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Longer Lasting Glycol Thermal Fluids, Cleaners, Biocides and Check Kits for GSHPS and ASHPS Launched


Sentinel’s answer to the ‘growing’ problems being experienced!

Leading water treatment specialist Sentinel has launched a unique range of products to address the problems increasingly being associated with the rapidly emerging renewable energy marketplace.

Following closely on the heels of the launch of a brand new and comprehensive range of products to service the emerging solar thermal heating system sector at the end of 2008, Sentinel has now launched an impressive new range of products aimed at the ground source heat pump and air source heat pump marketplace.

These systems commonly use a glycol-based thermal fluid to capture the available heat and transport it to the heat exchanger or thermal store.

It has become increasingly apparent as the marketplace for these systems has grown over the past couple of years in both the UK and continental Europe, that problems occur due to the progressive degradation of the glycol-based thermal fluid. Glycols will slowly break down due to the chemical action of either heat or light and this degradation occurs much more quickly in solar thermal systems where temperatures of over 200°C occur regularly.

If that wasn’t enough of a challenge to address, glycol can also be degraded in much cooler conditions by the action of bacteria, which use glycol as a food source.

Anyone who has been on site to witness the installation and commissioning of GSHP systems in particular, will be aware that these offer many opportunities for contamination of the system loop with bacteria from soil, insects, and contaminated flush water. Subsequently the temperature and a plentiful supply of glycol ‘food’, ensures rapid biological growth. This not only causes degradation of the glycol but also forms slimes and deposits which affect the circulation and the efficiency of the system. In severe cases, this may even cause blockages which are problematic and costly to sort out.

Whether broken down by chemical or biological action, degraded glycol takes on an unpleasant and distinctly unhealthy appearance. It progressively discolours and becomes thicker and more viscous. This makes it more difficult to pump. Pumps then have to work harder, to the point where this outweighs the energy efficiency of the system in the first place! The freezing point of the fluid also rises as it degrades, meaning a progressive lost of frost protection for the system. By this stage things are going rapidly downhill!

Sentinel recognised that in order to ensure efficient, reliable and cost effective operation, a new range of bespoke products was required for each type of system, including more robust thermal fluids that would last for significantly longer than the current options, flushing liquids to help remove fluids from existing systems, a sanitiser and biocide that would address the bacterial growth and test kits to check the system was in good condition.

The new range of products produced specifically for Ground Source Heat Pump systems includes Sentinel R500 Thermal Fluid, together with Sentinel R800 Cleaning and Flushing Fluid and Sentinel R700 Sanitiser and Biocide for correct cleaning and preparation of the ground loop during commissioning or fluid replacement.

For Air Source Heat Pump systems Sentinel provides R600 Thermal Fluid. The correct use of both R500 (GSHP) and R600 (ASHP) can be checked using the new Sentinel FrostCheck Test Kit. Correct use of Sentinel R700 Sanitiser and Biocide, which is used for cleaning and sterilisation of both GSHP and ASHP circuits or flush waters, can be checked using the new Sentinel R700 Test Kit.

The new thermal fluids developed by Sentinel are glycol-based, specifically designed to be highly efficient heat transfer fluids, but offering superior stability and life expectancy whilst being biodegradable.

R500 for GSHPs is supplied ready to use – so no need for dilution on site which can prove awkward in the volumes required and the space available. As well as providing effective frost protection to -22°C and corrosion inhibitors, it contains a biocide to prevent fouling.

R600 for ASHPs is supplied as an inhibited thermal fluid concentrate, suitable for use with all water hardnesses. Again it provides effective frost protection and controls corrosion and scale formation.

The R800 Cleaning and Flushing Fluid for GSHPs and ground loop circuits has been designed to provide a highly efficient cleaning and flushing fluid. It comes ready to use and non-foaming. It’s effective within one hour of circulation in the system, is effective at ambient temperature and can be used with a flushing machine.

R700 Sanitiser and Biocide for heat pump systems contains a stabilised biocide for use in the heat collector circuit of both GSHPs and ASHPs. These systems have been demonstrated to suffer from problems caused by the growth of organisms such as bacteria and fungi, causing the degradation of thermal fluids, blockages in pipework, manifolds, valves and heat exchangers, unpleasant smells and corrosion of heat exchangers and manifolds. Sentinel R700 kills bacteria and fungi, prevents the formation of slime forming bacteria, provides long lasting protection and can be used in systems that are or will be treated with R500 or R600.

Dr Paul Day and Dr Alan Marshall are part of the Sentinel team that developed these new products: “We could have simply looked at these emerging technologies and devised a ‘me too’ product range but we quickly became aware of the existing products’ shortcomings and consequently devised new products and protocols that more effectively respond to the technical challenges.

“The problem with the currently available thermal fluids is their alarmingly rapid rate of degradation – usually requiring replacement after two to three years but sometimes in as little as a few months – leading to an increase in the freezing point and a reduction in frost protection, alarming colour changes, increased viscosity of the fluid, making it harder to pump, deposits and blockages and a reduction in heat transfer capability – which rather defeats the object of the system in the first place.

“We developed our new thermal fluids to offer excellent thermal stability, increased service life and increased cost effectiveness and we’re confident we have developed an impressive response to the problems that were occurring.

“In addition, we’ve developed products to flush and clean GSHPs ands ASHPs and test kits to check the validity of the products, so we’re happy to launch this range of renewable technology products with confidence that, used correctly, they will alleviate the problems of premature fluid degradation and microbiological bacterial and fungal growth in these systems.”

Sentinel has applied for patents for many of the elements of the new range of products highlighting the truly unique nature of these new solutions for the industry.

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