Chilled Beams Event

The pros and

cons of chilled

beams

Peter Clackett, Technical Director

Skanska Rashleigh Weatherfoil

William Booth, Operations Manager

BSRIA

Agenda

09.30 Registration

10.00 Welcome & Introduction - Jo Harris, BSRIA

10.10 What, Why and How - Peter Clackett, Skanska

Description and Application - Peter Clackett, Skanska

Performance testing - William Booth, BSRIA

Comfort break/coffee

Performance testing continued - William Booth, BSRIA

The good, the bad and the ugly -

Peter Clackett, Skanska and William Booth, BSRIA

Q&A - Chaired by Jo Harris, BSRIA

12.40 Networking Lunch

Click on links above to access each presentation

At the end of each presentation, click on link Back to Agenda

What, why, how many ?

Chilled Beams – What are they?

They are a cooling device

They are different from chilled ceilings – These rely

solely on radiant cooling (Output 50 to 55 watts per

square metre)

They are an alternative to both Fan Coil Units and

VAV systems

There are three kinds of chilled beams

Active Chilled Beams can also be used for heating


1. Passive – No reliance on primary air supply. They

work entirely on radiant convection. (Output 130 to

170 watts per linear metre)


2. Active – These rely on primary air supply to provide

the induction required for performance. (Output 850

to 1400 watts per linear metre)


3. Multi Service – These are active beams with the

additional components (smoke detectors, lighting,

sprinklers etc.) (Output 850 to 1050 watts per linear

metre)

Chilled Beams – The History

Chilled Beams were developed in Norway in 1975

Originally used in Scandinavia

Introduced to UK in 1990’s

Now used world wide

Device of choice for some Clients

How many?

ACB UK Market Data

Provided by BSRIA’s Worldwide Market Intelligence

(WMI) Group

– Data comes from the HEVAC study

– Annual collection of a/c product sales

– Managed by BSRIA for a number of years with

HEVAC/FETA’s endorsement

All data to be published in the UK Air conditioning

study next month – buy from WMI

Author David Garwood (available over lunch)

Market For Chilled Beams & Ceilings*

UK market reduced over last couple of years

– Many major projects were shelved or put on hold

Leading suppliers now seeing signs of improvement

Some major projects now moving forward

2012 sales were for universities, hospitals and labs

plus a few offices and police stations

* Data provided

by WMI, BSRIA

UK Fan Coil Market*

Highly engineered product in UK market

But ….. Highly price driven

Customers of fan coils look at :

– First – price

– Second – thermal performance

– Third – acoustic performance

* Data provided

by WMI, BSRIA

Chilled Beams vs Fan Coil Units

Active chilled beams main substitute product for FCUs

Conversely, ACB players fighting back against threat of

FCU through marketing:

– Demonstrating how ACB can be a suitable replacement for

FCU

– Placing emphasis on:

• Energy efficiencies

• Long life expectancy

• Low maintenance

• Occupant comfort * Data provided

by WMI, BSRIA

Market Data 2010-2012*

* Data provided

by WMI, BSRIA

Item 2010 2011 2012

Market (£M) Active Chilled Beams 9.7 9.9 8.0

Fan Coils 26.6 27.1 23.7

Variable Air Volume 2.3 6.7 5.3

Volume ( Units) Active Chilled Beams 34,500 33,400 27,000

Fan Coils 51,500 54,000 46,800

Variable Air Volume 5,500 13,300 13,500

Unit price Active Chilled Beams £281 £298 £296

Fan Coils £517 £502 £506

Variable Air Volume £418 £504 £393

2012 Market Data*

Active Chilled Beams, 8.0

Fan Coils, 23.7

Variable Air Volume, 5.3

2012 Market Share (£M)

Active Chilled Beams, 27,000

Fan Coils, 46,800

Variable Air Volume, 13,500

2012 Market Share (units)

Active Chilled Beams, £296

Fan Coils, £506

Variable Air Volume, £393

2012 Unit Price

* Data provided

by WMI, BSRIA

2012

Ability ProjectsDiffusionDunham BushTEV limitedTrox

FCU Market Players (Ranked By Value)7

0%

Mar

ket

* Data provided

by WMI, BSRIA

2012

TroxFrenger Systems (Lindab)HaltonSAS internationalKrantz

Swegon

Flaktwoods

LTI Advanced systems Technology (Keifer brand)

Waterloo Air products

Others

80

% M

arke

t2

0%

Mar

ket

ACB Market Players (Ranked By Value)

* Data provided

by WMI, BSRIA

Back to Agenda

Description and application

Active Chilled Beams - Considerations

Still requires central bulkhead or similar for services

(Supply Duct, Extract Duct, Chilled Water Pipework,

Controls etc.)

Careful control of primary supply air temperature

required to prevent perception of “cold draughts”

Chilled water temperature needs accurate control


Performance of the whole space needs to be

evaluated

The air patterns are very hard to predict

Air distribution throughout the space is load

dependent

Computer modelling does not give the true air

movement answers

You MUST understand the product, how it works and

how it integrates to its environment


Heating application requires careful design – It can

be counter intuitive

Full “mock-up” of partial areas is the best solution to

understand the product

Video not available in pdf. format

Active Chilled Beams - Advantages

Cheaper to buy

Low Maintenance

One “Fix” device – Does not require secondary

ductwork/Grilles etc.

Only require simple controls – On/Off is adequate for

cooling

Variable Self Limiting Output

No condensate drainage required


Supply conditioned air to the space

Large induction ratios

Fully mixes the air within the space

Very slow air velocities within the occupied zone

Multi service beams allows ancillary services to be

concealed


Works well when combined with other cooling

sources – Requires full scale mock-up testing to

ensure that they do not interact

Very quiet product

Can be visually pleasing

Active Chilled Beams - Disadvantages

Not liked by letting agents – Not flexible enough

No energy allowances under Building Regs. (FCU’s

allowed 0.6w/(l/s) - FAVAV allowed 1.2w/(l/s))

Normally requires higher system static pressures

Airflow may be greater than required for occupancy

Active Chilled Beams - Disadvantages

Poor chilled water temperature control can lead to

“indoor rain”

May require sound masking (pink noise) to maintain

privacy levels

Requires careful co-ordination to get the solution right

Back to Agenda

Performance testing

ACB Definitions

Reference temperature: return air onto beam (usually

underside in active beams)

Mean water temperature: average of water into and

out of beam

Difference gives indication of cooling potential: no

difference means no cooling should happen

BS EN 15116:2008 “Ventilation in buildings. Chilled

beams. Testing and rating of active chilled beams”

Schematic of test chamber

Performance Testing BS EN 15116:2008

Internal heat supply method

– Heat sources within chamber (DIN men)

External heat supply method

– Heated walls (same concept as radiator test room)

General principle of a calorimeter with steady state

boundary conditions and 60 min steady state data


Temperature difference

ΔΘ = Θr – θw

Θr = reference air temperature

Θw = mean cooling water temperature

qp = primary air flow rate

3 steady state conditions at ΔΘ = 6, 8 and 10K with constant qp

Repeat at ΔΘ = 8K nominal with qp at 80% and 120% to determine

influence of primary air on thermal performance

Repeat all five at half the nominal water flow rate


Performance follows the form of

Pw = Pk * ΔΘm

Where

Pw is waterside cooling capacity

Pk is specific cooling capacity

m is an exponent

Alternatively, Pk = Pw / ΔΘm

Also, Pk = A * qpn

A is a characteristic constant

n is an exponent

Example Results

Example Results

Example Results

y = 77.233x1.0598

R² = 1

0

100

200

300

400

500

600

700

800

900

1000

0 5 10 15

Wat

er

sid

e d

uty

(W

)

Mean Temperature Difference (K)

Pw (const qp)

Pw (const qp)

Power (Pw (const qp))

y = 182677x-1.394

R² = 0.9777

0

100

200

300

400

500

600

700

800

900

1000

0 20 40 60 80

Wat

er

sid

e d

uty

( W

)

Primary airflow rate (qp) (l.s-1)

Pw (var qp)

Pw (var qp)

Power (Pw (var qp))

Example graph of Capacity against

temperature difference for three water

flowrates

Same as previous showing passing through

zero

Different beam same graph shape

Airflow vs. flowrate of air

Water side pressure drop vs. flowrate

Performance Testing Performance follows the form of

Pk = Pw / ΔΘm

Pk = A * qpn

Report the nominal cooling capacity PN (at ΔΘn = 8K)

Optionally, cooling capacity as fn(globeT- Θw) or

fn(roomT - Θw)

Selection guides and tables will include throw, noise

figures, water and air side pressure drops as well as

nozzle selections, heating coil options, etc..

Ball Park Numbers 1200-1500mm

Waterside Cooling

– 0.02 to 0.10 l/s

– 14-16°C supply with 1-3K rise

Waterside Heating (100-300 W/m)

– 0.01 to 0.04 l/s

– 35-45°C inlet with drop of 5 to 15K

Airside Cooling/Induction

– 10-60 l/s primary air at 18°C for roomT 24°C

Back to Agenda

System performance testing

Physical modelling

Predicting and measuring real life

situations

Achieving the correct results first

time

Prove beforehand that the

systems and products will meet

the necessary specifications

Water supply (from chiller)

Conditioned air

Floor tiles/carpet

Client’s

ventilation system

Floor void

Ceiling void

AHU

Glass window

Viewing chamber

Adjustable walls

Chamber wall

Insulated floor

( 400 mm) Control room

Adjacent chamber

Physical modelling

Constructing a full size

representation of the proposed

design for a specific part of a

building interior.

– Full simulation of external

conditions

– Internal loads

– Comprising lighting

– Small power and people

– Room furnishing and office

equipment layout

– Fully working HVAC system.

Chamber Ceiling

Floor void

Ceiling tiles

Floor tiles

Ceiling void

Wall

Extract

Supply

Fans/Air conditioning

system

Control room

Adjacent

chamber

Back passage

Floor extract

Smoke tests

Airtightness

Gas tracer

tests Salt tests

Design Mock-up

construction

Room air

movement

Validation process

CFD

Full size mock-ups

Mock-ups of any ventilation system;

chilled beam configuration, offices,

hospital rooms, cold cabinet testing

Thermal comfort analysis

Temperature and humidity readings

Airtightness tests

Heat load simulation (Small load,

occupancy, solar load)

Anemometry readings ( air speed

and temperatures)

Gas tracer tests

Special components commissioning

(pressure stabilisers, ventilation

grilles, floor grilles)

Thermal imaging

Smoke tests

Offices Data centres Libraries

Hospitals Chilled beams Cold cabinets

Real site vs mock-up

Job A

Job A

Job A

Animation

Animation not available in pdf. format

Smoke test

Video not available in pdf. format

Job B

Example of discharge profile

Job C

Example of ductwork and ceiling

Example of Pressure test

Full pressure test - Beam 1 type 2 (16 Sep 05)

y = 2.2863x - 9.3206

R2 = 0.9933

y = 0.0366x + 1.0705

R2 = 0.8431

0.00

5.00

10.00

15.00

20.00

25.00

30.00

35.00

40.00

45.00

50.00

0.00 5.00 10.00 15.00 20.00 25.00 30.00

Primary Flow (l/s)

Ca

lc I

nd

uc

ed

Flo

w (

l/s

)

0.00

0.50

1.00

1.50

2.00

2.50

Calc Ind Flow Ratio Linear (Calc Ind Flow) Linear (Ratio)

Example of average parameters A

PARAMETER REQUESTED

VALUE

AVERAGE

DURING TEST

SUPPLIED

VALUE

Water supply temperature (C) 14.0 13.9

Water return temperature (C) To be recorded 15.9

Water flow rate (l.s-1 per beam) 0.039 0.039

Water flow rate (l.s-1all beams) N/A 0.353

Cooling duty (10 beams) (W) N/A 2958

Fresh air supply temperature –

at point of entry to the test rig

(C)

18.0 18.1

Extract temperature (C) To be recorded 23.5

Air flow rate (l.s-1) 90 97

Fresh air cooling duty (W) N/A 583

Total cooling (W) N/A 3541

Electrical load (W) Start End

Solar load – simulated with 15

wall mounted heated mats 1416 1418 1440

Occupancy (6 DIN Men

simulating 7.5 people) 675 685 698

Small power gain 844 830 835

Lighting gain 405 419 419

Total electrical load 3340 3352 3392

Total electrical load (Average) 3340 3372

Imbalance (W) 169

Example of parameters

PARAMETER VALUE

Fresh air supply volume 60 l.s-1

Fresh air supply temperature 19.0 °C

Beam chilled water supply

volume for perimeter test

0.226 l.s-1

Beam chilled water supply

volume for core test

0.274 l.s-1

Chilled water supply

temperature

14.0 °C

Illuminance As produced by integral

lighting system

Example of average parameters B

PARAMETER AVERAGE

SUPPLIED

VALUE

REQUESTED

VALUE

Fresh air flowrate 64.1 l.s-1 60 l.s-1

Extract flowrate 62.6 l.s-1 60 l.s-1

Fresh air supply temperature 19.0 °C 19.0 °C

Extract temperature 23.4 °C N/A

Altrium roof load emitted into room

(simulated with 3 wall mounted heat

mats)

510 W 525 W

Core people gain (simulated with 6

standard DIN men)

600 W 600 W

Core small power gain (simulated with

4 standard PCs and 7 floor heat mats)

1.69 kW 1.821 kW

Lighting gain 905 W As produced by

integral lighting

system

Total heating gain (perimeter, core and

lighting)

3.705 kW 2.946 kW plus

lighting gain

Chilled beam water flow temperature 13.9 °C 14 °C

Chilled beam water return

temperature

16.4 °C N/A

Chilled beam water flowrate 0.28 l.s-1 0.274 l.s-1

Parameter Average cooling during Test

3 (kW)

Chilled beam cooling effect 2.93

Air cooling effect 0.34

TOTAL COOLING 3.27 kW

Back to Agenda

Ugly Duckling…

or Hidden Swan?

Chilled Beams - Advantages

Cheap to Buy and Maintain

Simple principals

Simple Controls

Give a well conditioned space

Very adaptable

Quiet

Energy Efficient

Chilled Beams - Disadvantages

Not always popular

Lack of application knowledge can

restrict use

Low noise may be an issue

Integration into environment may not be

as simple as it seems - Can be hard to

get right

Questions and answers

Q&A Session

Adaptive temperature theory

Turbulent water flow

Uneven load distribution

Load location fighting the beam

Windows impinging on active beam lengths

Control strategy

Back to Agenda

Documents

Chilled Beams Event