Feeling The Heat: Temperature Regulation In Heat Transfer

Dave Dyer, technical sales engineer at thermal fluid specialist Global Heat Transfer, explores the importance of air temperature when operating heat transfer systems and how to regulate it effectively.

By Dave Dyer

The temperature of the office is an ongoing debate in businesses globally. Employers often search for the optimal temperature to ensure their employees are comfortable and productive. But did you know there’s also an optimal air temperature for industrial facilities?

Temperature control is essential for any manufacturing environment — changing temperatures can have a significant impact on processes, products, and people. Some applications, such as food, chemicals, plastics or pharmaceuticals manufacturing, require heating for production. Manufacturers in these industries must consider not only how the temperature of circulating fluid will impact product quality, but how it will impact the entire facility.

Health and safety teams should monitor air temperature to ensure it does not negatively impact employee productivity or safety. Working in higher temperatures for longer periods of time can lead to fatigue, increasing the risk of illness while reducing personal productivity. Working around hot, uncovered equipment also increases the likelihood of injuries such as burns. In order to remain compliant with health and safety legislation, companies must find ways to reduce the health and safety risks of working in facilities with heat transfer fluids.

Hot Equipment

While employee safety is paramount, engineering managers should also monitor air temperature to ensure that equipment remains operational — as equipment overheats energy consumption increases and equipment efficiency decreases. Just like your office computer malfunctions when it overheats, electronic controls can fail when temperatures exceed 40 degrees Celsius.

heat transfer
Figure 1

While a thermal fluid system is built for indirect heat transfer, exceeding the intended operating temperature can negatively impact productivity. One area that can be particularly affected is the expansion tank, a critical component that allows hot thermal fluid with the space it needs to expand, which when heated can be up to 20 percent of system volume. To allow for this as well as provide a sufficient safety factor, the expansion tank should always be approximately one-third full when the system is cold. When the system is at full working temperature, the level in the expansion tank where oil hits the atmosphere should not exceed 60 degrees Celsius. If the tank exceeds 60 degrees, the oil inside will oxidize, leading to a build-up of acid and carbon (see 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 correct and properly installed insulation is the best way to regulate air temperature in the facility, control the temperature of equipment, and better protect employees. Insulation ensures that heat created in the manufacturing process does not heat up the facility elsewhere, enabling manufacturers to ensure the air temperature is consistent. Insulating parts of the system also means that manufacturers can better regulate the temperature of equipment that must operate at specific temperatures, such as the expansion tank.

heat transfer
Figure 2

When choosing insulation for a heat transfer system, manufacturers should consider what material best suits the application. During its lifespan, a heat transfer fluid will degrade. The degradation process introduces by-products into the fluid, such as carbon that forms inside (see figure 2 at right) and acid corrodes unseen parts of a thermal fluid system. If this continues without intervention, small holes can appear in the coil (see figure 3 below), allowing fluid to leak, posing a fire hazard. Thermal oil would soak into porous insulation, increasing the risk of fire and other hazards, so using a non-porous insulation, such as blown glass, works best in areas of the system where fluid could leak, including flanges.

heat transfer
Figure 3

Further Benefits

While insulation is key to improving conditions for employees and equipment, there are added benefits. Insulation prevents heat from escaping, improving heat transfer efficiency. Over time, manufacturers will find that less energy wasted from heat escaping will reduce energy usage in the facility while also reducing the carbon footprint of the process.

Finding the correct temperature for a work environment is not easy. For example, in a 2018 survey by CareerBuilder, 46 per cent of workers said their office is either too hot or cold. While offices continue to argue over the thermostat for employee comfort, it is clear that manufacturing facilities must take better action to regulate temperature. Regulating air temperature can prevent health and safety risks, reduce the risk of downtime, and improve equipment efficiency.

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Dave Dyer is a technical sales engineer at Global Heat Transfer, a thermal fluid specialist that provides heat transfer engineering assistance and thermal fluid supplies. Dave has worked in engineering, technical support and technical sales for almost 20 years. His knowledge of thermal fluid, hot oil and heat transfer process applications includes HSE regulatory compliance, troubleshooting system and fluid issues on-site and remotely. 

Since 2004 he has specified and deployed engineering solutions for thermal fluid / hot oil process applications in some of Europe’s largest manufacturing facilities and the largest heat transfer manufacturing facility in the UK. 

He delivers on-site training to engineering teams, health and safety professionals and operations personnel to help them proactively manage thermal fluid / hot oil and heat transfer systems to improve operational efficiency and safety and reduce system downtime for companies worldwide.

 His knowledge of heat transfer applications covers a range of sectors including; food and beverage, pharmaceutical, chemical, plastics, polymers, wood, metal finishing, composite materials, biofuels, oil and gas, asphalt, renewables and industrial manufacturing.