Documenting my attempt to cut my energy usage in half.

Thursday, February 24, 2011

My Half Project

Gary Reysa over at BuildItSolar had several articles published in Mother Earth News and Home Power Magazine several years ago about his Half Project to cut his energy usage and green house gas (GHG) emissions in half.  He has managed to do this and more without making any major changes to his families lifestyle.

Reading through what he has done has got me wondering where I'm at.  I'm not sure I can do a half program because there are a lot more options for providing solar energy to heat a house during the winter than there are to cool a house during the summer.  However, to understand where I'm going, I have to know where I'm at and where I've been.

I retrieved the data for the last 6 years worth of electric bills and totalled up the kwh usage for each year. My house has a ground source heat pump to provide heating and cooling so I didn't need to figure in any propane, natural gas, or heating oil usage.  I did calculate the fuel consumption for the three vehicles, however I don't have a way of finding per year mileage so I ended up taking the total mileage on the vehicles and using that to calculate a per year average.  I know this isn't perfect as my mileage has dropped off a bit in the last two years but it's a reference point.

I'm not sure how these numbers compare to other houses in the area with similar square footage and all electric for heating, cooling, cooking.  I've found gvmt estimates for electrical usage per house but that includes houses that use some other form of energy for heating/cooking other than electricity.  What I haven't found is a chart of household or per person energy usage that includes all sources of energy.

My household uses on average over the last 6 years:  75,133 kwh/year
Per person average:  25,044 kwh/year

I was also interested in knowing how many tons of CO2 I'm belching into the air each year.  To do this I need to know where my electricity comes from.  The EPA was kind enough to provide this.

From that I was able to get this information on emissions.  Note that this is just from the energy used by the house.  This does not include emissions from my vehicles.

To calculate the emissions from my vehicles I needed to calculate how many gallons of gas I use each year.  From my earlier calculations for energy usage I determined that I drive on average, 15,336/year.  I also average about 18 mpg across all three vehicles.  That gives me an average usage of 852 gallons of gas/yr.  Each gallon of gas produces 19.4 lbs of CO2.  852 * 19.4 = 16,528 lbs of CO2.

CO2 emissions of 53,265 from electricity + 16,528 from fuel = 69,793 lbs of CO2.  That's the number I need to reduce.  I realize that this is not going to be an overnight change.  Gary has made significant reductions in his GHG emissions but over 6 year period.  If I can knock of 5% per year I will be very pleased.  I also understand that some changes that I make up front may have dramatic affects and that improvements in the years following will be more difficult.

Tuesday, February 22, 2011

Fighting the TED

I'm not sure what's going on with the TED 5000.  Soon after I installed it I tried setting up the load profiling and noticed that for multi-stage devices like my heat pumps it has a very difficult time determining when the device is on/off.  So I gave up on the heatpumps and decided to just look at the water heater.  I figured the easiest thing to do would be to manually enter the load data for it since I know what it's going to be (5500).  After doing that, the Load Profile tab would correctly show if the water heater was on or off, however, the historical data portion of that page always showed "No Data".   I thought that maybe manually entering the load was causing a problem so I turned off the water heater, took a quick shower, started the load profiling, and turned the water heater back on.  It took about 10 secs for the load to be "learned".  After a day of running with the learned profile, I still have no historical data.

I called Energy, Inc since their forums are offline (it appears they didn't renew their domain name) and managed to get a support person that has "never played with" the load profiling. After chatting with him and one other support person, it was determined that they've never heard of this issue before and suggested that I upgrade to the latest firmware.  Since that will wipe all monthly historical data, I'll have to wait until first thing in the morning on the day my billing cycle starts.

I need to get this figured out and collect some data now so that I can see how much the water heater comes on (or doesn't come on) when the ground source heat pumps are heating the tank.

Sunday, February 20, 2011

Lacrosse EA-3010U Handheld Anemometer

I bought an EA-3010U the other day to help with calculating the CFM output of the recently completed solar air heater and have mixed feelings about it.  I was able to get the readings from it that I needed but it definately doesn't work as well as advertised.  The manual says that it will read as low as .4 mph and I highly disagree.  My unit requires a fairly strong gust to get it spinning, in the range of 6-7 mph or more.  I've been outside in 10 mph winds before and have not been able to get the blades to spin to get a reading.  This is not a battery issue, it's a blades not spinning issue.  If I blow directly on the blades I can sometimes get a reading starting at around 3 mph but the blades will abruptly stop spinning as if they hit a sticky spot.  No where near the .4 advertised.

I have attempted to contact their support.  Email is their preferred method of contact which is good since they don't have an 800 number.  At least they are upfront about the fact that it will take a long time for them to respond.  Clock is ticking at 5 business days so far.

Update: Sun 2/27/11.  The unit is being sent back to Amazon because it doesn't work as advertised and Lacrosse support has failed to respond to my email.

Thursday, February 3, 2011

Solar Air Heater

I've been working on building a solar air heater for the shop to help reduce the amount of kerosene I have to burn to keep the shop warm.  The build of this was started about the time I found out about the Yahoo Simply Solar group and before I saw any of the testing results for different designs of solar air heaters.

The heater is based on a soda can design that I found here.  After doing a lot of reading during and after the construction of this, I believe that there are several designs that are better performing and in some cases, less expensive to build.  Those designs include the screen, downspout, and vented soffit.


Based on calculations for solar performance from built-it-solar, the collector is putting out about 3600 btus/hr at an efficiency rate of 43%.   I had to adjust the value for the density of air from the examples as they are based on a high elevation and I'm at sea level.  I ended up using a value of 0.075 based on this information.

The snap disc controller turns the fan on when the temperature reaches 110 and off when it drops to 90.  On a typical sunny day the fan will run for about 4-4.5 hours.  Starting at 10:30 and going off around 3.  There is one tree that partially shades the unit at around 2:30 and the fan will sometimes turn off then.

It's possible that I could get a little bit more run time out of the heater (by it starting earlier in the morning) if I had mounted it at a slight angle instead of flat against the building.  As mounted, the unit is facing 18 degrees west of due south.

One of the downfalls that I see with a can based collector is the huge pressure drop that occurs as the air tries to make its way through all of the cans.  For optimum performance the heat needs to be removed from the cans as quickly as possible to prevent heat from radiating back out through the glazing.   The low air flow can probably be solved by using a blower fan instead of an axial fan, but that increases the cost tremendously and the problem can be solved by a better collector design.


The 4x8 box is made of 3/4 x 4.5" oak.  The back is a piece of 1/8" plywood and is just there to prevent racking of the box.  The inside of the box is insulated with 1/2" polyisocyanurate with the foil side facing the inside of the collector.  This was not painted black as I have seen done in a few other builds.  The manifold at the top and bottom of the collector is ~6" high.  One thing I wish I had done differently is the cover for the manifolds.  It is currently a piece of black painted plywood insulated on the inside.  This should really be a piece of black painted aluminum flashing and not insulated so that the manifold areas can function as extra collector surface.   As it stands, only the cans act as the absorber plate for the collector with a surface area of 28 sqft.

The cans take a lot of time to prepare.  There are 17 columns of cans with each column containing 17 cans for a total of 289 cans.  The cans had the top/bottom cut out to open up the can as much as possible.  A v-trough made from some scrap 1x6 was constructed so that the cans could be aligned and sealed together with silicone.  The cans were then cleaned and painted with flat black high temperature grill paint.  Note that although most cans look the same, they all differ ever so slightly and that difference added up over 17 cans leads to differences is the lengths of the stacks of up to 1/2".

The fan I used is a 124 cfm axial fan.  The dimensions made it difficult to work with and I ended up having to make a mounting plate for it that was fastened to a 6" to 4" reducer to feed into the inlet side of the heater.  It's a good thing this is in the shop as aesthetic wise, this would not pass the "wife test" for being installed in the house.   The glazing is 8mm twin-wall polycarbonate.  I think it looks better than the single wall corrugated panels but it does add a bit to the cost.


Wood for box, back, manifold:  free, salvaged
Cans:  free
Twin-wall glazing:  $90
Silicone:  $10
Paint:  $15
Fan, snap disc controller:  $50
Wire, ducting, screws/etc:  $25
Insulation:  $10

Total:  $200

UPDATE Jan 2012:  There is a now a screen based collector #2

Tuesday, February 1, 2011

Heating the septic tank

The TED 5002-G that I installed in early Jan has got me thinking about a lot of things.  The other day when taking a shower it dawned on me that all that money I spent heating hot water really did go right down the drain.  It takes < 5 secs for the water to leave the shower head and enter the drain at which point all it does is heat the septic tank.  There must be a better way!   If only I could recover that heat to preheat the cold water going into the water heater.

I got online later that day and found a graywater/drainwater heat recovery product.  The GFX website is web design hell, but it or a product like it should be required by code for all new building installations.  Lord knows the builders aren't going to install it just because it should be.

Green Gate Guest House has a really good article on the one they installed.