Direct Heat Exchangers in the Food Industry

Abstract

Heat refers to a type of energy as the molecules of a substance move in lockstep. The absolute temperature is proportional to the substance’s mean kinetic energy per mol ecule. Because of the temperature difference among different materials, thermal energy starts to move and transfer from one to another. The spontaneous, irreversible flow of heat from hotter (higher temperature) substances to the colder (lower temper ature) substances is known as heat transfer. This field of study focuses on the analysis and quantification of heat transfer. The science of heat flow and its relationship to mechanical work is known as thermodynamics. The principle of energy conservation is well known as the first law of thermodynamics. Except in subatomic processes, energy cannot be created or destroyed and it can only be transformed from one form to another. The terms “work” and “heat” are interchangeable. Unless there is an energy storage component, the energy output must match the energy input. Moreover, the second law of thermodynamics is that heat transmission may only occur in one direction, which is from a hotter substance to a colder one or from a higher to a lower energy state, just like water flow which takes place only downhill. Heat does not flow from a low-temperature substance to a high-temperature one spontaneously. A device can only provide heat in the reverse direction if it receives external energy. Any device or equipment that performs work must have an energy source and operation units, which means that energy must flow through the machine. However, only a portion of this flow may be converted into work (Savulescu, Sorin, & Smith, 2002).