By Wei-nee Chen

A NEW ERA INTRULY SUSTAINABLE BUILDINGS

Pusat Tenaga Malaysia PTM (Malaysia Energy Centre) is a Government agency administered by the Ministry of Energy, Water and Communications Malaysia. PTM was registered on 12th May 1998 and the role of PTM is to function as a one-stop centre and implementing agency on national energy related matters. PTM is also the National secretariat for Clean Development Mechanism (CDM) programme for the Energy Sector. PTM houses several projects supported by the United Nations Development Programme and Global Environment Facility.

Some of these projects include:

• Malaysia Building Integrated Photovoltaic (MBIPV) Project;
• Malaysia Industrial Energy Efficiency Improvement Project (MIEEIP);
• Biomass Generation & Co-generation in the Malaysian Palm Oil Mill (Biogen) Project.

In 2004, the idea of constructing a zero energy office was mooted and PTM, being the centre for advocating energy efficiency and renewable energies is the ideal platform to showcase the proof of concept that zero energy office (ZEO) is feasible. By March 2006, construction was on the way and on 1st November 2007, PTM officially moved into the ZEO building.

The solar array panels of Enterprise 4, Technology Park Malaysia is said to be the largest of its kind in Malaysia.

PTM ZEO is designed to be the first building of its kind in South East Asia to aim for the zero energy status. The building is designed to achieve building energy index of 40kwh/m2/yr. A typical building in Malaysia has building energy index of 200 – 300 kwh/m2/yr while the Low Energy Office (LEO) building of the Ministry of Energy, Water and Communications in Putrajaya has an index of 100 kwh/m2/yr. The benchmark to qualify as energy efficient building as defined in Malaysian Standards MS1525:2001 is energy consumption of not more than 135 kwh/m2/yr.

The concept of ZEO is simple, the building pushes the limit of energy efficiency to a maximum and the remaining electricity requirement by the building is met by electricity generated by solar photovoltaic systems. The ZEO is constructed on a 5-acre site located in Bandar Baru Bangi, just 40 km south of the heart of Kuala Lumpur city. Today, the PTM ZEO represents a prototype building serving as benchmark for sustainable energy solutions for the building sector in the country and surrounding region. The total floor area of the ZEO stands at approximately 4,000 m2 and is able to accommodate up to 111 staff. Overall, the building incorporates energy efficient features utilising active and passive techniques.

The following are the key features of the ZEO:

Office Lighting
As much as possible, the office utilises the sun for natural day lighting. As such, the building is strategically orientated so the length of the building lies along the sun path (i.e. eastwest) which means reduced direct sun light along the northsouth orientation of the building. The windows are positioned on the north-south orientation of the building which allows maximum day lighting. To prevent the discomfort of direct heat due to sunlight all windows have high performance glazing or sealed double-glazing (spectrally selective glazing) which reflects ultraviolet and infrared radiation from the building exterior surface. This way, less radiant heat gets in and the building still benefits from natural day lighting. Thermal insulated wall at the east-west facades also reduces heat absorption. Lightings in the office are controlled by sensors. Lights in common areas (e.g.walkways) will only be switched on when the sensor detects movement. In working office areas, lights are switched on only when illumination level falls below a preset level. All lightings are fitted with high energy efficient T5 miniature fluorescent tubes.

Cooling
Air conditioning in office buildings consume a very high amount of electricity. In the PTM ZEO, radiant cooling contributes 75% of cooling requirement while the remaining 25% is via convectional (chilled) air flow. The radiant cooling effect is achieved by floor slab cooling in which water pipings are embedded onto the concrete floor slabs. Chilled water runs through the pipes and this produces the radiant cooling effect. The floor slab cooling system comprises of a thermal storage which operates during the night and by day, the system is automatically off. The air condition condenser system is also cooled by night and this is achieved by drawing heat from water in the heat exchange of the condenser system. The water flows along the solar PV roof which acts heat sink to draw the heat from the water. Heat loss from the water is also achieved by evening ambient cooling and evaporation.

Lush greenery features around the building indirectly affect the microclimate of the area, and reduce “heat island effect”.

Humidity Control
The building is designed to being air tight. The rational for observing such high degree of air tightness is that dehumidification of air quality in buildings consumes a great amount of electricity. Dehumidifying is critical as it affects human comfort in the office environment and high amount of humidity in the office runs into the risk of internal condensation due to radiant cooling effect. The preservation of air quality is achieved via the process of dehumidification. A desiccant heat wheel that operates by replacing incoming hot and humid fresh air with cooler and drier exhaust air is used to counteract this effect.

Rainwater harvesting is one water conservation measure that can be easily practiced in most commercial buildings. The design and implementation of the system is relatively easy and inexpensive. By capturing rainwater for non-consumable purposes, the building will reduce demand on the municipal supply thus alleviating some of the water supply stress in the country. In PTM ZEO, rainwater is use for condenser side cooling system and irrigation. The use of piped water is only 1/3 of the total amount of water used.

Solar Photovoltaic Systems
While energy efficiency features lower the energy consumption by the building, the remaining energy supply will be met by solar photovoltaic (PV) system. It would be accurate to say that most of the features mentioned earlier are not tangible to the eyes, the solar PV systems in PTM ZEO provides the visible hallmark in setting the standards of a truly zero energy office.

The incorporation of solar PV systems was timely with the commencement of Malaysia Building Integrated (MBIPV) Project. Ir Ahmad Hadri Haris, the National Project Leader of the MBIPV Project together with his team of PV experts designed and managed the implementation of the country’s first large scale grid-connected BIPV systems in office buildings.

In the design phase of the building, PTM decided that the ZEO building will showcase:

1. the major PV technologies namely monocrystalline, polycrystalline, amorphous thin film and themonocrystalline glass;
2. true building integrated photovoltaic (BIPV) and optional concept of BIPV (retrofitting).

Semi-transparent PV glass systems allow for natural day lighting in the atrium

Hence, the PTM ZEO today showcased four different PV different technologies. The largest PV capacity at the PTM ZEO showcased 47.28 kWp (kilo watt peak) polycrystalline BIPV system on the main roof. The second PV system was the 6.08 kWp amorphous silicon BIPV system. The third PV system (also dubbed the prima donna showpiece) highlights the grandeur use of the 11.64 kWp monocrystalline glass glass BIPV system in the atrium of the building. Lastly, the car park roof has been integrated with 27 kWp monocrystalline BIPV system.

The PV systems at PTM ZEO are all connected to the grid. No batteries or charge controller systems are utilized. Instead the utility’s grid serves as a huge battery bank for PTM to route any surplus electricity during the day time and at night, when the PV systems take a nap, electricity required to run the base load is drawn from the grid. This arrangement of grid interconnectivity is agreed by Tenaga Nasional Berhad, the Malaysian electricity utility under the net-metering scheme. This scheme is also applicable to other buildings in Malaysia (both residential and commercial) implementing solar PV for their own uses. The total PV capacity for PTM ZEO is 92 kWp and this translates to a target of 101.2 MWh electricity generated per year. This is based on the PV energy yield of 1,100kWh/kWp per year for the Klang Valley. The actual performance of the PV systems can be viewed at the following website, http://pvmc.uitm.edu.my/pvmc/.

Walk the Talk
Today after 4 years of planning, designing and construction, the ZEO is finally completed. While talk has been cheap, PTM today has lived to its calling. Being a Government agency specializing in energy efficiency and renewable energies, the ZEO embodies the core reason for the organization’s existence. The challenge set is for the rest of the nation and surrounding neighbours to join in the new era of constructing truly sustainable buildings.

Wei-nee Chen is a Technical Advisor of MBIPV Project. Feedback on the subject of solar PV is most welcomed. Email: weinee@mbipv.net.my