Chapter 6
Temperature, Heat flow and
Evaporation Measurement
Nguyen Viet Dung
Department of Electronic Technology and Biomedical Engineering, Hanoi University of Science and Tech.
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6.1. OBJECT QUANTITIES
6.2. TEMPERATURE SENSORS
6.3. NONCONTACT TEMPERATURE MEASUREMENTS
6.4. CLINICAL THERMOMETERS
6.5. HEAT FLOW MEASUREMENTS
6.6. EVAPORATION MEASUREMENTS
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6.1. OBJECT QUANTITIES
6.1.1. Units of Thermal Quantities
- Thermodynamic or absolute.temperature: K (kelvin) while Celsius
temperature: 0C (Celsius)
- Unit of heat in medical field: cal (calorie)
150C calorie (cal15): heat required to warm 1 g of water from 14.50C to
15.50C at pressure of 101.325 kPa
Heat flow rate (công suất nhiệt) W = J/s
Density of heat flow rate (mật độ công suất nhiệt): W/m2
Heat conductivity (độ dẫn nhiệt): W/m.K
Heat capacity (nhiệt dung): J/K
KC 19.273 0 0=
J 1855.4cal 1 15 =
J 1868.4cal 1 IT =
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- The content of water vapor in a gas can be expressed as:
+ Absolute humidity: water vapor concentration, g/m3
+ Water vapor pressure: kPa
+ Relative humidity:
-Dew point: temperature at which relative humidity becomes 100%
when the gas is cooled
- Evaporation rate of water vapor from the body: g/m2.h or mg/mm2.h
( )
%100xppRH (Sat) OHOH 22
=
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6.1.2. Requirements of Measurement Ranges
-In humans and homeothermic animals, the temperature of the central
part of the body is stabilized by a physiological thermoregulatory
function
-“Body temperature”: temperature of deep tissue at the body central
part, core temperature or deep body temperature
- Core temperature: 35 40 0C
Resolution of 0.1 0C is generally required
- Skin temperature: varies at least between ambient temperature and
core temperature
Measured in physiological studies, clinical diagnosis, and patient
monitoring