Slovakian City Uses Waste-to-Energy System for Heating

August 11, 2014 By Linda Hardesty

ElectraTherm energy manageElectraTherm commissioned 10 Green Machine 4400s for the city of Levice, Slovakia in June 2014.

ElectraTherm’s Czech distributor, GB Consulting, facilitated the deployment of organic rankine cycle (ORC) systems on a centralized district heating system in Slovakia as a means of increasing on-site efficiency and generating clean energy. To date, the site has accumulated over 12,000 hours.

ElectraTherm’s Green Machine generates emission-free power from low temperature waste heat. The 10-machine installation utilizes the waste heat from two Rolls Royce gas turbines through a combined cycle. Exhaust from the turbines goes through a heat recovery steam generator, and lower temperature exhaust gas that cannot be utilized produces hot water to meet demand for heating on the municipality’s district heating system. The remaining heat runs through ElectraTherm’s Green Machines to generate clean energy and attain feed-in-tariff incentives.

Hot water enters the Green Machine at between 170-240°F, where it heats a working fluid into pressurized vapor, using ORC and proprietary technologies. As the vapor expands, it drives ElectraTherm’s patented twin-screw power block, which spins an electric generator and produces power. Run in parallel, the Green Machines in Levice generates about 500 kW.

While combined cycle gas turbines are widely used throughout Europe for power generation and district heating, this is the first application of its kind to utilize ElectraTherm’s ORC technology for the lower temperature waste heat, says the company.

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