8/3/2019 0 Overview of Hvac Systems Jk Means
1/43
1
INTRODUCTION
TO HVAC SYSTEMDESIGN FOR
ARCHITECTS
Presented initially on Feb. 11-12, 2004 and annually thereafter in Lear
Auditorium at Lawrence Technological University, Southfield, Michigan
Prepared by Prof Janice K. Means, PE, LEED AP
8/3/2019 0 Overview of Hvac Systems Jk Means
2/43
2
So what is behind those
walls, above our headsand below our feet that
has so much to do with
making us comfortable
in buildings?
8/3/2019 0 Overview of Hvac Systems Jk Means
3/43
3
and what do
architects need toknow about these
heating, ventilatingand air-conditioning
(HVAC) systems?
8/3/2019 0 Overview of Hvac Systems Jk Means
4/43
4
Buildings consume 50%of the worlds energy.
--quote from Keynote Address given by Susan S. Szenasy(Editor In Chief of Metropolis) at the ACSA/AIA Teachers
Seminar at Cranbrook Academy of Art in Bloomfield Hills, MI
in June, 2003
*Note that some experts cite lower percentages for the
portion of energy used by buildings in the United States.
8/3/2019 0 Overview of Hvac Systems Jk Means
5/43
5
According to the DOE , buildings in
the U.S. use varying percentages of
their total energy use to provide
comfort heating and cooling for
occupants.
56% in private homes 38% in multi-family residences
52% in schools (K-12) 37% in universities
41% in government buildings 34% in offices
40% in retail structures 28% in health care structures
22% in hotels motels
8/3/2019 0 Overview of Hvac Systems Jk Means
6/43
6
There are about 5
million commercialbuildings in the
United States.
--www.sustainableenergy.org
8/3/2019 0 Overview of Hvac Systems Jk Means
7/43
7
Office
Equipment
16%
Hot Water
9%
Ventilation
5%
Space
Cooling
9%
Space
Heating25%
Lighting
29%
Misc.
7%
Office BuildingEnergy Use
www.eere.energy.gov/buildings/index.cfm?flash=yes
8/3/2019 0 Overview of Hvac Systems Jk Means
8/43
8
What is the architects rolein creating a comfortable
environment for occupantswhile effecting responsible
energy use?
Isnt up to the mechanicalengineer?
8/3/2019 0 Overview of Hvac Systems Jk Means
9/43
9
Even a superior HVAC systemcannot compensate for a poorly
designed building
one where not enough
mechanical space has beenprovided
or which is an energy hog.
8/3/2019 0 Overview of Hvac Systems Jk Means
10/43
10
So now lets talk aboutwhat you need to know
about HVAC equipmentand its design.
8/3/2019 0 Overview of Hvac Systems Jk Means
11/43
11
Major SystemComponents in HVAC
Systems
Energy ConversionEquipment
Distribution Equipment
Control Equipment
8/3/2019 0 Overview of Hvac Systems Jk Means
12/43
12
Energy Conversion Equipment:
converts fuel to heat (or cool)
Examples: chilled watercondensers, chillers, boilers,
furnaces, domestic hot waterheaters, etc.
Major System Components in HVAC Systems
8/3/2019 0 Overview of Hvac Systems Jk Means
13/43
13
Distribution Equipment:
transports fluid holding heat(or cool) to/away from
conditioned space
Examples: ducts & plenums
with fans or pipes with pumps
Major System Components in HVAC Systems
8/3/2019 0 Overview of Hvac Systems Jk Means
14/43
14
Control Equipment
Sensors to measure temperature,
humidity, purity levels, etc.
Senders to relay measured/sensed
information to/from controller device Software w/ hardwareto monitor
and change conditions
Examples: thermostats & humiditysensors; wires & pneumatic hoses;
controllers, BAS, EMS, etc.
Major System Components in HVAC Systems
8/3/2019 0 Overview of Hvac Systems Jk Means
15/43
15
Major HVAC Systems
1. All Air
2. Air & Water
3. All Water
4. Unitary
5. RadiantPanels
H/C Equipment
Centrally Located
w/
Air-Handling
Central or By Floor
H/C Equipment
Adjacent to Zone
8/3/2019 0 Overview of Hvac Systems Jk Means
16/43
16
All Air Cooling is always done from a central air
stream
Heating is done from the central air
stream, & sometimes at azone (reheat)
Hot water loops from boilers to heating
coils in air stream &, sometimes at zone
Cold water loops from chillers or
condensers to cool coils in the air stream
Air is provided atConstant Volume (vari-
able temperature) orVariable Air Volume
(constant temperature)
Major HVAC Systems
8/3/2019 0 Overview of Hvac Systems Jk Means
17/43
17
All AirMajor types of ALL AIR systems
(many variations)
Single Zone
Terminal Reheat* Single Duct VAV
Dual Duct
Multi-zone
*Shown combined with a Single Duct VAV
in following diagrams.
Major HVAC Systems
8/3/2019 0 Overview of Hvac Systems Jk Means
18/43
18
All Air SystemsMajor HVAC Systems
Re-heat coil
Pre-heat coil
Filter(s)
Cooling coil
Fan
Every ALL AIR system has these components, however,those in redmay be arranged differently.
E.A.(exhaust air)or relief air to
outdoors
O.A. outsideair through
louvers
R.A.
One or more
ducts provide
S.A.
(supply air) toconditioned
space
R.A. (return air)
from conditioned space
Air Handling Unit
8/3/2019 0 Overview of Hvac Systems Jk Means
19/43
19
All Air Systems
Major HVAC Systems
Boiler
Chiller
Fan
Re-heat coil
R.A.
Pre-heat coil
Filter
RA
O.A.
E.A.
SACooling coil T
Single Zone System
CV (typically)
8/3/2019 0 Overview of Hvac Systems Jk Means
20/43
20
Major HVAC Systems
All Air Systems
Single Duct Variable Air Volume
with variations
Pre-heat coil
Boiler
Chiller
Fan
Re-heat coil
R.A.
Filter
RA RA
O.A.
E.A.
o o o o o
o o o o o
VAV Boxes
(optional fan for fan-powered VAV &
optional Reheat coilfor Terminal Reheat)
SA SA
Cooling coil
TT
VAV
8/3/2019 0 Overview of Hvac Systems Jk Means
21/43
21
Major HVAC Systems
All Air Systems
Chiller
Fan
Heating coilsPre-heat coil
Filter
E.A.
Cooling coils
Mixingbox
Boiler
O.A.T
CV shown (or VAV)
Dual Duct Air System
8/3/2019 0 Overview of Hvac Systems Jk Means
22/43
22
Major HVAC Systems
Multi-Zone System
Boiler
Chiller
Fan
Heating coils
Pre-heat coil
Filter
O.A.
E.A.
Cooling coils
Mixing controls
T
T
T
All Air Systems
CV shown (or VAV)
8/3/2019 0 Overview of Hvac Systems Jk Means
23/43
23
ALL WATER systems will be
discussed prior to
AIR & WATER systems.
Major HVAC Systems
8/3/2019 0 Overview of Hvac Systems Jk Means
24/43
24
All Water
Major types of ALL WATER systems
Two Pipe
Four Pipe
Major HVAC Systems
8/3/2019 0 Overview of Hvac Systems Jk Means
25/43
25
All Water
Able to only heat and cool
Cannot provide humidification
Air quality provided by
windows, separate system, or
through unit ventilators
Water is delivered from centralequipment, e.g., boiler or chiller
Major HVAC Systems
8/3/2019 0 Overview of Hvac Systems Jk Means
26/43
26
All WaterMajor HVAC Systems
Refrigeration
Machine
Boiler pumps
Fan Coil Unit Shown
(can be convector or unit ventilator)
Valves* switch seasonally betwee
boiler and refrigeration machine
for ONLY COOLING or
ONLY HEATING at one time2-Pipe System
T T T
* Actual connections not shown.
8/3/2019 0 Overview of Hvac Systems Jk Means
27/43
27
All WaterMajor HVAC Systems
Refrigeration
Machine
Boiler pump
T
4-way valveFan Coil Unit
COOLINGHEATING
4-Pipe System
T T
8/3/2019 0 Overview of Hvac Systems Jk Means
28/43
28
Air & Water
Major types of Air & Water systems
Induction
Fan Coil with Supplementary Air
Radiant Panels with
Supplementary Air
Major HVAC Systems
8/3/2019 0 Overview of Hvac Systems Jk Means
29/43
29
Air & Water
Most heating and cooling is
provided by the water (hydronic)
system
The air portion of the combined
system need not be as large as for an
all air system because it is justsupplying ventilation air (and
sometime humidification)
Major HVAC Systems
8/3/2019 0 Overview of Hvac Systems Jk Means
30/43
30
Air & WaterMajor HVAC Systems
Induction System
T
Room air is
induced intoterminal unit
Chiller
Pre-heat coil
Filter
Boiler
100%
O.A.
Fan
Re-heat coilCooling coil
TerminalRoom Unit
8/3/2019 0 Overview of Hvac Systems Jk Means
31/43
31
Air & WaterMajor HVAC Systems
Chiller
Pre-heat coil
Filter
Boiler
100%O.A.
Fan
Re-heat coilCooling coil
TerminalRoom Unit
Fan in Terminal
Unit pulls air in fromroom and assists
central fan
Fan Coil with Supplementary Air
T
8/3/2019 0 Overview of Hvac Systems Jk Means
32/43
32
Air & WaterMajor HVAC Systems
Radiant Panel with Supplementary Air
Chiller
Pre-heat coil
Filter
Boiler
O.A.Fan
Re-heat coil
Cooling coil
Wall or Ceiling
Mounted RadiantPanel
E.A.T
8/3/2019 0 Overview of Hvac Systems Jk Means
33/43
33
Major HVAC Systems
Unitary SystemsMajor types of Unitary systems
Packaged Units roof or groundmounted factory assembled
Split SystemsAir coil condenser outside
& AHU in ceiling, e.g., residential air-conditioning
PTAC (Packaged Terminal ConditioningUnits), e.g., window air-conditioner
(Only packaged units will be discussed in this
presentation.)
8/3/2019 0 Overview of Hvac Systems Jk Means
34/43
34
Packaged Units Packaged units contains:
fans, coils and filters (AHU-function)
refrigerant compressor & condenser
controls
Energy
conversion &distribution
equipment are
housed in the
same package
Ducts are run directly from the units to the area to
be conditioned. Typically, separate units serve each
zone.
Major HVAC Systems Unitary Systems
8/3/2019 0 Overview of Hvac Systems Jk Means
35/43
35
Radiant PanelsMajor types of Unitary systems
Air-heated or air-cooled panels suppliedby air heated/cooled indirectly by a boiler,
chiller or refrigerant compressor.
Hydronic (water-heated) panels
containing embedded or mounted pipes or
tubes which can be mounted.
Electric (resistance-heated wires) panels
Major HVAC Systems
8/3/2019 0 Overview of Hvac Systems Jk Means
36/43
36
Often installed with central systems
(as discussed in the Air & Water system
section)
Also available in packaged panels
ready to mount or hang, and powered bynatural gas or electricity
Electric panels are sometimes used forspot heating in residential
(This presentation will not elaborate further on radiant panels.)
Major HVAC Systems Radiant Panels
8/3/2019 0 Overview of Hvac Systems Jk Means
37/43
37
Systems Most Commonly Usedin Commercial Structures
All Air
Air & Water
Unitary Packaged Units
8/3/2019 0 Overview of Hvac Systems Jk Means
38/43
38
Central Systems
require 1 or moreequipment room(s) in
basement, penthouse or
roof & fan rooms in 1 or
more areas
have extensive
distribution systems
require complex
controls
Systems Most Commonly Used in Commercial Structures
Packaged Systems
have equipmentdistributed throughout
building (or overhead
on roof of low-rise
structures)
require minimal
distribution systems
need only simplified
controls
Comparisons of Central & Local Systems
S C l d C l S
8/3/2019 0 Overview of Hvac Systems Jk Means
39/43
39
Systems Most Commonly Used in Commercial Structures
Comparisons of Advantages of Central& Local Systems
Central System Advantages
easier to control/maintain IAQ
more flexibility in locating
ventilation intake locations
waste heat energy can more
easily be recovered & used by
another process
equipment easier to maintain w/o
interrupting occupants
noise & waste heat easier to
control
Local System Advantages
doesnt require majormechanical areas w/in building
more energy efficient in
responding to scheduling &
diversity variations
system breakdowns do not take
down entire building
simple operating controls
S M C l U d i C i l S
8/3/2019 0 Overview of Hvac Systems Jk Means
40/43
40
Systems Most Commonly Used in Commercial Structures
Comparisons of Central & Local Systems
Central System Disadvantages
entire building affected
if major piece of
equipment goes down
requires space for
large distribution
systems
energy may be wasted
if entire building or
major zone must be
conditioned for a smallarea
easier to provide
smoke control if fire
Local System Disadvantages
noise is harder to control
since equipment is locatedcloser, or within, occupied
spaces
more difficult to harvest waste
heat maintenance is demanding &
may disrupt occupants
poorer IAQ since numerous
filters must be maintained
use in interior zones prevents
needed access to outdoor air
more difficult to control smoke
during fire
8/3/2019 0 Overview of Hvac Systems Jk Means
41/43
41
Summary
Hopefully, some of the mystery behindHVAC systems and implications for
design to optimize HVAC effectiveness
has been gleaned from this
presentation. Sources for additional
information and direction follow.
###
8/3/2019 0 Overview of Hvac Systems Jk Means
42/43
42
Studio Companion, by Edward Allen, 1989,by John
Wiley & Sons
www.ashrae.org: home for the American Societyof Heating, Refrigerating and Air-Conditioning
Engineers, a standards-writing professional
society for HVAC and Refrigeration.
www.usgbc.org: home of the United States
Green Building Council (LTU is a new member),
group promoting sustainable architecture anddevelopers of the sustainability standard, LEED,
Leadership in Energy & Environmental Design.
For More Information
8/3/2019 0 Overview of Hvac Systems Jk Means
43/43
43
Prof. Janice K. Means, PE, LEED APCollege of Architecture and Design
Lawrence Technological University,
Southfield, Michigan 48075Office A-217 248.204.2852
For More Information,contact
###