As I mentioned in the BTU thread, I have a wall air heater I built a couple of years ago. The idea was on the net several years ago. I made adaptations to fit my need.
Basically the south wall is glass and behind the glass is a cavity or box in which fiber furnace filter media is hung. The fiber is painted flat black on both sides. The filter is hung diagonally top to bottom in the box such that when it is warmed by the sun the cool air on the shaded side moves through the filter to the sun side while at the same time the air is warming and moving upward. The air enters the box at the bottom through a slot from the room and the air leaves the box through a slot into the room at the top. The air movement is entirely by convection and no fans or thermostat controls are used. Below is a sketch of the cross section of the unit.Swall.jpg
Bulk rolls of filter media can be found at 24" and 32" wide by 20 ' lengths. I recall getting some on eBay for less than $20 per roll. That was a while back. I see some for $40 now. My glass was old storm window inserts that were being thrown away.
Keep the box and vent slots about 6 inches deep to maintain a chimney effect. To deep a box or too large vents will reduce the velocity of the air through the box. You want it to get into the room and velocity is the means to get it there.
Below is a picture from the outside of my shop.swall5.JPG
This is a close up through the glass from the outside. Ignore the reflection of the junk in the glass. Provide the ability to remove the glass for cleaning. This is a wood shop and sawdust gets everywhere. I remove the glass each fall and clean. While the glass is off I remove the filter and blow the dust out of it. swall4.JPG
This is a view of the floor vent slot from the inside. I've used a piece of filter to catch some of the sawdust before the air gets into the box.swall2.JPG
This is a view of the top vent slot before I added a plastic curtain to close it at night.swall3.JPG
Make sure that the room is well insulated. You can gain heat but is does little good if there is a lot lost through the walls and the ceiling. I had a concrete floor. I covered it with 1" foam sheet and 3/4 particle board. You need a wood frame to keep the particle board flat.
I've had this about 4 years. It works very well. Today is a very sunny 18 degrees F and I can work in a t-shirt.
Basically the south wall is glass and behind the glass is a cavity or box in which fiber furnace filter media is hung. The fiber is painted flat black on both sides. The filter is hung diagonally top to bottom in the box such that when it is warmed by the sun the cool air on the shaded side moves through the filter to the sun side while at the same time the air is warming and moving upward. The air enters the box at the bottom through a slot from the room and the air leaves the box through a slot into the room at the top. The air movement is entirely by convection and no fans or thermostat controls are used. Below is a sketch of the cross section of the unit.Swall.jpg
Bulk rolls of filter media can be found at 24" and 32" wide by 20 ' lengths. I recall getting some on eBay for less than $20 per roll. That was a while back. I see some for $40 now. My glass was old storm window inserts that were being thrown away.
Keep the box and vent slots about 6 inches deep to maintain a chimney effect. To deep a box or too large vents will reduce the velocity of the air through the box. You want it to get into the room and velocity is the means to get it there.
Below is a picture from the outside of my shop.swall5.JPG
This is a close up through the glass from the outside. Ignore the reflection of the junk in the glass. Provide the ability to remove the glass for cleaning. This is a wood shop and sawdust gets everywhere. I remove the glass each fall and clean. While the glass is off I remove the filter and blow the dust out of it. swall4.JPG
This is a view of the floor vent slot from the inside. I've used a piece of filter to catch some of the sawdust before the air gets into the box.swall2.JPG
This is a view of the top vent slot before I added a plastic curtain to close it at night.swall3.JPG
Make sure that the room is well insulated. You can gain heat but is does little good if there is a lot lost through the walls and the ceiling. I had a concrete floor. I covered it with 1" foam sheet and 3/4 particle board. You need a wood frame to keep the particle board flat.
I've had this about 4 years. It works very well. Today is a very sunny 18 degrees F and I can work in a t-shirt.
Comment