Maslow's Hierarchy of Needs. Definition. Maslow's hierarchy of needs is a theory of motivation and personality developed by the psychologist Abraham H. Maslow (1908â1970). Maslow's hierarchy explains human behavior in terms of basic requirements for survival and growth.
When you use ice to cool the ingredients for ice cream, the energy is absorbed from the ingredients and from the outside environment (like your hands, if you are holding the baggie of ice!).
Absorption chillers, instead of using electricity (high. grade energy), use heat as energy source which is low. grade energy. The energy source may be gas or oil, or. hot water, or it may be waste heat as in exhaust gas from. an engine and steam.