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Fuel Cell Systems for Buildings. US Energy Use and Emissions. Total Annual US Primary Energy Use 85.8 Quadrillion Btus. Total Annual US CO2 Emissions 1460 million metric tons. Combined Heat & Power (CHP) For Building Applications.
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US Energy Use and Emissions Total Annual US Primary Energy Use 85.8 Quadrillion Btus Total Annual US CO2 Emissions 1460 million metric tons
Combined Heat & Power (CHP)For Building Applications Simultaneous production of heat and power for useful purposes 0.67 0.33 1 Conventional Electric Power Generation 0.2 0.4 1 0.4 Combined Heat and Power
Fuel Cell Systems for CHP Applications in Buildings • Wide size range • Excellent full and part load performance • Minimal environmental impact • Simple maintenance • Site friendly
FC System Integration for Buildings Typical 200kWe/200kWt PAFC System Exhaust 18% Thermal Energy 40 – 80 C (100 – 175 F) 40% Heat Recovery 40% 42% 100% 85% Fuel Cell Stack Air & Thermal Management Fuel Processor Power Conditioning Fuel Power 2% Heat
Fuel Cell CHP System Economics • Cost of electricity ($/kWh) Maint 0.01-0.03 Net cost 0.05–0.17 Capital 0.01–0.08 = Fuel 0.06 + + HR Credit 0 – 0.03 - Basis: CC = $500 – $3000/kW r = 10% LF = 0.5 FC = $8/MCF E= 45% T= 40% A= 80%
FCCHP Economics: Commercial Bldgs Basis: LF = 0. 5 F1 = 0.3 r = 12% N = 20years E=0.4 T=0.4 A=0.8 MC = $0.01/kWh
Fuel Cell/Heat Pump/Thermal Storage CHP System Heat Loss, QL Heat Rejection, QREJ Residence Thermal Storage Tank Thermal Output Elect Water Htg, EDW Thm Water Htg, QDW Exhaust Gases QFC Thm Space Htg, QTSH Elect Space Htg, QESH Heat Pump Space Cooling, QAC Fuel Fuel Cell System FFC EESH EAC Supply Fan, EF Electric Output Lights and Appl, ELA EFC Electricity Thermal Energy
Typical House Characteristics • Floor space: 195 m2 (2100 ft2) on 1-floor • Inside temperature: 21°C(70°F) heating 24°C(75°F) cooling • Unconditioned crawl and attic spaces • 4 person family – 2 daytime occupants • Typical residential construction: • Roof (R-30); Walls (R-11); Floor (R-19) • Double glazed windows with interior blinds • Building infiltration: medium leakage (0.8 ACH)
1 4 3 2 Selected Locations for Analysis
Heat Pump Subsystem TS,i TFCC,e TTS Fuel Cell System Thermal Storage Tank TTS, mTS TFCC,i TFCC,x VSD TTSH,i TDW TCW THW Electric energy SupplementaryElectric Water Heater Thermal energy T Schematic of FC CHP System
Energy Use by Service Atlanta Syracuse
Comparison of Energy and Life Cycle Costs to Conventional Systems • All-electric conventional system components are • Electric heat pump • Electric domestic water tank • Electric and natural gas conventional system components are • Electric air conditioner • Natural gas furnace for space heating • Natural gas fired domestic water tank • FC CHP system components are • Fuel cell system • Thermal storage tank • Electric heat pump • Life cycle cost function is • Life of all energy systems is 20 years • Rate of return on capital, r, is 10 percent
Characteristics of Residential FC CHP • Residential FC CHP system characteristics: • Fuel cell size: 4-5 kWe capacity depending on climatic conditions • Heat pump performance: SEER of 10 • Thermal storage tank size: 300-liter • FC CHP efficiencies: • 73 percent in cold climates • 63 percent in warmer climates. • FC CHP reduces energy use • FC CHP reduces emissions • FC first cost must be reduced to $500/kWe to yield LCC comparable to conventional systems
General Prospects forBuilding Fuel Cells • Cost goals (~$500 - $1000/kW) are less stringent than for vehicles • Weight and volume criteria are less stringent that for vehicles • Suitable fuel (natural gas) is widely distributed • Thermal energy is useful (particularly in residential applications) • Some building applications already require back-up power source • No regulatory mandate (like zero emissions vehicle mandate in California) • Technological change in building industry is driven by widely dispersed stakeholders
Integration of Vehicle and Building Systems Hydrogen Storage and Dispensing Hydrogen Vehicle Electricity Heat Natural Gas Hydrogen Fuel processor Electrolyzer