Test Results from the 500 kW Direct Contact Pilot Plant at East Mesa

Abstract

A 500 KW power plant utilizing a direct contact heat exchange (DCHX) between the geothermal brine and the isobutane working fluid is being operated at the East Mesa test facility. The power plant incorporates a 40 inch diameter direct contactor approximately 35 feet tall. The purpose of the point plant is to determine the feasability of large scale direct contact heat exhange and power plant operations with the DCHX. The binary cycle offers higher conversion factors (heat energy transformed to electrical energy) than the flashed steam approach for geothermal brines in the 300°F to 400°F range and preliminary results indicate the DCHX system may have higher performance than the conventional tube and shell binary approach. This performance advantage results from the absence of any fouling and the very close pinch temperatures achieved in the DCHX itself. The baseline performance tests for the plant were completed January, 1980. The results of the test and follow on testing are covered in this summary.