Workshop: Structure of Code II

Lists Redux

Collections

a more complete treatment of lists: mutability, cloning vs. aliasing, lists and loops, double lists, lists and functions

Midterm Project

You will be designing fins for an elliptical tower. Fins are devices that have been used in notable ways, usually to achieve the objective of protecting the surface of a building from direct sunlight and subsequent heat gain. Take some insipiration from these examples in Notable Buildings with Fins .

The main components of this project are the following:

1. Capturing the building geometry
2. Performing a solar incidence analysis on the geometry
3. Designing fins based on the analysis -- making decisions about the number, shape and location

The Geometry

The elliptical tower that you will be working with has the following description:

• it will be sited at the following coordinates: latitude = 40°45' (40.75), longitude = -73°30 (-73.5), timezone = EST (-5.0 GMT)
• The total height of the 30 floor building is 200 meters
• The tower is an extruded ellipse; the elliptical floor plan is centered at the origin and has semimajor axis given by 65 meters (a = 32.5) and semiminor axis given by 110 meters (b = 55).

While the surface is an extrusion, you will be thinking of the surface as a collection of points that mark the vertices of planar glazing units. You are allowed (and encouraged) to consider different spacing and positioning of glazing units along the floors.

Solar Incidence Analysis

Your initial brief will be to use the solar geometry module to analyze how much sunlight is striking the surface of the building. You will be doing this by calculating the beam intensity via Lambert's Cosine Law on each planar element making up your surface (which says that the relative intensity of radiation or light on a surface is proportional to the cosine of the angle of incidence). To familiarize yourself with this kind of analysis, make use of the following function for direct intensity of radiation on a surface normal to the sun vector:

import math
 
#Placeholder function which returns a direct intensity of radiation in the
#normal direction for an input of day in the year and hour of the day 
def directNormalIrad(day, hour):
	return 1000*max(0, -math.cos(hour*math.pi/12) + 1/8.0 - (day-171)**2/115600)
 
 
#Usage
import solarGeom as sg
day = sg.calc_dayOfYear("8/3")
 
for h in range(24):
	print ("for hour "+str(h)
		+", directbeamintensity = "+str(directNormalIrad(day, h))
	      )

In class next week, we will be introducing some basics of reading weather files at which time you will be able to read in measured data for a given day and hour in a year for a set of coordinates. However, the structure of an initial solar incidence analysis will remain the same so make use of this placeholder function for now.

Desigining the Fins

The fins that you will be designing will be planar elements normal to the surface, aligned with either the vertical or horiontal sides of a glazing unit. These fins are understood to be infinitely thin. but can be either vertically or horizontally oriented (or both) and vary in depth.

Decisions about the number, shape and location of the fins will go hand in hand with decisions about what kind and amount of solar incidence data will influence your design. There are other factors such as view or structural capacity of a fin that you may want to incorporate into your design even if these are not explicitly measured.

Deliverables

Final deliverables will be announced next week.

For class on 03.23, it will be good to have tried out each of the three main components of this project. For 1. , it would be good to capture the elliptical tower as a double list where the first index might loop through each floor and capture the points on each floor. For 2. , try calculating the beam intensity on one plane first for a fixed hour of some day. Once you've succeeded doing that, try to iterate across all the planes that make up your geometry and calculate the beam intensity for all the planes for that fixed hour. For 3. Visually represent your analysis by drawing a line normal to each plane that is proportional to the beam intensity. (this is the surface equivalent of the last exercise that we did in the workshop)