Seasonal conversion of batch water and hot air

[Dave B]

I live in the Northeast with serious Winters. I was wondering if anyone converts their open loop batch hot water system to hot air convection for room heat in the Winter ? It seems like this could possibly be made to work so as to avoid the higher cost of a closed loop hot water system. Just thinking,  Dave B.

[Drives]

Dave:

I live in Central NY, similar to you.  I pass by your area a few times each year on business, but have been to busy to swing by.  I really enjoy your log "Mansions"!

If I ever get the time, my plan will be to have a "Summer/Winter" switch for my heater loads.  

Meaning, summer time I heat my hot water with my windmills, and winter time I switch to hot air convection for the back part of my house.  

In winter, I plan to supplement my hot water needs with a hot water coil off the wood stove, and the back part of my house is currently set up with electric heat anyway.

I believe Zubbly is "air heating" this winter with his new Gennie.  Hopefully he will comment with his experience so far.  

My biggest project is to build a simple, robust PWM heater controller. I have a neat circuit which allows the cubic function to be adjustable for each particular windmill's chacteristics....works great on paper!  (famous last words) ;-)

Next year I plan to erect a large 4 meter windgennie.  Right now I only have a couple of small (8' & 5') machines that were built to educate me.  

Many projects, very little time.

(got your snow tires on yet...the folks in Buffalo needed them)

I have enjoyed watching your projects, thanks.

[GaryGary]

Hi,

There is no reason that would not work as long as you can run a supply and return duct to the house easily.

If the glazing area on the collector is (say) 40 sqft, then, on a sunny day you might deliver about:

   (40 sqft)(1600 BTU/day-sqft)(40% efic) = 26000 BTU to the house

This would be the equivalent of nearly half a gallon of propane burned in a 70% efficient furnace.  Worth about a dollar around here.

You would probably need a small blower, which could be controlled by a thermal snap switch like the ones used on attic ventilation fans.  Home Depot sells replacement thermal snap switchs for about $15.  When the temp in the batch heater goes above the set point on the thermal snap switch, it turns the blower on.  You could set it for about 80F.

You could also have a look at other easy to make solar air collectors, and see if one of them makes as much or more sense.  We are going to have a go at adding removable  glazing to our porch so that we can get some winter house heat from it, and to make the porch useable in the winter.

Some DIY air and water collectors here:

http://www.builditsolar.com/Projects/SpaceHeating/Space_Heating.htm

Another option for your batch heater in the winter would be to add an insulated cover that would be opened on sunny or partly sunny days, and closed nights and cloudy days.  This should be capable of making some hot water all winter, but not nearly as much as it does in the summer.  If you try this, its important to make sure the plumbing lines to and from are very well insulated, as these are the vulnerable places.  You can also make the inside surface of the cover reflective so that when its open it reflects more heat into the batch enclosure.  Like the "Maine Solar" one listed here:

http://www.builditsolar.com/Projects/WaterHeating/water_heating.htm#Batch

The free Bainbridge book at the same link also has some winter batch designs.

Gary

[Drives]

Wow...I'm an idiot, sorry.  I should have looked at the area this was posted...SOLAR.  I was talking about wind gennies, I apologize...I need to read first!!!

[Dave B]

Thanks Gary & Dean for your comments and suggestions. I put this in solar as I have little experience with solar as of yet but my previous and current project is pre-heating water with my 12' genny @ 85' on my tilt tower. That is soon to be an 18' where now after experimenting and getting most of the bugs out I realize at times this size in my area should be able to provide useful quantities of hot water on good days (and nights) and pre-heat over time on the low wind days. I really like the idea of using hot water storage as my "batteries" and so the interest also in solar batch heaters etc. I use hot water everyday directly and stored can be used for heat besides. Solar to heat water, wind /electric to heat water, it doesn't get much more efficient and cost effective than this. I would appreciate hearing from anyone with solar / hot water set ups of any kind. I am most certainly in a full Winter freezing zone though. Thank you,  Dave B.