Lesson -1: Principles of Eco-Design(Part One)

                From all the many theories behind environmental design, this section pulls out just a few core ideas. They are all important, and they provide the tools for approaching most design challenges:

1. Using the sun   
2. Thermal mass
3. Stack effect
4. Thermal zoning
5. Embodied energy

1.Using the sun-

• orient the house within 30 degrees of due south-due south is the equivalent of 100% potential solar heat gain through windows. Rotating the house to within 30 degrees of due south still provides about 90% of the potential solar gain and allows latitude for adjusting the house to lot limitations. Much further than 30 degrees starts to make architectural shading difficult and can lead to overheating;

          -only surfaces facing South receive sun all year round, the dominant direction of the sun  is from the South, especially in winter,for this reason, solar panels and windows that will capture solar warming in winter, should face as close to South as possible, solar receipts start to fall noticeably outside the band South-South-East to South-South-West, surfaces facing South-East or South-West receive 10% less solar energy during the year than surfaces facing due South;

- surfaces facing North are in the shade all year round,while most sun is received in the arc South East to South West, the adjacent quadrant, North-East to North-West, receives very little sun except at the peak of summer,for this reason solar design concentrates insulation and minimises glazing on this side of a house, new build solar houses often bury this side of the house in the ground and put all glazing on the South side of the house;

-the winter sun is low, the summer sun is high,vertical South facing windows work best for maximising solar heating in the winter as they capture the low winter sun,some solar  houses even have their windows angled 11 degrees back from the vertical to perfectly face the winter sun.

- surfaces that are more horizontal receive most of their sun in the summer, this is a problem for glazed roofs and skylights which receive little sun in winter but may well overheat rooms in summer,they usually need special shading or air vents (more on the design of roofs for porches and conservatories),the angle which receives the most sun across the year is, not surprisingly, 45°,for this reason it makes excellent sense to mount solar panels flush with a pitched roof;

-the high summer sun is a blessing when if comes to designing shading for vertical windows, only a small overhang is being needed to completely shade a vertical South facing windows in summer, this is another strong argument for maximising South facing glazing, East and West facing windows can be a huge nuisance in summer, they receive no direct sun in winter, but they fully face the low evening and morning sun in summer, West facing rooms are particularly prone to overheating and will need curtains or shades;

• use design software to optimize passive solar heating-this is a very important part if we want to make the house to work like a system, that we will discuss in a future lesson because this part  needs a lot more details like: softwares available,tutorials on how to use them and interpret the results and also integrate the results in our design/drawing scheme;