Process and control today | Feeling the Heat: The Importance of Temperature Regulation in Heat Transfer
26/05/2022 Global Heat Transfer Ltd
Office temperature is an ongoing debate in businesses around the world. Employers often seek the optimum temperature to keep their employees comfortable and productive, but did you know that there is also an optimum air temperature for industrial facilities? This is Dave Dyer, Technical Sales Engineer at specialist in thermal fluids Global Heat Transfer, explores the importance of air temperature when operating heat transfer systems and how to regulate it effectively.
Temperature control is essential for any manufacturing environment – temperature changes can have a significant impact on processes, products and people. Some applications, such as food, chemical, plastics, or pharmaceutical manufacturing, require heating for production. Manufacturers in these industries must consider not only the impact of circulating fluid temperature on product quality, but also its impact on the entire installation.
Health and safety teams should monitor air temperature to ensure it does not negatively impact employee productivity or safety. Working at higher temperatures for long periods of time can lead to fatigue, increase the risk of illness while reducing personal productivity. Working near hot, uncovered equipment also increases the risk of injuries such as burns. In order to remain in compliance with health and safety legislation, companies must find ways to reduce the health and safety risks associated with working in installations using heat transfer fluids.
While employee safety is paramount, engineering managers must also monitor air temperature to ensure equipment remains operational – as equipment overheats, power consumption increases and the efficiency of the equipment decreases. Just as your desktop computer malfunctions when it overheats, electronic controls can fail when the temperature exceeds 40 degrees Celsius.
While a thermal fluid system is designed for indirect heat transfer, exceeding the intended operating temperature can negatively impact productivity. One area that can be particularly affected is the expansion tank, an essential component that allows hot thermal fluid with the space it needs to expand, which when heated can account for up to 20% system volume. To account for this and provide a sufficient safety factor, the expansion vessel should always be approximately one-third full when the system is cold. When the system is at full operating temperature, the level in the expansion tank where the oil reaches the atmosphere should not exceed 60 degrees Celsius. If the tank exceeds 60 degrees, the oil inside will oxidize, causing acid and carbon buildup (as shown in Figure 1). Over time, this will reduce the heat transfer efficiency of the equipment and could lead to costly downtime.
keep it covered
Investing in proper, properly installed insulation is the best way to regulate air temperature in the facility, control equipment temperatures, and better protect employees. The insulation ensures that the heat created during the manufacturing process does not heat up the installation elsewhere, allowing manufacturers to ensure that the air temperature is constant. Insulating parts of the system also means manufacturers can better regulate the temperature of equipment that must operate at specific temperatures, such as the expansion tank.
When choosing insulation for a heat transfer system, manufacturers must determine which material is best for the application. During its lifetime, a heat transfer fluid will degrade. The degradation process introduces by-products into the fluid, such as carbon that forms inside (as shown in Figure 2) and acid corrodes unseen parts of a thermal fluid system. If this continues unattended, small holes may appear in the coil (as shown in Figure 3), allowing fluid to leak, posing a fire hazard. Thermal oil would seep into porous insulation, increasing the risk of fire and other hazards, so using non-porous insulation, such as blown glass, works best in areas of the system where fluid could leak, including the flanges.
Although insulation is essential to improve the conditions of employees and equipment, it has additional advantages. Insulation prevents heat from escaping, improving heat transfer efficiency. Over time, manufacturers will find that less energy wasted through escaping heat will reduce energy consumption in the facility while reducing the carbon footprint of the process.
Finding the right temperature for a working environment is not easy. For example, in a 2018 survey by CareerBuilder, 46% of workers said their desk was either too hot or too cold. As offices continue to fight over the thermostat for employee comfort, it’s clear that manufacturing facilities need to take better steps to regulate temperature. Regulating air temperature can prevent health and safety hazards, reduce the risk of downtime, and improve equipment efficiency.
For more advice on insulating thermal fluid systems and other factors related to regulatory compliance, talk to the experts at Global Heat Transfer by visiting www.globalhtf.com/heat-transfer-management/.
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