Current state-of-the-art thermoregulatory models do not simulate body temperature responses with the accuracies that are required for the development of automatic cooling control in liquid cooling garment (LCG) systems. Automatic cooling control would be beneficial in a variety of space, aviation, military, and industrial environments. It would optimize cooling efficiency, aid in making LCGs as portable and practical as possible, alleviate the individual from manual cooling control, and improve thermal comfort and cognitive performance. In this study, we implement an available state-of-the-art thermoregulatory model in a LCG environment and compare the thermal model response with experimental data for a 700 W rectangular type metabolic rate schedule. We modify the blood flow dynamics of the thermoregulatory model and identify a new vasoconstriction signal, i.e., the rate of change of hypothalamus temperature weighted by the hypothalamus error signal, which governs the thermoregulatory response during conditions of simultaneously increasing core and decreasing skin temperatures. With this new vasoconstriction dependency, the thermoregulatory model simulates rectal and mean skin temperature responses with root mean square deviations of 0.10°C and 0.48°C, respectively, which results in 40% and 17% reductions in the mean and peak body heat storage errors, respectively. Although the new model’s mean body heat storage error is within the allowable by an 11% margin, the peak body heat storage error exceeds the allowable by 222%, indicating that further refinements are needed. With additional improvements to the set-point temperatures, the central blood pool formulation, and the LCG boundary condition, it seems possible to achieve the strict accuracy that is needed for the development of automatic cooling control in LCG systems.

1.
Webb
,
P.
,
Troutman
,
S. J.
, and
Annis
,
J. F.
, 1970, “
Automatic Cooling in Water Cooled Space Suits
,”
Aerosp. Med.
0001-9402,
41
(
3
), pp.
269
277
.
2.
Fanger
,
P. O.
, 1970,
Thermal Comfort: Analysis and Applications in Environmental Engineering
,
Danish Technical Press
,
Copenhagen
.
3.
Flouris
,
A. D.
, and
Cheung
,
S. S.
, 2006, “
Design and Control Optimization of Microclimate Liquid Cooling Systems Underneath Protective Clothing
,”
Ann. Biomed. Eng.
0090-6964,
34
(
3
), pp.
359
372
.
4.
Smith
,
L. F.
,
Nair
,
S. S.
,
Miles
,
J. B.
, and
Webbon
,
B. W.
, 1993, “
Evaluating Human Thermal Models for Advanced Portable Life Support System Control Development
,”
Transactions of the Society of Automotive Engineers Journal of Aerospace
,
102
, pp.
1193
1203
.
5.
Tikuisis
,
P.
, 2000, “
Functional Modeling in Human Thermoregulation to Thermal Stress
,”
Proceedings of the Ninth International Conference on Environmental Ergonomics
, Dortmund, Germany.
6.
Werner
,
J.
, 1989, “
Thermoregulatory Models: Recent Research, Current Applications and Future Development
,”
Scand. J. Work Environ. Health
0355-3140,
15
, pp.
34
46
.
7.
Salloum
,
M.
,
Ghaddar
,
N.
, and
Ghali
,
K.
, 2007, “
A New Transient Bioheat Model of the Human Body and Its Integration to Clothing Models
,”
Int. J. Therm. Sci.
1290-0729,
46
(
4
), pp.
371
384
.
8.
Huizenga
,
C.
,
Hui
,
Z.
, and
Arens
,
E.
, 2001, “
A Model of Human Physiology and Comfort for Assessing Complex Thermal Environments
,”
Build. Environ.
0360-1323,
36
(
6
), pp.
691
699
.
9.
Wolf
,
M. B.
, and
Garner
,
R. P.
, 1997, “
Simulation of Human Thermoregulation During Water Immersion: Application to an Aircraft Cabin Water-Spray System
,”
Ann. Biomed. Eng.
0090-6964,
25
(
4
), pp.
620
634
.
10.
Tikuisis
,
P.
,
Gonzalez
,
R. R.
, and
Pandolf
,
K. B.
, 1988, “
Thermoregulatory Model for Immersion of Humans in Cold Water
,”
J. Appl. Physiol.
8750-7587,
64
(
2
), pp.
719
727
.
11.
Stolwijk
,
J. A. J.
, and
Hardy
,
J. D.
, 1977 “
Control of Body Temperature
,”
Handbook of Physiology—Reactions to Environmental Agents
,
D. H. K.
Lee
, ed.,
American Physiological Society
,
Bethesda, MD
, pp.
45
68
.
12.
Montgomery
,
L. D.
, 1974, “
A Model of Heat Transfer in Immersed Man
,”
Ann. Biomed. Eng.
0090-6964,
2
(
1
), pp.
19
46
.
13.
Gagge
,
A. P.
, 1973, “
A Two Node Model of Human Temperature Regulation in FORTRAN
,”
NASA
Report No. SP-3006.
14.
Fiala
,
D.
,
Lomas
,
K. J.
, and
Stohrer
,
M.
, 2001, “
Computer Prediction of Human Thermoregulatory and Temperature Responses to a Wide Range of Environmental Conditions
,”
Int. J. Biometeorol
0020-1728,
45
, pp.
143
159
.
15.
Fiala
,
D.
,
Lomas
,
K. J.
, and
Stohrer
,
M.
, 1999, “
A Computer Model of Human Thermoregulation for a Wide Range of Environmental Conditions: The Passive System
,”
J. Appl. Physiol.
8750-7587,
87
, pp.
1957
1972
.
16.
Werner
,
J.
, and
Webb
,
P.
, 1993, “
A Six-Cylindrical Model of Human Thermoregulation for General Use on Personal Computers
,”
Ann. Physiol. Anthropol.
0287-8429,
12
(
3
), pp.
123
134
.
17.
Wissler
,
E. H.
, 1985, “
Mathematical Simulation of Human Thermal Behavior Using Whole Body Models
,”
Heat Transfer in Medicine and Biology
,
A.
Shitzer
and
R. C.
Eberhart
, eds.,
Plenum
,
New York
, pp.
325
373
.
18.
Gordon
,
R. G.
,
Roemer
,
R. B.
, and
Horvath
,
S. M.
, 1976, “
A Mathematical Model of the Human Temperature Regulatory System—Transient Cold Exposure Response
,”
IEEE Trans. Biomed. Eng.
0018-9294,
BME-23
(
6
), pp.
434
444
.
19.
Qi
,
Y.
, 1994, “
A New Two-Dimensional Human Thermal Model and Study of Heat Transfer in Living Tissue
,” Ph.D. thesis, University of Texas, Austin, TX.
20.
Mungcharoen
,
T.
, and
Wissler
,
E. H.
, 1989, “
A New Two-Dimensional Human Thermal Model
,”
AIChE Symposium Series
, Philadelphia, PA.
21.
Kuznetz
,
L. H.
, 1979, “
A Two-Dimensional Transient Mathematical Model of Human Thermoregulation
,”
Am. J. Physiol.
0002-9513,
237
(
5
), pp.
R266
R277
.
22.
Smith
,
C. E.
, 1991, “
A Transient Three-Dimensional Model of the Human Thermal System
,” Ph.D. thesis, Kansas State University, Manhattan, KS.
23.
Werner
,
J.
, and
Buse
,
M.
, 1988, “
Three-Dimensional Simulation of Cold and Warm Defense in Man
,”
Environmental Ergonomics
,
I. B.
Mekjavic
,
E. W.
Banister
, and
J. B.
Morrison
, eds.,
Taylor & Francis
,
New York
, pp.
286
296
.
24.
Smith
,
L. F.
,
French
,
J. D.
,
Nair
,
S. S.
,
Miles
,
J. B.
, and
Webbon
,
B. W.
, 1996, “
Evaluation of Human Thermal Models for EVA Applications
,”
Transactions of the Society of Automotive Engineers J. Commercial Veh.
,
105
(
1
), pp.
698
706
.
25.
French
,
J. D.
,
Viswanath
,
A. D.
,
Nair
,
S. S.
,
Miles
,
J. B.
, and
Lin
,
C.
, 1997, “
Parameter Values and Assumptions in Human Thermal Modeling For EVA Applications
,”
Transactions of the Society of Automotive Engineers Journal of Aerospace
,
106
(
1
), pp.
579
586
.
26.
Stolwijk
,
J. A. J.
, 1970, “
Mathematical Model of Thermoregulation
,”
Physiological and Behavioral Temperature Regulation
,
J. D.
Hardy
,
A. P.
Gagge
, and
J. A. J.
Stolwijk
, eds.,
Charles C. Thomas
,
Springfield, IL
, pp.
703
721
.
27.
Pennes
,
H. H.
, 1948, “
Analysis of Tissue and Arterial Blood Temperatures in the Resting Human Forearm
,”
J. Appl. Physiol.
8750-7587,
1
, pp.
93
121
.
28.
Fiala
,
D.
, 1998, “
Dynamic Simulation of Human Heat Transfer and Thermal Comfort
,” Ph.D. thesis, De Montfort University, Leicester, UK.
29.
Schuh
,
H.
, 1957, “
Differenzenverfahren zum berechnen von temperatur-ausgleichsvorgängen bei eindimensionaler wärmeströmung in einfachen und zusammengesetzten körpern
,”
Forschung auf dem Gebiete des Ingenieurwesens
, Vol.
23
,
VDI-Verlag
,
Düsseldorf, Germany
, pp.
1
37
.
30.
Westin
,
J. K.
, 2008, “
An Improved Thermoregulatory Model for Cooling Garment Applications With Transient Metabolic Rates
,” Ph.D. thesis, University of Central Florida, Orlando, FL.
31.
Westin
,
J. K.
,
Kapat
,
J. S.
, and
Chow
,
L. C.
, 2008, “
Evaluating a Thermoregulatory Model for Cooling Garment Applications With Transient Metabolic Rates
,”
Proceedings of the ASME Summer Heat Transfer Conference
, Jacksonville, FL.
32.
Jones
,
A. M.
, and
Poole
,
D. C.
, 2005,
Oxygen Uptake Kinetics in Sport, Exercise and Medicine
,
Routledge
,
London
, p.
405
.
33.
Tikuisis
,
P.
,
Gonzalez
,
R. R.
, and
Pandolf
,
K. B.
, 1988, “
Prediction of Human Thermoregulatory Responses and Endurance Time in Water at 20 and 24°C
,”
Aviat., Space Environ. Med.
0095-6562,
59
, pp.
742
748
.
34.
Eberhart
,
R. C.
, 1985, “
Thermal Models of Single Organs
,”
Heat Transfer in Medicine and Biology—Analysis and Applications
,
A.
Shitzer
and
R. C.
Eberhart
, eds.,
Plenum
,
New York
, pp.
279
284
.
35.
Durkee
,
J. W.
, Jr.
, and
Antich
,
P. P.
, 1991, “
Characterization of Bioheat Transport Using an Exact Solution to the Cylindrical Geometry, Multi-Region, Time-Dependent Bioheat Equation
,”
Phys. Med. Biol.
0031-9155,
36
(
10
), pp.
1377
1405
.
36.
Durkee
,
J. W.
, Jr.
,
Antich
,
P. P.
, and
Lee
,
C. E.
, 1990, “
Exact Solutions to the Multiregion Time-Dependent Bioheat Equation I: Solution Development
,”
Phys. Med. Biol.
0031-9155,
35
(
7
), pp.
847
867
.
37.
Durkee
,
J. W.
, Jr.
,
Antich
,
P. P.
, and
Lee
,
C. E.
, 1990, “
Exact Solutions to the Multiregion Time-Dependent Bioheat Equation II: Numerical Evaluation of the Solution
,”
Phys. Med. Biol.
0031-9155,
35
(
7
), pp.
869
889
.
38.
Webb
,
P.
, and
Annis
,
J. F.
, 1967, “
Bio-Thermal Responses to Varied Work Programs in Men Kept Thermally Neutral by Water Cooled Clothing
,”
NASA
Report No. CR-739.
39.
Pisacane
,
V. L.
,
Kuznetz
,
L. H.
,
Logan
,
J. S.
,
Clark
,
J. B.
, and
Wissler
,
E. H.
, 2007, “
Thermoregulatory Models of Space Shuttle and Space Station Activities
,”
Aviat., Space Environ. Med.
0095-6562,
78
(
4
), pp.
A48
A55
.
40.
Kuznetz
,
L. H.
, 1975, “
Control of Thermal Balance by a Liquid Circulating Garment Based on a Mathematical Representation of the Human Thermoregulatory System
,” Ph.D. thesis, University of California, Berkeley, Berkeley, CA.
41.
Ganong
,
W. F.
, 2005,
Review of Medical Physiology
,
McGraw-Hill Medical
,
New York
.
42.
Xu
,
X.
,
Berglund
,
L. G.
,
Cheuvront
,
S. N.
,
Endrusick
,
T. L.
, and
Kolka
,
M. A.
, 2004, “
Model of Human Thermoregulation for Intermittent Regional Cooling
,”
Aviat., Space Environ. Med.
0095-6562,
75
(
12
), pp.
1065
1069
.
43.
Nyberg
,
K. L.
,
Diller
,
K. R.
, and
Wissler
,
E. H.
, 1997, “
Modeling of Human Thermal Regulation for Liquid Cooling Garment Applications
,”
ASME HTD
, Dallas, TX, Vol.
355
, pp.
119
126
.
44.
Wissler
,
E. H.
, 1986, “
Simulation of Fluid-Cooled or Heated Garments That Allow Man to Function in Hostile Environments
,”
Chem. Eng. Sci.
0009-2509,
41
(
6
), pp.
1689
1698
.
45.
Manier
,
L.
,
Johnson
,
T.
,
Nair
,
S. S.
, and
Miles
,
J. B.
, 2001, “
A Review of Muscular Efficiency Studies for Different Exercises
,”
31st International Conference on Environmental Systems
, Orlando, FL.
46.
Wissler
,
E. H.
, 1988, “
A Review of Human Thermal Models
,”
Environmental Ergonomics
,
I. B.
Mekjavic
,
E. W.
Banister
, and
J. B.
Morrison
, eds.,
Taylor & Francis
,
New York
, pp.
267
285
.
This content is only available via PDF.
You do not currently have access to this content.