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.
Tiger nuts are hard to find these days, but in the years after the Second World War, when food rationing was prevalent, tiger nuts along with carob pods had favoured import status, on account of their nutritional qualities.Nowadays they are eaten as an unusual snack, turned into a âmilkâ, or used as bait in fishing.iger nuts are popular in Spain where they are made into a drink, and most tiger nuts imported into the UK are Spanish. Keen gardeners can grow tiger nuts in the UK. Soak them first for a few days then plant them in the spring about 4cm down in recently disturbed soil in a sunny position.