Investigation of Air Recirculation and Thermal Efficiency within a Climate Controlled Passage

Description

Historically, entrances have been used for passage between two separate temperature environments, such as moving from inside to outside of a building. Energy loss through entrances is a cause for concern, as it has been known to increase energy consumption to replace the lost energy; and with the exchange of air masses and cold air entering the building, human discomfort may occur. In this research, thermal efficiency and air circulation within a Conventional Entrance (CE) and Climate Controlled Passage (CCP) are compared.
A small scale model of the CE and CCP was constructed to examine forty-eight energy exchange conditions, emulating those found through an entrance between a temperature controlled lab and the model. Instruments such as a power meter, a flow explorer laser Doppler anemometer, and thermocouples were used to measure and compare the energy consumption, velocity vectors, and temperature energy within the entrance.
Results indicate that the CCP did retain thermal energy compared to the CE. The CE developed sloped isotherm lines and air flow that enabled and maintained thermal exhaust. Conversely, the CCP developed horizontal isotherm lines and a two-layer density current to recirculate and retain thermal energy. The research demonstrates that it is possible to increase energy efficiency of entrances in many applications.
Author Keywords: Air Recirculation, Building, Entrance, Oven, Thermal Energy Efficiency, Two-layer Density Current