IEQc6.2 Thermal Comfort, Design

The ASHRAE Thermal Comfort Tool v2 includes a Mean Radiant Temperature calculator. The software CD may be purchased directly from ASHRAE, and the cost is $117 ($99 for ASHRAE members). There are other tools available, but I'm not familiar with them or how they handle the MRT. The operative temperature is calculated as per Appendix C of ASHRAE Standard 55-2004. This calculation is dependant on the relative air speed, air temperature and mean radiant temperature and is pretty straightforward. In my opinion, the decision on what values to use for the MRT calculation is perhaps the most difficult step in thermal comfort analysis.