This paper presents the simulations used in designing a major retrofit to a fully conditioned office and classroom building on the University of Hawaii campus so that it is comfortable without air conditioning (compressive cooling). The design and consulting team worked with lighting, daylighting, shading, thermal mass and ventilation strategies so that comfortable conditions are expected to be maintained in classrooms and faculty offices. We developed modeling strategies to work iteratively with the design process to ensure that comfortable conditions can be achieved. This paper specifically describes the modeling strategies used to simulate adaptive comfort algorithms, cross-ventilation modeling, wind tunnel testing and calibration using site weather data.