Does anyone use this amazing apparatus?
I'm wondering if you can pour cold water in it and get a hot espresso (which, well, should be hot by definition)? If so, how does the heat come about?
Well according to the video presented on the website you have to provide hot water.
To my understanding of the machine's principle as well as physics there is absolutely no way it could produce hot coffee from cold water. The confusing quote from the FAQ
Minipresso produces at ambient condition (75°F, 24°C), an espresso at perfect temperature (152°F, 67°C in cup) with a nice compact and persistent crema on top.
actually is about temperature loss during the process.