Solar thermal panels to heat garage floor
New to the board so I may be in the wrong pew. I have built a 620 sq. ft. garage with 220 feet of 1/2 inch pex pipe at the bottom of a 4 inch concrete floor. I would like to use about 40 square feet of solar panels to heat antifreeze and pump it through the pex tubing. I'm puzzled about the pump size and also whether it would be possible to just cascade the fluid over the metal plate absorber without using tubing? If tubing is necessary what size and how much is about right per square foot of collector? Any comments or suggestions would be appreciated or point me to a book which has some detailed guidance. Thanks, jabber.