A passive house in Karuizawa

Another passive house in Nagano prefecture, this time in the much cooler city of Karuizawa. There are some great points in this interview. One interesting comment is about the trade off between the high installation and low running costs of low energy buildings, compared to the lower initial cost and higher running costs of buildings using fossil fuel energy. Since most people borrow money from the bank to build, the actual initial costs to the owner of the house are very low, since the bank will pay for them. Effectively there are two sets of running costs: utility bills and loan repayments. Since people in Japan can often get low-interest 35-year loans, the loan repayment is a fixed cost. On the other hand, the utility repayments, at least the fossil fuel component of them, seem very likely to rise for the foreseeable future. 

https://catforehead.wordpress.com/2014/10/31/passive-houses-a-conversation-with-kevin-meyerson

I've already built the charger for my electric car

Thanks, Sam, for sending this article about the impending and inevitable replacement of fossil fuels with solar based on the ideas of business lecturer and entrepreneur Tony Seba. The argument in a nutshell is that fossil fuel extraction is becoming more difficult and so more expensive, while technologies in solar panels and batteries are getting cheaper. These trends will continue and at some point the current situation where petrol driven cars perform better than electric cars will flip, so electric cars will be cheaper.

At first there will be a few early adopters, paying higher prices for the new technology - like now in fact! Then prices will approach parity. Soon a critical mass will be reached, and economies of scale will further lower costs of the new technology. Since the price falls are exponential, the old technology will very soon be confined to small groups of wealthy fanatics.

So when will this happen? "By his forecast, between 2017 and 2018, a mass migration from gasoline or diesel cars will begin, rapidly picking up steam and culminating in a market entirely dominated by electric vehicles (EV) by 2030."

Note the expression "picking up steam" in this quote. I read straight through it the first time, but on the second reading it raised a smile, as it is using a metaphor from one obsolete mode of transportation to describe the transition between another two. It also somehow reinforces what Seba says about the speed with which technologies change.

Swift technological change is certainly possible, and I remember our electrician saying that LEDs were a waste of money when we were starting to build our house, but everyone nodding when the architect was boasting about "his" decision to put them in as he was showing people around just before we moved in.

The example of digital cameras is given in the article, and here there are similarities with electric vehicles. Traditional cameras need to be constantly fed with film, just like conventional cars need to drink petrol. Early digital cameras had low resolution and short battery life, but the technology rapidly improved and today they totally dominate. Kodak went from photographic giant to bankruptcy in about ten years.

Of course not everyone believes in this inevitability, but they are probably wrong. I remember a story recently about the problems Nissan was having with batteries for its electric vehicles, told with a strong editorial line that electric vehicles are a doomed fad. We have to be careful with new technologies though, and not mistake the signs. Just like Kodak, dominant powers of previous technology regimes may not survive and when they make mistakes it does not mean the technology is wrong. Polaroid were early pioneers in digital cameras, but it did not save them, and although Apple are now suppliers of many de-facto digital cameras, their early attempts at the technology failed. Even among start ups there will be losers as different parts of the technological jigsaw puzzle  jostle for their place in the big picture.

So the future trinity is likely to be solar panels on the roof, and batteries for the electric car. I'll let you charge your EV from my solar panels if you let me charge mine from yours!

Eco friendly fridges

However eco-friendly your house is, according to this report, what's in the fridge can make a big difference.

diets_effects_on_emissions_give_food_for_thought

The variable rate hasn't varied for 5 years...

Talking of future-proofing...

I have a fairly good grasp of mathematics, but my understanding of numbers dissolves away when you start putting currency marks next to them. 

Our land loan has reached the end of the five-year fixed rate we signed up for, and we have to decide what to do next. 

If we do nothing, it defaults to a variable rate. Alternatively we could go for another five-year fixed rate, or a ten-year fixed rate. I just got a phone call from the bank, and heard some percentages--I think I heard 1.5% and 1.7%--but I really need to sit down and look at things in writing.

According to this website, the current floating base rate is 2.475%. In fact, the flexible rate has been 2.475% since February 2009. That dark blue line is not part of the grid, it is part of the data.

Is that some kind of joke? Isn't variable supposed to mean that it can vary? 

It looks like we would have done better getting that rather than the five-year fixed rate. 

I know past results are no indicator of future performance, so just because the floating rate has stayed the same for the past five years doesn't mean it will stay the same for the next five years. 

Whatever we do will probably be wrong. Going for the fixed rate seems the most sensible approach since we may be losing out, but it will be by a predictable amount from each month's salary. The risk is much less than going for a floating rate loan, and suffering an interest rate hike. 

The ten-year fixed rate is at a historical low of 2.9%, which surely means something. The rate the bank charges is a little more than 1% less than this. Of course the numbers don't know the history, and they are probably just as likely to keep going down. As long as interest rates stay above zero, the banks will still be winning.

On the other hand, talking of risk, perhaps we should leave it with the flexible rate. This would then cause the interest rates to go up, which would be connected to increased inflation, which would in turn mean that the value of our loan goes down, and we would be owing and paying less in real terms.

Future proofing

Note to self: never add dates in the future when posting stuff on the internet. "No more till September" turns out to have been "no more till late October" and I should really have know that. Unfortunately I haven't been on extended holiday.

Other bits of life have caught up and I will make no promise about regular posts in the future. Past performance is no guarantee, but certainly a good place to start reading. You may even find some working pictures too. Just hit the calendar below and pick a date. Better still, try browsing by label, or even put a keyword into the search field.

I may write something about Japanese power companies turning down applications to sell them solar power. And I may write something about Glasgow university's plans to divest from fossil fuels. Or I might not. You'll just have to wait and see!

Carbon-free and rent-free

Anyone fancy a move to Cambridge? Not only carbon-free but also rent-free.

http://be-zero.co.uk/

They are looking for a family with at least two children to live in a zero-carbon house for a year, starting before Christmas 2014.

I imagine this will be heavily over-subscribed!

No more till September

I had had ambitious plans to load up several new and old posts so there would be an uninteruppted stream on the blog. I was going to send the fifty half-written emails in my draft box, but of course most of them are just a half baked idea in the title without anything solid to back them up, or solid titles undermined by half baked prose.

So pretty much the same as what usually gets published. 

And I was going to go through the archives and re-publish from the beginning, but even that would have taken more time than I have had.

But it hasn't happened, and now it probably won't happen. Not until September when I get back from my travels. 

I'd like to be sending messages from the yacht, telling you how nice it is to be our of email contact, but of course I'll be out of email contact. 

Five stages on the slippery slope

Sometimes it just seems like you're not going to make it. You look at all the things you need to do and the time you need to do it in, and they just won't fit. You add up all that you need to spend on all the things you need to buy, and it's more than you're going to earn--there is still some month left over at the end of the salary. Like you're heading straight towards a cliff with no sign of slowing down and no chance to change direction.

That's how it seems every time I start thinking about the climate. Too many centuries of carbon is being taken out of the earth each year, and the pressures of the population and excesses of the economy seem too great for this to get any less. The corresponding levels of carbon dioxide in the atmosphere have unthinkable consequences.

I know that carbon dioxide is a naturally occurring chemical, and if you look far enough back into pre-history you find it has been at much higher levels. I also know that this was a prehistory that humans did not live in.

The amount of atmospheric CO2 we have now just exceeded 400 parts per million, and I know that figure seems pretty small, and is not hugely different to the level of 350 ppm that scientists have said is safe.

In fact they both sound pretty small numbers. How could a gas making up such a tiny part of the atmosphere make any difference?

Here's a list of highly toxic gases. These will kill within an hour at 200 ppm or under.

Chlorine is lethal in one part per million, so a safe level of 350 ppm is starting to look pretty good, and 400 isn't such a small number after all.

And you may be thinking that the 2 or 3 degree rise in global temperature is no big deal. But what if it was your body temperature?

So you could really start worrying about this stuff. But you don't have to. There is another choice.

It's called denial.

Why worry, when you could bury your head in the sand and pretend it will go away?

There are five simple stages. Take your pick! Or why not start at the beginning, then you can work through them one by one?

• Stage 1: It's not happening
• Stage 2: It wasn't us
• Stage 3: It's not a problem
• Stage 4: We can't do anything about it
• Stage 5: It's too late!

Global warming denial has a history all the way back to 1991, according to this report in the New York Times of the coal industry trying to turn the fact of global warming back into a theory.

If you have an election coming up, look out for the party that is playing the global warming denial card. You know it makes sense for them, if they are really desperate. There are plenty of people out there who don't want to believe. Electioneers need to reach out to that demographic! And it makes sense for you too, as you feel there is some authority behind your disbelief.

Read more about it here at rationalwiki.org.

“Plot idea: 97% of the world's scientists contrive an environmental crisis, but are exposed by a plucky band of billionaires & oil companies.”
—Scott Westerfeld

Global warming - time to take the gloves off

There's something very funny about this picture. I'm not sure why, but when the left uses comedy to attack people on the right, it comes across as being very funny, with some underlying truth and justice. When people on the right use comedy to attack people on the left, it just doesn't seem to work.

This picture is funny, but not in the way it is meant to be. In fact, I think deep down it is not meant to be funny, and that may be the difference. The left is in a constant state of struggle against authority. Even when the left becomes powerful, it must struggle against itself and the inherent evil in the corruption of power, and the absolute corruption of absolute power. This is essentially comedy. The right, on the other hand, is dealing in tragedy. Their desire, their goal, and their destiny is to stay in charge. They are ultimately the victims of their own actions. And so are the rest of us. So if you're on the left, you can laugh. In fact, you have to.

Anyway, there is a serious point behind this joke with it's pyrrhic victory at getting a laugh. Not that Obama is setting out to kill the all-american bird. That idea is probably what makes this funny, in a kind of tragic way.

The serious point is that wind turbines do in fact kill birds.
In 2009, Electricity company PacifiCorp had to pay a $10.5 million dollar fine for killing 232 Eagles and other protected species.

Oh no, that was from electrocutions on power cables. Nothing to do with wind power--just supplying electricity from coal and maybe even nuclear power stations.

The avian fatalities from wind turbines are a little more modest, but even so they are significant.

You'd think that birds would have to be really stupid to fly into wind turbines. Those gracefully sweeping blades look easy to avoid. In reality though, the tips are moving at a very high speed, causing vortices that can disrupt birds' flight. I won't go into the Reynolds numbers here though.


Of course when it comes to Eagles, and especially the balding variety, we are talking about protected species, who probably are stupid. If they were so good at survival, they wouldn't be in the sorry state that humans are trying to help them.


Designers are now working to make turbines that will not affect birds, but this may be one more of those examples of taking the option with the least damage. We can continue with fossil fuels, and risk wholesale damage to the climate. Or increase carbon-neutral generation and kill a few pretty animals. There is no black and white in this, just shades of green and grey. Wind generation still looks pretty green if the choice is between killing a few pretty animals, or irrevocably changing the climate and killing many pretty animals.


I wonder how many birds are killed directly by pollution from thermal power plants? And what about all those canaries down mines?

And if you're worried about birds being killed in turbines, how many birds get killed by collision with aircraft?

Meanwhile, the state of Schleswig-Holstein in Germany has reached 100% renewable generation, mostly from wind.

The German eagles are evidently doing alright.


(Let me apologise, too late, if anyone found my earlier comments eaglist. In future I will try to be eaglitarian.)

Using large pipes as rainwater storage

In this interconnected age, whenever you have a great idea and start googling it, you usually find that somebody else has had the same one. In fact, you often find that somewhere there is a lively forum dedicated to implementing that idea, with five-star experts who have been sharing their experience since before the internet was invented.

So when you do have an idea and can't find anyone else who has done it, you start to wonder whether you are just being stupid, and have missed something very obvious that will stop it from working.
For the water storage system, I've been thinking about using pipes, around 15 or 20 cm in diameter, and looking for inspiration and advice on my pan-pipe design, which I think will look a lot nicer than the horizontal pipe rainwater storage system. Either way, I can't find anyone else who has tried it. At least if they have, they haven't blogged, written a book or made a website about it, so it doesn't count.

The closest I can find is the Green Building in Louiseville, Kentucky, which looks to have spiral pipes for rainwater collection.

Then I actually talked to someone about it.

"Wouldn't they be really expensive?" Oli asked. He had laid some pipe before and was shocked by the price he had been charged. I wondered whether that was a supply chain issue, but looking on the internet for white pvc pipes, as thick as possible, the best I could find was 11,130 for 4m lengths of 150mm VU pipe from cut-man.jp. They also had VP, which was a little more expensive. I think the difference is in the wall thickness, 11mm vs 20mm, and there's more information here if you're really interested.

Each 4m length would hold about 70 litres, so the tanks alone would price the system above commercially available ones.

There is a good site recommending low-cost solutions here. But most of them are also low-beauty.

International standards

Wednesday, 17 February 2010

Three months after the first post, things seem to have been very busy, but I'm not sure how fast they have been moving.

We've decided to make a Passive House. This means it must follow strict standards for insulation and airtightness. It will need a mechanical ventilation system that will transfer the heat leaving the building to the heat coming in, so it will maintain ambient temperature.

Whenever I talk about insulation, people seem to automatically say how hot it's going to be in the summer. This seems intuitive but not completely logical. After all, thermos flasks can keep cold things cold, and fridges and freezers are insulated too.

Just like the old joke from the days when David Beckham played for England and Wayne Rooney still had his own hair:
They were stopping for lunch at the England training ground and took out their packed lunches
Rooney: What's that you got there Becks?
Beckham: It's a thermos flask. Posh Spice bought it for me for my birthday
Rooney: Ooh that's good. What's it do?
Beckham: Well, it keeps hot things hot, and cold things cold
Rooney: Sound. What you got in it?
Beckham: Three cups of tea and a choc ice!

There's also a very strong sense in Japan that this country is completely different to the rest of the world, and what happens in Germany cannot be used here. As far as I can tell the same laws of thermodynamics apply, and water and air have more or less the same chemical composition in both places. The climate is certainly a bit different though.

Summer temperature is about five or ten degrees warmer in Matsumoto than in Germany, and five or ten degrees colder in the winter. Also there is a difference between average monthly highs and lows of over ten degrees every month, with August having average highs of 30.5 and lows of 19.8. January swings from 4.9 to -5.5. As well as looking at averages, the extremes are also interesting. In 1987 there were two days when nighttime temperatures stayed above 25 degrees. This was a record. In other words, on pretty much every day of every year, opening the windows at night is going to let in air below 25 degrees.

1943 saw 155 days where the temperature fell below zero. This makes me think that the cold is a more serious problem than the heat!

There are places in Austria with a similar temperature range, for example Eisenstadt or Baden. Searching for "passive house" on the internet in English, you find lots of people making them in the US and talking about making them in the UK. Searching for Passivhaus in Eisenstadt, I found most of the hits were estate agents selling those that have been built over the past twenty years!

Divest from the fossil fuel industry

Pressure is rising from groups calling for investors to stop putting money into the fossil fuel industry. For example, Stanford University is divesting from the coal industry.

People have been saying that it's a bit like the anti-apartheid campaign, when the withdrawal of investments from South African countries brought the regime to its knees, but this may be a problem on a wider scale. Oil is the life blood of our economy and fossil fuel burning is currently our major activity, thermodynamically speaking. It's going to take some bigger, more fundamental changes to get to a world like in Star Trek, even though we already have the mobile phones, tablets and dress codes without ties.

While portfolios free of oil industry stocks are part of the solution, they may not be the whole answer. These companies are incredibly rich and powerful, and momentum will keep them going in the same direction. They are fed growth economics by the economy that they are feeding and making grow. Divesting from them may work, but there may still be enough money out there that will not ask questions beyond the annual income and return on investment.

Also, these companies are run by people who are not complete idiots. They have consciences, and they have children and grand children. They will be very aware that the polar ice is melting, because it's allowing them access to more fossil fuel reserves. Global warming actually means more access to more oil. And they have sharp scientific minds that will be able to join the dots to anthropogenic climate change. They will be well aware that burning the known reserves of fossil fuels will produce far more global warming gases than even the most conservative climate scientists predict is safe.


But as the quote from Upton Sinclair said back in the 1930s: “It is difficult to get a man to understand something, when his salary depends on his not understanding it.”

What the fossil fuel industry needs to do, in the long term interests of the planet, is quite simple:

• Plan a year-on-year reduction in production of fossil fuels.
• Keep a fixed or increasing amount of known fossil fuel reserves in the ground.
• Reduce the amount of fossil fuels sold to people who will burn them.
• Stop wasting money exploring for new fossil fuels. 
• Stop spending money trying to convince people global warming is not happening.

If the companies can adopt these policies, they will become more stable in the long term. Divesting from these companies may be helpful, but another tack is to encourage the shareholders of them to insist they include these policies. Since pension funds often have share portfolios, and share portfolios often have oil shares, this could be a lot of people.

Certainly, if companies in the oil industry change to these policies, they are likely to lose some of their lucrative business, but they will still have plenty of resources to manage. And anyway, there are plenty of companies that have managed to diversify into different businesses.

There was a company in Italy that used to make saddles, but branched into handbags, and is still in business. A stationery shop in Manhattan had been going fifteen years before changing their business to jewellery. And there's a company in Japan that had been making playing cards for around 80 years before it started making video games.

Thanks to http://www.bestoftheleft.com/

Global Warming or Climate Change?

What's in a name?

These terms are often used interchangably. I think there is a difference, and I've tended to use climate change for two reasons. First, politically global warming seems to have taken a lot of flak and climate change seems a little more neutral. Global warming has been attacked and was famously banned from the White House. I imagine using climate change will lead to less knee-jerk reactions and has more chance of getting through to people.

Second, climate change is more scientific.

"Warm" seems to be a bit vague, and often rather nice, while potentially global warming is neither. Also "warm" refers to temperature, and there are all those confusions between temperature and heat.

During reports of record snowfalls on Fox news, the announcer was saying that Al Gore must be feeling really stupid now. Of course, colder weather is a very likely part of a warmer planet when you start looking at the heat of the system, and the way that heat moves around, or stops moving around.

You can even see this on a very small scale if you're in a hot room and have a glass of water with ice in it. The water is pretty much staying the same temperature, but that's because the ice is melting. The ice is also staying the same temperature, since the melting bits of it are no longer ice, but there is less and less of it, and the amount of heat in the system is increasing. When the ice is completely gone, the water temperature will start going up. Interestingly, the level of the water will not go up in this experiment, but if you had Antartica and Greenland in your glass, with the ice on top of them, then you may be in trouble.
The weather reporters know all this, since they were awake in the physics lessons at elementary school, but increasingly weather is getting reported on the news where scientific ignorance is almost a qualification for the job.

It turns out I may be completely wrong about using climate change. A report by the Yale Project on Climate Change Communication suggests that global warming is associated with greater certainty, scientific consensus and understanding that humans are involved, at least on the political left. And everyone, left and right, seems to associate global warming with a greater sense of personal risk.

So I'm adding a tab for Global Warming. This translates into Japanese 地球温暖化 (chi-kyu on-dan-ka, literally Earth-temperature-warm-ification) or usually just 温暖化 (ondanka, warming). They have no need for another term!

Read more from nasa
And Climate Outreach UK

I think I heard this first from On The Media
The picture of the glass and the table (representing Antarctica and Greenland) is from 4-designer.com  

Power conditioner - doing so much more than just inverting

I've been using the terms inverter and power conditioner loosely and interchangeably for the past couple of years, but realise this may be very misguided. I'd assumed those boxes were simply turning the direct current of the panels into the alternating current running through my house and around the local grid.

I should have stayed awake for more of those lectures on power electricity.

Perhaps I did realise there was more going on inside the box, but since our roof is basically evenly exposed to direct sunlight, I've never worried about shading. I know that people recommend shading should be avoided. Recently I heard a story of a solar array that stopped working for a couple of hours a day as the shadow of a telegraph pole crossed it.

Looking at things in terms of current and voltage, and seeing the solar arrays as several solar cells in parallel and in series, it starts to make a bit more sense.

Taking the metaphor of electricity as water, we can roughly equate voltage with how high the water is, and current with how wide the channel is. So a tall, thin waterfall would have a high voltage and low current, while a low, wide waterfall would have a low voltage and high current. The amount of power in each could be the same, and in electrical terms, power is voltage times current.

So we can think of a solar cell a bit like a bucket, on your roof, filling up with drops of sunlight rather than water. And it has a hole in the bottom, so that the water can come out and be used. The power conditioner changes the size of the hole.

Actually, several cells are connected with each other in  parallel to make panels, and the panels are then connected together into columns of six, in our case, then four columns of six are connected in parallel. These then go into the power conditioner.

The relationship between the voltage and current is not straightforward, as you can maybe imagine with a hole in a bucket. If the hole is very big, then all the water is going to go straight out of the bucket, so you have no voltage, but a high current. If there is no hole at all, the voltage will get very high, until it's overflowing, but there will be no current. In electrical terms, these are the closed-circuit current, and open-circuit voltage. As you can imagine if you were fitting a little water wheel to the hole in your bucket, you may want to play around with the size of the hole to get the most power out of it.

The curve for a solar panel is something like this, where the voltage increases with a slight fall of current until the MPP where the current starts dropping very quickly. That's the Maximum Power Point, since the power is the voltage times the current.

The job of the power conditioner is to find that maximum power point, and keep the voltage and current there to get the most out of the panels. The only way it can find it is by experimenting with the load it applies to the system, tuning in to the ideal current. It would be great if it could know just from the voltage and current whether it is at the MPP, but since the curve changes depending on the angle of sunlight, cloud cover, temperature of the panels, dirt, shading and birds flying past, it can't find out without doing another experiment.

The strength of sunlight increases the current, but does not make a huge difference to the voltage.

A number of problems can happen. A solar panel is made up of several cells. If one cell is in shade, the current for that cell will drop. Since the cells are in series, that means the current for the whole panel will drop. To stop this problem, each cell has a bypass wire over the top.

This is what causes the telegraph pole problem, and the basic rule with solar panels is: don't put them in the shade. They should ideally never have any shade. But if they do, at least try to keep it to early mornings and late afternoons.

If some of the cells or panels in a column are shaded, the effect is the same as if all the cells in the panel, or all the panels in the column are shaded. If a bird flies past there could be be a dip in the current. If a bird landed on the roof and stayed there, this would cause problems, but this is unlikely to happen since the panels get really hot.

Which brings us onto the problem of temperature. The open-circuit voltage drops with temperature by around 1% per degree, and the current goes up a tiny bit.

I haven't actually measured the temperature of the panels on our roof, but I know the air underneath them can get up to 80 degrees. Since the air is cooling the panels down, the panels at the top of the roof are going to be slightly hotter than those at the bottom, so they will have different voltage characteristics. This shouldn't be a huge problem, since the optimum current is not going to be very different between panels, and the voltages will add up in series. But I need another post to look further into this question.

For now, the clear messages I've learnt are that shade should be avoided from all panels, and that the panels in an array should all be the same under the sun. And of course, if it's a partially cloudy day, the power conditioner is going to be very busy making constant re-calibrations of the optimum power.

The VI graphs are from mpoweruk.com. They also have a cool table of the efficiency you get from panels at different angles to the horizontal and pointing in different directions, for 35 degrees latitude, which may be useful for anyone living around that neighbourhood, which in fact I do. The only part of the UK near that latitude is Gibraltar.

Starting to feel slightly warm in the White House

Barack Obama arrived on the Normandy beeches last week, a few days after pushing through legislation that could clean up US energy. The White house has so far been slow to realise we are in a green house, but are the Americans going to rush in and save the day, just as they did back in 1944?

There is certainly going to be a fight. The President of the most powerful country in the world has some executive powers, as does the Environmental Protection Agency, formed by unsung hero Richard Nixon. So their plan doesn't have to go through the republican-led democratic chambers, but it may have to get past an army of lawyers. 

This building still as yet unaffected by climate change - must be well insulated. at least from science

The more interesting part of the political environment where this is playing out comes in the curious bedfellows of the right: Christian fundamentalists and oil barons. 

Politics is very difficult to understand, even when it's local, but the way it often works in big parties is that you get fringes that hold the balance of power. With the Republicans, the religious right hold a lot of votes. The oil industry hold a lot of the money.

I should also mention the tobacco industry.

For several years, tobacco was fighting to save it's reputation from allegations that it caused cancer. The strategy of the industry was two-fold. First, support scientific studies that disprove the links between smoking and cancer, also known as junk science. And second, attack the scientific basis that means it is possible to prove something random and probablistic like cancer comes from smoking. 

This same tactic became very useful in the global warming "debate". Money has been spent so effectively debunking the science behind climate change, that some people actually believe climate change itself is a conspiracy. They believe that secret organisations are funding the research to topple the western economies.

Again, there is a strong anti-science element to this. To some extent this comes down to epistemology. In hard sciences, like physics and chemistry, we can usually set up experiments that will pretty much prove or disprove our theories. We can't do this with the climate. There's no way to go back and stop the industrial revolution to see if that would make a cooler planet. We can certainly carry on experimenting by burning fossil fuels, but we don't have a control group, so there is nothing to compare our results against. 

But what does this have to do with religion? Why on earth would the religious right be jumping into bed with oil company executives? Doesn't the bible warn us of the rich and powerful? Isn't there something just un-christian about making money by selling poison to people? And wasn't the eleventh commandment, thou shalt not pollute they neighbour's groundwater supply?

The only possible link I can find is connected with this anti-science. Similar to the science of climate change, biology and geology have some elements that cannot simply be proved by experiments in the lab. For example it's impossible to go back in time, from generation to generation, to see whether evolution really did happen, and whether we have common ancestors among the apes, and going further back still throughout all life on earth.

There has certainly been a backlash against evolution among the religious fundamentalists, and I don't think this is a recent thing. At the Scopes Monkey Trial back in 1925 the State of Tennessee found John Scopes guilty of teaching evolution and fined him $100. In fact it probably goes back to the time of Darwin himself, when religious enclaves across the United States were shielded from the kind of debate that took place in more secular areas, and could see the theory of evolution for what it is: an affront to the very foundation of Christian belief. If only America had been colonised before Galileo, there may still be swathes of North America where people believe the earth revolves around the sun.

So basically this is how it works:

God hates science;

The oil industry hates science (except when they need it to get the oil out of the ground);

So the oil industry loves God (your enemy's enemy is your friend). 

I may, of course, be completely missing the point. 

Also, watch out Barack, what does that say on your badge? In God we trust?

Carpets and air conditioners

Spent Saturday morning cleaning the room for the kids' after-school club. Part of this annual ritual is replacing the carpet. Last year we took the old carpet up to reveal the tatami mats below. I wasn't sure what was going to happen to this carpet, wondering perhaps if it was going to be beaten and then put back on the floor. A new one appeared and the old one was taken away. It turns out this happens every year.

Carpets are not that expensive, but they're certainly not free. Tatami mats are expensive, so it may make financial sense to protect them.

It's difficult to make sense of it in terms of ecological accounting and oil economics. Tatami is a low-carbon agricultural product that is completely recyclable. It is basically woven straw. Traditionally when they are worn out, they are taken out into the fields where they will draw insects away from crops, or they could be left on soil before planting to keep the weeds down.

Anyway, they present a part of a cycle that leaves a light tyre-print on the planet.

Carpets, on the other hand, are usually an amalgamation of materials that are far less friendly. Many are synthetic, with acrylic fibres glued onto a plastic backing. The fibres are all short and not much use for recycling into other textiles, even if they could be separated from the rest of the materials.

"Where are we going to throw this away?" somebody asked. Good question! Probably not into recyclables.

And don't even let me get on to the air conditioner.

Net-zero houses going mainstream

Some news from Proud Green Home about net-zero homes going mainstream. 

I think the key development to make this possible has been the reduction in cost of solar panels. Of course it would be very difficult without all the low-energy building technology, but without a way to generate electricity all bets are off.

The definition of net zero is also a little suspect. If a building is off-grid and not drawing any power from the outside, then it can certainly be said to be net zero. If it is connected to the grid, taking power from the grid and sending power back, then there should be a certain amount of daylight between the generation and the consumption. This is necessary to account for line losses and grid inefficiency.

The electricity that a house draws from the grid is a lot less than the power fed into the grid from thermal or nuclear power stations, because energy is lost in the wires carrying it and in the step-up and step-down transformers that convert the voltage to travel over the long distances we like to keep between out houses and those forms of dirty power. This is called the primary energy factor and varies from country to country. We used the number 2.7 to evaluate our house.

Even if a house uses fossil fuels directly, for example with a gas cooker or oil-fired boiler, you have to take into account the energy used getting the fossil fuels out of the ground, so you can't simply look at the energy use as the amount of energy going in to the house, but you have to add the amount of energy used to get that energy out. This is something like 10% of the energy you get out of them.

Similarly, when we supply our electricity to the grid, a certain amount of it is going to be lost, inadvertently heating up the wires between our house and wherever the electricity is used.

Also we have to address the issue of embodied carbon. In other words, how much energy was used in building the house, and how much carbon did that release? With a net-zero house, the question is: How many years will it take to pay back the carbon released during construction? 

Anyway, there tends to be a trajectory of good ideas from pipe-dream to realm-of-nutters to community-hobby-horse to common practice. Net-zero houses now seem to be breaking through from realm-of-nutters to community-hobby-horse. 

Building a house

(Reposted from September, 2009, with pictures added. )

We're now heading fairly surely towards actually building a house. People keep asking me what kind of house it's going to be, and I'm not really sure how to answer. I wonder if they want me to say that I'm building an igloo, or a fourteenth century Venetian palace or a brick Victorian end terrace. Certainly they want some short answer and not a long description of what colour each wall will be and what the doorknobs will be made of.

It certainly seems like I should have a short answer for this question. As building is much more of a philosophical journey than a technical one I'm just going to set out what I want to do and what that means.

I want to build a house that has an energy consumption of less than zero.

An explanation of why I'd like to build a house that produces energy should not be necessary, and in my opinion in a developed country you should not be allowed to build to consume when you can build to conserve.

Following from this basic condition for building are four topics: Energy efficiency, thermal inertia, generation of electricity and collection of heat. They are of course interconnected, but I'll try to explain each one.

When it's going to be ten below zero outside, a big part of energy efficiency is thermal efficiency. First of all, this depends on the size and shape of the building. The bigger it is, the more heat it will need. The bigger the surface area, the more heat it will lose in the winter, also, the more heat it will gain in the summer when it's over thirty outside. As well as the design and layout of the house and the rooms, the materials used are important. It must be well insulated. A lot of the heat is lost through windows, so these are very important.

Thermal inertia will keep the building at a constant temperature. The more heat the building can contain, the better. This can be both active and passive. The air in rooms contains a certain amount of heat, and it will make a difference how this air moves by convection and how it is forced and fanned where it might not otherwise go, and whether heat can be recuperated from air as it leaves the building. Water, or other liquids, can also store heat and can be moved around the house to where heat is needed. In addition, building materials can store heat. While wood is a good insulator, stone can store a lot more heat. Another possibility is phase change materials: for example floor panels containing a liquid that freezes at 19 degrees. Because of the latent heat of freezing, this can absorb a lot of heat as it is melted, and release a lot of heat as if freezes, all at the ideal temperature of 19 degrees.

Photovoltaic solar cells are pretty much the only practical way of generating electricity in a small plot in the middle of an urban area. The amount of solar energy that falls on the earth in one hour is the same as the amount used by the human race in a year, so some kind of harnessing of this power is very feasible. In fact most kinds of energy production come indirectly from the sun, whether you're burning wood, using fossilised wood in the form of coal or prehistoric microbes in the form of oil, or even using wind and waves that have been generated ultimately by temperature changes and the evaporation of the oceans. Only nuclear power and tidal generation are not originally solar. The sun is, of a course, a large nuclear reactor so I suppose you could say that all energy is ultimately nuclear. Solar cells are not highly efficient, perhaps only converting 10 to 20% of the sun's energy that hit them into electricity, but that's worth a whole new blog.

The collection of heat is most simply achieved by facing windows to the south. As the winter sun is low and the summer sun high, eaves can easily be extended to allow heat in in the winter and keep it out in the summer. This, on its own, is not going to be enough to heat the whole house and of course the more windows there are, the more heat is lost. Solar walls, developed to dry grain in Canadian barns, can absorb heat from the winter sun and convert it to hot air inside the house. Roof mounted solar thermal panels can be used to heat air or water. Combined with photovoltaics these can greatly increase efficiency, also worthy of a whole new blog. Heat pumps are another way of getting heat. They use a small amount of power to defy the second law of thermodynamics and get heat from a colder body.

I'll come onto the colour of the walls and the doorknobs later, but these will probably be influenced by the points above.

original post: http://minuszeroeco.blogspot.jp/2009/09/building-house.html

Lovelock and Reynolds

I was listening to James Lovelock talking the other day and something he said struck a chord. Although he's something like Moses to the ecological pantheon, his own views towards the environment and especially global warming are somewhat ambivalent. He lamented that an ecologist used to be someone who enjoyed walking in the country, but has become an angry protester.

Although the reaction of many to the amount of energy we are using is one of horror, he viewed the whole system in terms of the Reynolds number, and the increase in turbulence with more energy. Reynolds studied non-laminar flow, and you can see the effect of his eponymous number as you turn on a tap, first in a steady trickle, then with ripples and curves as the flow increases, and finally with splashes and crashes as it turns to chaos. In the same way, as we use more energy human output becomes much more interesting, and Lovelock suggested a threshold of one kilowatt per square metre for this to happen.

You probably don't need me to tell you this, but that's the amount of energy that comes from the sun. There are two implications, one dreadful, and the other divine.

The divine implications is that all of the stuff that's happening can be attributed to a concept from physics, and what appears to be chaotic and out of control is just business as usual for the universe. It's tempting to think of the world like a top that has been spinning merrily and steadily for a long time, and is now wobbling erratically before falling over at the end of its turn. Looking at the Reynolds number, rather than about to fall over, we are just starting to taking off.

The dreadful implication is that if we are going to continue to be "interesting" we need to continue using a kilowatt of energy per square metre, and this is not sustainable if we're using primary solar energy in the form of photovoltaics, secondary solar in the form of wind and waves, or historical solar in its various fossil forms.

Humidity makes it hotter ... or colder

When the scientific theory doesn't match your observation of reality, you know you've got one of them wrong. So it's been bothering me for a while that the theory suggests higher humidity makes it feel hotter while the evidence suggests the opposite at colder temperatures.

Finally I've realised the cause of this anomaly.

There are actually two effects of higher humidity on the body losing heat. One reduces the ability of the air to remove heat from the body, and the other increases it.

As we know, the body mainly loses heat through evaporation of the body's perspiration. The ability of this perspiration to evaporate is hindered by high humidity. Humid air just has less carrying capacity for those water droplets and will push up
The other effect is on the air's heat capacity. Water is a very effective carrier of heat, with a kilogramme of the stuff able to hold almost twice as much heat as a kilogramme of air. Adding water to air is going to increase this heat capacity. More heat capacity means a greater ability to take away heat.

Perhaps as it gets hotter, and the difference between body temperature and ambient temperature becomes smaller, the evaporation effect is larger, so humid air makes us feel hotter. Meanwhile, when it gets colder and the difference in temperature is larger, the higher heat capacity effect is larger.

Perhaps, but probably not.

Water certainly does have twice the heat capacity of air, but absolute humidity is measured in grammes of water moisture per kilogramme of air, so the increased heat capacity may only be one percent, comparing dry air with dripping wet air at 10 degrees centigrade. It's difficult to imagine this making the kind of two or three degree differences that humidity makes when it's hot.

Clothes are another matter though. The amount of water they can hold does not depend on temperature and absolute humidity, but on relative humidity and the related vapour pressure. Cotton can hold up to 15% of its weight in water, wool can hold up to 35%. Both of these textiles are hydrophilic and will try to reach an equilibrium with the atmosphere around them steadily releasing or absorbing moisture. That all takes energy, and any water content in the clothes needs to be kept warm.

At last this seems to make sense, although I'm not completely sure it's correct. I know the hiker's adage that cotton kills, but also I've heard that if you are stuck somewhere cold and damp, the best thing you can do is wrap yourself in a woollen blanket, since wool is exothermic.

Notes and references

This article is only tangentially relevant, but has a good explanation of hydrophilic textiles seeking equilibrium with their environment: Iqbal, M., Sohail, M., Ahmed, A., Ahmed, K., Moiz, A. and Ahmed, K. (2012) Textile environmental conditioning: Effect of relative humidity variation on the tensile properties of different fabrics Journal of Analytical Sciences, Methods and Instrumentation 2(2), 92-97

In fact there is much older work on moisture in textiles, for example, Albert C. Walker's Moisture in Textiles (1937, in Bell system technical journal, 16, pp 228-246). This goes into some detail on exactly where the moisture goes within cotton hairs.

And here is some propaganda from New Zealand wool industry: New Zealand Merino Company Limited (no date) Heat and moisture regulation.

You may want to compare this with the moisture content of wood. In textiles terms, of course, wood is just raw rayon.

A Q and A session on physics.stackexchange.com was helpful in debunking my first hypothesis, giving the formula c_s = 1.005 + 1.82H, where 1.005 kJ/kg°C is the heat capacity of dry air, 1.82 kJ/kg°C the heat capacity of water vapour, and H the specific humidity in kg water vapour per kg dry air in the mixture.

The best LED I've ever bought

With its bright light, spidery legs, magnet and sensor, the Ritex Dokodemo portable LED light is probably the best LED I've ever bought. And I've bought quite a few LED lights over the past few years. A lot of them have been completely rubbish. 

I got a battery powered device with three LEDs spaced a few centimetres apart in a row and a magnet on the back that would fit onto the front of the fridge. 

The magnet worked.

Unless you tried to use it to hold something else onto the fridge.

And there was an E17 light that looked pretty promising to replace the incandescent bulb in a table lamp. It had several LEDs in reflective holes that would point light where you wanted it. But it was made of cheap plastic, incapable of conducting the amount of heat away from the LEDs that they would have produced if they'd put out a decent amount of light. 

They did not. Somebody in the design department had not considered that. 

The best lights I'd got so far were bedside lights with single high-power LEDs. Nice heavy bases and plenty of luminous power. 

I saw the Ritex docodemo in a hardware shop and decided it would work well under the stairs. 

Instead of wiring in a light there, from the start the plan was to plug a sensor light into a socket high up on the wall in there. Plug-in sensor lights have been around for a while, and recently they have been LEDs. But they don't put out a lot of light. They are probably OK in a corridor or on stairs so you can see where you're going, but if you're in a store room trying to find something they don't really do their job. 

The Ritex has been keeping it light under the stairs when necessary. It is battery powered and the batteries ran out once, but that was when someone had left it switched on, rather than on sensor mode, since the previous day, and it was starting to dim.

I took it camping with us last weekend, and realised there what a great light it was. 

It was in the area of camping that LEDs made their first big commercial success in delivering light rather than just vaguely letting you know that light was there, as they had been doing since the 1970s when they appeared on electronic panels and then in the seminal digital watch that would come on for a few seconds to show you the time in red. LED head-torches have been around for a while, where their reliability, long life, low power and light weight make any extra cost worth paying. 

We've got a decent collection of LED head torches, but have still been adding unideal candidates to our gallery of camp lights. 

Before it got dark, I lined three of them up along the rope above the table that was going to hold up the tarp covering it. One of the lights gets about seven out of ten on my scale of satisfaction. It's a small puck light with a hook on the back, three AAAs inside and not a bad amount of light, although it seems to take a little while to warm up. It works well hanging from the middle of a tent, and is better than nothing above a table, although it doesn't really give out enough. 

Next to it I put our wind-up LED tilley lamp. This gets about six out of ten. The good point with it is the handle on top so you can charge it when it starts getting dim. It can also be charged from the mains or from a car. The big problem is that it's trying to be a tilley lamp, so instead of sending the light down, where you need it, it sends it around in all directions, which may be useful if you're pretending to be a lighthouse, but is not much use otherwise. And if you were going to be a lighthouse you wouldn't be that bright. 

Next to these I hung the Ritex, and when I turned it on, the other two immediately became parodies of themselves. The puck light is smaller and we'll probably bring it with us, but I think the LED tilley lamp will be staying at home for our next trip. One issue with camping lights is that you don't want things to be too bright when you're camping. Being under the stars is great, but you have to be able to see them. Since this is a sensor light, it will go off if nobody moves for a while, so when you're sitting back you can enjoy the night, but when you need to see what you're doing it will help you out. 

So under the stairs it works perfectly. On the campsite it works perfectly. I haven't had cause to try it out in the event of a power cut, or use it for illumination when I'm working outside at night, but I'm confident it will perform wonderfully in these situations too. 

It's so good, in fact, that I'm going to get another one, or perhaps two. The only problem is that they now offer an updated version, on which you can adjust the colours, and I have to decide whether that's worth the extra 500 yen. I think it probably is. 

Ten tips for building a house

The poster presentation on cool homes for a warming planet gave me the opportunity to revisit and update my ten tips for building a house. It also encouraged me towards concision, so the ten tips are now more pithy.

1. Don't do it.

2. Dedicate a couple of years of your life to this project.

3. Have a vision.

4. Don't trust anyone.

5. Work out who is in charge.

6. Don't let them rush you.

7. Sometimes you have to make decisions and then move on.

8. The ideal home, what you want, what you ask for and what you get are four different things.

9. Assume that everyone thinks you are a complete idiot who knows nothing about house building.

10. When it's all finished, if you get more than about half of what you wanted, you've done really well.


11. It will take longer than you originally thought, and they may try to charge you more than the price you thought you had agreed on.

That's all that went on the poster, but here are some notes just to explain a little more:
1. This is not so much a negative give-up-and-don't-bother, but more because there are loads of houses out there and lots of people already making houses, and you have to wonder: do you really want to add to all of it?
2. The way life works out, there's a good chance that building a house will coincide with having small children and working very hard at your career, both of which may seem, and in fact are, more important.

3. If you don't have a clear idea of what kind of home it will be, the other people building the house may use theirs. If you can find someone with a vision you like, that's great! Beware of marketing slogans masquerading as visions. 

4. Ask questions, search the internet, find out the options, get a second opinion. Be particularly wary of free information, like this.

5. It's probably not you and if you want to be in charge you may have a battle on your hands unless you are really going to build the house yourself. An architect will try to keep himself as your sole contact and prevent you from talking to anyone else on the project. He may then leave everything up to the site foreman or the carpenter, and they may in fact be in charge. Make sure they are on your side!
6. Spend another few days making that decision. Don't worry about changing your mind. You will probably be living in the house and possibly paying back the loan for the rest of your life, and it should be just what you want. It's like shoes: if they don't feel comfortable when you try them on in the shop, then don't buy them. They won't ever feel comfortable on your feet outside, you won't grow into them, and they won't be just right when you've worn them in.
There are two main reasons they want you to make a decision quickly. First, they want to get your project out of the way, and start working on the next one. Second, they have promised one of their friends in the building trade that they are going to be contracting some work, and the timing suits their friends.

7. Sometimes you just have put the decision behind you and start treating it as an unchangeable fact that you will have to live with, and which there is no point in agonising over any more. If buts and ands were pots and pans you'd need to build an extension onto your kitchen.

9. For the most part, they are probably right. The building trade, like many others, seems to work on the principle: a fool and his money are easily separated. People will only be interested in what you think or what you want at the beginning. Very soon they will just ignore you and work on what they think you want.

And you can see even more in the original post published here in June 2012.

Further over-complications for what is, essentially, a big bucket

Or, instead of a leaky syphon, it could just be a very thin syphon.
Going back to first principles, what I want is to divert the rain water from the roof into the garden, and slow it down as much as possible so that it arrives days, or even weeks after falling from the sky. If I can get a syphon working between each water tank, and make it thin enough, it may be able to do this.
The speed of the fluid in a syphon depends only on the difference in height between the top of the water and the bottom of the outlet pipe. According to wikipedia, it's the square root of the height times 2g. So water in a syphon coming out of a 50cm tank will be moving at around 3 metres per second.

Converting that to volume, if you had a pipe of 1cm diameter, it would drain at 14 litres per minute. A hundred-litre tank would be empty in seven minutes. If the pipe was a millimetre in diameter, it would drain at 8 litres per hour and be empty in 12 hours. Five of these tanks in series and the water is going to get from top to bottom in 2 and a half days.

Of course the rainwater is going to have to be really clean with a pipe this thin as it would be really easy to block it. Also this would have to be in addition to a regular overflow since a pipe this thin is not going to be much help in the event of heavy rainfall.

This syphon is essential going to be the same as having a pipe coming out of the bottom of the tank, leading to the tank below. The differences are that a pipe coming out of the bottom of the tank needs a hole in the bottom of the tank, and the syphon will only start working after the tank has overflowed, and will may not start sending water down the system until it has.

Wikipedia also mentions self-priming syphons with a cotton-filled hose that will suck water up by capillary action, then send it down the other side. These are slower than an open hose, which is even better. The system would then start slowly syphon water down as soon as the bottom of the tank is wet.

Of course it may be a good idea to have a hole in the bottom of every tank since it will make them much easier to drain, unless the tanks are going to be fairly small. The drain could lead to a tap into a lower level of tank, and it would be possible to control the trickle down the system.

A rainwater system with syphons and leaks

I've been trying to work out a system of cascading water barrels. Ideally each barrel would contain enough water for one watering. When it emptied it would fill from the next one up, and then when it was full it would empty and water the garden. This would get regular irrigation for the garden. Better still it would only work in the early morning or in the evening, and would not work when it was raining, but those are separate issues.

Right now I just want to think of a system that will run only on gravity and rainwater.

Each water tank needs up to three pipes connecting to it: water in, water out via a tap at the bottom, and an overflow. Generally I want to get water out of the tank at the bottom, so the tanks further up the system don't necessarily need a water-out tap, or if they do it will normally be closed.

The water-in can go on the lid of the tank, which should be straightforward. The overflow needs to go high up on the side, and usually will be dry, so the seal around the hole is not critical. The water-out needs to be near the bottom, and will be wet and under pressure, so the seal is critical. It would be a good thing if I could get out of having to make these. 

If I use a syphon overflow, so a pipe goes into the higher tank high up on the side, and the pipe reaches all the way to the bottom of the higher tank, then feeds into a lower tank so the other end of the pipe is at or below this end, then it will work as a syphon. When the water goes above the overflow hole and the high point of the overflow pipe, the pipe will fill with water, then water will head down the other side of the pipe, and suck water from the bottom of the upper tank. And because it will work as a syphon, it will continue to suck water out either until all the water has gone into the lower tank, or if the lower tank is only a little lower, then it will empty until it reaches an equilibrium and the water will go to the same level in the two tanks. 

Once it's in this situation, adding more water to the top tank will send some water down to the lower tank, so that it will maintain this equilibrium, even if the level of water in the top tank is below the overflow level. 

I was thinking that I could use the same kind of syphon overflow between each tank, from the top to the bottom. However, because the syphons are going to keep tanks in equilibrium after they have filled up, they are going to try to get to the same level, and all the water will syphon itself out. 

So a syphon overflow may work for two tanks that are on more or less the same level, but will not work so well for the whole array. 

Maybe what I need instead is a leaky system. Rather than trying to make leak-free taps coming out of the tanks, perhaps I should be letting water gradually leak down the cascade.

Or perhaps I need to think about leaking air. The syphon won't carry on trying to keep the two tanks level if air is leaking into it. If I can get a little air hole at the top of the syphon tube, when the water goes above that level, the syphon tube will fill with water and start syphoning out. It will carry on syphoning out while there is still water at the top of the syphon tube, but as more and more air gets in, the flow will decrease and then stop. The bigger the air hole, the faster air will leak in and the less the water will syphon out. This could limit the amount of water going to the tank below each time.

Of course another priority is a low-maintenance, self-cleaning system, and the chances are that if the system relied on leaks to work properly, then rather than leaks getting worse as they do when you don't want them, they would fill themselves in. 

Recycle or reduce

In keeping with the ecological theme of this blog, I've decided to start recycling posts. Not the wooden kind.

To help identify these recycled posts, I've added a new tag "old" by which to label them. This seems to me much better than labelling any posts that are new "new". If I do that, they are not going to be new for long, so I'd have to change the label later. Posts that are old when they are posted will always be old.

Probably the recycled posts will have some new comments added. In fact I've been putting this off for a while because I know that by the time I've read through the post, checked the spelling and grammar for the inevitable typos, revised some of my more naive and abrasive comments, mended broken links to any photos in the post, or added images if there were none, it would have taken less time to write a completely new post. So maybe I should be labelling them something like "20% extra new".

Or perhaps rather than recycling posts, I should just be reducing them, and keeping true to the ecological mantra.

Built to last or built to lose

There have been articles about this on treehugger.com and in the Guardian recently, so here is a re-post from August 2011, embellished by a graph from a paper they cite.

It is sometimes hard for me to come to terms with the disposable nature of house building in Japan. Apparently the average life time of a house in Japan is 17 years. In the UK, it would take 1700 years to replace the entire building stock. Although those two numbers are not equivalent, it gives some idea of the difference. I come from a country where houses are built to last. I grew up in a house that was a couple of hundred years old, which was not particularly unusual. The house we rent here now is about a hundred years old, and it's a constant surprise that it is still here.

(This shows the value of buildings dropping to zero after 15 years, from this paper by Richard Koo and Masaya Sasaki.)

It is easy to write this off as bad workmanship or see it in terms of a nation that loves new things and is obsessed with the disposal of the old. It has been suggested that Japan must have a large construction industry as there are periodic needs for mass rebuilding after natural disasters. It seems that the construction industry is a powerful lobby and they can veto any suggestions to improve building standards. There is also, no doubt, something left over from the post-war rebuilding of Japan where fast, cheap building was the only option. I think there is no simple reason.

But there is a vicious circle, as I found when I was asking the bank about loans. As far as they are concerned, and as far as the taxman is concerned too, a house is worth nothing after twenty-five years. The biggest drop in value is the moment you move in. In most cases, the house is worth less than you paid for it as soon as you turn the key and walk over the threshold.

The people at the bank weren't particularly interested in the building specs when they were valuing the property, instead they look at the houses in the neighbourhood and take an average per floor area. In fact as far as collateral, they don't really take the house into consideration but just look at the value of the land. So unless you're building with cash, and have lots of it, you're at the mercy of a bank that is going to encourage you to reduce the spec. There is little incentive to build something that will last more than 25 years, although one glimmer of hope is a recent standard for a hundred-year house that can open the door to lower mortgage rates.

Houses in the UK, and probably the rest of Europe, the US and Australia, steadily increase in value. From when they are built, they start to get more valuable. After a while, when they hit an unfashionable or unserviceable age they stop getting more valuable, but even then they will hold their value. A little later they start to go up again. There are certainly stories of people with negative equity and people who lose out, but that's usually short term and a combination of local conditions and some measure of extra bad luck for the house owners, forcing them to buy and sell at the wrong times.

As we were looking around Matsumoto for houses and land, we often saw old houses for sale that were very reasonable. If they weren't sold after a year or two, they were knocked down, and the price of the land, without a house, would go up. There is a common wisdom here that renovating old houses is more expensive than building new ones, and I think it may be true if you're comparing a low-cost new-build with restoring a ruin to its ancient form. I think it's more likely to be propaganda by the building trade, a symptom of few people or businesses that renovate, and the prevailing trend of not looking after houses, but letting them wear out until they are knocked down, which is all part of the vicious cycle.

Having said that, if I look at the house we are in now and if we were to bring it up to a comfortable level to live in, we'd have to replace the roof, replace the windows that make up the north and south walls, and pull up the floors and do some work on what's underneath. By the time we'd taken all the bits off that need changing, we'd be left with a wooden frame, and that probably would have to be made earthquake proof as their are no diagonal supports and the whole thing is a mechanism. Also, I'd want to raise all the horizontal beams so the doorways are at least twenty or thirty centimetres above my head rather than two or three centimetres below, just where there is a permanent bruise on my forehead.

One way of looking at this difference is in terms of agriculture. The UK traditionally has pastoral farming, so buildings have been essential to provide shelter for people and animals, so that animals can feed off the surrounding land. Buildings have intrinsic value in this sense. Japanese agriculture is arable, so that land itself is valuable for intensive planting of crops. Any building is going to reduce this value by stopping the production of crops.

Another consequence is in the notion of "home". For the British, a home is a solid thing. An Englishman's home is his castle. For Japanese people, any building seems arbitrary and the sense of belonging is to a community of people.

So while I see what I am doing as an investment, and put myself on a mission to make a small change to the way houses are built and treated here, I'm probably just pouring cash into a hole in the ground, and the main interest of most of the people involved is to catch some of that cash as it falls. I'm sure the house could be built to a similar specification for less cost, and hopefully everyone involved will learn something on the way, so if another idiot comes along asking for a house that doesn't consume, it'll be easier for everyone concerned.

Original post: Built to last or built to lose
Thank you PJ for sending the treehugger article.

Rain water tanks - buy or build

An early decision as I plant the seeds that will eventually lead to a rain water harvest is whether to buy or build. Either way needs careful consideration of design features of the system.

Panasonic do a few rainwater tanks. They have a 150 litre tank for 55,000 yen, and a 200 litre tank for 70,000 yen. They also have a 340 litre wall tank for 65,000 yen. It actually looks like a wall, although I don't think any walls actually look like this. You'd have to get your house sidings redone to match it! Not sure if this was a translation error.

They are not the most expensive, but certainly not the cheapest. Maruichi have a 140 litre tank for 29,000 yen

There's a whole range of tanks here from Direct Tank, with and without lids. They look very simple, with a basic design, no frills, no included connecting parts. And expensive! For example a 300 litre tank with a lid for 52,000 yen.

Then there is Takiron, with a 120 litre tank for 29,700 yen. They also have a 150 litre wall type for 41,000 yen. You can pay more for something that is less attractive!

The best looking tanks may be either the German Groban Slimline 300 litre at 44,000 yen. Except that it's beige. Only 99 euros on ebay, so somebody is making a profit. It's got the ridges around the edge, which I'm not completely convinced about aesthetically, but I guess they have a pretty good functional rationale. 

Or the Aquatower, 150-200 litres depending where you put the tap for 39,700 yen. Or 100 litres depending which website you look at. They have a very clever looking drainpipe fitting which will stop dirty drizzle from getting into the tank, and also act as an overflow if it is aligned with the top of the tank. 

The best I can get is something like 150 yen per litre of storage. This is very close to the price I pay for each cubic metre. A cubic metre is 1,000 litres, so I would need to fill and empty the tank 1,000 times for it to pay off in purely financial terms. If I tried really hard I could probably fill and empty the tank 20 times in a year, so it would take 50 years to cover the initial cost

Of course everything is not purely financial. If I'd been interested in making money, I would probably have invested in shares of the oil industry or a nuclear power station rather than putting solar panels on my roof. Using the water off the roof will not only have benefits in reducing the demand for local water, and providing my garden with cleaner water than the tap does, it will provide a store of relatively clean water in the case of some natural disaster that destroys the municipal water supply. At least it would if such a disaster did not destroy my water system too. Anyway, I can probably build a system for much less than this cost, provided I spend several hours thinking about it, and not putting any financial value to that time. 

Things to avoid in a water storage system

There are a few things to watch out for in designing a rain water collection system. These probably include mosquitos, algae, freezing, over flow, first flush, noise, leaks and condensation.
watercache.com gives some great information on first flush devices, and there's more here.

The basic issue here is that between rainfall your roof can accumulate a lot of crap. Some literal, of the avian variety, some more in the engineering sense of the word. So when it does rain the first few millimetres will be dirty. This is likely to be a bigger problem when there are longer dry periods, and is probably affected by local pollution.

Research in Tokyo found the first 1-1.5 cm from the roof is dirty, and it seems a rule of thumb is that you should throw away the first 40 litres per 100 square metres of roof. There is no definitive amount of rain needed to clean the roof, and it has been pointed out that rain often starts as a trickle so if the first-flush strategy is to divert a fixed volume of rain at the beginning of a rainfall, then this may all be drizzle, and when the heavy rain comes and stats washing the roof it will go straight into the tank.

The important point is that keeping the water going into the tank as clean as possible will keep maintenance and cleaning easier and make the system last longer. Filters obviously come into this too, and I should probably have put that in the list.

Also obviously, there must be a strategy for the tank overflowing. Since this is likely to happen when it's raining heavily, the overflow pipe should be as big as the pipes going in, and possibly bigger since the pipes going in could be full of water, but the overflow pipe, at least at the beginning, will be full of air.

Even if the tank doesn't leak, there may be a fair bit of condensation on it in the summer, and there is likely to be a pool of water at the bottom, so getting a well drained area below the tank is a good idea.

There's a good site here from the Australian government and lots of information just in this thread on the Alternative Technology Association. They cover most points.

I'm not sure about noise but if there is a lot of water moving around, it's possible that it could be be dripping, hissing or humming. It's probably going to do most moving while it's raining so this is unlikely to be a serious problem.

Freezing is likely to be a challenge when the average temparature is below zero for at least a couple of weeks of the year, so either the system needs to be drained, insulated or set up so the water can freeze without breaking anything.