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SOLAR HEATING SYSTEM

HEATING ENERGY USED FOR MY WORKSHOP
SINCE 2001

 

I have kept accurate records of my propane deliveries for my well insulated workshop so that I can track the efficiency of my heating system.  Below is an annotated chart showing propane use, cost and notes.  I am rather pleased to see that I am continuing to reduce my fossil fuel consumption as I learn to optimize my heating systems.

The building is about 1260 square feet and the propane is used to automatically augment the solar heating system.  As the heat output from the 80 gallon solar storage tank drops below 140F a Bosch Aquastar propane heat on demand unit ramps up it's flame to maintain a 140F feed to the ground floor radiant slab and 2nd floor 10 ft. baseboard radiators.  The design goal for the solar heating system is that it can heat the building down to 32F on sunny days and below that I use propane and the wood stove. 

I also occasionally use a small electric heater to augment the 10ft. baseboard radiator in my 160 sq. ft. office on the 2nd floor.  I have calculated that if propane goes above $4.00/gallon that it will then be more cost effective to heat with electricity at our local cost of $0.14/kWh.

Since 2006 I have been using the wood stove frequently in the winter to reduce the cost of purchasing propane, on colder days I light 2-3 fires.  By burning wood in a clean burning wood stove from trees felled on my property (since 2010) I am just shortening the carbon cycle of the wood that would naturally decay and release carbon eventually.  So this is basically carbon neutral.  I harvest wood from our property using my cordless electric chain saw and split it by hand.  I harvest some standing dead wood and a large amount of fresh cut hardwood.  I use an electric chain saw because gas ones are gross polluters and just plain nasty, noisy machines, the power for my corded electric saw and cordless chainsaw comes entirely from our solar power system so is carbon neutral.

I installed a propane backup generator in 2008.  Power outages range from under an hour to over a week as a result of Maine winter storms and wind events.  I estimate that the generator uses around 20 gallons/day, so it can impact on our seasonal propane usage.

PROPANE CONSUMPTION BY HEATING SEASON
SEASON GALLONS
DELIVERED
$/GAL. $/SEASON FIREWOOD
(CORDS)
BACKUP
GENERATOR

(HOURS)
NOTES
2015/16 162.6 $2.03 $343.85 1 15 Mild winter
2014/15 218.9 $2.50 $592.00 1+ 54 Long cold winter
2013/14 193.2 $2.00 $429.61 1+ 7 Long cold winter
2012/13 180 $2.42 $435.87 1+ 40 Burned a lot of firewood
2011/12 210.9 $2.61 $550.21 1.25 8 Very mild winter
2010/11 444.1 $2.99 $1331.75 .25 67 Long cold winter! 
2009/10 267.5 $1.99 $534.82 .25 98 Warmer year
2008/09 301.7 $2.76 $832.69 .3 146  Colder winter, propane price surged .84 cents/gallon. + added propane generator
2007/08 409.57 $1.92 $786.38 .25   Warmer winter.  Installed heat recovery ventilator that is 87% efficient
2006/07 441.5 $1.99 $878.58 .2   Propane price jumped 50 cents!
2005/06 412.9 $1.49 $615.22 .1   installed wood stove and saved 147 gallons burning scrap wood.
2004/05 559.9 $1.41 $789.45      
2003/04 658.5 $1.29 $849.46     A cold winter
2002/03 691.25 $1.24 $857.16     Added 2 more 2X8ft solar collectors + bulk buy on propane
2001/02 771.52 $1.29 $995.27     Californian adapting to Maine and setting the heat high!




I created a chart of the heating degree days since 2006 using data from degreedays.net.  This helps to gain an understanding of the relative heating needs per season.  For instance,  the winter of '11-12 was warmer than normal, while '08-09 was colder.   Propane use does not directly track heating days due to my use of solar and increasing use of wood.  A sunnier winter reduces my building's heat load.

ART TEC Solar

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