Cooling of production halls in food industry

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1. OBJECTIVE


In several food industries, heat must be removed from production halls where heat-sensitive food is being processed in order to maintain high food quality. Depending on the type and the size of the industry, large amounts of heat can be removed.


2. FIELD OF APPLICATION


Cooling of production halls can be applied in the food industries where the product is heat-sensitive, such as dairies, meat, beer, wine and fish industries.


3. DESCRIPTION OF TECHNIQUES, METHODS AND EQUIPMENT


Cooling of production halls can be achieved in different ways, depending on the cooling needs of the unit. Conventionally, air conditioning units are used to decrease the temperature level of the production halls.


4. COMPETITIVE TECHNOLOGIES AND ENERGY SAVING POTENTIALS


a) Changes in the process
  • Absorption cooling: (Galitsky et al. Improving Energy Efficiency in Pharmaceutical Manufacturing Operations -- Part II: HVAC, Boilers and Cogeneration, Lawrence Berkeley National Laboratory, publication number LBNL 60288 Part 2)
Adsorption cooling utilizes the capacity of certain substances to adsorb water on their surface, from where it can be separated again with the application of heat. Adsorption cooling units can utilize waste heat from a variety of processes, where for standard refrigeration units, electricity would be required. These systems do not use ammonia or corrosive salts, but use silica gel (which also helps to reduce maintenance costs). Adsorption units were originally developed in Japan and are now also marketed in the United States.


Cooling food.jpg

Figure 1: Typical absorption cooling cycle (LITERATURE: http://lorien.ncl.ac.uk/ming/cleantech/refrigeration.htm)


  • Use of magnetocalorific materials:
    (LITERATURE:
    Goho, A. (2004) Cool magnet: a little bit of iron gives magnetic refrigeration a boost.
    Engelbrecht, K. L., (2005) A Numerical Model of an Active Magnetic Regenerative Refrigeration System, Thesis, Mechanical Engineering, University of Wisconsin – Madison)
To make refrigerators and air conditioners more energy efficient, several research groups around the world are developing magnetic-refrigerant materials. According to Goho (2004), magnetic-cooling systems could also be less polluting than current systems because they wouldn't use environmentally harmful chemicals, such as ammonia or chlorofluorocarbons.
When a magnetic-refrigerant material is exposed to a magnetic field, the field forces the spins of electrons in the material to align. As a result, the material heats up. Removing the field permits the electrons to relax into less-ordered states, and the material cools down. By cycling the material through these hot and cold states and venting away the heat, the system can generate an overall cooling effect (Goho 2004).
Researchers at the Department of Energy's Ames (Iowa) Laboratory and the Astronautics Corporation of America in Madison, Wis., have created a prototype magnetic refrigerator that operates at room temperature (Weiss 2002).
In 2005, studies by the University of Wisconsin predicted that magnetic refrigeration systems can operate more efficiency than current baseline vapor compression systems - if the regenerator is adequately large. According to Engelbrecht et al. (2005), the challenge now is to find more advanced magnetocaloric materials that are economical and allow design of more compact regenerator beds.
  • Use of electrocalorific materials: (Northwest Food Processors Association)
A new emerging cooling technology is based on the electrocaloric effect, whereby an electric field is cyclically applied to a paraelectric solid to cause heating and cooling. Analogous to magnetic refrigeration, which cyclically applies a magnetic field to a paramagnetic solid to cause heating and cooling (the magnetocaloric effect), a new technology is based on the electrocaloric effect, whereby an electric field is cyclically applied to a paraelectric solid to cause heating and cooling. The key difference between the two approaches is that large electrical fields are much easier and less expensive to produce than magnetic fields. If advantages can be confirmed through continued research and development, industry will once again have the opportunity to substantially reduce energy consumption by refrigerators and freezers.
CeramPhysics, of Westerville, Ohio, has successfully replicated the work performed in Russia and is entering into a series of proprietary experiments designed to identify one or more alternate ceramic compositions with an electrocaloric effect larger than that of the composition used in the Russian research. The technology is in the conceptual stage of new product development.
The energy-savings potential associated with this research is dramatic. According to the US Electric Power Research Institute, reducing the electrical consumption of US’s refrigerators and freezers by just 4.2 percent would save an estimated 479 million kWh—the equivalent of an average base-level power plant. At this rate, improving refrigerator and freezer energy efficiency by 50 percent would save 12 new base-level plants.
b) Changes in the energy distribution system

No information is available.


c) Changes in the heat supply system

No information is available.


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