Archive for the ‘Energy’ Category

Jan 2016 Resolution thoughts

January 6, 2016

Using the analytic categories from last year about reducing my carbon footprint, here are things I’ve explored and directions for 2016.

Substitution. In December 2014 we bought a 2010 Prius to replace Krista’s 1994 Subaru Legacy. The change in mpg was from mid-20s to high-30s (most of her driving is in Moscow, it does better on longer runs on the highway using cruise control so it can do more of the thinking).

Our milage data shows her car drove about 7300 miles in each 2014 and 2015, the latter with a 50% improvement in fuel efficiency.

Replacement. On the other hand, my work has me driving around Moscow. I find that I need to get between places faster, or take things larger, than bicycling facilitates. That is, I can’t achieve the driving reduction behavior I want, so I’m thinking about replacing my ’89 Toyota wagon with a used Nissan Leaf and moving to a carbon free automobile. I drive almost exclusively in Moscow and occasionally to Pullman and rarely to Lewiston. It seems the Leaf will meet my needs.

 Year 2012 2013 2014 2015
Krista’s car (red) 7927 6313 7370
My car (white) 5241 2336 4472 4107
My pickup (blue) 1059 2078 1576  966
Krista’s Prius (silver) 7318
totals  14227  10727  13418 12391

In 2014 I gave away our 15 year old riding lawnmower/snowblower. For two years now I’ve contemplated replacing the remaining gas lawn mower (self-propelled walk behind) with a reel mower and/or an electric (corded or cordless) mower. I think a purchase needs to happen in 2016, even if I keep the gas mower as backup.  Key issue is storage, I need a way to put either of those devices away out of the weather.

More Substitution. Karina and I used a Kill-A-Watt to measure the energy used by our refrigerator (part of a campaign to get a new fridge). Over a 3-day period (73.75 hrs) it used 9.06 KWH for an annual rate of 1076 KWH/yr. Karina has found replacement refrigerators with Energy Star ratings and energy usage ratings as low as 466KWH/yr and multiple options below 650KWH/yr. Now, realizing that the rating is like an EPA milage number (your milage may vary), it’s still hard to imagine we can’t get a better performing fridge.

We pulled out the fridge, it was made in Aug 1998 (17+ years ago). Googling how long a fridge lasts we found 3 sources: 80% last between 9-15 years; 10-15 years; and average 13 years.

SO, owning a refrigerator for its lifetime has 2 energy costs: operational cost and construction cost. One is paid daily, one is paid every 10-15 years.

As an aside, I wondered if there were a fridge that would pay for itself in energy savings (compared to keeping our current fridge (if it would last another 15 years)). I looked up the Avista power rate and multiplied by the KWH savings/year of our current vs potential new fridge = $45/year.

Karina was reluctant to search for a refrigerator that was 18+ cubic feet, 450KWH/year and priced under $700, but she found one (I think). Her reluctance stems from a desire to buy the features in the more expensive fridges she has found– which maybe should be a new category for this analysis: Too much vs Enough.

However, the analysis raised another question. When talking about payback period, are we talking the best sale price we can find, or the suggested retail price? That is, what does price measure: cost of inputs or other intangibles in the merchandising process?

Generation. I regularly observe that the solar air heater is in operation in the Cookhouse. I have resolved to get its water heater running. I intend that project to be the pilot one, with the home water heating to follow. The Barn is partly ready for solar hot water and solar air heating conversions, but it will be the third project to tackle. The house uses gas for hot water, the Barn uses gas for both water and space heating, so I have several opportunities to reduce direct carbon use through generation.

2015 Resolution – Reflect on Conservation

January 3, 2015

Progress on reducing my direct carbon footprint

Following on my conceptualization for the solution to reducing my direct carbon footprint (this analysis), here is the year in review:

Reduction. I think my theme for 2015 needs to be reflection on conservation, and its nuances.

In previous New Years posts I have tracked our car milage and was pleased to see our progress reducing miles driven. Alas, the reduction was lost in 2014. The lesson: bike/walking to reduce miles in town is easily overwhelmed by driving out of town, which should be obvious, it takes quite a few avoided short trips in town to equal the milage of one trip out of town.

2012 miles 2013 miles 2014 miles
Krista’s car (red) 7927 6313 7370
My car (white) 5241 2336 4472
My pickup (blue) 1059 2078 1576
Prius (silver) new 12/4/14
totals  14227  10727  13418

My friend Stephen has a longer dataset and can demonstrate real progress reducing his driving, so it is possible.

spaeth carbon wedge car

In our cars, reduced use requires constant vigilance. In contrast, the area of lawn I mow is being reduced steadily by orchards, gardens and landscaping at the Cookhouse. I haven’t used the 15-year old riding lawn mower/snowblower in 12 months. Since, I’ve proven its possible to manage what is left without the rider, it needs to go away this spring.

Another notable experiment in reduction was to put a timer on our hot water heater. Now we make hot water for morning showers and again for evening dishes. While the savings from not maintaining hot water is small, we have proven in the past 6 months that we don’t lack for hot water when we want it. This experiment needs more study. For example, can we time the water heater so we use up much of the hot water and only store tepid water (rather than having the water heater reheat the water we just used and then storing that hot water)?

Substitution. Another of the strategies to reduce my direct carbon footprint is to substitute technologies.

The Cookhouse was built with all LED lighting and I thought I was done converting the Barn, but the other day I found one more CFL — a small one in a reading lamp. The house is partly converted, the Kitchen, family room and bathrooms are done.

My efforts at substituting LED lighting for CFLs are producing limited results; my home electric bill is not going down much (if at all), because the refrigerator, freezer, dishwasher and electric dryer are such a large fraction of the use that they overwhelm the savings in the lighting.

The used Prius that Krista will drive in place of the “red” car appears to give her 40+mpg vs the previous 25+mpg in “red car,” so if we can hold the miles driven steady, it should be a decrease in fuel used.

Replacement. The oven in our gas stove died last spring and (sigh) there are no parts to repair a 10 year old stove. The process of deciding has been slow, but we are headed toward an induction stove, all electric. The decision process was explored in this column. Replacing this appliance will produce a permanent decrease in our direct use of carbon, but a small one compared to the gas water heater. I’m having the electrician get me ready to do the water heater, but can’t afford that change yet.

While the 15 year old gas lawn mower is still running, I’m considering replacing it with an electric one. Since I’m not sure how that will work in when the grass grows fast in the spring, I’ll keep the gas one around for another season.

Generation. I have some more data on the impact of the solar air heater in the Cookhouse. My previous report was from a short duration observation. Now I have a year’s worth of data which appears to show April, May & June readings with less consumption than heating degree days would predict. Since the structure is still unoccupied the only energy use is for heating. Goals for 2015 are getting hot water preheating going in the Cookhouse and in our house. This data are also encouraging me to develop solar air heating to supplement in the barn.

849 electric usage

Electric heating in the Cookhouse for 2014

More data on solar air heater

December 12, 2013

The recent cold snap let me collect some interesting new data. Previously I had reported on temperatures in the building with the solar heat on and off, but that didn’t tell how much energy was being captured by the collector. At the end of that post I speculated on a way to approximate measuring the energy.

Each day during the cold snap I read the power meter at 10:30pm. The Weather Depot website gave me the Heating Degree Days for each day. (Heating Degree Day is the indoor temperature minus average outdoor temperature; a measure of how much heating is needed. Colder days have more HDDs.)

This gave me a table, and I could calculate a ratio HDD/KWH which should be a constant

HDD (55F indoor) KWH/day Ratio
52 62.44 0.839
42 51.32 0.824
33 39.75 0.825

The ratio lets me predict, knowing the HDDs, how much energy the building would use.

I turned the solar on Wed, and collected data. It was a fairly clear day, high haze but strong shadows. If the solar is effective it should save me energy, ie, reduce the KWH that would be expected to be used for a given number of HDD

It Worked!  The Solar heater came on for 4-5 hours. While I never saw the temperature inside rise above the 55F thermostat setting, I used 6 KWH fewer than the HDD on Wednesday would predict.

6 KWH is 22% savings – about 1/4 of the energy, which roughly agrees with the collector operating for 1/4 of the day. The building has no thermal storage, its like a greenhouse that warms up in the sun and cools again when the sun sets.

The water heater portion of the system is the way I will store energy. I hope to do a final system leak test on that system this Saturday.

First data from solar air heater

November 30, 2013

I have been making (slow) steady progress on the “Cookhouse” project. The utilities got installed over the summer by some great contractors: Nolan Heating, Jeff’s Electric, Don’s Plumbing, Jamin at Energylock for the spray foam insulation and Tom at Avista for the new transformer. I spent Sept-Nov working outside on the siding which caused me to need to get the solar air and water heaters finished up enough to put the glazing on.

collectors on the south wall. Air heater is the set of tubes at the top, water heater is below

collectors on the south wall. Air heater is the set of tubes at the top (above the scaffold deck), water heater is below (click to enlarge)

I built two things into one collector. The lower 12 feet is hot water (pre-)heating. But having watched the sun angles I realized that there were 5 feet above that which get winter but not summer sun. I made an air heater in that area. I suspect the air heating gets some heat rising from the water heater — I didn’t seal them off from one another.

The hot water system is inspired by this design and will be the subject of another post.

For the air heating, I did a variation on the “solar can heater”  I used pre-made ducts rather than messing with a bunch of cans. I have a fan that draws air from the upstairs ceiling, thru the collector, and blows near the floor downstairs (opposite flow from the illustration).

To control the hot air system, I installed two conventional thermostats. One is typical house heating thermostat (on when cold) and the other is an attic fan controller (on when hot). The combination (hot in the collector, cold in the house) turns the fan on.

When the electric and heating was turned on I hooked up the solar air heater. In late October I measured 172F in the collector, 60F air going in upstairs and 122F air coming out downstairs.

indoor and outdoor temps for experimental and control days

indoor and outdoor temps for experimental and control days (click to enlarge)

Last week I was able to do some more systematic data collection on two sunny days with similar outdoor conditions. Nov 21 was the experimental day, Nov 22 the control. What I found was that the heater can warm the downstairs by 10+ degrees F over the warming I get without the heater (just the sun in the windows and warming the south wall).

I need to get some better instrumentation to take more data, but that will have to wait for another post.


Footnote. I have been mulling over how to get a better measure than these temperature data, what I want is units of energy. Since the only energy use in the building now is heating, I can read the meter for KWH in a 24 hour period. I just found this site where you can get heating degree days (1 degree-day = 1 degree difference in temperature for 24 hours). Even better, you can control the indoor reference temperature.

SO, if I turn the solar off and pick a cloudy day, I have a measure of KWH/day and a measure of delta-T/day which will let me estimate the building overall R-value/day. I think I can use that estimate of R-value along with the KWH & degree-day for a sunny day to estimate the energy gathered by the solar system.

UPDATE 12/29

I made 2 of these manifolds to fit 9 3" duct. Duct material is 5 foot. Backing is 1.5" of TuffR rigid insulation painted black. Once installed the pipes were sealed in with spray foam.

I made 2 of these manifolds to fit 9 3″ duct. Duct material is 5 foot. Backing is 1.5″ of TuffR rigid insulation painted black. Once installed the pipes were sealed in with spray foam.


Inside view upstairs. Hole at top is air going out to collector. Light comes in because collector not installed. 4" duct below goes downstairs where fan draws air down.

Inside view upstairs. Hole at top is air going out to collector. Light comes in because collector not installed. 4″ duct below goes downstairs where fan draws air down.

This is a conventional attic fan thermostat (on when hot) set at 90F. This (plus indoor temp) decide when fan comes on to draw air thru heater.

This is a conventional attic fan thermostat (on when hot) set at 90F. This (plus indoor temp) decide when fan comes on to draw air thru heater.

What to do now about climate change

June 28, 2011

I had been hoping that the energy/ climate problem would somehow be solved by market economics (since national politics and international cooperation don’t seem anywhere close to addressing the issue).

But this study (PDF) by the University of Iowa on local vs conventional food gives me doubts. Their study found “…fresh produce transported to Iowa consumers under the conventional food system travels longer distances, uses more fuel, and releases more CO2 than the same quantity of produce transported in a local or Iowa-based regional food system.”  But it also concluded that ” … fuel costs will need to rise significantly if they are the only factor considered in determining whether local and regional systems are economically competitive…”

I guess I should have understood that transportation costs are a small fraction of food costs, why else would we have wine from Australia and strawberries from Chile.

Juxtapose that with the fact that the price of oil is high enough to make Canadian tar sands profitable and as Bill McKibben notes, they open “the first huge oil play of the global-warming era, the first time we’ve dangerously stepped onto new turf, even though we understand the stakes” (see this summary for understanding the stakes).

“Global CO2 emissions and warming compared to pre-industrial times for a scenario without climate policy (red) and a scenario in which the emissions are restricted to 1000 billion tonnes of CO2 (blue) from 2000 to 2050. The intervention can limit the probability of exceeding the 2°C threshold to 25%. (Credit: Image courtesy of ETH Zurich)” From

We have reached the fork in the graph above. From now on, its a zero-sum game. Globally, we can’t increase carbon releases, which, given rising population means we must reduce carbon per person. And, given rising wealth and consumption in developing countries, developed countries need to disproportionally reduce carbon per person to offset growth elsewhere.  Then by 2020 the planet needs to be reducing total emissions.

So what is a person, or a small town to do? We are faced with an instance of the Prisoner’s Dilemma. Economics (and hence politics) seem to favor the status quo, encouraging environmental destruction on a planetary scale. I can choose to eat local and low carbon, but my neighbor might not. I can choose to walk or bike, but my friend just bought a big pickup. We both go to hell in the same hand basket.

I think we need to be taking three kinds of actions now:

  • Strategic investment to reduce carbon consumption without deprivation (the low hanging fruit that simply substitutes greener technologies without larger life-style implications (eg a Prius)). Given the graph above, society needs to do this substitution fast enough to prevent an increase in the overall rate of carbon consumption.
  • Make long term choices that do not compound the problem by bringing forward high-carbon assumptions. The building patterns we establish now will be with us for 50+ years and need to be tailored to future less consumptive patterns. (see South of Downtown Moscow).  This also impacts how we design our aid for others (NYTimes login required).
  • Start playing with resurrecting knowledge and lifestyles from low carbon cultures (existing and historic) and understanding the technical requirements and social changes required to implement them today (see for example my experiments with a mud oven).

(Ending to this post rewritten 6/29.)



Returning to my energy conservation resolution

August 30, 2009

At New Years I had a reflective moment and resolved to work at reducing my carbon footprint. Best intentions got side tracked by the ever more consuming and ever more urgent task of getting Palouse Prairie School open. As the school turns the corner to opening Sept 2, I’m starting to think about new projects, and my thoughts are returning to my resolution.

While big projects and big spending are attractive, because they are big, my previous analysis was to work on the small projects, the many small energy leaks and wastes, and see what can be accomplished with small investment. Bob Hoffmann encourages me in this path with his periodic reports of lowered utility bills from changing out a bad basement window, insulating his hot water heater, caulking and other low budget tasks.

My explorations of the mud oven point to some potential for keeping unwanted baking heat out of the kitchen (along with some fun baking). The heating potential of the mud oven (using its waste heat in the winter) would require a larger construction project that’s beyond the scope of my small projects.

Step one, assay the situation. Where are we still using incandescent light bulbs? Get a blower door and look for infiltration leaks.

Next summer I need to re-roof the house. What conservation moves can get rolled into that project?