energy storage model (joule unit)

Hello sir

I have a simple 2D model which has energy storage in the middle of model.
I want to see how temperature profile changes with time.

To simulate my model, I need to 1000J(joule) in storage model.
But in COMSOL, the options are always W(watt).

How can I use energy storage about joule unit in COMSOL?

please help.