Seawater temperature is a critical factor in the design and operation of new energy systems that utilize ocean energy

such as seawater-source heat pumps and power generation systems that use seawater as the cooling medium. In this study

statistical data on the water temperatures in the Yellow Sea and the Bohai Sea near Dalian

China

from 2005 to 2021

were obtained. Thereafter

the daily variation formulas of the annual seawater temperatures were derived

which can provide more reasonable fundamental data for the design and research of ocean energy utilization systems. It was observed that the typical seawater temperatures increased in 2021. The maximum increase in the mean monthly temperature was 0.98 ℃ compared with that in 2014. From 2005 to 2021

the extreme water temperatures in the Yellow Sea were 26.2 °C in the summer and ?0.4 °C in the winter

and the extreme temperatures in the Bohai Sea were 28.6 °C in the summer and ?1.8 °C in the winter. Because the temperatures in the Yellow Sea were lower in the summer and higher in the winter compared with those of the Bohai Sea

the Yellow Sea is more suitable as a heat source for seawater-source heat pumps.