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White Paper: Mechanical & Fluid Systems

Heat Pump and Flammable Refrigerant Application Solutions Using Explosion-Proof Relays

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The HVAC industry has been moving toward more sustainable refrigerants due to requirements in international treaties, which is something to celebrate. The newer, more flammable refrigerants pose some design challenges, including how to safely incorporate relays in these explosive environments. Relays that comply with explosion-proof standards can effectively support HVAC applications that rely on the newer refrigerants, including heat pumps, the adoption of which continues to grow in the United States and around the globe. In this white paper, learn more about the value and applications of explosion-proof relays.

Topics:
Green Design & Manufacturing Machinery Mechanical Components Mechanics
Overview

The white paper discusses the HVAC industry's transition to more sustainable refrigerants due to international treaties like the Montreal Protocol and the AIM Act of 2020, which mandate the reduction of high Global Warming Potential (GWP) gases. Traditional refrigerants such as R-22 and R-410A are being replaced by hydrofluoroolefins (HFOs), which have significantly lower GWP values and zero Ozone Depletion Potential (ODP). However, these newer refrigerants, classified as mildly flammable (A2L), introduce safety challenges, particularly concerning ignition sources in HVAC systems.

A key focus of the paper is the role of relays in HVAC applications, which can be potential ignition sources due to electrical arcing when contacts open or close. To address these risks, the paper emphasizes the importance of using explosion-proof relays that comply with safety standards such as IEC/EN 60079-1 and 60079-15. These relays are designed to operate safely in explosive gas environments, ensuring that they do not ignite flammable gases during operation.

The document highlights OMRON's advancements in explosion-proof relay technology, including the G5Q family of relays, which have been expanded to accommodate higher current loads while maintaining compact sizes. These relays are suitable for various HVAC applications, including heat pumps, compressors, and motors, and are designed to meet stringent safety standards.

Additionally, the paper discusses the Glow Wire Test (IEC/EN 60335-1), which ensures that components used in home appliances do not ignite or quickly self-extinguish when exposed to heat sources. The transition to electric heat pumps is also noted as a more environmentally friendly alternative to traditional gas-based heating systems, especially as electricity grids shift towards cleaner energy sources.

In summary, the white paper outlines the HVAC industry's shift towards safer, more sustainable refrigerants and the critical role of explosion-proof relays in ensuring safety and compliance in this evolving landscape.