Industrial
Heat pumps present an explosive challenge for electronic designers
By Samira Amani, strategic marketing manager automation, Omron Electronic Components Europe H
eat pumps have great potential for reducing global warming, extracting heat from the air or the ground to warm commercial and domestic spaces cheaply and with minimal or no fossil fuel emissions. However, they rely on refrigerants which can themselves present environmental hazards. Unfortunately, refrigerants that have the lowest
environmental impact are also flammable. This brings new challenges for the system designer. Fortunately, relay and switch manufacturers like Omron are already offering solutions that are ATEX compliant, making them suitable for use in this environment.
The growth of heat pumps Europe is beginning to phase out its use of gas boilers in favour of heat pumps. Gas boilers are going to be limited by the EU Community Policy Repower Plan, and the European Union is aiming to double the current deployment rate of individual heat pumps, resulting in a cumulative ten million units over the next five years. Extending these ambitions, REPowerEU ramps-up the schedule to a target of twenty million heat pumps installed by 2026 and close to sixty million by 2030.
Following that, the German government has declared a new heating strategy focusing on district solutions with a mandate to make heat pumps mandatory as of January 2025. The Netherlands wants hybrid heat pumps to become standard when existing boilers are replaced and is making heat pumps mandatory from 2026. 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. 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.
If these targets are achieved, fossil fuel use will be greatly reduced, but each heat pump uses refrigerants in its design,
16 April 2023
greatly expanding their use. The issue is that refrigerants with low ozone depletion potential (ODP) and the lowest Global Warming Potential (GWP) bring hazards of their own. In fact, low GWP refrigerants are highly flammable and consequently gas explosion proof design is mandatory. ATEX-approved components could be a good solution to simplify the design and meet safety regulations for refrigeration, vending machines and heat pumps.
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
Components in Electronics
ODP and low GWP ratings. However, they are rated to A3 standard, i.e., highly flammable. This means that fresh solutions are required for the components used in the design of heat pumps, air conditioning and refrigeration systems. 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 operating 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. 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 to 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.
Sealed standard relays go explosion-proof
Amongst the early gains are the certifications of sealed and unsealed relays that have already gained approval to VDE IEC60079- 15. Here is one example. Omron’s G5NB is a miniature relay with 1-pole 5A/7A switching
www.cieonline.co.uk
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