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© Trane 200810/11/2014 1 The Latest in High Performance, Hot and Humid Climate, HVAC Systems Art Hallstrom, P.E., ASHRAE Fellow Dan Pollock Trane System.

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Presentation on theme: "© Trane 200810/11/2014 1 The Latest in High Performance, Hot and Humid Climate, HVAC Systems Art Hallstrom, P.E., ASHRAE Fellow Dan Pollock Trane System."— Presentation transcript:

1 © Trane /11/ The Latest in High Performance, Hot and Humid Climate, HVAC Systems Art Hallstrom, P.E., ASHRAE Fellow Dan Pollock Trane System Specialists

2 © Trane /11/20142 ASHRAE’s New HQ Renovation Located in Atlanta, Ga. Hot and Humid Climate A “near net” zero design A living lab to advance the state of the art

3 © Trane /11/20143 Today’s presentation Project Goals – IEQ, EUI, Standards to follow Envelope and Mechanical Systems Design Ventilation System and the DOAS Unit –Energy Wheel –CDQ Wheel –Direct Drive Plenum Fans –DX Coil/Compressors DOAS Unit System Comparisons DOAS Unit Control Questions

4 © Trane /11/20144 ASHRAE HQ Renovation Who – ASHRAE Society, their HQ Where – Atlanta, Ga. NE, near I-85 What – Total building upgrade and energy retrofit. 2 story office building, 30,000 sq ft. Expanded by a new training center Why – Become a living lab to allow researchers to find out how to get to net zero energy design without impacting IAQ When – Construction June 2007-June 2008

5 © Trane /11/20145 Challenges of very low energy use buildings Will it have a Sustainable or Green focus? Sustainable is indoor environment and energy Green includes a whole lot more What metrics to measure? Comfort and health. Also need metrics to evaluate performance. IEQ for comfort, EUI for energy. What EUI energy metric will be used? Site, Design, or Source EUI

6 © Trane /11/20146 IEQ (Indoor Environmental Quality) IEQ is IAQ –Temperature –Humidity –Ventilation –Air Quality Plus –Lighting –Acoustics

7 © Trane /11/20147 EUI – Energy Use Index BTUH/Net conditioned sq ft. – yearly average Has several definitions Site EUI is the power coming into the building. Allows evaluation of existing building performance. Easy to obtain. Design or ASHRAE 90.1 EUI - For new buildings, design only, No plug or process loads. Nearly impossible to measure after the fact. Source EUI – Building power use at the power plant. Generally nation wide plant efficiencies are used to source number. Source EUI often relates to CO2 impact of the building.

8 © Trane /11/20148 EUI varies by building type Design EUI Site EUI

9 © Trane 2008 ASHRAE wanted their HQ building to meet all relevant ASHRAE Standards ASHRAE Standard (energy efficiency) ASHRAE Standard (thermal comfort) ASHRAE Standard (ventilation) ASHRAE Standard (energy in existing buildings) ASHRAE Guideline (commissioning) ASHRAE Guideline (HVAC&R system commissioning) USGBC LEED® Rating System EB Version 2.0 USGBC LEED®-NC Rating System 2.2 Applicable local, state and national building codes ASHRAE Standard 15 (refrigerant safety) ASHRAE Standard 189 (Green) – proposed (portions of) ASHRAE Advanced Energy Design Guide (offices) US EPA Energy Star

10 © Trane /11/ The Building

11 © Trane /11/ ASHRAE HQ Renovation Envelope upgrade – cool white reflective roof membrane New Lighting Low flow fixtures, etc. for 46% reduction in water use PV arrays on roof

12 © Trane /11/ ASHRAE HQ Renovation New Mechanical System: Replaced old VAV reheat rooftop with: –Common dedicated outside air system (DOAS) with Split System Rooftop with energy recovery wheel, series desiccant dehumidification wheel, electrostatic enhanced filters and DX air-cooled R410 multi-stage compressor/condensers –First floor: air-cooled variable refrigerant flow fan coil units with inverter-driven heat pumps –Second floor: 13 ground-source direct expansion heat pumps serviced by 12 wells

13 © Trane /11/ Mechanical System Layout WSHP Filter/vav VRF Filter/vav OA EAOA EA OA

14 © Trane /11/ DOAS Unit

15 © Trane 2008 DOAS Unit Occupied mode

16 © Trane 2008 DOAS Unit Unoccupied mode

17 © Trane /11/ ASHRAE HQ DOAS Unit

18 © Trane /11/ step/30 ton R410 Compressor Split Set up for VAV Outside Air

19 © Trane /11/ Energy Saving System Strategy DOAS Unit will provide Cool, Dry, Filtered Outside Air. 1.Humidity actively controlled to 44 dewpoint at all times by a series desiccant wheel and cooling coil. It can boost water removal when needed. 2.OA CFM delivered to space based on CO2 3.Building pressure controlled with central exhaust fan Room units will do sensible temperature control. 2 and 3 speed fans match sensible load. This control strategy is very simple, easy to manage.

20 © Trane /11/ Before going further, what is the predicted EUI? Old building – Site 76,900 Btuh/Sq ft-year Renovation Site 42,628 Btuh/Sq ft-year 10% larger building– adjusted to same size gives a ~49.9% energy reduction

21 © Trane /11/ The Dedicated Outside Air Unit

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23 © Trane /11/ Energy (Enthalpy) Wheel

24 © Trane /11/ A Energy Wheel ARI 1060 certified Has bypass dampers 78% total effectiveness Rotates at 20 rpm

25 © Trane /11/ Energy Wheel - Modes of Operation

26 © Trane /11/ CDQ Desiccant Wheel When rotating, lowers leaving dewpoint

27 © Trane /11/ CDQ Wheel uses Type 3 Desiccant ability to hold water vapor high relative humidity, % low typical Leaving coil condition typical entering air condition Transfers water from high RH to low RH air

28 © Trane /11/ Medium Size Wheel Series Desiccant Wheel Has bypass dampers Rotates at 8 RPH

29 © Trane 2008 Saves energy 3 ways over cool reheat (2) Reheat Capacity dry-bulb temperature, °F wet-bulb temperature, °F humidity ratio, grains/lb of dry air peak DP OA SA RA (1) Air side savings (3) Colder Coil

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32 © Trane 2008 Controlling the system DOAS takes care of all the latent load, maintains a constant dew point Humidity can be controlled independently of temperature, not humid at part load Control off of space or common return humidity Space units handle sensible energy, little need to add reheat 10/11/201432

33 © Trane 2008 Seven Unique EW/CDQ Control Areas 10/11/201433

34 © Trane /11/ OA Bins – DOAS Performance

35 © Trane /11/ Direct Drive Plenum Fans

36 © Trane /11/ Direct Drive Plenum Fan ‘Rules’ Adjust fan wheel width, diameter and speed for optimal peak efficiency Every fan gets a VFD, not a starter VFD and fan motors can operate above motor synchronous speed (e.g rpm motors can operate safely up to 2700 rpm) Quiet units have a smaller cost premium Standard air handlers can be designed with dual supply fans to reduce unit length New Fan Selection Rules

37 © Trane /11/ Direct Drive Fan Selection at Peak Fan and Motor Efficiency

38 © Trane /11/ BHP Comparison with Standard Fans Supply Fan CFM, 6.22 SP Peak Fan size and typeBHP Wheel Speed hprpm 17B " FC F " AF Housed Y " AF Direct Drive P - 24" AF Belt Drive

39 © Trane /11/ Piezometer Ring Measures fan CFM Built into fan inlet cone No impact on energy No impact on noise Very accurate Order with air handler Inexpensive and Accurate

40 © Trane /11/ Filters – Particulate Only

41 © Trane 2008 Controls Summary Building: DOAS unit controls the building humidity at 44 dewpoint. Room units control sensible temperature and have dry coils. Dry Coils reduces potential for IAQ problems and is more energy efficient. DOAS Unit: Space humidity above dewpoint set point, series wheel is on. Space below dewpoint set point, series wheel is off and coil LAT adjusted to minimize system fighting. Optimized Independent Humidity Control

42 © Trane /11/ Lessons Learned (so far)

43 © Trane 2008 High performance buildings Need a total design approach Arch – Engineer – Owner – CM - Contractors All $ decisions need to be evaluated – envelope, mechanical, green ideas (parking lot dirt) Use total building energy modeling Separate the OA and recirculated air Control humidity from a central point Use airside energy recovery Measure building IEQ and EUI

44 © Trane 2008 Energy Use – Before and After

45 © Trane 2008 Controlling Space Dew Point with lower energy input 10/11/

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75 © Trane 2008 System Comparisons How does the energy wheel and CDQ wheel enhance the cold coil in the ASHRAE HQ DOAS system. –Target: 44 LAT –Atlanta, Ga. Weather –Air cooled dx R410 compressors 1.Cold Coil – Compressor (10.5 EER) 2.Add energy wheel (13 EER, 80% Recovery) 3.Add both wheels (13 EER, 80%, Std CDQ) 10/11/201475

76 © Trane 2008 Cold Coil Approach 10/11/ Compressor, Air Cooled Condenser, Supply Fan

77 © Trane 2008 Cold Coil with Energy Wheel 10/11/ Includes Compressor, Air Cooled Condenser, Supply Fan, Energy Wheel

78 © Trane 2008 Cold Coil with CDQ and Energy Wheel 10/11/ Includes Compressor, Air Cooled Condenser, Supply Fan, Energy Wheel, Series Desiccant Wheel

79 © Trane 2008 Energy savings of new components are significant 10/11/ Old Cool Reheat 13 EER and Energy Wheel Add on 13 EER, Energy and Dehumidification wheels add on CoolingFanCoolingFanCoolingFan Hourly Average KWH 80,613 8,995 54,411 13,334 38,159 17,121 89,607 67,745 55,279 Cooling Energy savings over old Low CFM/Ton Mech Dehumidifier Savings related to Energy Wheel +9% for 24% Savings related to Series Desiccant Wheel +14% for 38% Savings related to 13 EER Compressor 15%

80 © Trane 2008 Summary There are lots of ways to control temperature and humidity. Green buildings need lower shr systems. Control humidity at full AND part load. Look at life costs when design and operating the system Measure building performance on an ongoing basis For sustainable and maintainable operation, keep the design and controls simple. 10/11/201480

81 © Trane /11/ Thank you


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