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CHOOSING BY ADVANTAGESAPPLYING A SOUND DECISION MAKING METHOD
TO CHOOSE AN HVAC SYSTEM
ASHRAE ILLINOIS 2020 SPRING CONFERENCETRACK #1, SPECIALTIES 101
Cindy Cogil, PE, LEED AP BD+C
Principal, SmithGroup
LEARNING OBJECTIVES
Objective 1: Understand what constitutes a sound decision.
Objective 2: Learn the vocabulary of “Choosing by Advantages.”
Objective 3: Learn how to apply CBA to HVAC System Selection.
2 smithgroup.com
ASHRAE is a Registered Provider with The American Institute of Architects Continuing Education
Systems. Credit earned on completion of this program will be reported to ASHRAE Records for AIA
members. Certificates of Completion for non-AIA members are available on request.
This program is registered with the AIA/ASHRAE for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or
endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific
materials, methods, and services will be addressed at the conclusion of this presentation.
OVERVIEW
UNSOUND DECISION MAKING
Unsound Decision Making:
— Weighs advantages and disadvantages
— Weighs attributes (i.e., pros and cons)
— Weighs factors, criteria, goals, roles, categories, objectives
4
SOUND DECISION MAKING
Decisions must be based on the importance of advantages
Sound methods anchor decisions to relevant facts
5
CHOOSING BY ADVANTAGES
Why
— Allows for clear and transparent decision making
— Aligns with values and culture of Lean / IPD
What
— Guides participants towards basing decisions on objectively discovered and documented facts
How
— Facilitated by someone trained and practiced in CBA
6
CBA VOCABULARY
Factor
— An element of a decision. Differentiates alternatives. DOES NOT INCLUDE $.
Criterion (pl. Criteria)
— A requirement (must or want). The rules that determine how alternatives are judged.
Attribute
— A characteristic, quality or consequence of one alternative as it relates to a factor.
Advantage
— A beneficial difference between the attributes of an alternative and that with the least preferred attribute.
7
CBA VOCABULARY
Factor Trunk capacity
— An element of a decision. Differentiates alternatives. DOES NOT INCLUDE $.
Criterion (pl. Criteria) More is better
— A requirement (must or want). The rules that determine how alternatives are judged.
Attribute 23 cu. ft
— A characteristic, quality or consequence of one alternative as it relates to a factor.
Advantage 49% more cargo space
— A beneficial difference between the attributes of an alternative and that with the least preferred attribute.
8
EXAMPLE: BUYING A CAR
CBA VOCABULARY
9
TABULAR METHOD
1 SCORE 2 SCORE 3 SCORE
Op
tio
n
ALTERNATE ONE 0
Op
tio
n
ALTERNATE TWO 0
Op
tio
n
ALTERNATE THREE 0
1 Factor: Factor 1 Attribute Attribute 1.1 Attribute 1.2 Attribute 1.3
Criteria: Criteria 1Advantage
Advantage 1.10
Advantage 1.20
Advantage 1.30
2 Factor: Factor 2 Attribute Attribute 2.1 Attribute 2.2 Attribute 2.3
Criteria: Criteria 2Advantage
Advantage 2.10
Advantage 2.20
Advantage 2.30
3 Factor: Factor 3 Attribute Attribute 3.1 Attribute 3.2 Attribute 3.3
Criteria: Criteria 3Advantage
Advantage 3.10
Advantage 3.20
Advantage 3.30
CBA VOCABULARY
10
TABULAR METHOD
1 SCORE 2 SCORE 3 SCORE
Op
tio
n
ALTERNATE ONE 0
Op
tio
n
ALTERNATE TWO 0
Op
tio
n
ALTERNATE THREE 0
1 Factor: Factor 1 Attribute Attribute 1.1 Attribute 1.2 Attribute 1.3
Criteria: Criteria 1Advantage
Advantage 1.10
Advantage 1.20
Advantage 1.30
2 Factor: Factor 2 Attribute Attribute 2.1 Attribute 2.2 Attribute 2.3
Criteria: Criteria 2Advantage
Advantage 2.10
Advantage 2.20
Advantage 2.30
3 Factor: Factor 3 Attribute Attribute 3.1 Attribute 3.2 Attribute 3.3
Criteria: Criteria 3Advantage
Advantage 3.10
Advantage 3.20
Advantage 3.30
Alternatives
CBA VOCABULARY
11
TABULAR METHOD
1 SCORE 2 SCORE 3 SCORE
Op
tio
n
ALTERNATE ONE 0
Op
tio
n
ALTERNATE TWO 0
Op
tio
n
ALTERNATE THREE 0
1 Factor: Factor 1 Attribute Attribute 1.1 Attribute 1.2 Attribute 1.3
Criteria: Criteria 1Advantage
Advantage 1.10
Advantage 1.20
Advantage 1.30
2 Factor: Factor 2 Attribute Attribute 2.1 Attribute 2.2 Attribute 2.3
Criteria: Criteria 2Advantage
Advantage 2.10
Advantage 2.20
Advantage 2.30
3 Factor: Factor 3 Attribute Attribute 3.1 Attribute 3.2 Attribute 3.3
Criteria: Criteria 3Advantage
Advantage 3.10
Advantage 3.20
Advantage 3.30
Factors
CBA VOCABULARY
12
TABULAR METHOD
1 SCORE 2 SCORE 3 SCORE
Op
tio
n
ALTERNATE ONE 0
Op
tio
n
ALTERNATE TWO 0
Op
tio
n
ALTERNATE THREE 0
1 Factor: Factor 1 Attribute Attribute 1.1 Attribute 1.2 Attribute 1.3
Criteria: Criteria 1Advantage
Advantage 1.10
Advantage 1.20
Advantage 1.30
2 Factor: Factor 2 Attribute Attribute 2.1 Attribute 2.2 Attribute 2.3
Criteria: Criteria 2Advantage
Advantage 2.10
Advantage 2.20
Advantage 2.30
3 Factor: Factor 3 Attribute Attribute 3.1 Attribute 3.2 Attribute 3.3
Criteria: Criteria 3Advantage
Advantage 3.10
Advantage 3.20
Advantage 3.30
Criteria
CBA VOCABULARY
13
TABULAR METHOD
1 SCORE 2 SCORE 3 SCORE
Op
tio
n
ALTERNATE ONE 0
Op
tio
n
ALTERNATE TWO 0
Op
tio
n
ALTERNATE THREE 0
1 Factor: Factor 1 Attribute Attribute 1.1 Attribute 1.2 Attribute 1.3
Criteria: Criteria 1Advantage
Advantage 1.10
Advantage 1.20
Advantage 1.30
2 Factor: Factor 2 Attribute Attribute 2.1 Attribute 2.2 Attribute 2.3
Criteria: Criteria 2Advantage
Advantage 2.10
Advantage 2.20
Advantage 2.30
3 Factor: Factor 3 Attribute Attribute 3.1 Attribute 3.2 Attribute 3.3
Criteria: Criteria 3Advantage
Advantage 3.10
Advantage 3.20
Advantage 3.30
Attributes
CBA VOCABULARY
14
TABULAR METHOD
1 SCORE 2 SCORE 3 SCORE
Op
tio
n
ALTERNATE ONE 0
Op
tio
n
ALTERNATE TWO 0
Op
tio
n
ALTERNATE THREE 0
1 Factor: Factor 1 Attribute Attribute 1.1 Attribute 1.2 Attribute 1.3
Criteria: Criteria 1Advantage
Advantage 1.10
Advantage 1.20
Advantage 1.30
2 Factor: Factor 2 Attribute Attribute 2.1 Attribute 2.2 Attribute 2.3
Criteria: Criteria 2Advantage
Advantage 2.10
Advantage 2.20
Advantage 2.30
3 Factor: Factor 3 Attribute Attribute 3.1 Attribute 3.2 Attribute 3.3
Criteria: Criteria 3Advantage
Advantage 3.10
Advantage 3.20
Advantage 3.30
Advantages
TABULAR METHOD
15
CBA STEPS1. Define factors
2. Define must have/want to have criteria
3. Formulate range of
alternatives
4. Describe the attributes of
each alternative
5. Decide the advantages of
each alternative
6. Decide the importance of
each advantage
7. Evaluate the cost
TABULAR METHOD
16
SETTING THE STAGE PHASE1. Define factors
2. Define must have/want to have criteria
3. Formulate range of
alternatives
4. Describe the attributes of
each alternative
5. Decide the advantages of
each alternative
6. Decide the importance of
each advantage
7. Evaluate the cost
TABULAR METHOD
17
INNOVATION PHASE1. Define factors
2. Define must have/want to have criteria
3. Formulate range of
alternatives
4. Describe the attributes of
each alternative
5. Decide the advantages of
each alternative
6. Decide the importance of
each advantage
7. Evaluate the cost
TABULAR METHOD
18
DECISION-MAKING PHASE1. Define factors
2. Define must have/want to have criteria
3. Formulate range of
alternatives
4. Describe the attributes of
each alternative
5. Decide the advantages of
each alternative
6. Decide the importance of
each advantage
7. Evaluate the cost
TABULAR METHOD
19
RECONSIDERATION OR IMPLEMENTATION PHASE1. Define factors
2. Define must have/want to have criteria
3. Formulate range of
alternatives
4. Describe the attributes of
each alternative
5. Decide the advantages of
each alternative
6. Decide the importance of
each advantage
7. Evaluate the cost
NORTHWESTERN UNIVERSITY JACOBS CENTER RENOVATIONCBA CASE STUDY
PROGRAM DISTRIBUTION
21
STEP 1 – DEFINE FACTORS
22
SETTING THE STAGE PHASE1. Define factors
2. Define must have/want to have criteria
3. Formulate range of
alternatives
4. Describe the attributes of
each alternative
5. Decide the advantages of
each alternative
6. Decide the importance of
each advantage
7. Evaluate the cost
STEP 1 – DEFINE FACTORS
23
SETTING THE STAGE PHASE
1 SCORE 2 SCORE 3 SCORE
Op
tio
n
ALTERNATIVE ONE 0
Op
tio
n
ALTERNATIVE TWO 0
Op
tio
n
ALTERNATIVE THREE 0
1 Factor: ENERGY USE INTENSITY Attribute Attribute 1.1 Attribute 1.2 Attribute 1.3
Criteria: Criteria 1Advantage
Advantage 1.10
Advantage 1.20
Advantage 1.30
2 Factor: MAINTAINABILITY Attribute Attribute 2.1 Attribute 2.2 Attribute 2.3
Criteria: Criteria 2Advantage
Advantage 2.10
Advantage 2.20
Advantage 2.30
3 Factor: ADAPTABILITY Attribute Attribute 3.1 Attribute 3.2 Attribute 3.3
Criteria: Criteria 3Advantage
Advantage 3.10
Advantage 3.20
Advantage 3.30
STEP 2 – DEFINE CRITERIA
24
SETTING THE STAGE PHASE1. Define factors
2. Define must have/want to have criteria
3. Formulate range of
alternatives
4. Describe the attributes of
each alternative
5. Decide the advantages of
each alternative
6. Decide the importance of
each advantage
7. Evaluate the cost
STEP 2 – DEFINE CRITERIA
25
SETTING THE STAGE PHASE
1 SCORE 2 SCORE 3 SCORE
Op
tio
n
ALTERNATIVE ONE 0
Op
tio
n
ALTERNATIVE TWO 0
Op
tio
n
ALTERNATIVE THREE 0
1 Factor: ENERGY USE INTENSITY Attribute Attribute 1.1 Attribute 1.2 Attribute 1.3
Criteria: Lower is betterAdvantage
Advantage 1.10
Advantage 1.20
Advantage 1.30
2 Factor: MAINTAINABILITY Attribute Attribute 2.1 Attribute 2.2 Attribute 2.3
Criteria: Easier to access/fewer
components is betterAdvantage
Advantage 2.10
Advantage 2.20
Advantage 2.30
3 Factor: ADAPTABILITY Attribute Attribute 3.1 Attribute 3.2 Attribute 3.3
Criteria: More easily adaptable is
betterAdvantage
Advantage 3.10
Advantage 3.20
Advantage 3.30
STEP 3 – FORMULATE ALTERNATIVES
26
INNOVATION PHASE1. Define factors
2. Define must have/want to have criteria
3. Formulate range of
alternatives
4. Describe the attributes of
each alternative
5. Decide the advantages of
each alternative
6. Decide the importance of
each advantage
7. Evaluate the cost
STEP 3 – FORMULATE ALTERNATIVES
27
GROUND AND FIRST FLOORS
Alternative 1 Alternative 3Alternative 2
DOAS central AHUsw/ACBs & radiant
ceiling panels
VAV AHUs with terminal reheat
DOAS central AHUs w/chilled beams
STEP 3 – FORMULATE ALTERNATIVES
28
GROUND AND FIRST FLOORS
Alternative 1 Alternative 3Alternative 2
DOAS central AHUsw/ACBs & radiant
ceiling panels
VAV AHUs with terminal reheat
DOAS central AHUs w/chilled beams
TU w/RHC
STEP 3 – FORMULATE ALTERNATIVES
29
SECOND THROUGH SIXTH FLOORS
Alternative 1
VAV AHUs with terminal reheat
Alternative 3Alternative 2
DOAS central AHUs w/chilled beams
DOAS central AHUsw/chilled terminal units
STEP 3 – FORMULATE ALTERNATIVES
30
SECOND THROUGH SIXTH FLOORS
Alternative 1
VAV AHUs with terminal reheat
Alternative 3Alternative 2
DOAS central AHUs w/chilled beams
DOAS central AHUsw/chilled terminal units
TU w/RHC
TU w/RHC
STEP 3 – FORMULATE ALTERNATIVES
31
INNOVATION PHASE
1 SCORE 2 SCORE 3 SCORE
Op
tio
n
MULTI-ZONE VAV 0
Op
tio
n
DOAS W/ACB 0
Op
tio
n
DOAS CHILLED BOX 0
1 Factor: ENERGY USE INTENSITY Attribute Attribute 1.1 Attribute 1.2 Attribute 1.3
Criteria: Lower is betterAdvantage
Advantage 1.10
Advantage 1.20
Advantage 1.30
2 Factor: MAINTAINABILITY Attribute Attribute 2.1 Attribute 2.2 Attribute 2.3
Criteria: Easier to access/fewer
components is betterAdvantage
Advantage 2.10
Advantage 2.20
Advantage 2.30
3 Factor: ADAPTABILITY Attribute Attribute 3.1 Attribute 3.2 Attribute 3.3
Criteria: More easiliy adaptable is
betterAdvantage
Advantage 3.10
Advantage 3.20
Advantage 3.30
STEP 4 – DESCRIBE ATTRIBUTES OF EACH ALTERNATIVE
32
INNOVATION PHASE1. Define factors
2. Define must have/want to have criteria
3. Formulate range of
alternatives
4. Describe the attributes of
each alternative
5. Decide the advantages of
each alternative
6. Decide the importance of
each advantage
7. Evaluate the cost
VARIABLE AIR VOLUME
33
SYSTEM ZONING PLANS
VARIABLE AIR VOLUME
34
SYSTEM ZONING PLANS
Garden Level 1st Floor 2nd Floor
6th Floor4th Floor 5th Floor
AHU-1
AHU-2
AHU-3
AHU-4
AHU-5
AHU-6
AHU-7
AHU-8
AHU-7
AHU-8
AHU-7
AHU-8
3rd Floor
AHU-5
AHU-6
Total: 200,000 cfm
DEDICATED OUTSIDE AIR SYSTEM (DOAS)
35
SYSTEM ZONING PLANS
DEDICATED OUTSIDE AIR SYSTEM (DOAS)
36
SYSTEM ZONING PLANS
Garden Level 1st Floor 2nd Floor
6th Floor4th Floor 5th Floor
DOAS-1 DOAS-2 DOAS-3
DOAS-4
DOAS-5
DOAS-6
DOAS-3
DOAS-4
DOAS-5
DOAS-6
3rd Floor
DOAS-3
DOAS-4
Total: 68,000 cfm
STEP 4 – DESCRIBE ATTRIBUTES OF EACH ALTERNATIVE
37
INNOVATION PHASE
1 SCORE 2 SCORE 3 SCORE
Op
tio
n
MULTI-ZONE VAV 0
Op
tio
n
DOAS W/ACB 0
Op
tio
n
DOAS CHILLED BOX 0
1 Factor: ENERGY USE INTENSITY Attribute 126.1 88.5 89.1
Criteria: Lower is betterAdvantage
Advantage 1.10
Advantage 1.20
Advantage 1.30
2 Factor: MAINTAINABILITY
Attribute
AHUs and TUs DOAS units w/ERW; TUs;
secondary CHW loop pumps
and branch connections
DOAS units w/ERW; ECM
FPTUs with filter; secondary
CHW loop pumps and TU
connections
Criteria: Easier to access/fewer
components is betterAdvantage
Advantage 2.10
Advantage 2.20
Advantage 2.30
3 Factor: ADAPTABILITY
Attribute
One (1) trade impacted
(sheet metal); recalc OA
using MSE
Two (2) trades impacted
(branch piping and ductwork
to each ACB)
One (1) trade impacted
(sheet metal)
Criteria: More easily adaptable is
betterAdvantage
Advantage 3.10
Advantage 3.20
Advantage 3.30
STEP 4 – DESCRIBE ATTRIBUTES OF EACH ALTERNATIVE
38
INNOVATION PHASE
1 SCORE 2 SCORE 3 SCORE
Op
tio
n
MULTI-ZONE VAV 0
Op
tio
n
DOAS W/ACB 0
Op
tio
n
DOAS CHILLED BOX 0
1 Factor: ENERGY USE INTENSITY Attribute 126.1 88.5 89.1
Criteria: Lower is betterAdvantage
Lea
st -
0Advantage 1.2
0Advantage 1.3
0
2 Factor: MAINTAINABILITY
Attribute
AHUs and TUs DOAS units w/ERW; TUs;
secondary CHW loop pumps
and branch connections
DOAS units w/ERW; ECM
FPTUs with filter; secondary
CHW loop pumps and TU
connections
Criteria: Easier to access/fewer
components is betterAdvantage
Advantage 2.10
Advantage 2.20
Lea
st -
0
3 Factor: ADAPTABILITY
Attribute
One (1) trade impacted
(sheet metal); recalc OA
using MSE
Two (2) trades impacted
(branch piping and ductwork
to each ACB)
One (1) trade impacted
(sheet metal)
Criteria: More easily adaptable is
betterAdvantage
Advantage 3.10
Lea
st -
0Advantage 3.3
0
STEP 5 – DECIDE THE ADVANTAGES
39
DECISION-MAKING PHASE1. Define factors
2. Define must have/want to have criteria
3. Formulate range of
alternatives
4. Describe the attributes of
each alternative
5. Decide the advantages of
each alternative
6. Decide the importance of
each advantage
7. Evaluate the cost
STEP 5 – DECIDE THE ADVANTAGES
40
DECISION-MAKING PHASE
Anchoring to the least preferred attribute, write the advantage
1
1 SCORE 2 SCORE 3 SCORE
Op
tio
n
MULTI-ZONE VAV 0
Op
tio
n
DOAS W/ACB 0
Op
tio
n
DOAS CHILLED BOX 0
1 Factor: ENERGY USE INTENSITY Attribute 126.1 88.5 89.1
Criteria: Lower is betterAdvantage
Lea
st -
030% lower EUI
029% lower EUI
0
2 Factor: MAINTAINABILITY
Attribute
AHUs and TUs DOAS units w/ERW; TUs;
secondary CHW loop pumps
and branch connections
DOAS units w/ERW; ECM
FPTUs with filter; secondary
CHW loop pumps and TU
connections
Criteria: Easier to access/fewer
components is betterAdvantage
Fewest components above
the ceiling; fewer hydronic
components above ceiling
and in MER.
0
Fewer components above the
ceiling0
Lea
st
-
0
3 Factor: ADAPTABILITY
Attribute
One (1) trade impacted
(sheet metal)
Two (2) trades impacted
(branch piping and ductwork
to each ACB)
One (1) trade impacted
(sheet metal)
Criteria: More easily adaptable is
betterAdvantage
Requires one (1) less trade0
Lea
st -
0Requires one (1) less trade
0
STEP 5 – DECIDE THE ADVANTAGES
41
DECISION-MAKING PHASE
Identify the most important advantage in each factor
2
1 SCORE 2 SCORE 3 SCORE
Op
tio
n
MULTI-ZONE VAV 0
Op
tio
n
DOAS W/ACB 0
Op
tio
n
DOAS CHILLED BOX 0
1 Factor: ENERGY USE INTENSITY Attribute 126.1 88.5 89.1
Criteria: Lower is betterAdvantage
Lea
st -
0
Mo
st 30% lower EUI
029% lower EUI
0
2 Factor: MAINTAINABILITY
Attribute
AHUs and TUs DOAS units w/ERW; TUs;
secondary CHW loop pumps
and branch connections
DOAS units w/ERW; ECM
FPTUs with filter; secondary
CHW loop pumps and TU
connections
Criteria: Easier to access/fewer
components is betterAdvantage
Mo
st
Fewest components above
the ceiling; fewer hydronic
components above ceiling
and in MER.
0
Fewer components above the
ceiling0
Lea
st
-
0
3 Factor: ADAPTABILITY
Attribute
One (1) trade impacted
(sheet metal)
Two (2) trades impacted
(branch piping and ductwork
to each ACB)
One (1) trade impacted
(sheet metal)
Criteria: More easily adaptable is
betterAdvantage
Mo
st Requires one (1) less trade
0
Lea
st -
0Requires one (1) less trade
0
STEP 5 – DECIDE THE ADVANTAGES
42
DECISION-MAKING PHASE
Select the Paramount Advantage
3
1 SCORE 2 SCORE 3 SCORE
Op
tio
n
MULTI-ZONE VAV 0
Op
tio
n
DOAS W/ACB 0
Op
tio
n
DOAS CHILLED BOX 0
1 Factor: ENERGY USE INTENSITY Attribute 126.1 88.5 89.1
Criteria: Lower is betterAdvantage
Lea
st -
0
Pa
ra 30% lower EUI0
29% lower EUI0
2 Factor: MAINTAINABILITY
Attribute
AHUs and TUs DOAS units w/ERW; TUs;
secondary CHW loop pumps
and branch connections
DOAS units w/ERW; ECM
FPTUs with filter; secondary
CHW loop pumps and TU
connections
Criteria: Easier to access/fewer
components is betterAdvantage
Mo
st
Fewest components above
the ceiling; fewer hydronic
components above ceiling
and in MER.
0
Fewer components above the
ceiling0
Lea
st
-
0
3 Factor: ADAPTABILITY
Attribute
One (1) trade impacted
(sheet metal)
Two (2) trades impacted
(branch piping and ductwork
to each ACB)
One (1) trade impacted
(sheet metal)
Criteria: More easily adaptable is
betterAdvantage
Mo
st Requires one (1) less trade
0
Lea
st -
0Requires one (1) less trade
0
STEP 6 – DECIDE THE IMPORTANCE OF EACH ADVANTAGE
43
DECISION-MAKING PHASE1. Define factors
2. Define must have/want to have criteria
3. Formulate range of
alternatives
4. Describe the attributes of
each alternative
5. Decide the advantages of
each alternative
6. Decide the importance of
each advantage
7. Evaluate the cost
STEP 6 – DECIDE IMPORTANCE OF EACH ADVANTAGE
44
DECISION-MAKING PHASE
Order Paramount and most important advantages Add importance score to most important advantagesDecide the importance of each remaining advantage
1
23
FACTOR ALTERNATIVE DESIGNATION ADVANTAGE IMPORTANCE
1.2 ENERGY USE INTENSITY DOAS W/ACB Para 30% lower EUI 100
1.3 ENERGY USE INTENSITY DOAS CHILLED BOX - 29% lower EUI 95
2.1 MAINTAINABILITY MULTI-ZONE VAV MostFewest components above clg; fewer hydronic
components above clg & in MER50
2.2 MAINTAINABILITY DOAS W/ACB - Fewer components above the ceiling 20
3.1 ADAPTABILITY MULTI-ZONE VAV Most Requires one (1) less trade 15
3.3 ADAPTABILITY DOAS CHILLED BOX - Requires one (1) less trade 10
1.1 ENERGY USE INTENSITY MULTI-ZONE VAV Least -
2.3 MAINTAINABILITY DOAS CHILLED BOX Least -
3.2 ADAPTABILITY DOAS W/ACB Least -
STEP 6 – DECIDE IMPORTANCE OF EACH ADVANTAGE
45
DECISION-MAKING PHASE
1 SCORE 2 SCORE 3 SCORE
Op
tio
n
MULTI-ZONE VAV 65
Op
tio
n
DOAS W/ACB 120
Op
tio
n
DOAS CHILLED BOX 105
1 Factor: ENERGY USE INTENSITY Attribute 126.1 88.5 89.1
Criteria: Lower is betterAdvantage
Lea
st -
0
Pa
ra 30% lower EUI100
29% lower EUI95
2 Factor: MAINTAINABILITY
Attribute
AHUs and TUs DOAS units w/ERW; TUs;
secondary CHW loop pumps
and branch connections
DOAS units w/ERW; ECM
FPTUs with filter; secondary
CHW loop pumps and TU
connections
Criteria: Easier to access/fewer
components is better Advantage
Mo
st Fewest components above
clg; fewer hydronic
components above clg & in
50
Fewer components above the
ceiling 20
Lea
st -
0
3 Factor: ADAPTABILITY
Attribute
One (1) trade impacted
(sheet metal)
Two (2) trades impacted
(branch piping and ductwork
to each ACB)
One (1) trade impacted
(sheet metal)
Criteria: More easily adaptable is
betterAdvantage
Mo
st Requires one (1) less trade
15
Lea
st -
0Requires one (1) less trade
10
STEP 7 – EVALUATE COST
46
TI VS. FIRST COST
FIRST COST
TOTAL
IMPORTANCE
1 MUTLI-ZONE VAV $ 11,435,553 65
2 DOAS W/ACB $ 11,786,787 120
3 DOAS CHILLED BOX $ 11,368,367 105
STEP 7 – EVALUATE COST
47
TI VS. LIFE-CYCLE COST
LIFE-CYCLE COST
TOTAL
IMPORTANCE
1 MUTLI-ZONE VAV 20,175,945$ 65
2 DOAS W/ACB 18,392,106$ 120
3 DOAS CHILLED BOX 18,436,782$ 105
CONCLUSION
48
Objective 1: Understand what constitutes a sound decision.
Objective 2: Learn the vocabulary of “Choosing by Advantages.”
Objective 3: Learn how to apply CBA to HVAC System Selection.
