Another important element of the test cell HVAC system is the exhaust extract system. This has to deal with hot and contaminated air, with residual elements of fuel. The challenges are to not influence the performance of the engine by adding an extract system.
Our design provides a drawn outlet into which the vehicle exhaust system is fed, to cool the exhaust gases somewhat additional dilution air is drawn from the test cell and mixes with the exhaust gas prior to it reaching the high temperature fan.
Typical ratios are 5:1 dilution to exhaust gas. The diluted air mix is passed through a silencer before reaching the fan and being blown out of the building using a jat cowl to project the fumes away from the building.
The extract system will be fitted with fire dampers at test cell penetrations.
The high temperature extract fans are inverter driven for added control.