Active Beam Commissioning Overview

OPERATION & COMMISSIONING OF
ACTIVE BEAMS

Twa Panel Systems Inc.
1201 – 4th Street
Nisku, AB
Canada, T9E 7L3
(780)-955-8757

www.twapanels.ca

Introduction to Active (Chilled) Beams

Introduction to Active Beams
Fan energy savings

De-coupled ventilation systems

Energy Usage Noise Level Output Comments

Adaptable
Fan Coil Units Medium/High Medium 32-64 Btuh/ft2
solution

VAV Systems Very efficient
Low Low/Medium 32-64 Btuh/ft2
all-air system

VRV System
(Variable Possible high
Refrigerant High Medium 48-64 Btuh/ft2 maintenance
Volume) costs

Very low
Active Beams
Low Low 32-125 Btuh/ft
2
maintenance
costs

Principles of operation

Active beam benefits
1) Lower overall air volume processed by the primary air handling unit. (0.25-0.5 cfm/ft2)
2) Higher entering chilled water temperatures: (55°F-61°F).
3) Lower hot water temperatures: Select beams for cooling duty, then choose
appropriate hot water temperature for heating.
(i.e. usually less than 120°F. Beam discharge air
should be less than 15oF warmer than room design
temperature to limit the risk of stratification.
4) Suitable for use with water-to-water heat pumps, and has the potential to double the
COP of a dedicated chiller loop.
5) Self regulating secondary capacity: Approach = Room Temperature - Supply water
temperature
6) VAV control: Can be used to strictly limit room air velocity, provide linear
temperature control, and additional fan energy savings for areas with
highly variable latent loads.
(i.e. Labs, Boardrooms, coffee rooms, classrooms, etc…)

Suitable areas for active beams

Psychrometrics

Option 1 Option 2

Primary air dew
48°F 51.5°F
point
Room air dew
55°F 57.8°F
point

Secondary CWT 55°F 58°F

Dehumidification 0.002 lbs/lbDA 0.002 lbs/lbDA

RESET FOR ENERGY
SAVINGS!

Condensation risks
Areas of greatest condensation risk:
1) Near points of entry to the building
4)At the perimeter, with mixed-mode ventilation
5)Structures with poor building envelopes, including retrofit applications
6)In areas with highly variable latent loads:
• Board rooms
• Lunch / coffee rooms
• Etc…
Condensation prevention strategies may include:
10)De-activation of secondary chilled water supply, by zone, via loss of dew-point from
sensors mounted to CWS lines. (… or via combination: DB / RH zone stats, or
other…)
2) Tempering secondary chilled water supply by zone via:
• Three-way mixing valve
• Injection pumps
3) Etc…

DOAS Information Resource

1) http://doas.psu.edu/

2) Not all primary air handling systems are DOAS!

Placement within the ceiling

P2 drops rapidly
moving into the
room

P3 = ½ at 3ft into
occupied zone

Inherent comfort with active beams

Active Beam

Diffuser

Beam acoustics

Chart reports
acoustic values
without room
attenuation
effect

Active beams can
be very quiet!

1/3rd Octave band analysis

Owens Corning Acoustic Testing
•Acoustic test standards may include:
 ISO3741
 ASHRAE Std. 70

• Reverberant chamber (No Attenuation)

Manufacturer A = Worst Case
• 2’ x 8’ – D nozzle @ 1.20”w.c.
• Peak in the 2.5 KHz Band
• Lw (dB) = 39.1
• LwA (dBA) = 38.8
• NC = 24 !

Installation and maintenance
Fastening beams to the structure

Upstream damper
at SMACNA
recommended
minimum distance

Drywall

N.B. - Include seismic restraint
where required by code

T-bar mounting detail

Width Length

Exposed / pendant type units

Coanda wings
required for
proper throw
characteristics

Installation “Tips”

1. “Rough-in”: piping, ducting, concrete threaded inserts, and beams, prior
to T-bar installation. Lower beams into T-bar for final positioning.

3. Store beams on-site indoors whenever possible, in a low traffic area, and
otherwise covered for protection from the elements.

5. Leave plastic film on each unit to minimize site damage, and prevent coil
/ unit fouling.

7. Match beam label to schedule; - beams look alike! Confirm that the right
beam is in the right room. Contractor suggestion: - Confirm packing slip
matches shop drawing requirements upon receipt of material.

9. Limit flexible duct to no more than 10’. Avoid sharp turns in ductwork.

Installation “Tips”

1. Plan for access doors, and possibly welded-aluminum frames, with beams
mounted in dry-wall ceilings.

3. Manage glazing surface temperatures by planning discharge
configuration. With high quality glass, beams which discharge
perpendicular to the glazing, are typically preferred.

5. Stainless steel flexible hoses allow for some adjustment within the ceiling
grid.

Sample active beam packaging

nits remain “as-new”

until final
commissioning

and “turn-over”.

ecyclable packaging

materials.

ace-to-face, and back-
to-back crating mini-
mizes shipping damage.

Beams mounted with aircraft cable

Note protective
film at inlet of
unit mounted coil

IOM and precautions

ead the manufacturer’s Installation Operation and Maintenance Manual

ay particular note of any precautions which have been identified as high
risk conditions. (i.e. minimum two people to handle beams 6’ and larger,
pulling on un-latched door may cause hardware failure, be cautious of
sharp edges, limit flex duct connections to 10’ maximum, etc…)

o NOT circulate water through the beam mounted coil until the “mains”
have been properly “de-greased” / flushed.

o NOT remove protective plastic film from beam body until the space has
been appropriately cleaned, to minimize fouling of the coil

O lower the secondary chilled water temperature slowly to limit the risk of
condensation damage during start-up.

Coil maintenance

ctive beams require practically no maintenance. If the coil remains dry, as
expected, there is very little risk of fin “bridging”.

ecommended cleaning schedules typically involve lowering, or removing
the perforated doors / panels, in front of unit mounted coil, at 6-Months,
and 1-Yr., to establish a maintenance schedule. Areas with higher airborne
contamination require more frequent cleaning.

ften, cleaning schedules can extend to between 3-5 years in spaces subject
to weekly housekeeping.

igher housekeeping frequency, reduces the intervals between coil

Coil maintenance

Vacuum with or
without a “horse-
hair” bristle brush

Unit cleanliness prior to start-up

eave active beams wrapped to prevent fouling unit or coil.

ipe unit with a damp rag to remove surface dirt, or vacuum with a horse-
hair bristle brush.

o NOT scrub the paint. Damage to the finish may occur.

soft bristle brush and mild detergent with water, can be used to remove
stubborn “smudging”, if required.

eams ship with repair kits for surface scratched units. Do NOT spray the
unit directly with “spray-bomb” type matched paint. Use artist paint

Air-side control and measurement

Ducting for equal static pressure

Pt = Ps + Pv
Pt = total pressure (”w.c.)
Ps = static pressure (”w.c.)
Pv = velocity pressure (”w.c.)
If velocity pressure is kept negligibly low, then the same static pressure will
hold throughout the duct. ( i.e. Only if transport loss can be neglected).

Pv = 0,5 x r x v2
Pv = velocity pressure (”w.c.)
r = air density (0.075 lbs/ft3)
v2 = air velocity (fpm)
At < (590 fpm) duct air velocity Pv < (0.02”w.c.)
At < (590 fpm) transport
Ø = (5”) < (0.001”w.c/ft.)
Ø = (8”) < (.0007”w.c./ft.)
Low air volumes required for beams makes using round ducting practical
and low air velocity achievable.

Vary primary air pressure for capacity control ?

AV primary air flow is

typically simple with

arying the plenum pressure
orifice plate “Iris” type
yields a non-linear capacity
response. Tight control
with variable plenum
dampers.
pressure is typically
impractical.

Vary primary air pressure for capacity control ?

Recommended CAV damper types

Iris Dampers –
(angled multi-leaf blades)

Pressure independent –
butterfly type

Iris Dampers

Damper “Tips”

ize dampers for flow and pressure drop.
• i.e. Do NOT oversize the damper by simply installing a nominal duct
diameter damper. Check range of flow control, step-down if required.

enturi – style dampers are typically only used with labs, and narrow-band
pressurization control.

heck for flow generated noise with larger pressure drops.
• Add duct silencers if necessary.

onsider VAV air valves for spaces with highly variable latent loads.
• Be aware of additional control requirements
• Consider “occupancy” type (i.e. 2-position) air valves for these spaces
in an effort to manage control costs.

Acoustics

atch for flow generated noise across Iris damper.

dd duct mounted silencers if required.

Balancing and confirmation

eams are considered a constant volume device. Apply a known plenum
static pressure, and the cross-sectional area of each nozzle sums to yield
the total primary air delivered by the beam. Adjust orifice ∆P for beams
of common pressure; - their nozzle determines the primary air flow rate.

ince the induction ratio is exceedingly difficult to field measure, the most
accurate means of determining the primary air delivery, is to rely on the
manufacturer’s plenum pressure vs. volume relationship, which is typically
measured with a precision orifice. Confirmation of zone flow rates can be
accomplished via a duct traverse at a node of common intersection.

low hoods cannot be used to determine total air flow into the space due
to the recirculation component of the room air.

Challenges

ominal duct size vs. ∆P across Iris dampers.

oning to minimize capital costs.

ight-time set-back.

imultaneous perimeter heating with core cooling.

ir-side free-cooling.

ew-point control.

Water-side control and measurement

Self-regulating thermal capacity

Example 1
(1365 Btuh) Room Temp = 75oF
Water temp = 61oF
Approach temp = 75oF-61oF
= 14oF
Capacity = X
(682 Btuh)
Room Temp = 68oF
Water Temp = 61oF
Approach temp = 68oF-61oF
= 7oF
Capacity = 1/2X

Modulating water flow

Turbulent
flow

Laminar
flow

Single circuit water flow Temperature controlled water
•Non-linear •Restricted to zone control
•Expensive •Expensive
•Maintenance issues? •Maintenance issues?

Challenges

ater-side free cooling

oning

hilled water reset by zone

alve authority
 (Ensure that the control valves are sized based on Cv, NOT
line size)

“Tips” for easier commissioning

se pressure independent flow regulating valves

everse-return piping can sometimes make life “easier” in each zone

pply venting “liberally”

ressure independent
water control valve

(Constant Flow
Rate)

Start-up
Sample start-up sequence

onfirm start-up and operating sequence with the: plans, specifications, and
consulting engineer.

onfirm primary air ducting is free of dirt and debris to prevent beam nozzle
clogging.

eal all duct leaks, and ensure all duct access ports are affixed to the duct to
achieve specified duct leakage rates.

lit protective film at the active beam discharge to allow primary air to enter the
space. Do NOT remove the protective film, until the work space is in an “as-

Start-up
Sample start-up sequence (cont’d)

o NOT operate the active beams for temporary heat without prior written
approval from the consulting engineer.

lose all operable windows, and ensure building exit doors are sealed to assist in
the envelope dehumidification.

ommission and operate the primary air handling unit for building envelope
dehumidification.

alance supply air ducting to each zone.

Start-up

nsure a clean environment within which the active beams will operate (i.e. no
gypsum dust or other construction contamination)

emove protective film from active beam units

nsure piping “mains” have been flushed and “leak-tested”, prior to being
connected to the beam coils

O NOT UNDER ANY CIRCUMSTANCES FLUSH THE PIPING SYSTEM
THROUGH THE BEAM MOUNTED COILS.

Start-up

onfirm that all air has been removed from the distribution piping. Deliver excess
water by increasing the pump flow, or by closing other zones to assist in the
removal of air from the system.

nce the building envelope dew point has been reached, slowly lower the
secondary chilled water temperature to the scheduled design value. Note that
dehumidifying the building envelope may require several days, or up to a week
initially, to completely dehumidify the space.

onfirm secondary water conditions regularly to ensure that it is properly filtered,
and appropriately inhibited.

Start-up
Shop drawings and schedules as a tool for commissioning

Sample space serviced by active beams
Child care classroom, California

Active Beam Commissioning Overview

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