xv Chapter 29 Air Distribution .................................................... 718 29.1 Air Properties and Behavior ................... 719 29.2 Air Circulation ........................................ 721 29.3 Basic Ventilation Requirements ............. 722 29.4 Air Ducts ................................................ 726 29.5 Duct Sizing ............................................. 742 29.6 Fans ....................................................... 748 29.7 Air Curtains ............................................ 754 Chapter 30 Ventilation System Service .................................... 758 30.1 Airflow Measurement ............................. 759 30.2 Special Duct Problems and Duct Maintenance .......................................... 764 30.3 Fan Service............................................ 770 30.4 Filter Service .......................................... 770 Section 10 Air-Conditioning Systems Chapter 31 Self-Contained Air-Conditioning Systems ................ 776 31.1 Principles of Cooling and Humidity Control ................................................... 777 31.2 Room Air Conditioners .......................... 779 31.3 Packaged Terminal Air Conditioners (PTACs) ....................... 786 31.4 Console Air Conditioners ....................... 790 31.5 Portable Air Conditioners ....................... 792 Chapter 32 Residential Split Air-Conditioning Systems .............. 796 32.1 Split Air-Conditioning Systems .............. 797 32.2 Comfort Cooling Controls ...................... 799 32.3 Central Air-Conditioning Systems .......... 800 32.4 Installing Central Air Conditioning ......... 804 32.5 Servicing Central Air-Conditioning Systems ................................................. 811 32.6 Ductless Split Systems .......................... 816 Chapter 33 Commercial Air-Conditioning Systems .................... 830 33.1 Rooftop and Outdoor Units .................... 832 33.2 Variable Refrigerant Flow (VRF) Systems ................................................. 843 33.3 Chillers ................................................... 847 33.4 Cooling Towers ...................................... 858 Chapter 34 Absorption and Evaporative Cooling Systems ........... 872 34.1 Absorption Refrigeration Systems ......... 873 34.2 Absorption Cooling Systems ................. 876 34.3 Absorption System Service ................... 887 34.4 Evaporative Cooling ............................... 891 Chapter 35 Humidity Control ................................................. 898 35.1 Humidity Levels and Comfort ................ 899 35.2 Types of Humidifiers .............................. 902 35.3 Servicing and Installing Humidifiers ...... 907 35.4 Dehumidifying Equipment ...................... 908 Chapter 36 Thermostats ....................................................... 912 36.1 What Is a Thermostat? .......................... 913 36.2 Types of Thermostats ............................ 917 36.3 Line-Voltage Thermostats ...................... 923 36.4 Low-Voltage Thermostats ...................... 923 36.5 Millivolt Thermostats .............................. 926 36.6 Digital and Programmable Thermostats ........................................... 926 36.7 Thermostat Installation .......................... 931 36.8 Thermostat Diagnostics ......................... 935 36.9 Zoned Systems ...................................... 938 Chapter 37 Heating and Cooling Loads .................................... 952 37.1 Heat Transfer ......................................... 953 37.2 Heat Loads ............................................ 954 37.3 Calculating Heat Leakage ...................... 955 37.4 Other Factors Affecting Heat Loads ...... 970 37.5 Heating and Cooling Load— Manual J Method ................................... 976 Section 11 Heating Systems Chapter 38 Forced-Air Heating Fundamentals........................... 990 38.1 Basic Components ................................ 991 38.2 Furnace Types and Construction ........... 995 38.3 Forced-Air Duct Arrangements .............. 997 38.4 Makeup Air Units ................................... 997 38.5 Blower Controls ..................................... 999 38.6 Unit Heaters ..........................................1000