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Old 03-13-15, 12:43 PM   #4
osolemio
Hong Kong
 
Join Date: May 2010
Location: Hong Kong
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Quote:
Originally Posted by Daox View Post
Very nice setup.

What are the two three way valves in the solar panel to tank circuit for?
I am happy you ask that question

The primary circuit is a glycol-water mix, to prevent freezing, secured down to -20 C (-4 F). Despite that I have a function to run to keep it from getting below -10 (14 F), just in case.

Anyway, that primary system, consists mainly of three parts:

1. Solar panels (left)
2. Heat exchanger to secondary (plain water) system (middle)
3. Heat exchanger inside a 1000 liter (375 USG) hot water buffer. (right side)

With those two three-way valves, I can transfer heat between any or all of these three units, except, the middle heat exchanger is always active when the primary pumps is running - however - as long as the secondary system pump is off, then it doesn't matter, and in reality as I wrote, I can combine the three any way I want.

At the moment where it is just below freezing at night, sunshine at day up to around 10 C (50 F), it starts out with the solar panel and secondary system only (bypassing the hot water buffer in the top left corner of the schematic).

When the water from the solar panel gets sufficiently hot for the hot water buffer, the three way valve in the left side opens for flow into all three systems in primary, as can be seen here:



It's not a lot at this stage. Due to a system orientation of 160 degrees (South-South-East), peak is around 11 am. Here at 1:52 pm, the heat is decreasing and transfer going down.

Note the updated design. You can also click certain items now, for more info.

Ask in PM if you want a code to see it live.
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Space heating/cooling and water heating by solar, Annual Geo Solar, drainwater heat recovery, Solar PV (to grid), rainwater recovery and more ...
Installing all this in a house from 1980, Copenhagen, Denmark. Living in Hong Kong. Main goal: Developing "Diffuse Light Concentration" technology for solar thermal.
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