As EVs gain popularity, concerns with range anxiety continue to surface among potential buyers, highlighting the fear that an EV may not have sufficient charge to reach its destination. In hopes of alleviating those fears, Hyundai Motor Group is developing an energy-efficient heating system for its EVs, referred to as the Radiant Heating System (RHS).
The RHS was first introduced in 2019, featuring customizable knee warmers in select Hyundai and Kia models. More recently, this technology was showcased in the Genesis Neolun Concept, which was unveiled last year. The primary objective of the RHS is to optimize energy usage, extending the vehicle’s range while improving overall driving comfort.
Genesis explained, teat transfer occurs through three main mechanisms: conduction, convection, and radiation. Conduction involves the transfer of heat through direct contact, commonly utilized in heated seats and armrests. Convection refers to the movement of heat through gases or liquids, such as warm air from car vents. Radiation, in contrast, is the emission of heat in the form of electromagnetic waves, similar to how the sun warms the Earth.
Hyundai Motor Group aims to integrate all three heat transfer methods in its vehicles. This includes conduction through heated seats and armrests, convection with positive temperature coefficient heaters, and radiation via radiant warmers.
The concept of radiant warmers was inspired by the Korean heating method known as “ondol,” which heats floors through conduction and subsequently warms the air by convection. Manju Oh, a Senior Researcher at the Group’s Integrated Thermal Management Research Lab, noted, “I was drawn to ondol as I was researching everyday examples of radiant heating.” The goal of applying ondol to EVs is to reduce energy consumption while enhancing passenger comfort.
The initial version of the RHS, which includes knee warmers, has received positive feedback. Sola Chung, another Senior Researcher, shared, “Conventional air conditioners usually take time to warm passengers. The RHS, however, directly transfers heat to the body, accomplishing the same task much more quickly.” The team is now advancing the RHS, with a test model that directs warmth to various body areas, utilizing a film-type heating element made from carbon nanotube material, which offers a larger heating surface compared to earlier models.
Preliminary trials of the next-generation RHS, powered by a new 48-volt power system, have shown reductions in energy consumption for heating and improvements in overall energy efficiency. The latest RHS design also addresses potential burn risks through hardware and software enhancements. The heating element’s thickness has been reduced to lower heat capacity, and a fabric with low thermal conductivity has been employed in areas of potential skin contact. Also, a capacitive touch sensor allows for immediate power shutdown when detecting contact with the body, while a safety system deactivates heating in case of component damage or software errors.
Researchers emphasize the RHS’s energy efficiency and user convenience. Sanghun Kim from the Group’s Thermal Energy Testing Team stated, “When traditional convection systems are used in conjunction with the RHS, energy consumption for heating can be reduced by as much as 17 percent.” Chung added that the system allows passengers to experience similar heating performance with less reliance on traditional heaters, which may improve humidity levels within the vehicle.
SangYup Lee, Head of Genesis Global Design, highlighted the unique experience offered by the Genesis Neolun Concept, stating, “What you feel in the Neolun with ondol is something you won’t feel in any other car.” The initiative aims to create a new experience that engages all five senses.