Keywords: heat storage, night operation, solar chimney, solar ponds, solar energy, solar power, heat extraction, mathematical modelling, solar radiation, hot brine
Night operation of solar chimney power system using solar ponds for heat storage
An alternative method of heat extraction from salt gradient solar ponds to solar collector is investigated with the aim of night operation for solar chimney power system. Some details of the combined power system integrated with solar ponds and solar chimney power system are also provided. Using a developed mathematical model, theoretical analyses are carried out to investigate the performance of the combined system without considering weak solar radiation effects in the early morning. It is found from steady-state analyses that the combined solar system comprising of a daytime 5 MW solar chimney power plant and solar ponds with proper dimension is able to produce more than 2.21 MW power during night. In addition, the power output for the combined system increases with the temperature of the collector entering hot brine and its mass flow, which is directly proportional to the plastic film height and the brine velocity. It is found from non-steady-state analyses that the combination of the daytime 5 MW solar chimney power plant and 1,400,000 m² solar ponds is a good choice, considering its performance and cost factor. This would make the day before performance of solar ponds be renewed by next day.