Thermal Energy Storage Jose Pereira da Cunha Materials Review T - PowerPoint PPT Presentation

Phase Change Materials for Thermal Energy Storage Jose Pereira da Cunha

Materials Review T melt Δ H fusion E density T melt Δ H fusion E density Organic Melts CAS Mass Inorganic Eutectics Ratio °C kJ/kg kWh/m 3 °C kJ/kg kWh/m 3 Oxalic acid dihydrate 6153-56-6 105 370 178 AlCl3-ZnCl2 48-52 114 607 395 Maleic acid 110-16-7 131 235 109 Adipic acid 124-04-9 152 220 101 AlCl3-NaCl 80-20 106 285 156 HDPE MI 12g/10min 130 255 67 AlCl3-LiCl 83-17 114 250 150 9002-88-4 HDPE MI 2g/10min 135 260 69 AlCl3-KCl 78-22 128 253 150 Phthalic anhydride 85-44-9 131 160 68 AlCl3-CaCl2 78-22 119 267 149 2-Chlorobenzoic acid 118-91-2 142 164 75 FeCl3-LiCl 57-43 150 353 257 d-Mannitol 69-65-8 165 300 140 AlCl3-KCl-LiCl 44-52-3 85 196 111 T melt Δ H fusion E density Inorganic Melts CAS AlCl3-KCl-NaCl 58-26-15 88 191 102 °C kJ/kg kWh/m 3 LiNO3-KNO3 33-67 133 160 99 Ba(OH) 2 -(H 2 O) 8 12230-71-6 78 270 164 Mg(NO 3 ) 2 -(H 2 O) 6 13446-18-9 90 150 72 +18% NaNO3 30-18-52 120 135 78 MgCl 2 -(H 2 O) 6 7791-18-6 117 120 68 KNO3-NaNO2 56-44 141 145 91 + 7% NaNO3 58-7-35 142 266 144 T melt Δ H fusion E density Mass Organic - Inorganic Eutectics Ratio KNO2-NaNO3 48-52 149 153 94 °C kJ/kg kWh/m 3 K2CO3-Urea 15-85 102 225 100 LiNO3-KCl 44-56 160 272 174 NaCl-Urea 20-80 103 254 108 +5% NaNO3 53-5-42 160 266 173 KCl-Urea 18-82 115 243 105 LiNO3-NaNO3 48-52 190 280 175 T melt Δ H fusion E density Mass +1% LiCl 48-1-51 180 267 169 Ratio °C kJ/kg kWh/m 3 KNO3-Mg(NO3)2 46-54 178 128 83 Salicylic acid - Malonic acid 57-43 87 217 98 Salicylic acid - Benzoic acid 33-67 107 164 66 NaOH-KOH 37-63 170 207 127 Malonic acid - Benzoic acid 36-64 107 183 77 LiOH-LiNO3 19-81 183 776 484 Benzoic acid - Oxalic acid 67-33 114 312 135 Succinic acid- Benzoic Acid 29-71 116 189 77 Malonic acid - Succinic acid 47-53 119 268 126

Organic TGA Analysis • Organics sublime around their melting point; • Adipic Acid seemed suitable, but thermal stage • Oxalic Acid dihydrate has a initial dehydration stage; indicated also sublimation in its melting point;

Inorganic TGA Analysis • Salt Hydrates dehydrate in their melting point:  Barium Hydroxide lost 1 water molecule;  Magnesium Nitrate lost 4 water molecules;  Magnesium Chloride lost 5 water molecules;

Organic DSC Analysis • Mannitol and HDPE are the most suitable for • Adipic Acid proved thermal stability in thermal storage; closed container; • Normal lid tests showed good cycling properties; Normal lid Hermetic lid

Organic DSC Analysis • • 2-Chlorobenzoic acid and Phthalic Anhydride were Oxalic acid dihydrate showed poor thermal cycling even in thermally stable only in hermetic container; closed lid; • Maleic Acid was inconclusive (large sub cooling didn’t allow full crystallization);

Inorganic DSC Analysis • Salt Hydrates • Dehydration leads to evolution of melting point; • In closed container, only Barium Hydroxide proved not suitable for thermal storage;

Inorganic DSC Analysis LiNO3 – KNO3 LiNO3 - KCl • Eutectic Mixtures • Excellent Thermal Properties; • Very hygroscopic;

Inorganic DSC Analysis LiNO3 – NaNO3 NaNO2 – KNO3 • Eutectic Mixtures • Only Nitrite mixtures were non hygroscopic;

Conclusions • Organics tested need to be enclosed for T melt Δ H fusion Cp s Cp l E density Δ T Water Organic Melts CAS Lid °C kJ/kg J/kg.K kWh/m 3 for 1m 3 thermal storage; Oxalic acid dihydrate 6153-56-6 Hermetic 105 269 2108 2890 135 116 Maleic acid 110-16-7 Hermetic 138 305 1662 2335 144 124 Normal 153 96 810 1330 40 35 Adipic acid 124-04-9 • Only Mannitol and HDPE are stable at their Hermetic 155 219 1750 2140 90 78 HDPE MI 12g/10min Normal 128 109 2600 2150 35 30 9002-88-4 melting temperature; HDPE MI 2g/10min Normal 130 119 2560 2090 38 33 Phthalic anhydride 85-44-9 Hermetic 133 207 1925 2320 97 83 2-Chlorobenzoic acid 118-91-2 Hermetic 142 127 1390 1670 61 53 d-Mannitol 69-65-8 Normal 169 269 1700 2400 120 103 • Salt hydrates dehydrate severely in their T melt Δ H fusion Cp s Cp l E density Δ T Water Inorganic Melts CAS Lid melting point, also requiring a enclosed °C kJ/kg J/kg.K kWh/m 3 for 1m 3 system for thermal storage; Ba(OH) 2 -(H 2 O) 8 12230-71-6 Hermetic 82 241 1346 2445 151 130 Mg(NO 3 ) 2 -(H 2 O) 6 13446-18-9 Hermetic 93 100 2500 3100 56 48 MgCl 2 -(H 2 O) 6 7791-18-6 Hermetic 120 142 2000 2400 69 59 • All inorganic eutectics tested showed m/m T melt Δ H fusion Cp s Cp l E density Δ T Water Eutectic Melts Lid % °C kJ/kg J/kg.K kWh/m 3 for 1m 3 excellent thermal cycling properties; LiNO 3 -KNO 3 33-63 Stitched 128 135 1070 1430 82 71 "+18% NaNO3" 30-18-52 Stitched 127 167 1450 2030 104 90 Color Code LiNO 3 -KCl 58-42 Stitched 169 141 1430 1780 88 76 "+ 5% NaNO3" 53-5-42 Stitched 167 152 1530 1970 95 82 Discarded "+ 24% NaNO3" 42-24-34 Stitched 155 54 2120 1442 40 35 Poor thermal Cycling LiNO 3 -NaNO 3 48-52 Stitched 195 142 1780 3150 99 85 "+1% LiCl" 47-1-52 Stitched 193 118 1780 2810 85 73 Less Promising "+6% LiCl" 45-6-49 Stitched 195 210 1450 2250 137 118 Promising KNO 3 -NaNO 2 56-44 Stitched 142 45 2030 2485 38 33 Most Promising KNO 3 -NaNO 3 -NaNO 2 56-44 Stitched 144 76 2210 1550 54 46

Future Work • Thermal Cycling of promising organics near their melting point (+- 20C); • Development of a small scale prototype for higher volume testing; • Sell-and-tube; • Preparation of Chloride eutectics and novel nitrite eutectics; • Continuous research on • Tube in tank; nitrate eutectics: • Adition of other salts; • Corrosion tests of proven samples;