Accession Number : ADA335481

Title :   The Effect of Perfusate Temperature in a Liquid Cooling System on Heat Strain and Heat Transfer

Descriptive Note : Final rept. 1955-1996

Corporate Author : NAVAL HEALTH RESEARCH CENTER SAN DIEGO CA

Personal Author(s) : Canine, M. K. ; Habib, C. M. ; Bernhard, R. ; Ashinger, A. ; Vurbeff, G. K.

PDF Url : ADA335481

Report Date : 28 SEP 1997

Pagination or Media Count : 28

Abstract : Decreasing perfusate temperature (Tp) in a liquid cooling system (LCS) leads to a proportional - increase in heat transfer (Q) when measured on a mannikin. However, it is uncertain if the linear relationship between Tp and Q holds when cooling is applied to humans. The purpose of this study was to determine the effectiveness of three different Tp to reduce heat strain in personnel required to walk on a treadmill (3 miles hr. 1 at 2% grade) for 60 min in a hot-humid environment (35 deg C and 65% relative humidity). Indices of heat strain and Q were measured in 12 subjects during one control condition (no cooling NC) and three experimental conditions with Tp of either 10 deg C (10C), 20 deg C (20C), or 30 deg C (30C). In this study, 10C and 20C significantly reduced heat stain when compared with 30C and NC. However; 10C did not significantly reduce heat strain further when compared with 20C. Although Q was significantly different among the cooling conditions, the difference between 30C and 20C was greater (i.e., 500 - 267 = 233 W) than the difference between 20C and 10C (i.e., 622 - 500 = 122 W). The smaller than expected Q for 10C may be attributed to cutaneous vasoconstriction potentiated by overcooling.

Descriptors :   *HEAT TRANSFER, *LIQUID COOLING, MILITARY PERSONNEL, TISSUES(BIOLOGY), HUMANS, COOLING, REDUCTION, LINEARITY, PROTECTIVE CLOTHING, ORGANS(ANATOMY), VASOCONSTRICTING, SKIN DISEASES, DISCOLORATION.

Subject Categories : Medicine and Medical Research
      Air Condition, Heating, Lighting & Ventilating
      Protective Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE