Solar Fluids

XCELTHERM® MK1

Chemically equivalent to DOWTHERM™ A. Recommended for Concentrated Solar Power Systems, PET production, Synthetic Fiber plants and many other applications that require a high temperature heat transfer fluid

Typical Properties
Engineering Properties
Safety Data Sheet
EU Safety Data Sheet
Contact HTF Representative
Terms and Conditions

Typical Properties

Key Operating Temperatures
Maximum Bulk Fluid Operating Temperature
Liquid Phase 750°F 400°C
Vapor Phase 750°F 400°C
Maximum Film Temperature 800ºF 427ºC
Crystallizing Point 53.6°F 12°C
Flash Point (PMCC)(ASTM D93)(min) 230°F 110°C
Flash Point (COC)(ASTM D92)(min) 255°F 124°C
Fire Point (ASTM D92)(min) 260°F 127°C
Autoignition Temperature (min) 1,150°F 621°C
Pumpability, at 300 mm2/s (cSt) 55.4°F > 13°C
Normal Boiling Point at 760 mm Hg 495°F 257°C
Physical Properties
Appearance Water-white to straw yellow liquid
Odor Aromatic
Composition Stable eutectic mixture of 73% Diphenyl Oxide and 27% Biphenyl
Average Molecular Weight 166 g/mol
Density, at 77°F/25°C 1,058 kg/m3 8.83 lbs/gal
Specific Gravity, at 25°C (77°F) 1.06
Moisture Content (max) 300 ppm
Critical Temperature 930.3°F 499°C
Critical Pressure 480.3 psia 3.31 MPa
Critical Density 20.4 lb/ft3 327 kg/m3
Critical Volume 0.0508 ft3/lb 3.17 L/kg
Kinematic Viscosity, at 104°F/40°C 2.48 cSt
Kinematic Viscosity, at 212°F/100°C 0.99 cSt
Coefficient of Thermal Expansion, at 392°F/200°C 7.317 x 10-4/°F 9.341 x 10-4/°C
Heat of Vaporization, at Maximum Use Temperature 123.3 BTU/lb 286.7 kJ/kg
Volume Contraction Upon Freezing 6.30%
Volume Expansion Upon Melting 6.66%
Heat of Fusion 41.9 BTU/lb 97.5 kJ/kg
Electrical Properties
Specific Resistivity, at 68°F/20°C 6.4 x 10 ohm-cm
Surface Tension in Air, at 77°F/ 25°C 36.6 dynes/cm
* Data represents typical laboratory samples and are not guaranteed for all samples

Engineering Properties

LIQUID PHASE*
Temperature Viscosity Density Specific Heat Thermal
Conductivity		 Enthalpy (Liquid)

Vapor
Pressure

ºF

ºC

cP

lb/ft3

kg/m3

BTU/lb-ºF

J/g-K

BTU/ft-hr-ºF

W/m-K

BTU/lb

J/g

psia

kg/cm2
53.6 12.0 5.708 66.8 1070.1 0.364 1.523 0.0792 0.1371 0.0 0.0 0.0001 –
60 15.6 4.961 66.7 1068.5 0.366 1.532 0.0790 0.1367 2.3 5.4 0.0001 –
80 26.7 3.470 66.1 1058.9 0.374 1.565 0.0784 0.1357 9.7 22.6 0.0004 –
100 37.8 2.629 65.5 1049.3 0.382 1.599 0.0778 0.1347 17.3 40.2 0.0010 0.0001
120 48.9 2.120 65.0 1041.3 0.390 1.632 0.0772 0.1336 25.0 58.2 0.0026 0.0002
140 60.0 1.727 64.4 1031.7 0.397 1.662 0.0765 0.1324 32.9 76.4 0.0059 0.0004
160 71.1 1.449 63.8 1022.1 0.405 1.695 0.0758 0.1312 40.9 95.1 0.0127 0.0009
180 82.2 1.245 63.3 1014.1 0.412 1.724 0.0750 0.1298 49.0 114.0 0.0254 0.0018
200 93.3 1.082 62.7 1004.5 0.420 1.758 0.0743 0.1286 57.4 133.4 0.0483 0.0034
220 104.4 0.936 62.1 994.8 0.427 1.787 0.0735 0.1272 65.8 152.9 0.0872 0.0061
240 115.6 0.822 61.5 985.2 0.435 1.821 0.0727 0.1258 74.5 173.1 0.1511 0.0106
260 126.7 0.730 61.0 977.2 0.442 1.850 0.0719 0.1244 83.2 193.3 0.2519 0.0177
280 137.8 0.654 60.4 967.6 0.449 1.879 0.0710 0.1229 92.0 213.9 0.4045 0.0284
300 148.9 0.591 59.8 958.0 0.157 1.913 0.0701 0.1213 101.1 235.1 0.6288 0.0442
320 160.0 0.537 59.2 948.4 0.464 1.942 0.0692 0.1198 110.3 256.3 0.9498 0.0668
340 171.1 0.490 58.6 938.8 0.471 1.971 0.0683 0.1182 119.6 277.9 1.3994 0.0984
360 182.2 0.449 58.0 929.2 0.478 2.001 0.0674 0.1167 129.0 299.8 2.0165 0.1418
380 193.3 0.414 57.4 919.5 0.485 2.030 0.0664 0.1149 138.6 322.0 2.8489 0.2003
400 204.4 0.383 56.8 909.9 0.492 2.059 0.0654 0.1132 148.3 344.6 3.9542 0.2780
420 215.6 0.354 56.1 898.7 0.499 2.088 0.0644 0.1115 158.1 367.4 5.3487 0.3761
440 226.7 0.330 55.5 889.1 0.507 2.122 0.0633 0.1096

168.3

391.1

7.1500

 0.5027
460 237.8 0.309 54.9 879.5 0.513 2.147 0.0622 0.1077 178.2 414.2 9.4113 0.6617
480 248.9 0.289 54.2 868.3 0.521 2.180 0.0611 0.1058 188.7 438.5 12.1631 0.8552
500 260.0 0.272 53.5 857.1 0.528 2.210 0.0600 0.1038 199.1 462.7 15.5617 1.0941
520 271.1 0.256 52.8 845.9 0.535 2.239 0.0589 0.1019 209.6 487.2 19.8169 1.3933
540 282.2 0.241 52.2 836.2 0.542 2.268 0.0577 0.0999 220.3 512.1 24.3956 1.7153
560 293.3 0.228 51.4 823.4 0.549 2.298 0.0565 0.0978 231.2 537.2 30.7227 2.1601
580 304.4 0.216 50.7 812.2 0.556 2.327 0.0553 0.0957 242.1 562.7 37.6331 2.6460
600 315.6 0.206 50.0 801.0 0.563 2.356 0.0540 0.0935 253.3 588.6 45.7286 3.2152
620 326.7 0.196 49.2 788.2 0.571 2.390 0.0527 0.0912

264.8

 615.4

55.0781

 3.8725
640 337.8 0.186 48.4 775.4 0.578 2.419 0.0514 0.0890 276.2 641.9 65.8004 4.6264
660 348.9 0.178 47.6 762.6 0.586 2.452 0.0501 0.0867 288.0 669.4 78.0639 5.4887
680 360.0 0.170 46.7 748.1 0.594 2.486 0.0488 0.0845 300.0 697.3 92.1431 6.4786
700 371.1 0.163 45.9 735.3 0.602 2.519 0.0474 0.0820 312.2 725.6 107.2571 7.5412
720 382.2 0.156 44.9 719.3 0.612 2.561 0.0460 0.0796 325.2 755.8 125.1955 8.8025
740 393.3 0.149 43.9 703.3 0.622 2.603 0.0446 0.0772

338.4

 786.4

145.5162

 10.2312
750 398.9 0.146 43.4 695.3 0.627 2.624 0.0439 0.0760 345.1

801.9

 156.6439

11.0136

VAPOR PHASE*
Temperature Viscosity Density Specific Heat Thermal
Conductivity		 Latent Heat Vap

Enthalpy**

ºF

ºC

cP

lb/ft3

kg/m3

BTU/lb-ºF

J/g-K

BTU/ft-hr-ºF

W/m-K

BTU/lb

J/g

BTU/lb

J/g
53.6 12.0 0.00571 – – 0.2331 0.9756 0.0103 0.0178

180.1

418.6

180.1

418.6
60 15.6 0.00577 – – 0.2361 0.9879 0.0103 0.0178

179.3

416.7

181.6

422.1
80 26.7 0.00598 – – 0.2443 1.0222 0.0103 0.0178

176.8

410.9

186.5

433.5
100 37.8 0.00619 – – 0.2525 1.0565 0.0104 0.0180

174.2

404.8

191.5

445.1
105 40.6 0.00625 – – 0.2545 1.0651 0.0104 0.0180

173.6

403.4

192.8

448.1
110 43.3 0.00630 – – 0.2566 1.0737 0.0104 0.0180

173.0

402.1

194.2

451.2
115 46.1 0.00635 – – 0.2586 1.0823 0.0104 0.0180

172.3

400.4

195.4

454.1
120 48.9 0.00641 – – 0.2607 1.0909 0.0104 0.0180

171.7

399.0

196.7

457.2
140 60.0 0.00662 0.0002 0.0025 0.2689 1.1252 0.0105 0.0182

169.2

393.2

202.1

469.6
160 71.1 0.00683 0.0003 0.0051 0.2771 1.1595 0.0106 0.0183

166.7

387.4

207.6

482.5
180 82.2 0.00704 0.0006 0.0099 0.2853 1.1938 0.0107 0.0185

164.2

381.6

213.2

495.6
200 93.3 0.00725 0.0011 0.0181 0.2935 1.2281 0.0108 0.0187

161.7

375.8

219.1

509.2
220 104.4 0.00746 0.0020 0.0319 0.3017 1.2625 0.109 0.0189 159.3 370.2 225.1 523.2
240 115.6 0.00767 0.0033 0.0535 0.3099 1.2968 0.0110 0.0190

157.5

 366.0

232.0

 539.1
260 126.7 0.00788 0.0054 0.0867 0.3181 1.3311 0.0111 0.0192

157.8

 359.8

238.0

 553.1
280 137.8 0.00809 0.0085 0.1355 0.3263 1.3654 0.0113 0.0196

152.7

 354.9

244.7

 568.8
300 148.9 0.00830 0.0128 0.2051 0.3345 1.3997 0.0114 0.0197

150.3

 349.3

251.4

 584.4
320 160.0 0.00851 0.0189 0.3028 0.3427 1.4340 0.0116 0.0201

148.0

 344.0

258.3

 600.3
340 171.1 0.00872 0.0273 0.4373 0.3509 1.4684 0.0117 0.0203

145.6

 338.4

265.2

 616.3
360 182.2 0.00893 0.0384 0.6152 0.3591 1.5027 0.0119 0.0206

143.2

 332.8

272.2

 632.6
380 193.3 0.00915 0.0529 0.8475 0.3673 1.5370 0.0121 0.0209

140.8

 327.2

279.4

 649.2
400 204.4 0.00936 0.0717 101486 0.3755 1.5713 0.0123 0.0213

138.5

 321.9

286.8

 666.4
420 215.6 0.00957 0.0954 1.5283 0.3837 1.6056 0.0126 0.0218

136.1

 316.3

294.2

 683.7
440 226.7 0.00978 0.1250 2.0025 03919 1.6400 0.0128 0.0222

133.7

 310.7

302.0

 701.8
460 237.8 0.00999 0.1620 2.5952 0.4001 1.6743 0.0130 0.0225

131.3

 305.1

309.5

 719.3
480 248.9 0.01020 0.2060 3.3001 0.4083 1.7086 0.0133 0.0230

128.9

 299.6

317.6

 738.1
500 260.0 0.01041 0.2600 4.1652 0.4165 1.7429 0.0135 0.0234

126.6

 294.2

325.7

 756.9
520 271.1 0.01062 0.3250 5.2065 0.4247 1.7772 0.0138 0.0239

124.2

 288.6

333.8

 775.9
540 282.2 0.01083 0.4010 6.4240 0.4329 1.8115 0.0141 0.0244

121.8

 283.1

342.1

 795.1
560 293.3 0.01104 0.4920 7.8818 0.4411 1.8459 0.0144 0.0249

119.4

 277.5

350.6

 814.7
580 304.4 0.01125 0.5970 9.5639 0.4493 1.8802 0.0147 0.0254

117.0

 271.9

359.1

 834.7
600 315.6 0.01146 0.7200 11.5344 0.4575 1.9145 0.0150 0.0260

114.7

 266.6

368.0

 855.1
620 326.7 0.01168 0.8620 13.8092 0.4657 1.9488 0.0153 0.0265

111.7

 259.6

376.5

 875.0
640 337.8 0.01189 1.0300 16.5006 0.4739 1.9831 0.0157 0.0272

108.3

 251.7

384.5

 893.6
660 348.9 0.01210 1.2200 19.5444 0.4821 2.0175 0.0160 0.0277

104.9

 243.8

392.9

 913.2
680 360.0 0.0131 1.4300 22.9086 0.4903 2.0518 0.0164 0.0284

101.5

 235.9

401.5

 933.2
700 371.1 0.01252 1.6800 26.9136 0.4985 2.0861 0.0168 0.0291

98.1

 228.0

410.3

 953.6
720 382.2 0.01273 1.9600 31.3992 0.5067 2.1204 0.0171 0.0296

94.7

 220.1

419.9

 975.9
740 393.3 0.01294 2.2900 36.6858 0.5149 2.1547 0.0176 0.0305

91.3

 212.2

429.7

 998.6
750 398.9 0.01305 2.4700 39.5694 0.5190 2.1719 0.0178 0.0308

89.6

 208.2

434.7

 1010.2