Energieffektive og miljøvenlige afkøling ved hjælp af magnetiske køling. Nini Pryds

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1 Energieffektive og miljøvenlige afkøling ved hjælp af magnetiske køling Nini Pryds

2 Energy efficient and environmentally friendly cooling using magnetic refrigeration Partnership between: Duration: 4 years Ending date: Funding: 13.9 Mkr (programkomite for bæredygtig energi og miljø ) + 7Mkr (intern) 5 Ph.D. students 3 Postdocs Challenges Demonstrate cost-effective systems at commercially relevant temperature spans with high efficiency and environmentally friendly materials

3 Who is doing what? Risø-DTU Sintex Danfoss DTU Project Management Steering Committee Project manager Nini Pryds Technicians: Jørgen Geyti Finn Saxild Pernile Nielsn Materials development Luise Theil Kuhn/ Mohan (sep.) Modelling and simulations Nini Pryds Prototype development Christian Bahl WPL1.1 WPL1.2 WPL2.1 WPL2.2 WPL3.1 WPL3.2 WPL3.3 WPL3.4 Ph.D. Inge Ph.D. Britt Ph.D. Kaspar Ph.D. Rasmus Christian Ph.D. Jesper kurt Postdoc??

4 1. Ph.d. : Advanced magnetic materials 2. Ph.d. : Synthesize new magnetic ceramic materials 3. Ph.d. : Numerical modelling of the magnetic regenerator 4. Ph.d.: Modeling of permanent magnet and development 5. Postdoc : Design and dimensioning of a prototype system 6. Ph.d. : Magnetic regenerator design 7. Postdoc : Design and computer simulation of the magnetic refrigerator system 8. Postdoc : Magnetic refrigerator construction

5 What is the magnetocaloric effect? Discovered by Emil Warburg (1881) as the heating of Fe upon magnetization and the cooling of the same upon demagnetization (temperature change was a few mk!!!). Ann. Phys. (Leipzig) 13, 141 (1881)

6 The principle of the magnetocaloric effect = T 0 N N S ST T = T 0 +DT N S T = T 0 H S = S M + S L + S E S = S M + S L + S E T S = S M + S L + S E T "What is entropy, really?"

7 Low temperature Magnetic refrigeration Pioneered by Debye and Giauque in 1926/1927 Nobel Prize 1949 One-shot process - need for a cyclic process Giauque, Nobel lecture 1949

8 Advantages and Challenges Advantages Environmentally friendly Non-volatile, non-toxic refrigerants. Compact refrigerant is a solid Low frequency low noise. Very effective 60% of the Carnot limit has been demonstrated. Application areas Air conditioning units. Transport sector refrigerated containers. Home appliances. Challenges High magnetic fields are hard to produce. Cost of magnetocaloric materials and magnets.

9 T ( C) DS M (Jkg -1 K -1 ) La 0.67 Ca 0.33-x Sr x MnO 3 Gd 6 cm 2.1 cm 0 The four Ms of Magnetic refrigeration Magnet Materials T (K) Developments of new magnetocaloric materials Numerical model of the an AMR Modelling of permanent magnet Design of a prototype magnetic refrigeration machine Machine Model

10 Brit Hansen, Ph.d. Inge Biering, Ph.d. Pernile Nielsen, Laborant Luise Kuhn, Senior Scientist Mohan Menon, Senior Scientist

11 Ceramic materials Tuneable transition temperature Corrosion resistant Easy to handle May be shaped by a large variety of standard (and cheap) ceramic forming processes Extensive competences in the department La 3+, Sr 2+, Ca 2+ Mn 3+, Mn 4+ c b O 2- a

12 Differential Scanning Calorimeter Measures heat capacity of materials in a magnetic field Magnetic field : 0 T 1.8 T One run takes ~2 hours La 0.67 Ca 0.33 MnO 3 Stinus Jeppesen

13 Specific magnetization (Am 2 kg -1 ) Materials research La 0.67 Ca 0.33-x Sr x MnO 3 T ( C) Increased Sr content x = 0 0 H = 1.2 T x = DS M (Jkg -1 K -1 ) Gd Temperature (K) T (K)

14 Tape casting La 0,67 Ca 0,26 Sr 0,07 Mn 1,05 O 3 Plates have been prepared Density : 5.9 g/cm 3 Curie Temperature : 18 C Thickness : ~ 0.3 mm Functional grading Inge Biering

15 Materials with graded magnetocaloric effect COLD HEX HOT HEX T MCE x Low T c High T c Tapecasting of graded LSCM plates

16 The magnetocaloric effect is small Gadolinium is considered a benchmark material for room-temperature MR but still has a low ΔT ad!

17 Kaspar Nielsen, Ph.d. Rasmus Bjørk, Ph.d. Christian Bahl, Postdoc Jesper Hattel, Prof. DTU Anders Smith, Special consulant Brian Elmegaar, Lektor DTU Nini Pryds, Senior Scientis

18 Modelling of permanent magnet Permanent magnet arrays For reciprocating or rotating systems Optimization Close interaction with Sintex (Danish supplier of permanent magnets) Homogenous field of 1.1 T in the whole cavity. Experiment Simulation Rasmus Bjørk Anders Nordentoft

19 Permanent magnet Designed by Risø-DTU made by Sintex A/S

20 Modelling a refrigeration machine

21 Jesper Buch, Ph.d. Kurt Engelbert, Postdoc. Christian Bahl, Postdoc Jørgen Gyti, Technician Anders Smith, Special consulant Brian Elmegaar, Lektor DTU Nini Pryds, Senior Scientis

22 Device design and construction Lab device for easy and quick test Exploration of the extensive parameter space Close interaction with materials and modelling efforts Aim for prototype device at the end of plates of gadolinium 90 g total.

23 Movie!

24 Magnetic field dependence 0.3 T 0.6 T 0.9 T 1.2 T 1.3 T 7.7 C!!!

25 15 people working on MagCool Three-way approach Materials Modelling Design & construction Building on proven competences in ceramics and solid state chemistry Interplay between fundamental understanding and technological requirements Prototype device in 2010