The pros and cons of chilled beams

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1 The pros and cons of chilled beams Peter Clackett, Technical Director Skanska Rashleigh Weatherfoil William Booth, Operations Manager BSRIA

2 Agenda Registration Welcome & Introduction - Jo Harris, BSRIA 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 Networking Lunch Click on links above to access each presentation At the end of each presentation, click on link Back to Agenda

4 What, why, how many?

5 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

6 Chilled Beams What are they? 1. Passive No reliance on primary air supply. They work entirely on radiant convection. (Output 130 to 170 watts per linear metre)

7 Chilled Beams What are they? 2. Active These rely on primary air supply to provide the induction required for performance. (Output 850 to 1400 watts per linear metre)

8 Chilled Beams What are they? 3. Multi Service These are active beams with the additional components (smoke detectors, lighting, sprinklers etc.) (Output 850 to 1050 watts per linear metre)

9 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

10 How many?

13 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)

14 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

15 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

16 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

17 Market Data * Item Market ( M) Active Chilled Beams Fan Coils Variable Air Volume 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 Fan Coils Variable Air Volume * Data provided by WMI, BSRIA

18 2012 Market Data* 2012 Market Share ( M) Variable Air Volume, 5.3 Active Chilled Beams, 8.0 Variable Air Volume, 13, Market Share (units) Active Chilled Beams, 27,000 Fan Coils, 23.7 Fan Coils, 46, Unit Price Variable Air Volume, 393 Active Chilled Beams, 296 Fan Coils, 506 * Data provided by WMI, BSRIA

19 70% Market 2012 FCU Market Players (Ranked By Value) Ability Projects Diffusion Dunham Bush TEV limited Trox * Data provided by WMI, BSRIA

20 20% Market 80% Market 2012 ACB Market Players (Ranked By Value) Trox Frenger Systems (Lindab) Halton SAS international Krantz Swegon Flaktwoods LTI Advanced systems Technology (Keifer brand) Waterloo Air products Others * Data provided by WMI, BSRIA

21 Back to Agenda

22 Description and application

23 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

24 Active Chilled Beams - Considerations 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

25 Active Chilled Beams - Considerations Heating application requires careful design It can be counter intuitive Full mock-up of partial areas is the best solution to understand the product

26 Video not available in pdf. format

27 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

28 Active Chilled Beams - Advantages 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

29 Active Chilled Beams - Advantages 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

30 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

31 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

32 Back to Agenda

33 Performance testing

34 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

35 Schematic of test chamber

36 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

37 Performance Testing BS EN 15116:2008 Temperature difference ΔΘ = Θ r θ w Θ r = reference air temperature Θ w = mean cooling water temperature q p = primary air flow rate 3 steady state conditions at ΔΘ = 6, 8 and 10K with constant q p Repeat at ΔΘ = 8K nominal with q p at 80% and 120% to determine influence of primary air on thermal performance Repeat all five at half the nominal water flow rate

38 Performance Testing BS EN 15116:2008 Performance follows the form of P w = P k * ΔΘ m Where P w is waterside cooling capacity P k is specific cooling capacity m is an exponent Alternatively, P k = P w / ΔΘ m Also, P k = A * q p n A is a characteristic constant n is an exponent

39 Example Results

40 Example Results

41 Example Results

42 Water side duty ( W) Water side duty (W) P w (const q p ) Mean Temperature Difference (K) y = x R² = 1 Pw (const qp) Power (Pw (const qp)) P w (var q p ) Primary airflow rate (q p ) (l.s -1 ) y = x R² = Pw (var qp) Power (Pw (var qp))

43 Example graph of Capacity against temperature difference for three water flowrates

44 Same as previous showing passing through zero

45 Different beam same graph shape

46 Airflow vs. flowrate of air

47 Water side pressure drop vs. flowrate

48 Performance Testing Performance follows the form of P k = P w / ΔΘ m P k = A * q p n Report the nominal cooling capacity P N (at ΔΘ n = 8K) Optionally, cooling capacity as fn(globet- Θ w ) or fn(roomt - Θ w ) Selection guides and tables will include throw, noise figures, water and air side pressure drops as well as nozzle selections, heating coil options, etc..

49 Ball Park Numbers mm Waterside Cooling 0.02 to 0.10 l/s C supply with 1-3K rise Waterside Heating ( W/m) 0.01 to 0.04 l/s C inlet with drop of 5 to 15K Airside Cooling/Induction l/s primary air at 18 C for roomt 24 C

50 Back to Agenda

51 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

53 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 Client s ventilation system AHU Ceiling void Glass window Viewing chamber Floor tiles/carpet Floor void Chamber wall Adjacent chamber Adjustable walls Control room Insulated floor ( 400 mm)

54 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.

55 Validation process Room air movement Gas tracer tests Salt tests Supply Chamber Ceiling Ceiling void Smoke tests Fans/Air conditioning system Ceiling tiles Wall Floor tiles Adjacent chamber CFD Floor extract Back passage Extract Floor void Control room Airtightness Mock-up construction Design

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

56 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

57 Offices Data centres Libraries Chilled beams Cold cabinets Hospitals

58 Real site vs mock-up

59 Job A

60 Job A

61 Job A

62 Animation Animation not available in pdf. format

63 Smoke test Video not available in pdf. format

64 Job B

65 Example of discharge profile

66 Job C

67 Example of ductwork and ceiling

68 Calc Induced Flow (l/s) Example of Pressure test Full pressure test - Beam 1 type 2 (16 Sep 05) y = x R 2 = y = x R 2 = Primary Flow (l/s) Calc Ind Flow Ratio Linear (Calc Ind Flow) Linear (Ratio)

69 Example of average parameters A PARAMETER REQUESTED VALUE AVERAGE DURING TEST SUPPLIED VALUE Water supply temperature ( C) Water return temperature ( C) To be recorded 15.9 Water flow rate (l.s -1 per beam) Water flow rate (l.s -1 all beams) N/A Cooling duty (10 beams) (W) N/A 2958 Fresh air supply temperature at point of entry to the test rig ( C) Extract temperature ( C) To be recorded 23.5 Air flow rate (l.s -1 ) Fresh air cooling duty (W) N/A 583 Total cooling (W) N/A 3541 Electrical load (W) Start End Solar load simulated with wall mounted heated mats Occupancy (6 DIN Men simulating 7.5 people) Small power gain Lighting gain Total electrical load Total electrical load (Average) Imbalance (W) 169

70 Example of parameters PARAMETER VALUE Fresh air supply volume 60 l.s -1 Fresh air supply temperature 19.0 C Beam chilled water supply l.s -1 volume for perimeter test Beam chilled water supply l.s -1 volume for core test Chilled water supply 14.0 C temperature Illuminance As produced by integral lighting system

71 Example of average parameters B PARAMETER AVERAGE SUPPLIED VALUE REQUESTED VALUE Fresh air flowrate 64.1 l.s l.s -1 Extract flowrate 62.6 l.s 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 W 600 W standard DIN men) Core small power gain (simulated with 1.69 kw kw 4 standard PCs and 7 floor heat mats) Lighting gain 905 W As produced by integral lighting system Total heating gain (perimeter, core and lighting) kw kw plus lighting gain Chilled beam water flow temperature 13.9 C 14 C Chilled beam water return 16.4 C N/A temperature Chilled beam water flowrate 0.28 l.s l.s -1

72 Parameter Average cooling during Test 3 (kw) Chilled beam cooling effect 2.93 Air cooling effect 0.34 TOTAL COOLING 3.27 kw

73 Back to Agenda

74 Ugly Duckling or Hidden Swan?

75 Chilled Beams - Advantages Cheap to Buy and Maintain Simple principals Simple Controls Give a well conditioned space Very adaptable Quiet Energy Efficient

76 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

77 Questions and answers

78 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

79 Back to Agenda

ANSI/ASHRAE STANDARD , METHODS OF TESTING CHILLED BEAMS

ANSI/ASHRAE STANDARD , METHODS OF TESTING CHILLED BEAMS ANSI/ASHRAE STANDARD 200-2015, METHODS OF TESTING CHILLED BEAMS NEMIC 2017 Agenda 1. Foreword 2. Purpose & Scope 3. Definitions 4. Instrumentation & Facilities 5. Test Methods 6. Reporting 7. Normative