Welcome to the "Solar Pool Heating" web page
of
APEX Thermal Services

If you or your family or friends (or club or workplace)
are heating a pool with fossil fuels, please have them
call or contact APEX Thermal Services.  There is huge
money to be saved by installing solar pool heating
equipment.  It can work solo, or in conjunction with
existing heating equipment (if the pool MUST be at a
certain temperature).  This is often the case with
larger institutional pools.  Pool heating is VERY energy
intensive, more so than heating an entire home, so
the bills can be tremendous!  Residential pool
heating bills can easily add up to $600 or more per
month.  And that is conservatively based on fuel
costs before this most recent price spike!  I know that
I have absolutely no interest in those bills, or heating
a pool with that approach.  I also know that we can
help you reduce those costs considerably, using the
sun as your no-cost, tax-free energy source.

So, what does it take to heat your pool with the sun?
Well, there are some variables to the system design,
including how much shade or sun the pool gets, wind
conditions, and the size of the pool.  If you have an
indoor pool and wish to heat year round, you will
need to use either flat plate or evacuated tube
collectors (I recommend flat plate collectors).  For
outdoor pools and seasonal pool heating, the less
costly unglazed panels are the way to go.  

To somewhat simplify the solar array sizing approach,
most pools will typically need unglazed solar panel
surface area equal to about 75% to 100% of the
surface area of the pool itself.  The system pictured
to the right used nine 4' x 12' panels, that is 432
square feet.  Based on 75% of pool size, this system
would be satisfactory for most pools, up to about 576
square feet, or a pool about 18' x 32'.  

If a pool has a significant amount of shading, it would
be a candidate for closer to 100% collector area to
pool area ratio.

Unglazed solar pool heating panels are typically roof
or ground mounted.  In most cases, the existing pool
pump(s) are adequate to provide the lift of the
water to roof elevations.  However, that is not always
the case.  In any case, be prepared to upgrade to
the next size pump motor.  

Ground mounting of unglazed solar panels is an
attractive alternative to roof mounting, and also
lessens the possibility of having to upgrade the pool
pump.  Obviously, the property must have
adequate area for your array.

Some companies sell unglazed solar panels for
domestic water heating, as a alternative to more
expensive glazed or tubular collectors.  Though they
would perform well when it is warm, when the
outdoor temperatures turn cold, they would be
virtually useless.  If you are looking to only heat your
domestic water in the summer spring and fall,
unglazed panels may fit the bill.   

Solar pool heating systems are controlled with solar
pool heating controllers.  The controls are and
function similar to solar thermal controllers.  They are
typically contained in a weather-proof/
weather-resistant box, appropriate for mounting in
outdoor locations.

Indoor pools provide an interesting situation.  If the
pool owner is interested in year-round solar pool
heating, you will need to use either glazed flat plate
or evacuated tube collectors.  In these systems, the
pool fluid will be pumped through one side of a heat
exchanger, not directly through the collectors.  The
solar fluid that is pumped through the panels and the
other side of the heat exchanger will likely have
antifreeze added.  They will probably also be
installing a fossil fuel system to provide heating for
days when the sun doesn't show up for work.

With solar pool heating systems that require
year-round heating, unglazed solar panels are not an
appropriate choice.  Basically, the required system is
a very large solar hot water system, using glazed or
tubular collectors, with the capacity and size to heat
a very large body of water.  Either a conventional or
pool heating controller would be able to provide
appropriate system control.

In the solar thermal heating system pictured to the
right, pool heating was a side benefit to this 6-panel
installation.  The customer was interested in solar hot
water, solar space heating for their basement, and
solar pool heating.  In this example, from a design
perspective, the collector surface area is much
smaller than optimum, in comparison to the size of
the pool.  However, that doesn't mean that the
system doesn't heat the pool.  The customer was OK
with a system that would take the chill off the pool,
when the sun's energy was available.  This system's
primary function is heating a 230 gallon tank in the
basement, used for domestic water preheating.  A
small fan coil unit is also attached to the solar tank
and is used for supplemental heating in the
basement.  

Remember, for any pool heating system to collect
solar energy from the collectors, the pool pump
needs to operate while the sun is shining.  Please
keep that in mind when programing the pool pump
timer.  A more sophisticated approach might be for
the solar pool controller to start the pool pump when
there is adequate energy to be collected.   Avoid
control settings that would result in a lot of pump
cycling.

Pool piping is typically done with PVC pipe.  Working
with PVC pipe is relatively easy, though layout must
be thought out before getting to far along.  
Basically, near the pool pump, a motorized diverter
valve and some additional piping and components
are  installed as well as the panels and connecting
piping.  When there is adequate energy in the
panels, the solar controller sends a signal to the
motorized diverter valve.  This valve either sends the
water on it's no-solar-available path, from the pump
directly into the pool, or to the solar pool heating
panels, and from the panels to the pool.  You can
feel the heat at the water inlets of the pool, but
considering the vast volume of the pool, it can take
some time to heat up, just like when you are burning
expensive fossil fuels.

Public pools, swim clubs, universities and hotels can
benefit greatly from this technology.  Often times,
they have temperature settings higher than that of
residential pools.  This means there is even more
savings potential.  Let's face it, the days of cheap
energy are behind us.  Even if we get teased with
lower fuel costs in the future, we should avoid taking
the bait.  Yes, making the most of an abundant and
free energy source takes an initial investment, but,
after that, it is all savings from there.

Why spend thousands of dollars per year heating
your pool?