VARIABLE SPEED TECHNOLOGY AND APPLICATIONS

Jay Eldridge Business Development Manager – Applied Air Systems Spring 2016 AGENDA

• Why Variable Speed • Enabling Technologies - Variable Speed Motors • VRV/VRF Systems • Rooftop Products • Magnetic Bearing Technology

2 WHY VARIABLE SPEED

• Energy Savings •BHP at •BHP at Pump • BHP at Compressor • Meet or exceed ever more challenging energy codes • LEED • Sustainable • Acoustics

3 FULL RANGE ENERGY PERFORMANCE • Full range performance is almost always far more important than full load performance • Best designs take into account reduced load and reduced condensing pressure (dry bulb or wet bulb relief) on systems • Emerging technologies include; – Full range – Permanent magnet synchronous motors – Magnetic bearings – Integrated controls Full Range Full Load

Vs.

4 NEW TECHNOLOGY

• Motors: ECM, Reluctance DC, PMSM • Inverter • High Speed VFD with PMSM

5 BETTER THAN PREMIUM EFFICIENCY

93 92 91 90 89 88 NEMA Efficiency 87 ECM 86 85 84 2357.5 Motor HP

6 RELUCTANCE DIGITALLY COMMUTATED ADVANTAGES OF THE RELUCTANCE DC MOTOR

. Rotating stator field . Electrical field is in the stator not the rotor; no need for brushes Curved . Based on the principles of a Iron direct current motor

. Uses neodymium magnets Neodymium . Benefits from an additional Magnet reluctance torque when loaded . Extreme high performance in low and medium RPM

7 DC COMPRESSOR MOTOR TECHNOLOGY

. Digitally Commutated (DC) Motor . The rotor uses neodymium magnets – 7 times the magnetism of a common magnet . Increased power with decreased electrical requirement

8 COMPRESSOR MOTOR TECHNOLOGY

100 95 18 % 90 30% (%) 85 80 Induction 75 Motor Daikin Inverter Efficiency 70 Motor 65 60 1800 3600 5400 RPM

Core N

S Rare Earth Interior S N N S Magnet Permanent S Magnetic N 9 PMSM MOTOR TECHNOLOGY

PMSM Motor 90

80 SPM Motor Induction Motor ） % 70 Efficiency （

60 Speed （rpm） 0 1800 3600 5400 7200

Core N S Rare Earth S N N S Magnet Ferrite S Magnet N

Surface Permanent Magnetic Interior Permanent10 Magnetic

10 TRADITIONAL NON-INVERTER SYSTEM CONTROLS TEMPERATURE WITH ON-OFF OPERATION AND MINIMAL CAPACITY CONTROL

+V • 60 Hz AC input power drives the compressor

T(sec) • The compressor must operate at full RPM under all load conditions

-V • Very limited efficiency Frequency (Hz) under part load conditions

11 INVERTER DRIVE SYSTEM

• The inverter control converts the +V incoming ac voltage to dc voltage • The inverter then smooths the sine T(sec) wave to insure smooth motor rotation • Reconverts dc to 3 phase ac voltage to the compressor • Vary the frequency applied to the -V Frequency (Hz) compressor motor to modulate the rotational speed which increases or decreases system capacity Inverter +V Circuit

T(sec)

-V Frequency (Hz)

12 INVERTER TECHNOLOGY

+V

T(sec)

-V Frequency (Hz)

+V

T(sec)

-V Frequency (Hz)

13 COMFORTABLE COOLING OPERATION

Temp.

Set temp. Time.

Inverter Non-Inverter: Inverter: Cools a Large Small room quickly temp.difference temp.difference

14 WHAT’SOUTTHERE? COMPRESSOR OVERVIEW

Fixed scroll • On/Off Control Two stage scroll • 2 thru 6 tons

Digital scroll VCC Variable Speed IPM • 3 thru 15 tons • Variable Speed • Load/unload Interior Permanent 20sec time step Magnet Motor

15 2 STAGE SCROLL

Unloads to about 67% Fixed Scroll Sub-Assembly

Modulation Ring And By Pass Seals

Solenoid Coil Locating & Hold Assembly Down Pins

16 DIGITAL SCROLL • Operates as loaded or unloaded • Compressor pulses between conditions –100% loaded and 0% loaded

Unloaded Operation Loaded Operation

17 HOW DIGITAL SCROLLS WORK

• Digital sounds better than “OFF/ON” • 15‐20 second cycle times • Compressor pulses between conditions • 100% loaded and 0% loaded •Head pressure rises quickly when compressor is ON

18 INVERTER SCROLL PERFORMANCE • 60% savings @ 50% load

100% 90% Digital 80% Scroll Variable

Power 70% DPS 60% Speed 50% 40% 30% Compressor 20% % 10% 0% 25% 35% 45% 55% 65% 75% 85% 95% % Cooling Capacity

19 VFD COMPRESSOR AND EFFICIENCY

• VFD compressors take advantage of low lift • Far better efficiency at part load • Minimize temp swings • More efficiency gain with fewer compressors • One is biggest gain • Two is a little less • Four is still less

Source: 50% Advanced Energy Design Guide, K-12, • Lots of low load hours ASHRAE give best payback

20 20 INVERTER BENEFITS

• Capacity control • Very low startup amperage • Quiet compressor startup • No compressor locked rotor amps • Less stress on windings Capacity is adjusted as the load changes to maximize temperature control • Longer run cycles • Better dehumidification in cooling • Fewer start/stop cycles • System pressures increase gradually reducing noise and stress on piping • As nears set point, capacity is automatically “throttled down”

21 ADDITIONAL INVERTER BENEFITS

Electronic control of compressor speed for comfort and energy savings – System capacity modulates up and down • Capacity matches load conditions as they change • Very high comfort levels – High quality heating performance • Compressor increases speed during cold outdoor ambient conditions • Generates higher head pressure, which increases hot gas temperatures and discharge air temperatures • Produces approximately 20% more heat than a standard non-inverter compressor system – Significant increased energy savings during part-load conditions Heat & Cool loads change • During a 12 month period, 75% of the total HVAC run time hours is at less than 70% of full load. (Energy Star building simulation) • Energy efficiency can increase from 40% to 60% during part-load conditions with Inverter driven compressor at low to medium speeds.

22 SYSTEMS - PUTTING IT ALL TOGETHER

–VRF –RTUs +V – T(sec) -V Frequency (Hz)

23 VRF: VARIABLE FLOW

• Inverter Scroll • ECM Fan Motor • Over speed Inverter

24 24 WHAT IS VRF?

Outdoor Unit Main features: – Energy Saving / Inverter technology – Low Noise Levels – Individual control / Zoning Indoor Units – PPD: tenant billing – Long refrigerant piping runs – Wide range of indoor units – Applied systems w/ 20 year life cycle – Small installed footprint

25 VRF - OVERVIEW Water Cooled Air Cooled /Tower Outdoor / Indoor Geothermal

26 VRF SYSTEM COMPONENTS

27 VRF HEAT RECOVERY SYSTEM COMPONENTS

28 INCREASE ENERGY SAVINGS DURING HEAT RECOVERY

Heat Pump Indoor temp : 67oFWB(Cooling) 70oFDB(Heating) Outdoor temp : 95oFWB(Cooling) o 6 Ton Power input 47 FDB(Heating)

Heating Cooling 6 Ton 6.08kW 5.39kW (22519 btu)

Cooling Cooling Heating Heating

Heat recovery

Power input

Simultaneous Approx. cooling & heating 4.8kW 58% Down 12 Ton Cooling Cooling Heating Heating

29 INVERTER CONTROL

(16 Tons) Multi unit VRF capacity control

100%

Smooth control

C a p a c i t y C o n t r o l 7% INV NONNON INV NONNON Low Load High

30 30 COMFORTABLE COOLING OPERATION

Temp.

Set temp. Time .

Inverter Non-Inverter: Inverter: Cools a Large Small room quickly temp.difference temp.difference

31 31 VRF PERFORMANCE Complete SYSTEM IEER range: 16 ~20!

32 VRF: SUMMARY

FEATURES: – Inverter Scroll – ECM Fan Motor – Over speed VFD

BENEFITS: – Great SYSTEM efficiency – Space comfort – Flexibility – Low sound

33 33 SMALL RTUS CAN BE AN APPLIED PRODUCT

• Constant or variable air flow • Single Zone VAV • Cooling only • Cooling with heating – Nat. gas, electric, hot water • Heat pump • Heat pump with auxiliary heating • 100% outdoor air

34 RTU VS VARIABLE SPEED CHILLER PLANTS

Chillers have used VFD for quite a while… All variable speed components in a central plant

Why? For the Lowest Total System Energy Now we have the same type of performance for RTUs

35 EER EQUIVALENT

kW/ton 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2

(I)EER 24 20 17 15 13 12 11 10

Variable speed RTU IEER range ++ Rooftop IEER includes all energy covered by chiller plant, plus.. • Supply fan energy (Coils, filters, etc) • 0.75” Distribution static Rooftops have much lower installed costs

36 APPLICATIONS FOR VARIABLE SPEED RTUS

• Better temp control • DOAS / 100% outside air – Cooling • High efficiency RTU – Heating – LEED – – Stretch standards • Dehumidification • Small space / tight control – Recovered energy reheat • Sound sensitive RTU jobs good for 90.1 • Medical • Less cycling – Medical office buildings • Much quieter – Stand alone urgent care • Applied options • Labs – Built to order • Process / manufacturing – Customizable

37 ADVANTAGES OF INVERTER CONTROL TECHNOLOGY

38 TEMPERATURE CONTROL • Fully modulating Single Zone VAV (SZVAV) • Variable speed compressor controls air temperature • Fan varies speed to match the load 120 110 100 90 80 Discharge Air 70

Temperature 60 Outdoor Air 50 Return Air 40

Time

Actual performance: Convenience store, Dallas TX 39 39 CYCLING EFFECTS

• Reduces latent removal • Re-evaporates coil moisture • As cycling increases, latent cooling goes to zero • As humidity goes up, cycling is more important

40 40 HOW DIGITAL SCROLLS WORK (VARIABLE CAPACITY)

• Digital sounds better than “OFF/ON” • 15-20 second cycle times • Compressor pulses between conditions - 100% loaded and 0% loaded - Head pressure rises quickly when compressor is ON

41 41 LEAVING AIR CONTROL –VARIABLE SPEED VS DIGITAL

OA temp

Room Lvg Air

kW Power

2013- Northwest Energy Efficiency Alliance; NBI: Report #E13-269: Variable Rate Rooftop Unit Test • VFD vs digital scroll compressor (1 min increments) • VFD gives lower kW, stable leaving air temp • 57-75 LAT = 2.7 lbs/min water difference for 4000 CFM

42 DEFINING SINGLE ZONE VAV (SZVAV) • What is Single Zone VAV (SZVAV) – Fan speed controlled by zone temp vs VAV box pressure – Compressor controlled by leaving air temp

• Minimum for requirements for SZVAV in 90.1? – DX: 2-Stg supply fan, Min speed<66% and < 40% fan kW – Chilled Water & other: Min capacity <50% and < 30% fan kW – Hot gas bypass not allowed above min loading (66% for RTU)

• Fully modulating SZVAV will perform better – Fan energy savings (2 speed vs VFD) – Compressor savings (stepped vs VFD) – Tighter control

43 43 ENERGY PLUS MODEL

› Energy Plus has a variable speed DX coils — Up to 10 speed curves vs ambient — Big savings at lower loads › Building models by Pacific Northwest Natl. Labs

› Examples for Rochester — 7000 ft2 retail space – Lights = 8 W/ft2, 62.1 ventilation — 15 ton RTU vs 90.1 baseline — Rigid schedules

44 NERGY LUS E P Compressor Energy (kW) - September, Rochester, NY 12 90 Outdoor Air Temp (F) Variable Speed Single Stage Two Stage 85

10 80

75 8

70

6 65

60

4 55

50 2

45

0 40 09/08 09/08 04:00:00 09/08 06:00:00 09/08 08:00:00 09/08 10:00:00 09/08 12:00:00 09/08 14:00:00 09/08 16:00:00 09/08 18:00:00 09/08 20:00:00 09/08 22:00:00 09/08 24:00:00 09/09 02:00:00 09/09 04:00:00 09/09 06:00:00 09/09 08:00:00 09/09 10:00:00 09/09 12:00:00 09/09 14:00:00 09/09 16:00:00 09/09 18:00:00 09/09 20:00:00 09/09 22:00:00 09/09 24:00:00 09/10 02:00:00 09/10 04:00:00 09/10 06:00:00 09/10 08:00:00 09/10 10:00:00 09/10 12:00:00 09/10 14:00:00 09/10 16:00:00 09/10 18:00:00 09/10 20:00:00 09/10 22:00:00 09/10 24:00:00 09/11 02:00:00 09/11 04:00:00 09/11 06:00:00 09/11 08:00:00 09/11 10:00:00 09/11 12:00:00 09/11 14:00:00 09/11 16:00:00 09/11 18:00:00 09/11 20:00:00 09/11 22:00:00 09/11 24:00:00 09/12 02:00:00

45 ENERGYPLUS Compressor Energy (kW) - July Day in Rochester, NY

16 Variable Speed Two Stage

14

12

10

kW 8

6

4

2

0 8:00:00 10:00:00 12:00:00 14:00:00 16:00:00 18:00:00 20:00:00

46 ENERGYPLUS Compressor Energy (kW) - A week July in Rochester, NY 18 Variable Speed Compressor Two Stage Compressor 16

14

12

10

8

6

4

2

0 07/15 01:00:00 07/15 06:00:00 07/15 11:00:00 07/15 16:00:00 07/15 21:00:00 07/16 02:00:00 07/16 07:00:00 07/16 12:00:00 07/16 17:00:00 07/16 22:00:00 07/17 03:00:00 07/17 08:00:00 07/17 13:00:00 07/17 18:00:00 07/17 23:00:00 07/18 04:00:00 07/18 09:00:00 07/18 14:00:00 07/18 19:00:00 07/18 24:00:00 07/19 05:00:00 07/19 10:00:00 07/19 15:00:00 07/19 20:00:00 07/20 01:00:00 07/20 06:00:00 07/20 11:00:00 07/20 16:00:00 07/20 21:00:00 07/21 02:00:00 07/21 07:00:00 07/21 12:00:00 07/21 17:00:00 07/21 22:00:00

47 WHAT TO WATCH OUT FOR… • Size ranges may not be complete – Offerings from manufacturers may change by capacity • Consider multiple set points vs stepped changes • Units are more complex than off/on – Controls are different than stepped control – Often integrated compressors & heat with dampers and fans – May tie-in to network, BAS, cloud, etc. – Make sure your technicians are trained • Variable speed RTUs cost more than stepped RTUs – Better efficiency and payback – Tighter air temperature control – Applied equipment type sequences

48 VARIABLE SPEED RTU COMPRESSOR SUMMARY

1. Increase part load efficiency 2. Reduce operating costs 3. Increase comfort by running the unit longer 4. Reduce re-evaporation 5. Increase unit capacity 6. Remove more moisture to keep DOAS cost down 7. Keep unit operating with the envelope 8. Monitor refrigerant press./temps to take evasive action

Unit stays on-line

49 CHILLERS

• Permanent Magnet Synchronous Motor (PMSM) • High Speed VFD

50 BASIC MAGNETIC BEARING COMPRESSOR DESIGN

High Speed Permanent Magnet Synchronous Motor

Impeller Front Rear Radial Radial Axial Bearing Bearing Thrust Bearing

51 MAGNETIC BEARING COMPRESSOR

Magnetic bearings VFD and controls and sensors contained in external panel

Inlet Guide Vanes

Suction gas

Single Stage Impeller Permanent magnet synchronous motor (refrigerant-cooled) Discharge Port

52 MOTOR EFFICIENCY 110 Permanent Magnet Synchronous Motor 100

25- 40% 3-5% Efficiency 90 Efficiency Gain Gain Induction Motor

80

70 Efficiency (%) Efficiency

60

50 0 102030405060708090100110 Percentage Speed

53 DRIVE TRAIN COMPARISON –FULL LOAD High Speed Permanent Traditional Variable Magnetic Motor Speed Centrifugal Centrifugal Compressor Compressor Bearing Windage 1.5% 5.0% Motor 2.0% 4.7%

Loss VFD 2.0% 2.4%

Efficiency Efficiency Gear -- 1.0% Resulting Compressor 94.5% 86.9% Efficiency

7.6 Point Efficiency Gain!

54 900 1.2

ENERGY SAVINGS EXAMPLE 800 1 700

600 Fixed Speed ~ $243,287/year 0.8

Cooling Load Profile 500 0.6 400

300 0.4 /kW ton Traditional VFD ~ $164,934/year Operating Hours 200 10% energy 0.2 reduction High Speed VFD w/ Mag Bearing ~ $131,709/year 100

0 0 0 102030405060708090100 Chiller Percent Load

55 OIL REDUCES SYSTEM EFFICIENCY

From ASHRAE Research Project 751-RP, “Experimental Determination of the Effect of Oil on with HCFC-123 and HFC- 134a”,

Conclusions and Recommendations:

“The heat transfer ratio drops steadily with oil concentration and reaches a value of 0.65 [from 1.0 normalized] at an oil concentration of 10%.” 35% heat transfer reduction with 10% oil concentration in refrigerant

56 IMPACT OF OIL ON SUSTAINABLE PERFORMANCE

Positive pressure, oil-free design eliminates the performance degradation due to non-condensables and oil contamination of the refrigerant

Source: The News, 04/15/04, by Jack Sine

57 ADVANTAGES OF VFD AND MAGNETIC BEARING TECHNOLOGY

• Resistant to Power Line Disturbances – Rides through voltage drops – Meets semi conductor industry standard SEMI F47

______

• Regenerative power system keeps bearings powered until shaft stops spinning • Rides through short duration power loss

58 CHILLERS: SUMMARY

PRO: – Part load efficiency – Oil Free Design – Low Maintenance

CON: – First cost typically higher

59 WRAP-UP

• Variable speed compressors have distinct advantages for temperature control and efficiency

• A number of options are available for size and configuration

• Modeling programs, studies and other resources are being developed to estimate actual performance

60 REVIEW QUESTIONS • What is the difference between a digital scroll and an inverter scroll compressor? • What are the advantages of modulating refrigerant flow? • What are the limitations of an AC Induction Motor? • What is more efficient: Surface Permanent Magnetic Motor or an Interior Permanent Magnetic Motor? • What type of rare earth magnet is being used in Interior Permanent Magnetic Motors? • What are the benefits of removing oil from the system? • Why are new products designed for full range?

61 THANK YOU.