Arthur Rosenfeld, California Energy CommissionGregory Rosenquist, Lawrence Berkeley National Laboratory

C. Keith Rice, Oak Ridge National Laboratory

ARI Spring Product Section MeetingReston, VA. April 18, 2005, modified on 4-20

ARosenfe@Energy.State.CA.US

Economic Evaluation ofEconomic Evaluation ofResidential Air Conditioner Designs Residential Air Conditioner Designs

for Hot and Dry Climatesfor Hot and Dry Climates

2

Total Electricity Use, per capita, 1960 - 2001

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

19

60

19

62

19

64

19

66

19

68

19

70

19

72

19

74

19

76

19

78

19

80

19

82

19

84

19

86

19

88

19

90

19

92

19

94

19

96

19

98

20

00

KW

h

12,000

8,000

7,000

California

U.S.

kWh

Californians have avoided annually $1500/family

California has lower per capita electricity California has lower per capita electricity use than the rest of the countryuse than the rest of the country

3

Cal ISO Daily Peak LoadsJanuary 1, 2000 - December 31, 2000

20

25

30

35

40

45

50

Jan-0

0

Feb-0

0

Mar

-00

Apr-00

May

-00

Jun-0

0

Jul-0

0

Aug-00

Sep-0

0

Oct-0

0

Nov-00

Dec-0

0

GW

Peak Day August 16 - 43.5 GW

Commercial AC

Residential AC

Daily peak loads in California are highest Daily peak loads in California are highest during the summerduring the summer

4

DOE has funded research at ORNL to DOE has funded research at ORNL to develop A/C designs for hot/dry climatesdevelop A/C designs for hot/dry climates

• Several Hot/Dry designs were developed by ORNL relative to a conventional baseline design

• Three Hot/Dry designs were adapted for economic evaluation— Baseline design: 13 SEER, R-410A

— Hot/Dry designs• Design 1: 1.4X Evap HX surface area• Design 2: 1.4X Evap HX surface area; ECM Blower Motor• Design 3: 1.4X Evap HX surface area; ECM Blower Motor; Rated Ducts

System Evaporator Compressor Ducts

Design SEERHot/Dry EER

Out: 115°FIn: 80°F/62°F

Face AreaSq.ft.

FlowCFM

Fan Power115°F; 80/62°F

Watts

Evap TempOut: 95°F

In: 80°F/67°F

Percent ofBaseline

DisplacementType / Ext. Static

Inches H2O

Baseline 13.1 7.5 5.0 1200 355 48°F - Typical / 0.5"@1200 CFM

Design 1 13.8 8.0 7.2 1200 330 52°F 94% Typical / 0.5"@1200 CFM

Design 2 14.6 8.4 7.2 1200 265 52°F 91% Typical / 0.5"@1200 CFM

Design 3 15.4 9.2 7.2 1500 250 55°F 84% Rated / 0.15" fixed

5

Designs evaluated at multiple temperatures Designs evaluated at multiple temperatures for purposes of modeling in a typical housefor purposes of modeling in a typical house• Baseline and three Hot/Dry designs were simulated with the ORNL

Heat Pump Design Model, Mark VI, at four sets of outdoor dry bulb/indoor wet bulb temperature conditions — More efficient designs maintain their efficiency advantage regardless of

temperature conditions— Compressor downsized to match baseline capacity-- hot/dry design condition

7

8

9

10

11

12

13

14

15

16

17

85/62 85/67 85/72 95/62 95/67 95/72 105/62 105/67 105/72 115/62 115/67 115/72

Outdoor Dry Bulb / Indoor Wet Bulb Temperature

EE

R

Design 3

Design 2

Design 1

Base

Indoor Dry Bulb Temp = 80'F

Very close to EERB

(SEER) rating point

6

Prototypical house chosen for two hot/dry Prototypical house chosen for two hot/dry locations: Fresno, CA and Phoenix, AZlocations: Fresno, CA and Phoenix, AZ

• California prototypical house for Fresno

• Fresno house modeled in Phoenix (only weather changed)

• Both locations modeled with DOE-2 — Square footage: 2258 sq.ft.

— Number of floors: 2

— Floor type: Slab-on-grade

— Exterior wall• Area: 1584 sq.ft.

• Insulation: R-13

— Ceiling insulation: R-30

— Windows• Area: 251 sq.ft.

• Window-to-Wall Ratio: 16%

• R-value: R-1.2 (double-glazing)

7

Designs yield both annual energy and peak Designs yield both annual energy and peak demand savings in Fresnodemand savings in Fresno

Fresno: Annual Energy Use

76397413 7188

6832

0

1000

2000

3000

4000

5000

6000

7000

8000

Base Design 1 Design 2 Design 3

An

nu

al E

ne

rgy

Us

e (

kW

h/y

r)

Fresno: Peak Day in July

0

1

2

3

4

5

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hour

Lo

ad

(k

W)

Base

Design 1

Design 2

Design 3

8

Designs yield both annual energy and peak Designs yield both annual energy and peak demand savings in Phoenix demand savings in Phoenix

Phoenix: Annual Energy Use

1234211835

1135710579

0

2000

4000

6000

8000

10000

12000

14000

Base Design 1 Design 2 Design 3

An

nu

al E

ne

rgy

Us

e (

kW

h/y

r)

Phoenix: Peak Day in August

0

1

2

3

4

5

6

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hour

Lo

ad

(k

W)

Base

Design 1

Design 2

Design 3

9

CEC-PIER Hot-Dry a/c Proof of Concept ProjectCEC-PIER Hot-Dry a/c Proof of Concept Project

• Proctor Engineering et al. have modified Keith Rice’s Designs and built two early prototypes optimized for California a/c loads, one 3-ton residential split system, one 5-ton commercial package unit. Actual measurements to date support the calculations provided in earlier slides

• See http://www.hdac-des-pier.com/project.html

10

Residential electric utility tariffs used to Residential electric utility tariffs used to calculate billscalculate bills

• Phoenix: Arizona Public Service Co.

• Residential Service E-12 (Effective July 1, 2003)

— Monthly Summer Charges• 0 to 400 kWh: 7.38 ¢/kWh

• 400 to 800 kWh: 10.28 ¢/kWh

• Remaining kWh: 11.99 ¢/kWh

— Monthly Winter Charges• All kWh: 7.39 ¢/kWh

— Fixed Charges• Basic Service Charge: $7.50

• Fresno: Pacific Gas & Electric Co.

• Schedule E-1 – Residential Service (Zone R) (Effective March 1, 2004)

— Monthly Summer Charges• 0 to 534 kWh: 12.59 ¢/kWh• 534 to 694 kWh: 14.32 ¢/kWh• 694 to 1068 kWh: 18.15 ¢/kWh• 1068 to 1602 kWh: 21.43 ¢/kWh• Remaining kWh: 21.43 ¢/kWh

— Monthly Winter Charges• 0 to 387 kWh: 12.59 ¢/kWh• 387 to 503 kWh: 14.32 ¢/kWh• 503 to 774 kWh: 18.15 ¢/kWh• 774 to 1161 kWh: 21.43 ¢/kWh• Remaining kWh: 21.43 ¢/kWh

— Fixed Charges• Monthly Charge: $5.00

11

Time dependent valuation (TDV) prices are Time dependent valuation (TDV) prices are also used to calculate billsalso used to calculate bills• TDV prices are incorporated into California appliance standards

(Title 20) and building standards (Title 24)• TDV prices, or avoided costs, are independent of the idiosyncrasies

of utility tariffs• TDV prices incent efficient air conditioners

TDV: Climate Zone 13 (Fresno), August 6

0.0

10.0

20.0

30.0

40.0

50.0

60.0

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hour

TD

V (

ce

nts

/kW

h)

12

Time dependent valuation (TDV) prices Time dependent valuation (TDV) prices vary over the yearvary over the year

• Although TDV prices in some hours exceed 50 ¢/kWh, annual average TDV price equals 15 ¢/kWh

TDV: Climate Zone 13 (Fresno), Annual

0

10

20

30

40

50

60

0 876 1752 2628 3504 4380 5256 6132 7008 7884 8760

Hour

TD

V (

cen

ts/k

Wh

)

13

Fresno A/C energy use can now be Fresno A/C energy use can now be expressed as utility bills – PG&E and TDV expressed as utility bills – PG&E and TDV

Fresno: Annual Utility Bill

$967 $928 $890$832

$1,506$1,456

$1,407$1,327

$0

$200

$400

$600

$800

$1,000

$1,200

$1,400

$1,600

Base Design 1 Design 2 Design 3

An

nu

al B

illResidential

TDV

14

Phoenix A/C energy use can now be Phoenix A/C energy use can now be expressed as utility bills – APSC and TDVexpressed as utility bills – APSC and TDV

Phoenix: Annual Utility Bill

$1,280 $1,221 $1,167$1,079

$2,401$2,297

$2,199$2,044

$0

$500

$1,000

$1,500

$2,000

$2,500

Base Design 1 Design 2 Design 3

An

nu

al B

ill

Residential

TDV

15

Consumer price of more efficient designs Consumer price of more efficient designs increase with efficiencyincrease with efficiency

Manufacturer Cost Δ Consumer Price

CompressorEvap Coil

Evap Motor

Total Δ Cost Δ Price Δ Ducts Δ Total

Baseline $168 $113 $61 $342 - - - -

Design 1 $158 $172 $61 $391 $49 $101 - $101

Design 2 $153 $172 $185 $510 $168 $348 - $348

Design 3 $141 $172 $185 $497 $155 $322 $500 $822

• Manufacturer cost estimates from 2001 DOE Technical Support Document

16

Cost-effectiveness of designs based upon Cost-effectiveness of designs based upon LCC savings and paybackLCC savings and payback

• Life-cycle cost (LCC) is the sum of the total installed cost plus the present value of the lifetime operating cost savings

— For residential tariff calculations, present value of future operating cost savings calculated with a 5.6% real discount rate

— Equipment lifetime set to 18.4 years

— Future electricity price trends based upon DOE-EIA’s 2004 Annual Energy Outlook

— Both the discount rate and lifetime are taken from DOE’s central air conditioner rulemaking analysis

• Payback period is the increase in total installed cost divided by the annual operating cost savings

17

All designs provide both LCC savings and All designs provide both LCC savings and short payback periods in Fresnoshort payback periods in Fresno

Fresno: Life-Cycle Cost

$14,021 $13,695 $13,708 $13,548

$21,091 $20,573 $20,213 $19,708

$0

$5,000

$10,000

$15,000

$20,000

$25,000

Base Design 1 Design 2 Design 3

Lif

e-C

yc

le C

os

t

Residential

TDV

Fresno: Payback Periods

2.6

5.8

7.0

2.0

3.5

4.6

0

1

2

3

4

5

6

7

8

Design 1 Design 2 Design 3

Pa

yb

ac

k P

eri

od

(y

ea

rs)

Residential

TDV

18

All designs provide both better LCC savings All designs provide both better LCC savings and shorter payback periods in Phoenixand shorter payback periods in Phoenix

Phoenix: Life-Cycle Cost

$17,436 $16,902 $16,740 $16,251

$32,096$30,917 $29,955

$28,527

$0

$5,000

$10,000

$15,000

$20,000

$25,000

$30,000

$35,000

Base Design 1 Design 2 Design 3

Lif

e-C

yc

le C

os

t

Residential

TDV

Phoenix: Payback Periods

1.8

3.7

4.5

1.0

1.7

2.3

0

1

2

3

4

5

Design 1 Design 2 Design 3P

ay

ba

ck

Pe

rio

d (

ye

ars

)

Residential

TDV

19

Cost of Conserved Energy (CEE) can also Cost of Conserved Energy (CEE) can also be used to evaluate designsbe used to evaluate designs

yearper

AC

kWh

CRRCCE

$

CEE = Cost of Conserved EnergyΔ$AC = Consumer price increase due to hot/dry

AC designCRR = Capital recovery rate; set at 10% per

yearΔkWhper year = Annual energy savings due to hot/dry

AC designTDV (CZ 13, Aug 6) comparison to Design CCEs

0.0

10.0

20.0

30.0

40.0

50.0

60.0

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hour

TD

V a

nd

CC

E(c

en

ts/k

Wh

)

TDV

CCE Design 3

CCE Design 2

CCE Design 1

20

Summary of Analysis Summary of Analysis

• All three Hot/Dry A/C designs developed by ORNL provide LCC savings and relatively short payback periods— LCC savings range from:

• ~$300 to ~$1200 based on residential electric utility tariffs

• ~$500 to ~$3500 based on TDV prices

— Payback periods range from 2 to 7 years

— LCC savings and payback periods are relative to a 13 SEER baseline design

• To exploit full savings potential:— Manufacturers need to offer equipment designed for Hot/Dry

climates

— California needs to revise building standards to ensure good ducts