Continuous duty gen-sets provide base-load power generation in diverse applications around the globe. However, high fuel costs and engine maintenance are pain points felt by operators. A low-maintenance path to significant fuel savings and lower emissions is what the U.S. Department of Defense (DOD) had in mind when they approached ElectraTherm to integrate the company’s Green Machine waste heat to power (WHP) generator with a 1.1 MW Cummins KTA-50 generator. ElectraTherm specializes in smallscale, distributed power generation from waste heat, utilizing Organic Rankine Cycle (ORC) and proprietary technologies to generate power from low temperature heat ranging from 77o to 116°C. The company’s WHP technology converts various sources of heat into power, including internal combustion engines, small geothermal, biomass, concentrated solar and process heat. To date, ElectraTherm said it has deployed 42 units worldwide, with a cumulative 250 000 operating hours and over 97% availability.
ElectraTherm’s primary market is waste heat from stationary internal combustion engines. Typical sites for these engines include prime power production in remote areas, island and developing nations, biogas gensets including landfill and waste water treatment plants, natural gas compression stations and renewable biofuels. With the typical engine running at about 35% efficiency, there is considerable waste heat between the jacket water and the exhaust that ElectraTherm converts into emissions-free/fuel-free electricity.
ElectraTherm’s Green Machine generator operates using a closed-loop ORC, where hot water is the fuel. Hot water from the engine enters a heat exchanger to excite (pressurize) the nonflammable, nontoxic working fluid, driving the twin-screw expander and generator to create electricity. The company said its twin-screw expander is unique in its configuration, lubrication and specifications, but the core technology is based on decades of proven compressor technology.