Target Students

• 3rd year Undergraduate Students as a Theory Option
• Common to all options in "Sustainable Design"

RATIONALE

Designers are not likely to carry out complicated calculations or computer simulations in the course of their preliminary designs. However, it's precisely during conceptual design that the thermal and comfort performance of a building is irretrievably set. I maintain that it's during this stage that designers must consider the thermal and comfort implications and trade-offs of the decisions being made. As a designer I would rely on my intuitive understanding of thermal phenomena to make the appropriate choices.

Unfortunately for most people our intuitive understanding of thermal phenomena is very limited. This limitation becomes more apparent when the relationships we encounter are counter intuitive. Counter-intuitive results are common occurrences in complex systems, and buildings are indeed complex systems.

Intuitive understanding follows from experience. Through experiences we gradually connect causal relationships; and, as an experience is re-enforced through repetition, we develop an intuitive understanding of cause and effect. Even with this understanding I am often surprised at the results.

We can accelerate our acquisition of intuitive understanding through controlled experiments. We can carry out experiments with full size buildings; with scaled down models; with analog models or with numerical models. The construction and monitoring of a single full size buildings is exceedingly expensive both in terms of money and in terms of time; to achieve a controlled experiment we would need to build as many duplicates of the building as we have parameters we want to control. Scaled down models can reduce the money and time costs; however, they are not appropriate because most interesting effects are size dependent. Analog models are very good for some things but not for all, such as radiant exchange and convection.

Numerical models are the most promising; provided the appropriate physics laws are encoded correctly.

This is exactly the same rationale I used in 1972 to launch DEROB, Dynamic Energy Response Of Buildings. From that date through 1985 I developed and tested DEROB with the support and cooperation of the National Science Foundation, the US Department of Energy and the National Bureau of Standards. As a result, DEROB is one of the most tested and validated energy simulation programs in existence.

Although the fundamental physics has not changed, the capability of digital computers has exploded since then. I have spent the better part of four years recasting not only DEROB but MUSES as well into a new system of programs. This system of programs maintain the rigor of DEROB and MUSES while making them extremely easy to use and interpret.

I propose to use a subset of these programs to serve as the basis of a group of controlled experiments aimed to provide students with the experience that would facilitate the acquisition of intuitive understanding of the principles of thermal comfort and energy performance.

COURSE CONTENT

The following is a list of topics classified according to MUSES and DEROB modules that I will use to run the numerical experiments. Modules that are at least 75% complete will be suitable to run experiments in the context of a course. Under each topic I indicate my estimate of completeness as of this writing.

• Integrated Results
  Code Complete: 95%
  This is the master module that integrates all topics below. It will account for more than 50% of experiments.
• Human Thermal Comfort
  Code Complete: 95%
  It includes human activity, clothing, mean radiant temperature, air velocity, air temperature and humidity.
• Insolation
  Code Complete: 95%
  It includes geometric dependence of direct beam, sky diffused and ground diffused radiation on buildings.
• Physical Properties of Materials
  Code Complete: 95%
  It includes classification of building materials according to their properties and their impact on the thermal performance of buildings. I include the following: thermal conductivity, specific heat capacitance, mass density, index of refraction and skin penetration depth. There will also be experiments to study the incorporation of phase changing materials.
• Internal Activity
  Code Complete: 95%
  This describes the architecture program in terms of the schedule of human activity, appliances and equipment, and electric lighting. The objective is to contrast the thermal effects of internal activity on our conclusions in the absence of this activity.
• Building Geometry and Skin Strategies
  Code Complete: 90%
  This topic will permit to contrast the impact of geometric strategies on the energy and comfort performance of a building. Special strategies will include courtyards and double skins.
• Air Ventilation
  Code Complete: 60%
  It air motion within a space. The model is based on the hydrodynamic equations which represent the principles of mass conservation, momentum conservation and energy conservation as applied to fluids. Although the code is largely complete, it remains to be tested empirically.
• Human Visual comfort
  Code Complete: 50%
  It includes color perception, light intensity, visual contrast and glare.