Research On Evaluation Method Of Natural Ventilation Performance Of Northern High-rise Residential Buildings

With the rapid urbanization and economic growth, the energy consumption ofresidential buildings in China has risen fastly. Enery conservation of residentialbuildings has been paid more and more attention. As a traditional ventilation method,natural ventilation can not only improve indoor air quality, but also reduce the powerconsumption of air conditioning.Natural Ventilation has become an very important measure to reduceenergy consumption of residential building. Literature review shows that moststudies on natural ventilation of residential buildings were focused on CFDsimulation and adpoted indoor air flow distriubion or temperaures as evaluationindicator. However, few studies evaluated natural ventilation performance ofresidential buildings in terms of annual average air change rate and cooling loadsaving ratio.To solve the problem above, the following works have been done inthis paper:Firstly, several improvements of building energy and ventilation couplingsimulation software DeST-VentPlus have been made. Improvements includedthe topology structure process, calculation time reduction, and winde pressureauto-calculation module.Secondly, six high-rise residential building planes have been concludedthrough literature review. Planes can be divided into two major types: slab-typeand tower-type. The natural ventilation simulation procedure and CFD settingshave been introduced in detail.Thirdly, natural ventilation performance simulations of six building planeshave been performed and analysed. The simulation result of18-floor residentialbuildings in Beijing showed that annual average natural ventilation air changerate has reached more than8per hour, which can satisfy the fresh air demand ofresidents. The annual cooling load saving ratio has reached more than60percent, which means that more than7kWh per square meters can be saved bynatural ventilation. The impacts of building plane, ventilation area, buildingdensity, floors, and indoor heat source on natural ventilation performance have been studied through simulation. Natural ventilation air change rate ofSlab-type residential building is larger than that of tower-type. Air change ratelinearly grows with ventilation area. Building density will reduce naturalventialtion air change rate. An air change rate calculation formula has been putforward to calculate the natural ventilation annual average air change rate underdifferent conditions. Besides, log regression formula has been establishedbetween air change rate (N) and cooling load save ratio (ACSR). ACSRs underdifferent Ns can be calculated by the log regression formula.In conclusion, the paper has established a convenient evaluation system ofnatural ventilation performance of northern high-rise residential building,which will be a useful guide for natural ventilation designers.