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Old 01-11-16, 01:28 AM   #7
SDMCF
Apprentice EcoRenovator
 
Join Date: Jul 2014
Location: Finland
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Let me add my 2 cents to this topic, since my system is similar but different. Similar in that I have both solar and GSHP and I use the solar for both space heating and hot water. Different in that the solar and GSHP are coupled in an entirely different way.

My solar collectors are 100 evacuated tubes, vertically mounted on the (south-facing) end of my house. The hot fluid from the panels can be diverted to one or both of two heat exchangers (or to pipes under our front steps to clear ice & snow).

The house is heated with radiators and one of the heat exchangers is connected to the return line from one of the radiators. This way the heat gets into the space heating system for the whole house and the GSHP just sees the return flow being warmer and so doesn't need to run, or doesn't need to run so much.

I like this approach because it is simple. Heat collected by the solar panels contributes to our space heating and reduces the GSHP run time, but does not require any link between the solar kit and the GSHP other than the heat exchanger. Either one can and does operate independent of the other, with no conflict.

Our use of radiators rather than under-floor heating is because this is an old house which already had radiators and retro-fitting under-floor heating was not a practical option. Under-floor heating would be better, but the radiators do work OK.

The second heat exchanger I mentioned is used to put the heat into the DHW system. That is not used so much for various reasons.

The solar panels produce about 7000 kWh per year and most of that goes into space heating. Ours is a large old house and in our climate for most of the year we can use all the solar heat we collect.

We installed the solar panels in 2005 and the GSHP in 2007. Both have been reliable until now, but we currently have problems with both. The GSHP currently only runs for an hour or so and then gives an alarm. I believe the pump which circulates fluid through the field loop is the culprit. A replacement is on order and we should have that on Wednesday. Plus the fluid in the solar panels froze. It has anti-freeze in it and has been fine for years, so why did it freeze now? I don't know. I have it thawed out now and I'll get more anti-freeze today. Losing either of these system would be awkward but losing both together when the temperatures have been around -30C (-22F) has been a pain. So just at the moment things are a bit chilly but overall both the solar panels and the GSHP have been good investments.
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