A small-scale prototype of the SCPP was built in the laboratory for investigating the chimney shape impact on the performance of the SCPP (as shown in Fig. 2). A moveable guide wall was added into the prototype initially aimed for reducing the loss caused by the flow direction shifting. As more than suppressing the loss, the guide wall may have further contribution in improving the system potential as reported by Ming et al. [11], the moveable wall provided chances to examine preliminarily the variation in the buoyant flow caused by the GW subset: one additional group of experiments without the GW was conducted for the small-scale prototype and compared with the earlier experiments with the GW. The following sections presented a brief introduction on the configurations of the experiments. More details can be found elsewhere.