GAS-SOLID REACTIONS FOR HEAT APPLICATIONS

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1 GAS-SOLID REACTIONS FOR HEAT APPLICATIONS Marc Linder, Inga Utz, Franziska Schaube, Margarethe Molenda, Antje Wörner Institute of Technical Thermodynamics, German Aerospace Center DLR e.v. Slide 1,

2 Outline Underlying principles of gas-solid reactions for heat application Advantages Challenges Current activities at the DLR Direct heat transfer concept based on CaO/Ca(OH) 2 Process integration: Sorption system based on metal hydrides Summary Slide 2

3 Reversible Gas-Solid Reactions Solid Reactant A + Gas Solid Reactant B + ΔH Research Group Thermal Energy Storage at DLR Solid state hydrogen storage Reactor development and modelling Coupling to fuel cell Themo-chemical heat storage High storage density Adaptability to different temperature ranges Constant operation temperature Long-term storage possible without losses => separation of reactants Slide 3

4 Thermo-Chemical energy storage - system Complex system Storage of gaseous reactant necessary Additional energy required (for compression) Slide 4

5 Thermo-Chemical energy storage - material Low thermal conductivity of powder bed Thermal power? Reactor design Material costs Amount of useful cycles determines the amortization periode Seasonal storage Day / Night storage Continuous operation (sorption system) Thermal Conductivity in W/mK Temperature in C F. Schaube et al., High Temperature TC Heat Storage for CSP using Gas-Solid Reactions, Proceedings of SolarPaces 2010, Perpignan, France (2010) Slide 5

6 Key factors: Development of reactor systems Process integration Current activites on Gas-Solid Reactions for heat applications at DLR: Development of reactor systems: Concept of direct heat transfer CaO/Ca(OH) 2 Integration into an existing process: Hydrogen driven cars with compressed hydrogen tank and FC Sorption system based on metal hydrides Slide 6

7 CaO/Ca(OH) 2 system Temperatur range: C CSP plants Bed with low thermal conductivity F. Schaube et al., High Temperature TC Heat Storage for CSP using Gas-Solid Reactions, Proceedings of SolarPaces 2010, Perpignan, France (2010) Slide 7

CaO/Ca(OH) 2 system Direct heat transfer concept Heat transfer

Evaporator + Superheater Operation with N 2 /H 2 O mixture

8 CaO/Ca(OH) 2 system Direct heat transfer concept Heat transfer not limiting Dew Point Hygrometer Reactor with Isolation Evaporator + Superheater Operation with N 2 /H 2 O mixture (sensitivity of current powder) Water Treatment F. Schaube et al., High Temperature TC Heat Storage for CSP using Gas-Solid Reactions, Proceedings of SolarPaces 2010, Perpignan, France (2010) Slide 8

9 Process integration: Sorption system for Hydrogen driven cars Manufacturer Type of Car H 2 -Storage Daimler B-Klasse F-CELL 700 bar Ford Ford Focus FC 350 bar GM/Opel Hydrogen bar Honda FCX Clarity 350 bar Hyundai/Kia Borrego 700 bar HyTruck Fuel cell truck 350 bar Toyota FCHV adv 700 bar Volkswagen HyMotion 350 bar Daimler Citaro FC-Hybrid Bus 350 bar Available pressure difference is so far not used Cars at the Ride & Drive Event of the WHEC 2010 Stored potential energy is wasted Compressed H 2 tank contains chemical and potential energy Potential energy is dissipated Fuel cell/engine consumes only chemical energy Slide 9

10 Sorption system - generation of cold ln p p R Q Amb H 2 (CH 2 ) p C Q C H 2 (FC) T Amb T C 1/T Regeneration at ambient temperature Generation of cold by means of desorption Continuous operation possible with constant hydrogen current (two alternating reactions) Potential energy is used to generate cold, e.g. for air-conditioning Slide 10

11 Sorption system test bench Hydrogen inlet Max. 55 bar Sorption system Hydrogen outlet Min. 6 bar Slide 11

Sorption system - reaction beds Fast reaction

, Experimental analysis of fast metal hydride

12 Sorption system - reaction beds Fast reaction kinetics are necessary (high thermal power) Sufficient heat management Hydrogen distribution Linder et al., Experimental analysis of fast metal hydride reaction bed dynamics, Int. J. Hydrogen Energy 35, , 2010 Slide 12

13 Sorption system metal hydride Low temperature metal hydride with a high equilibrium pressure (around 10 5 C, desorption) Adaptation to fuel cell requirements Fast reaction kinetics 80 % H 2 desorbed within 60 5 C Slide 13

14 Sorption system measurement results Two alternating reactions (regeneration and cooling effect) Regeneration at bar Cooling at 6 10 bar Ambient temp.: > 30 C Cooling temp.: < 12 C Cooling power: ~ 900 W Linder et al., An energy-efficient air-conditioning system for hydrogen driven cars, Int. J. Hydrogen Energy, Article in Press Slide 14

15 Sorption system general comments Main idea: No additional fuel consumption => partial re-use of compression work No additional refrigerant necessary System weight and volume (MeH part, extrapolated to 2 kw system) Weight: ~ 12.5 kg Volume: ~ 3 l Operation principles => Dependency on hydrogen consumption P Cool ~ 0.2 * P el, FC Bypass for higher flow rates Slide 15

16 Summary Thermo-Chemical Energy storage offers several advantages like potential high storage density, lossless long-term storage but the crucial points are adapted reactor systems and process integration Reactor development: CaO/Ca(OH)2 with direct heat transfer Integration into an existing process: Sorption system for onboard cold generation Slide 16

17 Thank you for your attention! Marc Linder DLR German Aerospace Center Slide 17

Answer: Volume of water heated = 3.0 litre per minute Mass of water heated, m = 3000 g per minute Increase in temperature,

Answer: Volume of water heated = 3.0 litre per minute Mass of water heated, m = 3000 g per minute Increase in temperature, Question A geyser heats water flowing at the rate of 3.0 litres per minute from 2 7 C to 77 C. If the geyser operates on a gas burner, what is the rate of consumption of the fuel if its heat of combustion