Kyle R., Mark L., Mark D., Ken D., Richard M. and Jacob (MCE)

The initial 20kW duct heater used to supply heated air to the CP4 bake enclosure has proven insufficient to heat CP4, GV11 and GV12 to the desired 130C setpoint. As such, we shut down heating this morning to allow the installation of an additional 10kW duct heater.  The current setup uses an independent squirrel cage fan to circulate air within the insulated bake enclosure, the newly installed 10kW duct heater (on/off operation, shares AC source but not PLC controlled) and the initial 20kW duct heater (PID/PLC controlled).  Should the addition of this second duct heater still not be enough, we may choose to utilize the CP4's regeneration circuit as an alternative means to supply more Joules to the bake effort.  This setup vaporizes liquid nitrogen (stored in large tanks (dewars) outside of the building and nominally used for the cryogenic pumps) using ambient heat absorbed in a heat exchanger then further heats this gas to the desired temperature via electric heating element.  This heated GN2 then flows through the inner vessel (nominally filled with LN2) located within CP4 vacuum chamber before exiting to atmosphere via an exhaust line. 

We will allow the duct heaters to reach maximum output over the weekend before experimenting with the regeneration circuit.