scope:

INTRODUCTION

Stratified air-conditioning is used to air-condition the lower zone of an indoor space (occupied zone), as shown in Figure 1, wherein the thermal parameters of the air-conditioned occupied zone can fulfill thermal environment design standard. With an energy-saving strategy, stratified air-conditioning system removes the heat/thermal load in the occupied zone only; as a result, the refrigeration capacity will be reduced efficiently. The level of the height, where supply air nozzles are installed, is taken as the stratified surface of the airconditioned zone. The stratified height is defined as the height from the stratified surface to the ground. Generally speaking, as long as it meets the requirement of thermal environment design standard, a lower stratified height will be beneficial so as to provide a lower cooling load and improve energy-saving.

However, a lower stratified height might cause an unreasonable air distribution in the air-conditioned zone, which would bring about such side effects as non-uniform temperature distribution, air draft and thermal discomfort in the partial airconditioned zone. Furthermore, since the indoor air distribution is affected by the temperature and velocity of supply air, the quantity and position of the blast nozzles, as well as the size and type of the nozzles should also be considered. To achieve a design with optimal air distribution, these factors should be taken into account. Based on the analysis of the large-space building space studied in this paper, an optimized design methodology is proposed.