Thermal Energy Mixer Unit Attributes

[nrgeng]

The task is to “mix” the energy outlet streams for an Expander Unit and a Compressor Unit. It appears that the Units are not passing TemperatureLow and TemperatureHigh attributes to the Thermal Energy Mixer Unit. I am prevented from entering the temperature attributes for streams 01 and 02, but the Units do not pass them either. Sounds like a Catch 22 situation to me. Can you please help?

The Thermal Energy Mixer Unit energy mixing calculation is correct and the flowsheet solves upon removing the Thermal Energy Mixer Unit. The error message is

failed to solve unit Thermal Energy Mixer-23: not all information on stream 03 was specified

Because of your previous posts, I have learned to check the COCO Help System prior to posting a problem. I found this for the Thermal Energy Mixer Unit:

If any of the temperature limits on the inlets is missing, the outlets will simply contain the minimum and maximum values of the temperature limits on the inlet streams (if all are missing, so are the limits on the outlet stream).

Flowsheet setup:
Thermal Energy Mixer Unit: inlet streams 01 and 02, outlet stream 03.

Last run report from Thermal Energy Mixer Unit:
WARNING: Missing lower temperature for Inlet 1
WARNING: Missing upper temperature for Inlet 1
WARNING: Missing lower temperature for Inlet 2
WARNING: Missing upper temperature for Inlet 2
Not all limits available; ignoring temperature curves

[jasper]

Can you send me the fsd?

[nrgeng]

I e-mailed a flowsheet that exhibits the described problem. Hope you can find a solution.

[jasper]

The thermal energy mixer expects all its ports to be connected to thermal energy streams. In addition to work, they have the range of temperature in which the energy was delivered.

Such energy streams are present on heat exchanging devices, such as a flash with heat input/output, a reactor with heat input/output, a HeaterCooler....

The compressor and expander produce energy, but not thermal energy. This could be electric energy, or energy excerted on a shaft to drive something else... Hence, their energy output streams are not intended to go into the thermal energy mixer.

[nrgeng]

Both the Compressor and the Expander have energy outlet streams. How does one use the provided energy outlet streams, there is no mixer or other Units to connect to is there? If no connections, then what is their purpose?

06/10/2013 COCO Forum

[jasper]

Pump, compressor, expander and turbine can all operate with energy outlet streams or energy inlet streams. It depends on the mode of operation. For example, you can check "Energy defined by energy stream" on the Compressor. Now it no longer has an energy outlet stream, but an energy inlet stream.