• Energy Research

Based on an unperturbed airflow assumption and using a set of validated modelling methods, a series of activities were carried out to optimise an aerodynamic design of a small wind turbine for a built up area, where wind is significantly weaker and more turbulent than those open sites preferable for wind farms. These activities includes design of the blades using a FORTRAN code; design of the nose cones and nacelles, which then constituted the rotor along with the blades; optimisation of the rotor designs in the virtual wind tunnel developed in the first part of the study; and finally, estimation of the annual power output of this wind turbine calculated using hourly wind data of a real Scottish Weather Station. The predicted annual output of the finalised rotor was then compared with other commercial turbines and result was rather competitive.

Abstract An experimental study was performed on a full-scale DAWT to understand its response behaviour to changes in wind speed fluctuations. A novel diffuser was designed from the results of previous numerical studies and was manufactured using lightweight materials. The resultant DAWT was made portable and tested in three wind directions. Wind speeds, wind directions and output power was recorded from both the bare wind turbine i.e. before it was applied with the diffuser and then the resultant DAWT. From experimental testing of the DAWT, wind speeds to the rotor were increased by 136% from 1.02 m/s to 2.41 m/s. The augmentation ratio was evaluated at 8.32 and the DAWT exhibited better responsive behaviour than the bare wind turbine in terms of matching the expected output power profile and a smaller response time.

Since the energy crisis in the 1960s, crucial research and activities were spurred to improve energy efficiency and decrease environmental pollution. To deal with the various problems the construction industry are facing, the concept of green buildings (GBs) has been gradually shaped and put forward all over the world, and green building rating systems (GBRSs) have been developed. The concept of GBs covers a wide range of elements, and its definition is constantly updated as the construction industry develops. This paper compares the development of backgrounds and statuses of green building development in various countries. It also presents an overview of the green building development situation within these countries, summarizing two influences for GB development: one external and the other internal. External factors include GB development policy support, economic benefits, and certification schemes. Internal factors are the development and application of GB technology, the level of building management, and how users interact with the GB technology. Currently, 49 worldwide green building standards and application have been sorted out, including 18 standard expert appraisal systems. Moreover, it discusses the research results and lessons learned from green building projects in different countries and summarizes their achievements and challenges. To correctly understand and use green building technology, it is essential to improve the policy and incentive system, improve the professional quality and technical ability of employees and accredited consultants, constantly develop and update the evaluation system, strengthen technological innovation, and integrate design and management. This paper aims to draw a clear roadmap for national standard development, policy formulation, and construction design companies, provide solutions to remove the obstacles, and suggest research direction for future studies.

Abstract The indoor environment quality in large glazed space such as airport terminals affects its users in many ways. The indoor environment quality assessment of such a building was typically conducted objective measurement using measurement and subjective assessment using questionnaire survey. However, limited resources and measurement period imply that would be incomplete and cannot provide accurate results. Computer modelling is thus an additional tool in the integrative approach for indoor environment quality assessment and analysis to improve its comfort and energy performance. Field measurement on the objective variables defined the environment quality and energy consumption, as well as questionnaire survey on the subjective judgment defined the indoor comfort. While the computer modelling was assessed across the air temperature, indoor glazed roof surface temperatures, mean radiant temperatures, operative temperatures and illuminance, to examine the building energy performance across the annual cooling load in 2010. The inner surface temperature over glazed roof were recorded as 56 °C due to high level solar penetration, even when the indoor air temperatures over the floor level remain stable within the standard comfort zone. This rose the mean radiant temperature and was considered as main cause for indoor discomfort revealed by the survey. The survey found the employees to be slightly uncomfortable and dissatisfied, particularly in summer. The total energy consumption in 2010 was very high compared against the energy benchmarking. This study confirms that the large proportion of glazed roof is the cause for both overheating and thermal discomfort even with excessive use of the cooling system. In addition, recommendation was made to improve the thermal comfort condition in the large glazed air-conditioned terminal.

Abstract In response to the non-trivial problem of overheating in glass roofed buildings in low latitudes a study was undertaken to reduce discomfort and high energy consumption in a large atrium building in China. This paper reports on the development of a shading system designed for that building as a remedial solution to reduce temperatures while maintaining adequate levels of natural lighting in the atrium spaces of a large multifunctional commercial building. The effects of the shading system on both the physical indoor environment and its economic implications were analysed using implemented models. Calibrated with the data measured in the building during the hottest season, summer, the models were used to test both thermal and lighting performance of two shading arrangements: high and low level blinds in both open and covered modes on typical overcast days and clear days in summer and winter respectively. Also tested were two types of fabric used for the blinds. The performance of these tested cases was assessed for solar gain, cooling loads, internal surface temperatures, air temperatures and operative temperatures of both ground floor and surrounding walkways on various levels within the atrium, the major circulation areas. The results reveal that the high level shading, with blinds fixed close to the glazed roof are generally less effective in the provision of thermal and lighting conditions of the atrium, than the low level shading, where blinds are fixed 3–5 m below the glazed roof to form a ventilated void. The financial benefits of these remedial solutions were also assessed using standard economic analysis methods to provide recommendations on their costs and payback periods.

Eco-village development has been considered by the Chinese central government as part of its rural revitalisation campaign and it is seen as a crucial/main solution to the increasingly serious rural issues caused by urban–rural inequality. A significant number of eco-villages are being or will be developed with government leadership and support under the guidance of a corresponding assessment. However, the latest Chinese eco-village assessment, the Evaluation for the Construction of Beautiful Villages (ECBV), has been found to have limitations related to the assessment process, method, and indicators, meaning that it cannot be used to perform a balanced evaluation of the social, economic, and environmental aspects of an eco-village. As assessing an eco-village is as essential as building it, it has become necessary to balance the criteria and improve the ECBV assessment so that it can review existing achievements, guide further development, and ensure better outcomes. Thus, this paper aims to: (1) identify the limitations of ECBV through a case study of a carefully selected Chinese eco-village, Zhenghu Village, by repeating the assessment process and analysing the assessment results, and (2) propose three possible solutions to improve the assessment by applying a revised ECBV assessment, the components of which are adopted and revised from an internationally recognised sustainability assessment, the Sustainable Development Indicators (SDIs). The results of the case study confirm the limitations of the ECBV assessment. Besides, the research outcomes of these three possible solutions can improve ECBV assessment and also provide ideas for the improvement of other existing assessment methods. Moreover, other developing countries may apply the research process and method introduced in this paper to formulate or improve their own eco-village assessments.

Abstract A Solar Wall Heating (SWH) system was developed to provide low cost space heating in traditional solid stone-walled tenement buildings in Scotland. The SWH system uses the internal solid walls to store the solar heat collected during the day and heat the bedrooms during the night. A physical laboratory model with attached solar hot water system and a computational model of it were developed to investigate the dynamic performance of the system in use and test the cost benefits of iterations of its modes of use. The temperatures throughout the wall structure were measured under the variant solar input of a 24-h cycle. An unsteady state CFD model was developed and validated using the measured data and setup to test a number of key variables of the solar wall heating system in use. These included optimisation control strategies and maximisation strategies for the collection and storage of solar heat under various conditions. This paper presents the modelled results of the solar thermal storage and optimisation system and strategies for internal solid stone walls in a typical Scottish tenement flat in the Scottish climate. In addition the study analysed the solar availability, heating demand and domestic water supply of two typical dwellings based on two reliable methods: (a) a purpose built dynamic thermal model and (b) data collected in previous studies. The study demonstrated that the solar collection of current solar hot water systems can be improved upon so that, even in Scotland, more solar power can be harvested to contribute not only to domestic hot water, but also domestic space heating, particularly in buildings occupied over 24 h with heavy thermal mass. The cost analysis of the system in use suggested a 16 year payback period for such a system for a tenement flat.

Abstract Using both measured and modelling data, the hygrothermal environment in a national gallery was examined to envisage the buildings response to weather conditions, occupancy and HVAC operations. The measured data were acquired from the BMS system and purposely fitted monitoring instruments. The data was also used to validate a specially developed dynamic thermal model, which was then used in a series of simulations in a parametric study. The simulations ran under nine designed cases to test a number of low energy solutions proposed in a gallery renovation project, namely upgrading skylights, adding roof insulation, and applying an adaptable environmental control strategy. Through this systematic analysis and quantitative comparisons this study intends to provide reliable information for decision making for the renovation work to ensure an optimal solution and best results. This study was benefited by a close collaboration between the physicist, computer modeller, building manager and gallery conservationist.