Objectives

• Analyze processes in AHU and buildings

Single-Zone Systems

• Zone – any space with a thermostat

Air conditioning

Recirculation

Reheat

Evaporative Cooler

Air-to-air heat exchanger

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

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 Fb) 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 23rd