3823 -- Unsteady-State Thermal Analysis of a Large Space with Vertical Temperature Distribution PDF

An unsteady-state analytical model is presented for evaluating the dynamic thermal environment of a large space with vertical temperature distribution. In this model, air currents along vertical walls generated by convective heat transfer are evaluated. The path of supply air jets and the volume of entrained air when the space is air conditioned are evaluated. A thermal network model is included to calculate transient wall temperatures. To verify the model, three experiments were conducted using a test room measuring 3m by 3m by 2.5, - a natural convection experiment, an occupied-zone cooling experiment, and an ON-OFF controlled heating experiment. In all experiments, calculated values agreed well with measured values. The results of the thermal analysis indicate that in a large space with a vertical temperature difference, the influence of radiant heat transfer between wall surfaces is substantial. The presented method was also found to be practical in terms of computation time.

KEYWORDS: non steady state, heat flow, calculating, vertical, temperature distribution, air movement, walls, air inlets, entrainment, air conditioning, transient, temperature, experiment, climate chambers, natural convection, comparing, cooling, heating, radiating, air flow