MACS Monthly Newsletter - 2021 - JAN1

Total Vehicle Climate and Thermal ManagementTM

January 2021

By Dr. Mark Quarto, MACS Technical Contributor

Electric Vehicle Cabin Heating Systems
It's All About Systems Integration

Along Comes the Electric Vehicle

Since the Battery Electric Vehicle (BEV) does not contain an
engine to create heat for the passenger cabin, ancillary systems
must be included that will generate heat for the passenger compartment. The modern day BEVs began its entry back in the
mid-1990's with vehicles such as the Ford Ranger, GM EV1 &
S-10, and others. These vehicles had rudimentary heating systems that were " just adequate enough " to heat the passenger
cabin. Fast forward to present day BEVs and heating is no longer
a primary issue of concern, and it could be considered a much
simpler system found in traditional ICE vehicles. An example
for a BEV system (Chevrolet Bolt) utilizes a high voltage (HV)
electric heater, 12V pump to circulate the coolant, heater core,
heater hoses, coolant reservoir, and blower motor (not shown).
See Figures 2, 3.

clearmechanic.com

For centuries, there have been few changes to automotive
cabin heating systems with Internal Combustion Engines (ICE).
The traditional systems contained a heat exchanger (radiator),
coolant pump, heater core, heater hoses, coolant reservoir, and a
12V blower motor. By simply providing a drive belt to rotate the
coolant pump, it is a simple method of transferring heat from
the engine to the heater core to acquire heat for the passenger
cabin. See Figure 1.
This cabin heating system utilized waste heat from the engine that, heated liquid coolant (glycol and water) and routed
through the system to the heater core to heat the passenger
cabin. A very simple system that has worked effectively, so why
change it?

Figure 1: Graphic showing a traditional vehicle heating system, which utilizes a radiator, cooling fan and a heater core to
transfer heat to the cabin.
MACS Service Reports is the official technical publication of the Mobile Air Conditioning Society Worldwide, Inc., P.O. Box 88, Lansdale, PA 19446. The material published in MACS Service Reports expresses the views of the contributors
and not necessarily that of MACS. Every attempt has been made to ensure

January 2021

the accuracy of the content of MACS Service Reports. MACS, however, will
not be responsible for the accuracy of the information published nor will MACS
Worldwide be liable in any way for injury, labor, parts or other expenses resulting
from the use of information appearing in MACS Service Reports.

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MACS Monthly Newsletter - 2021

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