Solar Southwest Florida

FAFCO Collector Layout Strategies

It has long been the basis of solar pool heat design to have an opposite end feed and return. In fact, it’s published in several books and manuals about solar pool heating. This is not the case with FAFCO solar pool heating panels, which can be installed with same side feed and return!

Opposite end feed and return simply means that the plumbing that brings up to the solar panels and connects to the lower header is connected at the opposite end of the bank of solar panels from where the plumbing connects to the return line to the pool. Conceptually, this is done to ensure that all solar panels get filled with water and the flow rate is even throughout the bank of panels.

The FAFCO system is a bit different, mainly because FAFCO’s panels have a 2 inch header, 78% more volume than the competition’s 1-1/2″ header, and a subheader that helps to balance the flow among all panels in a solar array/bank. This ensures that all panels have the same flow rate.

It is important to note that you cannot exceed 12 panels in a row with same side feed and return (see Figure 4). Also, split feed and multi-bank systems with varying heights must use opposite end feed and return lines (see Figure 5). The FAFCO manual is very clear about the layouts that are permitted.

Same Side Feed Return Example for Solar Pool Heat Plumbing

SunTouch Controller Installation

I finally got around to installing my Pentair SunTouch Solar Controller at my Fort Myers home. I don’t have solar pool heat (yet), so I have been procrastinating. Why install a SunTouch without a solar pool heating system? Because it does so much more than just control a solar valve!

The SunTouch is made to work with an actuator to automatically turn solar pool heating on and off based on the desired temperature and the available heat on the roof.

Here are several great reasons to install a SunTouch Controller:

• It’s a great compliment to my Pentair Variable Speed Pump (VS-3050). The SunTouch takes over the control of the pump functions and speeds, allowing you to program various speeds for things like water features, automatic cleaners, solar, and auxiliary heaters.
• It will control a heat pump or gas heater with or without solar pool heat. I happen to have a heat pump (I know, not good, but it came with the house).
• I can control my landscape lighting (LED, of course) with one of the auxiliary relays and put the transformer on a timer.
• I can control the pool lights and program run times.
• With the QuickTouch remote, I can activate features from the handy remote control. While I have the landscape lighting and pool lights on programmed schedules, I can manually turn them on from the remote. I can also manually force the pump on at various speeds.

QuickTouch Remote and Receiver

Because my pool and landscape lighting were on the same circuit, and because I still have old energy-hog incandescent pool lights (2 x 300W), I am excited to be able to run the landscape lighting independently now. For added security, and because they use virtually no energy, I set my landscape lights to run all night – something I wasn’t able to afford with the pool lights. One day I’ll spring for the LED pool light upgrade.

I set out to do this project yesterday and it took a little longer than expected with all of the auxiliary features I wanted to control. I also had to rewire the lighting transformers because the pool and landscape lighting were on the same circuit. I went ahead and installed the water and solar sensors so I’ll be ready to go when I add solar pool heat this spring. Finally, I took the opportunity to wire a GFCI outlet next to the SunTouch for extra convenience when running my electric trimmer.

The initial programming of the SunTouch is a bit complex, but fortunately my experience at Fafco Solar had me prepared for this challenge. The menu operation is not very intuitive, but once you understand it the button functions, it all makes sense. The SunTouch documentation on the variable speed pump programming is a bit confusing, but once you read the pump manual itself, it all comes together. I was able to easily configure my remote control to control my pump and lights. The QuickTouch remote connection is also

I didn’t connect the heat pump relay, partly because I ran out of time, but after thinking about it I would rather not have it on a controller. I want to feel the pain every time I manually turn it on, and remember how much that thing costs to run! I can see the benefit of connecting it for people who have pool/spa combinations to fully automate spa heating.

Overall, I am very impressed with the system, and I look forward to installing my solar pool heating system soon!

My Pool Equipment with SunTouch Solar Controller Installed

When you’ve got it all, things can get pretty complicated. Solar pool heat plumbing with a heat pump and a spa can result in a spaghetti factory of plumbing at your pool equipment. Pictured below is an Estero, FL system containing:

• Solar Pool Heat
• Auxiliary Electric Heat Pump
• Pool and Spa with Blower Combination
• Cartridge Filter
• Pool Drain Valve
• Aqualink automatic controller
• Landscape lighting

Complex Solar Pool Heat Plumbing

The good news is that the automatic controller does just about everything you can expect to control the pool and spa heating automatically. The only user intervention required is to set desired temperatures and priorities for heating sources. The owner may also want to manually adjust the spill-over waterfall from the spa to the pool.

Note: Fafco Solar added the solar pool heat to the existing system installed by others and connected the solar pool heat to the Aqualink controller.

Fafco Revolution Solar Water Heating System with 48 square feet collector area (3 panels @ 2'x8')

In Southwest Florida’s upscale communities, you find homes with lots of small, broken up, hip roof surfaces. Roof layouts can be very challenging for solar energy systems, especially because we are targeting the south facing roofs to maximize performance.

Solar water heating systems come in various sizes, but are all generally rectangular in shape. The Fafco Revolution system is flexible, offering 2′ wide panels in lengths of 8′ and 12′. On almost any roof we can find a suitable location for a solar water heating (SDHW) system.

Some roofs are simply not suitable for larger solar pool heating panels, but can accommodate solar water heating or solar photovoltaic systems. While installation can be more challenging on smaller roofs, it’s absolutely possible to “go solar” no matter how your roof is constructed. All I need is your address, and I can look at aerial imagery to determine what will fit!

Some complex hip roofs have limited options for solar energy products and present challenges to solar contractors.

What does the Acronym SPH stand for?

SPH = Solar Pool Heat

a.k.a Solar Pool Heat

SPH is an acronym for Solar Pool Heat or Solar Pool Heating systems. SPH systems use polymer solar panels to heat pool water. SPH systems use solar thermal technology and do not produce electricity. Solar Pool Heating systems circulate pool water through the solar panels to transfer solar radiation to the pool, increasing water temperatures.

SPH Panels - Solar Pool Heating System

If you have a solar pool heating system, your dealer may mention the manifold. This is just a set of valves that control the flow of water in your solar pool heating system. The function of the solar pool heat manifold is to turn you solar on or off by bypassing the solar panels when necessary. Your manifold may or may not include isolation valves to isolate the solar panels in the event that the system must be serviced.

Let’s take a look at an example manifold. The one pictured below includes two high quality Jandy brand isolation valves, a Jandy brand bypass valve, and a motorized actuator that is controlled by a pool automation system, in this case, an Aqualink system. Note that the bypass valve is also known as a diverter valve, a 3-way valve, or generically as a Jandy valve, which can be confusing.

Solar Pool Heat Manifold (Click for Larger Image)

Your solar pool heat manifold may look significantly different from this, but the concept is the same. We need to be able to control whether the water from the pool pump goes up to the solar panels, or bypasses the solar panels and returns directly to the pool. In the current configuration, the solar pool heating system is on, and water is able to flow through the panels on the roof. The red “X” is the bypass plumbing. When the bypass valve is in the other position, the solar panels are bypassed, and the water flows directly back to the pool.

The isolation valves should NEVER be closed when the bypass valve is in the solar-on position. This “dead-heads” the pump, meaning that the pump is running, but there is nowhere for the water to go.

It should be noted that the bypass valve is typically a “non-positive” valve. That means that it does not actually stop all of the water from going one way or the other. This is important so the water in the panels can drain back into the pool when the solar pool heating system is off. Draining water from the panels helps prevent freeze damage to the panels. This can be accomplished several ways, which are beyond the scope of this article, but note that it may not be readily apparent how your valve is made to be non-positive. Some systems, due to plumbing configurations, are manually draining. They must be drained manually or using a drain valve if installed.

Some common parts of the pool heating system plumbing are not shown here, like check valves that only allow water to flow in one direction. I’ll get to that concept in another article!

There are several ways to make a solar pool heat manifold, and some features may not be present in yours. If you have a question about your manifold, take a picture and email it to me at jason (at) facosolar.com and I can help you make sense of it!

What does the Acronym PV stand for?

PV = Photovoltaic

a.k.a Solar Electric Panel, Solar Photovoltaic Panel

PV is the term used in the solar industry to shorten the tongue-twisting word Photovoltaic, which describes a method of generating electrical power by converting solar radiation into direct current electricity using semiconductors that exhibit the photovoltaic effect (Photovoltaics, 2012). The photovoltaic effect is how electricity (voltage and current) is generated from light. The term is often used in the context of PV Panels, PV Modules, or PV Systems.

PV Panels

References

“Photovoltaics.” Wikipedia, The Free Encyclopedia. Wikimedia Foundation, Inc. 12 Jan 2012. Web. 22 Jan 2012.

S-5! Clamp

After years of seemingly nothing but tile roofs being installed in Southwest Florida, metal roofs are getting popular again. The longevity, durability, and energy efficiency of metal roofs are great selling points, and they look great, coming in many profiles and colors.

The metal roof is known for protecting roofs against leaks, and minimizing penetrations is very important for roof warranties and customer peace of mind. There is an aluminum clamp called an S-5! that attaches solar panels to the standing seam of metal roofs without penetrating the metal.

The strength of these clamps is amazing. Test results on many roof profiles indicate that they can withstand wind uplift exceeding 1,000 pounds per clamp in many cases. Depending on the wind loads in our particular solar panel design, enough clamps  can be used to ensure a safe and effective solar panel attachment. With required design wind speeds in Southwest Florida ranging from 120 mps – 150 mph, wind uplift is an important design factor.

Of course, it is important that the metal roof is installed properly, and meets the requirements of the panels that will be mounted on them. If the roof panels are installed to meet the 2007 Florida Building Code, it is almost certain that there will be no issue with using S-5! clamps. Older installations should be evaluated on a case-by-case basis.

Typical S-5 Attachment Design

The clamp comes in a variety of shapes and sizes to meet the requirements for just about every metal seam profile. There is even a clamp that allows you to attach a solar electric module directly to the metal seams without the use of aluminum rails. However, this clamp is incompatible with new microinverter technology because microinverters must have something on which to mount.

While the S-5! clamps do not work on some metal roofs, like those with 5V or sinusoidal profiles (corrugated metal roofs), the standing seam metal roof profile is quickly becoming popular around the area on both homes and businesses. If you have a metal roof and don’t want to penetrate it to attach solar panels, take a look at S-5! clamps!

What does the Acronym SDHW stand for?

SDHW = Solar Domestic Hot Water

a.k.a Solar Water Heating, Solar Water Panels

SDHW is the term used in the solar industry to describe solar water heating collectors (panels) or systems. Several types of SDHW exist, including flat plat collectors made of copper heat exchangers in aluminum and glass enclosures, heat pipe collectors with copper pipe enclosed in evacuated (vacuum) glass tubes, and polymer collectors like the Fafco Revolution SDHW system.

Fafco Revolution Polymer Collector SDHW System

Flat Plate SDHW Panel

Solar water heating systems obviously heat water only during the day when solar radiation is hitting the solar collector. You might realize why it is important for Solar Water Heating Systems to store water, but to what extent should this be considered?

Source: Fairey, P., & Parker, D. (2004). A review of hot water draw profiles used in performance analysis of residential domestic hot water systems. Florida Solar Energy Center. Retrieved from http://www.fsec.ucf.edu/en/publications/pdf/FSEC-RR-56-04.pdf

In North America, most hot water is consumed in the morning, presumably for personal hygiene. The second most water is consumed in the evening, as people clean the kitchen and prepare for bed. This creates a scenario where hot water is required at times when the most energy is not available. Much of the water stored in a tank may be exhausted in the evening with no solar resource available to heat water for the morning requirements!

The solution to this is to provide adequate storage of hot water so that there is enough solar heated water available when needed. On the other hand, providing too much storage becomes economically unreasonable, and in many homes, is impractical because of the space available. Here in Southwest Florida, water tanks are typically in a small closet or garage where storage space is at a premium.

The rule of thumb given to us by the National Renewable Energy Labs for solar water heating systems in residences is to provide at least 1.5 gallons of storage for each square foot of solar collector area (Urban, 2011). (Note: this applies to typical glass-copper flat plate collectors, not polymer collectors like the Fafco Revolution system). A typical 40 square foot solar collector would require a minimum 60 gallon tank. An 80 gallon tank is generally recommended.

However, this analysis is based on averages, and your water usage may not be average! For example, we have a lot of retirees in Florida who like to play golf in the morning and shower when returning from the course in the mid-day. Meals are often eaten earlier than in working families. Some families only shower in the mornings or evenings and some families do not cook often. The point is, if yours does not fit the typical or average U.S. household, your hot water demand might be vastly different and should be discussed with your solar dealer prior to installing a solar water heating system.

Possibly even more complex is hot water storage for commercial applications. Restaurants, offices, and hotels all have vastly different water heating needs. For example, in a recent study, “Monitoring And Modeling Hot Water Consumption In Hotels For Solar Thermal Water Heating System Optimization,” (Urban, 2011) it was determined that the optimum storage capacity for hotels was between 1/2 and 8 gallons of storage per square foot of collector area. Four gallons would be a good rule of thumb, but the author cautions that an analysis should be done on a case by case basis. Unfortunately, a full demand analysis is typically economically impractical, and estimating by solar professionals is the norm.

Typical Solar Water Heating Collector, 40 sq ft.

In addition to these factors, decisions need to be made whether to provide a dedicated solar storage tank that preheats water, or simply heat the lower half of an existing or new electric water tank. This is particularly the case in residential applications. Usually an adequately sized tank can be retrofit with a solar panel, and the bottom electric element is disconnected. The top electric element remains connected to provide a backup to the solar heated water. In the case of a dual tank configuration, both elements remain connected on the electric water tank, but the incoming preheated water from the solar tank results in greatly reduced electric heating costs.

Ideally a demand analysis would be performed on a case-by-case basis, but the cost of such an analysis would unreasonably reduce the savings and increase the payback period for solar water heating systems, especially in residential situations. As solar professionals, we are required to make judgment calls after making assumptions about and listening to our customers. Using generally accepted rules-of-thumb, we can supply economical systems that are sure to save homeowners significantly on water heating costs.

References

Urban, Eric J. “MONITORING AND MODELING HOT WATER CONSUMPTION IN HOTELS FOR SOLAR THERMAL WATER HEATING SYSTEM OPTIMIZATION.” (2011): 28+. Web.

I had a little fun creating this video from an older post about how you need different solar panels for different tasks. One solar panel can’t do it all – at least, not as effectively as panels designed for a specific purpose. Let me know what you think of this animated video.

No Flash Player? View Here: http://www.youtube.com/v/GAA3BYpdPww

I’m toying with the idea of creating some how-to videos using XtraNormal… just for fun.

One great feature of the Pentair Intelliflo Variable Speed Pump is the self-priming option. The pump is sent from the factory with this option on. However, because the pump runs at maximum power at start up, it is very loud and some people are bothered by it. If your pump is located outside a bedroom or office, you may be annoyed by the sound when the pump starts.

My pump never loses prime, so I am not concerned with the priming feature. When I clean my filter basket I may need to prime the pump again, but that is easy to accomplish by selecting one of the higher speeds manually for a moment when I first start the pump. I prefer to turn the priming feature off to avoid the noise. Here’s a video that shows you how to turn off (and on) the priming feature on the Pentair Intelliflo Variable Speed Pump.

(No Flash Player? Download here: Pentair Variable Speed Pump Priming)

With the pump off, the buttons to press to toggle priming on or off are:

Menu | Down| Down| Down| Down | Select | Select | Down | Enter

Rather than turning auto-priming off, you can also change the priming sensitivity. The pump will detect whether priming is necessary, and theoretically will not go into auto-priming mode if it detects that the pump is primed. However, I have not had good success adjusting sensitivity to reduce unwanted priming. I find it’s better to just turn off the feature.

WARNING: If you turn off the priming feature and your pump detects that it is not primed, it will go into error mode to protect the pump. This is a great feature to save your pump from damage, but it must be reset manually. I have never experienced a problem with this, but if your pump loses prime frequently, it could be a problem. Then again, if your pump loses prime frequently, you should determine the cause and fix it!

Fafco Solar’s next solar water heating project for the Southwest Florida Affordable Housing Choice Foundation is in Cape Coral at the Coconut Apartments. Each of the two multi-tenant buildings have four dwelling units with three 2′x8′ solar water heating collectors per unit. Installation of the solar panels just started, and here’s the day one picture of the first building. Like the Broadway Apartments project, the panels are mounted on rails attached to the standing seam metal roof with non-penetrating S-5 clamps.

This construction site is just a stone’s throw from the Fafco Solar office and warehouse, making this one of the most convenient solar water heating jobs we’ve worked on!

Solar Panels on South Roof

Can you spot anything wrong with this photo?

I’m at the ribbon cutting ceremony for the Broadway Apartments affordable housing project where we have 40 solar water heating systems installed. This is the largest polymer solar collector water heating project in Florida!

Solar water heating will reduce the electric bills for residents of the two-building multi-tenant property.

The goal of the project is to provide affordable housing that features low utility bills in a LEED Platinum facility. The solar water heating systems were one part of the LEED criteria that allowed the Broadway Apartments to achieve Platinum status.

The Southwest Florida Affordable Housing Choice Foundation reports that previous residents are already asking for applications to rent units. The property is deed restricted so rents will remain low for the long-term. The community is actively seeking residents for annual leases available now.

Congratulations to The Foundation, Chris-Tel Construction, and all of the project partners!

UPDATE: Here is the Fort Myers News-Press story on the event: http://www.news-press.com/article/20120120/GREEN/301200046/Low-income-housing-in-Fort-Myers-adds-green-efficiency

Fafco Solar has installed lots of Canadian Solar photovoltaic modules, and now the company is improving its already great warranty. New solar panel buyers will get a 10 year workmanship warranty (up from 6) and a 25 year linear power guarantee.

Many module manufacturers offer a 10 year 80% power output guarantee and 25 year 90% guarantee. Canadian Solar was on par with this standard, but the linear warranty guarantees that you will now have at least 97% of rated output after one year, with only 0.7% degradation each year after that. This is a great upgrade that more and more companies are offering as the reliability of photovoltaic modules is proven in the field.

Canadian Solar takes the warranty one step further and has purchased insurance from an AM Best rated insurer to guarantee that the warranty will remain in place even if the company does not.

Since Canadian Solar is currently right in the sweet spot for “dollars-per-watt” efficiency, this new warranty makes the brand a great buy at this time.

UPDATE: Paul Coughlin from groSolar sent me this Comparison of top module manufacturer warranties. It highlights Canadian Solar’s pioneering insurance coverage.

http://www.solarsouthwestflorida.com/wp-content/uploads/2012/01/PV-Module-Warranty-and-Warranty-Insurance-Comparisons-White-Paper-Sept.-2011.pdf