Cover Story


Cover Story: Energy Saving in Buildings

Strategies for energy saving in buildings

The world is now facing a crisis of global climate change resulting from excessive emission of greenhouse gases. The major source of greenhouse gases is the burning of fossil fuel in the process of energy production. Therefore, energy saving is one of the key measures in combating greenhouse gas emissions. Nowadays, buildings are the largest energy consumer accounting for over 40% and 80% energy consumption in the US and Hong Kong respectively. Thus, energy saving in buildings is emphasized in the management of buildings not only to save money but also protect the environment.

To save energy in buildings or to maintain energy efficient buildings, there are three basic approaches :

  • Reduced heating/ cooling loads
  • Use of energy efficient and green components and technologies
  • Optimization of system and technology integration, operation and control

Prof. Shengwei Wang (Chair Professor of the Department of Building Services Engineering of PolyU), a renowned scholar in building energy management, explained that the first two approaches involve design and application of modern technologies which are not difficult to achieve provided that proper design and facilities are selected. However, having energy efficient facilities in place would not guarantee a save of energy for the buildings since such facilities may not be properly integrated into the building services management system. Therefore, the third approach of optimizing the system and technology integration, operation and control is very important. This is also the research interest of Prof. Wang.

Life-cycle diagnosis/ commissioning and optimization

Problems of building facilities causing energy waste may come from various stages of the entire building life-cycle, including improper design, component sizing and selection, installation, operation and control. Prof. Wang applies the concept of "life-cycle diagnosis/ commissioning and optimization" in his research in order to maximize the energy efficiency of existing/ new buildings. In an existing building, to diagnose deviations of energy efficiency performance of facilities from its designed intents, it is necessary to perform building energy audit and building system evaluation before formulation of any building energy saving plan, upgrading system operation and control strategies. For new buildings, energy saving can be achieved by commissioning and optimization of system configuration/ selection, monitoring and control instrumentation/ systems, as well as developing optimal and energy efficient control strategies.

Prof. Wang and his research team have been involved in building energy management projects of many famous buildings in Hong Kong. For example, his team has been working as the independent commissioning agent for the super-high-rise building in Hong Kong, the International Commerce Centre (the tallest building in Hong Kong with 108 floors and floor area of 440,000 square meters) over the last five years, starting from the HVACR design through construction, testing/ commissioning and operation. The energy saving of the above diagnostic and optimization efforts is over 7,000,000 kWh per year, which is about 16% of the HVAC system energy consumption. Besides, Prof. Wang also contributes to the saving of energy in buildings of our campus by serving as a professional consultant in the Campus Sustainability Committee of PolyU.

More about energy saving in buildings of Hong Kong

With a view to promoting energy saving in buildings, the Electrical and Mechanical Services Department (EMSD) of the Hong Kong SAR Government has launched many voluntary energy saving schemes for buildings. These include the Energy Audit Programme, Fresh Water Cooling Towers Scheme for Air Conditioning Systems, HK Energy Efficiency Registration Scheme for Buildings, etc. A new legislation, Building Energy Efficiency Ordinance (Cap. 610, Laws of Hong Kong SAR), will be enforced on 21 September 2012. This Ordinance requires that certain types of buildings must comply with minimum energy efficiency standards for building services installations such as lighting, electrical and air-conditioning system, as well as lift and escalator. Prof. Wang welcomed this legislation as it is a good step towards energy efficiency of buildings in practical operation. However, he remarked that most current legislations provide standards of reference to the design and installation of building facilities only, they may not guarantee the stated energy efficiencies are materialized in practical operation. In general, there is an energy saving potentials of 10 – 20% and 20 – 30% for new and existing buildings respectively if their facilities are properly commissioned/ diagnosed and integrated into the building services management system.

Good practices can further help

Apart from the building energy saving strategies as mentioned above, Prof. Wang would like to emphasize that good practices can further help to save energy in buildings especially after office hours. From his experience in life-cycle diagnosis for existing buildings, Prof. Wang observes that significant amount of energy can be wasted via the HVAC systems in buildings if they are not switched off after office hours. Lighting and office equipment such as computers, printers, and photocopying machines that are not powered off or remain in standby mode are other sources of energy waste in non-office hours. Therefore, adopting good practices to switch off all unnecessary electrical appliances before leaving the office can certainly contribute to the saving of energy in buildings.


Activities and Development on Campus

PolyU supported Earth Hour 2012

PolyU continued to support the Earth Hour campaign organized by WWF. Earth Hour 2012 was held on 31 March 2012 from 8:30 pm to 9:30 pm.

Our academic departments and administrative units responded enthusiastically with different supportive actions including the encouragement of staff and students to switch off unnecessary lighting in areas within their control, no matter on the campus or at home.

In our Library, all idle computers, copiers and printers were switched off. Non-essential lights in zoned office areas, especially those facing the Cross Harbour Tunnel and the garden, were also switched off.

For the public areas on campus, our Facilities Management Office switched off most of the non-essential lighting including lighting for the fountain, flood lights, corridor, covered walkway, facade, waffle and landscape lighting as well as the lights for the PolyU logo at Core D.

The Student Affairs Office also supported the event by closing its soccer pitch and tennis courts during the period of this event.

At the Student Halls, the Green Green Hall Community, a student organization, had organized a sign-up campaign to appeal for their residents’ support for the event. Also, the event’s student ambassadors went to remind fellow hallmates to turn off their lights during the period.

PolyU is proud to have joined this campaign together with all other tertiary institutions, 340 schools and about 3,300 other buildings in Hong Kong. We anticipate that more Hong Kong people will be aware of the seriousness of global climate change and take action to save energy and reduce greenhouse gas emissions.

Teaching Hotel Complex won the Silver Award of the Skyrise Greenery Awards 2012

The Teaching Hotel Complex of PolyU won the Silver Award of the Skyrise Greenery Awards 2012 organized by the Greening, Landscape and Tree Management Section of Development Bureau. The Awards aims to promote the development of quality skyrise greening, and to give recognition to exemplary projects that showcase the integration of skyrise greening into the built environment of Hong Kong.

The Teaching Hotel Complex has three components including Hotel Icon, School of Hotel and Tourism Management, and the Staff Quarter. To integrate the greenery design with the architectural concept of each individual space, it starts with a three-storeys high interior green wall inside the hotel main entrance lobby and continues upward to various locations and transforms to different kinds of green features such as exterior green wall, green roofs and landscaped roof terraces.

Innovative green kitchenware products designed by PolyU students

PolyU students showcased a wide range of innovative kitchenware products at the Hong Kong Houseware Fair held at the Hong Kong Convention and Exhibition Centre from 20 to 23 April 2012. These products were designed by engineering students of PolyU under the KitchenGala project, a unique industry-university project of the University and King's Flair Development Limited to nurture students' creativity in product design and development with due consideration on environmental protection.

Seminar on the Building Energy Efficiency Programme

A half-day seminar for the Building Energy Efficiency Programme (BEEP), which was supported by the Environment and Conservation Fund of the Hong Kong SAR Government and the Department of Building Services Engineering (BSE) of PolyU, was successfully held on 25 May 2012. A number of professionals, officials and scholars gave presentations in this seminar that attracted lots of participants coming from a wide spectrum of stakeholders of the building industry. 

Seminar on "Go Low Carbon"

The Faculty of Business and the PolyU MBA Alumni Association jointly organized a seminar entitled “Go Low Carbon” on 9 June 2012. With three distinguished speakers from the business, product design and environmental sectors, this seminar focused on the science behind climate change, its impacts on human, society and ecology, and ways to reduce carbon footprint through low carbon living and design, which were very well received by the audience.


Resources Conservation

Used-items collected for the needy

The Used-items Collection Campaign was held again on campus on 23 May 2012. The campaign was jointly organized by PolyU Staff Association and the Community Recycling Coop of the Industrial Relations Institute, which is a government-approved charitable organization in Sham Shui Po. The campaign had been held many times on campus since 2008 and it had received enthusiastic response from the PolyU community.

A total of 360 kilograms of used items were collected in the event. The collected items, all in good conditions, including electrical appliances, clothes, shoes, bags, stationery, books, CD, DVD, household goods, and bedding and furniture items, etc. were to be sold to the needy at very low prices. This event not only helps the low-income people in Hong Kong, but also spreads the message of cherishing and sharing resources.


Pollution Control

Spraying of pesticides in indoor areas

In Hong Kong, the Agriculture, Fisheries and Conservation Department (AFCD) regulates the active ingredients and their maximum concentrations in pesticide products. Only active ingredients with an AFCD registration number (in the form of 1PXX or 2PXX) are allowed to be used.

At PolyU, pest control work is carried out by pest control contractors appointed by the Facilities Management Office (FMO). FMO, upon receipt of the pesticide information from its pest control contractors, will forward the information to the Health, Safety and Environment Office (HSEO) for comment. HSEO will vet the technical bulletin on the pesticides to ensure that the active ingredients used in the pesticides are registered with the AFCD and that the pesticides are suitable for general use. Moreover, HSEO will give specific advice on the health and safety precautions (when deemed necessary) that should be followed when such pesticides are applied.

As you may be aware, improper use of pesticides may result in adverse health effects on the pesticide users and other building occupants alike. These health effects may be serious, particularly for people who might be hypersensitive to specific chemicals. Therefore, it is not advisable to bring your own pesticides and spray them in an indoor environment. If you encounter any pest-related problems in your workplace, you should approach FMO to make arrangements for relevant pest control work.


News and Tips

Tips on electricity saving on the campus

Electrical appliance and equipment left in standby mode do consume energy. When they are not being used for more than ten minutes or so, it is necessary to switch their powers off.

Screen savers are not energy savers, they are designed for saving the screen from burn-in. Shut down computers and monitors properly at the main power switch when they are idle.

Switch off photocopiers and printers at night and at weekends. Only print if necessary so to save energy as well as paper.

Switch the lights off when you leave your office or workplace for lunch or meetings, especially when you leave for home.

Besides, switch off the air conditioning when you leave for home. Keep windows and door shut when the air conditioning is running. Set the temperature not too low so that you feel comfortable rather than cold. In an air conditioned room, a box fan can effectively create cooling effect with far less energy consumption. For more details about energy saving in the office, please refer to the Electrical and Mechanical Services Department's booklet at