An Introduction To Heat Exchangers And Thermal Fluids In The Food Processing Industry

The use of heat exchangers in the food industry has revolutionized and improved many food processing methods. Without a heat exchanger, dairy products would spoil almost immediately and pasta sauce's shelf life would be reduced to just a few weeks, and these are just two examples of how heat exchangers can improve the quality of food production and processing. Heat exchangers are used to perform a variety of functions including pasteurization, sterilization, ultra-high temperature processing (UTH) and other food processing needs to reduce or eliminate microorganisms so that food is sterile, has an extended shelf life, and is safe to eat Function.
Several studies have shown that heat exchangers can also reduce process energy requirements and, depending on the application, recover up to 50% of waste heat. Heat exchangers are most commonly used to heat or cool liquid foods prior to filling, drying, concentrating or packaging, and there are dozens of heat exchanger types currently on the market, all custom-made.

Heat exchanger
A heat exchanger is a device designed to transfer heat between two or more fluids (liquid, vapor or gas). Depending on the type of heat exchanger used, this transfer can be gas to gas, liquid to gas or liquid to liquid. If heat transfer occurs between two liquids, it is done through a solid separator to prevent mixing of the liquids. Design features such as construction, materials and components, heat transfer mechanisms, and flow configurations all affect the function and type of heat exchanger.
Thermal conditioning devices are currently used in many different industries such as wastewater management, refrigeration, petroleum refining, and nuclear power. Among them, heat exchangers that utilize fluid-to-fluid energy transfer must comply with the strict regulations of the US Food and Drug Administration (FDA) and the US National Sanitation Foundation (NSF) on the type of thermal fluid used to ensure that there is no environmental pollution or pose a health risk to consumers. At a basic level, all heat exchangers are designed according to the general principles of thermodynamics, but can also be individually tailored to suit individual user needs.

Conduction
The thermal processes used in heat exchangers in the food industry can be divided into two main heat transfer mechanisms, conduction and convection. Conduction is a heat movement in which materials of different temperatures are in direct contact, resulting in a temperature change. Temperature, on the other hand, is a measure of the average kinetic energy of the molecules that make up a particular material. Hotter materials will exhibit more molecular kinetic energy and exhibit higher temperatures. When a hotter object comes into contact with a cooler object, thermal energy transfer occurs between the two materials: the molecules of the cooler object will start moving faster and will become more energetic; while the hotter object will Begins to cool down as it loses energy. This heat transfer will continue between the two objects until thermal equilibrium is reached.
By using a heat transfer fluid in a heat exchanger, the liquid food temperature can be regulated and balanced. Heat-regulating fluids with low thermal conductivity, such as water or oil, have poor heat transfer capabilities, but we can use recent technologies, such as adding heat-conducting nanoparticles to these heat-transfer fluids, to enhance their thermal conductivity and promote better thermal conductivity. Transfer heat efficiently. Doing so allows the food to be heated to a higher temperature more quickly during processing and to reach thermal equilibrium.

Convection
Convection is the second method of heat transfer that heat exchangers use to regulate the temperature of materials. Convection is the heat transfer phenomenon that occurs during the flow of a fluid (liquid or gas). Most fluids expand when heated, become less dense and begin to rise. As a fluid cools, it becomes denser and begins to drop.
For example, when air in a room is heated, it rises to the ceiling, forcing higher-density cooler air to sink. The cold air is then heated up and displaces cooler, denser air near the ceiling. This process produces natural convection. Convection can also be forced or assisted, as in a hydronic heating system where hot water is pumped through pipes.

Conduction and convection describe the basic mechanisms of all heat exchangers. When selecting a heat exchanger for food processing, it is critical to consider additional factors such as the type of process the heat exchanger is undergoing (pasteurization, sterilization or dehydration), the How viscous the food or drink is and whether the solid or liquid contains fine particles.

In conclusion
The wide application of heat exchangers in the food processing industry not only enables food production and processing companies to process, package, transport and store food safely and reliably, but also enables these companies to save resources, energy and money.
In summary, when we design a heat exchanger that can effectively regulate the temperature of a fluid, it is important to consider the type of thermal fluid used as the regulator, and must also choose a liquid that is considered safe for incidental food contact by global regulations , such as HT1 food grade liquid. Because these food-grade liquids drive heat conduction and convection, not only to power the heat exchanger, but also to ensure the maximum health and safety of consumers.