ElectraTherm’s Power+ Generator converts waste heat from engines into clean electricity at biogas facility.
Biogas/Heat-to-Power Application on Two MWM Internal Combustion Engines
Site: Brno, Czech Rep.
Engine Max Power: 980kWe (currently limited to 900 kWe)
Power+ Generator Gross Power Output Avg: 32-39 kWe
Thermal Input to the Power+ Generator: 375-500kWt
Hot Water Input Range: 86 – 92°C
Hot Water Flow: 35 m3/hour
Ambient Temperature: 0-25°C
Date Commissioned: Q2 2012
ElectraTherm’s Power+ generates fuel-free, emission free power from low temperature waste heat. In the Czech Republic, ElectraTherm’s Eastern European distributor, GB Consulting, commissioned the machine in February at a biogas plant to generate additional power and increase energy efficiency on site. To date, the machine has maintained over 95% uptime.
The Power+ was added to an existing biogas power facility producing 900kWe. The two MWM internal combustion engines are equipped with an exhaust gas heat exchanger designed to combine both the heat available in the exhaust and the heat available in the jacket water into a single heat stream. The waste heat from the engines is used to heat the anaerobic digestion process, and excess heat not needed to sustain the anaerobic digestion process is utilized by the Power+ to produce fossil-fuel free electricity 24/7.
The anaerobic digestion process at this site uses a corn silage and manure slurry/mixture as the fuel source. The corn and manure are loaded into a self-feeding hopper. From the hopper, the resulting biomass is pumped to the digester, where methane is produced through anaerobic digestion. The methane in turn fuels the engines. With the addition of the Power+, excess heat is used to generate approximately 5% more electricity and reduces the electricity needed to reject this excess heat through radiator fans. This lowers the customer’s onsite power demands and improves site economics.
ElectraTherm uses Organic Rankine Cycle and patented technologies to generate electricity from waste heat. The process begins with hot water entering the Power+ at 86-92°C, where it heats a working fluid into a pressurized vapor. The high pressure vapor expands through ElectraTherm’s patented twin screw power block, spinning an electric generator rated for up to 50kWe output. After turning the expander, the vapor is condensed back into a liquid through the use of an external air cooled condenser. After condensing, the working fluid flows back to the evaporator to repeat the process.