ASHRAE Journal - June 2022 - 6

INDUSTRY NEWS
Using Manikins to Evaluate
Evaporative Cooling in Humans
According to research conducted at the International
Centre for Indoor Environment and Energy (ICIEE),
Technical University of Denmark in Denmark and
Shinshu University in Japan, a dry thermal manikin
with an add-on system is suitable for evaluating local
cooling induced by sweating in humans. Upgrading an
existing dry thermal manikin to a sweating manikin
makes it possible to evaluate the evaporative cooling
ability of the surrounding thermal environment and
clothing worn.
Researchers Satoru Nagasawa; Tomonori Sakoi, Ph.D.;
and Arsen Krikor Melikov, Ph.D., Fellow/Life Member
ASHRAE, recently reported results of their study in
" Add-On Local Sweating Simulation System for a Dry
Thermal Manikin " in ASHRAE's Science and Technology for
the Built Environment (STBE). Sakoi spoke with ASHRAE
Journal about the research.
Why is it important to explore this topic now?
Sweat evaporative cooling is an effective countermeasure
against heat stress posed by the surrounding hot
PHOTO 1 Back of the thermal manikin with hollow tubes attached.
environment and intensive work loads. 1 mL (0.03 oz.) of
sweat evaporation takes away around 2400 J (2.275 Btu)
of heat from the skin's surface. The evaporative cooling
ability of the human body is becoming important for
current global warming and heat island issues. Global
warming and heat island issues increase environmental
heat stress to the human body. Low evaporative cooling
ability causes wet friction on the skin and increases
thermal discomfort. To reduce this friction, it is desirable
to increase the evaporative cooling ability of the
surrounding environment, such as by elevating airflow
and clothing water diffusion characteristics and
dehumidification.
What exactly is a dry thermal manikin and what is it
used for?
A dry thermal manikin has a similar shape to a human
body and emits heat. It has functions to measure surface
temperature and heat emission. The surface temperature
is controlled to emulate human skin temperature
exposed to the evaluated condition. Then, the thermal
manikin is used to evaluate heat transfer from the
human body to the surrounding environment through
clothing.
How does the add-on local sweating simulation work?
By using the thermal manikin with the add-on local
sweating simulation system, we can detect how sweat
secretion changes in humidity within the microclimate
around the human body. Also, we can evaluate
the evaporative cooling ability of the surrounding
environment including humidity, airflow and clothing
effects.
The current system is developed to apply to the back
of the manikin. We succeeded to diffuse water over the
back area (8.8% of whole-body area) without the assistance
of gravity (the validation was done using a sleeping
thermal manikin) using only six water supply tubes that
had a water repellent hollow tube at the end.
The system can be applied to other body segments.
However, the remaining technical issue to be solved in
6
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ASHRAE Journal - June 2022

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