(Apr 12 2012) Chilled Beam Presentation

Twa Panel Systems Inc. April 12, 20121201 – 4th St.Nisku, Alberta, Canada P: +1 (780) 955-8757T9E 7L3 F: +1 (780) 965-8757www.twapanels.ca

Agenda

• Active Beam Origin

• Active Beam Overview

• How A.B.’s Function

• Construction

• System comparisons

• Air-side Information

• Water-side Information

• Capacity

• Benefits & Limitations

• Applications

Active Beam Origin

Passive Chilled Beams(1990’s)

Perimeter Induction Unit

(1950’s)

Modular Active Chilled Beams

(2000’s)

Radiant Panels(1950’s)

Chilled Sails

(1990’s)

•Origins in Europe

Active Beam Overview

• High acceptance rate in Europe• Historically high energy costs

• North American market increasing due largely to: • Green initiatives• Increasing energy costs• Increased installed base (Familiarity & Successful projects)• Lowering cost due to increasingly competitive market

Active Beam Overview

• Hydronic systems use water as the energy transport medium

• Water has many times the thermal capacitance as compared to air

Conduction Convection Radiation

Active Beam Overview

Modes of Heat Transfer

How A.B.’s Function

A – Duct connection S/A (primary Air) from the AHUB – Primary air (P/A) plenum Static Pressure forms and drives P/A through nozzlesC – Perforated grille Room air (Secondary air) is induced, through grille, into coilD – Unit mounted coil 2 or 4 pipe coil, cools/heats the secondary airE – Mixed air P/A and secondary air mixF – Discharge air Mixed discharge air exits the beam, Coanda is induced to throw the air horizontally

How A.B.’s Function

Construction Standard Beam Dimensions:Width: 1’, 2’Length: 2’, 4’, 6’, 8’, 10’

Standard Coil Lengths:2’, 3’, 4’, 5’, 6’, 7’, 8’, 9’, 10’

Various Nozzle Types• Induction Ratio• Acoustics

Discharge Pattern:1, 2, & 4 - way

Other:• Frame for Drywall• Exposed – Coanda

Wings

System comparisonsActive Beams• Low Energy Consumption• Reasonable Acoustics• Low maintenance costs (No moving parts)• Cooling Capacity: ~100 – 394 W/m2 (32 – 125 Btuh/ft2)

Versus

Fan Coil Units (FCU)• Medium/High Energy Consumption• Reasonable/Loud Acoustics• Adaptable Solution• Potential for high maintenance costs• Cooling Capabilities: ~100 – 200 W/m2 (32 – 64 Btuh/ft2)

Variable Air Volume (VAV) System• Low Energy Consumption• Quiet/Reasonable acoustics• Most efficient all air system• Cooling Capabilities: ~100 – 200 W/m2 (32 – 64 Btuh/ft2)

Variable Refrigerant Volume (VRV) System• High Energy Consumption• Reasonable Acoustics• Potential for high installation/maintenance costs• Cooling Capabilities: ~150 – 200 W/m2 (48 – 64 Btuh/ft2)

Air Side Information (Primary Air - Overview)

• Meet all ventilation requirements• Min. Vent. (O/A requirements)• Remove 100% of the latent loads (Psychrometrics)• Induce enough Rm./A to meet sensible loads

**Greatest of these factors sets the minimum air flow rate**

• Higher SAT may be used• May use heat recovery strategies for increased energy savings

• Decreased AHU & Duct size

• Decrease in fan energy

Air Side Information (Primary Air)

• Majority of energy is saved at the FAN

• Air-side Load Fraction (ALF)– The smaller the air-side load fraction, the more energy can be saved by

using a chilled beam system

Office Classroom Lobby

O/A Requirement(cfm/ft2)

0.15 0.5 1

Air Volume (All Air System) (cfm/ft2)

1 1.5 2

Air-side Load Fraction 15% 33% 50%

Air Side Information (Primary Air)

Air Side Information(Psychrometrics)

Psychrometric review required to prevent condensation

Standard Procedure:

• Remove moisture from the P/A at AHU

• Dry P/A lowers the space dew point temperature

• To prevent condensate on the coil:

Space dew point temp. < EWT

Not all spaces are suitable for active beams:

• Suitability engineering check - % of Sensible from

CFMLatent

Air Side Information(Psychrometrics)

Option 1 Option 2

Primary air dew point

48°F 51.5°F

Room air dew point

55°F 57.8°F

Secondary CWT

55°F 58°F

Dehumidification

0.002 lbs/lbDA 0.002 lbs/lbDA

RESET FOR ENERGY SAVINGS!

Legend:■ Easy , Application of active beam products is natural

■ Medium , Application of active beam products requires some additional design to control building moisture

■ Difficult, Application of active products is more difficult and humidity must be carefully considered

Air Side Information(Psychrometrics & Climate Regions)

Air Side Information(P/A Design Parameters)

Typical Design Conditions (Cooling):

S/A SpaceTDry Bulb: 55 - 65°F TDry Bulb: 75°FTWet Bulb: 53 - 57°F TWet Bulb: 64°FTDew point: 52°F TDew point: 58°F

R.H.: 55% ΔGr = 13.64 Gr/lb

Typical Design Conditions (Heating):

S/A SpaceTDry Bulb: 65°F TDry Bulb: 70°F

R.H.: 50%

QL = 0.68*CFM*ΔGr Qs = 1.08*CFM*ΔT

Air Side Information(Space Over Cooling)

• Maintain reasonable dew point control

• Meet 100% of latent load under Peak Design conditions

• Infiltration

• Maximum occupancy

• Other sources of moisture

• Limit over-cooling

• Keep air-side load fraction low

• Reset air temperature

• CHWS Shut-off control or EWT reset

• VAV for fluctuating occupancy

Air Side Information(Air Velocities & Thermal Comfort)

ASHRAE Std. 55

• Occupied Zone• ΔT and Air velocity

determine Thermal Comfort• 80% Occupancy Satisfaction• Radiant Affect

Active Beams

• Higher discharge air temp.• Highest air velocities are at

the perimeter of the space

Air Side Information(Air Velocities & Thermal Comfort)

Active Beam

Diffuser

Air Side Information(Plenum Air Pressure Drop)

50

70

90

110

130

150

170

190

210

230

250

0 5 10 15 20 25 30 35 40

Primary air [l/s]

Ple

num

Pre

ssur

e [P

a]

K 60A

K 60C

K 60D

K 60B

1.00”

0.93”

0.85”

0.77”

0.69”

0.60”

0.44”

0.36”

0.28”

0.20”

0.52”

10 21 32 42 53 64 74 85CFM

• Fan Static is higher

• Less penalty then high air flow

• Can correlate pressure and air flow

• Air volume is difficult to measure

• Measuring pressure is easy and reliable

• Pressure is the common factor

• Plenum and ducting should be sealed

Air Side Information(Acoustics)

0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.415

20

25

30

35

40

45

Plenum Pressure [“w.c.]

Lw

A [

dB

(A)]

Active beams can be very quiet!

Chart reports acoustic values

without roomattenuation

effect

2’x8’ – Smaller Nozzles

2’x8’ – Larger Nozzles

Air Side Information(Air Side Controls)

Tota

l cap

acity

Static pressure

• CAV primary air flow is typically simple with orifice plate “Iris” type dampers.• Varying the plenum

pressure yields a non-linear capacity response. Tight control with variable plenum pressure is typically impractical.

Air Side Information(Air Side Controls)

Tota

l cap

acity

Primary air volume

• Occupancy Valve may solve the issue of over-cooling a space with un-tempered primary air.

• Plenum static pressure range (0.3”-1.2” w.c. max)

• VAV modulation range is low with active beams

Air Side Information(Possible Dampers)

Iris Dampers – (angled multi-leaf

blades)

Iris Dampers

Pressure independent – butterfly type

Air Side Information(Common Design Pitfalls)

• Two Air-side Design Concerns:

1) Psychrometrics (Cooling only)

2) Preliminary Design based on DOAS system

Water Side Information (Overview)

• Coil responsible for majority of the sensible load• Cooling & Heating

• Design requires:• Water flow rate• Circuit pressure drop• Temperatures (EWT, LWT)

• Increase in pump size and pump energy• Fan Energy vs. Pump Energy = Net energy savings

Water Side Information (Water Design Parameters)

• Active Beam Cooling:• EWT temperature, typically between 56 – 62°F

• Secondary CHWS loop required

• Psychrometrics – (Condensation control)

• Generally EWT = 1 – 2 °F above SPACE dew point temp.

• Active Beam Heating:• EWT temperature, typically between 100 – 120°F

• Secondary HWS loop required

• Minimum flow rate per circuit = 0.45 to 0.65 GPM• Prevent laminar flow (more important for cooling)

Water Side Information (Piping Design)

Water system pressure control

• Variable speed pump and differential pressure sensor

• Reduces energy by lowering pump loading

• Maintain constant pressure

• Can cause imbalances in the system when not at full flow if pressure independent flow control valves are not used

Water Side Information (Piping Design)

Direct return• Length of pipe varies from supply

header to return header for each unit

• Change in pressure drop from one circuit to another, affects flow rates

• Use balancing valves or circuit setters

• Can cause imbalances in the system when not at full flow if pressure independent flow control valves are not used

Water Side Information (Piping Design)

Reverse return

• First supplied, last returned

• Zone or array is self-balancing

• Number of balancing valves can be reduced

• Additional pipe length required

• May require pressure independent flow control valves at mains for zone take off

Water Side Information (Piping Design)

Parallel piping

• Used exclusively for chilled beams

• Reduced pressure loss

• Lower flow rates to achieve ΔT

• Better temperature distribution and response

Water Side Information (Water Side Controls)

On/Off valve

• Inexpensive• Adequate control• Flow remains turbulent• Req’d for mix mode ventilation• Small & large zones

Proportional control valve

• Expensive• Advanced control not required• Flow becomes laminar (cooling)• Potential for searching

0 50 100

Seco

ndar

y Cap

acity

Water gpm

0.22 0.440

Turbulent flow

Laminar flow

Minimum flow rate per circuit = 0.45 to 0.65 GPM

Water Side Information (Common Design Pitfalls)

• Three water-side Design Concerns:1) Use of Glycol as the operating fluid

• Especially in cooling

2) Not considering Pressure independent flow control valves

• Especially with large hydronic systems

• Modulating valves

• Variable frequency drive pumps

3) Valve & Entrapped air noise

Capacity Overview

Air Side:

• 100% Latent energy capacity, increase by:• Increasing ΔGr between P/A & Rm/A• Increasing air flow rate

• Minority of sensible capacity, increase by:• Increasing ΔT between P/A & Rm/A• Increasing air flow rate

Water Side:

• Majority of sensible capacity, increase by:• Increasing ΔT between water & Rm/A• Increasing water flow rate

Total Capacity = Air capacity + Water capacity

5

10

15

20

25

30

35

40

100 200 300 400 500 600 700 800

Air

Vo

lum

e [

l/s]

Secondary Capacity [W]

A-DT 8A-DT 10B-DT 8B-DT 10C-DT 8C-DT 10D-DT 8D-DT 10

Typical sensible range is approx. 250 – 1500 BTUh/Ft

• Increasing air flow rate and pressure:

• Significant Increase in Capacity

• Increasing GPM in turbulent flow:

• Marginal Increase in Capacity

Capacity vs. Air Volume

Capacity(Performance Data)

• Applicable standards:• EN 15116: Chilled Beams• ASHRAE/AHRI - SPC 200

• When choosing a manufacturer, ensure they test to an applicable standard!

Active Beam Benefits• Significant Fan Energy savings

• lower overall S/A

• Increased air circulation with high thermal comfort

• Smaller AHU & Ductwork• Lower floor-floor heights• Good retrofit applications• Significant reduction of riser space

• Low maintenance requirements

• Can be integrated with other energy saving systems• Geothermal, ERV’s, Enthalpy wheel…etc

• Water side free cooling may be an option

Active Beam Benefits

• Spaces may be zoned• Increased Comfort• Reduced energy consumption• Individual space temperature control (LEED Compliant)

• Quick response time

• Low to Reasonable Acoustics

Active Beam Limitations

• Potential for higher first cost• Increase in pump energy

• Small Compared to Fan Energy Savings

• Limited air-side free cooling

• Limited VAV modulating range

• High importance for building humidity control in Cooling• Dehumidification at the AHU is required• May require a building envelope upgrade• May require more sophisticated controls for humidity control• May not be acceptable for all spaces, based on latent loads

ApplicationsCommercialOffice spacesData centersShops/Stores

InstitutionalLabsLecture Theatres*

GovernmentSchoolsHospital**AirportsClinics

OtherChild care facilities

*Occupancy may produce high latent requirements**Some areas such as surgical suites do not allow room air to be induce or circulated through the HVAC equipment

Sensible and Latent energy drive suitability

Higher the sensible - the greater the energy savings

Lower the latent - the easier it is to control the dew point temperature of the space (Required due to no condensate pan)

Spaces with:

• High sensible loads & low latent loads • Ideal

• High sensible loads & high latent loads • May be suitable with careful examination

• Low sensible loads & high latent loads • Would not be recommended for use with chilled beams

Not a silver bullet, each space should be individually reviewed to determine suitability

Applications

Open Office Area

Applications

Individual Office Area

Applications

Child Care Center

Applications

Coffee Shop

Questions