Building energy simulation with ease

This paper describes a relatively simple software tool that has been developed to perform annual hour-by hour energy simulation of a building. It extends earlier work performed for one-zone buildings (Bernier and Randriamiarinjatovo, 2001) to buildings that can be represented by five thermally similar zones. The simulation program has been built using a general equation solver (Klein and Alvarado, 2002). As implied by the title of this paper, the solver is easy to use both for the software developer and the user. It provides all the necessary tools (solver, plotting, graphics …) within the same package. The program can accommodate up to five thermal zones: four peripheral zones and an inner zone. The following phenomena are modeled: transient heat transfer through walls (using finite-difference), solar heat gains through windows, internal heat gains, and longwave radiation exchange between inside surfaces. The implementation of these phenomena into the software is discussed. Finally, validation tests performed using ASHRAE’s analytical test suite (Rees et al. , 2002) and the BESTEST diagnostic method (Judkoff and Neymark, 1995) are presented. These results show good agreement with other software tools.