Ignoring Indoor Air Quality (IAQ) is dangerous. In China, it is estimated that 3 million children under the age of five die from respiratory problems caused by both indoor and outdoor air. Although the design and technology of air conditioning systems has advanced, the way they deliver air has not. An Australian innovation aims to change that.
Many indoor areas are air conditioned with either an evaporated or refrigerated air conditioning system. The evaporator provides air with a moisture content (around 45 per cent is healthy and recommended) and is usually released from the indoor space through an open window. It is basically outdoor air blown through wet pads to produce a cooling effect.
The refrigerated air is cooled by gas and may be released from the room in the same manner as evaporated air, or it can be recycled. It is totally dry air that can cause dry skin, sore throats and stinging eyes. Releasing air through windows and open doors can be a security problem or it may allow polluted air from outside to enter the indoor space.
In most cases, recycled air is dirty air. The already polluted indoor air is drawn through a filter before cooling and being sent back into the same indoor space it came from. The need for constant vigilance in cleaning filters or replacing them on a very regular cycle will help, but this is often ignored. Therefore, Indoor Air Quality (IAQ) is totally compromised by air-conditioning systems which have progressed in their designs and technology but still deliver the air product in the same manner as they did over 60 years ago.
The problem, according to Stuart M Innes, director of SISACS, is that manufacturers are generally focused on the product and the technology they incorporate rather the air itself.
“Acknowledging the known issues with air-conditioners is the first step to superior IAQ,” he said. “Ideally, owners of air conditioners should be able to expect the delivery of the 'air' product to be constantly 100 per cent clean, free from germs and pollutants whilst providing the appropriate moisture content. C02 should be, by preference, in the area of 300 to 400 parts per million or less.”
The current status is that the already poor quality “air” product is delivered either directly from a wall mounted unit or through a diffuser mounted in the ceiling. It may also come from a window installation or from a unit mounted on the floor against a wall. This random air-conditioning delivery system, Innes says, is badly flawed in that it has no logical methodology for the “air” to be efficiently delivered and used or for the internal air to be effectively removed.
The SISACS innovation addresses this issue.
“Physics tells us that hot air always sits above cool air,” said Innes. “It is therefore reasonable to believe that the 'air' product should always be delivered at floor level. If this is the case then it is also reasonable to believe that the existing and polluted warm air in the room should be removed at ceiling height. If the room is to be warmed then the opposite delivery method would apply.”
By extracting the air being constantly introduced into the indoor area at the same time and at the same rate of litres per second into the ceiling cavity, the internal space is constantly being supplied with clean fresh air while simultaneously having the air extracted. The ceiling cavity receiving the air which has only been in the internal space a very short period of time will still be cool and help maintain effective insulation. For this method to work, the ceiling space is simultaneously evacuated as well.
The end result is that all airborne germs and other allergens or particulates, including leeching chemicals, are constantly being swept from the indoor air space while being replaced with healthy new air.
As the world’s first hybrid air handler using both evaporative and refrigeration to cool, there are also energy saving benefits. If the system is operating in evaporative mode and the relative humidity has risen to a level where cooling is compromised, it will automatically shift into refrigeration mode. The dual operation saves energy while saving on water usage from mains supply.
IAQ is not complete without a method of addressing Co2 buildup, which will occur no matter how well filtered the air is. SISACS has introduced a method of Co2 capture from ambient air utilising a patented sorbent on a frame attached to the induction part of the air handler, which has the ability to remove more than 60 per cent of the Co2 being inducted into the air handler. The 'air' product is now not only pure with its filtration process but it is scrubbing the inducted air to provide air quality with a low Co2 level, which in turn is being constantly removed from the internal air space, thereby eliminating any build up.
Australia generally has around 400 parts per million of Co2 in its ambient air but this figure can vary considerably due to many issues. Overseas countries can constantly see Co2 levels above 800 parts per million or more.
“Harvesting Co2 from ambient air utilising a sorbent has been possible for some time but the energy required to move ambient air has always discouraged innovators,” explained Innes. “They have opted for the easy harvesting of Co2 from thermal power chimneys and others.”
“We are now able to capture food grade Co2 which has a value in two directions,” he continued. “One is the carbon points able to be accessed and traded on the carbon exchange and the other is the provision of Co2 for algae ponds to fast grow bio diesel or spirulina. The process can be fast-tracked using the right Co2 in algae ponds by up to 300 per cent.”
The Co2 frames designed for SISACS can be attached to other air conditioning brands or anything with an operating fan. There are about 53 million individual HVACR installations in Australia generating about 12 to 14 per cent of national greenhouse gas (GHG) emissions. It is estimated that should each machine be installed with these filters, the carbon abatement required by Australia by 2020 would be achieved just through this method of Co2 capture.
When the frames are full, they are easily replaced and the Co2 can then be harvested with a heat process and the frame reused again. There is no limit to the longevity of the Co2 sorbent within the frame.
“There is no reason why the collection and redistribution of Co2 frames could not be a council operation that follows the same model as recycling,” said Innes.