"(마음/생각이) 굴뚝같다" (adjective) - be craving or yearning for something very much.
It's a very common everyday expression describing how you crave something acutely (usually a natural desire).
굴뚝 means chimney, so it comes from 굴뚝과 같다(is like a chimney).
So you're craving something the way a chimney so readily sucks up the smoke.
1)- 여행 가고 싶은데 돈이 없다. (I want to travel but I don't have money)
2)- 여행 가고 싶은 마음은 굴뚝같은데 돈이 없다 (I crave to travel so much but I don't have money)
The Naver dictionary has these examples:
며칠을 굶었더니 밥 생각이 굴뚝같다 - I starved a few days and I'm now dying for a meal.
마음은 굴뚝같지만 몸이 말을 듣지 않는다 - My mind wants it so much but my body can't do what I want.