Terry Fenwick, Harwood, Ontario
I installed my two 30 tube collector system in late November 2010.
My design goal was to maximize the winter heat gain to help heat water used for radiant floors and my domestic hot water. I have started with two 30 tube collectors set at a 60 degree slope and plan to add two more collectors later this summer. I enlarged and converted an old cedar hot tub into a 220 gallon storage tank with 4 copper heat exchanger coils in it. The tank water is heated by the solar glycol loop and by my ground source heat pump. The other exchanger coils in the tank are for domestic hot water, radiant floor heating and a heat dump coil which will send excess summer heat to my outdoor hot tub. I am using very basic ETCs (Electronic Temperature Controllers) to operate the solar loop pump, domestic hot water recirculation pump and activate the heat pump when the storage tank temperature falls below the required level.
As I have built much of the system components myself, I have done lots of tweaking and checking the system function, wanting to learn how well the system operates, when and what adjustments to make. After several months, it still gives me a thrill to see the solar loop raising the storage tank temperature from 100 F to 140 F on a sunny spring day. With only two (of 4 planned) collectors in place, I have not had any need to "dump" excess heat from the storage tank. I have not yet done a review and comparison of my electrical consumption since adding the solar hot water heating but I do know that I am now doing about 90% of my DHW heating with the solar collector (my heat pump use is very noticeably less since adding the solar collectors). When I do an energy use comparison, I will update you on my energy savings.
Future plans are to add at least two more 30 tube collectors to the roof (perhaps 3 more) and to change the solar loop pump to a PV panel powered pump. I will also revisit (and increase?) the solar loop exchanger coils in the storage tank, currently they drop the loop temperature by about 8F and the design goal is to drop the loop temperature by about 15F.
I did encounter a few problems during my system installation, most of which I documented in the photos Stefan will post on this site. Most irritating problem was in using silver solder for the header lines, I had to resolder one section of pipes several times. I finally cut the pipe section out, brought it into the shop to resolder the problem connections, pressure tested the new joint (failed the test!), cut new pipes and tried soldering it again! The problem is in joining copper pipes to heavier brass fittings, it is difficult getting the brass fittings hot enough to accept the silver solder. My other concern is the final siting of the collectors... because of the steep collector angle and shallow pitch of my roof, the top foot of the collectors are visible over the ridge line of the roof, this is an aesthetic problem for my wife and I. Solution will be to lower the collectors down the roof line when I add the extra collectors this summer.
Solar storage tank made from a 220 gallon old hot tub. The height was extended to increase the tank volume.
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