Water Properties: Vaporization Heat vs. Temperature - Charts and Calculator (original) (raw)

The (latent) heat of vaporization (∆Hvap ) also known as the enthalpy of vaporization or evaporation, is the amount of energy (enthalpy) that must be added to a liquid substance, to transform a given quantity of the substance into a gas .

The enthalpy of vaporization is a function of the pressure at which that transformation takes place. The heat of vaporization diminishes with increasing temperature and it vanishes completely at a certain point called the critical temperature (Critical temperature for water: 373.946 °C or 705.103 °F, Critical pressure: 220.6 bar = 22.06 MPa = 3200 psi).

Online Water Heat of Vaporization Calculator

The calculator below can be used to calculate the liquid water heat of vaporization at vapor pressure at given temperatures.
The output heat is given as kJ/mol, kJ/kg, kWh/kg, cal/g, Btu(IT)/mol and Btu(IT)/lbm.

Note! Temperature must be within the ranges 0-370 °C, 32-700 °F, 273-645 K and 492-1160 °R to get valid values.

For vapor pressure - check tables below.

See Water and Heavy Water - for thermodynamic properties.
See also Water Boiling points at high pressure, Boiling points at vacuum pressure, Density, specific weight and thermal expansion coefficient, Dynamic and kinematic viscosity, Enthalpy and entropy, Ionization Constant, pKw , of normal and heavy water, Melting points at high pressure, Saturation pressure, Specific gravity, Specific heat (heat capacity) and Specific volume for online calculatores, and similar figures and tables as shown below.

heat_vaporization_C

heat_vaporization_F

Heat of vaporization for liquid water at saturation pressure at temperatures from 0 to 374 °C:

Water - Heat of Vaporization vs. Temperature

Temperature Vapor pressure Heat of vaporization, ∆Hvap
(°C) (kPa) (100*bar) (J/mol) (kJ/kg) (Wh/kg) (Btu(IT)/lbm )
0.01 0.61165 45054 2500.9 694.69 1075.2
2 0.70599 44970 2496.2 693.39 1073.2
4 0.81355 44883 2491.4 692.06 1071.1
10 1.2282 44627 2477.2 688.11 1065.0
14 1.5990 44456 2467.7 685.47 1060.9
18 2.0647 44287 2458.3 682.86 1056.9
20 2.3393 44200 2453.5 681.53 1054.8
25 3.1699 43988 2441.7 678.25 1049.7
30 4.2470 43774 2429.8 674.94 1044.6
34 5.3251 43602 2420.3 672.31 1040.5
40 7.3849 43345 2406.0 668.33 1034.4
44 9.1124 43172 2396.4 665.67 1030.3
50 12.352 42911 2381.9 661.64 1024.0
54 15.022 42738 2372.3 658.97 1019.9
60 19.946 42475 2357.7 654.92 1013.6
70 31.201 42030 2333.0 648.06 1003.0
80 47.414 41579 2308.0 641.11 992.26
90 70.182 41120 2282.5 634.03 981.30
96 87.771 40839 2266.9 629.69 974.59
100 101.42 40650 2256.4 626.78 970.08
110 143.38 40167 2229.6 619.33 958.56
120 198.67 39671 2202.1 611.69 946.73
140 361.54 38630 2144.3 595.64 921.88
160 618.23 37508 2082.0 578.33 895.10
180 1002.8 36286 2014.2 559.50 865.95
200 1554.9 34944 1939.7 538.81 833.92
220 2319.6 33462 1857.4 515.94 798.54
240 3346.9 31804 1765.4 490.39 758.99
260 4692.3 29934 1661.6 461.56 714.36
280 6416.6 27798 1543.0 428.61 663.37
300 8587.9 25304 1404.6 390.17 603.87
320 11284 22310 1238.4 344.00 532.42
340 14601 18507 1027.3 285.36 441.66
360 18666 12967 719.8 199.9 309.5
373.946 22064 0 0.0 0.0 0.0

Heat of vaporization for liquid water at saturation pressure at temperatures from 0 to 705 °F:

Water - Heat of Vaporization vs. Temperature

Temperature Vapor pressure Heat of vaporization, ∆Hvap
(°F) (psi) (Btu(IT)/mol) (Btu(IT)/lbm ) (cal/g) (kJ/kg)
32.2 0.0891 42.70 1075.2 597.33 2500.9
40 0.1219 42.52 1070.7 594.82 2490.4
50 0.1783 42.30 1065.0 591.67 2477.2
60 0.2564 42.07 1059.4 588.54 2464.1
70 0.3632 41.85 1053.7 585.39 2450.9
80 0.5073 41.62 1048.0 582.25 2437.7
90 0.6990 41.40 1042.4 579.09 2424.5
100 0.9506 41.17 1036.7 575.92 2411.3
110 1.277 40.95 1030.9 572.74 2398.0
120 1.695 40.72 1025.2 569.55 2384.6
130 2.226 40.49 1019.4 566.34 2371.2
140 2.893 40.26 1013.6 563.13 2357.7
150 3.723 40.02 1007.7 559.86 2344.0
160 4.747 39.79 1001.8 556.58 2330.3
170 6.000 39.55 995.87 553.26 2316.4
180 7.519 39.31 989.85 549.92 2302.4
190 9.350 39.07 983.76 546.54 2288.2
200 11.54 38.83 977.60 543.11 2273.9
210 14.14 38.58 971.35 539.64 2259.4
212 14.71 38.53 970.08 538.93 2256.4
220 17.20 38.33 965.02 536.12 2244.6
240 24.99 37.81 952.05 528.92 2214.5
260 35.45 37.28 938.64 521.46 2183.3
280 49.22 36.73 924.71 513.73 2150.9
300 66.6 36.15 910.21 505.67 2117.1
350 135 34.59 870.97 483.87 2025.9
400 247 32.82 826.41 459.12 1922.2
450 422 30.78 774.93 430.51 1802.5
500 680 28.37 714.36 396.87 1661.6
550 1044 25.48 641.56 356.42 1492.3
600 1541 21.93 552.09 306.72 1284.2
625 1849 19.41 488.64 271.46 1136.6
650 2205 16.95 426.81 237.11 992.8
675 2615 13.47 339.22 188.46 789.0
705.103 3196 0.00 0.00 0.00 0.0

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