-
Make sure you don't shade your solar
panels (or the collectors, but they are more shade tolerant)
-
The ideal ratio is 1.5 to 2
square feet of collector surface per gallon of storage.
Performance will suffer if you are far from this ratio.
-
When using an Aquastar heater in a
closed loop system, pay attention to the
size of your circulation pumps
- they need to provide enough flow to trigger the Aquastar to turn on.
Ideally the circulation pump should be on the feed side of the heater,
but that is not always practical.
-
Install the circulation pumps in the return side of the heating
loop. They will stay cooler and last longer.
-
In retrospect I would have used a
brazed flat plate type heat exchanger as they perform better and can be
easier to plumb in as well.
-
Ground all your collector and PV
frames. I lost 2 El-Sid solar powered circulation pumps to a
static discharge in the fall of 2003 (not an actual lightning strike).
The electronic driver circuits in the pumps fried. I then grounded everything to the service entry ground rod with 10 gauge
copper wire.
-
When re-pressurizing the inside
closed loop(s), make sure that the water is not warm (over 70F).
When the water cools your loop temperature will drop and bring the
system pressure down too. Closed loops tend to require at least
30psi to work reliably in my experience. Since my system is
isolated from household water pressure (40psi) - I use a fill pump that
can only achieve 16psi. I then augment that pressure by pumping
air into the expansion tank with a bicycle pump to get 30psi.
-
An interesting note. My first
year I only had the radiant slab installed and the return temperature
from the slab was about 70F. This became the default temperature
of the storage tank - without any solar contribution. Then I added
2 10 foot baseboard radiators on the 2nd floor. The return
temperature from this loop is 110F which raises the default temperature
of the storage tank. This significantly increases the system efficiency on
cloudy days since that heat is recovered and re-used.
-
Place
automatic air vents at the
highest points in each loop. For the outside loop use a manual key
vent - the automatic ones may not survive weather extremes. Check
the vents yearly for leaks and to release air.
-
Insulate your collector plumbing -
especially if you have long exterior runs. Use Rubitex black
rubber boiler insulation on the collector loop. Domestic foam pipe
insulation will melt at collector temperatures! Been there, done
that!
-
Install lots of temperature gauges.
Before and after the collectors. Before and after the storage
tank. Before and after the floor loop(s). This really helps to
diagnose problems.
-
Install lots of unions in the
plumbing so that you can readily unscrew them to remove plumbing sections for
repair or upgrades.
-
Install lots of ball valves so you
can close off sections of the system for maintenance. This saves
you from having to drain the whole system just to replace a faulty gauge
or spigot seal.
-
Use a fiberglass mix in your radiant floor
concrete if it will see heavy use, or if it will be less than 4" thick,
this adds a lot of strength.
-
In snowy climates pay attention to
solar panel and collector location so that you can clear snow off
relatively easily. In northern locations the bottom of the
collectors should be at least 4 ft from the ground to allow for snow
shedding.
-
Be sure to use the
appropriate
mixture of antifreeze in your collectors! Use the worst recorded
temperature for your area to determine the level of protection you will
need. Refer to the manufacturer's charts for the right mixture.
-
Be sure to
size your expansion tank to
the volume and heating capacity of your system.
