[TRNSYS-users] Solar Thermal Freeze Protection for water only systems.

[Fred Betz <fbetz@aeieng.com>]

All,

What approaches have you taken to estimate the energy cost of freeze protection for solar thermal systems. 

What I have been doing is modeling it without any freeze protection. I then take the hours that the water in the pipes is below 2 degree C and determine what it would take to heat that water with electric resistance heat tape as I know what the volume of liquid is in the pipe. I ignore the mass of the pipe as I also don't get the effect of heat escaping from the building through the pipes. 

Obviously this isn't as big of a problem for closed loop glycol systems, but that isn't always practical. 

Thanks,

Fred


FRED BETZ  PhD., LEED AP 
SUSTAINABLE SYSTEMS ANALYST
 
AEI | AFFILIATED ENGINEERS, INC.  
5802 Research Park Blvd. | Madison, WI  53719

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