Support for the integration of simulation in the European Energy Performance of Buildings Directive

Concerns about the security of energy supply in Europe and the reduction of greenhouse gas emissions led to the introduction of the European Energy Performance of Buildings Directive (EBPD). A key requirement within the EPBD is that Member States will need to adopt a methodology for calculating the integrated energy performance of buildings. This thesis is concerned with the use of detailed energy simulation programs to address this requirement of the EPBD and its possible future evolution

Comparison of the simplified methods of the ISO 13790 standard and detailed modelling programs in a regulatory context

The CEN Standards that support the European Energy Performance of Buildings Directive requirement for calculation of the energy consumption of buildings allow various methods to be used for the same calculation. The impact of using the different methods within the updated ISO 13790 Standard for space heating and cooling energy calculations was examined with a parametric analysis of a common building specification. The impact was assessed by considering the energy band which would be assigned for the building based on the calculation results. The Standard describes three different methods that can be used for the calculations: a monthly quasi-steady state method, a simplified hourly method and detailed simulation. For most cases studied, differences in the building rating given by the various methods were a maximum of one band. More significant differences were noticed in some cases. Parameter values in the monthly method were determined which would lead to improved matching

Impact of using different models in practice - a case study with the simplified methods of ISO 13790 standard and detailed modelling programs

The updated ISO 13790 Standard is part of the new set of CEN Standards that supports the European Energy Performance of Buildings Directive (EPBD) requirement for a general framework for calculation of the energy consumption of buildings. The Standard sets out procedures for space heating and cooling energy calculations, allowing the use of three different methods: a simplified monthly quasi-steady state method, a simple-hourly method and detailed simulation. This paper examines the implications of allowing different methods to be used for assessing the energy usage. The research method used was to undertake a comparison of the various methods applied to a common building specification, with parametric analyses of variations in this specification. The paper discusses differences in results for heating and cooling requirements between the simplified methods and when a detailed simulation program (ESP-r) is used with constrained (according to the Standard) inputs and with a number of unconstrained inputs. The case where two different detailed simulation programs (ESP-r and EnergyPlus) are used in practice for the same building is also included and conclusions are drawn regarding the practical use of different detailed modelling programs against the simplified methods, as well as against each other

A simulation-based framework for a mapping tool that assesses the energy performance of green roofs

This paper presents a framework for the development of a GIS open source mapping tool that aims to disseminate a database with results of detailed simulations in order to assess in a quick and easy way the energy performance of green roof designs across a range of Chinese climates. Detailed simulation results for heating and cooling loads are obtained from the EnergyPlus simulation tool. The study covers 12264 configurations by varying model parameters such as climate, glazing type, roof insulation, soil and plant characteristics, etc. It was found that green roofs can offer significant energy savings if they are applied on roofs without insulation but only limited energy savings where heavy insulation on the roof is also applied. Quick comparisons across a large range of roof characteristics could be easily made with the implementation of the GIS map tool and the design of green roof that fits the specific climate could be optimised without the knowledge of a detailed building energy simulation tool. The critical parameters that affect the green roof’s performance are also highlighted

Integrated dehumidification and downdraft evaporative cooling system for a hot-humid climate

Unlike in hot-dry climates, in hot-humid climates evaporative cooling techniques are not readily suitable for space cooling. In order to effectively use evaporative cooling in hot-humid climates, dehumidification of ambient air is necessary before it passes over an evaporative medium for cooling. The present study explores the combined process of dehumidification and evaporation and its effect on thermal comfort in a typical small residential building located in a hot humid climate. A novel system has been investigated with the combination of an Earth Tube Ventilation (ETV) (for pre-cooling of air), a rotary wheel desiccant dehumidifier (for dehumidification) along with a Passive Downdraught Evaporative Cooling (PDEC) tower (for evaporation) in that order.Parametric simulations using the EnergyPlus tool have been conducted in order to determine the critical dimensions and parameters of the proposed system, such as desiccant system sizing, PDEC tower height, and air and water flow rate at various points of the system. Results of indoor air temperature, humidity levels and volumetric air flow rates in the building spaces were obtained to study the influence of the proposed combined system on human thermal comfort. On a typical hot day the results from the proposed system show a relatively constant indoor air temperature of 28 °C (as opposed to peak indoor temperature of 36 °C occurred by means of natural ventilation) and indoor relative humidity in the range of 62 % - 68 %. The volumetric airflow rate from the outlet of the PDEC tower is in the range of 2.97 - 3.41 m3/s which is well within recommended levels for a dwelling unit. The proposed system displays a significant potential for providing space cooling in hot-humid climates as it paves an alternate way to the conventional energy consuming vapour compression Air Conditioning units

Thermal evaluation of laminated composite phase change material gypsum board under dynamic conditions

Thermal evaluation of non-deform laminated composite phase change material (PCM) gypsum board has been carried out. The theoretical studies covered the analysis of different thicknesses of PCM layers and their corresponding heat transfer rates during energy storage and discharge processes. A simply approach was also provided for determining the appropriate thicknesses of PCM layer under various conditions. For the purpose of experimental study and validation, a laminated gypsum board consisting of a 4 mm PCM layer was evaluated in a naturally ventilated condition. It achieved a maximum heat exchange of 15.6 W/m2 and a maximum energy storage of 363.7 kJ/m2. A model room built with the laminated PCM gypsum boards was also evaluated and achieved a maximum temperature reduction of 5 °C as compared with 1.8 °C for the one with ordinary gypsum board. Even though about 25% of the energy stored could not be released within the targeted period, the overall thermal performance of the PCM gypsum board was quite remarkable. Further heat transfer enhancement mechanism may therefore be necessary for the energy discharge process

Editorial to the Proceedings of the Improving Residential Energy Efficiency International Conference, IREE 2017

Editorial to proceedings of Improving Residential Energy Efficiency International Conference, IREE 2017, 16-17 February 2017, Wollongong, Australi

Implementation of a new bi-directional solar modelling method for complex facades within the ESP-r building simulation program

This paper provides an overview of a new method for modelling the total solar energy transmittance. It is implemented in the ESP-r building simulation program to model complex façades such as double glazed façades with external, internal or integrated shading devices. This new model has been validated and tested for several cases. The new model required changes to the solar control simulation algorithm and the user interface, so a new “Advanced optics menu” was also introduced into ESP-r. The paper presents the interface development and application of the new technique to different simulation configurations (especially different complex façades with shading devices) in a standard office building

Heat transfer analysis of an integrated double skin façade and phase change material blind system

In this study, the heat transfer in an integrated double skin facade (DSF) and phase change material (PCM) blind system has been theoretically analysed. Both heat transfer and airflow models with CFD methods have been developed for the integrated DSF and PCM blind system. Data from an existing typical DSF building have been obtained in order to define input parameters for the simulation exercise and validate the numerical models. The temperature and velocity fields in DSF with the PCM blind system has been predicted under overheating scenario using the ANSYS Workbench FLUENT software and been compared with case of conventional aluminium blind system. This study has shown that the integrated PCM blind system was able to reduce the average air temperature and outlet temperature of the DSF while improving the convective heat transfer between the cavity air and the blades. Compared with the aluminium blind, the PCM blind can absorb large amount of excessive heat in the cavity. Overall the integrated PCM blind system has the potential to be used as an effective thermal management device for minimising the overheating effect in DSFs

Development of high melting temperature microencapsulated phase change material for compacted thermal energy storage bed

In this paper a novel high temperature microencapsulated phase change material (MEPCM) based on paraffin as the core material and MF resin as the shell material has been developed with the in-situ polymerization method for solar hot water storage application. The results showed that the type of emulsifier could influence core material content, the encapsulation efficiency as well as the latent heat capacity. Based on the results and analysis the study has shown that energy storage density could be increased by as much as 59% if 60wt% of MEPCM 1 was to be used in the proposed compacted MEPCM-water bed system