These indices are more complicated than the Dry Resultant Temperature.
They combine the influence of air temperature, mean radiant temperature, air movement and humidity with that of clothing and activity level into one value.
The PMV index is a method of predicting if occupants will feel comfortable in a room.
Research was carried out in various locations to find out if people felt comfortable and this is used to determine levels of comfort.
The PMV index may be defined as the mean value of the votes of a large group of persons, exposed to the same environment with identical clothing and activity.
The predicted percentage dissatisfied (PPD) as a function of predicted mean vote (PMV).
The predicted percentage dissatisfied (PPD) can be obtained from the PMV using the following equation.
PPD = 100 – 95 exp [–(0.03353 PMV 4 + 0.2179 PMV2)]
The graph below shows typical comfort zones for winter and summer.
http://www.arca53.dsl.pipex.com/index_files/thermco3.htm
