Building Energy Performance Analysis Research Articles

제로에너지건축물 계획을 위한 국내외 에너지성능관련 제도의 평가도구 비교분석 및 개선방안 연구

제로에너지건축물 계획을 위한 국내외 에너지성능관련 제도의 평가도구 비교분석 및 개선방안 연구

Evaluation on classroom thermal comfort and energy performance of passive school building by optimizing HVAC control systems

Decreasing the building energy consumption and improving thermal comfort through optimization of heating, ventilation and air conditioning (HVAC) control systems are becoming increasingly significant due to global energy crisis, carbon emission and requirement of high life quality for people. Therefore, evaluation on building energy efficiency and human thermal comfort is extremely necessary. In the present work, energy conservation performance of one passive school building and classroom thermal comfort enhancement will be simultaneously investigated. Energy performance of single reference classroom under six design points and whole school building with two scenarios have been numerically investigated concerning the effects of different indoor set-point temperatures, pre-ventilation, sun-shading system, and the efficiency of the heat recovery facility. Numerical results demonstrate that heating and cooling demands heavily depend on indoor set-point temperature, occupancy and heat recovery rate. Building energy performance analysis illuminates that the optimized control systems for HVAC and sun-shading systems show an expectedly energy efficient performance. In addition, classroom thermal comfort indicated by the recommended thermal range and comfort zone has been numerically and experimentally presented.

Multi-scale Analysis and Optimization of Building Energy Performance – Lessons Learned from Case Studies

The sustainability of the built environment largely depends on its energy and environmental performances. The overall objective, across the different phases of the building life cycle such as design phase, construction phase, commissioning phase, operation phase and eventually refurbishment phase, is to improve building and system performances in terms of economics, comfort, environmental impact and durability.Numerical simulation tools and optimization methods are needed to properly evaluate all the key performance indicators simultaneously, unveiling the existing gaps and identifying possible synergies and strategies in the performance estimation and decision-making processes for the building life cycle.Further, several modelling methodologies have been developed in order to evaluate the energy performance of buildings. Generally, every modelling methodology responds effectively to some specific tasks, but there exists a lack of integration in the overall optimization process.Given the multi-scale and multi-objective nature of the problem of optimization of the energy and environmental performances of the built environment, subject to economic and comfort constraints, an appropriate synthesis and integration process in modelling methodologies has to be identified, addressing realistically the uncertainties inherently present in every modelling strategy.Data analysis and optimization techniques are successfully used in a wide variety of applications. Although these techniques have proven to be successful in both theoretical and applied domains, questions remains about their applicability for the problems introduced before. These questions involve primarily the robustness and efficiency of solutions procedures and the ability to identify relevant properties and to deal with large quantities of data.The paper aims to analyse critically these topics by means of case studies, showing a possible path to create an integrated methodology able to synthesize all the relevant aspects previously mentioned.

Historical trends and current state of heating and cooling degree days in Italy

Degree days (DD) represent a versatile climatic indicator which is commonly used in the analysis of building energy performance, as e.g. (i) to perform energetic assessment of existent and new buildings, (ii) to analyze the territory energy consumption, (iii) to develop scenario analyses in terms of energy consumption forecasting, and so on.Different methods can be used for determining the DD values, depending on the available climatic data of each location. In the present paper, the simplified methods based on reduced climatic data set have been compared assuming the mean daily degree-hours method (MDDH) as reference. Hourly temperature profiles recorded by the meteorological station located at the University of Genoa have been used for these analyses.In the second part of the present work, the ASHRAE method has been selected to calculate heating (HDD) and cooling (CDD) degree days for several Italian cities. In particular, daily meteorological data of several Italian cities (covering the whole climatic conditions which occur in Italy) have been used to calculate heating and cooling degree days in the period 1978–2013, in order to analyze their trends in the last years. Finally, the historical profiles of Rome and Milan have been treated as time-series and analyzed in the frequency domain, performing a decomposition of the original data set into different characterizing components. This simplified approach permits to deeply analyze the historical profile of DD and represents a simple starting point method for future analyses with forecasting perspectives.

Building energy performance analysis: A case study

International standards, in particular the Italian one, evaluate buildings energy performance assuming steady-state working conditions: currently, the study of the energy performance of buildings is based on a simplified calculation that estimates the energy demand using monthly or seasonal average outdoor temperatures. For this reason we have conducted a comparative analysis of the energy performances of an old building using a semi-stationary software and a dynamic one. The studied building is placed in the peripheral part of an historical city located in the center of Italy. We have performed three simulations considering transparent elements characterized by progressively improved properties of thermal transmittance and solar gain factor. A comparison between the outputs of the two codes, in order to highlight the different ways of evaluating the energy contributions to annual energy demand, has been performed. Finally, the models were validated by means of an in-situ measurement campaign using a heat flow meter – in order to measure the thermal transmittance of the opaque walls – and a thermographic camera. This modus operandi allowed us to appreciate how the use of a dynamic software is essential to deal with the inertial properties of the structure and to calculate in an accurate way the annual energy demand.

Heating and cooling building energy demand evaluation; a simplified model and a modified degree days approach

Abstract Degree days represent a versatile climatic indicator which is commonly used in building energy performance analysis. In this context, the present paper proposes a simple dynamic model to simulate heating/cooling energy consumption in buildings. The model consists of several transient energy balance equations for external walls and internal air according to a lumped-capacitance approach and it has been implemented utilizing the Matlab/Simulink® platform. Results are validated by comparison to the outcomes of leading software packages, TRNSYS and Energy Plus. By using the above mentioned model, energy consumption for heating/cooling is analyzed in different locations, showing that for low degree days the inertia effect assumes a paramount importance, affecting the common linear behavior of the building consumption against the standard degree days, especially for cooling energy demand. Cooling energy demand at low cooling degree days (CDDs) is deeply analyzed, highlighting that in this situation other factors, such as solar irradiation, have an important role. To take into account these effects, a correction to CDD is proposed, demonstrating that by considering all the contributions the linear relationship between energy consumption and degree days is maintained.

Impact by Estimation Error of Hourly Horizontal Global Solar Radiation Models on Building Energy Performance Analysis on Building Energy Performance Analysis

Impact by estimation error of hourly horizontal global solar radiation in a weather file on building energy performance was investigated in this study. There are a number of weather parameters in a given weather file, such as dry-bulb, wet-bulb, dew-point temperatures; wind speed and direction; station pressure; and solar radiation. Most of them except for solar radiation can be easily obtained from weather stations located on the sites worldwide. However, most weather stations, also including the ones in South Korea, do not measure solar radiation because the measuring equipment for solar radiation is expensive and difficult to maintain. For this reason, many researchers have studied solar radiation estimation models and suggested to apply them to predict solar radiation for different weather stations in South Korea, where the solar radiation is not measured. However, only a few studies have been conducted to identify the impact caused by estimation errors of various solar radiation models on building energy performance analysis. Therefore, four different weather files using different horizontal global solar radiation data, one using measured global solar radiation, and the other three using estimated global solar radiation models, which are Cloud-cover Radiation Model (CRM), Zhang and Huang Model (ZHM), and Meteorological Radiation Model (MRM) were packed into TRY formatted weather files in this study. These were then used for office building energy simulations to compare their energy consumptions, and the results showed that there were differences in the energy consumptions due to these four different solar radiation data. Additionally, it was found that using hourly solar radiation from the estimation models, which had a similar hourly tendency with the hourly measured solar radiation, was the most important key for precise building energy simulation analysis rather than using the solar models that had the best of the monthly or yearly statistical indices.

Energy consumption and CO2 emission responsibilities of terminal buildings: A case study for the future Istanbul International Airport

Airport terminal buildings are used to be treated as stand-alone buildings for their energy performance. Previous studies in the literature fall short of recognizing functional and physical relations of terminal buildings with landside and airside airport operations. In order to avoid these shortcomings, this paper extends the terminal building energy performance analysis to a broader context and expands the analysis envelope to expose the true impact of a terminal building on energy consumption and the combined emissions that it is responsible for. In this respect, this study investigates whether a green terminal building in a new airport planned for the city of Istanbul with an annual 150 million passenger capacity may off-set the loss of CO2 sequestration potential from cutting at least 657000 trees for the airport construction or not. Additional CO2 emissions corresponding to the estimated longer approach and climb out flights due to the unfavorable site selection have also been considered. This article compares a business as usual type of terminal building with four green terminal building scenarios having different CO2 emission reduction potentials. The first-law and the second-law analysis of thermodynamics have shown that constructing a green terminal building complex may not offset its CO2 emissions responsibility unless a very intensive re-forestation activity is implemented and the site is properly re-selected. As a result, this study has exemplified the essential boundaries for energy consumption analysis envelope for an airport terminal building and its true emissions responsibility.

수평면 전일사량 산출모델이 일사열취득계수 및 창면적비를 고려한 건물 에너지 성능분석에 미치는 영향

수평면 전일사량 산출모델이 일사열취득계수 및 창면적비를 고려한 건물 에너지 성능분석에 미치는 영향

Informing Energy-efficient Building Envelope Design Decisions for Hong Kong

Building envelope is widely recognized as a key factor that influences building energy consumption. However, the bulk of passive envelope research is based in cold climates. It remains largely unknown how building envelope design measures are selected and to what extent building energy efficiency can be improved in hot-humid climate. This paper explores the energy-efficient envelope design measures through the combination of understanding the environment, identifying potential measures, setting up models, running analysis, and making design decisions. The findings should inform building envelope design decisions and support building energy performance analysis in hot-humid climate.

A scenario-based analysis of building energy performance

Inherent to the sustainability discourse is concern about the long-term future. If sustainable, cities must deliver positive benefits over their possibly long lifetime. Yet in formulating guidance and negotiating design choices for urban development, the consideration of uncertainty and potential future adverse conditions leading to failure is difficult to deal with. In this paper an approach to this issue that can inform the planning and/or urban design process is presented. It is based on a scenario analysis methodology (futures analysis), which herein is used to appraise the energy-efficiency strategies currently recommended in the UK planning system and best practice. The built environment is one of the major consumers of energy, and its energy efficiency is thereby central to any attempt to reduce carbon dioxide emissions. Through the analysis, some important factors that could undermine good energy performance emerge. Such findings can lead to the making of decisions that can enhance urban resilience. The first part of the paper provides an overview of the energy-efficient strategies examined, as well as current approaches for considering the evolution of present conditions when planning. The second part presents the futures analysis and its significance is demonstrated through a case study.

An analysis on energy efficiency initiatives in the building stock of Liege, Belgium

Built environment is responsible for 60% of total energy consumption in European countries and 128 million BOE of primary energy in Belgium. The average energy consumption in the residential buildings of Belgium is 70% higher than the EU average and stands at 348kWh/m2/year. Energy Performance Building Directive (EPBD) provides guidelines for energy performance analysis of buildings in Belgium. In this study, a holistic approach has been adopted to analyse the building stock of Liege, Belgium. This analysis is based on ‘General Socio-economic survey 2001’ and ‘Housing quality survey 2006 in Walloon region’ databases. It considers parameters such as buildings age, built-up area, type of heating system, type of fuel used, adjacency, insulation of roofs and walls and energy consumption etc. for an in depth analysis. This study concludes that about 69% of buildings which are constructed before 1945 needs serious renovation towards the improvement of roof and external wall insulation level. It then successfully identifies specific areas which need detailed study to evaluate the comfort status in the existing building stock, improvement of insulation level and its effect on heating energy consumption as well as the economic analysis on energy efficiency measurements.

Building energy performance analysis by an in-house developed dynamic simulation code: An investigation for different case studies

A novel dynamic simulation model for the building envelope energy performance analysis is presented in this paper. This tool helps the investigation of many new building technologies to increase the system energy efficiency and it can be carried out for scientific research purposes. In addition to the yearly heating and cooling load and energy demand, the obtained output is the dynamic temperature profile of indoor air and surfaces and the dynamic profile of the thermal fluxes through the building elements. The presented simulation model is also validated through the BESTEST standard procedure.Several new case studies are developed for assessing, through the presented code, the energy performance of three different building envelopes with several different weather conditions. In particular, dwelling and commercial buildings are analysed. Light and heavyweight envelopes as well as different glazed surfaces areas have been used for every case study. With the achieved results interesting design and operating guidelines can be obtained. Such data have been also compared vs. those calculated by TRNSYS and EnergyPlus. The detected deviation of the obtained results vs. those of such standard tools are almost always lower than 10%.

Energy performance analysis of a solar-cooled building in Tunisia: Passive strategies impact and improvement techniques

The energy performance of a solar cooled office building located in Tunisia is studied using the TRNSYS software. The simulations assessed the real case study and analysed the impact of its architectural characteristics and passive techniques on its energy requirements. The impact of solar passive heating techniques already implemented in the envelope is studied in order to take advantage of them in winter and prevent their overheating effect in summer. Besides, additional passive cooling solutions are proposed and studied aiming to decrease the cooling requirements. The results showed that the insulation of the walls and the cool roof guarantee important savings of 46% in winter and 80% in summer compared to an ordinary building. The study was also focused on the impact of the trombe walls and showed that the heating requirements are raised by 20.7% if the storage walls are omitted from the construction. The integration of internal curtains in the windows and movable solar overhangs shading the storage walls and the low-emissive Argon coatings allowed a relevant reduction in total energy demands: 60.3% for heating demands and 47.7% for cooling demands. The peak cooling load has decreased from an initial value of 14.09–8.68kW. Thanks to this relevant reduction, a technical improvement solution consisting in a cooling storage was proposed to increase the solar cooling performances.

IFCXML Based Automatic Data Input Approach for Building Energy Performance Analysis

To analyze building energy consumption, the building description for building energy performance analysis (BEPA) is required. The required data input for subject building is a basic step in the BEPA process. Since building information modeling (BIM) is applied in the construction industry, the required data for BEPA can be gathered from a single international standard file format like IFCXML. However, in most BEPA processes, since the required data cannot be fully used from the IFCXML file, a building description for BEPA must be created again. This paper proposes IFCXML-based automatic data input approach for BEA. After the required data for BEPA has been defined, automatic data input for BEPA is developed by a prototype system. To evaluate the proposed system, a common BIM file from the BuildingSMART website is applied as a sample model. This system can increase the efficiency and reliability of the BEPA process, since the data input is automatically and efficiently improved by directly using the IFCXML file..

Optimization of Energy Consumption Using BIM-Based Building Energy Performance Analysis

Recently, the interest in increasing energy efficiency of building energy management system (BEMS) has become a high-priority and thus the related studies also increased. In particular, since the energy consumption in terms of heating and cooling system takes a large portion of the energy consumed in buildings, it is strongly required to enhance the energy efficiency through intelligent operation and/or management of HVAC (Heating, Ventilation and Air Conditioning) system. To tackle this issue, this study deals with the BIM (Building Information Modeling)-based energy performance analysis implemented in Energyplus. The BIM model constructed at Revit is updated at Design Builder, adding HVAC models and converted compatibly with the Energyplus environment. And then, the HVAC models are modified throughout the comparison between the energy consumption patterns and the real-time monitoring in-field data. In order to maximize the building energy performance, a genetic algorithm (GA)-based optimization technique is applied to the modified HVAC models. Throughout the proposed building energy simulation, finally, the best optimized HVAC control schedule for the target building can be obtained in the form of “supply air temperature schedule”.

An integrated simulation method for building energy performance assessment in urban environments

The microclimate around a building, establishing through the interaction with other buildings or the natural environment, is a significant factor in the building energy consumption. This paper presents a method for the quantitative analysis of building energy performance under any given urban contexts by linking the microclimate model ENVI-met to the building energy simulation (BES) program EnergyPlus. The full microclimatic factors such as solar radiation, long wave radiation, air temperature, air humidity, and wind speed have been considered in the proposed scheme. A case study has been conducted to analyze the effects of different microclimatic factors on the energy balance of an individual building. The method outlined in this paper could be useful for urban planning and building design.