452 What effects are taken in account by a the mean radiant

4.52 What effects are taken in account by (a) the mean radiant temperature, (b) the operative temperature, and (c) the adiabatic equivalent temperature? (3)

Solution

1- The mean radiant temperature (MRT) is defined as the uniform temperature of an imaginary enclosure in which the radiant heat transfer from the human body is equal to the radiant heat transfer in the actual non-uniform enclosure. MRT is a concept arising from the fact that the net exchange of radiant energy between two objects is approximately proportional to their temperature difference multiplied by their ability to emit and absorb heat (emissivity). It is simply the area weighted mean temperature of all the objects surrounding the body.

2-Operative temperature also known as Dry resultant temperature, or Resultant temperature, is defined as a uniform temperature of a imaginary black enclosure in which an occupant would exchange the same amount of heat by radiation plus convection as in the actual nonuniform environment.

3- Adiabatic equivalent temperature (also known as pseudoequivalent temperature): The temperature that an air parcel would have after undergoing the following process: dry-adiabaticexpansion until saturated; pseudoadiabatic expansion until all moisture is precipitated out; dry- adiabatic compression to the initial pressure.