Influence Of Main Components On The Solar Chimney Power System Performance

Solar chimney power system (SCPS) is a thermal system that is suitable forlarge-scale power generation. There are vast regions where SCPS has large potentialof application in Western China. On the basis of thermodynamic theory for flow andheat transfer in the solar chimney power plant system, investigation the effects ofcollector radius turbine pressure drop and character of chimney on the performanceof system are made in this dissertation, with some useful results obtained as follows:①The performance comparison between double and single collector solarchimney system indicates that the double collector solar chimney system is betterfor better insulation performance. The reason for power changes with the pressuredrop of turbine and collector radius is the air temperature and air flux changes withthem. And the air temperature distribution in collector is shown for the first time;Air temperature distribution changes with collector radius and pressure drop ofturbine: the first one distribution case is the air temperature rise trend keeps in allprocess and the second distribution case is the air temperature rise trend just in frontbut keeping constant in back process. For the first case, increasing the radius ofcollector is good to power; in the second case, the proportion of constant processlength in entire process indicates the efficiency of collector in a certain extent. As anexample, when irradiation and pressure drop are600W/m2and240Pa, the optimumcollector radius is440m.②The relationship between pressure potential and air flux are different inboth sides of the optimum air flux: When less than optimal air flux, pressurepotential is a line function of air flux, when greater than optimal flow, pressurepotential is a power function of air flux and the relationship between exponent mand optimum turbine pressure drop ratiof optis fopt (2m)/3.The differenceof maximum power and optimum turbine pressure drop ratio obtained by powerfunction and actual value are within3.5%. With the increasing of collector radius,the system power, air temperature rise, storage layer temperature rise showed anincreasing trend while optimum pressure ratio, power per unit and heat flux aretested decreasing trend. With the increasing of turbine pressure drop, the increasesrate of air temperature rise and pressure potential are increase, and led to volumeflow decreases linearly. ③The chimney length and divergent angle have an important influence on theperformance: when the divergent length is constant, the power showing an upwardtrend at first and showing a downward trend after reaching the maximum power withthe rising divergent angle; when the divergent angle is constant, the relationshipbetween power and divergent length is same to the relationship between power anddivergent angle. The optimum length of the divergent and is affected by the angle ofthe divergent. As a case, when collector radius and divergent length are160m and12m the optimal divergent angle is13.5°, when collector radius and divergentlength are160m and44m the optimal divergent angle is9°. The reason for systemperformance changes with divergent length and angle is the expansion capability ofairflow in the chimney, which is the reason for the interaction between the twoparameters.