Welcome! Here are the website rules, as well as some tips for using this forum.
If you've found help here, check back in to let us know how everything worked out.
It's a great way to thank those who helped you.
Solar single zone radiant heating system design help
I am building a 320 sq. ft. detached workshop that has good roof-top solar access, along with water and electricity, no gas and no south facing windows or walls, so no solar heat gain. A single zone of Wirsbo ½" tubing has been installed in the new slab, and I need to design the rest of the system.
I have radiant heating in the main house, which uses a Navien CH-240 gas water heater for both radiant heat and dhw. I installed the closed loop radiant heat system in 1992 using Wirsbo tubing and zone manifold, a Tekmar 254 boiler controller and a Grundfos circulating pump. There are no mixing valves in the system; mixing is controlled by a pair of ball valves. This system has given me 25 years of excellent service, although it has been redesigned a few times along the way. I'm located in Salinas California, so I only get a few days a year below freezing temps.
For the new shop, I am considering a roof-mounted Sunbank SB40G solar water heater for the heating, with an electric on-demand water heater. This would be a closed loop system since I have no need for dhw in the shop. I would use a Grundfos circulating pump. The solar water heater has a built-in 40 gal. tank. I've never designed a heating system with two heat sources, so what else will I need?