DEVELOPMENT OF A HYBRID VENTILATION SYSTEM USING NATURAL NIGHT TIME VENTILATION FOR CLEVELAND,

This paper presents the development of a hybrid system involving both conventional HVAC systems and natural ventilation as a viable solution to energy consumption issues. Whereas conventional systems are more energy consuming, the fact remains that control of indoor conditions cannot be exercised by simply opening and shutting of windows and other openings. The considerations to be made towards the needs of the building users suggest that a single system, i.e., mechanical or natural, cannot remedy all the issues. A theoretical framework of the hybrid HVAC system with natural night ventilation serving as the natural component of the system is developed in this study. A model for calculation of indoor temperature after night cooling has been formulated. This is done with the aim of using internal room temperature as an index of thermal comfort of the occupants. Accordingly, a model is developed for the final temperature by incorporating the heat gains / losses observed in a building unit. The model requires extensive time consuming calculations for solar radiance, and consequently, the resulting heat gain components. The model is applied to develop night cooling times on a monthly basis for Cleveland, Ohio