DISCONTINUOUS THERMO-CHEMICAL MAGNESIUM HYDRIDE-ALANAT-HEAT PUMP

Transcription

1 DISCONTINUOUS THERMO-CHEMICAL MAGNESIUM HYDRIDE-ALANAT-HEAT PUMP COMPACT STORAGE AND HEAT TRANSFORMATOR Jürgen Kleinwächter, Sunvention GmbH Michael Felderhoff, Max-Planck Institute of Coal Research

2 The Age of Fossile Energy The Solar Age Sun Sun Power Station Consumer Power Station Storage of Solar Heat Consumer Oil, Coal Storage (fossile) Earth

3 System 1 Elektrolyse H 2 O 2 Brennstoffzelle η total = 0,049 η 1 = 0,1 η 2 = 0,7 η 2 = 0,7 η 1 = 0,3 System 2 η 3 = 0,4 η 2 = 0,7 Elektrolyse H 2 HO 2 2 Brennstoffzelle η 2 = 0,7 η atotal = 0,147 η btotal = 0,084 = Verstromung bei Ferntransport H 2 / O 2 = Wiederverstromung im internen Kreislauf mit Stirlingmaschine System 3 η 1 = 0,8 Mg H 2 Mg + H 2 = Mg H 2 + E E = 1 kwh/kg Mg + 70 g H 2 Mg H 2 + E = Mg + H 2 H 2 η 2 = 0,2 η total = 0,16

4 Dissociation pressure of magnesium hydride in function of the temperature

5 Thermo chemical heat pump process Inp Metall B Metall A Qzu H 2 Qab Qab H 2 Qzu T h T mb T ma T u T L T

6 Vapour Pressure Curves of MgH 2 and NaAlH 4 60 Dr uc k [b ar] Pressure [bar] Na 3 AlH Al+H 2 NaAlH 4 MgH 2 Mg + H 2-37 kj/mol H kj/mol H2-75 kj/mol H kj/mol H Temperatur [ C] Temperature [ C] Kat. NaAlH4 ΔH = 55 kj/mol Energy density = ca kj/kg

7 MgH 2 Reactor Fix-Focus Prototype

8 Pilot installation of the solar storage plant 1: Fix Focus concentrator 2 : Receiver 3: Storage cylinder 4: Connection motor-storage 5: Stirling working cylinder 6: Stirling flywheel 7: Air pressure vessels 8: Generator 9: Insulated alanat vessel 10: Hydrogen measurement and control devices 11: Control of Fix-Focus-mirror 12: Vacuum connection of insulation 13: MgH 2 cartridge 14: Stirling heater head

9 The Mid Temperature Stirling Engine Third World Stirling Engine P Nom = 1,5kW el for heater head temperatures between 100 and 400 C with η max = 18% bmu18.org :37 30 Druck Motordruck [bar] Windkesseldruck [bar] Hu braum [L] Druck [bar] ,0 0,5 1,0 1,5 2,0 2,5 3,0 3,5 4,0 4,5 5,0 Hubraum [L]

10 Stirling gearbox with discontinuous displacer movement for high efficiency at low temperatures differences

11 Alanat Batteries Measurement and test stand for studying of the coupling of Alanat and MgH 2 Sectional view of the vacuum isolated storage cylinder with receiver for molten salt as heat transfer medium Demonstration and test plant for studying the heat transfer between MgH 2 -cartridge and molten salt Solar test stand

12 Component size Energy data Input of solar energy Aperture area 2,4 m 2 with P solar direct =800 W/m 2 η mirror *η receiver = 0,81 1,55 kw th daily 8h. heat input at 400 C 12.3 kwh th MgH 2 17 kg 8,8 kwh Alanat 30 kg 8,8 kwh th heat at 400 C in MgH 2 Sensible heat capacity About 50 kg Salt, 110 kg Steel at 50 K 1,9 kwh th Stirling Engine 1,5 kw Nom El η Motor = 18 % nearly isotherm at 400 C Heat needed = 8,3 kw th About 2 h work 3 kwh Electricity Dimensioning of the pilot plant (optimized actual conditions) Component size Energy data Input of solar energy Aperture area 15 m 2 with P solar direct = 800 W/m 2 η mirror *η receiver = 0,81 12,15 kw th daily 8h. heat input at 400 C 77 kwh th MgH 2 92 kg 48 kwh Alanat Sensible heat capacity Powerfluid engine 160 kg About 30 kg Salt, 100 kg Steel average η Motor = 33 % isotherm at 400 C 48 kwh th heat in MgH 2 at 50 K 1,13kWh th Heat needed = 3 kw th In 24h work 24 kwh el are produced Dimensioning of a 24h solar storage plant (nominal conditions)

13 Results T[ C] a b c T[ C] d e Motor Engine anon 10 min. isotherm! f g 350 H 2 Valve Ventil opens öffnet MgH Alanat H 2 Valve Ventil opens öffnet Alanat MgH 2 12:00 14:00 15:30 17:00 time Zeit 22:00 22:15 22:30 22:45 time Zeit

14 The Powerfluid Technology cooler heater 1 3 motor-2 pump motor-1 G 2 4 counterflow heat exchanger P cold 2 3 hot T T max 3 4 0,9 efficiency 0,8 0,7 0,6 0,5 0, kw e Carnot limit 100 MW e kw e > 500 MW e 4 3 > 100 MW e V 1-2 = isothermal compression 2-3 = 1-2 isobaric = isotherme expansion Kompression 3-4 = 2-3 isothermal = isobare Expansion expansion 3-4 = isotherme Expansion 4-1 = isobaric contraction 4-1 = isobare Kontraktion 1 S 0,3 0,2 0,1 1 kw e 10 kw e 2 1 > 100 MW e 1) steam Rankine cycle 2) open Brayton cycle without heat recuperation temperature [ C] 3) close Brayton cycle with intake-exhaust pressure ratio of 4 and heat recuperation 4) steam Rankine combined with open Brayton topping cycle 5) high-temperature Stirling engines

15 Fix-Focus mirror Production of a point focus with a linear lens

16 Fresnel mirror, schematic representation Concentration factor, logarithmic representation

17 Mass production (Powerfluid engine) Day-time operation 24hr operation No heat-storage Thermo-chemical heat-storage 1 kwe 3 kwe 1 kwe 3/7.2 kwe Manufacturing and investment cost ( ) o Fix-focus concentrator o receiver/heat-storage system o Thermodynamic converter (a) Total Overhead, distribution, profit margin (%) 35% 35% 35% 35% Investment cost before installation Installation cost (10% of investment cost) Investment cost Manufacturing cost per kw e ( /kw e ) Investment cost per kw e ( /kw e ) Cost per kwh e Investment cost ( ) Yearly electrical output (kwh e ) (1) Annual amortization and financing cost ( ) (2) Yearly maintenance cost ( ) (3) Cost per kwh e (cents) 14,2 8,2 17,4 13,5 (1) Direct normal solar irradiation (kwh/sqm and year) (2) Depreciation (yrs) 20 (a) Cost assumed ( /kwe 750 for 3 kwe engine (2) Financing cost (%) 8,00% for 1 kwe engine (2) Amortization factor (interest rate of 8%, 20 years) 0,0943 (3) Maintenance cost as % if investment cost (%) 2,50%

18 Thanks for your attention Sky over Plataforma Solar, Andalusia, Spain, observed 17. November 05 by Jürgen Kleinwächter and Don Watson.