3 Mechanical SystemsInstall the smallest, most efficient system possible:Reduce perimeter loads through careful skin design.Reduce internal loads: laptops, energy star equipment.Multnomah County Hillsdale LibraryArchitect: Thomas Hacker and Associates
4 What Factors Determine the Mechanical System Selected? Building TypeOfficeHousingEducation, Higher Ed or SecondaryIndustrialMaintenanceComfortMark O. Hatfield US CourthouseArchitect: BOORA ArchitectsSokol Blosser Wine Barrel Storage FacilityArchitect: SERA Architects
7 Active Systems Cooling Heating Air Distribution COOLING Direct ExpansionPackaged RooftopChilled WaterAir CooledWater Cooled CentralGround WaterDirect and IndirectEvaporative CoolingDistributed Heat PumpsActive SystemsCoolingHeatingAir DistributionHEATINGHydronicConventional Hot Water BoilersHigh Efficiency Hot Water Boilers (Gas)Electric HeatGas FiredGround Coupled Heat PumpAIR HANDLINGCentralRooftopPenthouse or InsideDistributed Air HandlingFan CoilsUnit VentilatorsHeat Pumps
8 Active Cooling Systems Direct expansionChilled water- Air cooled- Water cooled- Ground WaterDirect and indirectevaporative coolingDistributed heat pumps
9 Cooling Systems Chilled Water Package Rooftop First Cost: Lowest potential first cost.Energy Cost: Higher energy cost.Maintenance: High maintenance costs - expected life of 15 years.Comfort: Reasonable – potential acoustical issues.University of Oregon School of Music & DanceArchitect: BOORA Architects
10 Cooling Systems Chilled Water Air Cooled First Cost: In conjunction with air handlers.Energy Cost: Better than rooftop option.Maintenance: Lowest maintenance cost option - average life of 17 years.Comfort: High level of comfort.
11 Cooling Systems Water Cooled First Cost: Greatest first cost. Energy Cost: Lowest Energy cost.Maintenance: Equipment is highly reliable - chiller life is 27 years.Comfort: Provides the best in comfort - quiet operation.
12 Ground Source Heat Pumps GS heat pumps extract geothermal energy to condition buildings.Very low energy consumption.Winter – moves heat from the earth to the buildingSummer – moves heat from the building to the earthAutomatic controls are used to reverse the direction of the heat transfer
13 Ground WaterPSU Northwest Center for Engineering, Science and Technology.Ground water well system with extraction and insertion wells.No Boiler or Cooling TowerGround water is used for heating and cooling.
14 Heating Systems Active Systems – Heating Hydronic - Hot water boiler - High efficiency boiler - condensingElectric heatGas fired
15 Heating Systems Hydronic Heating Systems Energy Cost: Mid range, between electric heat and high efficiency hot water.Maintenance: Requires little maintenance.Comfort: Excellent comfort.
16 Radiant Floor Heating Consistent heating Low energy usage Slow response time
17 Heating Systems Electric Heat First Cost: Low first cost. Energy Cost: Very high. This will represent a 100% to 150% increase in energy cost due to rate differences between gas and electric.Maintenance: Low maintenance.Comfort:Step control on electric heaters. Acceptable comfort.
18 Active Systems – Air Handling CentralDistributed- Fan Coils- Unit Vents- Heat Pumps
19 Air Handling Package Air Handler Variable Air Volume Air Handler Distribution:Conventional overheadUnderfloorLower energy savings - longer economizer cycleSmaller cooling zone
20 Air Handling Systems Heat Recovery Energy cost: Low energy cost. Maintenance: Same as air handler.Comfort: Less than air handler, if provided without coils.
22 Advantages of Natural Ventilation SimpleLower first cost (15% less)Lower operating cost (40% less)User satisfaction through greater controlElimination of mechanical refrigerationLess environment impactNo mechanical noise
23 Advantages of Natural Ventilation Option A SimpleLower first cost (15% less)Lower operating cost (40% less)User satisfaction thru greater controlElimination of mechanical refrigerationLess environment impactNo mechanical noiseinspire interpret integrate
24 Disadvantages of Natural Ventilation Temperature & humidity cannot be tightly controlledNo filtrationReduced securityFirst cost higher if back-up A/C system is also requiredExterior noise can be a problemLess flexible air intake locations – air quality issuesLarge openings required with massinspire interpret integrate
25 Disadvantages Temperature and humidity cannot be tightly controlled No filtrationReduced securityFirst cost higher if back-up A/C system is also requiredExterior noise can be a problemLess flexible air intake locations – air quality issuesRain
27 Washington School for the Deaf Classroom Natural VentilationDaylightingThermal MassNight FlushNo Filtration
28 Thermal Mass / Night Ventilation Need approximately 2 to 3 times the floor areaCan reduce maximum daytime temperature
29 Sustainable Design Mechanical Systems What system? That depends . . .Reduce loads to lowest possible amountKnow your client, maintenance, comfort, operating schedule, etc.Select most efficient system possibleSystem Types- Active- Passive- Mixed Mode
30 Shattuck Hall – Case Study Existing Mechanical Systems Two dedicated outside air units with steam heat, evaporative air cleanersMultiple air zones with mix dampersGravity relief from each zone (open relief duct on roof)Other smaller mechanicalsystems.pae consulting engineers, inc.inspire interpret integrate
32 Old Zone Dampers - Mixing inspire interpret integrate
33 Mechanical Systems Options HVAC Option C – Conventional VAVHot water heatingVariable volume AHU’sMedium pressure supply ductworkVAV air terminal units in each spaceLow pressure return ductworkReturn air plenumsHVAC Option D – Dedicated OA/RadiantHot water heating radiant panelsFan-induced ventilationOperable windows – manualNew AHU’s/Existing ductwork - for minimum outside airRadiant Cooling – radiant cooling panels or chilled beamsHVAC Option A – “Natural” VentilationHot water heating radiatorsOperable windows – automatic, with trickle ventsBuilding Mass/Night Flush Cooling HVAC Option B – “Natural” Ventilation/Mixed ModeFan-induced ventilationOperable windows automaticNew AHU’s/Existing DuctworkCooling coils in new AHU’s deliver cold air through existing ductwork on extremely hot dayspae consulting engineers, inc.inspire interpret integrate
34 Shattuck Hall New Mechanical Systems Two dedicated outside air units with hot water heating, campus chilled water and filtersTemperature zones with VAV terminal unitsRadiant heating and cooling panelsGravity relief from each zone (open relief duct on roof)Other smaller mechanicalsystems.pae consulting engineers, inc.inspire interpret integrate
35 Estimated Energy Usage Energy Use in Shattuck HallEstimated Energy UsageNo envelope upgradesinspire interpret integrate
36 Radiant Panel Concerns Guinea Pig or InnovativeComfortNoiseCondensateValve locationsHot water leaksFlexibilityinspire interpret integrate
37 Radiant Panels and Valves inspire interpret integrate