I've seen products on the market like this, around 800-5000 BTU
Was wondering if I could devise my own as a little project to keep my room (or part of it, near my bed) a few degrees cooler

Thinking cheap water loop with no-name pump, 2x120mm rad and Yate Loons on hot side

Cold side not really sure? I know waterblocks can transfer heat from heat source to water, probably not too efficient at doing the opposite?