TEST RESULTS FROM THE 500 kW DIRECT CONTACT PILOT PLANT AT EAST MESA

A 500 kW power plant utilizing direct contact heat exchange (DCHX) between the geothermal brine and the isobutane (IC/sub 4/) 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 pilot plant is to determine the feasibility of large-scale direct-contact heat exchange and power plant operation 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 to 400/sup 0/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 in January 1980. The results of these tests and follow-on testing are covered.