Optimization of night mechanical ventilation strategy in summer for cooling energy saving based on inverse problem method

Abstract

Night ventilation has great energy saving potentials for public buildings in summer. However, night mechanical ventilation inevitably causes more fan energy consumptions, even though it can reduce the cooling loads for the next day and save the air conditioning energy consumption correspondingly. Thus the optimization of night mechanical ventilation strategy is highly significant for building energy efficiency. In this paper, the simplified two-plate room model is used and the optimization model of the mechanical ventilation and air conditioning system is established. To minimize the total energy consumption, the optimal night ventilation strategy is determined through inverse problem method. Taking an office room in Beijing as the illustrative example, the results show that the optimal air exchange rate for night mechanical ventilation is much higher than the traditional value (ACH ¼ 0.5 h À1) and it highly depends on the indoor-outdoor air temperature difference and cooling load demands. Moreover, the total electricity usage amount can decline from 210 kWh to 111 kWh after optimization, reduced by about 47% in the whole summer season. It also indicates that the energy saving effect of night ventilation mainly derives from the cooling storage and load shifting of building internal walls. Compared to traditional ventilation strategy, the energy saving ratio increases with increasing thermal conductivity and specific heat of building internal walls. This work can provide guidance for practical ventilation system optimization design and operation strategy determination.

Assessment of Summer Overheating in Concrete Block and Cross Laminated Timber Office Buildings in the Severe Cold and Cold Regions of China

“…Solgi et al (2018) showed that night ventilation can effectively improve thermal comfort in buildings in most climate types [59]. Studies have also shown that night ventilation has greater energy saving potential for public buildings in cold climate regions during summer [60,61]. Shading measures can also be used to slow southern overheating.…”

Optimal control of high-rise building mechanical ventilation system for achieving low risk of COVID-19 transmission and ventilative cooling

“…Wang, Yi, & Gao, 2009 ; Y. Zhang, Wang, & Hu, 2018 ). Zhang et al, (2018) proposed an optimal control strategy and investigate the required ventilation rate for mechanical VC through a theoretical model.…”

“… Zhang, Wang, & Hu, 2018 ). Zhang et al, (2018) proposed an optimal control strategy and investigate the required ventilation rate for mechanical VC through a theoretical model. The results show that using mechanical VC, the sum of cooling and ventilation energy consumption can reduce by about 47%.…”

Climatic Cooling Potential Evaluation and Ventilation Strategy Optimization for Building Energy Saving in China

“…While near 1/3 of the total energy usage comes from buildings, including space heating, cooling and ventilation systems [2]. Mechanical ventilation, integrated with free cooling and air-conditioning in summer and transient seasons can effectively save the energy consumption of air conditioning systems [3].…”

“…By making most use of natural cooling sources, climatic ventilation proves to be a good measure to reduce the energy consumption of air conditioning in buildings [3,4]. To determine the ventilation strategy of free cooling and heating, Artmann [5] designated a new index, climatic cooling potential (CCP), according to the indoor and outdoor air temperature difference.…”