| Title | Field Performance Evaluation of an Organic Rankine Cycle at a Geothermal Power Plant |
|---|---|
| Authors | Rodrigo ALARCÓN, Héctor AVIÑA, Oscar DE SANTIAGO, Pedro DOMÃNGUEZ, Uriel RUSSELL |
| Year | 2020 |
| Conference | World Geothermal Congress |
| Keywords | Binary cycle, low-enthalpy, microturbine, power generation, Organic Rankine Cycle, field performance |
| Abstract | Organic Rankine Cycles are positioned as an attractive alternative for on-site electric microgeneration due to their ability to take advantage of low-quality energy sources such as waste heat from industrial activities or renewable energy resources, for instance solar, biomass and low-enthalpy geothermal energy. The increase on the worldwide ORC installed capacity, especially in the last decade, shows the great impact these systems have in the economy of industrial sector, granting environmental and monetary benefits for the reduction of fossil fuels, even in the electrical sector they are considered as a source of backup and load regulation during peak demand hours using low temperature geothermal energy in a cost-effective manner. This paper sets out the evaluation procedure for a 2 kW Organic Rankine Cycle operated with geothermal resources at pressure and temperature conditions of 8.5 bar (125 psig) and 170 Celsius degrees (338°F), respectively. The energy source is a regulating station at Domo de San Pedro Geothermal Power Field in Mexico. This case study considers an ORC with two radial outflow turbines using R245fa as working fluid and a wet cooling tower for refrigerant condensing. Performance tests include operation of the cycle away from its design range settings, and which are conducted in order to determine the response of the condensing elements, and how the operation in dynamically, thermally-unbalanced conditions affects the stability of other components, such as the turbines, the feed pump and the storage tank. The work describes the test procedures and measurement methods used to obtain the response of each component and a comparison between theoretical design parameters of the heat source and the real ones found on the site. The paper includes operational alternatives whose results lead to obtaining better equipment and the implementation of best practices to evaluate the performance of these components in a Geothermal Power Plant. |