Hydrogen (R702) Thermodynamic properties

Saturation tables by temperature and by pressure, superheated vapor table, p–h and T–s diagrams and constants of Hydrogen (H₂), computed with CoolProp. Any other state of Hydrogen, from any two properties, in the State Explorer or the Worksheet.

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Constants

Formula: H₂
Also known as: hydrogen, HYDROGEN, H2, R702
CAS: 1333-74-0
Molar mass: 2.0159 g/mol
Normal boiling point (1 atm): -252.78 °C (20.369 K)
Critical temperature: -240.01 °C (33.144 K)
Critical pressure: 1.2964 MPa
Critical density: 31.25 kg/m³
Triple point: -259.19 °C, 7.3578 kPa
Acentric factor: -0.219
Valid up to: 726.85 °C, 2000 MPa

Saturation table

By temperature: saturated liquid (f) and saturated vapor (g).

Saturated Hydrogen, by temperature
T °C	Psat kPa	vf m³/kg	vg m³/kg	hf kJ/kg	hfg kJ/kg	hg kJ/kg	sf kJ/(kg·K)	sg kJ/(kg·K)
-258	13.902	0.013156	4.3843	-45.272	455.88	410.61	-2.4835	27.607
-256	33.724	0.013477	2.0024	-29.487	456.7	427.22	-1.5222	25.108
-254	69.356	0.013852	1.0549	-11.818	453.28	441.46	-0.57546	23.094
-252	126.69	0.014299	0.61313	8.0398	444.67	452.71	0.36992	21.395
-250	211.88	0.014839	0.38165	30.513	429.8	460.31	1.3283	19.894
-248	331.28	0.015512	0.24903	56.22	407.2	463.42	2.3174	18.508
-246	491.47	0.016387	0.16729	86.151	374.59	460.74	3.3638	17.161
-244	699.48	0.017618	0.11344	122.19	327.52	449.71	4.5176	15.753
-242	963.64	0.019672	0.074887	169.26	254.31	423.57	5.9139	14.078

Saturation table by pressure

By pressure: saturated liquid (f) and saturated vapor (g).

Saturated Hydrogen, by pressure
P kPa	Tsat °C	vf m³/kg	vg m³/kg	hf kJ/kg	hfg kJ/kg	hg kJ/kg	sf kJ/(kg·K)	sg kJ/(kg·K)
10	-258.64	0.013064	5.868	-49.973	454.87	404.89	-2.797	28.551
20	-257.23	0.013274	3.1787	-39.418	456.64	417.22	-2.1117	26.576
30	-256.29	0.013427	2.2209	-31.889	456.83	424.94	-1.6605	25.435
50	-254.96	0.013665	1.4121	-20.51	455.5	434.99	-1.0267	24.008
100	-252.83	0.014105	0.75962	-0.44679	448.91	448.47	-0.02104	22.066
200	-250.24	0.014768	0.4028	27.665	431.95	459.62	1.2123	20.066
300	-248.47	0.01534	0.27424	49.884	413.27	463.16	2.0825	18.826
500	-245.91	0.016435	0.1643	87.667	372.77	460.44	3.4144	17.098
1000	-241.76	0.020045	0.070781	176.36	242.14	418.5	6.1179	13.831

Diagrams

p–h diagram of Hydrogen, with isotherms

T–s diagram of Hydrogen, with isobars

Superheated vapor table

At each pressure, from its saturated vapor (Sat.) to higher temperatures.

Superheated Hydrogen at 10 kPa (Tsat -258.64 °C)
T °C	v m³/kg	u kJ/kg	h kJ/kg	s kJ/(kg·K)
Sat.	5.868	346.21	404.89	28.551
-255	7.4019	369.24	443.26	30.911
-250	9.4887	400.48	495.37	33.447
-245	11.566	431.59	547.25	35.477
-240	13.638	462.65	599.03	37.17
-235	15.708	493.67	650.75	38.623
-230	17.775	524.69	702.44	39.896
-225	19.842	555.71	754.13	41.03

Superheated Hydrogen at 20 kPa (Tsat -257.23 °C)
T °C	v m³/kg	u kJ/kg	h kJ/kg	s kJ/(kg·K)
Sat.	3.1787	353.65	417.22	26.576
-255	3.6577	368.03	441.18	27.985
-250	4.7144	399.61	493.9	30.551
-245	5.7607	430.91	546.12	32.593
-240	6.8021	462.09	598.13	34.294
-235	7.8404	493.2	650.01	35.752
-230	8.8769	524.28	701.82	37.028
-225	9.9121	555.36	753.61	38.163

Superheated Hydrogen at 50 kPa (Tsat -254.96 °C)
T °C	v m³/kg	u kJ/kg	h kJ/kg	s kJ/(kg·K)
Sat.	1.4121	364.39	434.99	24.008
-250	1.8488	396.93	489.37	26.654
-245	2.2772	428.82	542.68	28.74
-240	2.7001	460.39	595.4	30.463
-235	3.1198	491.79	647.78	31.935
-230	3.5377	523.08	699.96	33.221
-225	3.9543	554.31	752.03	34.362

Superheated Hydrogen at 100 kPa (Tsat -252.83 °C)
T °C	v m³/kg	u kJ/kg	h kJ/kg	s kJ/(kg·K)
Sat.	0.75962	372.51	448.47	22.066
-250	0.89193	392.14	481.34	23.582
-245	1.1154	425.24	536.78	25.751
-240	1.3325	457.52	590.77	27.517
-235	1.5462	489.4	644.02	29.014
-230	1.7579	521.05	696.83	30.315
-225	1.9683	552.55	749.38	31.467

Superheated Hydrogen at 200 kPa (Tsat -250.24 °C)
T °C	v m³/kg	u kJ/kg	h kJ/kg	s kJ/(kg·K)
Sat.	0.4028	379.06	459.62	20.066
-245	0.53319	417.59	524.22	22.612
-240	0.64812	451.57	581.19	24.476
-235	0.75911	484.53	636.35	26.026
-230	0.86787	516.92	690.5	27.36
-225	0.97525	548.99	744.04	28.534

Superheated Hydrogen at 500 kPa (Tsat -245.91 °C)
T °C	v m³/kg	u kJ/kg	h kJ/kg	s kJ/(kg·K)
Sat.	0.1643	378.29	460.44	17.098
-245	0.17706	388.06	476.59	17.681
-240	0.23542	431.54	549.25	20.065
-235	0.28601	468.9	611.9	21.827
-230	0.33349	504.03	670.77	23.278
-225	0.37926	538.01	727.64	24.525

Superheated Hydrogen at 1 MPa (Tsat -241.76 °C)
T °C	v m³/kg	u kJ/kg	h kJ/kg	s kJ/(kg·K)
Sat.	0.070781	347.71	418.5	13.831
-240	0.091224	383.27	474.5	15.573
-235	0.12658	438.25	564.83	18.123
-230	0.15476	480.43	635.19	19.859
-225	0.18041	518.57	698.98	21.258

Enthalpy and entropy are measured from Hydrogen's own reference state (CoolProp's default). The textbooks' refrigerant tables use ASHRAE's: in the Worksheet, write reference ASHRAE.