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Heating, Ventilation and Conditioning (HVAC) for Hospitals 1 Presentation for: Presented by Leach Wallace Associates September 8, 2011.

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Presentation on theme: "Heating, Ventilation and Conditioning (HVAC) for Hospitals 1 Presentation for: Presented by Leach Wallace Associates September 8, 2011."— Presentation transcript:

1 Heating, Ventilation and Conditioning (HVAC) for Hospitals 1 Presentation for: Presented by Leach Wallace Associates September 8, 2011

2 ● First Cost ● Energy Efficiency / O&M Cost ● Maintainability ● Reliability ● Redundancy ● Flexibility: ● Change in Occupancy ● Partial Renovation ● Redundancy ● Controllability: ● Temperature ● Humidity ● Pressurization ● Air Quality ● Infection Control ● Sound and Vibration Important Factors in the Selection of Hospital HVAC Systems

3 ● Packaged Air Handling Units ● Direct Expansion ● Chilled Water ● Local Special Systems ● Medical Equipment ● Computer Rooms ● Terminal Units ● Unitary or Served by a Central Plant. ● Fan Coil Units ● Incremental Units ● Heat Pumps ● Induction Traditional Hospital HVAC Systems Decentralized Systems

4 Packaged Terminal Air Conditioner filter front grille compressor wall sleeve condenser fan supply fan air-cooled condenser cooling coil

5 Water-Source Heat Pump refrigerant-to-water heat exchanger refrigerant-to-air compressor reversingvalve expansiondevice supply fan

6 Fan-Coil Unit cooling coil supply fan return-air inlet supply-air outlet filter

7 Fan Coil Systems 4 pipe 2 pipe Central ventilation unit

8 Induction Units 4 pipe 2 pipe Central ventilation unit

9 Air-Cooled Chiller, Fan-Coil System system-level controller air-cooled chiller fan-coil units dedicated outdoor-air unit hot-water boiler pumps exhaust fan

10 Small Chilled-Water System pump cooling coil controlvalve water chiller

11 Rooftop VAV System system-levelcontroller VAV terminals packaged rooftop air conditioner

12 Traditional Hospital HVAC Systems ● Could Still Utilize Unitary Equipment with All Air ● All Air Systems: ● Constant Volume Terminal Reheat ● Variable Air Volume ● Double Duct ● Central Heating: ● Boilers ● Central Cooling: ● Chillers Central Systems

13 Single Zone, Constant Volume coolingcoil RA EA OA supplyfan thermostat SA zone

14 Multiple Zones, Constant Volume coolingcoil RA EA OA supplyfan SA zone thermostat zone reheat coil

15 Multiple Zones, Variable Volume RA EA OA supplyfan zone thermostat zone VAV box SA coolingcoil

16 multiple zones, variable volume VAV Terminal Units cooling with reheat parallel fan-powered series fan-powered cooling only

17 multiple zones, variable volume Two-Fan, Dual-Duct VAV System EA OA PA cooling air handler PA RA heating air handler dual-duct VAV terminal units

18 multiple zones, variable volume Dual-Duct VAV Terminal Unit cool primary air warm primary air supply air

19 HVAC Filtration

20 Primary panel filter Secondary filter HEPA or tertiary filter

21 DecentralizedCentralized Installed CapacityGreaterLower First CostLowerHigher O&M CostHigherLower ReliabilityLowerHigher RedundancyLittleMore Flexibility to ChangeLittleMore ControllabilityPoor to GoodGood to Excellent TemperatureLimitedExcellent HumidityLimitedExcellent PressurizationLimitedBetter Sound/VibrationCan be an IssueBetter Infection ControlEquipment Can be in Occupied Areas Much Better Pro’s and Con’s of Decentral and Central HVAC Systems

22 Sources of Chilled Water Chilled water from a central plant Chilled water from a single building chiller Dedicated chiller for equipment or application

23 Cooling Sources Chiller Plant

24 Constant or Variable Flow-Primary-Flow Systems bypass two-wayvalve variable-flowpumps controlvalve checkvalves optional bypass with three-way valve

25 Primary-Secondary Configuration productionpumps two-way valve distributionpump distributionloop productionloop bypass pipe

26 Variable-Speed Drives variable- speed drive

27 Boiler Plant Steam vs. Hot Water Fire tube vs. water tube Full size vs. Modular Hot Water Only

28 What’s Changing Going Forward? ● LEED Requirements by the USGBC (Adoption by local authorities having jurisdiction) ● LEED for HealthCare



31 ● Energy Conservation a significant part. ● Establishes ASHRAE 90.1 for base performance. ● LEED forces early consideration of all measures, considers tradeoffs, evaluates the building in total. ● Energy modeling required. ● ASHRAE Standard 189.2P ● High Performance Healthcare Facilities ● Issued for public review March 1, 2011. ● Goal for Publication, June 2012. ● FGI – Guidelines for Construction of Hospitals. What’s Changing Going Forward?

32 ASHRAE Standard 90.1 - 2007 Energy standard for Buildings except low-rise Residential Buildings Purpose: To provide minimum requirements for the energy efficient design of building What does it apply to: ● New Building ● New portion of Buildings – Additions ● New Systems and Equipment in existing Buildings.

33 ASHRAE Standard 90.1 – 2007 Continued… Compliance with Standard Option 1: Prescriptive Method – Comply with the specific provisions of each section. ● Building envelope requirements based on climate zones ● Ex. U-Values (Insulation) ● Heating ventilation and air conditioning – Equipment efficiency and sizing. ● Service water heating – Equipment efficiency recovery requirements. ● Power – limitations and efficiency in usages. ● Lighting – limitations and efficiency in usages. ● Other equipment. Option 2: Energy Cost Budget Method ● Energy Modeling ● Evaluate proposed system operation using simulation software versus base building system type. ● Energy use and costs comparison.

34 ● Building Envelope Improvements ● Reduce Building Volume (Height) ● Reduce Fan Horsepower's. ● BIM as a resource. ● Requires less external static pressure. ● Larger ducts. ● Shorter horizontal duct runs. ● Moving away from traditional all air systems ● Dedicated ventilation air systems with exhaust heat recovery. ● Chiller ● Heat recovery ● Solar ● Hydronic ● PV Strategies to Reduce Energy Consumption

35 ● Heat Recovery Chillers ● Using the rejected condenser heat ● Heat Pumps ● Heat Recovery ● Laundry ● Data Centers ● Ground Source Heat Pumps ● Cogeneration ● Trigeneration Strategies to Reduce Energy Consumption Continued…

36 Ground-Source Heat-Pump System geothermal heat exchanger heat pump pumps

37 Cogeneration

38 Trigeneration

39 ● Reducing building height and horizontal duct lengths. ● Requires more vertical duct risers. ● Careful design can accomplish this but the duct shifts are restricted to layout. ● Code requirements to limit fan HP’s are forcing non all air solutions. ● In spite of the advantages there are limits as to what can be accomplished without signification costs. Reduce Building Volume/Reduce Fan HP’s for All Systems

40 Non All Air Systems ● Separate ventilation and dehumidification air systems to provide ventilation only. ● Local unitary equipment to accomplish sensible heating and cooling. ● All of these alternatives have drawbacks and risks. ● All provide less air delivery to control local pressurization.

41 Ventilation- Energy Recovery

42 Non All Air Alternatives ● Fan Coil Units ● Chilled Beams ● Positive Displacement Ventilation ● Hybrid VAV Systems

43 Active Chilled Beams In Cooling and Heating Mode

44 Passive Chilled Beams

45 Active Chilled Beams

46 Displacement Ventilation

47 What To Do Today ● Optimize Central Plant Performance ● Boilers ● Chillers ● Controls, Maintenance, Calibration and Monitoring ● Commissioning ● Retro Commissioning ● LEED for Existing Buildings

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