Inside Capgemini's free-cooled datacentre

The facility is currently certified to Impact Level 3, a government-set security standard for facilities that store data. This requires a huge level of perimeter security. At Merlin, when modules or equipment are brought inside the facility, they are unloaded into a cage (pictured), where they are screened prior to installation.

The electrical equipment, fire systems and associated IT infrastructure at Merlin (pictured at top) are carried 18 feet above ground level. This was part of Capgemini's strategy for minimising the carbon expended during construction of the facility, according to Anderson.

By not placing the support infrastructure underneath an artificial floor, it is easier for Capgemini to install new modules and to maintain existing equipment, he said.

This ventilation grill is where waste heat from the modules is ejected. "When we had these up at load testing, you could fry a chicken in here. The air came out at 47 degrees Celsius," Anderson said.

The method used in the datacentre for cooling and recycling the air is a five-stage process. The air first passes through a filter, then a set of filter bags, a direct-expansion chilling system, an adiabatic pre-evaporative cooling system (pictured) and finally a series of fans. The direct-expansion chilling is not powered by default, but the electricity kicks in if the ambient air temperature is registered as too high. Adiabatic cooling works by drawing the air through a filter, which is cooled by water. This helps to dissipate the heat and prevent evaporation.

Under full load, the air can rush through the cooling chambers at a pressure of almost 300 pounds per square inch.

To maximise the efficiency of free air cooling in the datacentre, unused racks are carefully sealed to maintain pressure and eliminate undesired airflow.

Here is where power is supplied to the racks. Each fully-loaded module can draw down a maximum power load of 232kW.

The facility is currently being certified by the Uptime Institute as a Tier 3 facility. This requires the facility to have multiple redundant capacity components and multiple distribution paths serving the computer equipment, hence the two separate power cables.