Food Processing Chillers. The global demand for industrial process cooling remains at a steady high. Reliability and minimal downtime are key to consistent and profitable industrial and commercial processes.
This article will consider the best methods to attain the optimal temperatures required to operate production processes in the metal finishing, medical, brewing, and agricultural industries. So, how does a chiller work? The process works in a loop, but we will start where the cooling medium interfaces with your process equipment.
The gaseous refrigerant is then circulated to a condenser which expels the heat through evaporative condensation or a cooling tower. This heat exchange condenses the cooling medium back into a cooler liquid that is sent back to process heating source to begin the cycle again. The type of coolant utilized in a chiller is based on process needs and cost considerations. The most popular coolants used are either water or a mixture of water and another substance with suitable heat conduction properties - like glycol compounds.
The use of water as chiller fluid is an economical one as in most cases the water can be easily sourced with minimal costs. Alternatively, purified deionized water, reverse osmosis water can be used in a water-based chiller to achieve a higher cooling efficiency.
Glycol based coolants are either composed of ethylene glycol or propylene glycol. While these two variants have similar physical properties, they should never be mixed. The major advantages which glycol coolants confer are an improved resistance to corrosion as well as antifreeze properties. Using a glycol-water mix as a chiller coolant has various benefits over the use of plain water as a chiller fluid. These advantages are due to its unique physical properties which include a lower freezing point than water.
When a glycol-water mixture is altered, the freezing point of the coolant also changes. In these thermal conditions, a water coolant will freeze and obstruct chiller circulation while diminishing overall efficiency.
By contrast, utilizing a glycol-based chiller will take advantage of its antifreeze properties ensuring the coolant remains in a desirable fluid state. Both glycol and water chillers can be used to satisfactorily dissipate the heat being generated by your production process.
The fundamental difference between both chiller types lies in variations in their freezing points as well as their heat conduction capacities. Pure glycol or a mix of glycol and water has a much lower freezing point than that of pure water.
By implication, glycol-based chillers are better suited to low-temp environments. Propylene glycol is non-toxic and so sees use in a wide variety of consumables, such as cosmetics and oral hygiene products as a preservative and moisture-retaining agent and HVAC systems. HVAC Cooling systems can benefit from the addition of glycol because of how it interacts with water. The freezing point of water is 32 degrees Fahrenheit; however, by mixing glycol with water, its freezing point can be reduced to as low as degrees Fahrenheit.
This serves a number of uses, the most obvious of which is that it helps to prevent pipes from freezing in cold weather. The low temperatures achievable through the use of glycol are also beneficial in cooling systems, which can remain highly chilled at a lower temperature than would be possible using water alone.
This is why glycol cooling systems are becoming more common than ever before. The first step in setting up a glycol cooling system is to establish a glycol chiller in a closed loop system. It also traps any moisture that may be introduced in the system in the event of a repair. The liquid filled pressure gauge allows you to monitor the leaving glycol pressure. This protects the system from over pressurization and also switches power to energize the compressor when cooling is called for.
This valve is adjustable but is normally set from the factory at 20psi. This senses discharge pressure and properly cycles the condenser fans as need to maintain head pressure to increase an efficient chiller operation. These fans cool the refrigerant by blowing air through the condenser coil. This is the cooling coil for the refrigeration system. This ultimately rejects the heat taken from the product being cooled by the chiller.
The refrigeration compressor takes refrigerant gas, compress to high pressure and sends out to the condenser to be cooled and condensed back into a liquid form. Both also help to guard against corrosion. Some grades of both types of glycol also help to prevent the growth of algae and bacteria within the chiller. Ethylene Glycol Ethylene glycol is a moderately toxic chemical that has a sweet taste and can be harmful if swallowed.
For this reason, it should not be used in potable water or food processing systems when leakage is a possibility. Ethylene glycol has more widespread use due to its lower purchase price. Industrial applications like ice rinks and factories requiring large volumes of the coolant find this to be the most economical choice of glycol.
Propylene Glycol Propylene glycol has a lower level of toxicity and is considered to be a food grade antifreeze. This type of glycol is safer to handle than ethylene and can be more easily disposed of.
Propylene glycol is commonly used in food Industry or in industrial refrigeration systems where people may come into contact with fluid.
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