IMPORTANT - This version of the tool (v2.0.0) complies with the ASHRAE 55 2017 Standard. This version is no longer
supported and may contain errors that have been fixed in newer releases.
Please visit the
CHANGELOG
page to find out more.
NOTE: In this psychrometric chart the
abscissa is the dry-bulb temperature, and the mean radiant temperature (MRT) is fixed,
controlled by
the inputbox. Each point on the chart has the same MRT,
which defines the comfort zone boundary. In this way you can see how changes in MRT affect
thermal
comfort. You can also still use the operative temperature
button, yet each point will have the same MRT.
NOTE: In this psychrometric chart the
abscissa is the operative temperature and for each point dry-bulb temperature equals mean
radiant
temperature (DBT = MRT). The comfort zone represents the
combination of conditions with the same DBT and MRT for which the PMV is between -0.5 and
+0.5,
according to the standard.
NOTE: This chart represents only two variables, dry-bulb temperature and relative
humidity.
The PMV calculations are still based on all the psychrometric
variables, but the visualization becomes easier to understand.
NOTE: Method is applicable only for buildings without mechanical cooling systems and
where there
is easy access to operable windows and occupants may freely
adapt their clothing to the indoor and/or outdoor thermal conditions. The criteria for the
spaces are
the following: (a) There is no mechanical cooling or heating
system in operation; (b) Metabolic rates ranging from 1.0 to 1.3 met; (c) Occupants are allowed
to
freely adapt their clothing insulation.