Traditionally the heat exchangers that are commonly used in energy field are bulky and not very efficient, while for some applications the degree of compactness, intended as the exchange surface over the total volume, is a fundamental aspect like in offshore oil and gas applications. Therefore, a very compact but extremely reliable device is the best option. A device able to satisfy these characteristics it’s called Printed Circuit Heat Exchanger (PCHE), it is able to reach compactness ratio of around 1100 m^2/m^3 and, even if composed by plates stacked, thanks to the diffusion bonding process it has the same properties of a monolithic.