View air conditions on a psychrometric chart.
Psychrometric charts are charts adopted by ASHRAE that plot various thermodynamic properties of air-vapor mixtures. These charts are particularly useful in HVAC applications. The following properties describe what's called a state of air. Two properties are needed to fix the state of air, which means that two properties are needed in order to calculate every other property. The following 4 properties are plotted by Psychart by default:
Psychart also has the capability to derive the following state variables, which are optionally displayed using the Show Advanced State Variables switch in Display options.
This section will go over the options to configure Psychart.
Determines the size and padding of Psychart.
These options affect how the chart itself is displayed.
Allows the user to select whether measurements are being reported in US or SI units, the local altitude, graph bounds, flip X & Y, y-axis variable, and optionally display ASHRAE comfort regions (envelopes). For data center envelopes, these comfort regions follow the 2021 ASHRAE standard and are designed for data centers and IT spaces of various criticality. For human comfort envelopes, these comfort regions follow the ASHRAE-55 guidelines published in 2017. These human comfort envelopes are a function of metabolic rate (MET, which is dependent on the indoor activity), clothing level (CLO), and air speed. In both cases, the envelopes show the target region for conditioned air supplied into the indoor space.
In here we also define how data series are displayed using the series property.
These options help process the incoming data and change the visual appearance of data within the chart.
Psychart is capable of plotting several data series of states per panel. Due to the fact that 2 properties are needed to fix the state, at least two numeric time-dependent fields are required. In this set of options, we can define the legend, measurement types, series name (for internal use), show advanced state variables, change the point radius, optionally draw a line between adjacent points in time, and select a color gradient for the data series. Gradients always use the more saturated/contrasting colors for the more recent data points, regardless of which theme (light/dark) is preferred.
Different data series are independent from one another - one series may incorporate dry bulb and wet bulb measurements, and another may incorporate dry bulb and dew point measurements, for instance.
We can set styling options for Psychart manually, or use the default with Psychart.getDefaultStyleOptions(false/true) depending on whether dark theme is preferred.
If done manually, we can set the theme, font size and color, axis color, interval, and resolution, and default timespan.
Some errors can arise from the data options section due to the fact that wet bulb and dew point must be less than or equal to the dry bulb temperature and relative humidity must be within the range of 0-1. If relative humidity is a driving measurement, make sure that the measurement type is correct (0-1 or 0%-100%). For other measurements, make sure that they are correct, numerical values.
Psychart works best both visually and practically when observing a manageable amount of data, e.g. a short timespan of a few days at most. If Psychart is loading very slowly, try disabling a data series, or clearing the plotted data using Psychart.clearData() and start fresh. However, this will wipe all data from Psychart, so make sure it's saved somewhere!
View air conditions on a psychrometric chart