As a result , in Austria the heat pump was used to dry salt in salt marshes .
In 1856 he recognized the principle of the heat pump while conducting experiments on the use of water vapor 's latent heat for the evaporation of salt brine .
In Austria the heat pump was used to dry salt in salt marshes .
In 1856 he recognized the principle of the heat pump while conducting experiments on the use of water vapor 's latent heat for the evaporation of salt brine .