Technology Steam Tubine Recip. Engine Gas turbine Microturbine Fuel Cell Pwer Efficiency(HHV) 15 - 38%22-40%22-63%18-27%30-63% Overall Efficiency (HHV)80%70-80%70-75%65-75%55-80% Effective electrical efficiency75%70-80%50-70% 55-80% Typical capacity (Mwe)0.5-2500.01-50.5-250 0.03- 0.250.005-2 Typical power to heat ratio0.1-0.30.5-10.5-20.4-0.71.0-2 Part-loadok poorokgood CHP Installed cost ($/kWhe) 430- 11001100-2200 970-1300 (5-40 MW)2400-30005000-6500 O&M costs($kWe)<0.0050.009-0.0220.004-0.0110.012-0.0250.032-0.038 Availability near 100%92-97%90-98% >95% Hours to overauls >50.00 025000-50000 20000-4000032000-64000 Start up time 1hr- 1day10 sec10min-1hr60 sec3hrs - 2days Fuel Pressure (psig)n/a1.0-45 100- 500(compressor ) 50- 80(compressor)0.5-45 Fuelsall Natural gas, biogass, natural gas, biogas natural gas, biogass, hydrogen, natural gas, propane, landfill gas propane,oil propane, methanol Noisehigh modera te low Uses for thermal outputlp-HP STEAM hot water, LP stream heat,hotwater,LP-HP steam hotwater,LP-HP steam Powere Density (kW/m^2)>10035-500.036-0.050.015-0.0360.0025-.0040 Nox(ldMMBtu)(not includ SCR) GAS.1-.2 0.013 rich burn 3-way cat. 0.17 lean burn0.036-.0.050.015-0.0360.0025-.0040 Wood 0.2-.5 Coal 0.3-1.2 lb/MWh (not including SCR)GAS0.4-0.8 0.06 rich burn 3 way cat. 0.8 lean burn 0.17- 0.25 0.08- 0.020.011-0.016 Wood0.9-1.4 Coal 1.2-5.0 Combined Heat and Power (CHP) Technology Eduardo Cristi Masato R. Nakamura Department of Mechanical Engineering and Industrial Design Technology, New York City College of Technology (Citytech) City University of New York (CUNY), Brooklyn, NY Background Methodology Objectives Summary and future work Typical Cost and Performance Characteristics System Component Efficiency Measure Description Separate Heat and power(SHP)Thermal Efficiency(Boiler)EFFq=Net useful thermal output/Energy Input Net Useful thermal energy output for the fuel consumed Electric Only GenerationEFFp=Power Output/Energy input Electricity Purchased From Central Stations Via Transmission Grid Overall Efficiency of Separate Heat andEFFshp=(P+Q)/(p/EFFp)+(Q/EFFt) Sum of net power(P) and useful thermal energy output (Q) divided by Power(SHP) the sum of fuel consumed to produce each Combined Heat And PowerTotal CHP System EfficiencyEFFferc=(P+Q/2)/F Sum of the net power and net useful thermal ouptu divided by the total fuel (F) consumed FERFC Efficiency StandardEFFferc= (p+Q/2)/F Developed For the Public Utilitis Regulatory Act of 1978, the FERC methodologyattempts to recognize the quality of electrical output relative to thermal output Effective Electical Efficiency (or Fuel Utilization Efficiency, FUE)FUE=p/(F-Q/EFFt) Ratio of Net Power output to net fuel consummption, where net fuel Consumption excludes the portion offuel udes for producing useful heat output. Fuel used to produce useful heat is calculated assuming typical boiler efficiency, usually 80 percent Percent Fuel SavingsS=1-f/(P/EFFp)+(Q/EFFq) Fuel savings compared the fuel used by the CHP system to a separate heat and power system.Positive values represent fuel savings while negative values indicate that the CHP system is using more fuel than SHP Key: P= Net power output from CHP system Q=Net useful Thermal Energy from CHP system F=-Total fuel input to CHP EFFp=Efficiency of displaced electric generation EFFq= Efficieny of displaced thermal generation Tempetute Classification Waste Heat Source Characteristics Commercial waste Heat to Power Technologiea High (>1200)Furnaceshigh quality heatWaste heat boilers and Steam Turbines steel elcetric arcHigh heat transfer steel heating high power geration efficiencies basic oxygenchemical and mechanical contaminants aluminum reverberatory copper reverberatory nickel refining copper refining glass melting iron cupolas coke ovens Fume incenerators Hydrogen Plants Medium(500-1200)Prime mover exhaust streamsMedium Power Generation Efficiences Waste heat boilers and steam turbines(>500f) gas turbineChemical And Mechanical ContaminantsOrganic Rankine cycle (<800F) Reciprocating engineKalina Cyle(<1000F) Heat-Treating furnaces ovens Drying Baking Curing Cement Kilns Low(<500 )BoilersEnergy contained in numerous small Organc Rankin cycle (>300F Gaseous streams, >175F liquid streams) Ethylene FurnacessourcesKalina Cycle(>200F) Steam condensateRecovery of combustion streams limited cooling water due to acid concentration if tempeture furnace doors reduced below 250F annealing furnaces Low power generation efficiencies air compressors ic engine refrigeration condensors low tempeture ovens hot process liquids or solids Very Low (<200F)SMA Engine (70C) Seebeck effect (500K) Stirling Engine (35- 50) Waste Heat Streams Classified By Temperature Efficiency of CHP Systems Combined Heat and Power technology is a system that combines two processes into one. Typically there are coal powered plants that have the sole purpose of creating electricity by heating water and running it though an engine that powers a generator. There are also plants who’s sole purpose is to that heat water for urban areas. A CHP system combines these two plants so that when a plant heats water to go to an urban area it runs the water through some sort of engine. This drastically increases the efficiency of the plant. This allows to use more fuel the one plant but outputs just as much as both of the plants. CHP systems are defined by what time of engine produces electricity such as a turbine or reciprocating engine. But there are several other components that make up a CHP system such as prime mover, generator, heat recovery system, electrical interconnection equipment configured into a integrated system.
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