Night ventilation scheme optimization for an Ultra-low energy consumption building in Shenyang, China

Abstract

The development of low-carbon buildings represented by ultra-low energy consumption buildings has attracted worldwide attention, however the application law and energy-saving potential of night ventilation scheme in ultra-low energy consumption buildings have not been discovered as clearly as traditional buildings. To explore its feasibility and specific technical solutions, the night ventilation scheme of an ultra-low energy consumption building in Shenyang, China is optimized and analyzed. This building with mechanical ventilation and natural ventilation were studied by means of experiment and numerical simulation. Different night ventilation schemes including ventilation volume, frequency, duration and outside weather conditions were considered in the further simulations. The results show that the peak temperature in the ultra-low energy living room is clearly lower than the peak outdoor temperature, and both the peak indoor temperature and the cooling load of the building decrease with the increase of ventilation volume. The optimal night ventilation scheme for the building varies from month to month. The optimal ventilation frequency range is 4–12 times/h for mechanical ventilation. Under the optimized night ventilation mode, the building cooling system energy saving rate increases from June to September with an exception of July, for which the energy saving effect is not obvious under the mechanical ventilation scheme. In addition, the energy saving effect of natural ventilation scheme is better compared with mechanical ventilation. Application of night ventilation in ultra-low energy consumption buildings in Shenyang can greatly reduce the energy demand of the building cooling system. Under the optimized scheme, the annual energy saving is 11.96 kWh/m2. When the outdoor temperature is suitable, it is recommended to adopt natural ventilation at night to achieve better energy saving effect of the cooling system.