This is where the control system asks for heating from Boilers or cooling from Chillers. In principle this is quite simple and most control systems do it.
In practice many control systems will keep the boilers and chillers on most of the time during office hours. Typical causes are:
- A single miscalibrated temperature sensor in a building with hundreds of sensors.
- A single room with an aircon fault.
- A room where the temperature is set too high or low.
Demand led operation should ask for boilers or chillers when needed. On a summers day boilers should not be required.
A well managed ‘Demand Led’ building will use boilers in midwinter, chillers in midsummer and on temperate days boilers may be required in the morning with chillers in the afternoon. There are some cases where boilers and chillers are required at the same time…for instance sunny days in winter.
Well managed Demand Led systems are very cost efficient. The energy savings can outweigh the cost of implementation.