Is a heat sink needed in solar evacuated tube system?

PMMWYO

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Nov 5, 2021
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Planning to install in floor piping and boiler system with DHW included with heat exchanger tank. Boiler will handle heating glycol to temp necessary for DHW and then use control valve to cool for in floor heat temperature. I want to put in evacuated tube collectors to heat glycol prior to boiler, i am not sure however if i would need a heat sink for times when demand for heat are low, abs in summer when system is essentially turned off. In winter it is regular to have temperatures well into the (-30F) range and have periods of 60 or more days that do not get above freezing what so ever, then summer will not need heat for 2 to 3 months at all.
 

740GLE

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I’m not 100% sure but I thought evacuated tubes deal with stagnation pretty well, once your thermal holding tank is up to temp the circulating pump just shuts off. It’s rough in the glycol but if you go with larger storage tank that can handle 180/200f, periods of stagnation will drop to low DHW demand.
 

PMMWYO

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I’m not 100% sure but I thought evacuated tubes deal with stagnation pretty well, once your thermal holding tank is up to temp the circulating pump just shuts off. It’s rough in the glycol but if you go with larger storage tank that can handle 180/200f, periods of stagnation will drop to low DHW demand.
That is kind of where i am at also, I'm just looking to get some confirmation on my thought process! Thanks for the reply!
 

740GLE

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Might want to reach out to local HVAC companies of vendors of evacuated tube systems they might have more knowledge than this group here.
 

PMMWYO

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I will ask my son in law when i see him over the holiday! He does HVAC for a living, i just haven't had a chance to visit much.
 
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