Chemical heat storage using Na-leach

Transkript

1 Hilfe2 Materials Science & Technology Chemical heat storage using Na-leach Robert Weber Empa, Material Science and Technology Building Technologies Laboratory CH 8600 Dübendorf

2 Folie 1 Hilfe2 Diese Folie enthält zwei Mastergruppen (Master und Titelmaster), welche den Corporate-Design-konformen Auftritt definieren. Der jetzt zugewiesene Empa-Master 1 sieht für die Titelfolie das Empa-Logo vor. Den weiteren Folien ist kein Logo zugewiesen. Für längere Vorträge mit Zwischentiteln empfehlen wir, den Folien mit Zwischentiteln den Empa-Master 2 (mit Logo unten rechts) zuzuweisen. Dazu öffnen Sie via Ansicht > Aufgabenbereich > Foliendesign-Entwurfsvorlage rechts die Masterauswahl. Nun markieren Sie im linken Ansichtsfenster die Folien, denen Empa-Master 2 zugewiesen werden soll (mindestens zwei, ansonsten für den ganzen Satz Empa-Master 1 verwendet wird). Weitere Hilfe erhalten Sie bei Monika Ernst, 4995 (Empa, Dübendorf) M. Ernst;

3 Content of the presentation Long term storage: State of the art Thermo chemical storage: principle Concept Design Status of work Future work Empa, RW 118,

4 Long term storages: State of the art Long term storages (sensible storages) cover typically 30% to 60% of the needed heating energy during winter time. Domestic hot water not always can t be produced directly. Advantages of water storages: Known technology No dangerous material Disadvantages of water storages: Permanent loss of heat Voluminous Empa, RW 118,

5 Goal: Solar covers 100% heating demand Precondition: Building in passive house or Minergie standard Central-European climate Technical requirements: 30 50m² solar collectors 20 40m³ water storage Empa, RW 118,

6 Storage Volume and Solar Fraction 100% 90% Annual Solar Fraction 80% 70% 60% 50% 40% 30% 20% 10% 0% Short Term Storage Passiv house with 4 Persons DHW = 50 liter / Person (50 C) Losses includet Storage Volume/Collector Area [l/m²] Long Term Storage Collector Area [m²/person] Empa, RW 118,

7 Conclusion long term storage: To cover the last 10% of heat energy, unproportionally high storage volume are needed Solar collector area needs to be large to cover the permanent losses New possible concept: chemical heat storage No losses during storage time High heat capacity Costs shall not be higher than with water storage Empa, RW 118,

8 Thermo Chemical Storage: Principle Charging solar collector H 2 O vapour (45 mbar) H 2 0 NaOH ground heat exchanger heat from collector (20 C) (150 C) waste heat Empa, RW 118,

9 Thermo Chemical Storage: Principle Discharging Empa, RW 118,

10 Potential of a NaOH Storage System Heat capacity for heating purposes: 6 time better than a water storage Heat capacity for DHW: 3 time better than a water storage Source: J. van Berkel Empa, RW 118,

11 Concept: Charging the storage Water ground heat exchanger Vapor conc. Soda lye diluted Soda lye Solar collector Empa, RW 118,

12 Concept: Discharging the storage Water ground heat exchanger Vapor Vapor conc. Soda lye diluted Soda lye Heating Double-stage Heat exchanger Single-stage Heat exchanger Domestic hot water Empa, RW 118,

13 Hydraulic scheme laboratory prototype: P4 P Wasser ~10 C Kühlnetz EMPA Wasser ~60 C - 95 C Boiler P2 P1 Widerstands -heizung Frischlauge Empa, RW 118,

14 Setup of the laboratory prototype Empa, RW 118,

15 Status of the work on the NaOH Storage The storage was built and filled with soda lye. Loading tests has been performed. During that test,higher concentration of NaOH reached than expected. The high concentration of NaOH lye led to adjustments: Silicone hoses, which has been corroded in the lye are replaced. The high viscosity of the concentrated lye needed a change in the design of the tubes and pumps. Simulations on the laboratory prototype show (with assumptions about losses): Calculated efficiency about 59% (heat out/heat in) Volume ratio (compared to water) 290% (only NaOH considered) Empa, RW 118,

16 Ongoing work: The simple simulation model will be upgraded and translated to Fortran (TRNSYS). TRNSYS simulations will be made to show the performance of the storage under real conditions. In the frame of the IEA Task 32 these results are compared with other storages. The laboratory prototype will be upgraded with doublestage heat exchangers. Further simulations are made to optimize System components (collector area, ground heat exchanger, cost of the system, etc.) Empa, RW 118,

17 Galerie Empa, RW 118,

18 Thank you for your attention! Empa, RW 118,