A
recent
article in the March 2012 digital issue of
AQUA
Magazine highlights solar pool heating with heavy input from our industry-wise
Heliocol
solar pool heating staff. Kudos to Director of Marketing Tod Ellington, Vice
President Bob Zrallack, National Sales Manager Loren Zucconi and Senior Professional
Engineer Michael Studney for sharing their considerable solar industry
knowledge with AQUA Magazine readers.
Solar
Points, AQUA Magazine, March 2012
by
Eric Herman
Experienced pool and spa owners will
often complain that it simply costs too much to heat their water. Rising energy
prices result not only lighter billfolds but also shorter swimming seasons and
ultimately diminished use and enjoyment of their vessels. For those reasons and
more, solar water heating systems have remained a popular heating option, which
when installed properly can transform the frustration of obtaining warm water
into the joy of affordable luxury.
 |
| A recent article in AQUA Magazine outlining the benefits of solar pool heating systems. |
The notion of harnessing the sun’s
energy to serve our earthly needs in the form of a ready and renewable energy
source is hardly anything new. There’s an inescapable logic to utilizing the
inexhaustible source of energy that is our sun in favor of burning fossil fuel.
And as energy prices continue to rise,
the appeal of heating water for pools and spas in particular using the sun
becomes more and more enticing for many consumers who want to both save money
and extend their swimming season without their lips turning blue. And for those
concerned about “going green” it doesn’t hurt that solar heating leaves
virtually no carbon footprint.
That’s all been good news for solar manufacturers,
who currently report that even through the tough economic conditions of the
past four years, the market for solar heating, both on the residential and
commercial sides of the market, has remained steady and has even made inroads
in places they wouldn’t have expected. Even homeowners in areas such as the
upper Midwest and Northeastern U.S., regions considered less likely to turn to
solar to due their colder climates, have embraced solar heating.
Despite the ironclad logic behind
solar thermal heating systems, successfully applying the technology does
require hitting a handful of key technical concepts as well as governing client
expectations. Here are a few of the main issues that need to be addressed in
order for consumers to enjoy the limitless bounty of the sun’s free energy.
The good news is that all of these
points boil down to basic common sense and when presented to clients in the
right light, solar heating becomes more appealing and attainable.
Proper Installation
Those who install solar heating
systems must be part plumber, roofing contractor and electrician. That’s why manufacturers
strongly recommend that homeowners turn to qualified dealers to size and
install their systems and not take on the challenge themselves.
Hydraulic calculations, although not terribly
complex, need to be considered with issues such as pump sizing
relative to the flow requirements of
the solar panels, as well as resistance provided by vertical lift to the panel
locations. And the plumbing connections need to be properly installed to avoid leaks.
On the electrical side, solar systems require
connections to automated valves and heating control systems.
Again, although not complex by any stretch,
those connections require an understanding of basic electrical installation techniques
and hardware.
And finally, rooftop installations
require making small numbers of penetrations to secure panel-mounting hardware.
Proper use of sealants and flashing is therefore critical to avoid leaks.
For these basic reasons, solar pool heating
should not be viewed as a do-it-yourself proposition.
Performance Anxiety
As is true of most technologies,
consumers should be informed in clear and understandable terms what to
expect from their systems in terms of performance.
They need to first understand that solar
heating systems operate when the sun is out and therefore it’s necessary to
circulate their pool’s filtration systems during the day, as in the vast majority
of cases, the solar system will run off the primary circulation pump.
Consumers should be aware the solar
heating is most effective when viewed as a daily heat maintenance source. How
fast a system will raise water temperatures depends on the exposure to
the sun and the desired
temperature rise — which in pools will
typically top out at about 90 degrees. Depending on ambient temps and other
variables, solar heating systems may take two to three days or longer to generate
desired water temperatures.
A client who swims for exercise may only
want temperatures in the mid-70s and in a mild climate, a properly
sized solar heating system will bring the
water to the temperature in relatively short order, and evenly maintain
it over time. By contrast, a client
who wants temps in the high-80s and lives in a cooler climate can also achieve that,
but it will take longer to raise the temperature to the desired level.
Because solar heating systems are subject
to the weather, clients should be reminded of basic pool facts such
as the cooling effect of rainfall and
the required time needed to reheat the water. In most cases, clients are
surprised by what they can achieve in terms of heat rise and maintenance, so
long as they’ve been properly informed about the realistic limitations of their
systems.
Meets The Wallet,
Meets The Eye
When it comes to payback on
investment, solar systems consistently outperform expectations. The variables
impacting return on investment include
cost of heating in the area, the size of the pool, desired temperature and, of course,
prevailing climatic conditions.
Clients who have used fossil fuel to heat
their pools can easily calculate the savings — and the numbers are typically
impressive enough to motivate serious interest in obtaining a system. As a
general rule, manufacturers report that in the vast majority of situations, the
systems repay their initial costs within two years.
By contrast, perhaps the most vexing client
concern involves the appearance of the panels themselves.
Because they do consume significant surface
area and are typically installed on roofs, the panels are quite visible. Some
suppliers now offer panels in different colors that help blend with roof
material.
Beyond that, the message to consumers is
that most people come to see the panels in the way they see a satellite dish,
television antenna or even power lines. They simply become part of the accepted
scenery. And when the cost savings and increased enjoyment of the water is
factored in, the appearance of the panels becomes far more forgivable and even
potentially a point of pride.
Size And Exposure
Manufacturers size solar systems based
primarily on surface area of the water rather than volume, based largely on the
fact that approximately 70 percent of all heat loss in a body of water is due
to evaporation. It’s common for suppliers to recommend that the surface area of
the panels equate to 80 percent of the surface area of the water.
Again, depending on climate and desired
heat rise, the sizing may change, perhaps taking the size of the
panels up to 100 or 120 percent of
surface area. By contrast, there are situations, especially in warm climates, where systems can be sized as low as 50
percent of water’s surface area.
Because evaporation plays such a huge
role in heat loss, all solar heating professionals recommend the use
of some type of solid cover, whether a
floating solar cover or a solid safety cover. Simply preventing evaporative losses
using a cover will typically more than double overall system efficiency.
As a side note, when systems include fountain
elements or waterfalls, which can dramatically add to evaporative losses, many
installers and manufacturers will recommend upsizing the panels to compensate.
Exposure to the sun is essential, of course,
and in situations where adequate exposure is not possible, the
most staunch solar heating advocates will
admit that the systems may not be worth the cost and will most likely only lead to unsatisfied customers.
The rule of thumb here is simple. In
the Northern Hemisphere, solar heating panels should optimally be
mounted when facing within 45 degrees of
southern exposure. Otherwise they will only be in direct sunlight during the
summer months, when heating is less of a concern. East and west facing
exposures can still be effective, although they could require upsizing or
moderated client expectations for performance. Systems installed on flat roofs
are perfectly acceptable.
