My shop wall air heater

[hubster5]

Then I would say have a good time learning about the technology.

I just didn't want you to spend a lot of cash on a pv system that would not support your needs but empty your bank account.

Point taken! This building currently has no power at all - so having a little will be nice to keep the rechargeables topped off, and maybe a 12v light or two. I have a generator if i need real power... and I may be inclined to scale up the solar system down the road - just a learning project more than anything!

[SunEagle]

yes - it is sold rock, although I have not explored diverting around, as that would involve sneaking over the property line a bit...

But the limited solar install will only cost a couple hundred bucks + I get to learn the basics of the system, and I have a source for no/low cost batteries - so I am in for the experience as much as the practical gains.

Then I would say have a good time learning about the technology.

I just didn't want you to spend a lot of cash on a pv system that would not support your needs but empty your bank account.

[hubster5]

Even if the run between the house and the shed is 1000 feet it is still cheaper to run the cable instead of building an off-grid pv system. Of course if the ground is solid granite the price would go up but a "ditch witch" is cheap to rent and make your cut to lay U/G cable.

yes - it is sold rock, although I have not explored diverting around, as that would involve sneaking over the property line a bit...

But the limited solar install will only cost a couple hundred bucks + I get to learn the basics of the system, and I have a source for no/low cost batteries - so I am in for the experience as much as the practical gains.

[SunEagle]

That's the easiest one of all - there is currently no power at all to this building. It is set far enough from the house to be cost prohibitive to make a run - at least that is my excuse for the panel kit that I have waiting to go up on it (dual project heat & power) - my parallel project is to get some solar up and running out there - just some lights and charge tools at first - then with some measure of success - a potential scale up on the panels and batteries...

That is why I was asking the forced air questions earlier - I will have limited power, maybe enough to run some 12v computer fans, but no serious wattage, in the beginning.

Even if the run between the house and the shed is 1000 feet it is still cheaper to run the cable instead of building an off-grid pv system. Of course if the ground is solid granite the price would go up but a "ditch witch" is cheap to rent and make your cut to lay U/G cable.

[hubster5]

If you put in a ceiling for insulation, keep in mind that you may have to redo your lighting significantly to get comparable are coverage with lower fixtures. Are your current luminaires above or level with the rafters?

That's the easiest one of all - there is currently no power at all to this building. It is set far enough from the house to be cost prohibitive to make a run - at least that is my excuse for the panel kit that I have waiting to go up on it (dual project heat & power) - my parallel project is to get some solar up and running out there - just some lights and charge tools at first - then with some measure of success - a potential scale up on the panels and batteries...

That is why I was asking the forced air questions earlier - I will have limited power, maybe enough to run some 12v computer fans, but no serious wattage, in the beginning.

[inetdog]

You got it - just rafters - I had to move the first one up to get a good door put in (sawzall work). I would estimate that the bottom of the rafters are at about 7' - maybe less... comfortable where they are for my height - but not much play.

If you put in a ceiling for insulation, keep in mind that you may have to redo your lighting significantly to get comparable are coverage with lower fixtures. Are your current luminaires above or level with the rafters?

[hubster5]

I assume this is an old building with peaked roof on rafters and not trusses.

You can insulate the roof by placing insulation between the rafters. This would be easy if the rafters were 2x6. If they are only 2x4 then maybe you can add some sticks on their bottom to make them deeper. Use an insulation thickness that leaves an inch space to the roof deck.

As an alternative you can make an insulated horizontal ceiling at a comfortable height for your size by suspending joists from the rafters. This ceiling would not go all the way to the sides of the barn. The area from the edge of the ceiling to the wall would be insulated between the rafters. The ceiling would have to only support itself so it can be put up like a suspended ceiling with wire ties and a light weight grid frame.

Tell me a little more about the roof construction and we can work out a plan.

Insulating the top will significantly improve heat retention once the sides are closed.

You got it - just rafters - I had to move the first one up to get a good door put in (sawzall work). I would estimate that the bottom of the rafters are at about 7' - maybe less... comfortable where they are for my height - but not much play. I have another bldg that I remodeled a few years ago.. it was about 6' - those I cut out completely and moved up 10" or so, then hung OSB and insulated, so I am not new to the construction part, just had not really considered the heat loss I would be battling with the ceiling (sometimes I tend to miss the obvious). And the rafters are all rough cut sawmill lumber - and the sizes appear to vary from 4" to 6" - (This all came from the time when you made do with what you had- and I am wired that way to an extent myself).

I would likely just panel the ceiling with OSB or the like, something thin if I can get it cheap, and roll out the pink stuff.

The "loft" was originally used to store lumber across the rafters, with a small door to the outside for "handing up" the lumber. I have removed that door and finished the front - no windows, just one door and solid siding. I figured if I wanted windows I could cut them in later, as the front of the bldg was basically falling off... now it is good to go, and I am working my way around the 2 remaining sides with studs and t-111. The 4th side has a smaller enclosed shed built off of it - so I will likely need to use OSB or something to fill in between the few studs on that wall before insulating. (That wall is inaccessible from the outside).

[brododge]

I assume this is an old building with peaked roof on rafters and not trusses.

You can insulate the roof by placing insulation between the rafters. This would be easy if the rafters were 2x6. If they are only 2x4 then maybe you can add some sticks on their bottom to make them deeper. Use an insulation thickness that leaves an inch space to the roof deck.

As an alternative you can make an insulated horizontal ceiling at a comfortable height for your size by suspending joists from the rafters. This ceiling would not go all the way to the sides of the barn. The area from the edge of the ceiling to the wall would be insulated between the rafters. The ceiling would have to only support itself so it can be put up like a suspended ceiling with wire ties and a light weight grid frame.

Tell me a little more about the roof construction and we can work out a plan.

Insulating the top will significantly improve heat retention once the sides are closed.

[hubster5]

Any time you want to move air horizontally through a pipe you will need a fan. I don't know the size of the area you want to heat but a horizontal fan at the collector exhaust vent would probably be sufficient without the pipe.

My shop is 16 feet by 20 feet with a 10 ft ceiling height. The open vents at the top of my collectors provide enough air flow to warm the room. But, the sun has to shine and it takes an hour or so.

I am also well insulated and have tight doors. The ceiling is 6 inch fiberglass plus paper based suspended ceiling tile. The walls are 3 inch fiberglass plus covering. The floor is concrete covered with 1 inch foam and topped with 3/4 inch particle board. This room is inside a barn with one outside wall to the east and one outside wall to the south. The other two walls are within the unheated and uninsulated barn. Once my shop is warm it stays that way.

For overnight and sunless days I have two 1,000 watt oil filled electric heaters to keep things from freezing. They usually operate sparingly.

If I were to make some estimation of collector size to room size (assuming it would be transferable to other construction) I have about 75 sq ft of collector attached to 3,200 cubic feet of room volume.

My shop is exactly the same dimensions, with 3 exposed sides. But that is where the similarities end... It is an old slat-board building - I can spit between the vertical cracks from 10 paces, and I am not an accomplished spitter - but I am in the process of removing the old siding, putting in 16 center studs and T-111 siding... even then it will not be tight by any means (eaves, ceiling). I may insulate and OSB the inside. there is no ceiling, only rafters and a tin roof (I could put one in, but the rafters are lowish, and I am tallish). I do have the space to build twin heaters, which I have considered. I have plenty of storm window salvage - like you.

I guess getting it insulated is the key - I have a lot of work to do...

Thanks again, and congrats on your success with your heater!

[brododge]

Any time you want to move air horizontally through a pipe you will need a fan. I don't know the size of the area you want to heat but a horizontal fan at the collector exhaust vent would probably be sufficient without the pipe.

My shop is 16 feet by 20 feet with a 10 ft ceiling height. The open vents at the top of my collectors provide enough air flow to warm the room. But, the sun has to shine and it takes an hour or so.

I am also well insulated and have tight doors. The ceiling is 6 inch fiberglass plus paper based suspended ceiling tile. The walls are 3 inch fiberglass plus covering. The floor is concrete covered with 1 inch foam and topped with 3/4 inch particle board. This room is inside a barn with one outside wall to the east and one outside wall to the south. The other two walls are within the unheated and uninsulated barn. Once my shop is warm it stays that way.

For overnight and sunless days I have two 1,000 watt oil filled electric heaters to keep things from freezing. They usually operate sparingly.

If I were to make some estimation of collector size to room size (assuming it would be transferable to other construction) I have about 75 sq ft of collector attached to 3,200 cubic feet of room volume.

[hubster5]

Hi - I love the simplicity of your heater, relying on convection alone to move the heat. I am starting a similar project, and you have given me some things to reconsider. I was of the thinking that the intake and output should be constructed a good distance away from each other, to promote circulation of the air throughout the entire heated space - my scribble has the outflow into maybe 6" flex duct with a 15' run to the back (north end) of the shop, and maybe to the floor? with the intake, like yours, close to the collector, with maybe a small forced air plenum feeding it.
Could you comment on the ambient temp at the other end of your room? Do you use fans to circulate the air? With my thoughts of having a flex duct run - I am sure it creates resistance, thus would likely require some forced air at some point.

Thanks again - the idea for the filters material is intriguing!

hubser5

[brododge]

It works well just as shown. However, I was making too much dust in my shop. So, I installed a new dust collection system. That keeps me healthy as well as keeps the dust from collecting in the filter material of the wall heater.

Herb

[marmelada]

I wander if you modified anything after this discussion. If so, would you please share how did it turn out?
thanks

Mod note - welcome and please participate but the next time you post your link I hit the ban button

[hyder]

reply

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.[ATTACH=CONFIG]2569[/ATTACH]

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.[ATTACH=CONFIG]2572[/ATTACH]


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. [ATTACH=CONFIG]2573[/ATTACH]


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.[ATTACH=CONFIG]2570[/ATTACH]


This is a view of the top vent slot before I added a plastic curtain to close it at night.[ATTACH=CONFIG]2571[/ATTACH]

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.

Very nice. I love seeing creativity of all sorts, ecspecialy when it is energy saving.

Keep creating,
hyder

[brododge]

You make some good points. I agree that the aluminum would be more costly. How loose is the weave in the filter mat you used meaning how far can the light penetrate into the fabric?

You can see the filter media in the picture of the floor intake slots. It is about an inch thick and some light goes through it. The back wall of my box is lined with aluminum foil covered foam insulation (I forgot to add that to the diagram) to reflect stray light to the backside of the filter mat. I spray painted the mat in a flat black on both sides and a majority of the inner fibers got paint. But the voids are large enough that there was no paint globbing (nice word) to mess up air flow.

I also forgot to say that each column of windows is a separate box. That allows a rigid frame to provide structure to hold up both the windows and the filter media.