Air-conditioning for tall buildings can be a challenge for a number of reasons.
- As you build taller you have to contend with variance in ambient temperature and wind which is a particular issue when you exceed 60 storeys
- With air-conditioning typically accounting for 30 per cent of a building’s energy consumption, by simple virtue of their size, tall buildings use a lot of energy
- With saleable floor space being crucial for development business cases to stack up, developers don’t want large areas of plant wasting space, yet buyers won’t accept anything but the best internal environment
If you look at how high-rise apartment living has developed over the years, while heating systems would be included historically air-conditioning was not a standard fixture. As our climate has started to change and the demands of building users have increased, the expectation is for both heating and cooling. This is far more efficient to do as a single system.
Traditionally, there have been three main approaches:
- A central four pipe water system which consists of air cooled chillers and boilers to serve indoor fan coil units located within each apartment
- A central water cooled system which consists of cooling towers and boilers to serve water sourced heat pumps fan coil units located within each unit
- Split air cooled air conditioners with outdoor condensers mounted on the balcony of each unit.
And now there are two alternatives beginning to change the way we look at air-conditioning solutions for tall buildings
- Variable Refrigerant Flow air conditioning units are effectively a central air cooled outdoor condenser units serving multiple indoor air conditioning units.
- The other system which is a hybrid system consisting of closed circuit cooler connected to water cooled variable refrigerant condenser units serving multiple indoor air conditioning units.
So what are the pros and cons of all these systems and what benefits can we derive for both clients and end-users?