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Understanding HVACPart One
Agenda
Introductions
Rules of Engagement
HVAC Basics
Systems & Components
Measurement & Control
Energy Consumption
The Future?
Maintenance Strategies
CMMS
Questions & Evading Answers
Understanding HVAC, Part One & Two
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Ed Butzen
Manager of Custodial Services and SitesGreen Bay School District
Tina Brueckner
Service Manager Johnson Controls, Appleton Office
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Rules of Engagement
Silence your cell phone/pager.
Don’t wait to ask questions.
If we don’t finish, we don’t finish (10 minutes for Q&A)
Tell me what you want to know.
No side conversations.
There won’t be a test (until you get back to the district)
HVAC Basics
Why not just open a window?
HVAC Vocabulary
Technical Evolution
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Students in well-maintained facilities score 11% higher on standardized tests.
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Main purpose of HVAC (heating, ventilating, and air conditioning) systems is to provide occupants with "conditioned" air so that they will have a comfortable and safe work (learning) environment
"Conditioned" air means that air is clean and odor-free, and the temperature, humidity, and movement of the air are within certain comfort ranges
What about the “V” in HVAC?
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HVAC Basics
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HVAC Vocabulary
Measurable Parameters
Temperature (Dry Bulb/ Wet Bulb)
Pressure
Humidity
Indoor Air Quality (CO, CO2, odor, VOC’s, particulate, etc.)
Air Changes/Air Flow
Phase
kWh/ft2, BTU/ft2
British Thermal Unit (Btu) = Heat required to raise 1 lb of water 1 degree F
Ton of Cooling = Heat required to melt 2000 lb of ice in 24 hours (12,000 Btu/hr)
$/ft2 Psychometric Chart
Maintenance Strategies
Reactive
Preventive
Predictive
Condition-Based, Reliability-Based, Knowledge-Based, Buzz-Word-of-the-Month-Based
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Technical Evolution
Rugged mechanicals, not control
Controllable mechanicals, pneumatic controls
High efficiency mechanicals, direct-digital controls
“Green” mechanicals, web-based & wireless controls
Fully integrated systems
Heating
Cooling
Lighting
Security
Fire Safety
Telecommunications
Information Technology
HVAC Basics
Laws of Thermodynamics
Applications of Thermodynamics in K-12
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Laws of Thermodynamics
Zeroth law of thermodynamics, stating that thermodynamic equilibrium is an equivalence relation.
If two thermodynamic systems are separately in thermal equilibrium with a third, they are also in thermal equilibrium with each other.
First law of thermodynamics, about the conservation of energy
The change in the internal energy of a closed thermodynamic system is equal to the sum of the amount of heatenergy supplied to the system and the work done on the system.
Second law of thermodynamics, about entropy
The total entropy of any isolated thermodynamic system tends to increase over time, approaching a maximum value.
Third law of thermodynamics, about absolute zero temperature
As a system asymptotically approaches absolute zero of temperature all processes virtually cease and the entropy of the system asymptotically approaches a minimum value; also stated as: "the entropy of all systems and of all states of a system is zero at absolute zero" or equivalently "it is impossible to reach the absolute zero of temperature by any finite number of processes".
Onsager reciprocal relations (sometimes called the Fourth Law of Thermodynamics)
Express the equality of certain relations between flows and forces in thermodynamic systems out of equilibrium, but where a notion of local equilibrium exists.
Attributed to Arnold Sommerfeld:
“Thermodynamics is a funny subject. The first time you go through it, you don't understand it at all. The second time you go through it, you think you understand it, except for one or two small points. The third time you go through it, you know you don't understand it, but by that time you are so used to it, it doesn't bother you any more.
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Systems & Components
Heating
Cooling
Air Handling
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System Types & Common Terms
Unitary Equipment
Direct Expansion
Split System
Heat Pump
Packaged Rooftop Unit (RTU)
PTAC/PTHP
Hydronic
Boiler
Chiller
2 Pipe/4 Pipe System
Other
Water Loop Heat Pump
Radiant
Air Distribution
Constant Volume
Variable Air Volume (VAV)
Ductwork
Terminals/Fan Box
Dampers
Controls
Pneumatics
Direct Digital Controls (DDC)
Thermostats
Hydronic Systems
Hydronics is the name for the use of water as the heat-transfer medium in heating and cooling systems.
Water has a higher specific heat capacity than water, reducing size of heat/cool delivery system.
Water valves v. dampers for control
Heating Systems
Boilers, Pumps, Heat Exchangers
Cooling Systems
Chillers, Pumps, Cooling Towers, Heat Exchangers
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Heating Systems – Steam
Boilers
Converters/Coils
Steam Cycle
Steam Traps
Heating Systems – Steam
Boilers
Converters/Coils
Steam Cycle
Steam Traps
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Heating Systems – Hot Water
Condensing
Non-Condensing
Water tube
Heating Systems – Hot Water
Centrifugal Pumps
Valves
Heat Exchangers
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Basic Refrigeration Cycle
Expansion Valve
Compressor
Evaporator
Condenser
Cooling Systems
Water Cooled Chillers
Cooling Towers
Air Cooled Chillers
Direct Expansion/Condensing Units
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Unitary Equipment
Pre-Engineered, Factory Assembled, Site Hook Up
Window AC Units
Packaged Terminal AC (PTAC)
Rooftop Units (RTU’s)
Hybrid Heating/Cooling—Water Loop Heat Pump
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Hybrid Heating/Cooling—Water Loop Heat Pump
Airside Systems
Air Handlers
Univents
Rooftop Units (RTU’s)
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Other HVAC Equipment
Warm Air Furnace
Unit Heaters
Radiant Heating (Direct & Indirect-Fired)
Air Distribution
Constant VolumeVariable Air Volume (VAV)DuctworkTerminals/Fan BoxDampers
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Air Distribution
DuctworkMetalFlexibleDuctboard
Grilles, Louvers, & RegistersDampers
Shut offFireSmoke
SealantsSupports
Measurement & ControlElectric
Pneumatic
Direct Digital
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Controls Network
Controls Network
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Controls Network
Energy Consumption
Electricity
Natural Gas
Water
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Boiler Economics
100,000 SF Building
2—2.0 MMBtu/hr HW Boiler @ 85% Eff.
EFLH = 1500 Hr
2.0 MMBtu/hr x 1500 hr x $1.00/therm
= $30,000/year
Steam Versus Hot Water
15 PSIG steam is 250 F
100 F delta T for exhaust stack—350 F!
Combustion Efficiency = 80%
Hot water can range 135 F – 180 F, reset to outdoor air temperature
100 F delta T for exhaust stack—235 F! (condensing boiler?)
Combustion Efficiency = 85% (92%)
Significant fuel savings (5.9%) on shoulder heating days
Reduced chemical costs/boiler blowdown
Reduced steam loss from bad steam traps
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Chiller Economics
100,000 SF Building
1—250 Ton Chiller @ 0.50 kW/ton
EFLH = 1000 hours (50%)
Chiller250 Ton x 0.5 kW/ton x 1000 hr x $0.06/kWh =$7,500
250 Ton x 0.5 kW/ton x 5 mo x $10/kW/mo =$5,000
Pumps250 Ton x 0.08 kW/ton x 2000 hr x $0.06/kWh =$2,400
Tower250 Ton x 0.15 kW/ton x 2000 hr x $0.06/kWh =$4,500
Chemicals =$1,000
Total =$20,400
Rooftop AC Unit Economics
100,000 SF Building
12—25 Ton RTU @1.2 kW/ton
EFLH = 1000 hour
12 x 25 ton x 1.2 kW/ton x 1000 hr x $0.06 =$45,000
12 x 25 ton x 1.2 kW/ton x 0.8 DF x 5 mo x $10/kW =$14,400
Total $59,400
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Ground Source Heat Pumps
Air conditioning rejects heat to summer air at 85-95F
Heat pump extracts heat from winter air at 30-35F
Soil maintains constant temperature of 50-55F below 5 feet
GSHP is very efficient and should extend equipment life
Circulate water/glycol to well field to reject/extract heatSoil conditions must have adequate moisture/flow
Load must be balanced or residual build upCannot be cooling-only or heating-only
Negatives?
Maintenance
Noise
Ventilation
20.0
40.0
60.0
80.0
100.0
120.0
140.0
1880 1900 1920 1940 1960 1980 2000
Year Built
Site
Ene
rgy
(kB
tu/s
f)
Focus on EnergyBenchmarking Energy Use in Wisconsin Schools
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Classic Problems
Where is the fresh air intake?
Where does the delivery van park with its motor running?
Where is the designated smoking area for the building?
The Future (now)
Renewable Energy
LEED Certification
Carbon Footprinting
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Hot Buttons
Mold Legionnaires' Disease
CO Safety
IAQ Frozen Coils
Boiler Failures CFC Phase Out
Global Warming HCFC-22 Phase Out
Questions and Answers
HVAC Part 2 is coming up in the next session.
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Understanding HVAC
Maintenance Strategies
Staffing Qualification
CMMS
Master Planning
Questions and Evading Answers
Part Two
Total Cost of Operation
ASHRAE – American Society for Heating, Refrigeration & Air Conditioning Engineers
Operation50%
Construction11%
Financing14%
Alterations25%
Operations Budgets
Capital Budgets
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Maintenance Strategies
The History of Maintenance Evolution
Fitting the Right Strategy
In a Perfect World…..
Students in well-maintained facilities score 11% higher on standardized tests.
A well-structured maintenance strategy will allow district administration to make informed decisions concerning:
Facility maintenance programs
Productivity processes
Resource allocation
Decisions will be made about these with or without the proper tools.
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Maintenance – Ensuring that physical assets continue to do what their users want them to do.
Reliability-centered Maintenance – A process used to determine what must be done to ensure that any physical asset continues to do what its users want it to do in its present operating context.
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The Evolution of Maintenance Strategies
1900’s
Reactive
1960’s
Preventive
Preventive Weakness
“The best time to determine how well a piece of equipment is running is when it is running”.
“Prevention tasks are almost always performed when the equipment is down and most detection tasks are performed when the equipment is running”.
J. Richard Word, CMRP, 2004
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1900’s
Reactive
1960’s
Preventive
1980’s
Predictive
The Evolution of Maintenance Strategies
WAVEFORM DISPLAY 02-Aug-00 14:49:35 RMS = 1.89 PK(+) = 10.78 PK(-) = 13.55 CRESTF= 7.16
0 40 80 120 160
-15-12-9-6-30369
Time in mSecs
Acc
eler
atio
n in
G-s
001 - Exhaust Fan EF-3EF-3 -M2H Motor Inboard Horizontal
ROUTE SPECTRUM 02-Aug-00 14:49:35 OVRALL= .1321 V-DG PK = .1318 LOAD = 100.0 RPM = 1785. RPS = 29.74
0 30 60 90 120 150
0
0.01
0.02
0.03
0.04
0.05
Frequency in kCPM
PK V
eloc
ity in
In/S
ec
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001 - Air Handling Unit 5AHU-5 -M1A Motor Outboard Axial
Time in mSecs
Acc
eler
atio
n in
G-s
0 40 80 120 160
PlotSpan
-15
15
15-Jul-04 12:18
14-May-04 10:36
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Spectroscopic Analysis
Date 9/22/2004 8/19/2004 7/22/2004 5/13/2004
Lab No. 206227 204170 202511 198382
Iron 267 454 1122 2979
Chrome 3 6 13 33
Nickel 8 41 108 108
Copper 25 118 216 274
Lead 9 4 4 4
Tin 0 0 1 1
Silver 0 0 0 0
Aluminum 8 9 57 102
Silicon 55 216 607 1668
Sodium 7 0 7 18
Boron 24 3 12 17
Molybdenum 1 1 1 2
Magnesium 5 4 15 18
Calcium 268 125 237 224
Barium 0 0 0 1
Phosphorous 246 420 380 475
Zinc 34 428 212 135
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1900’s
Reactive
1960’s
Preventive
1980’s
Predictive
1990’s
CBM
The Evolution of Maintenance Strategies
Criticality Matrix
Area Served Risk Mechanical History
Classroom 10 School's Out 10 High 10
IT 10 Injury 7 Above Average 7
Communication 5 Safety 5 Average 5
Environ. Support 3 Comfort 3 Below Average 3
Equip. Support 2 Minimal Risk 2 None/Low 1
% Asset Life Aged O&M Costs Redundancy
More than 100% 10 Level 4 10 None 10
95-100% 7 Level 3 7 Seasonal 7
85-95% 5 Level 2 5 Shared 5
50-85% 3 Level 1 3 1 Spare 2
0-50% 2 Generalist 1 More than 1 Spare 1
PdM/PM/Inventory 25-50
PM/Inventory 15-24
Inventory only 10-14
No activity 0-9
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Fitting the Right Strategy
• Maintenance-preventable failures only
• Critical systems/components only
• Model should account for lost revenue opportunities
• Easily accessible data
• Not an accounting procedure
The Reliability Maintenance Model
1. Would the maintenance change produce a significant improvement in reliability and downtime?
2. What value would this add to the organization in relation to the current value of the asset?
3. What other areas might be addressed before the maintenance activity is improved?
4. What should be measured to monitor asset value and maintenance effectiveness going forward?
The Reliability Maintenance Model
Fitting the Right Strategy
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Computerized Maintenance Management SoftwareOperability
Initial Set-Up
CMMS
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CMMS
CMMS
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CMMS
Specific Outcomes
Well-defined nomenclature
Extended timelines
Long-term payback
Get the vendor to do most of the work
Look for ease of use – don’t try rocket science
Work with service providers – get them in ‘the system’
Find internal advocates – sometimes you ‘make’ one
Questions and Answers
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Thank You
