YKK zipping up the market, or closing windows on it?

Here's a breakdown of the kinds of windows used in different countries. The striking thing is the high proportion of aluminium windows used in Japan.  You may remember that aluminium has a thermal conductivity around a thousand times bigger than wood or PVC. In fact it would be difficult to find a material for window frames which would conduct more heat, and each time I see them, I shake my head in disbelief. As you can see from the chart, living in Japan I do a lot of head-shaking.

For those reading in black and white, the charts are for (West to East) France, UK, Germany, Scandinavia, Korea, Japan, US. (No mention of India, China or Russia.) As for the colours, pink is aluminium, Yellow is wood, light blue is compound (for example aluminium with insulation), turquoise is PVC, which the site is promoting, showing in the table how Germany, the US and trendy neighbour South Korea use PVC in 60, 67 and a whopping 80% of their windows, while poor Japan only uses 7%. The red circle proclaims PVC is the global standard.
Looking more closely, for the Japan pie chart, yellow is marked aluminum compound, and wooden windows appear to be as unusual here as aluminium is in Scandinavia. And you thought wood was a traditional building material in Japan! I just checked the source data, where wooden windows make up less than 0.1%, so the data may in fact be completely ignoring wooden windows.
So why is this happening? Not so much the lack of wood or scarcity of PVC, but why so many aluminium windows?
Just a hypothesis, but what if the Japanese window manufacturing industry were controlled by the aluminium industry? The number one objective of the Japanese aluminium industry is to increase the use of aluminium. This is not surprising, and may not be sinister, unless you consider the prevalence of growth economics as an evil threat to our survival on the planet, which I for one do.
Protecting the environment is also an objective of the Japan Aluminium Association, so there may be a conflict of interest. For example, using aluminium in window frames will increase the use of aluminium. Using PVC or wood will reduce heating costs and be good for the environment. Increasing the use of aluminium is higher on the list of priorities, so we'd better do that!
If this hypothesis were true we would see the largest window manufacturers in Japan belonging to the Aluminium industry.
They may be better known around the world for the other part of their business, zips and zippers, where they have a massive global market share, but YKK also have a substantial architectural parts business, and make most of the window frames in Japan. YKK do belong to the Japan Aluminium Association.
However, if you look for YKK windows in English, you'll find information like this on their US plant, making and supplying vinyl windows. Not a mention of aluminium. Their Japanese website talks about the new windows they are making, with insulated aluminium frames. They don't seem to mention PVC frames for the domestic market. The mission statement and their fancy environment report talk about sustainability and energy efficiency, but when it comes to details, there's more emphasis on double glazing and low-e glass, but the care still aluminium. So more thermal bridges leading to condensation and while the aluminium frames aren't going to rot or rust, the wooden frames of the building they are fitted into may. Rather than replacing the windows, people will need to replace the building! So there is a different story for the English-speaking market, where "PVC is the standard" and domestic Japan, where there may still be some people who think that aluminium is a wonderful new product, and it's certainly seen as a normal way of fitting bits of glass into the walls of your wooden house.
Looking through the main shareholders of YKK, which is not listed on the stock exchange, there is no obvious link between YKK and the rest of the aluminium industry, and perhaps aluminium frames are just used because they are cheaper, and considered a normal part of a Japanese house. Momentum keeps the world turning. In some cases it keeps us hurling towards the abyss.
Or perhaps it is the power and inertia of YKK's president, Tadahiro Yoshida, son of the founder, who turned around the window business that was inherited from his uncle, and perhaps has the same view of windows as he did when he started managing the company in the 1970s.
The invention of the Sony Walkman is one example of how the strong ideas of a company leader can steer the company, but here is another about YKK, that I read on Forbes.com. I don't usually read Forbes magazine but it came up in one of my searches. Tadao Yoshida, founder and father, once announced that "golf will ruin Japan". He probably just meant that too much focus on playing golf would mean companies wasting money and Japan possibly taking its eye off the ball of business, but this lead to golf fans within the company keeping their habits a secret, until after Tadahiro, the son, had taken over and he announced one day that he was off to play golf. At this point the golfers could reveal their habit once again and many came out of the closet.
So who knows why aluminium is so prominent in Japanese windows, but the only way to change it is to raise awareness among consumers, and more importantly architects and builders, that there is an option.
Note: It was difficult to find precise information on the Japanese window industry. Although YKK seems to be the biggest producer, they do not mention "market share" once in their annual report. I kept getting google hits for a report on the global window and door market, but they were charging for it. It would be nice if information on windows were more transparent. 
Acknowledgement: The world window map is from Excel Shanon who seem to be making the best windows in Japan at the moment, although I think they are still somewhat limited by the thickness of glass that will fit in the standard frame size, so their triple glazed windows may not perform much worse if the middle glass layer were removed and they become double glazed.

YKK

Excel Shanon

Pazen

Mind the gap - A short history of double glazing

Commercially available double-glazed windows were first available in the US as Thermopane, patented by C. D. Haven in the 1930s, although he does not claim to have invented them, and mentions several previous patents, some of which had expired. Apparently the idea came from Victorian Scots, but double glazing did not take off in the UK until much later. In parts of the US through the prosperous 1950s Thermopane windows were the height of luxury. Meanwhile in the UK, double glazed windows were expensive and houses were heated with coal that was simply coming out of the ground, so the financial incentive was not there.

Double glazing hit Europe in the 1970s in the wake of the oil shock. The response to high oil prices was an attempt to increase energy efficiency of buildings. The same energy shock spurred the Japanese to make more efficient electrical goods. The main effects on US policy seem to have been a 55 mile per hour speed limit, and increased interest in Middle Eastern politics, although it undeniably increased awareness of environmental issues and possibilities for saving energy.

The first double glazing in the UK had a quarter-inch, 6 mm air gap. The extra air made a huge difference to the insulation, and people's heating bills, and double glazing salesmen trod the nation's doorsteps and appeared on off-peak TV advertising, no doubt late on those cold evenings of autumn and winter.

The double glazing sales teams were competing against each other, and sooner or later someone brought out panes with an 8 mm air gap. A bigger gap meant more insulation, but more importantly, a bigger number for salesmen to impress their marks with. They could also, perhaps, go back to old customers, and persuade them to upgrade to these new, improved models.  Next came a 12 mm gap, and half an inch became the standard. The insulation was significantly better, although the improvements were not as stark as the jump from single to double panes.

Science and engineering can reach optimum values, but sales and advertising always want more, and the windows continued to get thicker. Unfortunately, beyond 12 mm the increased insulation of the extra air has less and less effect because the air within the enclosure starts to circulate, air heating up on the inside pane, flowing up to the top as hot air rises, then losing that heat to the outside pane as it heads down the other side. 

So they could try bringing out windows with a bigger gap, sounding better, but they wouldn't perform any better.

According to  the window man, the introduction of argon filling was just a way to get thicker windows that could both sound better, and perform better. There is another story though.

Humidity pump

Another way of looking at humidity is in the pressure of the water vapour suspended in the air. In a wall, there is a temperature gradient between the inside temperature and the outside temperature. In the steady state this is going to be a straight line. If the insulation is glass fibre, air and moisture can pass with some freedom. If hot air from inside is passing all the way outside, as the temperature drops the humidity will rise so at some point the humidity will likely reach 100% and you will get condensation. To stop this, you need vapour barriers that will stop the air inside the house flowing through the wall structure. Then, the air will stop flowing, and in theory at least, you'll get constant humidity throughout the wall, even though the temperature is dropping and there is much less absolute moisture content in the air close to the outside than there is close to the inside.

In the summer, the temperature outside is higher, so you have the opposite situation and the danger of water condensing on the way in, as the temperature drops. The humidity inside the house is higher, so the walls may get too humid at some point.

Wufi software simulates the performance of a wall structure over time, and you can see an example below, although this is not for our house!

Just like insulation slowing down the heat rather than stopping it from escaping, vapour barriers and other kinds of waterproofing do not stop water, they just slow it down. Anyone who has stayed in the rain for long enough in waterproof clothes knows this. It's fine for a while, but eventually the rain will get through. I remember my Dad discovering how waterproof his boots were after a very rainy walk around Haweswater in the English Lake District--water had got into them but it took for ever to get out again. Cheap waterproofs can also be sweat proof, so sooner or later you're going to be wet inside anyway.

Essentially our house has a couple of rain coats on. On the outside is Tyvek sheet is made by Dupont, who also make Goretex rainwear, which is designed to stop precipitation from getting in while allowing perspiration to get out. We need the same thing in a house, so that moisture does not build up within the wall structure, leading to rot. Tyvek stops drops of water from getting through, but will let water vapour pass, so the walls can stay dry.

We used Intello inside the wall structure, which allows very little moisture through in the winter, preventing condensation and rotting walls. In the summer, it opens up and lets moisture through, which allows the walls to dry out.

You can see an interesting effect below of humidity going up with temperature, instead of going down as it usually does. The first chart is the normal situation, where the relative humidity gets lower as the temperature goes up, since the absolute humidity is the same, but the air's capacity for water vapour increases. The lines at the top are humidity, the higher one outside the house, and the lower inside the house. The temperature lines are below.

The next chart shows the humidity and temperature within the wall, when the sun is beating down outside, making the temperature just inside the Tyvek high. This makes the humidity low, and as a result, humidity starts flowing outwards through the wall. We're measuring temperature and humidity in the middle of the wall, so at some point it should be possible to test how the wall performs in real conditions.　After almost two years, the humidity seems to be staying in a safe range.

The Scottish problem

In the process of preparing a presentation about plus-energy housing, I noticed just how many Scots were involved in the whole business of thermodynamics. It's probably no exaggeration to say that James Watt invented global warming when he came up with the idea of burning coal to pump water out of mines so that you could get more coal out. The irony is that making a house more energy-efficient needs the same level of understanding of science that started the problems in the first place. Oh brave new world that has such people in it. 

James Clerk Maxwell was another Scot, discovering the demon better known as the second law of thermodynamics. This is the gambler's ruin theory of heat. And I didn't even get onto James Dewar, who invented the Thermos flask but unfortunately did not file a patent for it. 

It has been alleged that double glazing was invented in Scotland in Victorian times, although it was not commercialised until the 1930s in the US. The inventor of that was probably called James too. In fact another person involved with the whole business was James Joule, but he was a brewer from Manchester. Then there was Lord Kelvin who was not called James and may not have been born in Scotland, but did his work there. 

And he's not usually considered a scientist, but Billy Connolly's line about there being no such thing as bad weather, just the wrong clothes, belies a deep understanding of heat that would serve the building industry well: there's no such thing as a harsh climate, just inappropriate housing.

So given that global warming was all originally the fault of Scots, and since people in the United States are gradually starting to believe in it, it's only a matter of time before the lawyers get hold of the idea and they decide to sue. It therefore seems like a good idea for the English to support devolution. 

And I don't say that because I'm not British deep down. It's true that I usually tell people I'm English but that's more a matter of convenience since people where I live have usually heard of England, and use a similar name in their language, and it takes several minutes to explain that the country is not really England but the United Kingdom. It takes longer still to convince them that the first international football match was between England and Scotland, and that it was indeed an international match. At least they do appreciate the explanation of the Union Jack, until they start asking where the flag for Wales is. 

The point is, when those lawyers in Manhattan start suing Scotland, if it's a separate country from England, then at least some people in Britain will be unaffected. Of course this may come back to bite those south of the border since many of the insurance companies are in London. 

 

A random assortment of websites relating to solar power

Here are some links to sites about solar power with varying levels of relevance to each other and the real world. Actually a lot of the links are not even about solar power but at some point they seemed worth keeping, so it's just possible somebody else may find them useful. They are all working at the time of posting, although I had to throw a few out of the longer list I had before.

There's a slim chance that somebody who reads this may find one of these sites interesting, and I'm not sure whether to press the send button, or delete.

This is Chofu's Solar heater (in Japanese) http://www.chofu.co.jp/

Here are some water tanks (also in Japanese) http://www.fujitaka.com/

This is about heating in Passive Houses. http://www.passivhaustagung.de/Passive_House_E/

Not really connected to solar power, but here's a company in India supplying phase change materials: http://www.pcmenergy.com/

Here's a paper about using solar water heating with phase change materials, actually making the last link relevant. Anant Shuklaa, D. Buddhib, R. L. Sawhneya, (2009). Renewable and Sustainable Energy Reviews, 13(8), 2119–2125. linkinghub.elsevier.com

And another one from Atul Sharmaa, V. V. Tyagib, C. R. Chena, D. Buddhib, (2009). Renewable and Sustainable Energy Reviews, 13(2), 318–345 http://www.sciencedirect.com/science

The ideal solar thermal system

We ended up not choosing solar thermal, and just using photovoltaics which have no moving parts and nothing running through them that can freeze or boil. Below are some ideas from the planning phase of our building based on theory and various research.

The ideal solar thermal system stores heat in a single hot water tank which can collect heat from solar panels, add heat from a backup boiler or heater, provide hot water, and distribute heat to the radiators, underfloor heating or the ventilation system.

The problems and challenges facing solar thermal systems include overheating, chattering, hygiene and freezing. People often worry about not getting enough heat from their solar heaters, but apparently overheating is the biggest cause of failure for solar systems, and one reason why systems in Japan are usually under-sized, meeting demand only at maxiumum output. Overheating causes steam and high pressures, which can shorten the lifetime of elements within the system. It should be possible to design a system that can withstand a range of pressures and temperatures. After all, steam heating systems have been around for over a hundred years. Evidently they are not always designed for the pressures and temperatures that sooner or later they well reach, and solar systems often fail within five years.

Another problem is chattering. This happens when the hot water from the solar system is fluctuating around the level at which extra heat must be added. As with photovoltaics, sunny days are are no problem, as there is a large and constant amount of heat. Overcast or rainy days are not a problem, because there is a small and constant amount of heat. Partially cloudy days are a problem. Because solar systems cannot guarantee to supply enough heat all the time, there must be a backup system. If the solar heating is sufficient, the backup heater is not needed; if the solar heat is insufficient, for example on a snowy day, the backup must switch on. In certain weather conditions, the backup system may be switching on and off several times, rapidly wearing out motors and switches. A certain level of sophistication is needed in the control system. This problem should not be insurmountable, for example the backup system could only switch on after the sun has gone down.

Another issue is storage of water within the tank. The tank could most efficiently contain the same fluid used for the panels and for the domestic hot water. This is most efficient, however there may be issues with legionnaires disease, which thrives in the kind of temperatures that you will often get in a solar water system. In addition, tap water is liable to freeze, so any water left in the panels at night time could lead to problems, since freezing water expands and tends to burst pipes. Using a refrigerant within the solar circuit, and a heat exchanger for the domestic hot water also has advantages, for example in allowing higher pressure within the panels. Because of the heat exchanger it is, of course, less efficient.

One choice with solar systems is whether to use a drainback or continuous system. In the continuous system a refrigerant is used, and as soon as the water in the panels heats up, flow starts, transferring the heat from the panels outside into the tank inside. In the drainback system, water is sent to fill the panels in the morning, or at least when the panels start heating up. It is then returned either when the water has reached a certain temperature, or at the end of the day when it's got all the radiation it can get, before it starts cooling down. The advantages with this system are that overheating is avoided, since the hot water is sent into the house before it overheats. Tap water can be used, since there is no danger of the panels freezing as water will not be sent there if it is too cold, and will be sent into the house before the temperature drops.

Another issue is the performance of the hot water supply system. Ideally there should be time and volume settings so that the bath be filled to the desired volume and temperature. There should ideally be a means for re-heating the water within the tub, so that water may be saved as is customary in Japanese houses. Most commercially available hot water systems in Japan have all these functions ready fitted, although the controllers cannot necessarily be acquired separately. Designing your own system would be a challenge.

From the beginning solar thermal seemed very attractive as a way of reducing energy. Solar thermal panels turn over half the sun's energy into heat, and are three or four times more efficient that photovoltaics. In the end a major considerations for not choosing solar thermal were to keep the systems simple and the roof elegant. Thermally it may have made sense, but financially, in terms of initial cost and the relative costs of purchased and re-sold electricity, photovoltaics were the obvious choice. And if the solar thermal system was going to fail within five years, even the superior thermal efficiency of the system becomes doubtful. Another factor was our NEDO grant application, which I'll write more on later.