Pipes moving water are cheaper than heat pipes, which are not "solid state", typically heat pipes contain a lot of water in liquid and vapour form under low pressure. If you wanted to move a lot of heat, you would need bigger pipes, which would need to withstand more force, so thicker. It's cheaper to just move that water with pump and if you place your inlet in proper place (higher than your machinery), you could even get some energy from flow of water.