Heat transfer of ground heat exchanger for GSHP（4）：system characteristics in coupled operation

By means of numerical simulation and analytical solution, studies the transient heat transfer characteristics of coupled operation of single U-type ground heat exchanger and the overground unit with variable heat flow boundary in summer based on a coupled model. Analyses the variety patterns of COP of GSHP unit, heat exchanger capacity per unit pipe length, inlet and outlet fluid temperature of buried pipe and averaged borehole wall temperature separately in continuous running and intermittent running.