Basic of HVAC Design
HVAC: HVAC means Heating Ventilation and Air-Conditioning. The design and implementation of a Heating, Ventilation, and Air-Conditioning (HVAC) system is to help maintain good indoor air quality through adequate ventilation with filtration and provide thermal comfort. HVAC systems are among the largest energy consumers in any premise. The choice and design of the HVAC system makes the difference in any living and working environment.
There are four basic processes in an HVAC system which can perform on moist air:
Cooling- Lowering the air temperature. Heating- Raising the air temperature. Humidification- Raising the moisture content in the air (adding the moist air). Dehumidification- Lowering the moisture content in the air (removing the moist air).
Note that HVAC processes can also be a combination of the above four basic actions. These combinations include the following:
Heating and humidification- Increasing the temperature and moisture content of the air at the same time. Heating and dehumidification- Increasing the temperature and decreasing the moisture content of the air at the same time. Cooling and humidification- Decreasing the temperature and increasing the moisture content of the air at the same time. Cooling and dehumidification- Decreasing the temperature and moisture content of the air at the same time.
Enthalpy: Enthalpy is the sum of the internal energy or the total heat content of the ai r. In other words, warm and humid air can have the same heat content as hot and dry air. Enthalpy of dry air at 0% relative humidity. Enthalpy of saturated air or 100% relative humidity.
Air Density Elevation has an effect on psychrometric analyses. As elevation changes, so does the air density.