Cooling Load - People

The heat loads from a person depend on the activity level of the person. ASHRAE has tabulated heat loads both sensible and latent heat gains from people based on their activity levels, refer to ASHRAE Fundamentals. The loads from people can be calculated using these heat gain values, the number of people and the cooling load factor, as shown in the equations below. The cooling load factor takes into account the time lag factor and if it is not given it should be assumed to be 1.0.

Sensible loads

Heat Transfer Sensible Load from People for the Mechanical PE Exam

Latent loads

R-Value stands for thermal resistance and it is representative of a material’s ability to resist heat. This is opposite of the U-Factor and thermal conductance which are measures of a materials ability to conduct heat. The relationship between the R-Value, U-Factor and thermal conductance is shown in the following formula.

Heat Transfer Latent Load from People for the Mechanical PE Exam