increases with the number. The thermal performance of any two collectors, however, should be regarded as being roughly the same if their ratings are within 25 Btu/(ft2day) of one another because weather circumstances, instrumentation accuracies, and other test condition restrictions can differ.
High efficiency solar collectors may also need fewer square feet of collector area to heat the pool in addition to lowering your annual operating costs.
Cost comparison of solar pool heating systems
You may calculate and compare the expenses of employing various solar collector models before investing in a solar pool heating system. This will enable you to estimate the possible cost savings of purchasing a more effective collector, which would need fewer panels to cover the required collector area to heat your pool.
You must be aware of the following in order to estimate and compare costs:
- The thermal performance rating (Btu/day) of a collector
- Total required for the area’s collector panels or piping to heat your pool
- Total system installation cost.
The following formula can be used to determine a collector’s energy output per dollar invested or spent:
Total installed system cost (Btu/day X the number of collector panels or piping modules) Equals Btu/$ for every dollar spent.
The following formula can be used to determine the energy output for each dollar spent or invested for various collectors if you only know the pricing and thermal performance ratings (Btu/day) of collectors:
Collector price x Btu/day = Btu/day for each dollar spent
A solar pool heating system or collector shouldn’t be chosen based entirely on projected costs. The size of the system, as well as the caliber of the design and installation, should all be taken into account when choosing a solar pool warmer.
Codes and Covenants for Buildings
As with solar water heating systems, it’s crucial to take local building laws and ordinances into account. The solar rating and certification organization (SRCC), which assigns ratings for solar pool heaters in accordance with the OG400 standard, also keeps a list of solar pool heaters that have received certification.
Installation and upkeep
There are numerous variables that affect how well a solar pool heating system is installed. Solar resource, climate, local construction code restrictions, and safety concerns are a few of these variables. The best option is therefore to have your system installed by a certified solar thermal systems contractor.
Your system will continue to function correctly for 10–20 years after installation if it is properly maintained. For maintenance requirements, talk to your contractor and check your owner’s manual. If the filtering system and chemical balance of the pool are routinely monitored, your collector shouldn’t need much maintenance. In dry locations where rainwater doesn’t act as a natural rinse, glazed collectors might need to be cleaned.
Ask the following inquiries while vetting possible installers and/or maintenance providers:
- Has your business ever set up and maintained solar pool heating systems? Select a business that has previous expertise servicing and installing the applications you’ve chosen.
- How long has your business been installing and maintaining solar heating systems? The better, the more experience. Ask for a list of previous clients who are willing to serve as references.
- Is your business accredited or licensed? In some states, having a current license as a solar contractor or plumber is necessary. To learn more, get in touch with your county and city. Consult the contractor licensing board in your state to confirm your license. You can learn more about any complaints made against state-licensed contractors through the licensing board.
Swimming Pool Solar Heaters Ratings