<p>Ocean thermal energy conversion (OTEC) offers stable electricity generation owing to its low variability compared with other ocean energy sources. However, its efficiency remains limited by the small temperature difference between surface and deep seawater. To address this, we investigated the use of a high-temperature waste heat source as an alternative surface heat source. For demonstration, a 200-kW closed-circuit high-temperature power generation plant was designed and built using R245fa as the working fluid, with a heat source of 75 ℃ and a heat sink of 5 ℃. Based on this experimental model, a dynamic analysis model of a 178-kW high-temperature difference power plant with an efficiency of 7.71% was obtained. The results demonstrate the critical role of heat source temperature in OTEC efficiency, showing that higher heat source temperatures directly and predictably improve output, efficiency, and power. This study provides valuable experimental data to advance the practical application of OTEC systems using waste heat and deep seawater.</p>