Heat transfer always occurs from a region of high temperature to another region of lower temperature. Heat transfer changes the internal energy of both systems involved according to the First Law of Thermodynamics.
Cyperus esculentus (also called chufa sedge, nut grass, yellow nutsedge, tiger nut sedge, or earth almond) is a crop of the sedge family widespread across much of the world.It is native to most of the Western Hemisphere as well as southern Europe, Africa, Madagascar, the Middle East and the Indian Subcontinent.n Spain, C. esculentus is cultivated for its edible tubers, called earth almonds or tiger nuts, for the preparation of  horchata de chufa, a sweet, milk-like beverage. However, in most other countries, C. esculentus is considered a weed.
It is a drink drawn from tigernuts, water and sugar. The tigernut is a small and underground tuber with knot shape which comes from the roots of the juncia avellanada, called like that because of its shape similar to the hazelnut. The tigernut requires a loose and sandy ground for its cultivation and warm temperatures.The town of Alboraya, in Valencia (Spain) is one of the places that gathers the best conditions for its cultivation. A chilled tigernut milk is a typical drink in Spain during the summer season.The tigernut was already used in the Old Egypt and in Sudan. Arabic population began to cultivate it in the half of the Middle Ages. The tiger nut milk is not just a fresh drink, in comparison with any other soft drink, it is very healthy. - It contributes with level cholesterol reduction.