maximize displacement ventilation Opportunities

DESIGN STRATEGIES In Seattle, the Amazon Headquarters building, features an open air atrium that provides natural ventilation throughout the facility. DESIGN STRATEGIES

VENTILATION FOR OPTIMUM INDOOR AIR QUALITY

DISPLACEMENT VENTILATION A passive approach to introducing fresh, cool air to maintain comfort and air quality. In the right environment, displacement ventilation can prove to be a cost- effective, sustainable solution.

Glumac continues to apply established MEP technologies (0.3 to 0.4m), and diffusers mounted on either the wall, like displacement ventilation in new and creative ways. In a floor, or in the corners. In open office environments, these commercial or institutional setting, these systems supply a systems utilize raised access flooring to distribute air and “cool pool” of air in a space at floor level. Through natural facilitate cabling and power changes for areas with high buoyancy, the air – attracted naturally to heat sources turnover rates. Displacement ventilation also performs well such as people, computers, and lighting – warms up and in semi-conditioned spaces that feature high ceilings, such rises gently while maintaining comfortable conditions for as building lobbies and atriums. occupants. Typical system components include the air Auditoriums represent another successful application handling unit, environmental air space of 12 to 16 inches for Glumac designers. Here, theatrical lighting creates the DESIGN STRATEGIES PROCESS/TOOLS the heatfrom theatrical lighting,etc. 32.2ºC attheceiling, where it is then extracted along with with temperatures increasing to 85ºFto 90ºF/29.4ºCto 76ºF/23.3ºC to 24.4ºC.Thewarmairthen migrates upward remain atdesired temperatures, approximately 74ºFto a space. For example: occupied zones, at six feet andbelow, 63ºF and65ºF/17.2ºC18.3ºC–stratifies temperatures in auditorium. Instead, supplying air at the floor level – between so temperatures vary widely from seatto seatwithinan traditional diffusers alsodonotcreate adequate air flow, generated bytheaudience duringaperformance. heat gainfrom multiple lightfixtures inadditionto theheat systems produce additionalcooling to counter theeffects of biggest space load, requiring thatconventional overhead air 7:00 a.m.andp.m.Monday through Friday). the year fall below 65°F/18.3°C(with3,952hours between 7:00 p.m.Mondaythrough Friday). Inaddition, 7,671hours of those hours beinggeneral work time,between 7:00 a.m.and 4,165 hours oftheyear fall below 55°F/12.8°C(with980of energy savings. In San Francisco’s climate, for example, return air. This“free cooling” approach can lead to significant to heatorcool spaces andequipmentwhile exhausting the into acentral airhandlingsystem, bringinmore outsideair at 52ºFto 55ºF/11.1ºCto 12.8ºC. Thesedevices, integrated to 18.3ºC–versus aconventional system thatdelivers air operating many more hours ayear at60ºFto 65ºF/15.6ºC economizer cycle (theabilityto cool withoutsideair), ventilation systems alsotake fuller advantage ofabuilding’s AIR SIDEADVANTAGES heat from people andequipmentasitrisesto theceiling. example) bythedisplacement ventilation system, pickingup air isdelivered across thespace (lobbies andcorridors, for tied into the building’s duct system. In each case, low velocity corners, asfree-standing units,ormounted into wallsand the useofvertical displacement diffusers –eitherplaced in increase orreduce theamountofcooling airintheir space. contains anadjustable airflow control soevery occupant may space, others wantitwarmer;eachfloor diffusertherefore temperature control. While some occupants prefer acooler energy consumption andgreater flexibility for individual Additional benefitsofthesesystems includereduced relocated simply byunscrewing andmoving floor tiles. ductwork schemes,electrical outlets andairoutlets are layouts inopenfloor plans.Incontrast to conventional air provides anaffordable solutionfor reconfiguring office ENVIRONMENT UNDER FLOOR AIRFOR THEOFFICE Though designedto minimizeacoustic levels, most Glumac reviews several criteria before recommending Due to highersupply temperatures, displacement On projects withoutraised floors, Glumacpromotes The use of raised access flooring to distribute underfloor renovated historic warehouse buildinginP utilizes displacement ventilation, most notably central witha worldwide leader inwindturbinemanufacturer, islocated in a The NorthAmerican headquarters facility for V atrium thathelpscondition theoffice spaces. ortland, Oregon, and estas, a DESIGN STRATEGIES

8. HV 7. skylightbuildingrelief withfan assist 6. atriumwithstack ventilation 5. floor diffusers 4. underfloor airdistribution 3. raised access floor 2. airhandlers 1. outsideairintake A C return wallgrillwithsoundtrap 2 2 2 1 8 5 BEFORE: VESTAS HEADQUARTES 3 4 7 DISPLA 6 confirmed this. floors. Glumac’s computational fluiddynamic(CFD)models heat from theskylightandcreating excessive heatfor upper return airinlets were placed too close to theperimeter, drawing systems. IntheoriginalHV for Vestas, aleading manufacturer ofhigh-tech windpower in theLEEDPlatinumrenovation ofaP Simple Physics:Underfloor airdistribution figures prominently CEMENT A C layout, designers discovered

VENTILATION ortland landmark

temperature in fahrenheit 100 67 69 71 73 77 79 81 83 85 87 89 91 93 95 97 HEADQUARTES AFTER: VESTAS DESIGN STRATEGIES

8. HV 7. skylightbuildingrelief withfan assist 6. atriumwithstack ventilation 5. floor diffusers 4. underfloor airdistribution 3. raised access floor 2. airhandlers 1. outsideairintake 8 A C return wallgrillwithsoundtrap 1 2 2 2 5 HEADQUARTES 3 AFTER: VESTAS 4 7 DISPLA 6 throughout interior spaces. changes would improve airdistribution attarget temperatures buildup problem. Again,CFDmodelingconfirmed these moved return airinlets close to theskylightto solve theheat CFD Solution:InGlumac’s revised HV CEMENT

VENTILATION A C schematic,designers

temperature in fahrenheit 100 67 69 71 73 77 79 81 83 85 87 89 91 93 95 97 DESIGN STRATEGIES Seattl overhead systems provide supplemental heatingorcooling. supports the base (or constant) loads of the space, while the ceiling level. Withthiscombination, displacement ventilation well intandem withchilled beams/overhead radiant atthe air system. climates without a return air bypass or a dedicated outside 55°F/12.8ºC, sothistechnology isnot well suited for humid humidity): To dehumidifyaspace requires cooling theairto Location (proximity to outdoorairtemperatures and to ankle level andcreate anuncomfortable environment. otherwise, lower temperatures maytend to draft down to condition only occupied spaces (upto sixfeet/1.8m); displacement diffusers enters ataminimumof63°F/17.2ºC 55°F/12.8ºC to condition entire spaces, discharge airvia conventional systems typically introduce air at a cooler for acompletely different typeofdesignthinking.Where weigh thefollowing points: p.m., orare they operate late –oreven 24/7?Designers also conference rooms with program areas openfrom 9a.m.to 5 rate? How willspace beused:doesthebuildingincludelarge project feature anopenoffice, withanexpected highchurn a displacement ventilation scheme.For example, doesthe e |PortlandCorvallis |RenoSacramentoSanFrancisco |SiliconValleyLasVegas LosAngeles|IrvineSanDiego Austin Environmental airspace: For raised access floors, the Decoupled systems: displacement technology works Higher discharge airtemperatures: Thisapproach calls 8. HV 7. skylightbuildingrelief withfan assist 6. atriumwithstack ventilation 5. floor diffusers 4. underfloor airdistribution 3. raised access floor 2. airhandlers 1. outsideairintake 8 A C return wallgrill 1 2 2 2 5 3 F or furtherin formati on, pleaseconta 4 7 vestas headquartersnightcooling five floors. cooling withinthecentral atriumandopenwork spaces across mass andanightpurge system asthe predominant meansof (15,979-square-meter) office willutilizeitsextensive thermal Air Change:Openingin2012,the172,000-square-foot 6 may require seismicrestraints according to code. the floor; like-wise, anythinghigherthan16 inches/0.4m additional airhandlingunitsto move aireffectively beneath there are exceptions, anyless vertical space mayrequire inches/0.3 to 0.4m,dependingonthefloor plate. While design spaceideal formovementair variesfrom to12 16 also meanhigherproductivity andfewer sickdays. which condition only the occupied space asairrisesup–can “single pass” designofdisplacement ventilation systems – throughout anoffice, distributing germs, dust anddirt,the air quality. While overhead ductwork promotes mixingofair demonstrate improved personal comfort andbetter indoor and savingsover timewithhigh office churnrates. the addedexpense interms ofimproved ventilation efficiency overhead systems. However, thebenefitsmay far outweigh to vendor, typeofflooring, grilles, etc.) thanconventional more persquare foot to install (estimates vary according of thesesystems. Raisedfloors, for example, cost $5to $10 cost becomes acritical factor indetermining thefeasibility FURTHER DESIGNFACTORS In addition,underfloor systems studies consistently Beyond programming andstructural considerations, c t usbyemail [email protected].

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