Visit to the NC Museum of Natural Sciences

This weekend, the entire family packed up and headed down the mountain for a visit to the NC Museum of Natural Sciences. I felt like I needed to share some of this experience with the world at large, because if you’re not familiar with the NCMNS, you are missing something special. For years, the museum was a solid and fun experience for myself, my partner, and the geeklings, the latter of which especially enjoy the skeleton of Acrocanthosaurus. With the recent completion of the Nature Research Center, the museum has become a real treasure. We made our second visit to the NRC and our first visit to the Museum’s “backyard,” the Prairie Ridge Ecostation. I’ll talk more about both places below the break.

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Notes from my Renewable Energy talk

As promised, you can click through here and get a list of resources that I used in putting together my talk and that you might find helpful in general. I appreciate the great audience that I had – everyone was really engaged in the subject and I’m glad that so many of you got a lot out of it.

There are a couple of points I want to reiterate. First is that I think that true wealth can only be measured in Joules, the unit of energy, and that access to energy is a key human rights issue. I also think that the current and coming energy crisis can be solved by breaking both design and technology constraints on our production and use of energy. Of these, I think that the design constraints are going to be hardest to solve.

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Shiitake logs

Last year, I had to have a dying hickory in my yard cut down. While I paid to have most of the trunk hauled off, I still have a pile of the limb wood. I had decided a while back that I would plug these logs with shiitake spawn and make shiitake logs. Its best to do the plugging after the last hard frost, so I waited until yesterday to do the work.


I ordered my plug spawn from Fungi Perfecti, a neat company near Olympia, WA. They’ve got spawn for lots of different strains of mushrooms, but I love shiitakes and shiitakes love hardwoods. The spawn arrive in a little bag like the picture on the right. The spawn themselves are small dowels, about 1.5″ long, with a spiral groove cut into the side. You can clearly see the white mycelia from the shiitake in the groove. There is also some grain in the bag as well, which I surmise are how the dowels were inoculated.

Shiitake plug spawn

I had ordered my spawn about a month ago, so by the time I pulled the bag out, there was plenty of mycelial growth in the bag, which you can see in the picture on the left as the white matting around the dowels. According to the instructions, this is normal and probably wouldn’t have been so bad if I’d used the spawn more quickly. Fortunately, no mushrooms had begun to bud, so I didn’t have to pull those off.

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When I started my small garden plot last year, I was appalled at the state of the soil. Looking back at the blog post, I didn’t say much about it, but I recall loosening the soil and discovering a thin layer of topsoil over greasy red clay. I worked some leaf compost into the plot and went from there. I also noticed that in digging up the roughly 80 square feet of garden, I found only a couple of earthworms.

At the end of the growing season last year, I seeded the plot with crimson clover as a green mulch and leaf mulched the swiss chard in hopes of having some of it survive the winter. This spring, when I started planting, I noticed that the soil seemed much healthier – black and a bit deeper, and nicely crumbly. Most excitingly, when I was digging up some of that weird 6-leaved running ground cover that had crept in from the edges, I found that I couldn’t lift a spade of soil without turning up at least one earthworm. Fantastic!

In Chicago

I’m in Chicago this week on business. Things started off with a cancelled flight for both me and one of my teammates (two separate flights). Then, our first trial completely bombed, forcing me to revise the experimental plan somewhat. And to top it off, the 4th guy on the team who was coming had 3 flights cancelled or delayed, making him 24 hours late. Go Chicago-O’hare!

We’re up and going now and I’m sitting in the lab working on a new model for the data we’re collecting while I watch the equipment run.

Upgrading from an oil furnace to a heat pump

Last fall, when I was at MRS, the 40 year old oil furnace that had heated our home finally died. The diagnosis: cracked heat exchanger. We’d discussed this possibility a few times, trying out some scenarios. At the time of the incident, our current thinking was either a high-efficiency oil furnace capable of burning biodiesel or a heat pump. The folks at McNutt Service Group, the contractor we decided to work with, quoted us around $4000 for the oil furnace and about $6300 for the heat pump. The heat pump we had selected was a slightly above-average Trane model (16 SEER, 9.0 HSPF), which (along with the new air-handling system) we felt would give us the best deal in terms of efficiency and cost. After much debate, we decided to go with the heat pump for a variety of reasons. the most salient of these was the operating cost. I ran some rough numbers and estimated that over a 20 year lifespan of each unit, I should save around $6000 using the heat pump, based on a 3% per year increase in the cost of heating oil and a 1.5% increase in the cost of a kWh of electricity.

After receiving my first electrical bill that included a full month of the heat pump, I realize I may have underestimated the savings. The amount had only increased by about $35. At first, I thought that this month might have been warmer than usual, and in fact there were some warm days in the month. There were also several nights of temperatures in the teens. The National Weather Service’s climate data page did not indicate that the highs and lows during the month were excessive in either way (average temperatures 3-5 degrees above normal in December and a roughly equal number of days above and below in January.) With that, I was reasonably satisfied that the bill represented a typical January bill. A quick check back through my financial records showed me that from Oct. 2006 to Oct. 2007, I’d spent $766 on heating oil.

Going back to my spreadsheet, I plugged those differences in. Still not trusting the $35 number, I assumed that over the 6 month “winter” period, I’d average $50 more a month, for a total of $300. This number I assume is the cost of heating with electricity. Plugging in the growth rates I mentioned earlier, I set about determining my time to payback over an oil furnace. It’s less than 5 years to save the $2300 difference between the two units. But this really isn’t a good comparison – the new oil furnace would be much more efficient than the ancient Lennox furnace we had. The oil furnace we were quoted on was 90% efficient. Though I don’t have the numbers for certain, I’m estimating that the old furnace was no more than 70% efficient. Using that to adjust the cost of fuel oil, I recomputed the time to payback and got 7 years. Still, not bad at all. Assuming the growth numbers hold, I’ll save around $9000 (in today’s dollars) over the lifetime of the heat pump. And this doesn’t even count the savings in the summer of the 16 SEER heat pump over the old 11 SEER air conditioning unit that came with the house.

Bottom line for us was that the heat pump is looking to be a very good investment. And if folks like Nanosolar make it ultra cost-effective to put photovoltaics on every roof, the heat pump will be an even better decision.

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