Thursday, 11 October 2018

How to Solve Problems

Teaching is a constant learning process. At least it should be. One problem with being a teacher is that you often get into situations where you think you're right, which can make it difficult for you to change what you're doing. In the classical model of the teacher, you can be expected to be right in your knowledge, otherwise you wouldn't be there. But when it comes to how to share that knowledge, or in what order to present it, there is less clear right and wrong and just a whole range of choices.

I believe in the power of problem solving for teaching. This translates to a belief in the power of learners to solve problems, and for them to learn something in the process. The problem is, not all learners are good at solving problems, and many have been through educational systems where they have not been expected to solve them. At least not the kind of problems that I give them. 

So how do I solve this problem?


Given that I want to teach problem solving skills, I probably just have to be a lot more open and transparent about it. I have been mentioning a few things to the students in passing: like suggesting they draw diagrams to help them work out problems, or advising them to write their calculations out carefully and clearly on lots of paper so it's easy to go back later and see what they did. I need to be much more explicit about the steps of the problem solving process, and give them a bit more practice in each step rather than just throwing a problem at them and hoping they'll work it all out. Too often the problem I've been throwing at them is how to solve problems, which is way too abstract.

Here are some steps:
  • Formulate the problem
The first step is to work out exactly what the problem is. Draw a picture. Write down what you know. Draw another picture. Put question marks where you need to find an answer. 
  • Find solutions
Now that you know the problem, you can think about solutions. What strategies are available? Are there different ways to solve the problem. Make a list!
  • Choose a solution
Which is the best way to solve the problem? What are the steps? 
  • Prepare tools
If you are calculating, your main tools are equations. If you are using a computer, the tool is the software. You also needs data. There will be physical properties that need to be looked up from tables, some things may need to be measured. Some will need to be estimated.
  • Calculate
Use lots of paper. Avoid any shortcuts that will not be obvious to someone looking at the calculations later. If you miss out steps on paper, there's a higher chance you'll make a mistake.
  • Check the calculation
Ideally get someone else to check your calculation. It's often difficult to see your own mistakes.
  • Check the answer
Eyeball it. Compare it with your real world experience. So you calculated that this pencil weighs a million tonnes? Maybe you should think again.
  • Check the error
Answers in the real world are never perfect. Their accuracy depends on the accuracy of the numbers going in, and the accuracy of any equations you used. Know how wrong you are!

That's eight steps, and no fancy acronym to go with them. I can start building them into my lessons and watch what happens.

It's probably also worth talking about engineering problems and how they are different to the problems that come up in education. They have often been conditioned to find one correct answer, but over in the real world there is usually more than one answer, and more than one way of finding the answer. Good engineering will find the best solution to a problem, given a range of criteria. The most important considerations are often cost, safety and performance, and the best solution may be optimised between them. Cost itself can be in materials, equipment and construction processes. 

Of course one factor in this optimisation is the length of time the engineer spends on the problem itself, since engineers are a scarce resource and their time precious.

So I think I've written enough on this topic for now.

[Image taken from https://schooltutoring.com. not sure where they got it from!]

Wednesday, 3 October 2018

Low Energy Building First Class Fact Checking

The first lesson has some background on the energy problem. I have the carbon graph, showing the emissions taking off around 1800, driven by a smooth exponential growth in coal production. Actually the coal was not really being produced—that happened back in the carboniferous period 300 million years ago—it was being moved around and then burnt. The graph shows oil starting, then gas a little later, each in its own exponential variant. Meanwhile, the emissions from coal have still been increasing. 

I've been saying "until this year" with a quizzical optimism, and finally it looks like "production" of coal is down, which is a sign that we will eventually burn less of it. 


This graph from BP is still pretty scary.  That gray coal line definitely seems to be getting thicker. Also alarming is the sandy bit at the bottom, which is biomass. Before coal that was the only source of heat, and it was more or less constant until the middle of the twentieth century. Now that is on the rise. I'm not sure how much is in industrial use of biomass, for example replacing coal in thermal power stations, and how much is domestic use from fuel-poor burning what they can find. 

If you look carefully you can see the thin yellow strip of renewables at the top, like a sprinkling of snow on a mountain top. While this has increased from its previous levels of invisible and insignificant, it is still a long way off replacing any of the behemoths beneath it.

It should be noted that while BP's data can probably be trusted, their main business is still in selling fossil fuels, and their business model is still based on selling more. The graph goes up to 2013. 

The next graph is from the International Energy Agency, and gives us hope that 2013 was around the high point of coal, with production in China and the OECD decreasing. It's tempting to see that as a peak, and look forward to a steady then rapid decline in coal extraction.

However, Dick Van Dyke nostalgia has been strong in the US, and production was up last year. So, once again, it's too early to tell.

I guess it depends on who wins between the people selling fossil fuels, and people promoting energy efficiency and renewable energy. 

While checking figures, I also revised the proportion of Japanese energy that is imported from 80% up to 90%. The lower figure was pre-Fukushima, which had got into my slides at the beginning, and I've now corrected several years late. (Japan was 20.2% energy self-sufficient in 2010, and 8.3% self sufficiency in 2016 according to METI.)

I had been telling student that Japanese houses use 30% of the country's total energy, while in fact its more accurate to say that buildings in Japan use around 30% of the total energy. 

Whichever way you look at it, the amount of energy imported can be reduced if we get serious about low energy buildings.

I also found some interesting changes in energy use, which I may need to mention some time, although should probably work out more carefully first. 

Between 1973 and 2015, residential energy use in Japan increased by 90%, office energy use increase by 140% and industrial energy reduced by 20%. 

I'm not sure to what extent this is a sign that houses and offices have become much less efficient, while industry has become more efficient, or whether it shows that Japanese industry is producing less, and people are spending more time in offices and more money on energy-consuming appliances in their houses. 


(Dick Van Dyke from trailer screenshot - Mary Poppins Trailer, Public Domain, https://commons.wikimedia.org/w/index.php?curid=34700974)


Wednesday, 26 September 2018

Low Energy Building Course: Every Tuesday Afternoon—Starts 2nd October

Not only can students at my university take the 15-week Low Energy Building course, it's also open to members of the public!

You can read the syllabus below. And find more information about other courses open to the public here.

See you in room 26 half past two!

(1)授業のねらい【授業の達成目標】
・Students will learn how basic science affects buildings
・Students will learn how buildings affect the environment and how culture affects building practices
【授業のねらい】
Buildings use over one third of all energy consumed in Japan, as in many other developed countries. In a world of increasing population and limited fossil fuel reserves, reduction in building energy consumption is important. As well as drastically reducing consumption, low energy buildings can be more comfortable, more healthy and less expensive over their lifetime.
This course will introduce students to the principles, the practicalities, and the future of low-energy building.
他の先進国と同様、日本で消費されているエネルギーの3割は、住宅で使われています。人口が増加し、化石燃料が限られてくる世界では、省エネルギー住宅が必要となります。エネルギー消費を減らすことで、居住者に快適で健康的な暮らしをもたらし、建物の耐用年数においても経済的です。本講義では、省エネ住宅の仕組み、その実用性と将来について紹介します。
(2)授業の概要This course will show how simple scientific principles affect buildings, and how insulation, airtightness and good windows can lead to houses with very low energy consumption. We will see how the use of solar power can make buildings that produce energy. We will look at low-energy buildings around the world, including the German Passivhaus standard. We will also consider the design process, including compromise, optimisation and guesstimates.
(3)授業のキーワード環境、物理学、建築、省エネ、熱力学、太陽光発電
(4)授業計画1. What is a low-energy building?
2. What is energy?
3. Insulation and thermal envelopes
4. Compound insulation and thermal bridges
5. Why do we feel hot or cold?
6. Air and water
7. Windows
8. Ventilation
9. Windows 2.0
10. Energy standards and low-energy building around the world
11. To zero energy and beyond: Buildings as solar generators
12. Passivhaus
13. Economics and ecology, embodied carbon and life cycle analysis
14. Presentations
15. Review

This plan may change to meet the needs of the class
(5)成績評価の方法Students must complete weekly online activities in eALPs to pass this course. Students will be expected to participate in class and give presentations.
Online quizzes: 80%
Online forums:  10%
Presentations: 10%
(6)成績評価の基準The university policy states that students need 60% to pass, 70% for a B, 80% for an A, and 90% for an S.
(7)事前事後学習の内容Additional information will be made available on eALPS.
(8)履修上の注意The class will mainly be conducted in English. It will be possible for students to ask questions, complete assignments and give presentations in Japanese.
本講座は主に英語で行いますが、受講生からの質問、課題の提出、発表は日本語でも結構です。

Thursday, 26 April 2018

The 2018 blog post hiatus

​There has been some speculation that the recent lack of blog posts is evidence that low energy building is not happening. ​I'd like to take this opportunity to state that this is simply not true.

W​e do not yet know all the reasons for this hiatus in blog posts, but low energy buildings is certainly continuing. Also there is no doubt that low energy buildings are man-made.

It would be unwise to make any predictions about the exact return and future frequency of blog posts.

In the meantime, you can make full use of the labels or search function. If you're thinking of building your own house, you may want to start here:


Monday, 19 March 2018

House of the Year in Energy Awards 2017

​Congratulations to IS Design, of Nagano City, ​winners of the Grand Prize of the House of the Year in Energy Awards 2017. Perhaps the smallest company ever to win a grand prize. More about IS in another post, but from the buildings I've seen, they deserve the prize.

​ Another ​three builders won this grand prize, followed by 63 getting a special excellence award, 137 with an excellence award, 31 special excellence industry awards and 46 excellence industry awards. This did make me wonder whether anyone was left without a prize, but also underlined the achievement of IS design in getting the top award. It also highlights how many builders in Japan are thinking about energy, and is also a reminder of just how many builders there are in this country! The list may be useful to anyone looking for a low-energy builder. Many of the builders are small, and you would need to be in their area, which is not listed explicitly.

​ An interesting feature of the list of award winners is the climate region. Japan is divided ​into 8 climate zones from 1 in the North of Hokkaido to 8 in Okinawa. In the case of small builders, this presumably shows where the building that won the award is. For national builders, presumably it shows where the award-winning building is available. Some builders will only offer some buildings in certain regions. If you are in Hokkaido, the north island, I imagine is it very easy to find a well-insulated house, and in fact it may be difficult to find one that is not well insulated. If you look at the map though, you can see the bottom tip of Hokkaido is the green region 3. And so is the north of Nagano prefecture, which is a large-landlocked prefecture rjght in the middle of the country. In fact Nagano ranges from region 3 in the snowy north to region 5 in the south and there is a marked difference between the energy standards of the buildings. Practically this means that it may be possible to get a smaller builder from the north of the prefecture to build in the south, however some of the national-scale builders may refuse to increase the spec for a building in the south because it is only in region 4 or 5. Some builders pride themselves on offering the same price for their buildings wherever in the country they are built, so their accommodation to the local climate can have implications to their bottom line.

There are more details on exact climate zones of towns and regions in Japanese here.


Below are some observations based purely on the websites of the other three winners, since I haven't had the chance to visit their buildings.

​Shimano Komuten are in ​Koyama City, Tochigi Prefecture. At the top of their website they say they are specialists in highly insulated houses (高断熱住宅). The landing page also mentions airtightness and ventilation. They give six points in building low-energy houses, the first of which is insulation. The second is airtightness, which goes into some detail about the Exel Shannon triple-glazed windows they use. Ventilation is their third point, so they clearly subscribe to the holy trinity of Passivhaus.

Their fourth point is a guarantee to keep monthly energy bills to under 300 yen per tsubo, about ​90 yen per square metre. In the first year, they will pay all the energy bills. In the second year they will cover all energy costs over 300 yen per tsubo, or if the energy bills come under 300 yen, they will give the difference as a gift. I'm not sure if I've translated that correctly, or if it completely makes sense. I guess it gives the homeowner an incentive not to overuse electricity, but it presumably also gives the builder a disincentive to make a house that will use much less than 300 yen per tsubo, but if they're actually putting up their money for the home owner's energy bills, they are obviously serious about it, and presumably have a better idea what those bills will be than most house builders. And those energy bills are pretty low. For reference, my energy bills are under 200 yen per tsubo, assuming the electricity I'm using straight from my solar panels is costing me the same as if I bought it from the grid.

Seidai​ are in Kanazawa city, Ishikawa Prefecture. ​Their building process has ten features: 1) cool in summer and warm in winter; 2) good for the health; 3) easy on the wallet; 4) long lasting; 5) very quiet; 6) strong in earthquakes; 7) flexible in planning; 8) regular consultation; 9) "after follow"; 10) environmentally friendly. ​As a deep green, it annoys me a bit that the environment is number ten on their list, but it's good to see it on the list, and it makes sense to add it after the other items that will have a more direct impact and are likely to be more urgent concerns for their customers.

The finer details include a choice of insulation materials between glass wool, sheep wool, polyester or cellulose. They also talk about airtightness and ventilation. And they too have low-e argon-filled PVC triple glazing from Exel Shannon. They also have a well-ventilated crawl space, which may be OK if it's within the thermal envelope, but I don't really subscribe to the wisdom of the crawl space when you have a modern foundation slab.

Yamato Juken​ are a large-scale builder operating in the Kanto and Kansai areas, on a different scale to the other three grand prize winners. They received the prize for the UW-Y, which is the top of their range, and also won the award in 2014.​

They are a ZEH builder. ZEH is a zero-energy policy which is slated to be a national standard by 2030. I won't go into politics here, but just note that many current politicians may be out of office by then, some of the civil servants may have retired, and slate breaks easily if it is dropped!

Yamato's policy statement talks about bringing Japanese buildings to the world standard, contrasting the average 30-year lifetime of a Japanese house with 141 years in the UK and 96 years in the US. They mention the insulation standards of Germany, and lament that while Japan produces cars and electronic goods to world standards, its buildings fall far behind.

They talk about airtightness and insulation for a healthy house. Strong houses to protect your family. Placing importance on the ideas of the customer. A commitment to health. A price you can trust that will put your mind at rest.

Looking in the details, they also have Exel Shannon's triple-glazed low-E argon filled windows. IS Design use these windows as well, which puts them in all four grand prize winners.


In their details on insulation and airtightness, I couldn't help noticing an obvious gap in the thermal envelope where they have insulated the house on the outside and the crawl space on the inside. The caption in the house says there is nowhere for the cool or warm air to escape, but can you spot it? If they can't get that right on a graphic, I worry whether they could get it right on an actual building!