重庆市区居住建筑空调季节夜间通风节能潜力分析

夜间通风,不仅存在很大的节能潜力,而且有健康效益。通过对重庆市夜间温、湿度环境和风环境综合分析,探讨了重庆市空调季节夜间通风的潜力,并根据某大学校园公寓热湿环境测试结果,计算除热能力。最后通过重庆市空调耗电量模型,计算了重庆市空调季节夜间通风节能潜力。

重庆地区绿化屋顶与夜间通风联合作用的降温实验研究

在重庆地区搭建的2个实验箱中进行了绿化屋顶与夜间通风联合作用的隔热降温实验研究,引入室外低温空气通风,以弥补绿化屋顶在夜间会阻止室内热量向室外散发的不足。通过2个实验箱测量数据的对比分析发现,绿化屋顶与夜间通风结合后可显著降低室内温度和屋顶得热量。此外还对室内热环境的影响因素(室外气候参数、绿化屋顶土壤湿度)作了相关性分析。

室内湿度控制模式对夜间通风效果评价的影响

以某高校图书馆为例,分析了EnergyPlus软件的两种室内湿度控制模式对室内湿度和空调负荷预测及夜间通风节能效果评价的影响。结果表明,定湿度模式预测得到的室内湿度与设定值一致,定显热比模式预测得到的室内湿度波动较大,且室内人员密度越大或室内设计温度越低,预测结果偏离设定值越多。两模式算得的空调显热负荷相同,潜热负荷不同,且室内人员密度越大或室内设计温度越低,定湿度模式预测得到的潜热负荷和全热负荷超过定湿度模式的预测结果越多。若该建筑位于上海或西安地区,则典型日的夜间通风节能率均约为9%,且定显热比模式的预测结果稍大。采用定显热比模式计算空调负荷、评价夜间通风节能效果时需同时考虑日间室内湿度是否满足要求,尤其是对湿热地区室内人员密度较大或设计温度较低的建筑。如果室内湿度不满足要求,应采用定湿度模式。

A Predictive Nighttime Ventilation Algorithm to Reduce Energy Use and Peak Demand in an Office Building

The effect of two nighttime ventilation strategies on cooling and heating energy use is investigated for a prototype office building in several northern America climates, using hourly building energy simulation software （DOE2.1E）. The strategies include： scheduled-driven nighttime ventilation and a predictive method for nighttime ventilation. The maximum possible energy savings and peak demand reduction in each climate is analyzed as a function of ventilation rate, indoor-outdoor temperature difference, and building thermal mass. The results show that nighttime ventilation could save up to 32% cooling energy in an office building, while the total energy and peak demand savings for the fan and cooling is about 13% and 10%, respectively. Consequently, finding the optimal control parameters for the nighttime ventilation strategies is very important. The performance of the two strategies varies in different climates. The predictive nighttime ventilation worked better in weather conditions with fairly smooth transition from heating to cooling season.