© 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.

© Trane 2008 10/11/20143 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

© Trane 2008 10/11/20144 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

© Trane 2008 10/11/20145 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

© Trane 2008 10/11/20147 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.

© Trane 2008 ASHRAE wanted their HQ building to meet all relevant ASHRAE Standards ASHRAE Standard 90.1-2004 (energy efficiency) ASHRAE Standard 55-2004 (thermal comfort) ASHRAE Standard 62.1-2004 (ventilation) ASHRAE Standard 100-2006 (energy in existing buildings) ASHRAE Guideline 0-2005 (commissioning) ASHRAE Guideline 1-2006 (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

© Trane 2008 10/11/201412 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

© Trane 2008 10/11/201419 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.

© Trane 2008 10/11/201420 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

© Trane 2008 10/11/201427 CDQ Wheel uses Type 3 Desiccant ability to hold water vapor high relative humidity, % low 060100402080 typical Leaving coil condition typical entering air condition Transfers water from high RH to low RH air

© Trane 2008 Saves energy 3 ways over cool reheat (2) Reheat Capacity 11030405060708010090 dry-bulb temperature, °F 80 70 50 40 30 wet-bulb temperature, °F 60 180 160 140 120 100 80 60 40 20 humidity ratio, grains/lb of dry air peak DP OA SA RA (1) Air side savings (3) Colder Coil

10/11/2014 30

© 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

© Trane 2008 10/11/201436 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. 1800 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

© Trane 2008 10/11/201438 BHP Comparison with Standard Fans Supply Fan - 6513 CFM, 6.22 SP Peak Fan size and typeBHP Wheel Speed hprpm 17B - 18.25" FC12.481465 F17 - 18" AF Housed10.572346 Y17 - 22.25" AF Direct Drive10.022027 17P - 24" AF Belt Drive10.781940

© 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

© 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

© 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

© Trane 2008 Energy savings of new components are significant 10/11/201479 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%

© 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

© 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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© 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:

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