1. Objectives Analyze processes in AHU and buildings

2. Single-Zone Systems Zone – any space with a thermostat

3. Air conditioning

4. Recirculation

5. Reheat

6. Evaporative Cooler

7. Air-to-air heat exchanger

11. Summary Show HVAC processes on a psychrometric chart Draw condition lines Define sensible heat ratio Draw HVAC processes for real buildings Single zone Multiple zone Skipping Chapter 9

12. HW2 Problem #9: An office building has: - Sensible load of 91000Btu/h - Latent load of 16000 BTU/h - Required amount of fresh air of 1000CFM - Supply air temperature is 55 F in winter and 93 F in winter. -Outdoor design parameters are : -Summer: DBT=105 F and RH=33% - Winter: 22 F and RH=80% -Surface temperature of the cooling coil in AHU is 45 F (when it operates). Calculate the energy for cooling and heating coils and steam humidifier for winter and summer design condition for CAV system that: a) control the relative humidity to 50% and room temperature to 74 F b) control only room temperature to 74 F Problems from the course book: 7.1, 7.21, 7.3, 7.4, 7.27, 8.5, 8.17, 8.20 Due: February 23 rd