The influence of different ground surface boundary conditions on the efficiency of a single earth-to-air heat exchanger as well as of a multiple parallel earth tubes system has been investigated The cooling potential of both these systems buried under bare soil has been assessed and compared with the cooling potential of the same systems buried under short-grass covered soil. The results revealed that soil surface could be a controllable factor for the improvement of the performance of earth-to-air heat exchangers. The cooling system consists of a single tube or multiple tubes, buried in the ground and through which ambient or indoor air is circulated and cooled : it is then mixed with the indoor air of a building or an agricultural greenhouse. An accurate numerical model has been used to assess the dynamic thermal performances and operational limits of the earth-to-air heat exchangers. Finally, a sensitivity investigation was carried out in order to evaluate the effect of the main design parameters on the system’s cooling capacity. Cumulative frequency distributions of the air temperature at the pipe’s exit have been developed as a function of the input parameters.