I guess this is about the battle of Ningpo (there is no mention of tigers on the Wikipedia article)

https://en.wikipedia.org/wiki/Battle_of_Ningpo

It has been a serious subject in engineering for decades, it’s only becoming more common because heat is becoming more expensive and polygeneration can now be used as for marketing

And how do you cool it in summer, when people don’t need as much heat?

It’s much more complicated than it seems