Salz-Alkoholmischungen für die Latentwärmespeicherung

The medium contains alkali earth hydroxide(s) (I), esp. (I) hydrate(s), polyhydric alcohol(s) (II) and opt. other additive(s). (I) is pref. Ba(OH)2.8H2O (IA) and/or Sr(OH)2.8H2O. (II) is a di- to hexa-hydric, pref. a tri-, tetra- and/or hexa-hydrix alcohol; esp. a spherical mol., partic. pentaerythritol (IIB) and/or pentaglycerol, a sugar alcohol, partic. meso-erythritol, mannitol and/or dulcitol, or meso-inositol (a ring mol.). The medium may also contain metal salt(s) (III) of satd. aliphatic monocarboxylic acid(s), pref. an alkali(ne earth), esp. Na, salt of a 1-3C acid, pref. acetic acid, esp. Na acetate and partic. Na acetate trihydrate. The medium contains at least 40, (at least 50 mole.-% (I) 0.1-60, (5-50) mole.-% (II) or (II) + (III). It has a m.pt. in the 50-80, (60-75) deg. C range and enthalpy of melting of min. 400, (min. 450) MJ/m3. USE/ADVANTAGE - The medium is used in heat stores, pref. in vehicles esp. in the engine start-up and/or warm-up phase (claimed) and is also useful e.g. cooling medium for industrial plant, solar appts. and warm water prepn. and heating plant. It has high heat storage properties and is based on environmentally-compatible components. In an example, a storage medium for a vehicle contained 90 mole.-% (IA) and 10 mole.-% (IIA). These components form a eutectic with a m.pt. of ca. 65 deg. C.. The over-eutectic mixt. has a small eutectic peak at 65 deg. C and melting range with main m.pt. at 72 deg. C.. the specific storage capacity was 259 kJ/kg, (495 MJ/m3). More (IIA) could be added, giving a more nearly or purely eutectic mixt., if the mixt. was used with a diesel engine, having a lower operating temp. than a petrol engine, althrough this caused some redn. in the enthalpy of melting.