Wellbeing in buildings


Heat pump growth drives demand for ATEX relay designs


As the world takes steps to safeguard the planet from atmospheric calamity, new hazards demand tighter regulations in heating and refrigeration. Measurement and control devices face new applications and regulations, according to Samira Amani, Strategic Marketing Manager Automation, Omron Electronic Components Europe B.V.


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he world is beginning to phase out its use of gas boilers in favour of heat pumps. This brings-in new challenges with the need to identify solutions that mitigate the impact of global warming. whilst ensuring safety of heating and cooling plant. Further, our need to reduce reliance of fossil fuels is highlighted by recent volatility of global gas prices. In Europe, the REPowerEU Plan has the further aim of phasing-out our dependency on Russian fossil fuels. Reducing the carbon footprint will protect consumers as well as the atmosphere. These goals are underpinned by three pledges: to accelerate the transition to clean energy, diversify energy resources and reduce consumption overall. To achieve these goals, gas boilers are going to be limited by EU Community policy Repower Plan, with further investments expected on solar and renewable energies. In particular, the European Union should aim at doubling the current deployment rate of individual heat pumps, resulting in a cumulative 10 million units over the next five years. Extending these ambitions, REPowerEU ramps-up the schedule to a target of 20 million heat pumps installed by 2026 and close to 60 million by 2030.


Europe together


To meet these targets, the German government declared a new heating strategy focusing on district solutions with a mandate to make heat pumps mandatory as of January 2025. The deepening fossil fuel crisis and Russia’s war in Ukraine has – at the time of writing – been brought forward to make heat pumps the mandatory standard by January 2024. The Netherlands pledges similar action. In 2018,


fossil fuels were meeting 21 per cent of Dutch residential heating demand, compounded by the country’s liberal use of greenhouses in agriculture. The country wants hybrid heat pumps to become standard


26 January 2023


when existing boilers are replaced. Heat pumps will become mandatory from 2026. Meanwhile, Britain has declared to target 600,000 heat pumps annually by 2028 and will be banning the installation of gas boilers in new-build properties from 2025. The UK’s “10 Point Plan for the Green Industrial Revolution” has a longer-term vision of delivering 19 million heat pumps. This will help to reduce carbon emissions and reach net carbon zero by 2050. France has pledged to end government subsidies


for the installation of new residential gas heaters and boost support for renewable energy heating, whilst Italy’s government has also declared their intention to prohibit residential gas heaters from 2029. Achieving these targets brings in new challenges with the need to find solutions that mitigate the impact of global warming whilst ensuring safety of heating and cooling plant.


Taming refrigerants


It is well-known that older refrigerants compromise the atmosphere. CFCs are notorious as destroyers of the ozone layer, and subsequent alternatives still have the potential to accelerate global warming – not to mention the damaging effects on humans and the ecosphere. Low-carbon systems are an obvious solution, giving


way to new, environmentally friendly, refrigerants. The issue is: that refrigerants with low ozone depletion potential (ODP) and the lowest Global Warming Potential (GWP) brings hazards of its own. A refrigerant is a working fluid used in the


refrigeration cycle of air conditioning systems and heat pumps, where in most cases they undergo a repeated phase transition from a liquid to a gas and back again. Refrigerants are regulated due to their toxicity, flammability, and the contribution of CFC and HCFC refrigerants to ozone depletion and that of HFC refrigerants to climate change. To utilise low GWP, flammable gas explosion-proof design will need to be phased-in for all forms of heat pumps and refrigeration.


Standards for safety


The American Society of Heating, Refrigerating and Air-conditioning Engineering standard (ASHRAE) classifies refrigerants by hazard based on toxicity and flammability. Common non-polluting refrigerants such as R290 (propane), R1270 (propene) and R600a (isobutane) present zero ODP and low GWP ratings. However, they are rated to A3 standard, i.e., highly flammable. This means that utilising low GWP (Flammable) Gas Explosion proof design is mandatory


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for heat pumps and refrigeration. These considerations are even more applicable in the case of extremely flammable hydrogen boilers. A potentially explosive atmosphere exists when a


mixture of air gases, vapours, mists, or dusts combine in a way that can ignite under certain conditions. Across Europe the equipment and protective systems intended for use in potentially explosive atmospheres (ATEX) cover a range of products, including those used on fixed offshore platforms, petrochemical plants, mines, and flour mills, amongst others. Explosion-proof relays, switches and similar


devices come under the regulations of IEC60335-2-40 “Particular requirements for electrical heat pumps”. With air conditioners and dehumidifiers, the IEC 60730 / UL508 regulations expand applications for flammable refrigerants such as R290. When it comes to real life usage, specific regulations


apply to varying types of applications, from transport refrigerators, through chillers and air conditioning, to heat pumps and hydrogen boilers. This in turn, makes it necessary to develop fresh solutions that deliver protection whilst addressing market needs.


Relays go explosion-proof


Amongst the early gains are the certifications of sealed and open relays that have already gained approval to VDE IEC60079-15. Omron’s sealed PCB relay G9B, for example,


provides safe, high capacity switching with compact size. Already used in applications such as refrigerators, air conditioners, home appliances and small electric appliances, the switch is qualified for use in proximity with high-risk refrigerants. Under development, the G6RN relay family will introduce an unsealed model –EL1 and its sealed counterpart –EL2. Both carry approval to IEC60079-15 standards. Going forward, additional versions will have approval to IEC60079-15 with specific VDE and UL approvals for motor loads, including compressors for refrigeration.


IP67 sealed switches are safe, whatever the refrigerant


New versions of switches sealed to IP67 will also prove ideal for safe operation in proximity with highly flammable refrigerants. Models with sliding contact construction feature a long stroke and provide high reliability along with high insulation performance.


MEMS sensors keep fluids flowing


Monitoring air and liquid flow ensures the correct and optimal operation of heat pumps, refrigeration plant and air conditioning systems, enhancing combustion efficiency in boilers, and supplying feedback control of air conditioning by measuring the amount of air and amount of ventilation. MEMS flow sensors offer a safe measurement solution for flow rate, velocity, and differential pressure of hazardous refrigerants. High accuracy and wide range ability of flow rate sensors supports the diverse needs of flow measurements. Velocity-type sensors save energy with airflow sensing, whilst optimising air conditioning control without sacrificing quality.


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