Effects of dry-bulb and humidity design setpoints on theoretical energy used in ventilation.

The purpose of this paper is to present the energy required to condition a constant volumetric airflow and determine the variability of this energy due to changes in the design dry bulb and humidity setpoints. Hourly weather data from a typical year from 32 European locations and long-term data from 11 American locations were analyzed to determine the coincident dry-bulb and dew-point temperatures. These data were then analyzed to determine the heating, cooling and moisture removal energy requirements for a constant mass of airflow per hour. It was found that significant amounts of energy were used to heat the air to the desired setpoint with smaller amounts being used for air-conditioning. In situations where air conditioning is used, a significant amount of this energy is used in dehumidifying the air. It was found that the energy used was highly sensitive to the heating, cooling and relative humidity setpoints. Empirical equation coefficients are presented for each location to predict the heating energy required as a function of the setpoint. The variation in energy requirements due to dry-bulb and humidity setpoints are also presented for those locations with significant air conditioning loads.