Building Science at UC Berkeley: Research

Automotive Interface for the UC Berkeley Multinode Model of Human Thermal Comfort

Charlie Huizenga, Research Specialist, CEDR 
Edward Arens, Department of Architecture & Director, CEDR
Zhang Hui, Associate Specialist, CEDR
Tom Duan, Graduate Student Researcher

Sponsor: Delphi Harrison Thermal Systems

The Center for Environmental Design Research at UC Berkeley has developed a multinode thermal comfort model that is capable of evaluating the impact of non-uniform thermal conditions on the human body.  The model is based Stolwijk's 25-node model of thermoregulation (Stolwijk and Hardy, 1977), which set out the fundamental concepts, algorithm, physical constants and physiological control subsystems for many contemporary comfort models.  The UC Berkeley model consists of 16 body segments, corresponding to our segmented thermal manikin (head, chest, back, pelvis, two shoulders, two arms, two hands, two thighs, two calves, and two feet), and five layers (clothing, skin, fat, muscle, and core tissues).

The model is capable of analyzing complex thermal asymmetries, gradients and transients and has been adapted for use in examining the impact of different thermal environments in an automobile on the thermal comfort of the occupants.  The model can calculate local (segment) skin temperatures, equivalent homogenous temperatures, and heat flux as well as whole body thermal sensation. Input to the model includes air temperature, surrounding surface temperatures, humidity, and air velocity for each of the 16 body segments as well as clothing and metabolic levels of the occupant.

The thermal environment experienced by an occupant in an automobile is often quite complex.  A significant component of this environment is the radiant temperature of the surfaces surrounding the occupant. Technologies such as advanced glazing can lower the solar load on a vehicle and reduce inside surface temperatures, providing improved thermal comfort for the occupants.  The impact of this technology on the comfort of the occupant can be quite significant, and our model will allow these impacts to be quantified.