December 13, 2012 Energy Efficient Cooling Information Service Webinar Series Christine Brinker and Gearoid Foley CHP with Absorption Chilling

Transcription

1 December 13, 2012 Energy Efficient Cooling Information Service Webinar Series Christine Brinker and Gearoid Foley CHP with Absorption Chilling

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3 Technical Assistance

4 Education and Outreach

5 Executive Order Calls for 40 GW new CHP by utedenergy/pdfs/chp_clean_energy_solution.pdf

6 Efficient Cooling Absorption Chilling Combined Heat and Power

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8 Webinar Purpose Technology overview & insights Energy impact Challenges Opportunities

9 CHP Prime Movers Combustion Turbines MW Microturbines kw IC Engines 30 kw 3 MW Fuel Cells 200 kw 1 MW 75% - 60% HEAT 25% - 40% Electricity

10 Thermally Activated Technologies Hot Water HEX Boilers/Steam Generators Absorbers Technologies: Steam Turbines Desiccants Adsorbers Cooling Applications: Cooling Freezing Dehumidification

11 Thermally-Activated HVAC Technologies are Key to Improving Overall Efficiency of DG Distributed Generation Technologies Thermally-Activated Cooling Technologies 800ºF Gas-turbine I.C. Engine Exhaust 600ºF Exhaust Fired Absorber Micro-turbine Fuel Cell 360ºF Double-Effect Absorption Chiller Steam Turbine Centrifugal Chiller 180ºF I.C. Engine Coolant Single-Effect Absorption Chiller Desiccant Technology Adsorber

12 Absorption Flow Cycle Return water from the building boils the refrigerant inside the evaporator and changes its form to vapor. Evaporator 44 0 F 0.1 psia 42 0 F The latent energy used is drawn from the building water system sensible energy thus cooling it F Chilled Water Return Water Refrigerant Refrigerant Vapor

13 Absorption Flow Cycle The refrigerant vapor must be removed to maintain the vacuum so a LiBr solution is sprayed into the absorber. Evaporator 44 0 F 0.1 psia 42 0 F The LiBr bonds with the vapor in the absorption process and forms a dilute LiBr solution F Absorber Chilled Water Return Water Refrigerant Refrigerant Vapor Concentrated LiBr Dilute LiBr

14 Absorption Flow Cycle The dilute LiBr solution is directed to the generator where heat is applied to drive off the refrigerant vapor. The concentrated or re-generated LiBr solution is returned to the absorber to collect more refrigerant vapor. Evaporator 54 0 F 44 0 F Absorber 0.1 psia 42 0 F 14.0 psia F Heat Input Generator Chilled Water Return Water Refrigerant Refrigerant Vapor Concentrated LiBr Dilute LiBr

15 Absorption Flow Cycle A condenser is added to return the refrigerant vapor to its original liquid form before entering the evaporator to begin the cycle again. Condenser Evaporator 54 0 F 44 0 F Absorber 0.1 psia 42 0 F 14.0 psia F Heat Input Generator Chilled Water Return Water Refrigerant Refrigerant Vapor Concentrated LiBr Dilute LiBr

16 Absorption Flow Cycle Condenser water flows through the system to remove heat energy from the chiller and is sent to a cooling tower where the heat is released to the atmosphere F Condenser 44 0 F Generator Evaporator 0.1 psia 42 0 F 14.0 psia 54 0 F F Chilled Water Return Water Refrigerant 85 0 F Absorber Heat Input Refrigerant Vapor Concentrated LiBr Dilute LiBr Condenser Water

17 Absorption Chillers Hybrid HW & Exhaust Fired Absorber Single Effect: Low Temp Activation, 200 F Cost Effective Simple Good Efficiency 0.7 COP Double Effect: High Temp Activation, 350 F Expensive Complex High Efficiency 1.2 COP Wide range of models from <100 tons to >1,000 tons Activated by Steam (15 psi psi), Hot Water or Exhaust 4 to 5 GPM Condenser Water, Large & Heavy, Slower Response

18 Absorber Heat Exchangers Cooling Tower System Controls Cd Pump & By-Pass Heat Load Control Sensors, PV&F 3-Way Valves Components

19 Energy Impact Cooling output maximum during peak demand on utility Adds from 20% to 30% effective CHP power output when offsetting electric cooling Provides inlet air cooling to maintain generator at design capacity during peak demand Offsets highest electric rates for host site Reduces summer peak energy use Higher energy related emissions reductions as chiller offsets peaker plants

20 Simple Cycle Combustion Turbine CHP High temperature/high volume Flue Gas Heat Recovery Steam Generators High Pressure Steam Co-Firing Steam Turbine Chillers Steam Fired Absorbers Exhaust Fired Absorbers Heating & Cooling

21 CT CHP System HRSG provides high pressure steam to chillers or heating distribution system. Duct firing or co-firing increases thermal capacity and CHP efficiency. HRSG with Duct Burner provides variable thermal output. Additional cost for additional thermal capacity is minimal. Heat Recovery Steam Generator (HRSG) Gas Turbine: KW Gross 59 F Inlet Air, 500 Ft Ele, 60% RH: Total Auxiliary Power Consumption incl Compressor: Net Turbine Power Production: HRSG: Process Steam Pressure: Process Steam Temperature: Steam Contributed by Gas Turbine: Steam Contributed by Ductburners: Deaerator Steam Consumption: Boiler Steam Flow: Steam Flow to Process: Chillers: Steam Flow to Chiller System: Tons of Refrigeration 1.2 COP: Cycle Performance (lower heating value basis): Net Turbine Heat Rate: Gross Plant Heat Rate: Average Cycle Efficiency: 5,203 KW 64 KW 5,139 KW psig 366 F 29,367 lb/hr 36,379 lb/hr 4,551 lb/hr 65,747 lb/hr 61,196 lb/hr 61,196 lb/hr 6,120 Tons 11,670 BTU/KW 3,970 BTU/KW 86.0 %

22 CT CHP System Typical Application: 1.25 M sq ft Commercial Complex Electric based Design -Electric Demand w/ Electric Chillers = 6.2 MW -Electric Chiller Load = 25% / MW / 2,583 Tons -Net Demand w/o Electric Chiller = 5.25 MW CHP Design Smaller Generator Smaller Electrical Infrastructure Higher Efficiency = Lower Fossil Fuel Use Displace Boilers = Lower Emissions -CT Generator Electric Output = 5.25 MW -Steam Driven Chiller Output = 2,803 Tons -Total Effective Output = 6.2 MW

23 UMD CHP System Microturbine/Absorber/Desiccant Natural Gas MICROTURBINE 100 kw (340,000*) Exhaust 500 F 40 kw (140,000*) Exhaust 225 F DESICCANT SYSTEM 3000 CFM of Dry Air 262 kw (895,000*) * Btu/hr ABSORPTION CHILLER 70 kw (20 tons) Chilled Water Air to Zone 1 67 kw Electric Power HHV Efficiency: 25% generator only 64% with chiller 79% with desiccant

24 Comparative Effects Thermal Technologies Only 25% 25% Electric Demand Reduction & Improved IAQ

25 Challenges Absorbers are heavier and more expensive than electric chillers Absorbers have higher parasitics particularly condenser water flow Absorbers can require more TLC than electric chillers somewhat mitigated with single stage simplicity Some unique design requirements including CW temp control and flow variability High pressure steam may require licensed operators Lack of acceptance and engineering knowledge

26 Hot Water Fired Single Stage Absorbers Temperature of the coolant leaving the exhaust HEX as well as the jacket return requirement have a major impact on chiller system design. Capacity 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Single Stage Absorber Performance Capacity COP COP Lower temperatures reduce chiller capacity and COP. Absorber HW Inlet Temperature

27 Exhaust Fired Absorber Capacity and Efficiency vary directly with Waste Heat Temperature Control of hot exhaust gas at low pressure expensive and critical Co-firing mixes exhaust with gas to supplement unlimited tonnage Heating can be provided as well as cooling Capacity 100% Single Stage Waste Heat Fired COP.7 70% 500 F 600F 700 F.6

28 Opportunities Wide range of absorption choices to match facility needs Absorption required for high annual utilization of CHP thermal output in space conditioning applications Many Commercial and Intuitional facilities can benefit from CHP with absorption chilling Office Buildings, Retail, Malls, High Rise Residential Hotels, Schools, Colleges, Hospitals Process loads such as Data Centers ideally suited to CHP with absorption. Each kw used by a server requires a kw of cooling and CHP with absorption provides approx. 1 kw of cooling per kw of power

29 CHP Choices & Cooling T/E Ratio Generator Range Cooling TAT Av. Ton/kW Gas Turbine 1 > 3 MW 2E Absorber Exhaust Fired Microturbine < 1 MW 1E Absorber Exhaust Fired IC Engine.1 to 3 MW 1E Absorber Hybrid Abs Fuel Cell >.25 MW 1E Absorber Note 1: Double T/E Ratio with Duct Firing

30 System Optimization Electric refrigeration chiller cost can be reduced and its efficiency doubled by using a heat recovery absorber. Existing Chillers Performance CHP System Existing Refrigeration Chillers Power Generator Chiller Output Tons 500 Electric Output kw 2,388 Chiller Efficiency kw/tr 2 LHV Elec Efficiency % 39.1% Chiller Input kw 1,000 Fuel In MBH 22,936 CT Fan Input kw Air Cooled Total HR 3 MBH 8,500 Total Parasitics 1 kw 0 1E Absorber Output Tons 496 Abs/Cond Heat Rejection MBH 14,450 Replacement Chillers CHP Refrigeration Chiller Elec Centri Chiller Output Tons 500 Elec Chiller Efficiency kw/tr New Refrigeration Chillers Elec Chiller Input kw 347 Chiller Screw Output Tons 500 YK Cd Output MBH 7,185 Chiller Efficiency kw/tr Chiller Input kw CHP System Parasitics CT Fan 2 HP 30 Electric Chiller CT Fan 2,4 HP - Total Parasitics 1 kw 56 Absorber CT Fan 2 HP 50 Total Parasitics 1 kw 101 Notes: 1 Parasitics include cooling tower, condenser pump and absorber 2 Design wet bulb temperature = 73 F 3 Includes Jacket + Exhaust, excludes 2nd Stage Intercooler 4 CT not required when Abs operating or use Abs CT

31 Utility Advantage CHP with absorption provides highest impact on load reduction during peak demand on grid Levelizes both electric utility and gas utility demand profiles through 12 months Absorption cooling offsets last call peaker plants reduced energy cost and highest emissions reductions Offsets low load factor T&D and high temp line losses Dispatchable and does not interfere with base load Keep customer energy costs low and keep customer

32 Utility Assistance Programs Grant Program Bonus for adding Cooling to CHP NJ grant program has a 30% cap for CHP without Cooling and increases the cap to 40% for CHP with cooling Demand Reduction counts added effective kw reduction due to cooling component of CHP Need to calculate offset based on electric chilling efficiency Energy Reduction counts added effective kwh reduction due to cooling component of CHP Need to calculate offset based on electric chilling efficiency

33 Q & A No matter which basis is used to choose the prime mover, the degree of use of the available heat determines the overall system efficiency; this is the critical factor in economic feasibility. Therefore, the thermal/electric ratio of the prime mover and load must be analyzed as a first step towards making the best choice. Maximizing efficiency is generally not as important as thermal and electric utilization.. ASHRAE Design Guide, Chapter 7 CHP Systems

34 Stats In the U.S., at least 335 CHP systems comprising 3,846 megawatts of electrical generation currently use the waste heat to run absorption chillers.

35 Snowbird Ski Resort

36 Example Incentives Arizona $ /kW (Southwestern Public Service) New Mexico Custom measure Up to $400/kW

37 Next Steps Utilities Policymakers End Users

38 For More Info Christine Brinker Exec Director U.S. DOE Intermountain CEAC Gearoid Foley Senior Technical Advisor U.S. DOE Mid-Atlantic CEAC