HVAC Systems
Understanding The Basics
Thomas E. Glavinich, D.E., P.E. The University of Kansas
October 22, 2008
SMACNA 65th Annual Convention
Wailea, Maui, Hawaii
HVAC Systems - Understanding The Basics
Manual Objective
Provide an introduction to HVAC
systems for project personnel and
others needing a basic
understanding of HVAC system
operation and components.
HVAC Contractor Defined
HVAC contractor is the firm that
is responsible for the installation
for the complete HVAC system in
accordance with the scope of
work defined by the contract
documents.
HVAC System Contractor
Scope Of Services
z Air Distribution: – Sheet Metal
– Air Distribution Equipment
z Piping z Insulation
z Equipment (Wet) z Water Treatment z HVAC Controls z Test & Balance
HVAC System Contractor:
Advantages
z Establishes Firm As HVAC Expert z Perform All Of CSI Division 23:
– Greater Control Of Scope
– Less Scope Overlaps & Gaps
z Higher On Food Chain: – First Tier Subcontractor
– Closer To $’s
z Potential Higher Profits
z Greater Control Of Schedule & Work Sequence z More Project Opportunities
z More After-Installation Service Opportunities
HVAC System Contractor:
Challenges
z
Increased Contract Size & Scope
zSubcontract Procurement &
Contracting
z
Subcontract Management
z
Wet-Side Equipment Procurement
zMultiple Trade Management
HVAC Systems - Understanding The Basics
Target Audiences
z HVAC Contracting Firms: – Project Managers
– Project Engineers
– Estimators
– Superintendents & Forepersons
– Others
z Construction Programs – Colleges & Universities: – Engineering (Construction Emphasis)
– Construction Science, Management, & Technology
– Other Related Academic Programs
z General Contractors & Construction Managers
HVAC Systems - Understanding The Basics
Intended To Complement
z
HVAC Bid Specifications Manual
z
HVAC Systems Applications
z
SMACNA Guide Specifications
2004 CSI MasterFormat
TMDivision 23 – HVAC
CSI Level 2 Content
23 00 00 HVAC General Requirements 23 10 00 Facility Fuel Systems
23 20 00 HVAC Piping & Pumps 23 30 00 HVAC Air Distribution
23 40 00 HVAC Air Cleaning Devices 23 50 00 Central Heating Equipment 23 60 00 Central Cooling Equipment 23 70 00 Central HVAC Equipment
23 80 00 Decentralized HVAC Equipment
HVAC Systems Applications
I Introduction II Basic HVAC Systems III HVAC Control Systems IV Multizone Systems V Dual-Duct Systems VI Terminal Reheat Systems VII Variable Air Volume Systems VIII Induction & Induction Reheat Systems IX Special Applications
X Hydronic Systems
XI Unitary & Heat Pump Systems XII Cooling/Refrigerant Systems XIII Hydronic Heat Recovery Systems XIV Engineering Data, Tables & Charts
HVAC Systems: Understanding The Basics
How Will This Manual Be Used?
z
Chapter Education Program
z
Self Study
z
Reference
z
Text: Primary Or Supplemental
z
Combination
HVAC Systems: Understanding The Basics
Chapter Outline
I Introduction To HVAC Systems II Properties Of Moist Air
III HVAC System Basics IV Unitary HVAC Systems V Central Heating Equipment VI Central Cooling Equipment VII Hydronic Distribution Systems VIII Air Distribution Systems
IX Central HVAC Systems X Control Systems
HVAC Systems: Understanding The Basics
Chapter I - Intro To HVAC Systems
1.1 Introduction
1.2 What Is An HVAC System?
1.3 Why Do Buildings Need HVAC?
1.4 A Brief History Of HVAC Systems
1.5 HVAC Systems & 21st Century Buildings
1.6 Overview Of This Manual
HVAC Systems: Understanding The Basics
Chapter II - Properties Of Moist Air
2.1 Introduction2.2 Air Chemistry 2.3 Air Temperature 2.4 Air Humidity
2.5 Evaporation & Condensation 2.6 Moist Air Properties
2.7 Psychrometry
2.8 Heat Transfer Methods 2.9 Heat Transfer Units 2.10 Heat Transfer Media 2.11 Moist Air Energy Content
2.12 Simple Space Conditioning Processes 2.13 Practical Space Conditioning Processes
Air Temperature
z
What Is Temperature?
z
Temperature Scales
z
Temperature Measurement
Air Humidity
z
What Is Humidity?
z
Humidity Scales
z
Humidity Measurement
Psychrometric Chart
Moist Air Physical Properties
z
Dry-Bulb (DB) Temperature
z
Wet-Bulb (WB) Temperature
z
Percent Relative Humidity
z
Humidity Ratio
z
Dew Point Temperature
Moist Air Energy Content
z
Sensible Heat
z
Latent Heat
z
Enthalpy
Basic Space Conditioning
Processes
z
Sensible Cooling
zSensible Heating
zHumidifying
zDehumidifying
z
Cooling & Dehumidifying
zHeating & Humidifying
zChemical Dehumidifying
zEvaporative Cooling
Simple Space
Conditioning Processes
HVAC Systems: Understanding The Basics
Chapter III - HVAC System Basics
8.1 Introduction
8.2 HVAC System Purpose 8.3 HVAC Zones & Spaces 8.4 Airflow Defined
8.5 Four Variables The Impact Human Comfort 8.6 Defining Human Comfort
8.7 Indoor Air Quality
8.8 HVAC System Energy Use 8.9 HVAC System Operation
8.10 Basic HVAC System Mechanical Elements 8.11 HVAC Controls
8.12 Space Conditioning Methods Used By HVAC Systems 8.13 HVAC Sys Categorized By Primary Heat Transfer Media 8.14 HVAC System Space Conditioning Methods & Categories 8.15 HVAC System Equipment Location & Heat Transport
Four Variables That Affect
Human Thermal Comfort
z
Temperature
z
Thermal Radiation
z
Humidity
z
Air Speed
American Society of Heating, Refrigerating, and
Air-Conditioning Engineers, Thermal Environmental Conditions for
Human Occupancy, ASHRAE 55-2004.
ASHRAE Comfort Zones
HVAC System Energy Use
z
HVAC System Energy Use
z
ASHRAE/IESNA Standard 90.1
zEnergy Codes & Standards
z
Green Buildings & HVAC Energy Use
Basic HVAC System Elements
z
Thermal Conditioner
z
Moisture Controller
z
Air Mover
Basic HVAC System Elements
Space Conditioning Methods
z
Constant Air Volume - Variable Temperature
zVariable Air Volume - Constant Temperature
zVariable Air Volume - Variable Temperature
HVAC Systems: Understanding The Basics
Section 3.13 - Primary Heat Xfer
zAll-Air HVAC Systems
z
Air-Hydronic HVAC Systems
zAll-Hydronic HVAC Systems
zDirect Refrigerant HVAC Systems
zHybrid HVAC Systems
Air-Hydronic HVAC System
HVAC Systems: Understanding The Basics
Chapter IV - Unitary HVAC Systems
4.1 Introduction
4.2 Unitary HVAC Systems Characteristics & Use 4.3 Refrigeration Defined
4.4 The Refrigeration Cycle
4.5 Direct Expansion Refrigeration Systems 4.6 Unitary HVAC System Types
HVAC Systems: Understanding The Basics
Section 4.5.2
Six Primary DX System Components
z
Compressor
z
Condenser Coil
z
Regulator Valve
z
Evaporator Coil
z
Refrigerant Piping
z
Controls
HVAC Systems: Understanding The Basics
Section 4.6 - Unitary HVAC Systems
z
Packaged Terminal HVAC Units
zRoom Air Conditioners
z
Self-Contained Air Conditioners
zComputer-Room Air-Conditioners
zSplit-System Air-Conditioners
zAir-Source Unitary Heat Pumps
zWater-Source Unitary Heat Pumps
HVAC Systems: Understanding The Basics
Chapter V - Central Heating Equipment
5.1 Introduction 5.2 Furnaces 5.3 Boilers 5.4 Boiler Sizing 5.5 Boiler Construction 5.6 Electric Boilers 5.7 Condensing Boilers
5.8 Boiler Auxiliary Equipment 5.9 Boiler Controls
5.10 Boiler Water Treatment
5.11 Solar Energy Heating Systems 5.12 Combined Heat & Power
HVAC Systems: Understanding The Basics
Chapter VI - Central Cooling Equipment
6.1 Introduction
6.2 Central Cooling Plant Operation & Components 6.3 Chiller Purpose
6.4 Refrigeration Cycle 6.5 Refrigerant
6.6 Motor-Compressor Units
6.7 Mech Compressor Operation & Characteristics 6.8 Absorption Chillers
6.9 Cooling Towers
Central Cooling Plant
Schematic Diagram
HVAC Systems: Understanding The Basics
Chapter VII - Hydronic Distribution Sys
7.1 Introduction
7.2 Hot Water Distribution System Operation 7.3 Chilled Water Distribution System Operation 7.4 Hydronic Distribution System Operating Temps 7.5 Hydronic Distribution System Arrangements 7.6 Multi-Loop Hydronic Distribution System 7.7 Hydronic Distribution System Heat Xfer Mode 7.8 Convection Terminal Units
HVAC Systems: Understanding The Basics
Section 7.5
Hydronic Dist Sys Arrangements
z
One-Pipe System
z
Two-Pipe System
z
Three-Pipe System
z
Four-Pipe System
z
Summer-Winter System
Two-Pipe Hydronic Distribution
(Direct Return)
HVAC Systems: Understanding The Basics
Section 7.8
Convection Terminal Units
z Air-Coil Units z Fan-Coil Units z Induction Units z Unit Ventilators z Radiators
z Finned-Tube Radiation Heaters z Valence Units
z Convectors z Unit Heaters
HVAC Systems: Understanding The Basics
Chapter VIII - Air Dist Systems
8.1 Introduction
8.2 Air Distribution System Purpose 8.3 Air Distribution System Components 8.4 Fans
8.5 Air Handling Units 8.6 Air Ducts & Plenums 8.7 VAV Terminal Units 8.8 Air Outlets & Inlets
8.9 Air Distribution System Operation 8.10 Air Distribution System Operating Point 8.11 Air Distribution System Dynamics 8.12 System Operating Point & Fan Speed 8.13 Variable Frequency Drives
8.14 Air Cleaning Devices
HVAC Systems: Understanding The Basics
Chapter IX - Central HVAC Sys
9.1 Introduction
9.2 Central HVAC Subsystems
9.3 VAV System Description
9.4 VAV System Operation
9.5 VAV Terminal Operation
9.6 HVAC Systems Incorporating VAV
9.7 Constant Volume HVAC Systems
9.8 VAV Versus Constant-Volume
Basic Single-Zone Cooling
Only VAV System
HVAC Systems: Understanding The Basics
Chapter X - Control Systems
10.1 Introduction
10.2 Control System Purpose 10.3 Control System Types
10.4 Control System Components
10.5 Thermostat: Simple Control System 10.6 Sensors
10.7 Controllers
10.8 Controlled Devices
10.9 Building Automation & Control Systems 10.10 Open-Architecture Control Systems
HVAC Systems: Understanding The Basics
