The Effect of Perfusate Temperature in a Liquid Cooling System on Heat Strain and Heat Transfer
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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 28, 1997
- Accession Number
- ADA335481
Entities
People
- A. Ashinger
- C. M. Habib
- G. K. Vurbeff
- M. K. Canine
- R. Bernhard
Organizations
- Naval Health Research Center