Solar Southwest Florida

NOTE: See UPDATE at the bottom of this post.

Southwest Florida is starting to see all Lamar Advertising’s Billboards getting solar panel upgrades. My frustration level with this project is quite high already, first because I believe it was ill-conceived greenwashing, but also because it was poorly implemented. Here is a picture of a billboard in Fort Myers (which thankfully does not host Fafco Solar’s advertisement). Can you spot anything wrong?

Lamar Advertising Solar Billboard in Fort Myers on US41

Lamar used cookie-cutter prefabricated steel racks on their billboards. It would have been far more efficient to install all of these 12 solar panels on a single rack system, purpose-built for the billboard. But that is not the main problem here.

This system was installed by an electrician, whose name I will not mention. Electricians are authorized by Florida Statute to install solar electric systems. That does not make them experts, and here is a prime example. Still looking for the reason that this was done wrong?

A rack mounted solar array at optimal tilt and orientation has all solar panels facing the same direction.

There is only one ideal tilt angle and compass orientation for grid-connected solar photovoltaic systems in Southwest Florida. This tilt angle and orientation will harness the maximum amount of solar energy over the course of a year. Unless there are other cost, aesthetic, or technical reasons for an alternate orientation, solar panels should always be installed in manner that maximizes solar output. All six of the solar arrays are installed with different tilt angles and different compass directions. Although they are generally pointing south, and at a reasonable tilt angle, there is no physical constraint that would cause someone to design the system this way. Plus, it looks terrible.

The optimum tilt and orientation for solar modules can be found using publicly available resources that use a long history of local weather and solar radiation. It’s no secret where to find this information. The National Renewable Energy Labs is the preeminent source used in the U.S. to help solar installers maximize performance under given circumstances.

I would love to give Lamar and the installer the benefit of the doubt, thinking that this would be a test system to see what orientation works out best. After all, each of the six arrays features it’s own microinverter (the now obsolete Enphase D380). It would be easy to monitor each array to determine which produces the most energy over time. However, I can’t imagine this was the intention. I believe it is just a sloppy installation, bordering on complete incompetence.

The lesson: hire a solar professional, preferably someone local.

UPDATE February 29, 2012:

I have been having a lively discussion with Lamar’s Director of Sustainability and Product Research both in the comments below and by email. I am happy to report that the solar panels were askew in the picture above at the time of an upgrade to a digital billboard. It certainly makes sense that more solar capacity is present on this billboard than others, as the electrical draw will by significantly greater. I’m not sure how “sustainable” it is to use an electronic billboard, but it does look great and at least it is powered in part by solar energy.

It’s clear to me now that Lamar does take this project very seriously. After all, just having a Director of Sustainability shows significant commitment. We have a legitimate and passionate disagreement about how the money was spent on this project, and that’s fine with me. My position is borne out of financial reason. His position is that I am being short-sighted.

To be clear, I acknowledge that Lamar is vigorously and sincerely trying to encourage people to use solar energy, and that they are dedicated to a prominent sustainability program. I also appreciate the Director of Sustainability’s passion in defending the program.

There’s no perfect way to spend money to encourage people to “go solar.” Case in point is FPL’s $15.5M per year funding of its solar rebate program. Of this money, $5.6M was allocated to residential solar electric projects in the first round of financing for 2011, resulting in 2.8 megawatts of solar electric capacity (estimated based on the $2/w rebate amount). That’s a much better bang-for-the-buck than Lamar got with it’s spending to encourage solar energy. By the way – the funds for the rebate were exhausted in about 15 minutes after the rebate windows was opened. But, there have been negative consequences of the program. Primarily, the funding strategy limits the number of  ”lucky winners” in a very short window and discourages adoption of solar energy by those that cannot access a rebate because of the perception that solar energy needs rebates to be viable.

I have to ask – how much solar capacity has been installed in Florida as a result of the $2.5M of Federal grant money and $10.0M investment made by Lamar? Unfortunately, unlike the FPL rebate program, Lamar’s advertising campaign does not have people banging down the doors of solar dealers in Florida. I should probably be saying “thank you” for the free advertising, but I still contend that it’s solar done wrong.

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’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

I am seeing more interest recently from Southwest Florida Condominiums that want to install solar pool heating systems. The cost of operating electric heat pumps or gas heaters for condo pools is astronomical, especially this time of year. Condo boards are realizing that a large expense contributing to quarterly condo fees is the heating of their pool.

Artistic Rendering of a Bonita Springs Condominium. Condominiums are Perfect Cadidates for Solar Pool Heating.

In addition, typical Southwest Florida condos are busier this time of year as seasonal residents and renters are occupying a large percentage of condo units and warm pools are in high demand. During cold snaps, electric heat pumps are unable to keep pools at the desired temperature, and gas heat pumps consume huge amounts of fuel to maintain the set temperature.

While there is an upfront cost with solar pool heating systems, it is typically no more than the cost of electric heat pumps. If the condominium is in a position to purchase solar pool heating, it can dramatically reduce pool operating costs, and those savings can be returned to the residents through lower dues. While auxiliary heat pumps or gas heaters are typically required to maintain the desired temperature for swimming 365 days a year, the cost of operating them and their longevity is greatly increased.

While it is a bit harder to convince a whole condo board or the majority of condo residents to go solar, when the prospects of great savings are presented without sacrificing any luxury, the choice to pursue a solar pool heating system is typically made. Typical mounting locations are the pool equipment building, a ground rack system, or the closest condo building with an appropriately oriented roof.

Since condo pools are generally larger than a typical residential pool, a substantial amount of roof space is often required. Remotely located panels often require a little trenching to get plumbing lines from the pump location to the system. In most cases, the existing pump equipment is adequate for solar pool heating, but in some cases a booster pump is necessary. An automatic solar pool heating controller is essentially a required upgrade because of the way that commercial pools need to circulate water 24 hours a day. Manually operated pool solar systems are not advisable for condominiums.

Whether your condo association is looking for a complete heating system or just to cut down outrageous heating bills, solar pool heating is a great option for condo community pools.

Early morning dew covers PV panels at Naples Botanical Gardens

Fafco Solar has completed the FGCU Naples Botanical Garden photovoltaic system installation. I am particularly proud of this system and the expert installers that did the heavy lifting. The system includes 164 SolarWorld 245 watt solar photovoltaic modules, 164 Enphase M215 microinverters, a Unirac SolarMount mounting system, and S-5! Clamp attachments.

Because of the existing electrical system at the facility, the photovoltaic system is divided into two sub-arrays backfeeding power into two 208V 3-Phase electrical distribution panels. Commercial 3-Phase installations are always interesting from a design standpoint because typically we are dealing with various existing transformers and often generator backup systems.

Workers Install PV Module

It was truly a pleasure working with the Naples Botanical Garden staff and Manhattan Kraft Construction on this project. The weather cooperated for the most part. The job went very smoothly, finishing about a week ahead of my expectations.

This job is a model for future PV construction projects. We look forward to the next big PV job as we move on to a large multi-tenant solar water heating job in Fort Myers.