Nope, to reclaim energy you need a temperature difference. If you want that difference, best bet is to use a radiator with a cooling fan. Inserting a device between your heat source and your heat sink will decrease transfer of heat.
for the same size of cooling fan + device. You can always increase the fan if it means you're also going to recover some energy.
I don't see why this wouldn't work tbh. Say your CPU is hot and the room is cold. The desire end state is that the CPU will reach room temperature, with the room being warmed up a little (let's not talk about getting the energy out of the room). There is no alternative to this end state.
To reach the end state, you can dissipate the heat of the CPU in the room "as simply as possible", OR you could transform some of it to electricity, and use the electricity to power some other device, say a desk lamp, and heat the room that way.