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MBB box

When performance matters….

Secure, Flexible and Simple

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Background...

• An independent Swedish report shows generally low accuracy on flow-measurement of plenum boxes in the ventilation market

• Quotes from the report:• “For ceiling diffusers with plenum box we have found that the distance to disturbing

source often has larger impact for calculation of air flow than the suppliers indicates. Even the position of the damper often has influence but that is not mentioned in the suppliers instructions for calculations of air flow... We request that suppliers correct the majority of K-values and improve the documentation and labelling”.

• “If a diffuser has more K-values it provides substantially better opportunities to get correct measuring results”.

• This we had to take seriously

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Background...

Why plenum box?• Balance ventilation system

• Measure air flow

• Reduce noise

• Even distribution to diffusers

The box shall be;• Quiet

• Accurate

• Small

• Simple

• Readable

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Balancing principles...

1. Rotating• Must be perforated for noise

• “Only fine-tuning”

2. Sliding• Must be perforated for noise

• “Only fine-tuning”

3. Linear• Must be perforated for noise

• “Only fine-tuning”

4. Linear cone• “0”-100 % air flow

• Linear characteristics

• Low noise

Dotted Line = old MBA

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Measuring principles

1. Before the damper• Sensitive to bends or installation

• Poor in low flow range

2. Over the damper• Variable k-value

3. After the damper • More pressure drop

• Poor in low flow range

• Variable k-value for high accuracy

4. Over the diffuser• Not for high flow rate diffusers

• Variable k-value for high accuracy

• Different k-values for diffusers

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Air distribution principles...

1. Damper cone• Needs a certain width

• No extra equipment

2. Closed perforated plate• More pressure drop

• Needs a certain width

3. Open perforated plate.

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Secure...

High capacity and low sound even at high pressure

• CFD-, and laboratory tested• Completely unique damper solution• Smaller box

• Usable in systems with chilled beams.

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Secure...High capacity and low sound even at high pressure

• Capacity of NS19+MBB• Example:

Competitor 1 and 2can manage about 45l/son a 125mm connection.

• Lindab about 58 l/s.

Preconditions: 100Pa and sound power level 34dB(A)(Enquiry from main customer)

Competitor 1

Competitor 2

=

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OK

Cost material:Box MBA-125/160, 40 pcs.Damper, DRU 315, 4 pcs.Silencers, LRCA 315 1000, 4 pcs.Damper DRU 125, 4 x 5 pcs.Silencer SLCU 125 600, 4 x 5 pcs. = 20 pcs.Connection ducts dim 125, length 3 m, 40 pcs.Total: 42,100 SEK (netto)

Cost mounting:Total: 52 hours, approx. 18,000 SEK

Secure...Money saving

• A traditional system of 40 diffusers• Dampers and silencers • 38 dB(A)• Total cost 60 100 SEK

• Exchange MBA with MBB• 32 dB(A) • Similar cost

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Cost material:Box MBB-100/160, 40 pcs.Connection ducts dim 100, length 3 m, 40 pcs.Total: 24,500 SEK (netto)

Cost mounting:Total: 38 hours, approx. 13,300 SEK

Secure...Money saving

• Remove Silencers• Remove Dampers• 34 dB(A)• Total Cost 39 000 SEK

• Go down one size• + 7 pa – approx. 1,6 %

higher energy consumption• Still below 38 dB(A)• Total Cost 37 800 SEK

• Savings of appr. 37%.

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Flexible...

0-100% operational area

• Possible to have low flow with high pressure • 20 l/s, 100 Pa

LWA= 24 dB(A)• And high flow with

low noise• 76 l/s, 70 Pa

LWA=34 dB(A)

• With 125mm connection!!!!

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Flexible...

Viable for future applications

• The MBB box can cope with almost any future demands • Always possible to balance it to a lower flow • Together with e.g. LKP/LCP you make sure to have unique operating range all

the way down to zero also concerning air movements• Very high damping without generating a noise problem

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Simple...

Simplifying balancing

• Damper with readable k-values• Easy to reach and read the scale• K-values fixed to damper positions• K-values are independent of diffusers• Can be pre- and re-balanced (CADvent)• Steady high measuring pressure even

at low flow• Better adjustment characteristics

(No “Ketchup effect”)

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

0

10

20

30

40

50

60

Damper characteristics at pt = 50 Pa

MBB-125-200MBA-125-200

Stroke/Angle

q [

l/s]

50%

100%

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Simple...

Small dimensions

• Easy handling, mounting and cleaning• Smaller ducts because of larger capacity • Lower Carbon footprint

(Less material, less transports, less packaging material)

• Easy installing with Safe / Safe Click connection• Low building height• Insulation prevents sound generating from outlet

(Inlet diffuser increases sound otherwise)

Dimension Lindab Comp. 1 Comp. 2

100/125 Height 160 mm 180 mm 220 mm

100/125 Height 220 mm 240 mm 255 mm

100/125 Height 310 mm 340 mm 345 mm

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MBB boxWhen performance matters...

Secure• Low sound – high pressure• Less dampers and silencers –

still silent• Accurate measurement –

no problem with disturbingsources before the box

• Reliable measurement – variable k-values

Flexible• 0-100% dynamic

operational area• Low flow with high

pressure• High flow with low noise• Viable for future system

changes

Simple• Linear damper means

easy and quick balancing• Prebalancing is possible• Small dimensions – easy

to handle and install• Easy to clean

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Simplified construction…