I've been trying out induction cooking on a small one-burner unit, with a large cast iron pan. I'm getting the expected hot spot in the center of the pan, and a serious temperature falloff toward the sides. No surprise there - the induction element is about 7" (I dismantled the unit to check)...
Argh - good point. Concrete does tend to feel cool, even in the summer. Though if it does actually come close to equalizing to room temp at the boundary as the napkin numbers suggest, maybe it'll be a matter of "cool" as opposed to "unbearable".
Someone was telling me that a normal 6" slab...
Looking at the RaL range given in wikipedia, it looks like at the very low end of RaL, the difference in dT would be a factor of 1.35 (from your calculated figure). So yeah, very low sounding.
On the other hand, googling for people talking about their concrete floors in winter brings nothing...
Thanks for the response. And yes, I see I did impose my Imperial bias on the area constant. (I vaguely remember a big push for the conversion to metric in the U.S. somewhere around my 6th grade year, but apparently the country as a whole gave up after that. As evidenced by the fact that the...
I'm trying to do a rough calculation to find the "operating temperature" of a concrete floor. I've found a paper that discusses calculations for rate of heat loss from the slab to the earth: here. (It's a Word file - don't freak out.) Which gave me a fairly reasonable figure of ~2400Btu/hr...
Hey guys - thanks for the responses. In thinking a bit about their "downward transmission" argument, it still doesn't sit 100% comfortably with me. The pdf seems to argue that the heated area is wider for their element, giving faster transmission to the air in the room. Surely this argument...
I'm trying to evaluate floor heating systems for installation in my new studio, and I have to admit that my thermodynamics is a bit rusty... But I came across the following, and I could use a sanity-check.
Basically, it's an in-slab heating element that claims to be 2.5x "more efficient"...