Process cooling in hot climates
Design and operational challenges in refrigeration systems
Susheel Moudgil Dubai Natural Gas Company Limited
C ooling is essential in the process industry to con- trol temperatures during chemical reactions, sepa- ration processes, and the operation of equipment. Depending on the application, the cooling medium can be air, cooling water or refrigerant. Cooling from air is achieved by using fin-fan air coolers, where air is blown over the finned tubes carrying the fluid. In a cooling water network, cold water absorbs heat from process streams via heat exchang- ers and subsequently rejects this heat to the atmosphere through evaporation in a cooling tower. Refrigerant cooling involves the use of a working fluid (refrigerant) that absorbs heat during evaporation at low pressure and releases it during condensation at high pres- sure. The selection of a cooling medium is dependent on the heat load, target temperature, water availability, weather, and economics. Table 1 summarises the general considera- tions for selecting a cooling medium. Cooling poses a major challenge for oil and gas plants in the Middle East region, especially during the hot sum- mer months. Ambient temperatures frequently exceed 110ºF-120ºF, thereby greatly reducing the effectiveness of fin-fan coolers. In addition, high wet bulb temperatures during humid conditions impair the performance of cooling towers, which rely on evaporative cooling. Many facilities rely on desalinated or treated water, which is expensive and lim- ited in supply. This often restricts the availability of make-up water for cooling towers, pushing plants to operate under constrained conditions. At the same time, overall cooling
demand normally peaks during summer due to elevated ambient heat loads. In response to the declining performance of conventional cooling systems under extreme ambient conditions, many oil, gas, and petrochemical facilities in the hotter climate zones are increasingly considering refrigeration-based cooling systems as a reliable alternative. Unlike air or water-based cooling, refrigeration, if designed for hot weather, can oper- ate independently of ambient temperature to a large extent, making it particularly effective in regions where summer temperatures regularly exceed 110°F. This approach is gaining attention in critical applications where stable temperature control is essential, such as gas compression units, hydrocarbon recovery systems, and low-temperature separation processes, where air or cooling water systems may fall short. While refrigeration systems involve higher capital investment and energy consumption, their ability to deliver better performance under extreme conditions can justify the costs in high-value operations. The following discussion further addresses this critical need by detailing the specific impacts of extreme heat on refrigeration system components and offering recommenda- tions for their robust design and efficient operation in such demanding environments. Typical process scheme Hydrocarbons, such as propane, propylene and butane, are increasingly used as natural refrigerants in industrial and
Comparison of cooling mediums for process cooling
Cooling medium Fin-fan air cooler
Advantage
Limitations
• No water required
• Efficiency decreases in hot weather • Outlet temperature depends on air
• Lower operational cost
• Simple to operate and maintain
temperature and humidity
• Environment friendly
• Requires large installation area • High noise levels • Mechanical wear of belts/fans/motor issues
Cooling tower
• High heat transfer efficiency
• High water consumption • Requires water treatment • Outlet temperature depend on
(using cooling water circulation)
• Compact
• Lower achievable temperature than
fin-fan coolers
wet bulb temperature
• Widely used and reliable
Refrigerant cooling
• Can be designed to achieve very
• High energy consumption
low temperatures
• Higher capital and maintenance cost
• Precise temperature control • No water required
Table 1
93
PTQ Q4 2025
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