Studying and investigating the feasibility of utilizing buried condensers in steam power plants

Conventional steam power plants reject a substantial fraction of their thermal energy through condenser systems, while this low-grade waste heat remains largely unutilized. This study proposes and evaluates a novel integrated concept in which buried condenser pipelines simultaneously function as a condenser cooling system and a seasonal thermal energy storage (STES) medium by storing rejected heat within the surrounding soil for subsequent winter recovery. A transient three-dimensional numerical model based on the finite-volume method was developed and implemented in ANSYS Fluent to simulate coupled heat transfer between condenser discharge pipes and the surrounding ground under realistic operating conditions of the 370 MW Tabriz steam power plant. The model incorporates actual plant operating data, local soil thermophysical properties, and practical engineering constraints, including burial depth, pipe diameter, and pipe spacing. Numerical predictions were validated against established analytical solutions and published benchmark studies, demonstrating good agreement with relative errors below 4.2%. The simulations indicate that a burial depth of 1 m, a pipe diameter of 250 mm, and a minimum pipe spacing of 3 m provide the most favorable compromise between heat transfer efficiency and thermal interference. The surrounding soil progressively accumulates thermal energy during prolonged operation, creating a stable underground thermal reservoir capable of supplying useful heat during colder seasons. The results further demonstrate that appropriate geometric optimization significantly enhances heat recovery potential while maintaining practical installation requirements. The principal novelty of this work lies in introducing buried condenser pipelines as a dual-function infrastructure that combines condenser heat rejection with large-scale seasonal thermal energy storage, rather than treating underground piping solely as a cooling mechanism. Unlike previous investigations that focused primarily on underground heat exchangers or geothermal applications, the present study develops a practical engineering framework specifically for recovering waste heat from steam power plant condensers and integrating it with future district-heating and agricultural heating systems. The proposed methodology provides a scalable design framework for improving overall power-plant energy utilization, reducing thermal pollution, and facilitating the integration of waste-heat recovery technologies into sustainable energy systems. The findings establish a foundation for future techno-economic optimization, hybrid renewable energy integration, and large-scale seasonal heat storage applications in thermal power plants operating under similar climatic conditions.