"Free" heat for a garage. Anyone else into Solar Air Collectors?

[MAXELHOFF]

This is a solid, cheap design, imo. Obviously not for everyone.Start at 55 seconds.

[Fusion]

Cool stuff. I've watched a ton of solar heating cell videos with cells made from pop cans sprayed black. Some people even show the temp differences and other data.
I wouldn't have thought of using an alu bug net.

[Farbin Kaiber]

I like that, I could really use something like that in a future project one day.

[CabbE30]

I feel like he should have used something with a greater thermal capacity than a tiny ass screen

[MAXELHOFF]

This is why I'm hot

I wouldn't have thought of using an alu bug net.

Me either.

I like that, I could really use something like that in a future project one day.

Good to hear!

I feel like he should have used something with a greater thermal capacity than a tiny ass screen

What is your reasoning?

[evandael]

ideally, you'd have a glass screen wall, a sufficient buffer zone of air (6-12"), then a dark colored masonry or stone wall to both attract as much heat AND retain and release it throughout the day. the masonry wall has perforations at the top and bottom to allow air to enter the buffer zone, and as the sun heats up the space, the buoyancy of hot air causes circulation naturally.

that solution, of course, requires a good deal of money to retrofit, and would be better designed into new construction.


i had to ask a friend who is in architecture school what the fancy term for this system is.. it's called a 'trombe wall'. very useful on south/west facades. why not do it?

[Farbin Kaiber]

Personally, I think the aluminum screen, with some heavy black cloth that still breathes would be the way to go. Maybe the cloth on both sides of the screen, to help keep the metal hot. Looks like the panels could be so much darker...

[Pac1373]

I may have to try this on the shop building main shop building of my new farm...
I love this.

[MAXELHOFF]

custom heat

.. it's called a 'trombe wall'. very useful on south/west facades. why not do it?

Personally, I think the aluminum screen, with some heavy black cloth that still breathes would be the way to go. Maybe the cloth on both sides of the screen, to help keep the metal hot. Looks like the panels could be so much darker...

Darker is good! The way I understand this, the more heat is built-up inside the collector, the more efficiency is lost to the glazing. Think of warming the objects inside the building, not the collector. Although a hot collector is good, not at the cost of airflow. Diminishing returns applied, of course.

I may have to try this on the shop building main shop building of my new farm...
I love this.

Cool beans. Let's see a couple images of the building. I encourage site-specific modifications.I too love this.

[Q5Quint]

I do calculations for this kind of stuff at my office~

On a recent project we worked with a company that designed a 42 panel system for a building around here. The install company was a local solar company and was pissed about the design- a design by a off mountain engineer. They even said it wouldn't work, so I looked into it.

My argument was 'where do you dump the heat in the summertime'.

'Into a part of the radiant the slab' they said

*does some math*
Are you sure that slab wont be 150 degrees after 5 days and the panels still overheat and blow off from over pressure? It looks like you should be getting the equivalent of 3-4 (5) gallon sized propane tanks PER DAY of heat in the summertime.... that is a lot of grilling going on here.

'no way its cool, I'm an engineer!'

O.K. buddy.

Solar install company warns us again when they are about to turn it on. A week later it steams back, overflows/floods the mechanical room, and ruins lots of little stuff (drywall/paint/ceiling tiles mostly). Now they are trying to figure out where to dump 364,000btu because they designed a non-drainback system in a place that gets very sunny in the summertime.

Thats like $35 of 3$ per gallon propane per day, fo free.
I told them to install a pool or hot tub for the employees. The director liked that.


Back on topic for your diy panels....:
I am not a passive solar fan since that wall will work backwards at all times it is not sunny. Just like windows/skylights. They will lose more than they gain at night... since you only get good sun from 9-3.

If you used a correctly blocked off heat pipe at the top and bottom, so you could close it up at night, you also just added some insulation to the side of the house as well.... so it could work, but leaves open the possibility of letting air inside your room into a non-insulated window to get colder.

Say it is directly facing the sun or using a thermal panels off direction efficiency of 75+ percent. You should be getting about 50% or 500watts per square meter surface area of heat

1 ton of heatpump/ac power is 12,000 btu. 1 btu is 3.4 watts.
So 500w/3.4 = 147btu per hour.
So to get my free 1 ton I would need 12,000/147 = 81 sq meters of collectors. And close them up at night or I might lose whatever I gained.

Remember that higher efficiency hydronic solar-thermal heating still needs 10+ 4x8 panels on your roof to make a dent in your home heating.... and then it will be overheating all summer.

Instead of spending $1000 per copper hydronic panel it makes a lot more sense to do the diy solar air like you have shown, though making them your whole roof is a better idea since you need so many. 81 sq meters is 871 sq ft.

The other option is to use solar pv and a heat-pump. Spend 3-5k on some mitsubishi mini splits and another 5k on some rooftop pv. Then get a heatpump water heater too for about $1000. No plumbing, no pumps, and $ for $ you are getting the cheapest btu possible.

I just installed an extra mini split in my garage for this reason- it can keep it 60 degress when its 20 outside even with 2 9ft roll up garage doors leaking like a sieve. If it was bigger or unattached, or I didnt have $1500 to blow, I would have just put in a woodstove.

Solar is a great idea- but it has to be paired with ultra-high efficiency for it to be worth it. That is why the PV electricity + heat pumps work best, followed by thermal hydronic and air.

Here is a neat comparison of some high efficiency homes. We are starting to build them out of dirt again.

http://capla.arizona.edu/hed/docs/CivanoHomes2003.pdf

I have done a few 'normal' homes hitting 50cents per square foot per year, so I know 25 is possible. My house is down to about a dollar but it was built in the 50s with 2x4 walls.


At .10 per Kw electricity, one meter square of that solar collector is giving you 5 cents of heat per hour.
Compared to a 3-4 cop heat pump which would give you the same heat for 2 cents per hour.

Sorry for rambling- boring lunch break today.

[MAXELHOFF]

disretard

I do calculations for this kind of stuff at my office~

On a recent project we worked with a company that designed a 42 panel system for a building around here. The install company was a local solar company and was pissed about the design- a design by a off mountain engineer. They even said it wouldn't work, so I looked into it.

My argument was 'where do you dump the heat in the summertime'.

'Into a part of the radiant the slab' they said

*does some math*
Are you sure that slab wont be 150 degrees after 5 days and the panels still overheat and blow off from over pressure? It looks like you should be getting the equivalent of 3-4 (5) gallon sized propane tanks PER DAY of heat in the summertime.... that is a lot of grilling going on here.

'no way its cool, I'm an engineer!'

O.K. buddy.

Solar install company warns us again when they are about to turn it on. A week later it steams back, overflows/floods the mechanical room, and ruins lots of little stuff (drywall/paint/ceiling tiles mostly). Now they are trying to figure out where to dump 364,000btu because they designed a non-drainback system in a place that gets very sunny in the summertime.

Thats like $35 of 3$ per gallon propane per day, fo free.
I told them to install a pool or hot tub for the employees. The director liked that.


Back on topic for your diy panels....:
I am not a passive solar fan since that wall will work backwards at all times it is not sunny. Just like windows/skylights. They will lose more than they gain at night... since you only get good sun from 9-3.

If you used a correctly blocked off heat pipe at the top and bottom, so you could close it up at night, you also just added some insulation to the side of the house as well.... so it could work, but leaves open the possibility of letting air inside your room into a non-insulated window to get colder.

Say it is directly facing the sun or using a thermal panels off direction efficiency of 75+ percent. You should be getting about 50% or 500watts per square meter surface area of heat

1 ton of heatpump/ac power is 12,000 btu. 1 btu is 3.4 watts.
So 500w/3.4 = 147btu per hour.
So to get my free 1 ton I would need 12,000/147 = 81 sq meters of collectors. And close them up at night or I might lose whatever I gained.

Remember that higher efficiency hydronic solar-thermal heating still needs 10+ 4x8 panels on your roof to make a dent in your home heating.... and then it will be overheating all summer.

Instead of spending $1000 per copper hydronic panel it makes a lot more sense to do the diy solar air like you have shown, though making them your whole roof is a better idea since you need so many. 81 sq meters is 871 sq ft.

The other option is to use solar pv and a heat-pump. Spend 3-5k on some mitsubishi mini splits and another 5k on some rooftop pv. Then get a heatpump water heater too for about $1000. No plumbing, no pumps, and $ for $ you are getting the cheapest btu possible.

I just installed an extra mini split in my garage for this reason- it can keep it 60 degress when its 20 outside even with 2 9ft roll up garage doors leaking like a sieve. If it was bigger or unattached, or I didnt have $1500 to blow, I would have just put in a woodstove.

Solar is a great idea- but it has to be paired with ultra-high efficiency for it to be worth it. That is why the PV electricity + heat pumps work best, followed by thermal hydronic and air.

Here is a neat comparison of some high efficiency homes. We are starting to build them out of dirt again.

http://capla.arizona.edu/hed/docs/CivanoHomes2003.pdf

I have done a few 'normal' homes hitting 50cents per square foot per year, so I know 25 is possible. My house is down to about a dollar but it was built in the 50s with 2x4 walls.


At .10 per Kw electricity, one meter square of that solar collector is giving you 5 cents of heat per hour.
Compared to a 3-4 cop heat pump which would give you the same heat for 2 cents per hour.

Sorry for rambling- boring lunch break today.

.
Wow! I can't believe they let you drink at lunch.









.

[AndrewBird]

Some DIY here:

http://www.instructables.com/id/Solar-Heater/

This one is cool because it is window mounted:

http://www.instructables.com/id/Window-Mounted-Solar-Hot-Air-Furnace-Aluminum-Sof/

[StuartHines]

I do calculations for this kind of stuff at my office~

On a recent project we worked with a company that designed a 42 panel system for a building around here. The install company was a local solar company and was pissed about the design- a design by a off mountain engineer. They even said it wouldn't work, so I looked into it.

My argument was 'where do you dump the heat in the summertime'.

'Into a part of the radiant the slab' they said

*does some math*
Are you sure that slab wont be 150 degrees after 5 days and the panels still overheat and blow off from over pressure? It looks like you should be getting the equivalent of 3-4 (5) gallon sized propane tanks PER DAY of heat in the summertime.... that is a lot of grilling going on here.

'no way its cool, I'm an engineer!'

O.K. buddy.

solar panels install company warns us again when they are about to turn it on. A week later it steams back, overflows/floods the mechanical room, and ruins lots of little stuff (drywall/paint/ceiling tiles mostly). Now they are trying to figure out where to dump 364,000btu because they designed a non-drainback system in a place that gets very sunny in the summertime.

Thats like $35 of 3$ per gallon propane per day, fo free.
I told them to install a pool or hot tub for the employees. The director liked that.


Back on topic for your diy panels....:
I am not a passive solar fan since that wall will work backwards at all times it is not sunny. Just like windows/skylights. They will lose more than they gain at night... since you only get good sun from 9-3.

If you used a correctly blocked off heat pipe at the top and bottom, so you could close it up at night, you also just added some insulation to the side of the house as well.... so it could work, but leaves open the possibility of letting air inside your room into a non-insulated window to get colder.

Say it is directly facing the sun or using a thermal panels off direction efficiency of 75+ percent. You should be getting about 50% or 500watts per square meter surface area of heat

1 ton of heatpump/ac power is 12,000 btu. 1 btu is 3.4 watts.
So 500w/3.4 = 147btu per hour.
So to get my free 1 ton I would need 12,000/147 = 81 sq meters of collectors. And close them up at night or I might lose whatever I gained.

Remember that higher efficiency hydronic solar-thermal heating still needs 10+ 4x8 panels on your roof to make a dent in your home heating.... and then it will be overheating all summer.

Instead of spending $1000 per copper hydronic panel it makes a lot more sense to do the diy solar air like you have shown, though making them your whole roof is a better idea since you need so many. 81 sq meters is 871 sq ft.

The other option is to use solar pv and a heat-pump. Spend 3-5k on some mitsubishi mini splits and another 5k on some rooftop pv. Then get a heatpump water heater too for about $1000. No plumbing, no pumps, and $ for $ you are getting the cheapest btu possible.

I just installed an extra mini split in my garage for this reason- it can keep it 60 degress when its 20 outside even with 2 9ft roll up garage doors leaking like a sieve. If it was bigger or unattached, or I didnt have $1500 to blow, I would have just put in a woodstove.

Solar is a great idea- but it has to be paired with ultra-high efficiency for it to be worth it. That is why the PV electricity + heat pumps work best, followed by thermal hydronic and air.

Here is a neat comparison of some high efficiency homes. We are starting to build them out of dirt again.

http://capla.arizona.edu/hed/docs/CivanoHomes2003.pdf

I have done a few 'normal' homes hitting 50cents per square foot per year, so I know 25 is possible. My house is down to about a dollar but it was built in the 50s with 2x4 walls.


At .10 per Kw electricity, one meter square of that solar collector is giving you 5 cents of heat per hour.
Compared to a 3-4 cop heat pump which would give you the same heat for 2 cents per hour.

Sorry for rambling- boring lunch break today.

It is sad news. But you did great attempt.. You will be able to make more efficient heat pump and become successful in future

[Dozyproductions]

I'd watch out. The government owns the sun's rays and heat just like they do rain water. Joking aside, smart house like this is a cool idea mate!

[Q5Quint]

We use geothermal on maybe 50% of our heat pumps in our area, but we are only below freezing a few days a year.