Andrew Murrayassesses the specific requirements of the processing industries and discusses the impact of heat transfer fluids on the overall longevity of cooling systems
The Lindesnes Brygghus micro-brewery in Norway had a requirement for an effective and reliable cooling and refrigeration system, to ensure the safety and longevity of its products, which must be stored and processed at the correct temperature.
There are a number of factors for breweries and other companies in the food and drink processing sector to consider when choosing cooling systems.
Any heat transfer fluid used within the system needs to have low toxicity to ensure product safety and the wellbeing of those working in the processing plant, along with the safety of customers.
In the processing industries, time is money. Systems need to be reliable and there is a requirement to keep maintenance to a minimum.
The production line needs to be subject to minimal downtime. Poor quality fluids can increase the need for regular maintenance and, in some cases, expensive repairs due to leakages or system failures.
Breweries need to be confident that the right volume of beer can be supplied on time while ensuring optimum quality and value against overhead.
Breweries require a system that can provide them with longevity, in order to maximise their upfront investment.
Heat transfer fluids can have a considerable impact on the lifespan and reliability of a heating or cooling system.
While glycol-based fluids are not particularly corrosive in concentrate form, when they are mixed with water to achieve the required frost protection, corrosion, bacterial growth and scaling can become an issue for the system installer, as well as the end-user.
An inhibited glycol is needed that, when mixed with water of sufficient quality, can improve the reliability and effectiveness of systems.
Companies in processing industries are increasingly looking to reduce their carbon footprint. The sustainability of a product is therefore playing a more important role when selecting a cooling system. It is important to consider the full lifecycle of the fluid, when assessing the impact that heat transfer fluids have on the environment.
It is possible to develop heat transfer fluids using corn-derived inhibited glycol, which is sustainable and biodegradable with low toxicity levels, providing an alternative to petroleum derived propylene glycol-based heat transfer fluids.
In addition to the more direct benefits to the end-users and system installers/manufacturers, the use of a corn sugar-derived glycol sees a reduction in carbon footprint, consuming 40 per cent less energy during the production of the base fluid and reducing greenhouse gas emissions by more than 40 per
cent versus petroleum-based propylene glycol fluids.
The focus of providers of heat transfer fluids will be to deliver innovative, more efficient, greener fluids that enable the heating and cooling industry to achieve optimum results and reduce energy waste.
Efficiency, reliability and safety
When establishing its production facilities, Lindesnes Brygghus engaged with Energy Rent AS, a company specialising in refrigeration and process cooling, to find a cooling system and heat transfer fluid that would ensure its efficiency, reliability and longevity.
Kilfrost’s CooltransSustainCTS fluid was selected.
This is a bio-derived propane 1,3 diol-based (bio-PDOTM) concentrate fluid manufactured from corn-sugar derived glycol, meaning it is both sustainable and biodegradable.
As the heat transfer fluid is used in an indirect cooling process, with potential risk of contact with beverages, it was imperative that the fluid was non-toxic, non-hazardous and free from carcinogenic, mutagenic and reprotoxic (CMR) additives.
A bio-PDOTM based heat transfer fluid offers specific performance advantages over the use of a petroleum-derived propylene glycol-based transfer fluid. Compared with a propylene glycol-based fluid, while providing the same level of freeze protection, Bio-PDOTM fluid can offer up to 33 per cent lower viscosity at -20 deg C.
This vastly improved low-temperature viscosity profile translates into improved hydraulic performance and lower pressure drops in the system.
For example, a 40 per cent v/v solution of a propylene glycol-based fluid requires up to 2.4 times more pumping energy than a 40 per cent v/v solution of Kilfrost’s CooltransSustainCTS at -10 o C.
In addition to the significant improvement in low temperature hydraulic performance, CooltransSustainCTS also provides significant higher thermal stability, being up to four times more resistant to oxidative degradation than a standard propylene glycol-based fluid.
To ensure the quality of heat transfer fluids, the industry is turning its attention to the ASTM D1384-05 corrosion test standard.
Products that meet this standard have been proven to present minimal risk of system corrosion, giving installers and end-users of systems a framework of reference and peace of mind.
Andrew Murray is senior manager, speciality fluids division, Kilfrost