Method and arrangement for saving energy in preparing hot water for household

DETAILED DESCRIPTION Having described my invention, I claim: 1.
An arrangement for saving energy in preparing hot water for households, comprising a heat insulated container with a thermostatically controlled electric heating element, which container is supplied with the water to be heated, characterized in that the lower part of the container is surrounded by an exteriorly heat insulated mantle with an inlet at the top of the mantle, for warm waste water from bathtub and shower, etc.
and an outlet for the warm waste water at the bottom of the mantle, which outlet is connected to a water trap at the outlet of which being at the level of the said inlet.
2.
An arrangement for saving energy in preparing hot water for households, comprising a heat insulated container with a thermostatically controlled electric heating element, which container is supplied with the water to be heated, characterized in that the lower part of the container is surrounded by two exteriorly heat insulated mantles, one above the other, the lower one having an inlet at the top of the mantle for warm waste water from bathtub and shower, etc.
, and an outlet for the warm waste water at the bottom of the mantle, which outlet is connected to a water trap the outlet of which being at the level of the said inlet, and in the upper mantle is by means of a circulation pump circulated by a heat transfer medium which is exposed to radiation from the sun.
3.
An arrangement for saving energy in preparing hot water for households, comprising a heat insulated container with a thermostatically controlled electric heating element which container is supplied with the water to be heated, characterized in that the lower part of the container is surrounded by two exteriorly heat insulated half cylindric adjacent mantles, of which the one has an inlet at the top of warm waste water from bathtub and shower, etc.
, and an outlet for the warm waste water at the bottom of the mantle, which outlet is connected to a water trap, the outlet of which being at the level of the said inlet, and the other mantle is by means of a circulation pump circulated by a heat transfer medium which is exposed to radiation from the sun