Multifactor analysis on beach well infiltration intake system for seawater source heat pump

The seawater source heat pump (SWHP) is a renewable energy utilization system. The beach well infiltration intake system (BWIS) effectively improves the stability, reliability, and energy efficiency of SWHP systems in cold climate areas. BWIS research requires a multidisciplinary approach that involves both hydrogeology and heat transfer theory. There are many factors influencing the energy consumption and life-cycle costs of the systems, with each factor having many possible values. This paper aims to determine the degree of influence of ten representative factors of BWIS: specific heat capacity of rock-soil, rock-soil density, thermal conductivity of rock-soil, void fraction of rock-soil, rock-soil permeability, beach well radius, site length, site width, row number of beach wells, and column number of beach wells. In this paper, a BWIS seepage and heat transfer model is established. Based on the model, an orthogonal design optimization method is presented and analyses are conducted for heat pump unit energy consumption, seawater pump energy consumption, and economic cost for various conditions using MATLAB code. The results indicate that a greater number of beach wells is not always better and the number and placement of beach wells should be scientifically and objectively optimized by the orthogonal design method. The optimization method can scientifically guide engineering design for BWIS and offset the design deficiency that results from the current practice of only using a hydrogeological report of randomly selected test wells.