February 23rd, 2008
|06:17 pm - Spring(ish) Planting|
Reposted from the new blog.
I called around yesterday to see if any place in the area had an auger that I could use when the fruit trees arrive. While I still have a vague sense that using a mechanical tool to dig the holes for the trees is somehow cheating, I've worn myself out two weekends in a row now trying to dig out the privet stumps that dot the area in which I want to plant. The auger rental is not terribly expensive - 75$ for the weekend - and the time saved may well be worth it.
That all aside, Elder Daughter and I had a good afternoon working in the garden. We extended the garden bed by another foot in width (east-west) and about 4 feet in length. This involved digging up and transplanting the grass, adding about a 40 lbs of mushroom compost, and then covering it over with a tarp to kill the remain grass and weeds. Then, we worked another scant 40 lbs of compost into half of the original garden bed and planted a row of radishes and a row of kohlrabi. We also mixed up compost and a little potting soil and filled several cell trays. In those, we planted more kohlrabi and radishes, to transplant into the new area of the bed later, and some of our flowers - zinnias, purple coneflower and statice. We also planted two different varieties of sunflowers into peat cups, since sunflowers don't transplant so well. The cell trays went under the new cold frame, since its a bit early for all but the radishes and kohlrabi.
Once we got all the bed preparation and planting done, Elder Daughter played in the sandbox and around in the backyard while I dug out two more stumps. What I didn't get done was sheet mulching the area in the west side yard that will become the flower bed. There'll be time for that later.
February 3rd, 2008
|12:59 pm - Porous streets|
Reposted from the new blog
After reading this post from WorldChanging, I wondered a bit about the wisdom of porous pavement. Sure, I understand the issues that are caused by stormwater runoff, but I'm a little concerned about what gets washed off the streets through the pores in the pavement.
There are probably good ways to handle this, including beds of Stropharia mushrooms on either side of the road to mycoremediate the waste water stream or even a filter layer underneath the pavement.
I also wonder what is actually underneath that pavement. Is it the sand and gravel bed that typically underlies roadways? Or is it something else more porous? The percolation through a layered gravel bed might reduce the pollution in the water that passes through.
January 20th, 2008
|10:01 pm - Upgrading from an oil furnace to a heat pump|
(Reposted from the new blog)
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.
January 19th, 2008
|10:53 am - This blog will move soon.|
I've set up a hosted blog on my Freeshell account using Wordpress. While I've generally been pleased with Livejournal, I've been looking for a way to separate out some of my more personal content and this looks like the best way to do it. I'll probably dual-post here and there for a while and then this LJ will likely have mostly friends-only content.
The new blog can be found at brentn.freeshell.org.
January 13th, 2008
|06:58 pm - Science fiction interlude|
If you're an SF geek like me and you haven't heard of them, I highly recommend the io9 blog and Steve Eley's Escape Pod podcast.
Escape Pod, in particular, is worth your time because Steve has a really keen eye for picking good fiction for the podcast, a keen ear for picking great readers for the stories, and a really great attitude about SF and podcasting.
Technorati Tags: escapepod, io9, SF
January 12th, 2008
|01:40 pm - Quote of the year|
I've been reading "What We Believe but Cannot Prove", by John Brockman. Its a compilation of short essays by some of the world's leading thinkers, covering that eponymous topic. One of the best responses comes from Seth Lloyd, professor of Mechanical Engineering at MIT.
I believe in science. Unlike mathematical theorems, scientific results can't be proved. They can only be tested again and again until only a fool would refuse to believe them.
I cannot prove that electrons exist, but I believe fervently in their existence. And if you don't believe in them, I have a high voltage cattle prod I'm willing to apply as an argument on their behalf. Electrons speak for themselves.
December 16th, 2007
|09:19 pm - The global energy budget|
Alternative, renewable, and sustainable energy is on my mind a lot these days. An awful lot. While I was at the Materials Research Society's Fall Conference in late November, I was fortunate enough to hear Dr. Stephen Chu's plenary address on renewable energy and climate change. One of the things that struck me about his lecture was his utterly upbeat attitude towards the problem and his optimism that we would be past this latest energy crisis and into an era of sustainable energy.
As energy goes, there are only a few ultimate sources . You can harness energy from solar radiation, from decaying isotopes, from the residual heat of the earth, and from gravity via the tides. Obviously, fossil fuels and biomass energy sources are merely ways of capturing and storing solar energy. Many of the proponents of solar power, whether that is photovoltaic or solar thermal power, claim that solar will ultimately be the most efficient and cheapest source of power to harness. I'm inclined to believe this assertion personally, although I do know that there are many interesting geothermal and tidal power projects under development.
As I have been doing my own study and research into this area, I thought about the limits of the problem. At our current state of technology, or really at any given state of technology, there is a finite amount of energy that can be harnessed. But even if you assume there is an evolutionary growth in efficiency of capture, there has to be some limit, some budget that you cannot exceed without a true step-change in the technology available for energy capture and storage.
So where is the limit here? For solar energy, there is clearly a finite amount of solar radiation available to the planet. Earth subtends a vanishingly small solid angle in the solar system; we cannot capture even the barest fraction of the Sun's output. The assertions I allude to above can essentially be rephrased as "the Sun sends enough energy to Earth to provide our civilization with enough power to grow for the indefinite future." I want to test that assertion and find out what the limit is.
Rather than computing the Sun's energy flux from first principles, which I vaguely recall having to do while studying for my Ph.D. qualifying exam, I resorted to the Intergovernmental Panel on Climate Change's Working Group I report, which gives the average solar flux as 342 W/m^2. (There's a great chart on page 4 of the linked pdf showing what happens to that 342 W/m^2.) Assuming 5.1 x 10^8 km^2 as a rough estimate of the Earth's surface area, this gives an total annual insolation of about 5500 zettajoules (5500 x 10^ 21 joules.)
Remember that number. That's an important number because it represents the total solar energy budget available to the planet. Within some margin of error, that's it for solar power.
Now, how much energy does the planet use? Ignoring the solar energy utilized by the Earth's biosphere and considering only the energy use by the human race, we find that number in a table published by the Energy Information Administration: 488.3 exajoules (488.3 x 10^18 joules) in 2006. The site also has historical information going back to 1980. From that data and the projected growth over the next 10 years, I estimated an average annual growth rate of 1.75%. This seems pretty low to me, but I'll stick with it for this calculation, since undoubtedly we'll get better at using energy efficiently. At 1.75%, the amount of energy the planet uses will double every 40 years.
Let's make some further assumptions, even though they won't really significantly affect the outcome. Let's assume that the limit to the efficiency of capture we can reach is 95%. That leaves us 5125 zettajoules. Let's also assume that the biosphere requires 10% of the solar flux. I have no idea if this is correct or not - the number I typically see for photosynthesis is 5%, so I'm adding a safety factor. This leaves us at 4675 zettajoules.
Now, do the division. 4675 * 10^21/488.3 * 10^18 = 9574. log2(9574) = 13.2. Therefore, there are 13.2 doublings before our energy usage outstrips the solar budget. 13.2 * 40 = 528 years.
This is a pretty hack calculation, to be sure, but the implication should not be ignored because I waved my hands in a few places. In less time than it took us to get from the Renaissance to the modern age, we will outgrow the solar energy budget. This is truly not a lot of time in a historical perspective.
What I believe this implies is that we need to be thinking about the next half-millenium right now as we work to solve the current energy crisis. There are ways to increase this budget. Geothermal and tidal power are two of them. Orbital solar power stations are another. These are within reach given our current technology. There may be other ways to capture energy that we'll discover over the next century.
But in order to do that, we have to not treat our energy technologies as "good enough." That sort of thinking after the Arab Oil Embargo and the energy crisis of the 1970's has put us in a state right now where we're really still only ramping up the development of non-fossil fuel technology. If we recognize that cheap, clean energy may not only be the solution to world climate change and pollution, but also to world poverty (I state this without proof, but there is some evidence to support the assertion), then it should be obvious that thinking beyond the next 20 years is necessary.
Technorati Tags: energy
December 3rd, 2007
|01:25 pm - A review of The Golden Compass|
Most times, whenever the Religious Right starts jabbering about boycotts, I simply roll my eyes and ignore them. This review of the upcoming movie based on Philip Pullman's The Golden Compass made me grin widely. I'm not usually a fan of movies that are based on books I've enjoyed, but I'll probably make an effort to see this one.
November 20th, 2007
|05:57 pm - The two toolboxes of innovation|
My buddy Ian Wilker, a social media guru, wrote a great blog post about how Twitter fits into the landscape of human interaction. One thing that he said that hit a chord with me was:
"...whatever abilities I have are less a matter of original thinking than they are of having developed a sensitive antenna for whatever the cultural — the hive mind — is exhaling. Twitter is one thing that makes this respiration visible."One of my colleagues and mentors at work is an incredibly innovative engineer. The most sage advice I have ever received from him is his philosophy of innovation. Essentially, he suggests that innovators have two toolboxes to fill. The first toolbox is the technical toolbox - all the things you know how to do. The second toolbox is your toolbox of interesting problems. In his view, if you keep filling your toolboxes with skills and problems, you will find opportunities to use your skills to solve some of these interesting problems.
To me, Ian's view of Twitter seems to jive with this philosophy of innovation. Twitter is a way to keep a look out for interesting problems. If you're aware of what is beginning to emerge from the constantly changing landscape of society, then you have the opportunity to meet it and develop yourself with it.
Technorati Tags: digital age, twitter, community2.0
October 28th, 2007
|09:37 pm - Pickled Kohlrabi|
With the first frost imminent (NWS predicts 31 tonight), I thought it a good idea to start harvesting the last of the crops from the garden. Chief on my list was the kohlrabi, of which I had seeded a second crop back in June. On a side note, I'll show this picture of the garden, in which I hope that the swiss chard's healthiness is noted. We have eaten swiss chard more than we have wanted to, given bunches away, and ultimately harvested somewhere between 20-25 good sized (i.e. larger than the grocery store) bunches from what I planted this year. And there is -still- more out there. And according to my friend Cathy, if I leave the roots in the ground, they'll come back next year. Wow.
I still have some of my third radish crop coming in, which will likely not survive the frost, and some green roma tomatoes off on the right. Lots of fresh basil too, on the lower right. A lot of the green in there is the red clover I've planted as a green mulch for overwintering.
The patches of bare ground were where the kohlrabi were - 4 roots the size of a large sweet potato and a couple of smaller ones. Looking through the possibilities, I decided to make kohlrabi pickles. Kohlrabi being, well .... kohlrabi, there weren't a whole lot of recipes out there. After poring over various recipes for vegetable pickles, I ultimately decided on the following pickling brine:
8 c. white vinegar
4 c. sugar
4 T. yellow mustard seeds
2 T. celery seed
1 T. cumin seed
9 bay leaves
I boiled and simmered the brine:
while chopping up the kohlrabi. I was afraid that the larger ones would be too woody. I was pleasantly surprised. They were still crisp and spicy. I chopped up a couple of stray carrots and about half a white onion, cut into petals, to go in the pickle as well.
Of course, I wanted some garlic in the brine as well.
At this point, I boiled the chopped roots in salted water for three minutes and drained them. Once the stove was clear of that, I began heating up the water in the canner.
I had my jars washed and ready to go and the lids warming in another pot behind the canner. I added about three cloves of garlic and a few onion petals to a jar, then filled it the rest of the way with the boiled roots. I then ladled in the brine, making sure one bay leaf got into each jar and leaving about 1/2 inch of headspace. A few of the jars got a teaspoon of red pepper flakes as well. After that, I tapped the jar around to loosen any air bubbles, lidded and screwed the rings down before moving on to the next jar.
The processing time was a bit of a question, given the different recipes I had cobbled together. I went with 15 minutes, to be safe. With the number of jars I had, I had two loads to run through the canner.
At the end of the process, I had a beautiful looking pickle. The lids all made the delightful little 'dink' that tells you that you've gotten a good seal and (hopefully) preserved the food properly.
Total yield: 9.5 pints. We'll be eating kohlrabi pickle for a while, I hope.
Technorati Tags: canning, kohlrabi