Specialist Research Areas & Projects
Alternative Energy Resources and Renewable Energy
Building Acoustics and Vibration
Building Automation and Intelligent Building
Building Environmental Performance
Building Operation and Maintenance
Electrical Installations and Systems
Heating, Ventilation, Air Conditioning and Energy Studies
Alternative Energy Resources and Renewable Energy
Researchers : Dr H X Yang (leader), Dr K T Chan, Dr S M Deng, Prof Francis W H Yik
Collaborators : Dr Y Q Ni, Civil and Structural Engineering Department, HKPolyU
Research Fellow : Prof S J You
Research Students : Miss L Lu, Mr G Gang, Mr Y Y Fung, Mr K Tsang
Research Assistant : Mr D An, Mr C Lou, Dr C Ren, Dr Z Zhu
The research and consultancy activities in the Renewable Energy Research Group (RERG) include research and consultancy in building-integrated photovoltaic applications (BIPV), wind power generation, hybrid solar-wind power, solar thermal application, solar cooling technology and building energy conservation. We have a team of renewable energy R&D specialists in system simulation, system design, development of control devices and data collection/analysis. We have completed a number of high-profile research projects and consultancy projects in Hong Kong, Macao and Guangdong. Funded by the Industrial Support Fund, the first BIPV project in Hong Kong was set up in 1999 on the campus of The Hong Kong Polytechnic University. We have done a number of experiments for different PV systems. The project has attracted a lot of visitors from different sectors. Since then, a number of BIPV projects have been developed in Hong Kong. Besides, we developed the first solar street lighting project in 2000 and the first commercial grid-connected PV-Roof project in 2002 for Kadoorie Farm and Botanic Garden. So far, we have completed more than 5 research projects for the Research Grant Council, the University and other organizations, and 8 consultancy projects for local industry. We have set up the unique 2¡Ñ2m Solar Simulator Lab in the University. We anticipate more collaborations with local industry, the industry in Chinese mainland and overseas counterpart in the future.
Research Projects
Photovoltaic integration in buildings for electricity generation in Hong Kong
(HK$1,710,000, Innovative Technology Scheme)
This project was formerly started on 1st August 1997 and ended on 31
April 2000. All the work defined in the original proposal has been completed. Some work is even out of the scale of work proposed. The successful demonstration of the project has attracted a lot of people from various areas including Government
officials, businessmen, industrialist, environmentalists, researchers and students. Research results from the simulation/experimental work are being and will be
used by local industry for building-integrated photovoltaic applications for
solar energy power generation in Hong Kong.
The main deliverables include the demonstration/experimental BIPV project and computer simulation and experimental monitoring results in terms of technical, operational, environmental and economical issues. The permitting/legal and potentiality issues have also been investigated. An experimental test has been done on grid-connected photovoltaic system. The performance data of the BIPV systems will be used as design guidelines for new BIPV developments.
The project benefit the local industry for developing related industrial products. In fact, a number of local manufacture companies are developing such products, e.g. PV curtain wall, PV-roof cladding, PV system controllers and remote PV systems. They are very interested in R&D collaboration and investing in solar energy research and developemnt. A number of PV projects are now being developed or initiated in Hong Kong due to the work in this project. Solar energy for electricity generation is now a big business in the world and a new business in Hong Kong. This is a very sucessful project with good results.
Energy performance evaluation of advanced-window frame systems
(HK$457,817, Research Grants Council)
The goal of this work is to investigate the influence of advanced-window frames on window's
energy performance and to develop the energy efficiency criteria for selecting
windows for the climates in Hong Kong and Mainland
For cooling-dominated climate in Hong Kong and Southern China, and heating-dominated climate in Northern China, U-value and solar radiation transmission
through windows play important roles in heating and cooling energy consumption.
How to select approximate windows for buildings remains a problem. As
a result, no guidelines for local architects and building services engineers
to choose appropriate windows for different types of buildings for energy
conservation. This project intends to evaluate the existing window rating methods in developed
countries for proposing a rating system based on the theoretical and experimental investigations for window frame
systems. The results can be used for developing a design
guideline for local engineers and built industry. The research will also benefit the local manufacturing industry for development
of advanced window systems.
Study on hybrid solar-wind power generation for renewable energy applications in Hong Kong
(HK$170,000, The Hong Kong Polytechnic University)
In recent years, renewable energy applications
in Hong Kong
and the adjacent areas have developed rapidly.
A number of high-profile solar energy projects have been or are being completed
in Hong Kong. It is found that solar energy and wind energy for power generation
are regarded as the most viable renewable energy sources. The combination of these two renewable energy systems, i.e. hybrid solar-wind systems, can provide
reliable and continuous power supply in an area. This project aims to investigate the hybrid solar-wind energy system technology and its application for the Hong Kong weather and economic conditions. A simulation model for analyzing the probability and reliability of hybrid photovoltaic-wind power generation
systems will be developed. An analysis of the complementary characteristics between solar irradiance
and wind power will be made. An optimization procedure and design guideline
of a hybrid photovoltaic wind energy system will be proposed for local engineers
and energy industry. A small-size hybrid solar-wind energy system will
be set up for simulation validation and demonstration purposes. Based on the outputs from the simulation and experiments, the potential and feasibility of the hybrid solar-wind technology application
in Hong Kong will be assessed and predicted. An
overall assessment of the value of the technology will be made for its application
in Hong Kong.
The technical, economic and management issues related to the application of this new technology in Hong Kong will aslo be investigated. The successful realization of the project will contribute to the Government's targets for a clean
environment and high-tech industry in Hong Kong.
Development of an innovative building-integrated photovoltaic cladding technology
(HK$500,000, The Hong Kong Polytechnic University)
Application of photovoltaics in buildings (or building-integrated photovoltaics,
BIPV) develops rapidly in Hong Kong and the world in recent years, but the cost is till high compared with traditional fossil fuel power generation.
How to reduce the cost is always the priority. This project is proposed to investigate an innovative
cladding techniquc, i.e. the direct-integrated photovoltaic technology (DIPV) for combing photovoltaic
modules with building cladding so that the total cost is reduced and the aplication of BIPV could be made feasible. The thermal and structural perforamnce of the new BIPV cladding systems will be investigated by the solar energy research expertise in the BSE Department and the strucural engineering expertise in the Civil and Structural Department. The main objectives are as follows:
¡P To investigate the electrical and thermal effects of the DIPV roof elements on building¡¦s energy and environmental performance;
¡P To study the optimum design of the DIPV technology through numerical simulation;
¡P To simulate and test the structural strength of the developed DIPV systems to prevent damage from typhoons and to improve their structural design. A wind tunnel test and other structure lab tests will be needed;
¡P To develop an optimization procedure and guideline for using this technology;
¡P To assess the potential of this renewable energy technology application in Hong Kong;
¡P To demonstrate this technology for local industry by setting up an experimental system;
¡P To develop an innovative product or more products of this innovative technology for commercialisation.
Energy performance test of the indirect evaporative heat exchanger at Kowloon Park
(HK$50,000, The Four Gay Engineering Company)
This project was completed in March 2003. The following conclusions can be drawn from the study:
¡P This indirective evaporative heat exchanger or indirective evaporative cooling system (IECS) is suitable for Hong Kong¡¦s weather conditions with hot and humid climate. The latend enegy recovery due to evporation of condensate water is significant for the total energy recovery;
¡P The energy performance of the IECS is very good, especially for peak cooling load reduction. The IECS is highly reccommended for application in new central air-conditioning systems with new chiller plants or exiting air-conditioning systems with renovated chiller plant for reducing the initial investment of the new chillers;
¡P If the IECS is added to an existing A/C system without changing its chiller, the payback period ranges from 3-6 years depending on the actual equipment¡¦s initial cost. However, the payback period could be droped to about 2-4 years if a larger module is used (this tested module is a very small module of the module series provided by Four Gay Engineering Co. Ltd.);
¡P The operation and maintenance of the system is easy and reliable;
¡P Environmental factors have not been taken into account in the above economical analysis. If environmental benefits are considered, the payback period will be shorter. In fact, the energy conservation technology also reduces fossil fuel consumption so that environment is protected. Pollution from burning fossil fuels has caused a lot of serious environmental problems, e.g. particle emission and global warming gas generation.
This project is continued with more detailed theoretical investigation in simulation and simulation validation funded by the Department (HK$280,000)
Numerical investigation of natural convection in inclined channels
(HK$170,000, The Hong Kong Polytechnic University)
Natural convection of air in inclined channels including horizontal and vertical channels are widely available in various solar energy applications, such as solar collectors, double glazed semi-transparent PV wondows, ventilated PV roofs and PV walls, and TIM-walls. The heat and mass transfer, and the naturnal convection issues have been investigated by the research group. The numerical study of heat transfer in a ventilated photovoltaic (PV) panel is carried out for its effect on the energy performance of PV modules and cooling load of buildings. The buoyancy induced thermal fluid instability between two parallel horizontal plates has been investigated numerically by solving the governing equations of the base and perturbation fields using a fractional algorithm. The super-critical secondary flow properties of natural convection in an inclined channel (NCIC) have been explored numerically by virtue of Boussinesq type Navier- Stokes equations. The simulation results have been used in the development of optimized solar energy systems in which the concept of natural ventilation is incorporated.
Solar street lighting and solar garden lighting
(HK$200,000, British Council and Kadoorie Farm)
Remote solar lighting represents one of the major uses of solar energy applications for power generation. The detailed simulation model and advanced solar lighting controllers are developed by this project jointly funded by British Council and Kadoorie Farm. The optimum sizing problem has been solved through the simulation. Different adjustment methods have been investigated for improving the energy performance of solar lighting systems. The deliverables have been used in the solar street lighting and garden lighting systems along the main street in Kadoorie Farm, the first street lighted by solar energy resource in Hong Kong. Collaboration with local industry is now going well to develop more advanced solar lighting and garden lighting systems.
The solar street lighting and garden lighting systems in Kadoorie Farm
Building Acoustics and Vibration
Researchers : Dr S K Tang (leader), Dr C M Mak, Dr Daniel W T Chan
Collaborators : Prof J Tian, Institute of Acoustics, Chinese Academy of Sciences, P.R.China
Dr N Peake, DAMTP, Cambridge
University,
Dr J
Yang, Division of Information Engineering, School of Electrical & Electronic
Engineering, Nanyang Technological University,
Research Students : Mr Elvis C K Lau, Mr Eddie S K Lau, Mr Stephen C H Ng,
Mr B R Vijaya Raghava Raju
Research Assistant : Mr Louis W L Chan
This research team focuses on advancing technology in enhancing the acoustic and vibration control in the built environment. Topics concerned include the application of active noise control, development of assessment methodology, noise prediction and control in flow ducts, air-borne and structure-borne sound transmission within residential estates and within buildings, acoustical environment performance, mobility studies, speech intelligibility in schools, architectural acoustics and signal diagnostics.
Efforts have also been made on the development of commercial usable products. A low pressure loss broadband compact duct flow silencer is in the design stage. Also, research works concerning vibration transmission within buildings will lead to the development of a realistic statistical energy model for use in new building design. In addition, it is planned to develop an active controller for transient noises.
The research team also gives advices to the industry in forms of brief communications and/or PolyU consultancy projects. The topics / issues cover nearly all branches of applied acoustics and are not restricted to those described above.
Research Projects :
Active control of sound transmission through panel structures
(HK$474,000, Research Grants Council)
Sound transmission through doors, windows
or other panel structures has long been a problem in building services noise
control. Daily life examples of it include the transmission of traffic
and aircraft noise into living and sleeping rooms and the noise that goes
into offices from air conditioning plant. While the high frequency component
of the noise can be attenuated by materials like carpet, fibre
glass and furniture, the low frequency component remains hard to attenuate
due to the nature of the mentioned materials. It has been shown by other
researchers that sound can be cancelled by another sound with the right phase
and amplitude in an air duct. The cancellation sound characteristics
are changed by a specially designed controller to adapt to the change in sound
field. This method, which is known as active noise control, is proved
to be very efficient in attenuating low frequency noise. In the present
project, this idea is extended to three dimensional space.
To be more related to daily life, the transmission of low frequency noise
through plate structures (to simulate windows or doors) into an enclosure
(and thus, a living or sleeping room) is studied and its active control investigated
both experimentally and theoretically. It is hoped that an appropriate
control system can be derived.
Establishment of noise level distributions and development of a noise criterion in building services engineering
(HK$239,980, The Hong Kong Polytechnic University)
The distributions of noise levels in the community, may it come from transportation or mechanical services, usually determines the setting up / selection of noise criteria and the noise mitigation methods to be employed. An understanding of them will result in a simpler noise measurement procedure and specification for acoustical environment. In addition, such understanding enables prediction of acoustical parameters without measurements. There has been research elsewhere studying the statistical distribution of traffic noise level. A recent investigation by the author has shown that the noise level inside office buildings has a particular probability density distribution.
The present study is an attempt to find out the distributions of community noise levels, which are mostly unknown to the knowledge of the author, and to the setting up of a suitable / unified noise criterion for general use as this topic remains controversial, despite the continuous effort of active researchers.
An investigation on the self-noise generation of the dissipative silencer and its control
(HK$985,817, Research Grants Council)
This research proposal deals with a flow-induced noise problem that occurs in the conventional silencers in the air conditioning systems of modern buildings. Both theoretical and experimental investigations on its generation mechanisms and control method are included. In a modern building, the air conditioning system provides thermal comfort control in its interior but it also generates noise. This noise can propagate to the building interior through the ductworks and can go to the surrounding of the building causing nuisance to its own users and its neighbours. Dissipative silencers are commonly used to attenuate this kind of noise. This kind of dissipative silencer attenuates noise by the viscous actions in the porous material lining (usually made of fibreglass) inside the silencer. Effective range of noise control is limited to the middle to high frequency. Splitters made of porous materials are included in the silencers to increase their sound attenuation capacity. However, the restriction on the turbulent flow due to the silencer installation and the splitters create flow instability problem, introducing additional vorticity into the flow which interacts with the solid boundaries no matter they are rigid or porous and eventually produces noise. The vorticity within the original turbulent flow will also radiate sound as its motions are restricted by the configuration of the silencer. Though the level of this self-noise may not be high enough to override the overall noise attenuation provided by the porous materials, this self-noise does reduce the performance of the silencer. However, if it is of low frequency, there will be a risk of low frequency noise amplification by the silencer. The results of the present proposed research can provide a reliable physical model for the generation mechanism of this self-noise and thus its prediction. With a clearer understanding on its generation mechanism, a control method can be derived and tested in the laboratory.
Generalization of noise level distribution theory for improved noise assessment, prediction and control in the built environment
(HK$718,404, Research Grants Council)
Noise pollution has become an important issue
in every metropolis. The sources of noise include at least the
ground transportation, aircraft, building services, industrial and human activities.
For Hong Kong,
which is a hilly, congested but highly dynamic city, this problem has become
acute with the continuously growing population. Though the economy has
not grown very fast in the past few years, the construction of large-scale
infra-structures will eventually spread noise pollution issue from the urban
areas to the sub-urban and rural areas. Every new establishment or re-development
therefore requires serious noise pollution assessment before construction
can be started. A reliable scheme for noise prediction is of prime importance
for noise control within the existing and future environment. However,
despite the effort of many researchers, such a prediction scheme does not
yet exist. There are schemes which enable the estimation of noise level
under a given traffic condition also but they are non-general and appear to
be case/city dependent. They are to some extent uncorrelated such that
ambiguous results can be obtained.
Experience and the results of the author's research, which will be discussed later in this proposal, suggest statistically that environmental noise, no matter it is outdoor or indoor, is not as random as the current researchers believe. It is highly probable that a generalized form of environmental noise level distribution does exist. This project is specifically intended to attempt to determine the form of such a distribution and contribute to the development of a theory for environmental noise. The outcome will contribute to the development of a reliable and informative prediction scheme for noise environment and may also find applications in the field of applied statistics.
An investigation on the effectiveness of balconies as noise barriers
(HK$359,075.5, The
Hong Kong
Polytechnic University)
Balconies at building façades are believed to be able to provide screening for noise from ground sources. However, the multiple reflections by adjacent balconies and the reverberation inside a balcony have resulted in noise amplification instead of reduction, especially at the low frequency range where resonance is likely to occur. The project is set up to investigate the actual effectiveness of balconies as noise screening devices for residential buildings. Methods to improve the screening effects of balconies on building facades will also be explored. These methods include the alteration in balcony shapes and the use of new durable passive sound absorbers in the balconies. A model will be set up for reliable prediction of balcony insertion loss. The results of the present results will be feedback to the profession for the setting up of ¡§good practice¡¨.
Development of a low pressure loss broadband silencer
(HK$677,040, Research Grant Council)
This project is an attempt to develop a low static pressure loss broadband compact silencer for practical use in buildings. The low frequency noise from the air conditioning system has long been a problem in the building industry. This is of particular importance for a high-rise and congested city like Hong Kong. The conventional dissipative silencer is intrusive, resulting in a considerable static pressure drop across it and thus high fan power consumption is resulted. The performance of the dissipative silencer is also not satisfactory at low frequencies. The concept of the two-dimensional drum silencer has been tested successfully in our laboratory. However, the effect of flow and the issue of optimization have to be done before a real product can be produced for practical use.
An investigation on improved sound and vibration transmission prediction for high-rise buildings in Hong Kong
(HK$170,000, The Hong Kong Polytechnic University)
In this project, theoretical models will be developed to predict sound and vibration transmission between building components. This will build on existing models used for European style masonry buildings. These models will be validated with laboratory studies of transmission between individual components. These laboratory measurements will be supported by extensive site measurements. Special attention will be made to improve the sound transmission performance at low frequencies and in the development of experimental techniques for large-scale projects. The present project will provide a deeper understanding on the properties of buildings and will also allow noise control schemes to be developed in the future.
Investigation of regenerated noise in ventilation systems
(HK$139,000, The Hong Kong Polytechnic University)
There is increasing concern about the noise
generated by the interaction of air flow and duct elements in ventilation
systems. This type of noise is known as regenerated noise. The accurate prediction
and control of the regenerated noise in ventilation systems is of considerable
importance in engineering. Nevertheless, the existing design methods such
as ASHRAE Handbook and Part B12 of the CIBSE Guide for predicting regenerated
noise due to air duct elements are recognized as being inaccurate in practical
systems. This project builds upon the earlier work of the applicant on direct
predictions of regenerated noise from turbulent kinetic energy in the vicinity
of an isolated spoiler in air ducts using computer tools. The aim of this
study is to extend the earlier work of the applicant to the study of situations
involving two spoilers and to develop a generalized method of predicting regenerated
noise in ventilation systems.
Study of structure-borne sound due to HVAC equipment
(HK$200,000, The Hong Kong Polytechnic University)
There is increasing concern about the noise and vibrations generated by air-conditioning systems in buildings in Hong Kong. Although sound levels in occupied spaces in new buildings due to air-conditioning systems are nowadays calculated as a matter of routine, there are many hurdles in predicting structure-borne sound. Air-conditioning equipment such as air-cooled chillers are usually installed on the roofs of buildings. Although the ASHRAE handbook recommends that noise-sensitive area should not be near or adjacent to electrical and mechanical (E&M) plant rooms, it is unavoidable in Hong Kong to have noise-sensitive rooms such as a penthouse-type executive office just under the E&M floor. Force transmissibility is commonly adopted in building services engineering to choose vibration isolation. The problem that motivated this study is the occasional unsatisfactory performance of vibration isolators in building services engineering. This may be due to the over-simplification of the problem of vibration in the usual definition of un-damped force transmissibility commonly used in engineering practice. In addition, it is also due to the complexity of structure-borne sound problems. The aim of this work is to investigate the methods of measuring force and moment mobility and to study analytically the possibility of developing methods for selecting vibration isolators for HVAC equipment.
Study of interior sound fields using the finite element method
(HK$90,000, The Hong Kong Polytechnic University)
Despite the benefits of thermal comfort provided by rooftop equipment such as air-conditioning equipment, vibratory equipment can cause problems in an indoor acoustical environment. The building structure where the rooftop equipment is placed vibrates and emits sound into indoor space. Although considerable engineering work such as the installation of vibration isolators is employed, the amount of sound emitted by the structure of the building into the indoor space is still unclear. In order to reduce the interior noise levels at the design stage, it would be valuable if a computer-modelling technique could be employed to simulate the indoor sound fields caused by external vibratory forces imposed on the top of the room space. The aims of the study are therefore to model the interior sound fields due to vibratory rooftop equipment; and investigate the possibility of predicting and controlling the interior sound fields by a computer modelling technique.
Application and development of computer modelling techniques to the study of HVAC silencers
(HK$191,000 The Hong Kong Polytechnic University)
Concern has increasingly been expressed in Hong Kong over the quality of the indoor acoustical environment in office buildings. Noise from air-conditioning systems is usually one of the major sources of noise in offices. Various sources of noise are encountered in HVAC systems. Silencers are commonly used in a wide variety of applications. HVAC flow air ducts commonly make use of silencing elements to attenuate the noise levels carried by the air and radiated to the office environment. Restrictive environmental legislation, codes of practice and design guides for indoor environment require that such systems be designed with a high performance and reliability.
Various techniques are currently available for modelling and testing air duct silencers. Empirical, analytical and numerical techniques have been employed and have proven to be reliable under controlled conditions and for different applications and duct system configurations. For more complex geometries (larger attenuation values are required), numerical techniques such as the finite element method and the boundary element method are applied with advantage. The principal objectives of this research are: to model the silences in HVAC systems by computer simulation; and to analyse the performance of the HVAC silencers.
Building Automation and Intelligent Building
Researchers : Dr S W Wang (leader), Dr M L Chen, Dr S M Deng
Collaborator : Dr J N Cao, Department of Computer, The Hong Kong Polytechnic University
Prof A Dexter, Department of Engineering
Sciences, The University of Oxford,
Research Students : Mr Jet J T Cui, Miss J Y Qin, Miss Linda F Xiao, Mr X Xu
Research Associate : Dr Z M Jiang
Research Assistant : Mr S Lo, Mr Z Y Xu
The areas of expertise and strengths of this research group are related to the robust control, optimization and assessment strategies of building services system, fault detection and diagnosis strategies, dynamic simulation of building systems, building automation and intelligent building system technologies. This group is also active in the development of web-services for remote building monitoring and diagnosis. Training courses on intelligent building technology, building control and optimization have been offered to professionals in the industry.
An Intelligent Building Laboratory is established. It consists of two integrated intelligent building and building management systems, integrated BACnet controllers, an integrated LonWorks control networks, an integrated home automation system, building emulators, an IBMS integration and management software (IBmanager), teaching software packages (BMSonline and BACnetViewer), etc. The laboratory provides the test facilities for research and development on intelligent building system integration and BMS communication, advanced building system control, management and diagnosis, facilities management software development besides supporting teaching.
IB Manager Network
Research Projects
Sensor fault detection, diagnosis and evaluation of building management systems
(HK$405,000, Research Grants Council)
The objective of this project is to develop a suitable method and the strategies to detect faulty sensors, to diagnose (locate) the faulty sensors and to evaluate the magnitude of the sensor faults. The strategies are to be used in the advanced Building Management Systems to ensure and enhance that the monitoring and control of BMS and on computers to evaluate sensor faults using the data recorded in BMS commissioning stage to increase the efficiency and quality of BMS commissioning.
Fault validation and fault tolerant control of building automation systems
(HK$710,000, Research Grants Council)
In the building HVAC field, developments on fault detection and diagnosis have been focused on HVAC components and systems. However, the existence of monitoring and control faults in outdoor air ventilation control and air handling units of air-conditioning systems is a common problem for the application of BASs in Hong Kong as well as in other countries. As a consequence, faulty monitoring and controls result in poor indoor air quality and energy waste and affect the further development of BASs.
The objective of this project is to develop a strategy to detect/diagnose the faults (in flow, air temperature, and differential enthalpy and differential flow measurements) and correct or recover the measurements in the presence of bias or failure, and a relevant control strategy that can adapt itself to maintain acceptable control performance of Building Automation Systems in the presence of measurement faults.
Robust and optimal DDC control of outdoor air ventilation in buildings
(HK$470,000, Research Grants Council)
The objective of the project is to develop a robust ventilation control strategy that optimizes the ventilation management by taking into account both requirements for good indoor air quality and for minimizing the air conditioning loads and hence the energy cost. The demand controlled ventilation strategy detects the dynamic changes of the occupant load, and controls the outdoor ventilation airflow rate to follow these changes. The strategy improves robustness and accuracy of the ventilation control, with reduced sensitivity to CO2 and outdoor airflow measurement errors, in and between different modes of ventilation control.
Adaptive and optimal control building air-conditioning systems
(HK$240,000, The Hong Kong Polytechnic University)
The objective of the project is to develop
and evaluate the strategies and methods for on-line control optimization of
variable-speed seawater pumps, which is supported by real time parameter estimation
and on-line prediction of system performance based on Genetic Algorithm and
fuzzy-based supervision. On-line optimization is achieved by optimizing and
resetting the pressure setpoint of seawater supply
pressure.
This project includes the development and evaluation of the strategies for on-line identification of the essential parameters of indirect seawater cooled and direct seawater cooled chilling systems, to test and implement Genetic Algorithm in on-line parameter identification and on-line prediction of system performance, and to implement fuzzy-based strategies for supervision of the pressure setpoint reset control.
Development of an intelligent building platform integrating BMS and FMS on internet
(HK$200,000, The Hong Kong Polytechnic University)
In the recent years, there is a clear trend to adopt Internet/Intranet as the underlying infrastructure for intelligent building management. In this project, we aim at developing the framework and methods for integrating Building Management Systems (BMS) and Facilities Management Systems (FMS) using Internet and middleware. We will also develop techniques to support efficient remote access to the integrated system. Three main issues will be addressed:
• Integration of building control networks and Facilities Management via Internet;
• Development of middleware supporting convenient data exchange with client systems,
• Web-based remote access of BMS and database integration.
Fault diagnosis and sensor fault isolation of centralized chilling systems for intelligent management and robust control
(HK$200,000, The Hong Kong Polytechnic University)
Centralized building chilling systems are one of the major energy consumers. Building Management System has become an essential part of the system in the last two decades. The recent advances in network technology and the compatibility of BMS network protocols allows the Direct Digital Control (DDC) panels of individual chillers to be conveniently integrated into the BMS systems, allowing the BMS to have rich information including the internal component operational conditions of chillers and the chilling system.
However, nowadays, most Building Management Systems (BMS) installed in practical central chilling systems are not utilized sufficiently. The measurement uncertainties and errors, together with component faults, as well as the lack of diagnosis tools and software, result in unreliable monitoring, diagnosis and automatic control. In consequence, automatic controls of many chilling systems are not working properly and system/component degradations might be ignored for a long time.
The objective of this project is to develop methods/strategies for the detection and diagnosis of chilling plant degradations isolating the measurement errors, in order to achieve robust control, automatic commissioning and preventive maintenance. These methods/strategies will enhance the accuracy and robustness of monitoring, diagnosis and control, and therefore provide a means for improving building energy efficiency and intelligent control, benefiting the development of intelligent and sustainable buildings in Hong Kong.
Building Environmental Performance
Researchers : Prof Francis W H Yik, Dr C K Chau, Dr W L Lee,
Dr Daniel W T Chan, Dr J L Niu, Dr T M Chung, Dr S K Tang,
Dr H X Yang, Dr Horace K W Mui, Prof J Burnett
Collaborators
: Prof P Jones, The Welsh School of Architecture, University of Wales,
Dr Esmond Mok, Dr Lillian Pun, Mr Geofrey Shea of Land Surveying
and Infomatics Department, The Hong Kong Polytechnic University
Research Fellow : Prof M Bojic
Research Students : Miss Angela S H Chan, Mr T M Leung
Research Assistants :
The Department has made considerable progress in its research and development work in the area of building environmental performance in the past few years. Development of and major review on the different versions of Hong Kong Building Environmental Assessment Method (HK-BEAM) for new and existing office buildings and high-rise residential buildings has also been completed. A new and more comprehensive version of HK-BEAM for new and existing building developments was released in May 2003. The publicity of HK-BEAM has grown substantially in the past year reflecting greater awareness to Hong Kong¡¦s environment.
The Department is expanding the HK-BEAM scheme
into an assessment framework that would embrace all types of buildings.
In addition to the assessment schemes, the framework would include provision
of supporting information and analysis tools to allow wider dissemination
of the assessment scheme, the methods and techniques for evaluating the environmental
performance of buildings, and measures for achieving higher standards.
The Department is actively seeking collaboration with, and funding from, interested
parties to develop the scheme.
The continuous enhancement of HK-BEAM also spins off a variety of coordinated active research studies. These studies include energy efficiency of building services, thermal performance of building envelopes, wind environment around buildings, natural ventilation and daylight applications in residential buildings, indoor environmental conditions, thermal comfort, building acoustics, human factors, building econometrics and decision making processes, benchmarking building environmental performance, development of simulation programs for prediction of energy and environmental performance of buildings and plants, life cycle analysis and economic factors to be considered in building environmental assessments.
Advanced building technology in a dense urban environment (Building environmental performance)
(HK$5,801,178, The Hong Kong Polytechnic University)
The project focuses on three major tasks, namely design optimization of new high-rise residential building envelop, design optimization of new air-conditioned buildings and the heating, ventilation and air conditioning systems and the benchmarking of existing buildings. In the first task, effects of all environmental aspects, such as wind and rain, solar heat, noise and lighting, on the built environment are analyzed with theoretical, computational and experimental techniques. Physical models for design are reviewed and re-defined. The second task is the development of the design software HTB2/BECON. The third task focuses on benchmarking performance of buildings. This is done through extensive site surveys and the applications of econometrical methods. Outputs are consolidated in the Hong Kong Building Environmental Assessment Method (HK-BEAM).
Development of a computer simulation package for studies on the environmental performance of buildings in Hong Kong in estate or district-wide scales
(HK$500,000, The Hong Kong Polytechnic University)
The aim of the project is to develop a computer simulation package for use in studies on the environmental performance of a group of buildings, such as buildings within an estate or in a district. On the basis of a geographical database built from GIS data, the program will be able to:
¡P Generate data for the description of the geometry of the buildings and the surrounding terrains in a selected geographical region in Hong Kong;
¡P 
Allow users to choose the boundaries of the
area within which the building and terrain geometric data are required, to
edit the geometric data to incorporate new buildings within the area or to
make changes to the buildings and the terrain geometry, and to choose the
data format for exporting the data that would meet the specific data input
requirement of the simulation program to be used in the study, e.g. computational
fluid dynamics (CFD) simulation of air-movement around the buildings; and
¡P Allow users to predict the solar and daylight intensities at the façades of the buildings, taking into account the inter-shadowing effect of adjacent buildings, and the simultaneous cooling demand of a large number of buildings in a district through using the calculation routines linked to the front-end of the program.
The project is intended to be a pilot study for the development of a more comprehensive program that will embrace a geographical database that covers the entire Hong Kong. The study focuses on developing the methodologies required for realising the abovementioned functions, leaving the more laborious tasks of repeating the methods for expanding the database to cover the entire Hong Kong to be done when subsequent funding can be made available.
Development of a multi-criteria decision making model for sustainable building development for Hong Kong
(HK$421,600, Research Grants Council)
With the increase in public awareness of environmental issues during the late 1980s and early 1990s, sustainable development is becoming one of the major policy issue of the Hong Kong SAR government. Policy makers are now facing additional challenges on how to prioritize the allocation of limited community resources in environmental issues. The most cost effective and efficient manner is through imposing statutory controls on issues that are most neglected and less focused by the developers and building designers. In achieving this, a model to predict how the developers and designers act when confronting with a set of diverse design issues is needed.
The principal objective of this research is to formulate a model to predict how designers and developers in Hong Kong will perform when they are confronted with tradeoff during a complicated design process. This in turn will become a decision making tool for the policy makers to formulate environmental strategy at the most effective way. The findings of this proposed study can help to reveal the amount of money that developers are willing to pay for various design attributes, ranging from aesthetics, indoor air quality, acoustical performance to environmental impact.
The long-term significance of this study is to enhance our understanding of the behavior of developers and designers towards a diverse set of design issues. This understanding can provide insight for the policy makers to formulate a regional strategy for allocating the limited community resources in the most effective and efficient manner during their pursuit of sustainability excellence. The major value to policy makers lies on how statutory controls should be imposed on issues that affect the social and environmental cost for a district, city, country or region at large. The proposed study can also help to train students to gain interdisciplinary knowledge and experience in building design and impact assessment process.
Determining Resource Impact Factors for Buildings in Hong Kong
(HK$198,000, The Hong Kong Polytechnic University)
The principal objective of this study is to develop a set of resource impact factors for evaluating the potential environmental impact of the various environmental stressors. The primary focus of the environmental stressors in this study is energy use and recycling. Besides, it is the intent of this study to develop a systematic approach to derive a weighting scale for various environmental stressors. In this study, a new weighting scale based on the relative potential impact of various environmental stressors will be derived.
The long-term significance of this study is to enhance our understanding of the potential impact of environmental stressors. Furthermore, the proposed study can potentially contribute to the formulation of a more valuable building assessment scheme for Hong Kong, which in turn would lead us to use our resources more effectively and efficiently.
Energy Policy for Building Environmental Performance Model in Hong Kong
(HK$83,722, The Hong Kong Polytechnic University)
From a previous study, the energy consumption between the traditional and Building Environmental Performance Model (BEPM) air conditioning system was calculated. The coil load for the traditional air conditioning system in the measuring year of a building was 15,104,054 kWh. With the integration of the BEPM, the total coil load was 14,020,000kWh, with percentage saving of 7.15%. For the fresh air load, the energy consumption of the traditional system was 2,690,000kWh and with the BEPM was 2,250,000 kWh, with percentage saving of 16.4%. The total energy saving was 1,520,000kWh for the updated system. Assuming the unit cost of the electrical bill was HK$ 0.86 per kWh, the saving of the energy cost was more than HK$ 1.3 million per year. Therefore, when BEPM concept is promoted to all the air conditioned building in Hong Kong, a huge amount of saving in energy cost can be achieved.
This study aims to enhance and prompt the conventional operation of
the air-side system by incorporating temperature reset with adaptive comfort
temperature control, in order to save energy, by achieving a realistic adaptive
comfort temperature. Together with the new demand control ventilation system
and other quantified uncontrollable system parameters, the energy required
to combat the hot and humid climate in high-rise buildings in Hong Kong will be more effectively used.
A novel approach for resolving the priority issues in the building energy and environmental assessment scheme for Hong Kong
(HK$240,000, The Hong Kong Polytechnic University)
Many voluntary building environment assessment schemes have emerged around the world as tools intended to improve environmental performance and help achieve sustainability. The voluntary approach, offers greater flexibility for building owners to reach targets so as to gain a better public image, and is useful for the policy makers to promote dialogues with the private sector and to raise public awareness of environmental issues. The assessment process is usually conducted by comparing the assessed building against a set of prescribed quantitative and qualitative performance indicators of diverse objectives. Credits will be awarded to the assessed building once the listed criteria are fulfilled, to offer encouragement in achieving the environmental objectives. To ensure a successful voluntary environmental assessment scheme, the credit allocation strategy adopted should be able to award more credits to the profit-oriented developers for a diminishing economic return.
This research is to formulate a strategy of incorporating developers¡¦ economic interests into the credit weighting structure of Hong Kong Building Environmental Assessment Method (HKBEAM), and to provide insight for the scheme owners and policy makers to rescale the current weighting allocated to the diverse objectives. The formulation of credit weighting scale begins with the development of Economic benefit-cost ratios and Environmental impact-cost ratios for various criteria. This will help the developers to prioritize criteria selection for achieving a maximum number of credits at a minimum cost under the current assessment scheme; to enhance our understanding of the potential impacts of performance indicators economically and environmentally; and to train the students to have the multidisciplinary perspectives in building environmental impact assessment.
Life cycle energy analysis of building construction
(Contract research project, Electrical and Mechanical Services Department, HKSAR Government)
Sustainable building development requires a clear understanding about the environmental and economic impacts of buildings, from cradle to grave, and how the impacts can be minimized through optimizing the design. The project involves the development of a Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) tool for commercial buildings in Hong Kong. The tool is to include a database on life cycle impacts and costs for various building materials and services systems and an efficient recurrent energy use prediction model.
According to ISO 14040, an LCA involves four interacting stages, including goal and scope definition, inventory analysis, impact assessment and result interpretation. Although LCA models for buildings are available from overseas vendors, the inventory databases that accompany such models contain data that are specific to their respective places of origin. For applications in Hong Kong, such data would need to be edited to reflect the actual situations in the local construction industry. Corrections to the inventory data to be made include the energy mix in the countries of origin from which Hong Kong imports construction materials, the energy use and the associated impacts incurred due to transportation of the materials to Hong Kong, the energy use and waste generation due to local construction activities, and the demolition of buildings and treatments for the construction and demolition (C&D) wastes.
Unfortunately, LCA is, as yet, a new concept
seldom practiced in Hong Kong, and virtually no life cycle inventory data are available.
The approach that will be taken is to use, as a starting point, inventory
data that are available in established databases that are commercially available.
The unit processes involved in the production of each building material/component,
from extraction of raw materials through disposal of the building material/component,
and the impacts associated with each unit process, will be identified. Those
unit processes that are significantly different from local practices (e.g.
construction methods and C&D waste handling) would be replaced by data
that are appropriate to local situations; and processes missing (e.g. shipment
from place of production to Hong Kong) will included. This requires a detailed
understanding of what types of building materials and services systems are
used in commercial buildings in Hong Kong, the construction processes used in building
sites, any off-site processing and pre-fabrication work, and C&D waste
handling in Hong Kong.
These form the objectives of the survey part to be undertaken in the proj
ect.
Since the life cycle energy use of a building and to a large extent the life cycle cost of the building as well is dominated by the re-current energy use during the occupied stage, the LCA/LCC study should include predictions of the impacts of using alternative building design features on the re-current energy use. Given that numerous options may be considered during the design stage, an efficiency simulation tool that can account for the effects of changes in use of materials is essential. The development of a building energy prediction model that can satisfy this need is also included as a part of the project work.
Building Operation and Maintenance
Researchers : Dr K T Chan (leader), Mr Joseph H K Lai, Prof Francis W H Yik
Collaborator
: Prof P Jones, Welsh School of Architecture, Cardiff University,
Research Student : Mr Ringo H K Lee
It is essential that the building services systems can function to satisfy the user expectation and provide healthy and safe indoor environments. While achieving these requirements, it is also important to keep down the operating cost and maintain a high standard of service. This requires a proper design of the systems, a sound operating strategy, and an effective maintenance programme. Research work on O&M aims to benchmark the performance of installed services systems, establish energy effective operating strategy and preventive maintenance programme, develop methods to improve system efficiency in a cost-effective framework, and provide feedback of system operation to the design process.
Research Projects
Development of operation and maintenance strategy for systems performance optimization of hotel building services
(HK$505,321, Industrial Support Fund, with Hotel Grand Stanford Inter-continental)
This research project is undertaken under a Teaching Company Programme set up between The Hong Kong Polytechnic University and the Grand Stanford Inter-continental Hong Kong.
In hotels it is essential that the building services systems can function to satisfy the user expectation and provide healthy and safe indoor environments. While achieving these requirements, it is also important to keep down the operating cost and maintain a high standard of service. This requires a proper design of the systems, a sound operating strategy, and an effective maintenance programme.
The scope of this research project is to evaluate
the performance of the hotel's existing services systems and to develop methods
to improve system efficiency in a cost-effective framework. The existing systems
will be investigated for any necessary retrofitting for energy conservation
and environmental protection. This includes evaluation of the system retrofitting
alternatives and development of energy effective operating strategy and preventive
maintenance programme.
To realize the objectives of this project, it requires a close involvement in the operating and maintenance activities in the hotel. A teaching company scheme will best suit this requirement by appointing a teaching company associate (TCA) to work with the hotel maintenance team for two years.
The rationale for effective operation and maintenance of building services systems has been receiving much less attention than it deserves. Also, system designs are often developed with little concern on operation and maintenance requirement. This project will contribute to the development of a rational approach to achieve effective system operation in hotels, and will demonstrate an example in the feedback of the operation and maintenance experience to design.
Progress has been to:
¡P Evaluate the performance of the existing systems through a detail energy audit;
¡P Establish operation and maintenance structure;
¡P Analyse effects of O&M on energy and environmental performance;
¡P Establish schemes for maintenance decision making;
¡P Develop models for cost-effective maintenance and criteria for maintenance performance assessment.
Economic, management and contractual considerations in outsourcing operation and maintenance work for commercial buildings
(Staff development programme, The Hong Kong Polytechnic University)
Operation and Maintenance (O&M) work in buildings is traditionally undertaken by in-house O&M staff employed directly by building owners. In recent years, the economic downturn triggered downsizing of companies, which is often associated with outsourcing the building O&M work.
The success of outsourcing hinges on a complete set of equitable and enforceable contractual conditions, which should be able to clearly define the obligations and liabilities between the employer and the contractor. Inevitably, forming, enforcing and monitoring the contract work will incur transaction costs although the benefit of reduction in in-house manpower resources may outweigh these transaction costs. All in all, the total costs and benefits, both pecuniary and non-pecuniary, should be thoroughly scrutinized before an outsourcing decision is made.
Problems are often encountered in executing/managing outsourced O&M contracts, which arise from such as ambiguity in defining the demarcation of the scope of the contract work, varied interpretation of contract terms and unwillingness of in-house staff to cooperate with the contractor. Investigating the causes and finding solutions for these problems should be of great value to the industry.
With regard to the topic, a research study with the following objectives has commenced in Jan 2003:
¡P To investigate the current management practices in in-house and outsourced operation and maintenance (O&M) work in commercial buildings.
¡P To investigate various problematic contractual conditions taking into account relevant statutory requirements and trade practice in outsourced O&M contracts.
¡P To evaluate the performance of outsourced O&M contracts from monetary and quality service viewpoints.