19 June 2013 — LETTER: I just noticed the news that Sydney has dropped its trigeneration plans.
Last year I was invited to speak at the Asia Pacific District Cooling Forum. I was also asked to find other speakers and I invited a representative of the City of Sydney to come with me to speak on the Sydney trigeneration project. Nobody could come so I thought to say a few words about it myself to give Sydney a plug.
When I sat down to consider the Sydney proposal, it soon became clear to me that the Sydney plan was fatally flawed. I then set down and tried to find a solution.
The solution lies in existing technology called combined cycle generation. The novelty consists in the fact that I have added a heat pump to condense the steam from the second-stage steam turbine. Thus a great feature of the system is that it would make water and not need any cooling water. Also, it would not be necessary to reticulate any hot water through the city to provide heat for low coefficient of performance (about 0.5) absorption cooling and avoid installation of all the absorption systems at individual buildings.
We would simply supply a lot more electricity for the same fuel consumption, thereby reducing emissions very significantly. We would drive chiller sets to provide cooling with the extra electrical energy at COPs of three to four, which is six to eight times more efficient than absorption cooling.
If we then set about retrofitting CO2 or ammonia systems to existing buildings, we would reduce the emissions even further as these total energy systems are much more efficient the present HFC chiller sets with cooling towers.
If Sydney were to implement both schemes over time, Sydney would be the cleanest city in the world in terms of the lowest emissions, and energy and water consumption per square metre of city office building.