Comprehensive Evaluation Study On Natural Ventilation Building Performance

Natural ventilation(NV),one of the most effective sustainable technical measures,could reduce building operation energy consumption in an environment-friendly and healthy way.Whether the NV strategy during the building lifecycle can meet the design requirements or not,is the starting and stay point of NV building research.From the perspective of architecture,this paper focuses on the mismatch between design intent and its anticipate effects.We introduce a normative approach that is particularly suited for the assessment of natural ventilation in early design,i.e.when it is important to decide whether the use of natural cooling should be considered in the ensuing stages of design.The normative model requires only a small set of macro identifiers of the intended building and assumes the availability of generic ventilation provisions in terms of size of window openings and suitable window opening control logic.Main research works and achievements are as follows:(1)Theoretical study on building performance assessmentStarting with the NV building performance evaluation methods exploration,this paper makes a comparative study on main components of the evaluation system from the aspects of evaluation purpose,evaluation object,evaluation index,weight system and evaluation result,and then introduces the building performance evaluation system.From the normative calculation method and the performance quantitative evaluation method.the rationality of the building performance evaluation system in the comprehensive evaluation mathematical model construction and subjective judgment substitution method is explained.Through the comparison of constituent elements,built-in functions and performance index analysis,the applicability of the building performance evaluation system to the natural ventilation building evaluation is discussed.Through comparative simulation experiments,the performance and simulation sensitivity of the Energy Performance Calculator(EPC)are tested.Consistent results are obtained by two assessment software(IES and EPC_v_M1.4),and the validity of the EPC_v_M1.4 is confirmed.Combining two derivative softwares(EPC-Calib and EPC-TechOpt),the target building energy-saving renovation is completed,which shows the superiority of EPC_v_M1.4 in energy-saving building simulation analysis.The above research proves the progressiveness of building performance evaluation system in comprehensive evaluation and extendibility.(2)Study on NV oriented building performance evaluation technology platformThough office building model of six representative climate zones worldwide,EPC_v_M1.4 calculation performance on natural ventilation is analyzed,and the influential setting parameters of the natural ventilation potential are obtained.It shows that.in natural ventilation potential assessment,the EPC_v_M1.4 calculation is generally effective yet limited,mainly in the accuracy of the calculation of ventilation heat loss.Embedding logic such as energy reduction calculation,fan energy calculation,and external window opening ratio control in EPC_v_M1.4,the building performance evaluator obust platform,natural ventilation version EPC_v_H2.0:NV is developed to simulate the main NV scenarios:hybrid ventilation(HV),pure natural ventilation(PNV).In the HV scenario,EPC_v_H2.0:NV executes the logic commands of the alternate operation of NV and mechanical ventilation;In the PNV scenario.EPC_v_H2.0:NV executes the logic commands reflecting the coupling relationship of the indoor air temperature,outdoor air temperature and window opening area.Based on the complete building performance evaluation,EPC_v_H2.0:NV can respond sensitively to the influence parameters of NV potential and conduct comprehensive and effective performance analysis of natural ventilated buildings.A calculation performance test of EPC_v_H2.0:NV is executed.To verify the EPC_v_H2.0:NV bottom-engine:EPC,on-site measurements and numerical simulation comparison experiments are carried out.The simulation result is similar to the on-site measurement,which proves that the software has a certain engineering application and popularization value.The analysis of the simulation results of the EnergyPlus and EPC_v_H2.0:NV proves that the simplified logic of EPC_v_H2.0:NV is reasonable and the simulation of NV potential is effective and reliable.(3)Application study on the performance evaluation of natural ventilated medium-sized office building in ChinaThis study consummates the multi-dimensional potential evaluation criteria suitable for China's NV buildings,and tries to establish the operating schedule of the control system,effectively promote the study of NV building control strategy.Based on the simulation analysis of the influencing factors of control strategy and its fluctuation law.the main foreseeable scenarios of NV in buildings are established,one of which include two kinds of HV scenarios considering indoor and ambient temperature difference and himiidity threshold,and a pure NV scenario considering indoor and ambient temperature difference and window opening control logic.The evaluation criteria of NV potential in multi-dimensional buildings are improved:Three composite ventilation standards for measuring available hours,cooling load reduction,and economic benefits are separately established;two pure natural ventilation standards for different acceptability of discomfort are separately established.This paper deals with a major application study supported by the model,which is to establish the natural cooling potential for medium office buildings in different regions of China.The study shows significant cooling reduction potential in most climate regions,followed by verifying the acceptability of buildings relying totally on natural ventilation,i.e.without the presence of mechanical cooling.The general conclusion is that the potential benefit of natural ventilation in China is significant enough to make it an intrinsic part of early design considerations.Moreover,the findings provide guidelines for adapting the Chinese building codes to raise the awareness of natural ventilation options in the all design stages.The innovations of this paper are as follows:(1)Development on the applicability of building performance evaluation system to natural ventilated building evaluation and China green building evaluation theory supplement.(2)Extensive research on building performance evaluator which provides a technical platform for natural ventilated building evaluation.(3)The multi-dimensional potential evaluation criterion improvement which is applicable to natural ventilated buildings in China,control system operation schedules achievement and natural ventilated building control strategy improvement.(4)Natural ventilation cooling potential quantification,natural ventilated building cooling potential distribution map initially construct,and quantitative research optimization of building energy efficiency data.