Filtering through harmful contaminants

Dust and contamination are not visible to our naked eyes.Using right filters is the way to go

Reducing ventilation and sealing living spaces more tightly are ways to conserve energy, but they are also trap irritants. Particulate contamination, like dust and pollen, can make you sneeze, cough, irritate your eyes – you know the feeling. Disposable fiberglass filters are certainly inexpensive; but if clean air is important to you, disposable filters aren’t really acceptable, because they only remove large particles and not the tiny particles of dust, pollen, and smoke.

Reasonable estimates are that the visible particles that scatter a sunbeam’s light amount to one per cent of all the particles in the air. That leaves another 99 per cent too small to be seen with the naked or untrained eye. Only the effects of these invisible particles may be seen in human discomfort and in soiling film that slowly coats walls and furnishings.
Dust, pollen, tobacco smoke, cooking smoke, bacteria, viruses, skin flakes and carpet fibres are some of the troublesome particles floating in indoor air. These particles are suspended in the air until they attach themselves to walls, furniture, drapes, etc. Scrubbing, dry cleaning, painting and redecorating are required to undo the damage they cause.

Indoor air pollution
Worse yet are the effects dirty indoor air has on people. Pollen, spores and dust make life miserable for those with allergies. Lingering tobacco smoke makes some people acutely uncomfortable. Bacteria and viruses promote disease and these particles are carried through the air with the aid of dust.

Formaldehyde is another potentially harmful gas which is generated from furniture, building materials, and insulation and can be found in almost any home. While air pollution affects everyone there are studies that show our children are even more susceptible to the detrimental effects of air pollution particles than adults.

Good air distribution system
Kenneth Gong, BSc, MBA, MASHRAE, Technical Manager, TROX Malaysia Sdn Bhd, says, “After the outdoor supply air has been filtered to an acceptable level, it will be air-conditioned before it is distributed throughout the building where ventilation and air-conditioning is required.”

He suggests that the HVAC system should be properly tested, balanced and set into operation in accordance with recognised commissioning standards before the building is handed over to the building owner. Poor air distribution can lead to:
• Stagnation, resulting in the lack of fresh air and hot spots
• Down draft (local cold spots)
• Excessive noise from the ventilation system

Low level ventilation systems, in particular, are known for “their high contaminant removal efficiencies and their possible energy savings, especially in relatively mild climates”, according to ASHRAE. Such system can be either under-floor air distribution (UFAD) system or displacement ventilation system

Good maintenance management
Gong also suggests regular maintenance of HVAC systems, which is a very important factor in maintaining good IAQ. “Air filters should be checked and changed regularly before it exceeds the manufacturer’s recommended maximum pressure differential across the filter. Poor maintenance of the HVAC system can lead to excessive fan energy consumption because of dirty heat exchangers and excessive pressure drop across the air filters,” he adds.

Maintenance of filters
Frank Taaning Grundholm, Vice President – Global HVACR Sales – Drives, ABB, says, “If you have pollution outside and you don’t do anything, then you’re going to have pollution inside when you ventilate the building. And, if you don’t ventilate the building you’ll still have air pollution — CO2 pollution.”
He further states, “We do need ventilation, but we need to apply the relevant filtering so that we can prevent the particles from entering the building. We need to make sure that filters get replaced on the building at the right time.”

Improving efficiency in HVAC systems
High efficiency products are necessary, says Frank. “Unfortunately, these efficiency requirements are set at full load. But, when you look at traditional HVAC systems, most of them operate 99 per cent of the time at 80 per cent load or less. But, nobody specifies the efficiency at part load. So, we’re actually working with the community on how we can improve specifications to achieve the energy savings that the customers expect.”
When the part load efficiency is significantly lower you will never realise the savings that you had calculated. That’s why, when selecting solutions, it’s necessary to look at the load profile of the building based on the actual location of the building.

“When you have a relatively flat efficiency curve and use high quality components, then of course the price comparison doesn’t fit at an initial cost perspective. However, if you look at the lifecycle of a building and the sustainability of a project, it is relevant. And it is value that we are adding, because most of the time you’re operating at part load and you need the high efficiency at part load condition as well,” says Frank.

HVAC system should be properly tested, balanced and set into operation in accordance with recognised commissioning standards
Kenneth Gong, BSc, MBA, MASHRAE, Technical Manager, TROX Malaysia Sdn Bhd

We need to make sure that filters get replaced on the building at the right time
Frank Taaning Grundholm, Vice President – Global HVACR Sales – Drives, ABB