enthalpy Physics.
(ˈɛnθəlpɪ, ɛnˈθælpɪ)
[ad. Gr. ἐνθάλπειν to warm in, f. ἐν in + θάλπειν to heat.]
A thermodynamic property of a system: the sum of its internal energy and the product of its volume and the pressure exerted on it; usu. measured relative to an arbitrarily defined zero.
| 1927 H. Moss tr. Mollier's Steam Tables 3 The quantity E is known as the internal or intrinsic energy while the quantity H is termed the total heat, enthalpy or (sometimes) heat content. 1930 Engineering 8 Aug. 162/1 The calculation of the enthalpy, or heat contained in saturated air will show that most of the heat present..is the latent heat in the associated steam. 1950 Jrnl. R. Aeronaut. Soc. LIV. 73/2 This is the usual enthalpy-entropy diagram, drawn on the assumption of no internal losses or increase in entropy. Ibid. 76/1 Since there can be no loss in energy, the enthalpy levels of each of the points of the cycle diagram prior to the final expansion remain the same as for the ideal cycle. 1962 Engineering 23 Feb. 276/2 The total heat content (enthalpies) of the coolant gas at inlet. 1967 Condon & Odishaw Handbk. Physics (ed. 2) v. i. 5 In a change occurring at constant pressure..all the heat added to the system goes to increase the enthalpy. |