110 research outputs found
The Present and Future Energy Performance of the First Passivhaus Project in the Gulf Region
With voluntary and mandatory energy performance standards now becoming more common around the world, schemes to develop low energy buildings have become more apparent in developed countries. The Passivhaus standard, established 25 years ago in Germany, is one the most stringent and promising low energy building standards in Europe. It started as a construction concept applied to residential buildings, but has since spread as a voluntary ultra-low energy efficient standard to different parts of the world. Qatar, a member of the Gulf Cooperation Council (GCC) states, announced in 2013 the completion of the first Passivhaus project in the Gulf Region. The current and future performance of the Passivhaus project in Qatar was investigated in this study using current and future climate scenarios. Computer modelling was used to simulate the energy performance of the house and the thermal comfort of the occupants. In addition, on-site measurements were made to corroborate the modelling outcomes. Further, the impacts of climate change on the Passivhaus project was examined, and comparative analyses were undertaken. The findings suggested that the Passivhaus performs well under the current and the future weather data sets. Furthermore, the modelling indicates that the Qatar house is close to achieving the Passivhaus standard
Climate adaptive building shells for office buildings in Egypt: a parametric and algorithmic daylight tool
There is an emerging need to include sustainability–related performance features within the conceptual design stages of a building, especially for parameters such as daylighting and energy usage. Advances in digital architectural design now mean there are innovative possibilities for designing and evaluating dynamic façades capable of generating predetermined environmental performance criteria within a space. It is possible to update the traditional concept of the building envelope from acting not as a passive barrier but as an active negotiator with the surrounding environment. A framework is introduced in which the interdisciplinary integration and performance optimization of climate adaptive building shells (CABS), inspired by traditional Egyptian patterns, were synthesized to evaluate a wide range of façade design alternatives. A multi-objective optimization model for shape exploration is presented to assist designers in creating performance-driven forms at the early design stages. Daylighting was the key performance criterion used to design a CABS system using parametric design and optimization tools for an office space in Cairo, Egypt. The results demonstrated that the CABS system could achieve the desired daylight criteria using its own predefined capabilities
Thermal comfort analysis for the first Passivhaus in Qatar
The Passivhaus standard is a well-established energy efficient standard, initially developed for central European countries, where heating is the dominant building requirement. The success of the Passivhaus standard has attracted the attention of architects and engineers around the world, including Qatar. Qatar has recently announced the first Passivhaus project in the MENA region. The project is experimental in nature - two villas have been constructed side-by-side, one according to the Passivhaus standard and the other according to conventional construction practices in the country. The objective of the study is to test the environmental performance of the Passivhaus standard in a hot and arid climate. The performance of the two villas has been analysed using the IES-VE building performance simulation tool, with the focus on the thermal comfort of the indoor environment. The indoor temperature and relative humidity were the main indicators of occupant comfort levels. Annual hourly data were analysed and, in addition, a detailed analysis of the occupied spaces in both villas on the typically hottest and coldest days of the year was undertaken. The findings indicated a consistent and more uniform level of comfort in the Passivhaus model compared to the standard base model; additionally, the cooling energy requirements to achieve comfort in the Passivhaus villa could frequently be met by the villa’s own on-site renewable energy system. Initial findings suggest that the Passivhaus standard is potentially viable in a hot and arid climate
Combining noise mapping and ventilation performance for non-domestic buildings in an urban area
Maximising the natural ventilation of a building can be beneficial in terms of comfort and reduced reliance on air-conditioning. However, in urban areas this can conflict with the need to reduce the ingress of external noise. In this paper a method is presented to quantify the interaction of building noise exposure with natural ventilation potential. Finite element models of ventilation aperture sound reduction index were used to determine façade sound insulation values for naturally ventilated buildings in two locations. Road traffic noise levels at the building façade were obtained from a calculated noise map of Manchester (UK). Window openings were adjusted in the thermal simulation package and modelled with mixed mode cooling ventilation strategies (both natural and mechanical). This enabled noise considerations to be quantified in terms of building ventilation and energy use for cooling at the whole building level. For a tolerated internal road noise ingress of 34 dB(A) cooling energy consumption for the example buildings in the quieter noise locations was found to decrease by 22%–45% compared to the noisier locations. Most importantly, the introduction of noise reduction measures equal to 10 dB(A) resulted in reductions in cooling energy consumption that varied from 28% to 45% of the original cooling energy consumption. This study illustrates the importance of an integrated approach to both noise exposure and ventilation performance in urban buildings
Exploiting BIM in energy efficient domestic retrofit: evaluation of benefits and barriers
Energy efficient retrofit of the building stock is an important and contemporary issue in the built environment. Building Information Modelling (BIM) can offer a comprehensive and integrating platform for construction projects, as has been demonstrated for many large-scale schemes, mostly in new buildings but sometime also in retrofit projects. This research focuses on the potential of adopting BIM through a smaller scale activity of residential retrofit to achieve energy efficient housing. Although many strategies and technologies have been developed during the last decades, retrofit processes are still confronted by technical, economic and social challenges. This paper investigates how BIM may be integrated all the way through the residential retrofit process and how new digital technology can be engaged. The potential strengths and weaknesses of BIM implementation in retrofitting are identified. This paper is part of an on-going research study and the outcomes from this research will be used to develop a framework which enables informed decisions to be made in retrofitting schemes, and which actively engages BIM into the retrofit process to support automation at retrofitting stages
Experimental setup of continuous ultrasonic monitoring for corrosion assessment
The paper is devoted to the ultrasonic monitoring of accelerated corrosion. In order to achieve non-uniform corrosion (high surface roughness), passivation was applied to the corroding surface. A dedicated electronic multiplexed four channel front end was developed in order to feed the amplified waveforms from several transducers to the recording instrument. The experiment was conducted using two 5 MHz and two 10 MHz ultrasonic transducers all operating in the pulse echo mode. The transducers were excited in turn using gated bursts, and the received echoes were multiplexed and amplified before being digitized by a high accuracy ultrasonic instrument. Application of adaptive cross correlation to the recorded data allowed continuous thickness estimation of the non-uniformly corroded surface whilst cross correlation method gave unsatisfactory results
Using Tilted Façade to Reduce Thermal Discomfort in a UK Passivhaus Dwelling for a Warming Climate
© 2015 The Authors. This study investigated the potential negative impacts of future UK climate change on dwellings. In particular, the risk of overheating was considered for a Passivhaus dwelling in London. The study used dynamic simulation modelling software to investigate the potential use of building geometry to control current and future overheating risks in the dwelling for London climate. Specifically, the focus was on the optimum inclination of a south façade to make use of the building's shape to self-protect itself. A range of different inclined façades were examined to test their effectiveness in reducing the overheating risk. The research found that implementing a 115° tilted façade could completely eliminate the risk of overheating in current climate, but with some consequence for natural ventilation and daylighting. Future overheating was significantly reduced by the tilted façade. However, geometric considerations could not eradicate completely the risk of overheating particularly by the 2080s. The study also used CFD modelling and sensitivity analysis to investigate the effect of the façade geometry on the wind pressure distributions on and around the building surface. This was done to assess natural ventilation flows for alternative façade inclinations
All-optical scanning acoustic microscope
In this thesis a new instrument, the all-optical scanning acoustic microscope (O-SAM) is presented, it is a non contact scanning acoustic microscope (SAM) which uses lasers to both generate and detect surface acoustics waves (SAWs) The non contact nature of the O-SAM overcomes some difficulties associated with conventional SAMs because of the couplant and surface contact involved. This O-SAM also overcomes many of the problems associated with conventional laser ultrasound systems including those of sample damage and ablation, low signal to noise ratio and slow data acquisition. Furthermore, the instrument is adaptive enabling it to compensate to acoustic aberrations that can occur as a result of material microstructure. We believe this is a most significant feature that will greatly enhance its range of applications. This thesis examines some of the key technological developments required to develop the O-SAM, including the use of tailored optical generation pattern realised through the use of a spatial light modulator (SLM) and the development of a novel high speed analogue data acquisition system. This thesis presents the design and construction of the instrument and demonstrates its imaging capability on engineering materials using SAWs at 82 and 164MHz although the instrument is potentially capable of imaging at much higher frequencies. Images are presented on ceramic, steel and aluminium samples which demonstrate a range of contrast mechanisms and measurement techniques, including the interaction of the material with Rayleigh waves and Lamb modes for the purpose of defect detection and characterisation, and measurement of local variations in residual surface stress, changes in coating thickness, and plate thickness
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