The perfect blend
Most industries strive for the same common goal – a reduction in costs to increase profitability. One of the ways Blended contributes to this for its clients is by offering in-house testing as a service. Technical Quality Manager, Ben France, provides insights as to why this is a unique benefit but also very necessary.
How pure is your refrigerant?
As standard, we verify the glycol percentage on all shipments prior to leaving the site. We also offer a suite of tests to our customers; the purpose of these tests is to detect potential system problems as early as possible, eliminating the need for costly shutdowns that may arise from system failures.
We also offer testing on ammonia to detect purity and to determine the type and quantity of contaminants using advanced spectroscopic equipment. This testing will provide the information you need to understand when it is your ammonia refrigerant that is causing your refrigeration plant to run inefficiently.
Testing and maintaining glycol-based heat transfer fluids
HVAC systems experience changes such as leaks and corrosion within their piping components that can ultimately affect the heat transfer fluid used within them. Observing these changes can significantly increase the effectiveness and longevity of the fluids.
A benefit of in-house laboratory testing at Blended is that pre-emptive actions can be taken before the point of costly system failure.
The tests we regularly undertake are:
Acidity (pH) levels
A common route of glycol decay is oxidation, this causes the formation of acidic chemicals which are corrosive. Under normal circumstances corrosion inhibitors will prevent corrosion from small amounts of acidic compounds.
Many corrosion inhibitors are most effective at basic pH levels and if the formation of these acidic compounds lowers the pH it can reduce the effectiveness of the corrosion inhibitor or in some cases stop it working entirely.
Measurement of the glycol pH allows the monitoring of the situation so preventative action can be taken if needed.
Determination of iron content
If corrosion is occurring inside your system, it can be accurately monitored via the iron content of the glycol. Most systems are built with steel and corrosion can be readily detected by an increase of iron content in the glycol mixture.
Our spectroscopic method allows for very accurate determination of the iron content in samples.
Review of conductivity
Dissolved solids may promote corrosion and can indicate that incorrect water is being used for the loading or top up of the system.
This measurement allows for determination for dissolved salts in the glycol mixture.
Refractometry
This provides an accurate measurement of glycol concentration within the system. Water is normally used to top up a system in case of fluid loss, which in turn reduces the concentration and therefore effectiveness of the system fluid.
This measurement is key to maintaining optimum glycol concentration levels and frost protection for your system.
Turbidity
This is a measure of how cloudy the glycol is. Most problems that can occur in your system, corrosion or otherwise will cause the glycol mixture to become cloudy.
Turbidity analysis measures the extent of contamination in your glycol from suspended solids.
Ammonia Presence Testing
Using our advanced spectroscopic equipment, it is possible to determine if the glycol has been contaminated with ammonia.
The presence of ammonia in system glycol is indicative of cross contamination between primary and secondary refrigerant.
Glycol testing in action
We have already had some success in testing secondary refrigerant solutions for our customers. In one case we were contacted about a system our customer had recently taken ownership of and they needed to understand the state of the system and the best way to start it up.
It was clear there was a problem as the sample of existing fluid was orange in colour immediately indicating that the system was rusting to some extent. Our iron test was able to quantify the levels of iron in the solution and it went above our standard grading scale which indicated a severe problem. If we had stopped here, we would have recommended an in-system flush with filtration and a top up of corrosion inhibitor. In reality we did a full suite of tests and found the glycol concentration was very low with refractometry, the conductivity was very high, and the pH was extremely low. This all pointed to the solution being completely compromised and as a result our customer completely emptied the system and was able to flush it with our Serviceblend PRE before starting it up with a fresh glycol solution. If our customer did not have access to testing capability it is possible, they would have assumed it was a rust problem and only topped up the corrosion inhibitor. With such a low pH this would likely have had no effect and the system would have continued to deteriorate leading to a costly shut down.
Value of glycol testing
Each of these tests individually shows part of the picture of the glycol solution running in your system but combined they allow a comprehensive understanding. This knowledge helps our customers understand problems in their glycol systems allowing for effective preventative actions to be taken. This increases the efficiencies of their systems and reduces downtime all of which contributes to lower running costs.
Ammonia testing in action
There is a great deal of value in laboratory testing of ammonia that is rarely accessed due to the logistical and safety challenges of working with anhydrous ammonia. Here at Blended we have bespoke sampling and testing equipment that allows us to safely perform gravimetric purity, water content and oil content analyses on anhydrous ammonia samples. Traditionally these testing methods are used at the ammonia manufacturing plant to validate the ammonia grade, following which there are few additional tests quality tests.
When in use as a refrigerant, the water content of ammonia is well recognised as an issue; the more water contamination that is present in the system, the higher the energy costs will be to achieve the same refrigeration temperatures.
The race against market volatility
Given the volatility in the energy market seen over the past 12 months, running a refrigeration plant as efficiently as possible has become even more important. Whilst the negative impact of contaminants in an ammonia refrigeration system is widely understood, it is not yet standard practice for the refrigeration industry to regularly test the ammonia in their system. When the water testing is coupled with gravimetric purity and oil analysis it is possible to gain a well-rounded picture of the state of the ammonia refrigerant in the system.
By implementing a regular testing regime, it is possible to verify the quality of the ammonia and understand the level and identity of contaminants present and also to track the changes over time. This in turn will allow an understanding of the root causes of such contamination, enabling early failure detection and preventive maintenance, which in turn will avoid costly breakdowns in terms of unplanned downtime, production/product losses and repairs. When this data is coupled with energy consumption data it will become possible for our customers to calculate the point it would make more sense economically to refresh their ammonia system charge as the energy savings begin to outweigh the cost of fresh refrigerant.
Examples in practice
In addition to providing information to customers on the quality of their ammonia, our laboratory tests have identified signs of other problems. In a recent examination a blue residue was found in the ammonia; after discussion with the customer, it became apparent there were 2 potential causes:
- This system used a blue glycol solution as secondary refrigerant, indicating that the heat exchanger between primary and secondary refrigerant may be failing and allowing the transfer of primary and secondary refrigerants across the heat exchanger.
- Ammonia reacts with copper forming cuprammonium ions which have a blue colour, this raised a concern that brass fittings may have been used on the plant. The ammonia would rapidly corrode these producing the cuprammonium ions, presenting a significant risk of containment loss.
Both options presented problems to our customer and prompted us to perform additional analyses, as a result of which we were able to confirm the presence of cuprammonium ions. We then informed the customer that brass had been used on their plant and they were able to act to rectify this problem.
Laboratory testing – endless benefits
These lab tests are giving our customers the information they need to run their plants as efficiently as possible while enabling them to understand where problems may be occurring and allow preventative maintenance which reduces the chance of unexpected shutdowns. Blended strongly recommend that testing of the ammonia on a 6 monthly cycle be included as part of the standard maintenance cycle for an ammonia refrigeration system. Glycol solutions should also be tested regularly; every 12 months for refrigeration duty and every 6 months for heating duty due to the enhanced corrosion risks present at elevated temperatures.
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