Monday, July 14, 2008

Energy Independence Week, Day 6

Wednesday, July 9, day 6 of Energy Independence Week

In the morning the batteries were down to 12.3 v.  It seems to take almost a quarter of the battery capacity just to run the 5 watt compost bin fan all night.  The icebox was hanging in there at 43.5 degrees.

Cold cereal for breakfast again, and then it was off to weed and mulch the potato patches.  By 6:30 the cooler was up to 49 degrees, and all the two-liter bottles had thawed, so it was just the three blocks left.  It looked like there was a storm coming so I hustled down to the river for my daily swim.  On the way back I decided to cheat and buy some more ice at the gas station, two five-pound bags.  So the original charge of ice lasted six days seven nights.  I barely made it back before the rain started.  

I joined Flora's expedition to Farmer Dave's U-pick Strawberries along with Ranger K and young Skyler.  So, dinner was basically rain-washed strawberries off the vine.  That was nice, as was the rainbow which was so bright it almost touched the ground in front of the treeline.  Farmer Dave's mosquito herd made such a good living off me I started to wonder if his U-pick deal was a scam to produce a sustainable yield of mosquitos.

I've been meaning to mention how well the cottage is working temperature-wise throughout the spring and summer.  The space heater gave up the magic smoke back on June 5, when the daily average temperature was still well below room temperature.  I haven't needed any active heating or cooling since, nor even any fans.  I've been able to manage the temperature just by opening and closing windows.  The passive-solar overhang on the attached greenhouse is a key feature - back in the spring when the sun was lower in the sky it would shine into the greenhouse and I could pump heat into the house just by opening the connecting door.  I don't mind it warm so I would heat the place up to almost 80 during the day and let it cool off at night.  Now that it's summer I'm opening the windows at night and closing them during the day.  I was using the ceiling fan a lot during the spring but I shut it off for Energy Independence Week and haven't missed it.

There is maybe some controversy about whether thermal mass is useful in this climate.  The argument against goes something like this:  Many of the natural building methods feature thick heavy walls with lots of heat storage. But a lot of that comes from the desert southwest where the main problem is not the average outside temperature but the extreme day-to-night difference.  But in central Minnesota it can easily be cloudy for say the entire month of November, and it would take a ridiculous amount of storage mass to ride that out, something like full earth sheltering which nobody dares because it's so outre it has no resale value.  So forget thermal mass, build it light and very tight (like passivhaus.)

I was pretty sympathetic to this argument but I have to say from living in this cottage it is nice to have the massive walls.  At the Midwest Renewable Energy Fair there was a workshop on the subject.  The presenter argued basically that in the spring and summer in Minnesota, the heating and cooling problem is in fact a daily moderating problem, as in the desert, so thermal mass is useful in this climate for a good portion of the year.  

In other news, the experiment plots are showing some noticeable differences.  There's a pretty bright line between the all-compost plot and the compost-sawdust mixture.  Here's a couple of views of that.  The all-compost plot is basically to the left of the white door on the cottage there.

The compost-sawdust mixture is right now not even as good as the chiseled-but-unamended control plot, and the sawdust-only plot has only a little bit of stuff growing.

It didn't photograph that well but the left half of the picture is the compost-sawdust plot and the right half is the sawdust-only plot.
Here's the control plot:

The crater has developed a more verdant patch, on the north side east, closest to the piles of dirt that were pushed in to fill it.  There is some different stuff growing there but it looks to me like its just more fertile on that side.  

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