PhD Defence at DTU Mechanical Engineering

PhD Defence 8th December: Numerical Evaluation of the Kalina Cycle for Concentrating Solar Power Plants

Wednesday 02 Dec 15

Anish Modi from DTU Mechanical Engineering defends his PhD "Numerical Evaluation of the Kalina Cycle for Concentrating Solar Power Plants" Tuesday, 8th December 2015, at 14:00. The defence takes place at the Technical University of Denmark, Building 421, Auditorium 71. Professor Fredrik Haglind is supervisor.

Concentrating solar power plants use a number of reflecting mirrors to focus and convert the incident solar energy to heat, and a power cycle to convert this heat into electricity. One of the key challenges currently faced by the solar industry is the high cost of electricity production. These costs can be driven down by developing more cost-effective plant components and improving the system designs. This thesis focuses on the power cycle aspect of the concentrating solar power plants by studying the use a Kalina cycle with ammonia-water mixtures as the cycle working fluid. The potential of using a Kalina cycle is evaluated with a thermoeconomic optimization with a turbine inlet temperature of 500 C for a central receiver solar power plant with direct vapour generation, and 370 C for a parabolic trough solar power plant with Therminol VP-1 as the solar field heat transfer fluid. No thermal storage is considered in this study.

A general methodology is presented to solve the high temperature Kalina cycle at both the design and the part-load conditions. Using this methodology, the plant was optimized by minimizing the levelized cost of electricity considering (1) the operation parameters from the Kalina cycle and the solar field design, (2) the part-load performances of both the Kalina cycle and the respective solar fields, and (3) the cost functions to estimate the Capital investment and the operations and maintenance costs.

The results from this study indicate that the Kalina cycle has a higher specific Capital investment cost and a higher levelized cost of electricity than the state-of-the-art steam Rankine cycle for both the central receiver and the parabolic trough plants. This is mainly because of worse power cycle design point efficiency than the corresponding steam Rankine cycle configuration and the higher capital investment cost of the power cycle itself. This causes the levelized cost of electricity for nearly all the considered Kalina cycle cases to be outside the range of the values for contemporary concentrating solar power plants. Therefore when considering both the thermodynamic and the economic perspectives, the results suggest that it is not beneficial to use the Kalina cycle for high temperature concentrating solar power plants.

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16 JANUARY 2021