Abstract:
Organic Rankine Cycle (ORC) is one alternative to answer the question of energy conservation in industrial section, since it uses working fluid with low boiling point, and it can be used with waste heat in industrial section with low temperature. However, the cycle design is complicated, due to many variables affecting the turbine work, the thermal efficiency of the system and the decision-making to invest in the project economically.
This thesis had the objectives to develop the mathematical model to assist in analyzing the properties of the working fluid R-245fa and to develop program for analyzing the Organic Rankine Cycle, both in the cycle design and the economics of the energy investment on the thermodynamic basis of the cycle. It also included the factor analysis of the temperature values and the pressure of the working fluid before entering the turbine, which affects the total efficiency of the cycle, and the economic analysis which affects the internal rate return (IRR), Levelized Electricity Cost (LEC) and the time duration of the project break-even point.
The thesis result found that the developed mathematical model to analyze the relationship of the working fluid with the Coefficient of determination (R2) between 0.98-1 The researcher used this model in the development of the program for Organic Rankine Cycle analysis and found that the errors of this program from the comparison of the data of the experimental result of the researches of Seok Hun Kang and of Byung Sik Park were in total between -5.41-0.64%. Then there was the study of the relationship between the temperature of the waste heat, the pressure of the working fluid before entering the turbine with the amount of the work output, the heat absorbed and the thermal efficiency of the cycle, with the Coefficient of determination (R2) was between 0.98-1. While analyzing the economical factor of the cycle, it was found that the increase of the electricity generation size of the Organic Rankine Cycle or the increase of electricity generation hour annually would affect the capital cost of Levelized Electricity Cost (LEC) to decrease, making the internal rate return (IRR) increase and the time duration of the break-even point shorter. On the contrary, the increase of the interest, the investment cost and the annual management and maintenance would make the capital cost Levelized Electricity Cost (LEC) increase, affecting the IRR to decrease and the program break-even point longer.