The Thermal Transfer Products EK series (i.e. green cooler) is a high-efficiency heat exchange product in the water-cooled product series. For the product, the surface of the aluminum finned tube bundle is increased so that the optimal heat exchange effect can be achieved at a low water flow rate, and the seawater service options are also available. The low cost and compact structure effectively reduce the occupied area, ensuring that the product is particularly suitable for use in the hydraulic power unit with high requirements for the efficiency, economy and adaptability of cooling equipment.