What connection method do they use? Most connectors for that purpose would have a pressure rating, so you wouldnt' want to go beyond that.
But generally cooling wouldn't be about higher pressure, rather about higher volume of flow for more cooling.
So you could use a very low pressure setup that has very high volume of flow and a large radiative surface that can get rid of the heat. I suspect that's what's intended.
The higher the pressure you use above atmospheric, the greater the risk of a leak at a seal or connector/tubing interface.