Now showing 1 - 10 of 18
  • Publication
    Optimising Life Cycle Energy Performance of Housing: The Value of Occupancy Control
    (Les Presses de l'Université Laval, 2009-06-22) ;
    There is a trend towards reducing heating and cooling requirements of buildings by using high levels of insulation, minimizing thermal bridging, and ensuring excellent air tightness, together with the operation of efficient mechanical ventilation heat recovery (MVHR) systems. In temperate climates, this approach has already raised questions about potential risks of over-specifying some construction elements and installations. This study argues that in maritime climates, appropriate building design with occupant controlled natural ventilation could provide an optimum life cycle energy performance. A heating demand analysis of a sample case study house with MVHR and of the same case study with naturally ventilation is presented, testing different levels of insulation for each case. Embodied energy data of the additional envelope insulation and the MVHR system is added to the operational energy , and the options are compared from a life cycle perspective.
  • Publication
    Building Manager Requirement Specifications for Efficient Building Operation
    Building management plays a significant role in an organisation aiming to achieve an energy efficient status. In this context, there is growing pressure on building managers to provide not only high-quality building services, but to run and manage buildings as economically and efficiently as possible. As such, management activities require a comprehensive data management system to capture, retrieve and put to optimal use, information related to building performance. In this scenario, Building Information Modelling (BIM) can play the role of data repository and provide easy access to information pertaining to precise equipment locations, equipment affected by a system failure, maintenance history information, etc. Therefore, this paper uses building manager’s business processes and associated information identified throughout the paper to propose a BIM-based building management framework that enables accumulation and management of energy life-cycle data based on Industry Foundations Classes (IFC).
  • Publication
    Sensitivity Analysis of the EPBD Energy Performance Grading of Buildings
    (Heliotopos Conferences, 2007-09) ; ;
    The Energy Performance of Buildings Directive (EPBD) obligates EU member states to develop a reliable methodology capable of calculating and certifying the energy performance (EP) of their building stock. In this paper, studies on a series of school buildings, based on Standard prEN15217:2005, consider the impact that a lack of transparency in the data gathering procedure might have on the repeatability of the EP grades. The results showed that variations in EP grades ranging from 0.06 to 1.06 EP grades were possible. The sensitivity of prEN15217: 2005 to variations of input parameters was also investigated and was found to be most sensitive to air change rates and boiler efficiency with grade changes of up to 1.5 grades possible. It was also found that prEN15217:2005 was not heavily influenced by improvements in roof and window specifications.
  • Publication
    Sensitivity analysis of a maritime located night ventilated library building
    (National Technical University of Athena, 2005-05-19) ; ;
    This paper assesses the role of design and operational parameters in a night ventilated library building that has been designed for a maritime type climate. The design rationale behind the building is elaborated and decisions associated with the various design parameters discussed. A model of the building is created using the ESPr simulation program which after experimental validation is used to carry out parametric and sensitivity studies on the building. The role of different building design and operational parameters are examined including building mass, external gains, internal gains, ventilation duration, ventilation rates, as well as ventilation operational strategies.
  • Publication
    Life Cycle Energy Performance: Exploring the limits of passive low energy buildings
    (ASN Events, 2008-09-21) ;
    There is an increasing trend in reducing energy demand of buildings by improving building envelope thermal characteristics. Proven construction examples as used with the German PassivHaus standard achieve substantial reductions on the heating demand compared to mainstream construction, generally by using high levels of insulation together with ensuring excellent air tightness and minimizing of thermal bridges. However, the limits to which levels of insulation in a building can be increased and still represent overall life cycle energy savings are not clear. Particularly for temperate climates, adopting very-high insulation standards can lead to a danger of over specifying construction elements: once we reach certain levels of insulation, any extra material used can have larger energy costs or “embodied energy” than the energy it saves in the life cycle of the building. This paper presents the heating energy use of sample houses in the Irish maritime climate, and analyses the life cycle energy use including the embodied energy of the materials used. A 50-year perspective is presented, and conclusions about the limits to which the heating energy consumption can be lowered by “passive” means on a particular climate are drawn. This paper demonstrates the life-cycle benefits of optimizing the building design ensuring a correct orientation and sizing of the openings, but respecting certain limits when using energy intensive insulation materials.
  • Publication
    Extending IFC to support thermal comfort prediction during design
    (European Council on Computing in Construction, 2019-07-12) ; ; ; ; ;
    During the early design stage, designers often rely on general rules of thumb to make critical decisions about the geometry, construction systems and materials without fully evaluating their effects on indoor thermal environment requirements and constraints. Currently, reviewing a design’s sustainability requires designers to spend a significant amount of time manually extracting Thermal Comfort (TC) data from BIMs because of the tedious nature of this task. This paper is motivated by the absence of a standard method and a schema for extracting the necessary data for an automated TC assessment of building designs. The aim is to generate a reusable and retrievable set of Exchange Requirement’s for BIM-based BTCS to facilitate efficient data extraction and exchanges from design models using the IFC file format. Furthermore, we develop an MVD mechanism that provides a structured framework for the definition and exchange of the target data as a step towards standardisation and production of BTCS related information, the results from which contribute to a proposed MVD. The application of the MVD in building design has the potential to improve the early-stage TC assessment of design alternatives. Further, it could reduce the time required to conduct the assessment, increase the reproducibility of results, and formalises the method used.
  • Publication
    Development of a Model View Definition (MVD) for thermal comfort analysis in commercial buildings using BIM and EnergyPlus
    (Construction IT Allance of Ireland, 2017-11-24) ; ; ; ;
    Buildings are major consumers of global energy resources. Approximately 80% of the energy used in commercial office spaces, is typically used for maintaining optimal comfort levels through delivery of heating, cooling, ventilating, and lighting. Building Information Modelling (BIM) has seen a significant uptake by designers in pursuit of sustainable building designs. Furthermore, general BIM systems already contain much of the information that can be further reused for additional project tasks such as thermal comfort analysis. Integration and improvement of information flows between BIM and Building Energy Performance Simulation (BEPS) tools has the capacity to help designers assess building performance under various design conditions. In doing so, assessments of building performance and thermal comfort requires additional representative data about indoor environmental conditions and energy consumption. The process of connecting BIM to energy simulation tools, for the explicit purpose of thermal comfort analysis, requires a well-defined Model View Definition (MVD). MVDs define a subset of the Industry Foundation Classes (IFC) schema, which is needed to support a particular business process. This paper develops a MVD for thermal comfort that represents the data needed by building designers or operators to deliver a satisfactory level of thermal comfort in a typical small, single occupant office. The use case consists of a single thermal zone with a HVAC system. The detailed specification for these requirements is based on the IFC data representation. The IfcDoc application tool is used to improve the consistency and define computer-interpretable definition of the MVD. The outputs of this work will allow a standardised exchange of the necessary requirements from BIM to BEPS tools (e.g. EnergyPlus) for thermal comfort analysis.
  • Publication
    The transparency and repeatability of building energy performance certification
    The European Union’s (EU) Energy Performance of Buildings Directive (EPBD) aims to increase the energy performance (EP) of buildings by requiring EU Member States to develop an EP calculation methodology and to certify the EP of their buildings. Dynamic simulation offers an important means of developing accurate EP ratings. However, its value may be undermined due to the difficulty in obtaining transparent and repeatable input data on existing buildings. Using the EnergyPlus simulation engine and a DesignBuilder interface this research investigated the impact of this difficulty on the EP grade of four primary school buildings. Survey and on-site refinement phases enabled base case buildings to be modelled, a standard activity schedule to be developed and the lack of transparency and repeatability in the specification of the infiltration air change rate (ACH), the boiler efficiency and glazing parameters to be seen. Using parametric sensitivity analysis in combination with the draft European standard for the energy certification of buildings, prEN15217:2005, it was found that variations in the specification of these parameters could lead to up to two grade changes for boiler efficiency and ACH, one grade change due to the sensitivity of the glazing parameter and three grade changes should their affect be combined. Although repeatability and transparency can be improved through careful training of building EP assessors and the awareness of a particular parameters affect on an EP grade, it will be difficult to ensure repeatability and transparency using a dynamic simulation EP grading methodology if experimental testing is not utilised.
  • Publication
    Whole-Sky Luminance Maps from Calibrated Digital Photography
    (International Solar Energy Society, 2006) ; ;
    Sky luminance is an essential component in assessing the appearance and performance of internal spaces which are highly sensitive to the often dynamic luminance of the visible sector of the sky. Therefore, whole sky luminance distributions representative of real-sky sectoral dynamics over short time intervals are required. A modified scientific-grade digital camera was used to measure whole-sky luminance distributions of various sky conditions. Results showed acceptable correlation between the measured and calculated results for overcast and clear skies demonstrating the viability of using hemispherical digital photography for mapping whole-sky luminance distributions. However, intermediate skies showed distinct sectoral variations and dynamics supporting the argument for more accurate and respresentative luminance distribution data.
  • Publication
    Requirements for BIM-based thermal comfort analysis
    When designing and creating a working or living space, the provision of thermal comfort for a building’s occupants remains a key objective. However, energy consumption associated with the delivery of indoor environmental conditioning in the commercial building stock is not necessarily translated into improved thermal comfort conditions. When collaborative design utilises Building Information Models (BIMs), much of the data required for thermal comfort analysis is already defined by other project stakeholders. Furthermore, mechanical equipment such as HVAC and lighting fixtures, play a major role in functional performance, resultant thermal comfort and energy consumption. Monitoring building performance and thermal comfort requires additional representative data about indoor environmental conditions and energy consumption. This paper presents a holistic review of the data and information needed for the integration of BIM with thermal comfort modelling for commercial office spaces. Thermal comfort is dependent on multiple factors such as indoor environmental conditions, user behaviour, properties of building materials, etc. For inclusion in the design process this data must first be categorised in a standardised manner. The outputs of this work contribute to a Model View Definition (MVD) for thermal comfort using the IFC standard.