by: Edward de Ridder • 33
The Sercom KlimaCalc application is a climate calculator that can be used to calculate the composition of the air in a space when two properties are known.
The Sercom KlimaCalc application is based on the Mollier diagram. This is a graphic representation of the relationship between temperature, humidity and enthalpy (energy content of the air) and is basically a very useful aid for architects, designers and horticulture businesses who have to make climate and climate-control calculations.
- calculating the moisture content when heating air by a specific number of degrees Celsius.
- calculating the temperature at which condensation occurs.
- calculating the humidity deficit at a specific temperature (increase).
- converting a given temperature of humidity deficit to relative humidity and vice versa.
- calculating the final composition of the air after mixing air of 2 different compositions.
Explanation of KlimaCalc and climate properties
When 2 of the 7 climate properties listed below are known, the other climate conditions can be calculated!
Temperature [ °C ]
The temperature (dry bulb) of the environment’s air, measured with a thermometer, psychrometer or electronic meter.
Wet bulb temperature [ °C ]
The temperature of the air, measured with a psychrometer or dry/wet bulb meter. The wet bulb temperature is the lowest temperature achieved by air when so much water has evaporated that the air is saturated.
Dew point [ °C ]
The dew point is the temperature of the air at which condensation occurs.
Energy content [ kJ/kg ]
The energy content of the humid air is also known as the heat content or enthalpy, expressed in kJ/kg. This energy content of humid air can be considered a function of the temperature AND the moisture content of the air. An example of the energy content:
- air at 25.0°C with a high energy content feels clammy and sticky.
- air at 25.0°C with a low energy content feels dry and pleasant.
Relative humidity [ % ]
The relative humidity is the ratio between the prevailing vapour pressure (the actual quantity of moisture in the air, also called the absolute moisture content) and the maximal vapour pressure at the same temperature and air pressure. Vapour pressure is given in %. When the relative air humidity reaches 100%, the invisible water vapour in the air precipitates as drops on colder surfaces.
Mixing ratio [ g/kg ]
The mixing ratio is defined as the number of grams of water vapour found in a kilogram of dry air, or the prevailing vapour pressure. The maximum moisture content depends on the temperature and increases with rising temperature (warm air can hold more moisture than cold air).
Humidity deficit [ g/kg ]
The humidity deficit is the number of grams of moisture that can be added to 1 kilogram of air to bring it up to saturation (RH 100%). Saturated air therefore has a humidity deficit of 0 g/kg and cannot absorb any more water. The drier the air, the higher its humidity deficit.
Tags: sercom klimacalc , enthalpy of moist air calculator , klimacalc , sercom sygin