Solar Pool Heating

Installing a solar pool heating system is a very effective way to save money and reduce your environmental impact. VREC offers sales, design, installation, and repair services for solar pool heating systems.  We have installed or serviced systems throughout Vancouver’s Lower Mainland, including Vancouver, Burnaby, Port Coquitlam, and South Surrey (Whiterock).  Our service area is throughout the Lower Mainland, including the nearby islands.

Please contact us, or call 778.869.8333, if you would like a free quote, have any questions, or would like further information.  To evaluate a potential project in terms of energy production and financial paybacks, please consider booking an assessment.

Sample VREC solar pool heating installation

Solar pool heating installation by VREC at a home in south Surrey.

How It Works

A valve is installed on the swimming pool lines to divert the pool water through solar pool panels, absorbing the heat from the sun and then re-entering the swimming pool.  A controller uses sensors to determine whether there is heat to be gained in the solar panels, and if not, it will bypass the solar loop.  It’s that simple and it works great.  Chances are, your neighbourhood has many solar swimming pool heaters already installed.

In Metro Vancouver, the total area of the collectors is usually sized to represent 75-100% of your swimming pool area, depending on the site’s environmental conditions (if a pool cover used, how much wind exposure, etc.).  VREC determines the ideal location of the panels to maximize the system’s energy production.  The panels used are unglazed (pictured below) and are ideal for summer systems.  If you use your pool year round, we will tailor the system for your use.

We have access to panel manufactures but our preferred solar pool panel technology is the HotSun Powerstrip.  The Powerstrip system is very robust, reliable, and maximizes the installation area and design flexibility.  The panels have one of the longest warranties in the business and are easily repairable in the highly unlikely event that they should be damaged (unlike polypropylene solar panels).  They are manufactured in BC’s Lower Mainland.

Powerstrip solar pool installation by VREC.

Powerstrip solar pool installation by VREC.

Detail of Powerstrip

Powerstrip panels are made of Geon, a flexible vinyl formulation.  The header tubes are made of Luran,  a styrene acrylonitrile copolymer.  This combination of materials offer more flexibility than rigid polypropylene panel and won’t degrade in pool chemicals like EPDM.

Saving Money and the Environment

The simple and basic design is why solar heated pool systems are so affordable.  They’ll also have a very large impact on your heating bill.  As any pool owner knows, heating a pool requires a lot of energy, so it makes sense to capture some of the sun’s abundant and free energy.  In addition to reducing your heating bill, there will be a significant reduction in your greenhouse gas emissions.  If you choose to get an assessment instead of just a quote, we provide you with a performance, financial, and environmental analysis of a proposed design.

Frequently Asked Questions - Solar Pool Heating

How much does it cost?

Many factors affect the complete price of an installed system. To provide an accurate quote we require that a site visit be performed to collect all the necessary information to evaluate the home’s potential and design and price the system. After a site visit we can either provide a free quote or estimate, or we also offer the service of performing an Assessment. The assessment report presents system performance and financial analysis for the potential project. An assessment costs start at $200. The assessment cost would be credited against the cost of installing your system if you choose VREC as your supplier and installer.

How do I determine if a system is worth it financially?

We offer a service to provide an assessment report for the various renewable energy technologies. The assessment will present the predicted system performance and provide financial analysis of the project. The assessment costs start at $200 and the amount will be credited against the cost of installing your system if you choose VREC as your supplier and installer.

How do I obtain a free quote?

If you you know what size system you are interested in we can provide a quote.  Please use  our Contact Us form or call us at 778.869.8333.

How well does it work in Vancouver?

The below curves represent a typical 16×32 inground pool with a little shade (25%) heated or not with an aged solar cover and a eight 4’x12′ solar collector system (75% of pool surface). It was assumed the cover would always be on the pool 20 hours a day and for 4 hours the cover would come off (for the 2 plots with covers) and moderate pool activity would occur. The graph was created by Hot Sun Industries using Enerpool solar simulation software.

Typical Vancouver solar pool performance

Typical Vancouver solar pool performance.

What is the typical total installed cost?

Solar pool installs typically range from $4,000-$11,000 depending on how large is the system, if a controller is installed (highly recommnended,) roof arrangement, how much plumbing is required, etc.

What is the energy payback of the solar pool panels?

It has been estimated that a 4’x12′ polypropylene solar pool collector requires 12kg of natural gas and petroleum to fabricate. This gas and oil is equivalent to 120kWh of energy. The 4’x12′ solar pool collector should produce 120kWh of energy is less than TEN SUMMER DAYS.

What is the best type of solar thermal panel in terms of performance?

There are three main types of solar hot water panels: Evacuated tube, glazed flat panel, and unglazed flat panel. Each of these types of panels have different operating conditions where they have better efficiency than the others.
Our analysis shows that on average, in Vancouver’s environmental conditions for residential systems, unglazed panels work best for pool heating and glazed for domestic hot water heating. People commonly think that evacuated tubes are more efficient but that it only true when the inlet temperature is sufficiently higher than ambient temperature, or in some conditions when there is little solar energy available. To elucidate the different solar hot water panel efficiencies we will explain the metrics a bit and provide some examples. One should note however that the most important metric is not commonly efficiency but installed cost per energy savings collected.

Typical panel efficiency curves (based on gross panel area) are usually presented for one particular case of insolation (i.e. incoming radiation,) which is usually the case of full sun (1000W/m^2.) However the efficiencies strongly depend on the level of the incoming radiation:

Solar hot water panel efficiencies at full sun (1000W/m^2) and cloudy (200W/m^2)

Solar hot water panel efficiencies at full sun (1000W/m^2) and cloudy (200W/m^2)

One can look up the efficiency of most solar hot water panel manufacturers at http://www.solar-rating.org. As the efficiency is a function of inlet and ambient temperatures and incident radiation, it’s better if we compare the performance using a contour plot. The contour plots of the efficiencies for the three types of panels are shown below:

Efficiencies contours for the three main types of solar hot water collectors

Efficiencies contours for the three main types of solar hot water collectors

In order to compare two types of collectors it is better to consider the difference between their efficiencies, i.e. Collector A efficiency minus Collector B efficiency. Let us first compare Evacuated Tube and Glazed Flat Panel collectors.

Comparison of efficiencies between glazed flat-panel and evacuated tube collectors.

Comparison of efficiencies between glazed flat-panel and evacuated tube collectors. Solid line represents the efficiency cross-over. Positive values indicate percent efficiency that glazed flat-panel is better than evacuated tubes, and negative values vice versa.

In full sun conditions we see that glazed flat panel perform more efficiently than evacuated tubes. This is true up until the Inlet-Ambient temperature reaches 70C. In the summer an average ambient temperature is roughly 22C. This would mean the bottom of the solar storage tank would have to be greater 92C for evacuated tubes to perform better than glazed flat-panel collectors; a very unlikely scenario. In the winter an average ambient temperature is roughly 6C. This would mean the bottom of the solar storage tank would have to be greater 76C for evacuated tubes to perform better than glazed flat-panel collectors; again an unlikely scenario. One can clearly see that when the solar energy is highest and most abundant glazed flat-panel collector perform more efficiently than evacuated tubes.

Glazed flat-panel and evacuated tube efficiencies in full sun and cloudy conditions.

Glazed flat-panel and evacuated tube efficiencies in full sun and cloudy conditions.

In cloudy conditions we see that glazed flat-panel is more efficient than evacuated tubes up until the Inlet-Ambient Temperature is 20C. Using the same summer average ambient temperatures of 22C would mean the bottom of the solar storage tank would have to be greater 42C for evacuated tubes to perform better than glazed flat-panel collectors. With a winter an average ambient temperature of roughly 6C, the bottom of the solar storage tank would have to be greater 26C for evacuated tubes to perform better than glazed flat-panel collectors. One should also keep in mind that there is typically 1/5th the amount of solar energy available when it’s cloudy and that the winter days are shorter than the summer days. If one compares on a annual basis, flat panel collectors perform better than evacuated tubes for typical residential applications.

Let us now compare Glazed vs Unglazed flat-panel collectors.

Glazed versus unglazed flat panel efficiencies.

Glazed versus unglazed flat panel efficiencies. The solid line represents the efficiency cross-over. Positive values indicate higher efficiencies for glazed panels and negative values indicate higher efficiencies for unglazed panels.

We can clearly see that the glazed flat panel performance better than unglazed once the Inlet-Ambient temperature is greater than roughly 8C. However if we consider heating a swimming pool in the summer the inlet temperature from the pool might be 15-25C and the ambient temperature might also be 20C. In that particular case we see that the unglazed panel would be the most efficient panel. This might also be the case if for large commercial systems with very large water storage tanks. Once the ambient temperature drops to below roughly 8C from the pool temperature the glazed flat panel performs better; common in the off-summer seasons.

Finally, let’s consider evacuated tubes versus unglazed flat-panel collectors (“high-tech” versus the “low-tech”.)

Evacuated tube versus unglazed flat panel efficiencies.

Evacuated tube versus unglazed flat panel efficiencies. The solid line represents the efficiency cross-over. Positive values indicate higher efficiencies for evacuated tube panels and negative values indicate higher efficiencies for unglazed panels.

The surprising result shown is that in full sun conditions the “low-tech” unglazed panel performs more efficiently than evacuated tubes until the Inlet-Ambient temperature reaches roughly 25C. So for example, in summer if one considers a ambient temperature of 22C, the temperature of the bottom of the tank would have to reach 47C before evacuated tube panels performed more efficiently in full sun!

Why should I install a solar thermal system when gas is so cheap?

There are many reason why someone should consider installing a solar thermal system even though gas prices are currently low:

1) The amount paid for the system is equity in your house. If you should sell your home at some point in the future, and the system was maintained, you are likely to completely recover that equity (perhaps a little less or even a lot more.)

2) Increase your immunity to fluctuating energy costs. As energy costs inevitably fluctuate their impacts on your bottom line will be such smaller as you purchase less from utilities.

3) A major factor contributing to low natural gas prices is the non-conventional gas extraction method of hydraulic fracturing (fracking.) This has caused a large increase in the supply of natural gas and hence the lower prices. However the repercussions of fracking are slowly coming to light. In addition to causing earthquakes, and potentially contaminating water tables, fracking significantly contributes to greenhouse gas (GHG) emissions. Although natural gas releases less GHG emissions when burned as compared to coal and diesel, it has the highest GHG contributions if one considers the GHG emissions from extraction to consumption. These results were recently analyzed and published* based on considering a 20-year time frame for GHG equivalency since methane (a major contributor of global climate change and significantly released in fracking) has a 12 year lifetime.

*www.springerlink.com/content/e384226wr4160653/fulltext.pdf

4) Your helping the local economy and promoting green jobs.

5) If your solar thermal system is for a heated pool, you would effectively pay for the system over the next 4-8 years whether you get one or not. You can invest today and enjoy monthly savings and increase home equity, or you can pay the utility company every month.

6) Money saved from the system is effectively non-taxable income, depending on your tax bracket.

7) The planet’s ecosystem (including us) urgently requires humans to use solar technologies.

The list could go on…

How well can the system be expected to perform?

Performance of solar pool heating system depends on numerous factors, including panel orientation, whether a controller is used, shading on both the panels and pool, in the pool indoor or outdoor, wind exposure on both the pool and the panels, sizing, whether a cover is used, and of course the weather. That said, here are some general rules of thumb:

-The system typically take 3-5 days to reach their maximum pool temperature and maintain that temperature.
-Solar pool heating systems typically heat pools 8°C degree warmer than non-solar pool temperatures. By adding a pool cover, the pool can be heated 10°C-14°C higher that normal non-solar pool temperatures.
-The system should maintain that temperature increase based on average local weather conditions.
-A rough rule of thumb for comfort is to expect the solar pool heating system to allow you to enjoy swimming in the pool as long as the weather conditions don’t require wearing a sweater or coat. After which you are going to need a removable pool blanket and backup heater.

Of course, if the system is undersized (for example, a large pool with limited roof space, or budget constraints) the system will underperform. It will still efficiently collect energy and be cost effective, it will just underperform giving the sense that it’s not working well. The common rule of thumb for sizing is you will get a 1.5°C temperature increase compared to an unheated pool, from each 20% of the pool surface area that you put up in solar collectors.

What maintenance is required for solar pool heating systems?

Solar pool heating systems require little or no maintenance since there are no burners and only one moving part (the actuator on the diverter valve.) It is worthwhile to note that gas heater or heat pumps require more maintenance and normally last 1/3 as long as solar pool heating systems.

The system will have to be “winterized” and then re-activated in the spring. “Winterization” consists mainly of deactivating the solar on the controller and draining the solar piping lines.

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