SOLAR HEATING SYSTEM CONSTRUCTION LOG
October 17: Filling the solar system
Today I finished
all the solar system plumbing. The final assembly
was the heating manifold that feeds water to the floor.
Here it is close up and in context with the Aquastar propane heater
above - and the water tank to the right.
The gray box in the upper left is the pump relay box that I
built to control the water circulation pumps (brown circles),
it is wired to a digital thermostat that I located in the main
room of the workshop. I have programmed it to set back the
temperature to 65 at night, and bring it up to 70 after sunrise.
The big event
today was filling the system with water and
glycol mixture. The first step was filling the solar collectors
with a 50/50 glycol (antifreeze) mixture. Incidentally, this is
DowFrost HD a specially formulated proplyene glycol
- a non- toxic version of ethylene glycol used in
automobile radiators. Do NOT use automobile antifreeze
it is very toxic and will degrade in your system.
I did this with a small transfer pump made by Wayne that I found at the
local hardware store for about $80.00 where I also got some some clear tubing
that I put hose connectors on - this lets me see any air bubbles that must be
eliminated in the system before it is fired up.
I discovered several leaks around the
heat exchanger and had to pull it out to tighten several adapters.
Fortunately this process was made easier by my foresight.
I had installed unions on all the heat exchanger connections
to allow the whole thing to be removed for service.
After replacing it I refilled the glycol - and no leaks!
Then on to the
water system. I attached the garden hose to the
bottom of the water tank and filled it first. I have no running water
in the barn, so I have to run a hose from the house over 60 feet
The water eventually
filled up the tank and was allowed to drain
out the window from another connection to that I could again
be sure to remove all the air bubbles. I later re-connected the hose
to flush air out of the floor plumbing loops too.
I worked into
the night and plan to get up just after sunrise to watch
the solar system kick in. As the sun strikes the solar electric panel it will
power the DC pump that will circulate water through the 2 solar collectors
as they heat up. It will be a thrill to see my temperature gauges climb.
The propane company
comes out tomorrow morning to hook up
the gas line to the Aquastar backup heater. Then I will be totally
NOTE! If you are building a system like mine that has circulation pumps that run on solar panels, I am producing an inexpensive Differential Temperature Controller that runs on 12 Volt PV power. It will increase your system efficiency significantly.