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Week 2: Solar Radiation, Wind, Temperature, and Relative Humidity

Lecture 1: Solar Radiation

The week 2 assigment is due by July 14. There are 3 peer assesments due by July 21. Lecture slides are here. Again, there's a bunch more resource links on the EdX page. Lots of the comprehension questions use Climaplus.

See Typical Meteorological Year on Wikipedia for a bit more detail than is in the lecture. I think these are the typical data files used in simulation, etc. Downside is they don't account well for outliers. You can get them worldwide here (looks like they do have them for my home city as well).

Take note of the concept of microclimate. You can have a dramatic change in weather data with a small change in location. This kind of thing is less reflected in these weather data files and relies on local knowledge.

There's some interesting discussion around "Low e" coatings/glazings on windows and when you might want to take advatange of non-visible radiation from the sun vs exclude it. At random I watched this youtube video as a demo on the topic.

A very interesting fact from the slides is that you can have 100% daylighting during office hours up to 60 deg north across the world (where 95% of the world's population live).

Good word: analemma. A picture of the sun at the same time of day every day for a year.

Lecture 2: Wind and Wind Power

Slides here.

Very cool wind visualization. Wind information is always stored in the weather files mentioned above. The discussion of residential wind turbines is interesting. Apparently $50-80,000 gets you a turbine that could provide around 13,000 kWh / year (which could be about 1 household). The big ones can provide energy for ~200 households. Here's some information re power sources more specific to Canada. Another interesting link.

I find it interesting the ways ASHRAE comes up in this class as I had never heard of them before my current job. I guess they are a big deal in this field.

The point that Fahrenheit is a more practical range than Celcius or Kelvin is an interesting one I hadn't heard before. The idea being that 0-100 F goes from "really cold outside" to "really hot outside", but 0-100 C is "fairly cold outside" to "you are dead", and 0-100 K is "you are dead" to "you are dead". This class still tends to use Celcius.

Note dry bulb vs wet bulb temperature. Dry bulb is from an ordinary thermometer. Wet bulb: imagine putting a wet sock around the thermometer. This tends to be a cooler reading because of evaporation (if its very humid, there would be no change). Here's a potentially useful resource.

Seasonal ice storage in buildings is not a concept I had heard of. We can dig a big hole and fill it with snow in the winter and then in the summer let a bit of it melt and we have free cooling.

Psychrometric charts are scary. It's a graph of the physical properties of moist air at some constant pressure (usually sea level). If we know two idependent properties of a unit of moist air we can use the chart to determine a number of others. "The HVAC engineers best friend". I don't understand them enough to answer the comprehension question.

The case study of Mantioba Hydro Place is very cool. I'd love to see the building in person some time.

Assignment: Shading Studies and Sun Path Diagrams

The assignment itself is due July 14, and then there is peer grading to be completed by July 21.

The "free software" track uses 3dslash and 3d Sun Path. The "professional" track uses Rhino 6 and ClimateStudio (I think).

I worked through the first tutorial in the Rhino User Guide here as a kind of intro to Rhino. I think I'm at a point where I could build a basic shape as required for the assignment. My first question was is this something I could use something FOSS like Blender for, instead of paid software like Rhino (I have ~40 days left on the trial). Looks like the kind of modeling Rhino is for, called NURBS, isn't well supported by any open source software. NURBS represents everything with points and parametric curves as opposed to polygonal modeling with Blender (I'm sure I'm butchering the distinction). So looks like I'm stuck with Rhino.

I ended up using my model created in Rhino but did the daylight simulations in the free tool.

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