Paper Conference

Proceedings of ASim Conference 2012: 1st Asia conference of IBPSA-China, Japan, Korea

     

A sensitivity analysis on mixing energy losses in air-conditioned rooms by using CFD

Satoru Iizuka, Syusuke Shiba, Mina Sasaki, Masaya Okumiya

Abstract: In some office buildings, in winter, heating and cooling often operate in perimeter and interior zones simultaneously. In such situations, mixing energy loss often occurs. This loss is defined as the difference between the sum of the net heating/cooling load and that of the actual heating/cooling energy supplied to the air-conditioned room. A mixing energy loss increases the energy consumption of air-conditioning; therefore, it is very important to prevent occurrences of mixing energy loss for energy-saving strategies. In this study, we performed a sensitivity analysis on the mixing energy loss (or mixing energy gain) in air-conditioned rooms by using computational fluid dynamics (CFD) techniques. Particularly, the effects of (1) the setting temperatures in the perimeter and interior zones, (2) the locations of reference temperature points in the perimeter and interior zones, and (3) the shape of air-conditioned room on mixing energy loss (or mixing energy gain) were investigated. To evaluate the mixing energy loss/gain, we conducted two simulations for each test case; one was a simulation without airflow mixing between the perimeter and interior zones, and the other was a simulation with airflow mixing between the two zones. In the simulation without airflow mixing, we introduced a virtual adiabatic wall at the boundary between the perimeter and interior zones. In the simulation with airflow mixing, on the other hand, we removed the virtual adiabatic wall. Finally, by comparing the sensible heat loads between the two simulations (the cases with and without airflow mixing), the mixing energy loss/gain was estimated.
Pages: 651 - 658
Paper:
asim2012_0070