Painting a concrete floor!

[NutmegCT]

With heating oil now at $6/gallon ... I want to use my enclosed insulated porch as a passive solar heat source.

Plain concrete floor of about 400 sq ft. South facing dual pane floor to ceiling thermal barrier windows, total area ca. 200 sq ft. Sun warms the concrete during day, and I'll cover window with foam panels at night to slow down heat loss.

What's a good way to make the concrete surface black, to absorb as much solar radiation as possible? Epoxy is expensive and "pretty", but as a frugal Yankee, just making the concrete black is the goal.

Thanks.
Tom M.

 

[Gliderman8]

How do you intend to move the heat from the slab into your living space?

 

[NutmegCT]

Thanks Elliot. A box fan on the floor of the doorway into the living room will move cooler air from the LR into the warmed porch, allowing warm porch air to enter the LR.

Hope that's what you mean.

 

[Gliderman8]

Thanks Elliot. A box fan on the floor of the doorway into the living room will move cooler air from the LR into the warmed porch, allowing warm porch air to enter the LR.

Hope that's what you mean.

Ok, that sounds good. Now, will the glass have shades on them? What I mean is that you would keep the shades open during the daylight but when the sun goes down most of that heat will go back out the uncovered glass window. The shade will help keep the heat in when they are closed.

 

[NutmegCT]

check! dark concrete becomes a heat sink and retains heat into early evening. To prevent "reverse heat flow" to cooler glass at sundown, I'll have insulated drapes to pull closed then re-open in the morning on sunny/partly sunny days.

I heated the first floor of my previous house with convective passive solar box I built on the south wall of the kitchen. Cost $25, saved over $1000 in the first two years.

 

[NutmegCT]

Wondering what type of paint/stain I should use on that concrete floor. Just plain old masonry paint, or ...?

Definitely want a flat or matte, not slippery or shiny.

 

[Gliderman8]

Maybe stop in to a Sherwin Williams store (or similar) to get some advice for a paint to use.

 

[Hamish Racing]

Black board paint ?

 

[NutmegCT]

Thanks gents. I'm thinking a flat black stain (not paint) with Solar Absorptance (SA) rating close to 1.0 (100% absorption) should do the trick.

Will need to see if that's on the market, and what prep it will need.

Slowly I turn - step by step - inch by inch - Niagara Falls! (remember that?)

 

[Bob McElwee]

Will you be able o use it as a sauna in the summer B-)

 

[NutmegCT]

Sauna! that's an added benefit!

(In warm months, awning prevents the higher sun from hitting the concrete, and the black surface will be covered by an "outdoor carpet".)