Building environment simulation before desk top computers in the USA through a personal memory

In the USA, full scale computer applications for HVAC related problems star ted in the early 1960s when the author was involved in the US government's projects to evaluate the thermal environment in fallout shelters by an hour by hour simulation of heat and moisture transfer processes between human o ccupants and the shelter's interior surfaces under a limited ventilation co ndition. General building energy simulations based on hour by hour calculat ions were started a few years later by the gas and electric industries. Thi s led to the formation of the American Society of Heating, Refrigerating an d Air-Conditioning Engineers (ASHRAE) Task Group on Energy Requirements to develop a comprehensive hourly energy performance simulation of buildings, as well as to the activities of automated procedure for engineering consult ants (APEC) for cooling load calculations. These activities eventually deve loped into the formation of four international symposia (Gaithersburg, Banf f, Paris, and Tokyo) on the use of computers for environmental engineering related to buildings, the forerunner of IBPSA. A considerable amount of eff ort went into the earlier thermal simulation programs to improve the physic al and empirical modeling of air, moisture and heat transfer processes in a nd through a complex building structure under varying weather conditions an d building use conditions. Parallel and equally comprehensive efforts were made to improve the simulations of HVAC systems and equipment, and the deve lopment of typical weather data. (C) 2001 Elsevier Science B.V. All rights reserved.