Chilled Beam and Radiant Cooling Basics. Salt Lake City, UT ASHRAE Chapter December 2013 Nick Searle

Transcription

1 Chilled Beam and Radiant Cooling Basics Salt Lake City, UT ASHRAE Chapter December 2013 Nick Searle

2 Contents Radiant Ceilings & Chilled Beam Basics Energy & Space Savings First and Lifecycle Costs Maintenance Application Suitability Design Considerations Application Example # Laboratories Case Study 250 S. Wacker, Chicago

3 Fan Energy Use in Buildings 4.5 Chiller/Compressor 7 Design Load KW/SF Supply & Return Fans Chilled Water Pump Condenser Water Pump Cooling Tower Fan Condenser Fan Energy Use KWh/SF Central VAV Central CAV Packaged CAV 0 Central VAV Central CAV Packaged CAV Energy Consumption Characteristics of Commercial Building HVAC Systems publication prepared for U.S. Department of Energy

4 Water = Efficient Transport 10 1 Ton of Cooling requires 550 CFM of air or ¾ diameter water pipe 4 GPM of water

5 Chilled Ceilings Chilled Ceilings Many buildings heated only PC s appearing on desks Restricted ceiling cavity

6 Chilled Ceilings Radiant Effect CW Supply 5962 F CW Return 6266 F 45% Radiant 55% Convective 76 F Dry Bulb 74 F radiant temperature (black bulb)

7 Chilled Ceilings Advantages Excellent thermal comfort Reduced space requirements Will fit into 6#8 cavity Self regulating Simple controls Low noise Low maintenance Design Issues Low cooling output 20 to 25 BTUH/ft 2 100% coverage 14 to 18 BTUH/ft 2 70% coverage High cost Separate air system required

8 Chilled Sails

9 Chilled Sails

10 Chilled Sails Advantages Good thermal comfort Reduced space requirements Freely suspended Self regulating Simple controls Low noise Low maintenance Design Issues Cooling output 40 to 50 BTUH/ft 2 Separate air system required High cost Cannot heat Need good acoustic treatment to avoid hard spaces Many connections Aesthetics?

11 Passive Chilled Beams Chilled Ceilings Passive Chilled Beams Increased cooling loads Equipment Occupancy Day#lighting Inadequate perimeter cooling

12 Passive Chilled Beams 1 Operation Principle Soffit Suspension rod Water coil Fabric skirt Perforated tile

13 Passive Chilled Beams 1 System Highlights Good thermal comfort Cooling capacity up to 40 BTUH/FT 2 floor space Up to 500 BTUH per LF of beam Reduced ductwork, riser and plant sizes Water transports most of sensible cooling Self regulating simple two position controls Low noise Low maintenance

14 Design Considerations Sensible cooling only Latent gains must be controlled by air system High free area perforated metal ceiling required 28% free area minimum Exposed beams (no ceiling) are an option Beams cannot be installed tight against slab Typically 40% of beam width required above beam Separate heating system must be installed Separate air system must be installed

15 Passive Chilled Beams 1 Airflow Pattern

16 Passive Chilled Beams 1 Recessed Type

17 Passive Chilled Beams 1 Exposed Type

18 Active Chilled Beams Chilled Ceilings Passive Chilled Beams Active Chilled Beams Higher space loads Higher occupant densities Combined ventilation/cooling preferred Integration into fiber tile ceilings required

19 Active Chilled Beam 1 Operation Principle Primary air nozzles Primary air plenum 1 Part Primary Air Suspended ceiling Heat exchanger 4 Parts Room Air

20 Heat Removal Ratio Airflow requirement reduced by 70% 70% of sensible heat removed by chilled beam water coil

21 Active Chilled Beam 1 Airflow Pattern

22 Active Chilled Beams 1 System Highlights Very high cooling capacity Up to 100 BTUH/FT 2 floor space Up to 1500 BTUH per LF Integrated cooling, ventilation and heating All services in the ceiling cavity Suitable for integration into all ceiling types Reduces ceiling costs compared to Passive Beams

23 Active Chilled Beams 1 System Highlights Significant space savings Smaller ductwork saves space in shafts, plant rooms and ceiling Can be installed tight up against the slab Reduced floor to floor heights Reduced construction costs on new buildings Low noise levels Low maintenance No moving or consumable parts

24 Energy Savings 1 Compared to VAV Source Technology Application % Saving* US Dept. of Energy Report (4/2001) Beams/Radiant Ceilings General 25#30 ASHRAE 2010 Technology Awards Passive Chilled Beams Call Center 41 ACEE Emerging Technologies Report (2009) Active Chilled Beams General 20 ASHRAE Journal 2007 Active Chilled Beams Laboratory 57 SmithGroup Active Chilled Beams Offices 24 *Compared to VAV Energy Consumption Characteristics of Commercial Building HVAC Systems publication prepared for U.S. Department of Energy

25 Active Chilled Beams 1 First Costs Office Building, Palo Alto, CA 80,000 ft 2 Thermostat in each office for beam design costs were in line with VAV * *HPAC Engineering Article European Technology Taking Hold in the U.S.: Chilled Beams, Peter Rumsey, PE, CEM, FASHRAE, FRMI

26 Active Chilled Beams 1 First Costs Office Building, Denver, CO 600,000 ft 2 design/build renovation Elimination of two air handlers per floor due to beams the chilledbeam system was equal to the VAV system * *HPAC Engineering Article European Technology Taking Hold in the U.S.: Chilled Beams, Peter Rumsey, PE, CEM, FASHRAE, FRMI, January 1 st 2010

27 Active Chilled Beams 1 Lifecycle Costs 100,000 ft 2 Office Building, Cincinnati, OH 15 year lifecycle study 15% Energy Savings Compared to VAV $0.79 versus $0.93 ft 2 22% reduction in mechanical installation costs $19.50 versus $25.00 per ft 2 Lifecycle costs analysis over 15 years Favored chilled beam system by 20% $32 ft 2 versus $40 ft 2 HIXSON ARCHITECTURAL INTERIORS Spring 2009

28 LEED Certification 1 LEED NC V3.0 Optimize Energy Performance # up to 48% (new) or 44% (existing) more efficient than ASHRAE 90.1 (EA Credit 1) # up to 19 points Increased Ventilation # 30% more outdoor air than ASHRAE 62 (IEQ Credit 2) # 1 point Controllability of Systems # individual temperature control (IEQ Credit 6.2) # 1 point Thermal Comfort # meet ASHRAE 55 (IEQ Credit 7.1) # 1 point (Minimum 40 points needed for certification out of 100 maximum)

29 Maintenance No moving parts No filter No condensate pumps No consumable parts Up to 4 year inspection & clean Easy maintenance access

30 Cleaning Access

31 Active Chilled Beams 1 Typical Installation

32 Active Chilled Beams 1 Typical Installation

33 Active Chilled Beams 1 Typical Installation

34 Concealed Active Beams

35 Bulkhead Active Chilled Beams

36 ACTIVE CHILLED BEAM DESIGN CONSIDERATIONS

37 Building Suitability Building Characteristics that favor Active Chilled Beams Zones with moderate#high sensible load densities Where primary airflows would be significantly higher than needed for ventilation Sensible Heat Ratio s (SHR) of 0.8 and above Buildings most affected by space constraints Hi rises, existing buildings with induction systems Zones where the acoustical environment is a key design criterion Laboratories where sensible loads are driving airflows as opposed to air change rates Buildings seeking LEED or Green Globes certification

38 Building Suitability Characteristics that less favor Active Chilled Beams Buildings with operable windows or leaky construction Beams with drain pans could be considered Building pressurization control should be used Zones with relatively low sensible load densities Zones with relatively low sensible heat ratios and low ventilation air requirements Zones with high filtration requirements for the re# circulated room air Zone with high latent loads

39 APPLICATION EXAMPLE: LABORATORIES

40 Laboratory Design Issues Sensible heat gains of up to 70 BTUH/ft 2 Space ventilation requirements of 6 to 8 ACH Laboratories where chemicals and gases are present require 100% outdoor air Air systems require 15 to 20 ACH of outside air to satisfy sensible load

41 Cooling Load and ACH

42 Benefits of Active Beams in Labs Eliminated or reduced reheat Reheat can account for 20% or more HVAC energy costs Water more efficient transport medium Reduces fan energy costs Smaller space requirements System sized for 6 ACH instead of 15 ACH

43 Active Chilled Beam Design Cooling Load = 65 BTU/H ft 2 Ventilation Rate = 6 Air Changes VAV Solution = 15 Air Changes Chilled Beam Solution = 6 Air Changes Active Chilled Beam Solution = 6 x 6 Long, 130 CFM each

44 Reheat Reduction VAV System Minimum Airflow 6 ACH = 760 CFM Cooling Load 65 BTU/H ft 2 41,000 BTU/H Peak Maximum Airflow 1,860 CFM (15 ACH) Minimum Cooling without reheat 6 55 F 16,600 BTU/H Turndown without reheat 16,600/41,000 59% ACB System Minimum Airflow 6 ACH = 760 CFM Cooling Load 65 BTU/H ft 2 41,000 BTU/H Peak Maximum Airflow 760 CFM Minimum Cooling without reheat 6 65 F 8,300 BTU/H Turndown without reheat 8,300/41,000 80%

45 CASE STUDIES

46 250 South Wacker Chicago, IL

47 250 S. Wacker, Chicago 1Case Study 16#story tower 215,000 sq. ft. 1st floor retail 2 16th floor offices Separate HVAC systems for 1st and 16th floors Perimeter induction system with floor#mounted units serving 2 #15th floors Interior constant volume/ variable temperature system serving 2 15th floors

48 250 S. Wacker, Chicago Case Study Building Renovated with 1 100% glazing with E#glass (190 Btuh/Ln.ft. heat loss) Single duct cooling only VAV interior system Evaluated fan#powered VAV or active chilled beam perimeter system Seeking LEED certification

49 250 S. Wacker, Chicago Case Study Perimeter System Type Existing Induction System Proposed Fan#powered VAV System ** Proposed Active Chilled Beam System ** Design Cooling Load 262 tons (382 sq.ft./ton) 156 tons (641 sq.ft./ton) 156 tons (641 sq.ft./ton) Primary Airflow 25,600 cfm (0.5 cfm/sq.ft.) 86,270 cfm (1.7 cfm/sq.ft.) 15,880 cfm (0.3 cfm/sq.ft.) Fan Energy at Design Fan Energy at 70% of Design 64 kw 182 kw 22 kw 64 kw 116 kw 22 kw Pump Energy 28 kw 8 kw 12 kw Combined Fan & Pump Energy 92 kw 190 Design % 34 kw ** Required larger ductwork/risers ** Used existing ductwork/risers

50 250 S. Wacker, Chicago Case Study

51 S. Wacker, Chicago Case Study

52 QUESTIONS?