Utilization of partial through-flow tower shell to cope with the excess cooling capacity of dry cooling tower in extremely cold days with crosswind

Abstract

During low ambient temperature periods, the huge heat transfer temperature difference would result in an excess cooling capacity of the natural draft dry cooling tower. So low cooling water temperature and back pressure can be easily achieved in cold days due to the unavoidable air leakage in practical operation, and the excess cooling capacity is a great threat to the safe operation of the indirect dry cooling system. To cope with that problem, a novel partial through-flow tower shell is proposed. By numerical simulation of the tower, aerodynamic fields in and around the tower were presented, and cooling water temperature drop was exported as well. It was found that thermal performance of the tower would get enhanced by crosswind under the air leakage condition, but that can be counteracted by the proposed partial through-flow tower shell. The through-flow tower shell is effective to reduce air inflow rate and cooling capacity of the tower, and increase back pressure and cooling water temperature after the coupling of the tower and condenser. Compared with the sideward or leeward through-flow tower shell, the windward through-flow tower shell would provide a much larger feasible region for safe operation of the system, and achieve the maximum anti-freezing result at the moderate wind speed. At the fairly high wind speed, the sideward through-flow tower shell would bring the adverse effect, while the other two forms are still active, although their anti-freezing effects degrade a bit in this condition.