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 efficiency 75% 70-80% 50-70% 50-70% 55-80%

Typical capacity (Mwe) 0.5-250 0.01-5 0.5-2500.03-0.25 0.005-2

Typical power to heat ratio 0.1-0.3 0.5-1 0.5-2 0.4-0.7 1.0-2

Part-load ok ok poor ok good

CHP Installed cost ($/kWhe)430-1100 1100-2200

970-1300 (5-40 MW) 2400-3000 5000-6500

O&M costs($kWe) <0.005 0.009-0.022 0.004-0.011 0.012-0.025 0.032-0.038

Availabilitynear 100% 92-97% 90-98% 90-98% >95%

Hours to overauls>50.000 25000-50000 25000-50000 20000-40000 32000-64000

Start up time1hr-1day 10 sec 10min-1hr 60 sec 3hrs - 2days

Fuel Pressure (psig) n/a 1.0-45

100-500(compressor)

50-80(compressor) 0.5-45

Fuels allNatural gas, biogass,

natural gas, biogas

natural gas, biogass,

hydrogen, natural gas,

 propane, landfill gas  propane,oil  propane,oil

 propane, methanol

Noise high highmoderate

moderate low

Uses for thermal output lp-HP STEAMhot water, LP stream

heat,hotwater,LP-HP steam

heat,hotwater,LP-HP steam

hotwater,LP-HP steam

Powere Density (kW/m^2) >100 35-50 0.036-0.05 0.015-0.036 0.0025-.0040

Nox(ldMMBtu)(not includ SCR)GAS.1-.2

0.013 rich burn 3-way cat. 0.17 lean burn 0.036-.0.05 0.015-0.036 0.0025-.0040

  Wood 0.2-.5  Coal 0.3-1.2

lb/MWh (not including SCR) GAS0.4-0.80.06 rich burn 3 way cat. 0.8 lean burn

0.17-0.25

0.08-0.02 0.011-0.016

  Wood0.9-1.4  Coal 1.2-5.0

Combined Heat and Power (CHP) TechnologyEduardo 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 Generation EFFp=Power Output/Energy inputElectricity Purchased From Central Stations Via Transmission Grid

Overall Efficiency of Separate Heat and EFFshp=(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 Power Total CHP System Efficiency EFFferc=(P+Q/2)/FSum of the net power and net useful thermal ouptu divided by the total

 fuel (F) consumed

FERFC Efficiency Standard EFFferc= (p+Q/2)/FDeveloped For the Public Utilitis Regulatory Act of 1978, the FERC methodologyattempts to recognize the quality of electrical outputrelative 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 fuelConsumption excludes the portion offuel udes for producing useful heat output. Fuel used to produce useful heat is calculated assuming typicalboiler efficiency, usually 80 percent

Percent Fuel Savings S=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 systemQ=Net useful Thermal Energy from CHP systemF=-Total fuel input to CHPEFFp=Efficiency of displaced electric generationEFFq= Efficieny of displaced thermal generation

Tempetute Classification   Waste Heat Source     Characteristics    Commercial waste Heat to Power Technologiea

High (>1200) Furnaces high quality heat Waste heat boilers and Steam Turbinessteel elcetric arc High heat transfer

steel heatinghigh power geration efficiencies

basic oxygen chemical and mechanical contaminants

aluminum reverberatorycopper reverberatorynickel refiningcopper refiningglass meltingiron cupolascoke ovensFume inceneratorsHydrogen Plants

Medium(500-1200) Prime mover exhaust streams Medium Power Generation EfficiencesWaste heat boilers and steam turbines(>500f)

gas turbine Chemical And Mechanical Contaminants Organic Rankine cycle (<800F) Reciprocating engine Kalina Cyle(<1000F)Heat-Treating furnacesovensDryingBakingCuringCement Kilns

Low(<500) Boilers Energy contained in numerous small 

Organc Rankin cycle (>300F Gaseous streams, >175F liquid streams)

Ethylene Furnaces sources Kalina Cycle(>200F)Steam condensate Recovery of combustion streams limited cooling water  due to acid concentration if tempeture 

furnace doorsreduced below 250F

annealing furnaces  Low power generation efficienciesair compressorsic enginerefrigeration condensorslow tempeture ovenshot 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.