The data centre industry is immersed in an interesting innovation process in search of higher efficiencies.

One idea is using trigeneration, where electricity is generated (via engine or turbine) and its residual heat is used as a heat source for an absorption chiller. For example, a car engine provides mechanical energy to move the car and waste heat for heating (radiator). Trigeneration systems tend to be more expensive and complex than traditional systems, but are able to save energy providing the waste heat is utilised all year round.

A simplistic analysis is that a data centre always requires electrical energy and refrigeration, therefore trigeneration is an ideal application.

However, when this is examined in more detail some problems are uncovered. Whilst we may need to
cool IT equipment, this does not always require refrigeration (chillers), as there are many free cooling (FC) solutions available. The following table summarises these requirements and features (UK typical values).



Free cooling without chillers is the most interesting cost-effective option with lowest CO2 emissions.

In order to maximise free cooling potential we need good air management (including physical
containment of hot and cold air streams) and increase the supply air temperature from around 12°C to 20°C and higher. Whilst this is technically achievable, we also need to eliminate the logical apprehension of paradigm change.