The food industry, worth £96.1 billion to the UK economy, operates thanks in huge part to refrigeration technology that relies on the use of refrigerant gases. Even small leaks of these gases can have major environmental and financial implications.
Shaun Evers, managing director of Stonegate Instruments, gives the full story and explains why sophisticated new gas detection technology is to be welcomed.
Energy consumption in the refrigeration sector costs British industry approximately £300 million each year with the average site energy bill for a cold store totalling £0.5million.
According to the Institute of Refrigeration working with the Carbon Trust, a leak of just 1kg of refrigerant gases causes approximately the same environmental damage as driving a van 10,000 miles.
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They report that leaks of up to 30% of the charge during a year are not uncommon in commercial and industrial refrigeration.
The commercial refrigeration equipment market is driven by a number of factors including changing food consumption trends, rising international food trade and the growth of supermarkets and fast food chains.
Emerging markets in India and China are driving sales upwards and there are opportunities to be seized. Against this background, one of the industry’s key challenges is to develop more energy-efficient commercial refrigeration equipment and to respond to the global call to cut emissions of damaging greenhouse
Refrigeration in its infancy
The world’s first working vapour-compression refrigeration system – a closed-cycle that could operate continuously – was built in 1834. In 1859 a gas absorption refrigeration system using gaseous ammonia dissolved in water was developed by French inventor Ferdinand Carré.
From this point advancements continued rapidly with large commercial refrigerators soon in place, though these appliances were insecure and it was not uncommon for them to catch fire, explode or leak toxic gases.
In spite of this, the first commercially successful refrigeration shipping voyage was made in 1882 when a ship from New Zealand, fitted with a compression refrigeration unit for meat shipment, sailed to London, changing the future of the food industry.
Refrigeration became safer and available for domestic use thanks to the invention of synthetic refrigerants as chemical cooling agents in the 1930s but it wasn’t until 40 years later that these new substances were found to present a newly perceived environmental danger and a serious threat to the ozone layer.
Environmental cost
Man-made fluorinated gases (F-gases) can remain in the atmosphere for thousands of years and contribute to a global greenhouse effect. Equipment and appliances containing F-gases can have long lifetimes of up to 50 years.
F-gases account for just 2% of the European Union’s overall greenhouse gas emissions but they have risen by 60% since 1990 in contrast with all other greenhouse gases, which have been reduced.
As part of its policy to combat climate change, the EU passed legislation in 2006 to control F-gases and, in 2012, made a proposal to further cut emissions by two thirds of today’s levels by 2030.
The EU’s roadmap for moving to a competitive low-carbon economy in 2050 envisages a reduction of emissions of over 70% by 2030 for the industry sectors that use Fgases, which includes refrigeration.
Legislative regulations on ozone depleting chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), have been laid down with virgin HCFCs banned from 2010 and recycled or reclaimed fluids to be phased out by 2015.
Substances used as substitute refrigerants such as perfluorocarbons (FCs) and hydrofluorocarbons (HFCs) have now also come under criticism.
HFCs are among the most common F-gases which contain hydrogen, fluorine and carbon and are used in a multitude of applications including commercial refrigeration, industrial refrigeration and air-conditioning systems.
They were developed in the 1990s as a substitute for substances found to deplete the ozone layer. However, HFCs are powerful greenhouse gases with a global warming effect up to 23,000 times greater than CO2 and their emissions are growing fast. In 1997, FCs and HFCs were included in the Kyoto Protocol to the United Nations Framework Convention on Climate Change.
F-gas legislation
The refrigeration industry is one of five main industry sectors affected by EU F-gas legislation which aims to limit their release. Anyone manufacturing, supplying, using, installing or servicing equipment containing fluorinated greenhouse gases or ozone depleting substances must comply.
Under these regulations there is a legal obligation to test systems for leaks once a year if the charge is between 3 and 30kg and twice a year for systems with more than 30kg. Systems containing over 300kg of HFC must have permanent fixed leak detectors.
Leaks must be repaired and the system retested at the point of repair within one month. There is also a requirement to log refrigerant usage, leak tests and repairs. It is actually illegal to top up a system with refrigerant without first finding and repairing the leaks.
Refrigerant gas leaks are not only intrinsically hazardous to the environment, but to the pocket. If a gas leak occurs, a cold store’s energy consumption will increase to maintain the equipment’s cooling capacity.
It is estimated that £40 million per annum could be saved on energy costs in the cold storage industry if gas leaks were dealt with correctly.
Leaks are expensive in terms of downtime, service costs, refrigerant, electricity and CO2 emissions. This can be counteracted by applying best practice in leak testing, servicing, maintenance and repair.
Refrigerant Gas Leak Detection
No matter how good the manufacture, given time, vibration, temperature and environmental stress, tiny flaws in joint fittings, seams or welds are likely to become leaks.
These could be at the tail end of a weld fracture or a microgroove between fittings. Leaks larger than 0.5oz a year can be detrimental to the operation of any refrigeration system.
The most effective method of finding them is with an electronic detector able to identify a wide range of refrigerant gases including CFCs, HCFCs, HFCs and CO2.
Under European legislation, detectors must have a sensitivity of 5g/year and should be checked annually. For optimum reliability they should be checked after 25 hours’ use.
Increasingly sophisticated gas detection systems are now available which can accommodate a large number of remote refrigerant sensors using a compact central monitor unit which displays the status of each sensor with coloured LEDs.
These systems can accommodate logger functions that record one week of logs for all associated sensors – ideal, given EU legislation on reporting obligations. Gas detectors can offer both audible and visual alerts to warn personnel immediately should a gas leak occur.
With best of these systems able to provide a payback of less than two years, installing one is a wise investment for companies who are becoming progressively more aware of the impact that refrigerant gas leaks are having on the environment and of the financial cost of the resulting waste of energy.
New gas detection technology effectively addresses both the environmental issues surrounding the leak of gases and their commercial costs.
I agree! Ironically, the last thing on your mind happens to be the most important. The refrigerant is an often un-talked about component of your A/C system, but it contributes directly to its functionality. The refrigerant lines are what’s used to chill and condition the air in your home, and when there is a problem with them, you don’t get the cool air you want.