This panel was designed to assist my Spa's electric
heater and not intended to replace it.
| ASSEMBLY: The Frame was assembled with a 33" x 44"
piece of ½" plywood with 2 by 4 sides using dry wall screws. 2"
holes were cut in the left and right side 2 by 4’s to accommodate
the inlet and outlet. All wood pieces were waterproofed prior to
assembly. The PVC pipe was cut into 7 lengths, 5 pieces 36" and 2
pieces 41 ½". The two longer pieces were used for the inlet
and outlet sections. The elbow joints were mated together with 2 ½ "
sections of PVC. All PVC was sanded with 360 grit sand paper so the
paint would stick. The PVC assembly was cemented together in the frame.
The PVC plumbing was anchored to the plywood back with 10" Zip ties
through 3/8" holes drilled on each side of each section of PVC. 12
zip tie anchors were used. Then the garden hose adapters were cemented
to the inlets and outlets. All the panel seams were sealed with silicone
caulking to make it as water tight as possible. Once the caulking was
dry the entire assembly was primed and painted flat black. The paint was
allowed to dry over night prior to installing the weather stripping. Two
rows of ¾" weather stripping was used to seal the face of the
panel. A piece of 1/8" 33"x 44" Plexiglas was then
attached to panel face with ten ¾" sheet metal screws. A small
rubber washer was used on each screw to aid in sealing. |
| TEST SITE LOCATION: 32°
18.01-N / 111° 19.18-W Elevation - 2134 Feet <Marana, Arizona
USA> |
| TEST #001 : ((Feb 15, 2001)) Took the solar panel out today
to do a leak & heat up test. First I set it out at about 45°
and primed it with water. Getting the air out was harder than I
expected. After it was purged of air bubbles I shut off the input valve.
I screwed on a short piece of clear hose to the output fitting and had
it pointing up about 3’ above the panel so I could monitor the
water level while the sun heated the panel. It was a little cloudy today
so the sun was in and out every few minutes. While a cloud was blocking
out the sun the water level in the clear hose was about 10" above
the output fitting. After a cloud had passed the sun was in full force
on the panel. The water level in the clear hose climbed rapidly only
after 15 seconds or less in full sunlight. I was surprised how quickly
it reacted to the sunlight or lack thereof. Next I just let the panel
sit in the intermittent sunlight for about 40 minutes then drained it so
I could check to water temp. Without the Plexiglas cover to give a
little greenhouse action and the outside temp just 75° the water
temp still managed to get up to 126°. Looks like boiling point
temps will be possible with this setup most of the year (Arizona). |
| TEST #002 :((Feb 18, 2001)) Getting air out of the panel
plumbing seems to be a significant problem. The only way I could
completely remove all the air was to attach the panel output hose to the
Spa suction intake line. Once all the air was removed I allowed to panel
to heat so temp and flow rate could be measured. The panel produced a
decent amount of HOT water but I was disappointed in the rate of flow.
Given todays temp (80 F) the panel produce a max temp of (143 F) yet the
flow rate was less than .33 GPM. I suspect the poor flow rate is due to
the high Spa temp of 100 F. Since the weather here in Arizona is still
cool the flow rate may very well increase with 100+ temps in the summer.
But... With the panel producing usable heat at 78 F the incorporation of
a small in-line pump would stand to increase over all effectiveness.
I'll take a look at some small pumps similar to those used for small
outdoor fountains. |
| TEST #003: ((Feb 26, 2001)) Test conducted with the 1.5
AMP 120 VAC pump worked well but the pump proved to be over kill. Now
we're going to try a much smaller 12 VDC pump and aim for max flow with
minimum pump power consumption. As soon as this cloudy weather passes
I'll post results... |
| TEST #004: ((Mar 01, 2001)) Finally a sunny day! The small
12 VDC pump is working just fine kicking on when water temp reaches 125
F°. The first big problem I noticed is the Plexiglas cover is
expanding too much causing buckling and seal breach. So, I'll replace
the Plexiglas with a Glass cover but this time the glass will be
inserted within the frame and not on top. As far as performance goes,
it's a cool partly cloudy day just 68 F° yet the pump is kicking on
every 23 minutes and pumping 2 gallons of 120+ F°. Looks like this
set up will work great in Arizona clear HOT summer days. |
SPA
SOLAR WATER HEATER 
