HVAC - Maintenance and TechnologiesFederal Utility Partnership Working Group Meeting

Providence, Rhode IslandApril 15, 2010

BY

Ramin Faramarzi, P.E.

Technology Test Centers (TTC)Design and Engineering Services

Southern California Edison (SCE)www.sce.com/rttc

2

Outline

• Introduction to SCE’s TTC• Overview of energy challenges in California (CA) • Role of HVAC in CA’s energy and demand equations• Factors affecting HVAC performance

• Focus on SCE’s research on maintenance faults• Next generation of HVAC equipment• HVAC technologies on SCE’s TTC radar• Black boxes – do they all work?

3

SCE’s Technology Test Centers

• SCE applied research facilities located in Irwindale, CA comprised of 3 test beds:• Refrigeration• HVAC• Lighting

• Coming Soon! - A new ZNE lab

4

Refrigeration Testing

5

HVAC Testing

6

Lighting Testing

7

Future of Energy Efficiency in California

• Climate change initiatives are drivers• California Assembly Bill 32 (AB 32)

• Greenhouse gas (GHG) be reduced to• 1990 levels by 2020• 80% below 1990 level by 2050

• DSM transition to IDSM and renewable generation• By 2020 all new residential buildings and by 2030 all

new construction commercial buildings must be Zero Net Energy (ZNE)

• HVAC systems to be tailored to California’s hot and dry climate

8

California – A Leader in Energy Efficiency

Source: California Energy Commission (2007 Integrated Energy Policy Report, Page 3)

….but its still not enough.

9

ZNE -A Key Step To Achieve GHG GoalsMeeting AB32 Goals

Electric Utilities Contribution

2009 value = 106 MMT CO2e

2050 value = 144 MMT CO2eNo EE Action

2050 value = 90.8 MMT CO2eIOU's Current Action

2050 value = 55 MMT CO2eIOU's EE, C&S, ET

2050 Goal = 19.6 MMT CO2e

1990 value = 93.6 MMT CO2e

2050 value = 6.4 MMT CO2eIOU's EE, C&S, ET, ZNE

0

20

40

60

80

100

120

140

1990 2000 2010 2020 2030 2040 2050

Pow

er G

ener

atio

n to

Ser

ve L

oad

- MM

T C

O2e

Historical Emissions No EE Action IOU's Current ActionIOU's EE, C&S, ET AB32 2050 Goal AB 32 2020 GoalIOU's EE, C&S, ET, ZNE

Data extrapolated from CEC's Integrated Energy Policy Report

10

California and HVAC Facts...

• Peak electric demand nearly ~50,000 MW and is increasing ~1-3.5% annually

• Air conditioning constitutes ~30% of CA’s peak electric load

• Air conditioner compressor consumes the most power• Compressor power consumption increases when the

ambient temperature is high • Overlooked maintenance accounts for ~ 10% of A/C

energy use• Refrigerant leakage from A/C units is equivalent to 8.8

million metric tons of CO2 per year

11

Typical RTU Power Demand(SCE’s test data measured for ARI 115oF ambient test – average of six units)

Evaporator Fan

11.5%

Misc.0.4%

Condenser Fan4.4%

Compressor83.7%

12

Key Parameters Affecting HVAC Performance

• Ambient Conditions• Maintenance• Effectiveness of energy efficiency features

13

• At high ambient temperatures:• Compressor power increases• Cooling capacity decreases

5.0

6.0

7.0

8.0

9.0

10.0

11.0

12.0

13.0

14.0

80 85 90 95 100 105 110 115 120 125 130 135

Ambient Temperature (oF)

EER

Bas

ed o

n R

efrig

erat

ion

Dat

a

(Btu

/hr/w

att)

Mfg A Std Mfg B Std Mfg C StdMfg A Hi Eff Mfg B Hi Eff Mfg C Hi Eff

Effects of High Ambient Temp on EER (SCE’s test results)

14

Effects of Overlooked Maintenance(based on tests conducted at SCE’s TTC)

15

Common HVAC Faults

• Dirty evaporator coils• Dirty air filters• Dirty condenser coils• Improper refrigerant charges• Malfunctioning economizers• Incorrect fan settings• Refrigerant line cloggage

16

Dirty Evaporator Coil Impact on Cooling Capacity

0

10000

20000

30000

40000

50000

60000

70000

Baseline Light Medium

Level of Dirt

Coo

ling

Cap

acity

(Btu

/hr)

• Cooling capacity was degraded by as much as ~40%

17

0.00

1.00

2.00

3.00

4.00

5.00

6.00

Baseline Light Medium

Level of Dirt

Pow

er (k

W)

Total Compressor Evaporator Fan Condenser Fan

Dirty Evaporator Coil Impact on Power

• Compressor power was reduced by as much as ~7%• Evaporator fan power was reduced by as much as ~40%

• Supply CFM was reduced by ~75% due to evaporator cloggage

18

Dirty Evaporator Coil Impact on Efficiency and Supply Air Temperature

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

Baseline Light Medium

Level of Dirt

EER

(Btu

/hr/W

)

57.50

58.00

58.50

59.00

59.50

60.00

60.50

61.00

61.50

Supp

ly A

ir Te

mpe

ratu

re (°

F)

EER Supply Air Temperature

• EER was reduced by as much as ~35%• Supply air temperature was increased by ~2oF

19

Dirty Air Filter Impact on Cooling Capacity

0

10000

20000

30000

40000

50000

60000

70000

Baseline Light Filter Heavy Filter

Level of Dirt

Coo

ling

Cap

acity

(Btu

/hr)

• Cooling capacity was degraded by as much as ~30%

20

Dirty Air Filter Impact on Power

0.00

1.00

2.00

3.00

4.00

5.00

6.00

Baseline Light Filter Heavy Filter

Level of Dirt

Pow

er (k

W)

Total Compressor Evaporator Fan Condenser Fan

• Compressor power was reduced as much as ~4%• Evaporator fan power was reduced by as much as ~35%• Condenser fan power remained constant

21

Dirty Air Filter Impact on Efficiency and Supply Air Temperature

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

Baseline Light Filter Heavy Filter

Level of Dirt

EER

(Btu

/hr/W

)

58.50

58.60

58.70

58.80

58.90

59.00

59.10

59.20

Supp

ly A

ir Te

mpe

ratu

re (°

F)

EER Supply Air Temperature

• EER was reduced by as much as ~20%• SAT was increased ~0.5oF at the light condition, at grater

levels of dirt this data determined to not be valid

22

Dirty Condenser Coil Impact on Cooling Capacity

0

10000

20000

30000

40000

50000

60000

70000

Baseline Very Light Condenser Light Condenser Medium Condenser Heavy Condenser

Level of Dirt

Coo

ling

Cap

acity

(Btu

/hr)

• Cooling capacity was degraded by as much as ~40%• An increase of ~60% in discharge pressure caused a decrease in

refrigeration effect of ~30%, impacting capacity

23

Dirty Condenser Coil Impact on Power

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

Baseline Very Light Condenser Light Condenser Medium Condenser Heavy Condenser

Level of Dirt

Pow

er (k

W)

Total Power Compressor Power Evaporator Fan Power Condenser Fan

• Compressor power was increased by as much as ~70%• Compression ratio increased by ~60%

• Evaporator fan power remained constant• Condenser fan was increased by as much as ~30%

24

Dirty Condenser Coil Impact on Efficiency and Supply Air Temperature

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

Baseline Very Light Condenser Light Condenser Medium Condenser Heavy Condenser

Level of Dirt

EER

(Btu

/hr/W

)

57.00

58.00

59.00

60.00

61.00

62.00

63.00

64.00

65.00

66.00

Supp

ly A

ir Te

mpe

ratu

re (°

F)

EER Supply Air Temperature

• EER was reduced by as much as ~60%• Supply air temp increased by ~5oF

25

Improper Refrigerant Charge Impact on Cooling Capacity

0

10000

20000

30000

40000

50000

60000

70000

-30% -25% -20% -15% -10% -5% 0% 5% 10% 15% 20% 25% 30%

Refrigerant Charge Level

Coo

ling

Cap

acity

(Btu

/hr)BASE CASE

• Undercharged – cooling capacity was reduced by as much as ~20%• Overcharged – there was negligible impact on cooling capacity

26

Improper Refrigerant Charge Impact on Power

0.00

1.00

2.00

3.00

4.00

5.00

6.00

-30% -25% -20% -15% -10% -5% 0% 5% 10% 15% 20% 25% 30%

Refrigerant Charge Level

Pow

er (k

W)

Total Power Compressor Power Evaporator Fan Power Condenser Fan Power

BASE CASE

• Undercharged – total unit power was reduced by as much as ~3%• Overcharged – total unit power was increased by as much as ~5%

27

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

-30% -25% -20% -15% -10% -5% 0% 5% 10% 15% 20% 25% 30%

Refrigerant Charge Level

EER

(Btu

/hr/W

)

58.50

59.00

59.50

60.00

60.50

61.00

61.50

Supp

ly A

ir Te

mpe

ratu

re (°

F)

EER Supply Air Temperature

Improper Refrigerant Charge Impact on Efficiency and Supply Air Temperature

BASE CASE

• Undercharged – reduced efficiency by ~20%, raised SAT by ~1oF• Overcharged – negligible impact on both efficiency and SAT

28

Next Generation of HVAC Technologies

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Characteristics of Next Generation HVAC Equipment

• High efficiency at peak design and under part load • Climatic region sensitive design• Robust integration capabilities with:

• Building energy systems,• Building automation• Smart meter/grid

• Intelligent and demand response ready• Environmentally friendly refrigerants• Compliant with indoor air quality and human comfort• Reliable• Cost effective

30

Next Generation of A/C Units Features

• Efficient• Low temperature lift heat exchangers• Compressor-less: indirect/direct cooling systems• Desiccant dehumidification• Variable speed fan and compressor: match capacity and load• Efficient compressor and fan motors• Precise metering device: electronic expansion valve (EXV)• Hybrid Cooling: adiabatic + direct expansion (DX)• Indirect or direct evaporatively cooled condensers• Heat recovery

31

Next Generation of A/C Units Features (cont’d)

• Intelligent• 2-way connectivity• Smart user interface and energy advisory• On-board fault detection and diagnostic• Direct digital control

• Indoor Air Quality• Economizer integrated with Demand Controlled Ventilation

• Low GWP Refrigerant• Natural refrigerants

• Hydrocarbons• CO2

32

Technologies on SCE’s Radar Screen

33

On-Board Fault Detection and Diagnostics• Detect failed:

• Compressor• Evaporator and condenser fan motors• Evaporator fan belt

• Detect degradation/maintenance faults:• Dirty air filter• Dirty evaporator and condenser coils• Dirty refrigerant filter• Failed relief damper• Air in refrigeration loop• Restriction in refrigeration loop

• Detect economizer damper operation• Detect air temperature differential across evaporator• Detect low/high refrigerant charge levels• Detect faulty and failed sensors

34

Advanced Direct Evaporative Cooler

• Residential and light commercial~ 4 Ton

• Suitable for hot/dry climates• Electronically commutated

motor (ECM)• Efficient centrifugal fan• Long life ChillcelTM pads• Automatic motor speed adjustment:

• Accommodate different ducting systems and back pressures

• Electronic water quality management system:• Before impurities build-up inside the cooler, they are automatically

detected and replaced with clean water

• Quiet operation

35

Advanced Indirect/Direct Evaporative Cooler

• Suitable for hot/dry climates• > 40 SEER• Counter-flow heat exchanger

between:• Indirect: cool RA/hot OSA• Direct: Warm/dry OSA cools • ECM fan motors

• Compared to vapor compression A/C, a PIER Tech Brief says:• ~90% - energy savings• ~80% - demand savings

36

Evaporatively Cooled DX Split System• Residential and light commercial• Suitable for hot/dry climates• High efficiency (EER = 14.5)• ~ 40% downsized scroll compressor• ECM condenser fan motor• PSC indoor blower fan• Operates at lower head pressures than a

traditional air-cooled condenser• Quiet operation• SCE’s Test Results-compared to an air-

cooled unit, at 95oF (AHRI) showed:• Power reduction of ~50%• EER improvement of 3.5 Btu/hr/watts

37

Multi-Zone VRF A/C System• Claimed system efficiency > 21 SEER• One condensing unit can serve up to 16 zones• Variable refrigerant flow zoning system • Low fan energy• Inverter controlled high efficiency blower fan• Inverter controlled compressor optimizes part-load

efficiency by matching capacity with cooling load• Improved human comfort thru tight individual zone

temperature control • Conditions only the occupied spaces• Zonal heat recovery• Ducted or ductless indoor units• Manage up to 2,000 indoor units from a single PC• Energy recovery ventilators (ERV)• Integration with building EMS

Indoor Unit

Outdoor Unit

38

New Premium Efficiency Rooftop Units• Energy Star & CEE Tier II qualified

• Up to 17 SEER and 14.3 EER• Multiple evenly sized high-efficiency scroll compressors• Economizer• Large heat exchanger• VSD supply fan• ECM fan motors• Intelligent direct digital controls

39

Hybrid Packaged Rooftop Unit• Premium efficiency 5-ton packaged rooftop AC for residential/small commercial• Up to 58% peak demand and 80% energy savings compared to 2010 DOE

standards• Winner of UC Davis Western Cooling Challenge• Indirect evaporative cooling + DX cooling • Evaporatively pre-cooled condenser • ECM fan motors

40

CO2 Heat Pump• Refrigerant, CO2: GWP = 1 ; ODP = 0• Dual stage intercooler (DSI) circuit• High efficiency heat exchangers • EXV• Hi efficiency compressor• Hi efficiency fan motors• COP - compared to R-22

• Cooling: barely compatible• Heating: up to 14% higher

41

Radiant Cooling• Uses chilled water as cooling fluid• High EER• No fan power/energy• Higher energy and demand savings under low

cooling load conditions• Cooling tower economizer mode with no chiller running

42

Not Every Black Box Works

43

Black Box 1Annular Refrigerant Flow Device (ARFD)

What is it?• A 2-way box between TXV and

evaporator• Installation and set up requires over

hauling more than 10 areas of the unit first (e.g., superheat, over sized TXV, etc.)

Claims?• Reduces energy usage by at least 15%• Extends equipment life• Reduces maintenance costs• Maintains consistent temperatures

44

Black Box 1 – ARFD

How does it work?• It enhances heat transfer efficiency by changing the quality of

refrigerant in evaporator (close to all liquid phase)

Applications?• Commercial refrigeration and air conditioning systems

45

Black Box 1 (ARFD) – Laboratory Test Results

• Baseline – 5-ton RTU, SEER 14 and EER 12.5, nonadjustable TXV set to 10-15oF superheat

• With ARFD, EER of the unit was decreased for all AHRI test conditions

58.4

8.4 5.1

51.3

63.1

45.9

4.97.80

10

20

30

40

50

60

70

EER(Btu/hr/watts)

Comp. Power (kW)

Net Cooling Cap. (kBtu/hr)

Supply Air Temp.(°F)

115oF Steady State Test Condition

EER,

Pow

er, C

apac

ity, a

nd

Supp

ly A

ir Te

mpe

ratu

re

Baseline

ARFD

%∆ = -5%%∆ = -8%

%∆ = -12%

%∆ = 7%

46

Black Box 2 – Refrigeration System Optimizer

What is it?• An electrical device to optimize the compressor run time• Installed on systems with oversized compressor capacity

Claim?• Reduces energy usage of oversized compressor by at least 10%

BlackBox 2

47

Black Box 2 (Refrigeration System Optimizer)

How does it work?• It improves system performance by real-time “load-demand”

analysis and control

Applications?• Commercial refrigeration and air conditioning systems• Residential refrigeration and air conditioning systems

48

Black Box 2 (Refrigeration System Optimizer)Preliminary Laboratory Test Results

20.722.1

19.318.0

20.922.1

19.418.2

2.40 2.482.242.16 2.42 2.522.252.180

4

8

12

16

20

24

No Over Sizing 10% Over Sizing 20% Oversizing 25% Over Sizing

Test Scenarios

Com

pres

sor R

un T

ime

(hou

rs)

and

Pow

er (k

W)

Run Time (Baseline) Run Time (Measure) Power (Baseline) Power (Measure)

• For all scenarios, maximum product temperature was below 40oF

49

Appendix

50

Dirty Evaporator Coil

CLEAN COIL

DIRTY COIL

51

Dirty Air Filter

CLEAN FILTER DIRTY FILTER

52

Dirty Condenser Coil

CLEAN COIL

DIRTY COILBlocking Material

53

Improper Refrigerant Charge

54

Nanofluids

• Nanofluids: new class of advanced heat-transfer fluids engineered to disperse nanoparticles smaller than 100 nm (nanometer) in conventional refrigerants• Improve heat transfer effectiveness of evaporator and

condenser coils• No cloggage due to extremely small nano structure

• Technology still in the fundamental research stage