Saturday 28 February 2015

Smart grid - maybe smarter if not everything in it is smart

On the other hand, if you're looking at a neighbourhood with lots of houses with solar panels on their roofs, you may not want them all to be at the optimum angle and orientation. If they're all the same, you're going to get one peak generation, probably around lunch time.

If some are pointing more to the east, and some more to the west, then each will peak at a different time, helping to balance the supply. A roof at the optimum angle will produce the maximum output over the year, probably peaking in May and September when the angle of the midday sun is close to the average for the year. Shallower roofs will produce less in the winter and more in the summer, so a range of angles may also help to balance the supply.

And there may be more levelling of the emerging grid with different kinds of panels, with their performance depending on the weather conditions. For example mono crystalline will produce more electricity than other panels in low light and in high temperatures.

So thinking of the bigger picture, and thinking long term when solar panels are so cheap that people can't afford not to put them on their roofs and they want to switch the big power stations offline, all those arrays at non-optimal angles make a little more sense. And anyway, going fifteen degrees either way from the ideal due-south 35 degree inclined plane is not going to make a huge difference.

Wednesday 25 February 2015

Low Energy Building - a fifteen week course

From October I'm teaching a course on low-energy building, ninety minutes a week for the fifteen-week semester. I just submitted a syllabus and am waiting for some comments and corrections to come back. It went something like this:

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 cheaper to run. 

This course will introduce students to the principles, practicalities, and the future of low-energy building. 

...

The course will introduce some simple scientific principles and their effect on buildings. We will also look at the design process, and compromise, optimisation and guesstimates. 

Here is an outline of the course. This may change depending on the needs and interests of the class.

1. What is a low-energy building?
2. What is energy?
3. Insulation and thermal envelopes
4. Windows
5. Energy standards and low-energy building around the world
6. Economics and ecology, Embodied carbon and Life Cycle Analysis
7. Thermal bridges and thermography
8. Ventilation and airtightness
9. Heat and moisture
10. Some examples of low-energy buildings
11. To zero energy and beyond: Buildings as solar generators
12. Heating, domestic hot water and other energy hogs
13. Retrofitting and the future
14. Calculation, simulation and measurement
15. Review

I was going to add this lesson: "Policy making around the world" but it looked a bit boring. 

Also in the syllabus I wrote something about the class being in English, but that questions, presentations and homework in Japanese would be fine. I'm hoping that the class will attract students who are good at English, and students who are interested in low-energy building, but worry that there may be a vanishingly small group who are both! 

And the class is going to be open to members of the local community as well as students.

In the first lesson, I hope to discover the knowledge, preconceptions and expectations of the students. Also I'll introduce the key concepts of low-energy buildings and main factors affecting energy use. 

There are another few months to think about the other fourteen lessons.