Chinese prototype building models for simulating the energy performance of the nationwide building stock

Building energy modeling(BEM)has become increasingly used in building energy conservation research.Prototype building models are developed to represent the typical urban building characteristics of a specific building type,meteorological conditions,and construction year.This study included four residential buildings and 11 commercial buildings to represent nationwide building types in China.With consideration of five climate zones and different construction years corresponding to national standards,a total of 151 prototype building models were developed.The building envelope properties,occupancy and energy-related behaviors,and heating,ventilation,and air-conditioning(HVAC)system characteristics were defined according to the corresponding building energy efficiency design standards,HVAC design standards,and through other sources,such as questionnaire surveys,on-site measurements,and literature,which reflect the real situation of existing buildings in China.Based on the developed prototype buildings,a large database of 9225 models in 270 cities was further developed to facilitate users to simulate building energy in different cities.In conclusion,the developed prototype building models can represent realistic building characteristics and construction practices of the most common residential and commercial buildings in China,serving as an important foundation for BEM.The models can be used for analyses related to building energy conservation research on typical individual buildings,including energy-saving technologies,advanced controls,and new policies,and providing a reference for the development of building energy codes and standards.

Proliferation of district heating using local energy resources through strategic building-stock management： A case study in Fukushima, Japan

District heating systems using cogeneration technology and renewable resources are considered as an effective approach to resources conservation and reduction of greenhouse gas （GHG） emissions. However, wide- spread aging and depopulation problems, as well as the popularization of energy-saving technologies in buildings, are estimated to greatly decrease energy consumption, leading to inefficiency in district heating and barriers to technology proliferation. From a long-term perspective, land use changes, especially the progression of compact city plans, have the potential to offset the decrement in energy consumption that maintains the efficiency of district heating systems. An integrated model is developed in this paper based on building cohort analysis to evaluate the economic feasibility and environmental impact of introdu- cing district heating systems to a long-term compact city plan. As applied to a case in the Soma Region of Fukushima, Japan, potential migration from the suburbs to the central station districts is simulated, where district heating based on gas-fired cogeneration is expected to be introduced. The results indicate that guided migration to produce concentrated centers of population can substan- tially increase the heat demand density, which supports a wider application of district heating systems and better low-carbon performance. These results are further dis- cussed in relation to technology innovation and related policies. It is concluded that policies related to urban land use planning and energy management should be integrated and quantitatively evaluated over the long-term with the aim of supporting urban low-carbon sustainable develop- ment.

Ranking parameters in urban energy models for various building forms and climates using sensitivity analysis

Urban Building Energy Modelling(UBEM)allows us to simulate buildings’energy performances at a larger scale.However,creating a reliable urban-scale energy model of new or existing urban areas can be difficult since the model requires overly detailed input data,which is not necessarily publicly unavailable.Model calibration is a necessary step to reduce the uncertainties and simulation results in order to develop a reliable and accurate UBEM.Due to the concerns over computational resources and the time needed for calibration,a sensitivity analysis is often required to identify the key parameters with the most substantial impact before the calibration is deployed in UBEM.Here,we study the sensitivity of uncertain input parameters that affect the annual heating and cooling energy demand by employing an urban-scale energy model,CitySim.Our goal is to determine the relative influence of each set of input parameters and their interactions on heating and cooling loads for various building forms under different climates.First,we conduct a global sensitivity analysis for annual cooling and heating consumption under different climate conditions.Building upon this,we investigate the changes in input sensitivity to different building forms,focusing on the indices with the largest Total-order sensitivity.Finally,we determine First-order indices and Total-order effects of each input parameter included in the urban building energy model.We also provide tables,showing the important parameters on the annual cooling and heating demand for each climate and each building form.We find that if the desired calibration process require to decrease the number of the inputs to save the computational time and cost,calibrating 5 parameters;temperature set-point,infiltration rate,floor U-value,avg.walls U-value and roof U-value would impact the results over 55%for any climate and any building form.

Drivers and barriers to energy-efficient technologies(EETs)in EU residential buildings

To achieve carbon targets,the European Union(EU)aims to promote nearly zero-energy buildings(nZEB).To enable the necessary transition,technical solutions need to converge with socio-economic factors,such values and awareness of stakeholders involved in the decision-making process.In this light,the aim of this paper is to characterise perceived drivers and barriers to nine energy-efficient technologies(EET),according to key decision-makers’and persuaders of the technology selection in the EU residential building context.Results are collected across eight EU countries,i.e.Belgium(BE),Germany(DE),Spain(ES),France(FR),Italy(IT),Netherlands(NL),Poland(PL),and United Kingdom(UK).The stakeholders’selected are architects,construction companies,engineers,installers and demand-side actors.Data from a multi-country survey is analysed to calculate the share of 15 drivers and 21 barriers(aggregated to 5 groups),being selected for each EET and country.The 5 groups considered to analyse drivers and barriers are environmental,technical,economic,social,legal.The perceived barriers and drivers were further studied for their association across the countries using the Pearson’s Chi2 and a Cramer’s V tests.The results demonstrate that across all EETs and countries,the technical and economic driver groups are perceived to have the highest potential to increase the implementation rate of EET.In terms of barriers,economic aspects are seen as the foremost reason that EET are not scaling faster.In both drivers and barriers legal aspects are the least often selected.In overall the barrier groups show significant variation across countries compared to driver groups.These findings provide an evidence-basis to better understand arguments in favour and against specific EETs and,in this way,support policy makers and other interested parties to increase the market share of the selected solutions.