This issue focuses on the outdoor air ventilation heating and cooling energy consumption data that is provided in the table and is used to create Fig 0108V. The data represents the energy required to heat and cool the outdoor air to maintain 55? F leaving a typical coil or heat exchanger. The sensible ventilation cooling energy consumption is calculated for every hour that the outside air temperature is above 55?. Latent cooling energy is calculated for every hour that the outside air humidity ratio (Woa) is above the humidity ratio associated with the desired setpoint of 55? at saturated conditions (Wsat). The sensible heating energy is calculated for every hour that the outside air temperature is below the desired setpoint of 55?. The following formulas are utilized to generate the data.
Sensible cooling ton-hrs?cfm= [p x Cpa x K x (toa-tsp)] ? 12,000
Latent cooling ton-hrs/cfm = [p x K x Hfg x (Woa-Wsat)] ? 12,000
Sensible heating therms/cfm = [p x Cpa x K x (tsp-toa)] / 100,000
K = Conversion factor (60 min/hr);
p = Air density (lbm/cf), adjusted for altitude;
Cpa = Specific heat of air (.24 Btuh/lbm-F);
Toa = Outside air drybulb (F);
Tsp = Drybulb supply air setpoint temperature (F);
Hfg = Heat of vaporization of water (1054.8 Btuh/lbm);
Woa = Outside air humidity ratio (lbw / lba);
Wsat = Humidity ratio (lbw/lba) coinciding with tsp saturated.