Using whole building simulation models and optimizing procedures to optimize building envelope design with respect to energy consumption and indoor enviroment

Even though simulation is being increasingly used in design of modern buildings, the full potential of simulation is usually not achieved. To improve building and HVAC system performance, designers usually guess different values of design parameters and then redo the simulation without actual knowing if the guessed value will lead to improvement. This is inefficient and labor intensive. In addition, if the number of design parameters being varied exceeds two or three, the designer can be overwhelmed in trying to understand the nonlinear interactions of the parameters. However, techniques exist that allow automatic, multidimensional optimization of a simulation model, leading to better design with less effort. In this paper, we describe how an optimization can be done using the generic optimization program "GenOpt" and the simulation program "EnergyPlus". In our case study, the optimization yields 22 % energy savings related to the actual design energy consumption. The measures found by using optimization not only decrease operating costs, but also lead to better daylight usage and thermal comfort,  which  results  in  higher  comfort  for  the building occupants