Showing papers in "Building Services Engineering Research and Technology in 2011"
TL;DR: In this article, a method for the creation of future probabilistic reference years for use within thermal models is discussed, and a comparison is made with the current set of future weather years based on the UKCIP.
Abstract: Weather data are used extensively by building scientists and engineers to study the performance of their designs, help compare design alternatives and ensure compliance with building regulations. Given a changing climate, there is a need to provide data for future years so that practising engineers can investigate the impact of climate change on particular designs and examine any risk the commissioning client might be exposed to. In addition, such files are of use to building scientists in developing generic solutions to problems such as elevated internal temperatures and poor thermal comfort. With the publication of the UK Climate Projections (UKCP09) such data can be created for future years up to 2080 and for various probabilistic projections of climate change by the use of a weather generator. Here, we discuss a method for the creation of future probabilistic reference years for use within thermal models. In addition, a comparison is made with the current set of future weather years based on the UKCIP...
189 citations
TL;DR: The LUCID project as mentioned in this paper developed a series of tools that quantify the effect of urbanization processes on local environmental conditions, and quantify the impact of such conditions on comfort, energy use and health.
Abstract: The urban heat island (UHI) is a well-known effect of urbanisation and is particularly important in world megacities. Overheating in such cities is expected to be exacerbated in the future as a result of further urban growth and climate change. Demonstrating and quantifying the impact of individual design interventions on the UHI is currently difficult using available software tools. The tools developed in the LUCID (‘The Development of a Local Urban Climate Model and its Application to the Intelligent Design of Cities’) research project will enable the related impacts to be better understood, quantified and addressed. This article summarises the relevant literature and reports on the ongoing work of the project. Practical applications: There is a complex relationship between built form, urban processes, local temperature, comfort, energy use and health. The UHI effect is significant and there is a growing recognition of this issue. Developers and planners are seeking advice on design decisions at a variety of scales based on scientifically robust, quantitative methods. The LUCID project has thus developed a series of tools that (1) quantify the effect of urbanisation processes on local environmental conditions, and (2) quantify the impact of such conditions on comfort, energy use and health. The use of such tools is vital, both to inform policy but also to be able to demonstrate compliance with it.
114 citations
TL;DR: In this paper, the authors presented a study of a major open area in a densely built and populated area in the centre of Athens that was part of a Municipality of Athens program to improve thermal comfort conditions in open spaces.
Abstract: The urban heat island effect and its consequences is one of the most important problems cities worldwide have to face in an effort to become more sustainable. This paper presents a study of a major open area in a densely built and populated area in the centre of Athens that was part of a Municipality of Athens program to improve thermal comfort conditions in open spaces. The bioclimatic rehabilitation design process was based on a specific strategy involving detailed monitoring of the thermal characteristics and climatic conditions in the area, extensive analysis of the results in order to define the problem, design and use of efficient passive cooling techniques (cool materials, green spaces, solar control and earth to air heat exchangers), and the use of advanced simulation tools to evaluate and optimise the planed microclimatic improvements. The results indicate that the proposed measures contribute to a decrease in local temperatures of up to 28C for summer conditions. Practical application: The knowledge on perceptions of microclimate in outdoor space can serve as a basis for urban spatial design. To evaluate the application of cool materials in public urban squares. Strategies to improve local microclimate with monitoring and modelling the design features.
98 citations
TL;DR: In this paper, the authors present the results of a questionnaire survey, targeted at almost 2000 homeowners in Southampton on the South coast of England, who bought their home within the first year of the scheme's introduction.
Abstract: Since October 2008, Energy Performance Certificates (EPCs) have been a mandatory requirement for all dwellings sold or rented in England and Wales. Having now been in place for some time, it is of interest to assess the scheme’s impact and effectiveness. This paper presents the results of a questionnaire survey, targeted at almost 2000 homeowners in Southampton on the South coast of England, who bought their home within the first year of the scheme’s introduction. The survey had a response rate of 17% and established homeowner awareness of EPCs, but highlighted that they had little impact on decision-making or price negotiation. Where retrofitting measures have been undertaken, results are inconclusive as to whether retrofitting was done as a result of EPCs. Energy efficiency was not found to be a priority for homebuyers. Practical applications: The survey presented in this paper highlights that further refinement of EPCs and the certification process appear to be needed, in order for the scheme to become a widespread success in the domestic sector. Whilst there is an awareness of the scheme in general, there appears to be limited recognition of its potential. This poses a challenge for the building industry and certification bodies, which need to seek ways to better communicate the benefits of the scheme, in order to instigate the refurbishment works that are required to meet the national carbon emissions reduction targets in the UK.
47 citations
TL;DR: In this article, an approach for quantifying the temperature take back factor is presented, which is of relevance to environmental and energy modelling, and the authors demonstrate that the scale of these interventions is consistent with the emission reductions proposed by the UK Climate Change Committee, and estimate that the consequent reduction in exposure to indoor cold may result in around 4400 fewer disability-adjusted life years each year.
Abstract: Energy used in dwellings is an important target for actions aimed at averting climate change. It is increasingly recognised that these actions may also have near-term effects on health arising from changes to the indoor environment. As part of a major study of such health effects, we modelled hypothetical household energy interventions for the UK of the type and scale needed to meet near-term (nominally 2030) abatement targets. Here, we provide details of the elements of our model that address the relationships between the fabric and ventilation improvements and changes in indoor temperature during the heating season — the ‘temperature take back factor’. We demonstrate that the scale of these interventions is consistent with the emission reductions proposed by the UK Climate Change Committee, and estimate that, in the UK, the consequent reduction in exposure to indoor cold may result in around 4400 fewer disability-adjusted life-years each year. The inclusion of the temperature take back factor for the fabric and ventilation interventions reduces the relevant expected CO2 reductions by ~6%. Practical application: Improvements to the UK housing stock aimed at reducing greenhouse gas emissions will result in changes in internal temperatures. Such changes in temperature have implications for both public health and the prediction of emissions reductions. We present here an approach for quantifying the ‘temperature take back factor’, which is of relevance to environmental and energy modelling.
35 citations
TL;DR: In this paper, a modelling analysis of the role different urban forms might play in reducing building CO2 emissions is presented, which is based on a residential building in a Cairo neighbourhood.
Abstract: This paper describes a modelling analysis of the role different urban forms might play in reducing building CO2 emissions. The study was based on a residential building in a Cairo neighbourhood und...
34 citations
TL;DR: In this article, the use of the latest climate projections from UKCIP (UKCP09 data) and a method of constructing an hourly weather file for the following parameters: dry-bulb temperature, relative humidity, cloud cover, solar irradiation (direct and diffuse), wind speed and wind direction.
Abstract: In the future with climate change, building designers may need to demonstrate to clients that their buildings will continue to provide a comfortable environment under future weather conditions. Building simulation modelling can be used to this end provided that suitable weather files can be constructed. This article describes the use of the latest climate projections from UKCIP (UKCP09 data) and a method of constructing an hourly weather file for the following parameters: dry-bulb temperature, relative humidity, cloud cover, solar irradiation (direct and diffuse), wind speed and wind direction. For a given future scenario, the approach used first selects appropriate months from 3000 years of UKCP09 data to construct a Test Reference Year (TRY). Unfortunately, the UKCP09 hourly data has no wind or cloud data, and the solar irradiance is uncorrected at low sun angles. This article describes algorithms for calculating wind speed and cloud cover from the UKCP09 data. From this data, a TRY can be constructed and formatted to be suitable for use with commonly used simulation packages. Practical applications: Building professionals increasingly seek reassurance on how a proposed building will perform under a future rather than historical climate. This article describes a method of processing the latest future climate projections (UKCP09 data released in June 2009) and generating a Test Reference Year (TRY) with the full complement of weather parameters suitable for use by commonly used building simulation programmes.
29 citations
TL;DR: In this article, a numerical study of the effect of balconies on the capacity for wind-induced natural ventilation is discussed. And the authors also indicate that balconies enhance the cross-ventilation of intermediate floors but weaken that of the ground and top floors by significantly changing the pressure distribution on the windward wall.
Abstract: This article presents a numerical study of ventilation performance of balconies using computational fluid dynamics. The pressure coefficients distributed on the opposite walls of a five-storey building model, both with and without balconies, were studied under variation of the wind direction, balcony dimensions and building height. The effect of balconies on the capacity for wind-induced natural ventilation is discussed. The numerical results show good agreement with the experiments of Chand et al. They also indicate that a balcony enhances the cross-ventilation of intermediate floors but weakens that of the ground and top floors, by significantly changing the pressure distribution on the windward wall. Finally, the ventilation performance of a balcony is not greatly affected by variations in its size but is slightly weakened as the height of the building increases.Practical application: This study provides information and guidance in how best to incorporate the use of a balcony in building development at...
29 citations
TL;DR: In this paper, the authors present the fundamentals in which operation of a 100% outdoor air system integrates with indirect and direct evaporative cooling systems and estimate its energy saving potenti...
Abstract: This study aims to present the fundamentals in which operation of a 100% outdoor air system integrates with indirect and direct evaporative cooling systems and to estimate its energy saving potenti...
23 citations
TL;DR: In this article, the authors combined the CFD technique and Fanger and Toftum's extended PMV-PPD model to investigate numerically the effect of a balcony on thermal comfort for naturally ventilated buildings in tropical-humid regions.
Abstract: The presence of the parapet and floor of a balcony is expected to have a range of effects on a building’s environmental behaviour, in terms of aspects, such as natural ventilation, thermal comfort, pollutant transportation and shading and daylighting. The authors have previously reported that the presence of a balcony can significantly increase the air flow rate of most rooms in a naturally ventilated building. In this study, the CFD technique and Fanger and Toftum’s extended PMV—PPD model are combined to investigate numerically the effect of a balcony on thermal comfort for naturally ventilated buildings in tropical-humid regions. The results show that although a balcony reduces the indoor average velocity for most rooms, and in turn increases the PMVnv value in both the seated and standing positions, it does not change the indoor thermal comfort level. However, the presence of a balcony improves comfort by increasing the uniformity of indoor air distribution. PMVnv is also shown to be less sensitive to ...
22 citations
TL;DR: In this article, the authors demonstrate a methodology for generating wind data on an hourly time grid from a consideration of the potential evapotranspiration reported by the UKCP09 weather generator and information related to the correlation between observed wind speed, direction and time of year.
Abstract: Pseudo weather data with a high temporal resolution are of use in many fields including the modelling of agricultural systems, the placement of wind turbines and building thermal simulations. With the publication of the 2009 UK Climate Projections (UKCP09) such data can be created for future years and for various predictions of climate change. Unfortunately such — UKCP09 — data does not include information about wind speed or direction due to a lack of robustness. Here we demonstrate a methodology for generating such wind data on an hourly time grid from a consideration of the potential evapotranspiration reported by the UKCP09 weather generator and information related to the correlation between observed wind speed, direction and time of year. We find our pseudo wind data is consistent with the historic observed wind. Furthermore, when used within a dynamic thermal simulation of a building, the use of such pseudo wind data generates a consistent internal environment in terms of ventilation rates, temperat...
TL;DR: In this article, the authors evaluate the performance of micro wind turbines in a built-up environment and present the basic background theory for horizontal axis micro wind turbine and the variation of coefficient of performance with wind speed.
Abstract: The aim of this article is to evaluate the performance of micro wind turbines in a built-up environment. For this purpose, five independent micro wind turbine systems, consisting of two distinctly different models, were tested and evaluated under real life conditions over a period of 12 months. This article provides an overview of the experimental set-up used to test the two different micro wind turbines and then goes on to present the basic background theory for horizontal axis micro wind turbines and the variation of coefficient of performance with wind speed. The wind potentials at the test site were assessed to determine the theoretical outputs of the turbines which were compared with the measured outputs over a year. The measured outputs were disappointingly low. One reason for this is turbulence, for which directional turbulence (lateral turbulence) has been shown to be a key indicator, better than the standard wind speed (longitudinal) turbulence. Another factor is the inverter efficiency and power...
TL;DR: In this paper, the UKCP09 grid containing Bracknell and Edinburgh was used to evaluate the change in the diffuse fraction of global irradiation in the 2080 High Emission data set.
Abstract: the UKCP09 grid containing Bracknell the 2080 High Emission scenario data gives an average value of 1002 Wh/m 2 , an increase of 23%. The same trend occurs for Edinburgh, (a present value of 789 Wh/m 2 and the predicted value of 948 Wh/m 2 , an increase of 20%). Note that compounded with presently found increase of 4–58C increase for the above locations, the substantial increase in irradiation will have a much more pronounced increase in the cooling load of buildings. An evaluation of the change in the character of solar radiation was also undertaken. This was done by noting the change in the diffuse fraction of global irradiation. For Bracknell and Edinburgh historic data and UKCP09 data 2080 High Emission data set show a drastic
TL;DR: In this article, the authors present the test and evaluation of energy saving potentials of complex building central chilling systems using GA, based on a simulated virtual system representing the actual complex central chilling system in a super high-rise building in Hong Kong.
Abstract: This article presents the test and evaluation of energy saving potentials of complex building central chilling systems using genetic algorithm (GA). The evaluation was conducted based on a simulated virtual system representing the actual complex central chilling system in a super high-rise building in Hong Kong. GA was used as the optimisation tool to search for globally optimal control settings. The simulated virtual system was used as the test platform and acted as the performance predictor in estimating the overall system performance and responses to the changes of control settings. The test results show that about 4.54—5.06% daily energy in the system studied can be saved by using optimal control settings, as compared to that using the conventional control settings. The results also show that the evaluation process by using the simulated virtual system and the GA optimiser is time costly due to strong dynamic effects of the simulated virtual system and the optimisation principle of GA.Practical applic...
TL;DR: In this paper, the authors examined the effects of increased external temperature on the size of the central air conditioning and heating plant for an example building and found that for each 18C rise in external temperatures, the peak cooling load increases approximately by 10%, the chiller power by 14% and fan power for distribution by 30-50% These are relatively large increases in power needed to counteract rising external temperature.
Abstract: Good building design aims to balance providing a comfortable internal environment for as much of the time as possible within a variety of constraints An important factor is the expected weather, but in a changing climate this poses additional challenges to engineers and architects This paper examines the effects of increased external temperature on the size of the central air conditioning and heating plant for an example building It is found that for each 18C rise in external temperatures, the peak cooling load increases approximately by 10%, the chiller power by 14% and fan power for distribution by 30–50% These are relatively large increases in power needed to counteract rising external temperature and the paper considers the choice of risk level for sizing building plant From HadRM3 data, the future frequency distribution of higher external temperatures is examined to evaluate the effects on plant size of designing to a fixed percentile of risk Projected changes in absolute humidity are also discussed Practical applications: Climate change is an important topic for building services engineers, resulting in the UK in the new, performance-based Building Regulations Part L New, future weather data will also become available with different climate change scenarios This paper examines the implications of both climate change and the risk level on the peak load for natural ventilation or air conditioning and heating that is used in the design of systems
TL;DR: In this paper, the authors present a decision support framework and software platform for an integrated assessment of options for sustainable management of urban pollution, which involves three steps: mapping the flow of pollutants associated with human activities in the urban environment; modelling the fate and transport of pollutants; and quantifying the environmental, health and socioeconomic impacts.
Abstract: This paper presents a new decision-support framework and software platform for an integrated assessment of options for sustainable management of urban pollution. The framework involves three steps: (1) mapping the flow of pollutants associated with human activities in the urban environment; (2) modelling the fate and transport of pollutants; and (3) quantifying the environmental, health and socio-economic impacts of urban pollution. It comprises a suite of different models and tools to support sustainability appraisals including life cycle assessment, substance flow analysis, source and pollutants characterisation, pollutant fate and transport modelling, health impact analysis, ecological impact assessment, and multi-criteria decision analysis. The framework can be used at different levels, from simple screening studies to more detailed assessments. The paper describes the decision-support framework and outlines several case studies to demonstrate its application. The software tool is available free of ch...
TL;DR: In this article, the authors explored the differences between traditional and modern patterns of passenger demand in office buildings and explored the significance of these differences on lift system design, and applied the traffic data in this paper will result in a more accurate prediction of a lift system's p...
Abstract: The number of passengers wanting to use lifts to travel to and from the lobby and between floors in a building has a significant effect on the quality of lift service experienced by each passenger. The traditional assumptions of lift passenger demand in office buildings are compared to measurements taken in modern buildings. The differences between traditional and modern patterns of passenger demand in office buildings are discussed. The significance of these differences on lift system design is explored. In office buildings surveyed, the daily pattern of passenger demand repeats itself with a high degree of consistency; buildings can be described as having their own demand ‘signatures’.Practical applications: Designing lift systems based on modern traffic patterns and traffic levels will result in systems with characteristics that are different from those designed using traditional traffic expectations. Applying the traffic data in this paper will result in a more accurate prediction of a lift system’s p...
TL;DR: In this paper, the terminal velocity at discharging drainage stack is a crucial issue as it provides the permitted permitted velocity for building drainage network in each developed city all over the world.
Abstract: A building drainage network is an essential provision of each developed city all over the world. The terminal velocity at discharging drainage stack is a crucial issue as it provides the permitted ...
TL;DR: In this paper, a robust model predictive control (RMPC) strategy was developed for CAV air-conditioning systems, which adopted two uncertain first-order plus time-delay models to describe the dynamics of the local processes and used a linear matrix inequality (LMI)-based optimisation technique to optimise the control law.
Abstract: Constant-air-volume (CAV) air-conditioning systems consist mainly of two local processes: an air-handling process and a room temperature process. A robust model predictive control (RMPC) strategy was developed for CAV air-conditioning systems, which adopted two uncertain first-order plus time-delay models to describe the dynamics of the local processes and used a linear matrix inequality (LMI)-based optimisation technique to optimise the control law. This paper develops a new control design, which reformulates the prediction models by shifting the uncertainties of the first model into the second one, and then uses the reformulated prediction models in the RMPC strategy. This paper will show that compared with the original design, the new control design can enhance the feasibility of the optimisation of control law, reduce the computational burden of the optimisation and also remove the requirement of a sensor for supply air temperature in the original design.Practical applications: The new design method i...
TL;DR: In this article, a new model has been proposed by Campbell and MacLeod to investigate the causative factors of airflow entrainment in building drainage-waste-ventilation (DWV) systems.
Abstract: Previous research into the hydraulic and pneumatic conditions in the pipework associated with building drainage waste and ventilation (DWV) systems has been interpreted as suggesting that the flow regime within the vertical stack consists of an annular water flow entraining a central air core with an associated pressure drop. However, previous evidence had suggested that a significant proportion of the water was found in the air core by Pink [A study of the effect of stack length on airflow in drainage stacks. BRE Current Paper, 1973; 38/73] and Wyly and Eaton [1961. Capacity of stacks in sanitary drainage systems for buildings. U.S. Department of Commerce, National Bureau of Standards, Monograph 3]. A new model has recently been proposed by Campbell and MacLeod [Investigation of the causative factors of airflow entrainment in building drainage-waste-ventilation (DWV) systems. Building Services Engineering Research Technology 1999; 20(3): 99—104] which suggests that the airflow entrainment is due to the d...
TL;DR: In this article, the effect of heat pipe heat exchanger on the heat recovery was studied in the tropics and the relevant empirical equations were then employed for the hour-by-hour prediction of the energy recovery by the heat pipe Heat exchanger for the whole year.
Abstract: The effect of heat pipe heat exchanger on the heat recovery was studied in the tropics. The performance of the heat exchanger was monitored during the one week of operation (168 h) to find out the performance characteristic curves. Three coil face velocities namely, 2, 2.2 and 2.5 m/s were tested and the temperature of return air was controlled at 24°C. The relevant empirical equations were then employed for the hour-by-hour prediction of the energy recovery by the heat pipe heat exchanger for the whole year. The impact of inside design temperature on the heat recovery by the heat exchanger was also studied. The thermal performance of the heat pipe heat exchanger was simulated based on the effectiveness-NTU method and the theoretical values were compared with the experimental data.Practical application: Performance improvement of the heating, ventilating and air conditioning systems is a challenge to the designers. The results obtained from this research work could serve as a practical guide for engineers...
TL;DR: In this paper, a research study was conducted to revise the heating degree days (HDDs) for main cities of South Korea, and the results showed that higher temperature trends due to global warming witnessed over the past decade in general decreased the HDDs.
Abstract: Because of the rapid rise in ambient temperatures in urban cities due to global warming, this research study was conducted to revise the heating degree days (HDDs) for main cities of South Korea. Current HDDs used in the design of heating systems were established some 30 years ago. Therefore, there is a need to revisit and revise the HDDs used in Korea. The HDDs were computed at five different indoor set-point and unloaded temperatures. The validity of the methodology used for computing HDDs was ascertained by comparing the calculated HDDs with the published values. The impact of the length of time on total annual HDDs was examined. The results show that higher temperature trends due to global warming witnessed over the past decade in general decreased the HDDs. The impact was higher for warmer climate cities than the cold regions. The revised annual HDDs for 15 major cities of South Korea are presented in this paper.Practical applications: The HDDs corrected for global warming effects for 15 major cities...
TL;DR: In this article, the authors presented a novel technological approach to achieve substantial savings in energy and water in residential developments; as well it can be used as a tool for billing, and consumption planning.
Abstract: Savings in energy and water consumption represents one of the most important challenges for governments around the world today. Residential developments in Mexico offer a feasible way for low-income families in populated cities to acquire a house. This paper presents a novel technological approach to achieve substantial savings in energy and water in residential developments; as well it can be used as a tool for billing, and consumption planning. The system was tested in the municipality of Tecamac during the warmest months of the year in Mexico. The following results were recorded: 13.43% of savings in power consumption, 10.18% related to the conservation of water and 9.13% less gas was used.Practical applications: Significant savings related to energy used and water conserved, are possible when networked technological systems such as the one proposed herein are installed either when the house is being built or can also be implemented in existing houses. Indirect benefits are present as well as tax reduc...