Impact Of Heat Transfer Fluids In Heating & Cooling Systems

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Those within the processing industries can often overlook the impact that heat transfer fluids used within heating and cooling systems can have upon their systems. System corrosion can cause issues for both installers and end users.

Due to the build-up of bacteria and scaling and resulting issues such as system leaks and failures, poor quality heat transfer fluids can have a negative impact on the longevity and reliability of systems.

Andrew Murray, head of sales and marketing at Kilfrost's Speciality Fluids Division, reviews things to consider when purchasing cooling and heating systems, the growing importance of environmental considerations and the need for improved industry standards.

Impact of Heat Transfer Fluids on the Processing Industries

By Andrew Murray, head of sales and marketing at Kilfrost's Speciality Fluids Division

Corrosion, bacteria and scaling have the potential to impact the life span and reliability of systems considerably. Corrosion can result in a greater need for maintenance and repairs, leading to downtime and reductions in productivity.

Glycol itself is not particularly corrosive, however when mixed with water to achieve frost protection, corrosion can become an issue. As a result, it is important to choose a heat transfer fluid that has advanced glycol inhibitors. Inhibited glycol-based heat transfer fluids mixed with water of a sufficient quality can limit corrosion within a system.

Despite the relatively low initial cost to the customer, a heat transfer fluid can quickly become the most expensive part of a cooling or heating system. Using a high quality fluid maximises a customer’s upfront investment in systems and can also reduce energy waste and extend the life of capital equipment.

Downtime, outages and the failure of heating or cooling systems can be extremely damaging within the processing industries. In these industries, time is money so system reliability is a key priority. Downtime needs to be kept to a minimum to avoid damage to productivity, loss of profits and resulting risks to a company’s reputation.

To ensure the safety and longevity of products at breweries, for example, they must be stored and processed at the correct temperature, so that product quality is maintained.

This is relevant across all food and beverage industries, where the safety of the end user cannot be compromised, meaning there is a vital requirement for effective and reliable cooling and refrigeration systems. In the pharmaceutical and chemical industries, processes need to be carefully temperature controlled to meet stringent regulatory requirements.

Industry standards

When system manufacturers and installers are tasked with specifying fluids, they will look at the thermal capacity, viscosity and density of a fluid. Ultimately, they are looking for the most efficient fluid.

The thicker a fluid is, the harder it is to pump round a system and therefore a larger pump is needed. This leads to a more expensive pump, higher running costs and greater energy use. As we move forward, thinner fluids will help improve pump efficiency, requiring less energy and smaller, more cost effective pumps.

As well as considering which heat transfer fluids are used, it is important that end users abide by an effective maintenance regime, checking heat transfer fluids regularly in heating and cooling systems.

Within the processing industries, there is a lack of formal guidance on the maintenance needed within systems. Fluids need to be checked for pressure and the presence of any foreign bodies which may indicate the breaking down of the fluid. The conditions under which fluids are transferred, stored, heated and applied can all have an impact on the fluid’s performance.

An international standard known as the ASTM D 1384 corrosion is playing an increasingly important role within the industry. All Kilfrost’s fluids adhere to this standard, but the standard has not been embraced by everyone in the industry and currently remains voluntary.

Greater adoption of the standard is needed, as any fluid can claim to contain corrosion inhibitors but without the presence of a mandatory test standard, it is difficult to gauge the extent of the protection.

The test works by assessing the impact of heat transfer fluids on a system. This involves analysing metals used in heat transfer systems, such as aluminium, iron, steel, brass, solder and copper after they have been immersed in an inhibited glycol/water mixture.

These tests are carried out over a period of four weeks under stringent conditions, at the end of that time the extent of any corrosion is determined by the weight of each metal. This gives system installers greater confidence by demonstrating how the fluid minimises the on-set of corrosion.

Environmental considerations for heat transfer fluids

Many companies in the processing industries are looking to lead the way in their sector, by managing their impact on the environment and choosing products that will reduce their carbon footprint.

Using a sustainable glycol in the manufacture of heat transfer fluids is set to have a dramatic impact on the carbon footprint and greenhouse gas emissions resulting from the processing industries.

It is possible to develop heat transfer fluids using corn-derived inhibited glycol, which is sustainable and biodegradable with low toxicity levels. This sees a significant reduction in carbon footprint, consuming 40 per cent less energy, from “cradle-to-gate” during the production of the base fluid.

Greenhouse gas emissions are also reduced by more than 40 per cent versus petroleum based propylene glycol fluids. Using non-toxic fluids is imperative in industries such as food and drink processing in order to safeguard the health of the end consumers, as well as staff working on the production and processing line.

It is also possible to use a bio-derived PDO based concentrate fluid which provides an alternative to monopropylene glycol based fluids. The use of this type of bio-PDO based fluid helps to minimise the risk to the environment, as well as those that may be exposed to the fluid. It also improves the longevity of the heating system thanks to its higher resistance to degradation.

Moving forwards

As we move forward, companies will continue to look for solutions that offer improved heating and cooling efficiency and enhance their low carbon footprint credentials.

Manufacturers and system installers will be striving to provide solutions that are reliable and that offer high performance levels. Consequently, the focus of heat transfer fluid providers will be to deliver innovative, more efficient, greener fluids that enable the heating and cooling industry to achieve optimum results, reducing corrosion, energy waste and improving the life span of systems.