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RIGHT-SIZED:Equipment and Controls for Super Efficient Buildings|March 9, 2012|
PRESENTERS: Jim Keller, Jay Denny, Russ Landry,Julianne Laue
Funded By: ARRA Funds Energy Resource Manage office
Minnesota
Developed By: In partnership with:
Funded By: ARRA Funds Energy Resource Manage office
Minnesota
Developed By: In partnership with:
Special Thanks to:
Erik Kolderup, PE, LEED APKolderup Consulting
www.kolderupconsulting.com erik@kolderupconsulting.com
(415) 531-5198
3
Learning Objectives
• Right-sizing after applying passive energy conservation strategies
• Utilize controls to optimize the efficiency of equipment
• Energy efficient strategies to maintain occupant comfort
• Understanding energy flows in a building
4
Agenda
• Part 1 (12:30-2:00)– IAQ and Ventilation– Thermal Comfort– HVAC Loads– Energy Flows
• Break• Part 2 (2:10-3:00)
– HVAC System Alternatives– “Right-Sizing” HVAC Components– HVAC Controls– Selecting an HVAC System– The Architect’s Role
• Break• Exercise (3:10-3:40)• Right Sizing in Practice (3:40-4:00)• Case Studies (4:00-4:20)• Wrap Up (4:20-4:30)
5
EnergyFlows
6
Three Key Energy Flow IssuesHeat Flow from One “Thing”
to AnotherMoving Heat from One Place
to Another
Moving Heat “Uphill”
7
Getting Heat from One “Thing” to Another
• Heat Naturally Flows “Downhill” from Hot to Cold– The bigger the temperature difference, the faster the heat
flows– The bigger the area, the faster the heat flows
8
Carrying Heat from One Place to Another
• Heat Carried by Water or Air– Depends on temperature change (TD or T)– Depends on water or air flow rate
Temperature
Ener
gy P
er P
ound
=
9
Carrying Heat from One Place to Another
• Refrigerants--Evaporation(Boiling)/Condensing is “Freeze-Dried” Version– Can carry a lot of energy with
little fluid– Little temperature change needed– Used in Refrigeration systems
(evaporation = boiling)
Temperature
Ener
gy P
er P
ound
Boiling orCondensing
10
Carrying Heat from One Place to Another• Refrigerants—Controlling
Temperature of Heat– Change pressure to control
temperature of evaporation/condensing
– Pressurize to move heat uphill
Pressure
Boiling/Condensation Temperature
11
Carrying Heat from One Place to Another
Temperature
Ener
gy P
er P
ound
Evap
orati
on --
>Pressure
Boiling/Condensation Temperature
Condensation -->
Pressure
Pressure
• Refrigerants—Controlling Temperature of Heat– Change pressure to control
temperature of evaporation/condensing
– Pressurize to move heat uphill
12
Moving Heat “Uphill” (aka Refrigeration)
– Energy must be added to move heat uphill
– That extra energy ends up as more heat
– The farther “uphill” the heat is moved, the more energy it takes
Tem
pera
ture
13
Moving Heat “Uphill” (aka Refrigeration)
Tem
pera
ture
– Energy must be added to move heat uphill
– That extra energy ends up as more heat
– The farther “uphill” the heat is moved, the more energy it takes
14
Moving Heat “Uphill” (aka Refrigeration)
Tem
pera
ture
– Energy must be added to move heat uphill
– That extra energy ends up as more heat
– The farther “uphill” the heat is moved, the more energy it takes
Room Heat Gain & Loss Components
Lighting
Other?
Occupants
Conduction through opaque
envelope
Solar radiation through windows
Conduction through
windows Office equipment
Internal heat gains
External heat gains
Infiltration through cracks
16
Getting Heat Into a Space in a Building:“Typical” Central System
-20°F
0°F
20°F
40°F
60°F
80°F
100°F
120°F
140°F
160°F
180°F
Gas, Coal or Oil3,500 – 4,000F
Boiler Water 180FBoiler
Radi
ator
s
Air H
andl
er/V
AV
Space
Heated Air
Mixed or Cooled Air
Mi x
~350 to 400F
17
Getting The “Rated” Efficiency Out of Condensing Boilers (>90% Efficiency)
Heated Air
75%
80%
85%
90%
95%
100%
80°F 100°F 120°F 140°F 160°F 180°F
Entering Water Temperature
Bo
iler
Eff
icie
ncy
Natural Draft
EnergyStar Min
Condensing Boiler
18
_______ Chart for Showing Moisture in Air Issues
• Curve at Top Shows When Air Can’t Hold Any More Moisture (aka saturated)
• Once At the Top, Cooling More Condenses Moisture Out of Air
Air Temperature
Amou
nt o
f Moi
stur
e (a
ka S
team
) in
Air
140F100F60F
19
Getting The “Rated” Efficiency Out of Condensing Boilers (>90% Efficiency)
Heated Air
75%
80%
85%
90%
95%
100%
80°F 100°F 120°F 140°F 160°F 180°F
Entering Water Temperature
Bo
iler
Eff
icie
ncy
Natural Draft
EnergyStar Min
Condensing Boiler
Direct-Fired Heater
20
_______ Chart for Showing Moisture in Air Issues
• Moisture is Much More Diluted in Direct-Fired Heater
• It Reaches a Lower Temperature, but Never Condenses(THANK GOODNESS!)
Air Temperature
Amou
nt o
f Moi
stur
e (a
ka S
team
) in
Air
140F100F60F
Direct Fired Heater
21
Getting Heat Into a Space in a Building:“Typical” Central System
-20°F
0°F
20°F
40°F
60°F
80°F
100°F
120°F
140°F
160°F
180°F
Gas, Coal or Oil3,500 – 4,000F
Boiler Water 180FBoiler
Radi
ator
s
Air H
andl
er/V
AV
Space
Heated Air
Mixed or Cooled Air
Mi x
~350 to 400F
22
Getting Heat from One “Thing” to Another
• Heat Naturally Flows “Downhill” from Hot to Cold– Via conduction (key in solids), convection (moving gas or liquid),
and/or radiation
– The bigger the temperature difference, the faster the heat flows
– The bigger the area, the faster the heat flows• Moving Heat “Uphill” Takes Energy
– There’s a minimum possible energy required for a given rise in temperature
– The farther “uphill” the heat is moved, the more energy it takes– All Forms of Energy Put into Something Eventually End up as
Heat
23
Central System Designed for Condensing Boilers
-20°F
0°F
20°F
40°F
60°F
80°F
100°F
120°F
140°F
160°F
180°F
Gas at 3,500F
Boiler Water 160F Average
BoilerRa
diat
ors
Space 75F
Heated Air
Mixed or Cooled Air
M ix
Radi
ant
Fl
oor
+
Air
Han
dler
/VAV
24
Central System Designed for Condensing Boilers
-20°F
0°F
20°F
40°F
60°F
80°F
100°F
120°F
140°F
160°F
180°F
Boiler Water 150F Average
Space 75F
60F DropTraditional 20F Drop
25
Getting The “Rated” Efficiency Out of Condensing Boilers (>90% Efficiency)
Heated Air
75%
80%
85%
90%
95%
100%
80°F 100°F 120°F 140°F 160°F 180°F
Entering Water Temperature
Bo
iler
Eff
icie
ncy
Natural Draft
EnergyStar Min
Traditional 20F Drop
60F Drop
26
-20°F
0°F
20°F
40°F
60°F
80°F
100°F
120°F
Getting Heat Into a Space in a Building:Heat Pumps—Air Source & Ground Source
Air Source HP
Space
Heated Air
MixAir Source H
P
Mix
Air Source
27
-20°F
0°F
20°F
40°F
60°F
80°F
100°F
120°F
Getting Heat Into a Space in a Building:Heat Pumps—Air Source & Ground Source
Air Source HP
Space
Heated Air
MixAir Source H
P
Mix
Ground
Air Source Ground Source
Ground Source H
P
Water/Glycol
28
-20°F
0°F
20°F
40°F
60°F
80°F
100°F
120°F
Getting Heat Out of a Space in a Building:Typical Systems
Space
ChillerM ix
Chilled Water
Chiller
Cooled Air
Refrigerant in Chiller
Refrigerant in Chiller
Air CooledHigher Peak Lift
Water CooledLower Peak Lift
Cooling Tower Water
M ix
DX
29
_______ Chart for Showing Moisture in Air Issues
• Air Cooled Refrigerant Loses Heat to Air Temperature
• Evaporation Loses Heat to a Lower Temperature (Wet Bulb)
Air Temperature
Amou
nt o
f Moi
stur
e (a
ka S
team
) in
Air
95F75F55F
30
-20°F
0°F
20°F
40°F
60°F
80°F
100°F
120°F
Getting Heat Out of a Space in a Building:Economizer
Space
M ix
Chilled Water Cooled Air
Refrigerant in Chiller
Recirculated & Cooled Air
Economizer(Outdoor Air)
At Low Temperatures Mixing Outdoor and Room Air Does All Cooling
At Mild Temperatures All Outdoor Air Does Part of Cooling
31
Moving Heat from One Place to Another
Air Water RefrigerantTemperature Drop 20 10 -
Heat Carrying Capacity: BTU per Pound 5 10 50
Fluid Transport Energy Factor: Watts per lb/hr 0.17 0.04 0.27
Heat Transport Enegy Factor: Watts per BTU/hr 35 4 5
32
Water vs. Air
• Water good…– Moving heat via water typically requires less energy– Pipe much smaller than equivalent duct
• But…– Still need ventilation in many cases
• May need a fan and duct anyway
– Air distribution system typically less expensive– Air system can provide “free” cooling with outdoor air