Solar heating depends entirely on the thermal energy received from the sun. As weather conditions change, the amount of thermal energy available changes. The amount of thermal energy a solar panel can absorb varies based on several criteria:
- The direction the roof faces
- The size of the panel
- The tilt of the panel
The Solar Rating & Certification Corporation (SRCC) was founded in 1980 as a non-profit organization whose primary purpose is the development of certification programs and a set of standards that all solar companies should follow. Panels are tested for BTU output, as well as ensuring collectors meet minimum safety and durability criteria. Thermal solar collectors are measured based on the standardized performance ratings for different climates. Solar thermal collectors for pool heating are evaluated on their performance in the A, B and C categories.
A category ratings are based on the energy produced on a clear day. B Category ratings are based on the energy produced on a mildly cloudy day, and C ratings are based on energy produced on cloudy days. In Phoenix, solar heating is most desired during the warm days in March, April, May, September, October and November. Those months fall typically fall within the Category B ratings, given our slightly cloudy skies and cool nights.
All things being equal (panel size and number of panels), an EcoSun solar collector will generate 360,000 BTU’s of energy per day as compared to a panel from our competitors. That’s 80% more efficient!
It is important to note a couple of things when researching panels that best fit your needs:
- What category class is the company presenting you with?
- If the company presents their best-case scenario (usually a Category A rating, clear sunny day), ask them what time year that represents. In Phoenix, we certainly don’t need to heat our pools in the summer, so having a more efficient panel during the hottest months of the year is not necessarily the right solution.
- Does the BTU output match the price?
- If another brand’s collector is higher, but only provides a small increase in BTU’s during the time of year most important to you, is the additional cost really worth it?
- When comparing panels of different sizes, it’s important to remember that the output is given for the full panel, so, if you want to compare panels on an equal basis, divide the panel output by the panel area. And remember, the EcoSun panel provides a 12% larger surface area than other panels on the market!
Heat pumps take advantage of the sun warming the air around your pool. The heat pump draws in this air and passes it over an evaporator coil which absorbs the heat. The heat is increased when it passes through a compressor and then the heat is transferred into a condenser where it is transferred into the cooler pool water.
Because heat pumps draw heat from the air they begin to lose efficiency when temperatures are below 45°-50°F which isn’t an issue for most areas, but if you do like to swim in the dead of winter you will be better served by a gas heater.
The heater will be plumbed into your existing pool pump and equipment. Water is drawn from the pool and passed through a filter to remove any material that could damage the heater. Once the water passes through the filter, it is sent through the heater. The gas burns in the heater’s combustion chamber, creating the heat that transfers to the water. The warm water is then returned to the pool.
Have you ever left a garden hose lying in the sun and turned the water on? What happened? The water left in the hose came out hot, right? Solar heating works from the same concept.
Solar collectors (or panels) are usually placed on the roof of your home. Lines that carry the water both in and out of the pool are attached and connected to your existing pool pump. The panels collect the thermal energy from the sun, which in turn heats the water as it passes through the series of collectors. The heated water is passed back to the pool through the return lines, exchanging cool water for warmer water. During the course of the day, the water in the pool can be “turned over” or exchanged at least one time, depending on the size of your pool and pump.
When selecting a gas pool heater, there are three things you should consider:
- Monthly cost and annual maintenance
The trained professionals at Aqua Science will work with you to determine the proper size gas heater for your pool and desired swim season. Many factors help determine the size heater your pool will need. Considerations include the time you’re willing to wait for a heated pool, the surface area of the pool and the difference between the pool and outdoor air temperatures. Other factors also affect the heating load for outdoor pools, such as wind exposure, humidity levels, and cool night temperatures.
There are several calculations that go into selecting the right heater. First, you must determine the desired temperature rise per hour. Our product specialists do this through the following calculations:
Desired water temperature – average air temperature = required temperature rise / required hours to heat to desired water temp = required temperature rise per hour
After we’ve calculated the temperature rise per hour, we review the size of the pool. Gas heater sizes are determined by the amount of BTU’s generated (BTU’s are defined as the amount of heat required to raise the temperature of one pound of water by one-degree Fahrenheit). The chart below determines what size heater you should consider.
Efficiency & Cost:
Heating technologies have advanced greatly, and have produced heating units that are the most efficient we’ve seen in a decade. Today’s gas heaters will heat a pool five to seven times faster than an electric heat pump or solar panels. In addition, gas heaters are generally less expensive at the time of purchase and installation than solar heating or heat pumps.
While gas heaters are efficient at heating the water quickly, the cost of natural gas or propane comes at a price. Rising costs of natural gas can influence some homeowners to look at other heating solutions, especially when it can cost a homeowner several hundred dollars each month to keep their pool heated.
No matter what heater you choose, make sure you use a solar blanket to cover your pool when it isn’t in use. The use of thermal blankets will help retain the heat, reduces water loss from evaporation, and reduces the amount of chemicals you need to add to you pool.
To learn more about your options and what pool heater is best for you, use the contact us form or call our office. We always offer no obligation, in home consultations!
Heat pumps are generally more expensive to purchase and install than natural gas heaters but are significantly less expensive to operate. When selecting a heater for your pool you should take into consideration three factors:
- Size – every pool and need is different. Work with a professional to ensure the right size heater is installed at the onset. Undersized heaters have to work harder to heat the pool, which puts more strain on the system.
- Efficiency – talk with our heating experts to understand the differences between the systems out there, and what will be most efficient for you in terms of both heating your pool and maintaining the temperatures you want.
- Cost – Electric heaters are more expensive initially, but when maintained properly, will last you 10 to 15 years! Manufacturers recommend you perform annual maintenance on your electric heater. Doing so will extend the life of your heater and will protect your investment! You’ll also have less monthly recurring costs as compared to a gas heater, which saves you even more every month!
These three factors together are complicated and should be worked through with an expert to ensure you get the pool heater that is right for your expectations and finances.
Loose tube collectors:
- Provide room for contraction and expansion, which reduces the risk of leaks
- This also leaves room for tubes to separate; debris can become trapped between the collectors and the roof, reducing their protection against wind.
- Provide room for contraction and expansion, while providing maximum surface area
- The flutes found between each tube provide more surface area, thereby increasing the size to energy ratio with each panel. More surface area = more heat, which provide warmer pool temperatures during colder months.
The difference between these styles is what we like to call “gloves vs. mittens”. When you wear gloves, your fingers are separated, which provides more opportunity for body heat to escape. When you wear mittens, your fingers are kept together, which promotes more body heat, and leaves less room for body heat to evaporate or escape.
Loose tube and tube-and-web collectors work under the same premise. Loose tube collectors operate much like that of the glove. Loose tubes helped to address wind load, but energy escapes or evaporates between the tubes. Tube-and-web collectors act as mittens; each tube is connected to the flute (or webbing). This means the energy you collect is less likely to evaporate or escape and the system will be more effective at warming your pool.
- Earliest effort at polymer solar pool heating system.
- Thicker tube walls result in low efficiency
- Tube separations due to expansion and contraction
Lessons Learned – Square Tube
Early efforts at making solar pool heating collectors used a square tube design that was easy to manufacture but was subject to buckling and tube separations. Tube separations resulted from the designs inability to handle expansion and contraction.
- Solid sheet design does not provide wind relief during adverse weather conditions and can trap moisture under the collector.
- Tube separation results from expansion and contraction.
- Flat surface does not “track” the sun for best all-day performance.
- Round tubes and thinner walls meant higher efficiencies.
- Buckling and weakening due to expansion and contraction.
Lessons Learned – Round Tube
Round tubes connected together form a variation of the square tube design which does not provide wind relief during adverse weather conditions and can trap moisture under the collector.
- Due to the tubes being connected together the design is plagued with buckling from expansion and contraction which weakens the collector.
- Wind load strapping must be able to stretch to allow for buckling and warping. Stainless steel straps cannot be used.
- The indirect feed system restricts flow which reduces system efficiency and causes high back pressure on the pool equipment.
- The small feeder holes of the sub-plenum can become clogged.
- Separate tubes eliminate stress from expansion and contraction.
- Spaces between the tubes trap leaves and other debris between the collectors and roof, also results in decreased performance from wind.
Lessons Learned – Loose Tube or Separated Tube
Loose tubes provide a “trap” for organic debris under the collectors. Performance is lower because sunlight passes between the tubes. Also, any breeze passing through the loose tubes affects performance.
- Each 4ft wide collector is assembled from 146 individual components resulting in 286 separate connections.
- Lightweight plastic mounting hardware allows the collectors to shift on the mounting surface.
- The spaces between the tubes allow debris to become trapped under the collector.
- Due to the radiator like design, wind or a light breeze can lower the performance significantly.
- O-rings at each header connection can try out and leak due to expansion and contraction.
- Designed to handle extreme expansion and contraction while providing maximum solar collector surface area.
- Patented vented web system allows for strong winds and adverse weather conditions.
- Provides 12% more surface area than smooth tubes.
As previously mentioned, there are several factors that affect the generation of thermal energy:
- Surface area of the pool (length x width)
- Direction of your roof
- Shade the pool receives from other structures or landscaping
- Depth of the pool
If the roof of your home is positioned in the most optimal way for solar (south-southwest), congratulations! You’ll see the most optimal results from solar heating with little extra effort. If you are like many homeowners in Phoenix and your roof isn’t positioned exactly right additional effort will be required to boost panel efficiency. So why is the pitch of a solar panel important?
Imagine your roof with a flat panel lying on top. As the sun rises and shifts in the sky, the angle of the sun’s rays changes. This means the energy hits part of the panel, but “bounces” off as the sun’s position changes. This deflection of energy reduces the overall BTU performance.
Will it still work? Yes.
But could be it be more efficient? Absolutely!
For customers that desire an eco-friendly solution, but have roofs positioned outside of the optimal position, panels can be placed on a rack on the roof to provide the proper tilt necessary. By tilting the panel to the proper position, the panel is able to capture thermal energy with little loss from deflection.
Heating your pool with the sun isn’t a new fad… it’s been a widely used technology since the 1970’s! In fact, the original solar pool collectors were made out of copper. There are two types of solar collectors used in most applications today: loose tube and tube-and-web. Aqua Science is a Master Dealer for Aquatherm Industries. Aquatherm Industries has been a leader in solar pool heating since the 70’s, and was the first company to be awarded a patent for their one-piece polymer design. It is that innovation and continued research in the market that makes the EcoSun panel the best on the market.
Solar pool heating is the most cost-effective way to heat your pool, as it has an endless supply of free energy from the sun, has no monthly recurring costs, and has a low annual maintenance schedule. In review of annual and forecasted electricity and natural gas prices, it was found you could save nearly between $12,000 and $28,000 over a 15-year period by selecting a solar pool heating system over a natural gas heater or an electric heat pump. In addition, using thermal energy to heat your pool qualifies you for a tax credit through the State of Arizona*. You could reduce your tax debt by up to $1,000 just for heating your pool!
- Innovation and research
- Aquatherm Industries was the first company to test and be awarded a patent for their polymer solar collectors in the 1970’s. Over the years, Aquatherm Industries has redeveloped their design to find solutions to problems faced in various climates. The evolution from round, smooth tube collectors to the current tube-and-web collectors are an example of their innovation.
- Aquatherm products received the first-ever 1,000 BTU/ft2 performance rating, certified by the Florida Solar Energy Center (FSEC) in 1993. They broke their own record again in 2014 with an FSEC record of 1,100 BTU/ft2.
- The most tested and trusted—Aquatherm Industries meets or exceeds the criteria set by:
- Outstanding product and design
- Certification from the NSF ensures Aquatherm products only put warm water back into your pool! An NSF certification verifies Aquatherm products:
- Do not contribute excessive levels of contaminants
- Are durable in design and construction
- Are resistant to corrosion
- Patented solar collector design
- Aquatherm only uses a pre-compounded resin in its collectors. This ensures an even distribution of protective anti-oxidants like carbon-black, which naturally resists the effects of UV rays and prevents the collectors from fading over time.
- Each panel is created from one polymer mold to reduce the risk of water leaks. Less holes = less leaks
- Marine-grade stainless-steel and anodized structural aluminum brackets and clamps mean attachments last longer, and flex with the panels as they contract and expand.
- Certification from the NSF ensures Aquatherm products only put warm water back into your pool! An NSF certification verifies Aquatherm products:
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