LivingPsychrometrics

This app offers four different calculations and shows the results both in a pane and on a psychrometric diagram: 1. Air treatment Calculates how to convert a given ambient air to a required design air. The steps involved are cooling with a given sensible heat factor, dehumidifying, heating and humidifying (adiabatic or steam). Depending on the given and required air conditions, some of these steps may not be needed.

2. Capacities Calculates the required capacity to cool down or heat up a given amount of air (e.g. air in your room).

3. Heat exchanger Calculates how warm room air heats up cool ambient air before supplying it as fresh air to the room. While heating up the ambient air, the heat exchanger cools down the room air, which may result in condensate. When the ambient air would be too cold, this calculation dimensions an electric heater to prevent condensate.

4. Carburetor icing Given a temperature and a dew point temperature, calculates the probability of icing in an airplane carburetor. Graphically shows the danger zones on a diagram.

These four calculations show the results in a pane, but also graphically in a diagram. You can choose between three different diagrams: 1. Psychrometric This is the classic diagram representing different kinds of air properties into a single diagram. You find detailed descriptions in standard books about air treatment, such as ASHRAE. This diagram shows lines of constant temperature, humidity ratio, relative humidity, enthalpy and specific volume.

2. Mollier This is probably the oldest diagram to represent air properties and named after its inventor Richard Mollier (1863-1935). To get a psychrometrics diagram from a Mollier diagram, swap it along the vertical axis and rotate it 90°. The Mollier diagram is heavily used in Eastern Europe and Germany and shows the same lines as in the psychrometrics diagram.

3. Dewpoint This diagram is meant for meteorologists and pilots. It is easy to read important weather data, such as temperature, dew point and relative humidity. However, this diagram shows the same constant lines as for the other two. Interestingly, the straight lines in the other two diagrams become curved lines in this one and vice versa.