Discussion on the Thermal Comfort
Calculator What do
the terms mean? (For
a detailed overview on comfort
click
here)
Predicted Mean Vote(PMV) is a scale used by your interior
environmental design professional (Environmental
Ergonomists) to predict comfort. Ideal
range is between -0.5 and +0.5 (Neutral).
Percentage of People Dissatisfied (PPD): If 85% of the occupants are
satisfied (or 15% dissatisfied) with their interior environments,
then the Building/HVAC
system is generally considered acceptable. Some things like floor surface temperature, and stratification can influence comfort more than other metrics. Statistically over 50% of
home owners are dissatisfied for one reason or another – but you can
see why by using the comfort calculator.
Air Temperature is what an ordinary thermometer would measure.
Did you notice what happened when you raised or lowered the
air temperature. Temperature stratification also plays a
role in local discomfort.
Radiant Temperature:
At rest the human body exchanges between 50% and 60% of its
sensible heat via radiation. Notice the sensitivity of
radiant on comfort. Also note the temperature you are controlling is not the surface temperature of a radiant floor for example but the Mean Radiant Temperature of the space.
Learn more about radiant systems.
Relative Humidity is how dry or clammy you would feel. Think
what happens to air after you have had a shower or if the air has been dehumidified by an air conditioner. (Learn More)
Air Velocity is how fast the air is moving through the room.
Air can move naturally through convection or is forced by fans. What
is the relationship
between air temperature and air velocity - play with the
indicators and find out. (Learn More)
Activity Rate describes what you are doing ...afternoon nap,
or playing tennis perhaps? (Learn More)
Clothing Level describes what you might be wearing while doing an activity.
Be sure to check out
our new student
design validation software tools for radiant cooling
and heating systems. |
