Components for Heating, Ventilation, and Air Conditioning
The components of heating, ventilation, and air conditioning technology (HVAC for short) map the conditioning of the room air in terms of temperature and water content (ratio of the masses of water vapor and dry air).
Central variables in air conditioning technology are
Temperature, Pressure, Norm Conditions
The Ambient temperature in the Input data of the Fresh_Air component is linked to the Weather data in the project master data by default.
The standard conditions for calculating the standard volume flow of air are the temperature of 273.15 K = 0 °C and the pressure of 1.01325 bar in accordance with DIN 1343.
Humidity
TOP-Energy calculates with the mass Mixing ratio. Alternatively, you can also specify the Relative humidity, which, unlike the mixing ratio, is always linked to a specific air temperature.
The Mixing ratio (also called absolute humidity) indicates in g/kg the mass of gaseous water vapor (i.e., not liquid water, such as raindrops and fog droplets, or solid water in the form of ice and snow) per mass of dry air.
In contrast, the Water vapor content (= specific humidity), which is contained in the project’s Weather data, is the mass of gaseous water vapor per mass of humid air.
Relative humidity, which is also included in the project’s Weather data, indicates the ratio of the current water content to the maximum possible water content for the current temperature and pressure in %.
Specify the maximum minimal acceptable Mixing ratio [g/kg] (or the minimum Relative humidity [%] in relation to a specific Air temperature [‘degC]) in a Humidifier component.
State Changes
Changes in state are necessary to condition the air in terms of temperature and water vapor content. For dehumidification, the temperature is lowered until 100 % humidity is reached so that the condensed water can be removed from the air. The following diagram illustrates the processes of cooling and dehumidification (blue) and heating and humidification (orange) in simplified form. During dehumidification, the temperature is lowered until the desired water content is achieved, then the desired temperature is set by heating. To increase the water content, on the other hand, the temperature must first be raised and then water vapor added to the air using the humidifier.
Integration Into a Scheme
The sequence of state changes must be observed when arranging the components.
A Heating Battery must follow the cooling components.
The Humidifier must follow the Heating Battery.
The following components are available in two variants: electricity-operated (material model MM_Electricity) and heating/cooling-operated (material model MM_Water):
Heat recovery is mapped with the Heat Transfer components for Air.
Optimization
Optimization ensures that the individual components are only used during periods in which they are required to maintain the specified conditions (temperature, mixing ratio). There may be times when cooling, dehumidification, heating, or humidification do not take place. Heat recovery may only be of seasonal importance.
