Pre-cooling Operation For Air Condition System In Auditorium Of Guangzhou Opera House

Air condition in opera was opened before a performance, pre-cooling thermal environment to improve comfort, to reduce the impact of peak cooling load as audiences came into auditorium. However, this operation was not conducive to energy conservation, as well as thermal comfort, because of such existence of the irrationality, as pre-cooling temperature, flow rate, time and other parameters which were set up by operator opinion. Therefore, a research has been carried out to study on pre-cooling operation for air condition in the auditorium of Guangzhou Opera House.A pre-cooling operation model was established to determine three main parameters, including pre-cooling temperature, flow rate and pre-cooling time. Through measurement of temperature, velocity, humidity under different pre-cooling state, and data analysis, it obtained characteristics about cooled airflow and its heat transfer in pre-cooled auditorium, which provided a basis for pre-cooling time calculation. But existing literature did not mention pre-cooling time calculation. Analysis of unsteady flow and heat transfer equations, computational fluid dynamics (CFD) was found that it not only offered a solution, but also improved accuracy. Therefore, CFD was used to determine the pre-cooling time through software Fluent, based on measurement data. If there were a difference between the result and measurement data, the original model would be modified mainly from physical structure and calculation model. And it recalculated the pre-cooling time, simulating the process of airflow, heat transfer.Simulation result showed that a pre-cooling operation was that pre-cooling temperature at 21℃, flow rate in 106000 m3/h in 0.77 hour per-cooling time, then during 2-hour performance, parameters changed as cooling load decreased through Building Automation system in auditorium during a performance. It was proved that there was hardly significant difference between the result and measurement data, and pre-cooling operation was better in thermal comfort and energy conservation than non-pre-cooling operation in that. In addition, using Fluent and DeST software, different programs were set to compare in energy conservation, cost, etc. As a result, an optimization, which was precooling temperature at 22℃, flow rate in 106000 m3/h,51.6 minutes of pre-cooling time, was obtained. Pre-cooling operation model not only determined pre-cooling operation parameters, obtained an optimization, to improve comfort and save energy, but also reflected significantly the benefits of "flat peak", comfort, energy conservation in a pre-cooling operation for air condition.