Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!

Discomfort Index

Comfort vs. dry bulb, wet bulb and dew point temperature.

The Discomfort Index can be expressed as

DI = 0.4 (t_d + t_w) + 15 (1)

or alternatively

DI = 0.55 t_d + 0.2 t_dp + 17.5 (1b)

where

DI = Discomfort Index

t_d = dry bulb temperature (^oF)

t_w = wet bulb temperature (^oF)

t_dp = dew point temperature (^oF)

The higher the value - the higher the value of discomfort.

Relative humidity in moist air can estimated by measuring the dry and wet bulb temperature.

Clo is used as a measure of clothes thermal insulation.

Dry Bulb, Wet Bulb and Dew Point temperatures can be used to determine the state of humid air.

Maximum work load vs. temperature and relative humidity.

Equivalent heat index vs. air temperature and relative humidity - in degrees Fahrenheit and Celsius.

Human work effort levels vs. energy expenditure and associated heart rates.

Recommended indoor comfort temperatures vs. outdoor temperatures.

Human metabolic heat gain in air conditioned rooms.

Dry and wet bulb temperature, specific volume, relative humidity, enthalpy and more.

Acceptable indoor air quality and required make up air.

PMV index predicts mean comfort response of a larger group of people.