Revolutionary air conditioning technology has provided a Sydney construction company with the solution to a problem that threatened to stall construction of a York Street building.

Building development company Toga Group was faced with a "no-go" prospect when local building height restrictions limited the proposed 117 York Street building to 12 floors, making it unprofitable as a rental investment.

Toga Group Executive Development Manager Scott Gregg said conventional architecture and air conditioning systems meant that only 12 floors could be built within the given height restrictions on the site but that 13 were needed to produce a viable rental return.

The number of floors achievable on a given site with restrictions is determined by the slab-to-slab height which, in turn, is determined by the minimum internal floor-to-ceiling height plus the ceiling space required for air-conditioning ducting and other services. That can sometimes require more than half a metre between the ceiling and the slab above.

Toga Group's services consultants, Adamus Consulting Practice, referred Toga to an Adelaide company, DADANCO, that had not only developed some new air-conditioner technology for refurbishing existing induction units, but had used their invention to make new induction units that required less ceiling space.

Perimeter zone induction systems deal with transmission loads through external walls and windows, solar and internal loads comprising people, equipment, lights, etc.

When Adamus studied DADANCO's technology it became clear that the new system would allow a space gain of 180-250mm per floor, producing an extra floor for every 12 constructed.

Toga produced new plans for the building, incorporating a DADANCO Starline system, and construction is currently under way. The DADANCO Starline system is on display at the Sydney Air conditioning, Refrigeration and Building Services exhibition.

Vladimir Petrovic, DADANCO Managing Director and co-inventor of the new technology, says the heart of their new air conditioning system comprises patented new nozzles which feed primary air from the air conditioning plant to the distribution units, and a re-designed internal profile of the mixing chamber.

"The development of this new technology was really a matter of being in the right place at the right time," Mr Petrovic said.

"A little over three years ago I was working on a PhD project with Professor Sam Luxton at the University of Adelaide when the University management came to us with a problem that needed to be urgently addressed.

"A 13-floor office building owned by the University was being vacated by government tenants because of new regulations concerning air conditioning temperature and noise and, as Sam Luxton was the Professor of Mechanical Engineering at the Uni, the job to find a solution came to him.

"We conducted experiments and from these developed a nozzle design that significantly increased airflow through the induction heat exchanger and dramatically lowered noise levels," Mr Petrovic said.

"We also re-designed the mixing chamber to reduce pressure in the chamber, further increasing the unit's efficiency. This combination of new technology effectively increased airflow through the local heat exchanger in the room induction units by 70% for the same primary airflow through the nozzles," Mr Petrovic said.

"A collateral benefit of altering the nozzle/chamber shape is that it also allows a reduction in primary air pressure from the main plant, which means smaller ducting can be used to achieve the same or, in some cases, even better results with induction systems than other air conditioning systems.

"As has been demonstrated with 117 York Street, DADANCO's compact design means the ceiling space on new buildings can be reduced to 350mm, lowering the slab-to-slab height without reducing floor-to-ceiling height," he said.

"An architect designing an office building or hospital which incorporated our Starline system could effectively add an extra floor for every 12 planned.

"That has significant profitability implications in the property management market, not only in smaller buildings like 117 York Street, but in taller buildings where rent return has to offset enormous construction costs," Mr Petrovic said.

"In the case of a hospital it obviously means you can increase the number of wards and beds."

"After looking at the artist's impression of the proposed 113-floor Grollo Tower, in Melbourne, I could confidently say that if they used our air conditioning technology they could add three extra floors in the lower office part of the tower without increasing the building height.

"However, if we assumed that the Grollo Tower was to be an office building of 113 floors, we can add around 12 more floors for the same height. Also we could dramatically reduce air conditioning maintenance and running costs, and save a floor or two on the air conditioning plant room space," he said.

Mr Petrovic said despite smaller ducting, the Starline system produced the same, if not better, air conditioning efficiency as any other air conditioning system but with more flexibility. "Every office and meeting room on every floor served with Starline units will have the ability to adjust room temperature to individual needs," he said.

"A Starline induction system will not only comply with current building noise and ventilation requirements it will, in most cases, exceed them while offering spin offs like lower maintenance, lower operating costs and reduced environmental impact.

"But, in the case of the York Street project, the main payback for the developer was the gain of the extra floor," Mr Petrovic said.

Technology utilised by DADANCO has been recognised worldwide in the scientific community, and has had successful patent applications granted.