Both glycol and water chillers can be used to successfully eliminate the heat generated by the production process. The basic difference between both types of chillers in the variations in their freezing points as well as their heat conduction capacities. Pure glycol or a mix of glycol refrigeration systems and water or even ammonia refrigeration can have a much lower freezing point than that of pure water. Glycol based chillers are better suited to low temperature environments. However, water has a better ability to retain and conduct heat from an associated process than a glycol mixture. As a result, the efficiency of heat transfers for a water chiller would be higher than that of a glycol chiller. The operators should consider the ambient temperatures for the environment before picking the right chiller type.
How Glycol Refrigeration Systems Work?
Glycol chiller plant contains a refrigeration component and tubing that contains a glycol-water mixture as coolant. Chilled fluid from the refrigeration unit can be channelled through the piping associated with a thermal exchanger surrounding a heated process. Once the heat is absorbed from the associated process, the warm coolant is returned to the refrigeration unit for cooling. This process keeps repeating.
Types of Coolants Used in Chillers
You have to consider the needs and cost before you think of the type of coolant used in a chiller. The most popular coolants used are either water, ammonia or some other substances with suitable heat conduction properties like glycol compounds.
Water: Using water as a chiller fluid can be economical and in most cases, the water can be easily sourced with minimal costs. As an alternative, the purified water (deionized water, reverse osmosis) can be used in a water-based chiller to achieve great efficiency in higher levels of cooling.
Glycol: Glycol based coolants are composed of ethylene glycol or propylene glycol. These two variants have similar properties but they should not be mixed at all. The major advantages of glycol coolants are that they have an improved resistance to corrosion as well as antifreeze properties.
Ammonia: Ammonia based refrigeration systems can cost only 10 to 20 percent less to build than the one that uses CFCs as a narrow diameter piping can be used easily. Ammonia is a more efficient refrigerant than CFCs. Hence, an ammonia refrigerant requires less electricity that results in lower operating costs. It is safe for the environment and less expensive when compared to CFCs or HCFCs.
Ammonia refrigeration can be an attractive and feasible alternative for conventional HFC chillers when it comes to industries. The standardisation in safety regulations, simplified operation and maintenance procedures. Equipment and housing details, lower equipment costs etc. can help in wider use of natural refrigerant, ammonia.
On the other hand, Glycol refrigeration systems can reduce the freezing point of process fluid and make sure that it continues to flow at the operating temperature. Using inhibited glycol in the system would prevent corrosion and scale from forming. Also, it can prevent the growth of bacteria and algae on metals such as copper, steel, brass, cast iron and aluminium.