Chilled Beam and

Radiant Cooling Basics

Salt Lake City, UT ASHRAE Chapter

December 2013Nick Searle

nsearle@dadanco.com

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

Fan Energy Use in Buildings

“Energy Consumption Characteristics of Commercial Building HVAC

Systems” � publication prepared for U.S. Department of Energy

0

0.5

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4.5

Central VAV Central CAV Packaged CAV

Desig

n L

oad

KW

/SF

Chiller/Compressor

Supply & Return Fans

Chilled Water Pump

Condenser Water Pump

Cooling Tower Fan

Condenser Fan

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1

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Central VAV Central CAV Packaged CAV

En

erg

y U

se K

Wh

/SF

Water = Efficient Transport

¾” diameterwater pipe

10”

1 Ton of Cooling

requires 550 CFM of air

or

4 GPM of water

Chilled Ceilings

Many buildings heated only

PC’s appearing on desks

Restricted ceiling cavity

1980 1990 2000 2010

Chilled Ceilings

Chilled Ceilings Radiant Effect

45%Radiant

55%Convective

CW Supply59�62°F

CW Return62�66°F

76°F Dry Bulb

74°F radiant

temperature

(black bulb)

Chilled CeilingsAdvantages Design Issues

• Low cooling output‒ 20 to 25 BTUH/ft2 100%

coverage‒ 14 to 18 BTUH/ft2 70% coverage

• High cost

• Separate air system required

• Excellent thermal comfort

• Reduced space requirements‒ Will fit into 6#8” cavity

• Self regulating‒ Simple controls

• Low noise

• Low maintenance

Chilled Sails

Chilled Sails

Advantages Design Issues

• Cooling output‒ 40 to 50 BTUH/ft2

• Separate air system required

• High cost

• Cannot heat

• Need good acoustic treatment to avoid hard spaces

• Many connections

• Aesthetics ?

• Good thermal comfort

• Reduced space requirements

• Freely suspended

• Self regulating

• Simple controls

• Low noise

• Low maintenance

Chilled Sails

Passive Chilled Beams

• Increased cooling loads‒ Equipment‒ Occupancy‒ Day#lighting

• Inadequate perimeter cooling

1980 1990 2000 2010

Chilled Ceilings

Passive Chilled Beams

Passive Chilled Beams 1 Operation Principle

Perforated tile

Water coil

Suspension rod

Soffit

Fabric skirt

Passive Chilled Beams 1 System Highlights

• Good thermal comfort

• Cooling capacity up to 40 BTUH/FT2 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

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

Passive Chilled Beams 1 Airflow Pattern

Passive Chilled Beams 1 Recessed Type

Passive Chilled Beams 1 Exposed Type

Active Chilled Beams1980 1990 2000 2010

Chilled Ceilings

Passive Chilled Beams

Active Chilled Beams

• Higher space loads

• Higher occupant densities

• Combined ventilation/cooling preferred

• Integration into fiber tile ceilings required

Active Chilled Beam 1 Operation Principle

Suspended ceiling

Primary air plenum

Primary air nozzles

Heat exchanger

1 Part Primary Air

4 Parts Room Air

Heat Removal Ratio

70% of sensible heat removed by chilled beam

water coil

Airflow requirement

reduced by 70%

Active Chilled Beam 1 Airflow Pattern

Active Chilled Beams 1 System Highlights

• Very high cooling capacity‒ Up to 100 BTUH/FT2 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

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

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

Active Chilled Beams 1 First Costs

• Office Building, Palo Alto, CA

• 80,000 ft2

• Thermostat in each office for beam design

*HPAC Engineering Article “European Technology Taking Hold in the U.S.: Chilled

Beams, Peter Rumsey, PE, CEM, FASHRAE, FRMI

“costs were in line with VAV”*

Active Chilled Beams 1 First Costs

• Office Building, Denver, CO

• 600,000 ft2 design/build renovation

• Elimination of two air handlers per floor due to beams

*HPAC Engineering Article “European Technology Taking Hold in the U.S.: Chilled

Beams, Peter Rumsey, PE, CEM, FASHRAE, FRMI, January 1st 2010

“the chilled�beam system was equal

to the VAV system”*

Active Chilled Beams 1 Lifecycle Costs

• 100,000 ft2 Office Building, Cincinnati, OH

• 15 year lifecycle study

• 15% Energy Savings Compared to VAV‒ $0.79 versus $0.93 ft2

• 22% reduction in mechanical installation costs‒ $19.50 versus $25.00 per ft2

• Lifecycle costs analysis over 15 years‒ Favored chilled beam system by 20%‒ $32 ft2 versus $40 ft2

HIXSON ARCHITECTURAL INTERIORS � Spring 2009

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)

Maintenance

• No moving parts

• No filter

• No condensate pumps

• No consumable parts

• Up to 4 year inspection & clean

• Easy maintenance access

Cleaning Access

Active Chilled Beams 1 Typical Installation

Active Chilled Beams 1 Typical Installation

Active Chilled Beams 1 Typical Installation

Concealed Active Beams

Bulkhead Active Chilled Beams

ACTIVE CHILLED BEAM DESIGN

CONSIDERATIONS

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

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

APPLICATION EXAMPLE:

LABORATORIES

Laboratory Design Issues

• Sensible heat gains of up to 70 BTUH/ft2

• 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

Cooling Load and ACH

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

Active Chilled Beam DesignCooling Load = 65 BTU/H ft2

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

Reheat ReductionVAV System ACB System

• Minimum Airflow‒ 6 ACH = 760 CFM

• Cooling Load‒ 65 BTU/H ft2

‒ 41,000 BTU/H Peak

• Maximum Airflow‒ 760 CFM

• Minimum Cooling without reheat‒ 6 ACH @ 65°F

‒ 8,300 BTU/H

• Turndown without reheat‒ 8,300/41,000‒ 80%

• Minimum Airflow‒ 6 ACH = 760 CFM

• Cooling Load‒ 65 BTU/H ft2

‒ 41,000 BTU/H Peak

• Maximum Airflow‒ 1,860 CFM (15 ACH)

• Minimum Cooling without reheat‒ 6 ACH @ 55°F‒ 16,600 BTU/H

• Turndown without reheat‒ 16,600/41,000‒ 59%

CASE STUDIES

250 South Wacker

Chicago, IL

250 S. Wacker, Chicago 1 Case Study

• 16#story tower –215,000 sq. ft. 1st floor retail2 – 16th floor offices

• Separate HVAC systemsfor 1st and 16th floors

• Perimeter induction systemwith floor#mounted unitsserving 2 # 15th floors

• Interior constant volume/variable temperaturesystem serving 2 – 15th floors

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 oractive chilled beamperimeter system

• Seeking LEEDcertification

250 S. Wacker, Chicago – Case StudyPerimeter SystemType

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

64 kW 182 kW 22 kW

Fan Energy at 70% of Design

64 kW 116 kW 22 kW

Pump Energy 28 kW 8 kW 12 kW

Combined Fan & Pump Energy

92 kW 190 kW @ Design

124 kW @ 70%

34 kW

** Required larger ductwork/risers ** Used existing ductwork/risers

250 S. Wacker, Chicago – Case Study

25 250 S. Wacker, Chicago – Case Study

QUESTIONS?