2. Back to Basics Engineering Seminar Thursday, 10 November 2011

3. About Us Crofton Design consulting engineers providing structural, mechanical, electrical and civil engineering design for the construction industry. Our commitment to innovation, sustainability and energy efficient engineering sets us apart in our field − providing our clients with the right solution for their needs.

4. Agenda  About Us  Introduction  The Design Process  Active / Passive Buildings  Improved Common Approach  Standard Part L Compliant  High Energy Buildings  Conclusion

5. Introduction Why go ‘Back to Basics?’  Building Services  20% - 30% capital cost building  50% running cost  Design Process  Building Categories

6. Design Process InceptionUnderstanding the brief Establish key features Energy Heating CoolingVentilation Process Special

7. Design Process External factor - Climate

8. Design Process Improved Increasing Energy Use… Active Passive Part L Compliant High Energy Building Categories

9. Design Process Established building key features Modelling Compliant?Non Compliant? Service concept established Review

10. Good Practice Guidelines – All Building Types Micro Climate Rules of Thumb  Analyse the climate even in the UK!  UK winter temperatures can vary by as much as 2.6˚c:  London, 3.3˚C, Cardiff – 5.9˚C  Mean wind speed can also vary dramatically; London 3.3 m/s, Cardiff 5.1 m/s  Acknowledge the heat island effect  City temperatures can be higher by up to 8˚C  City building have move effective absorption of solar radiation and less effective long-wave relative cooling e.g. get hot quickly, take longer to cool  City wind speeds are much lower then the mean  Cities have drier landscapes - vegetation can be less effective in passive design  Know your wind direction (generally SW in UK)  Use dynamic simulation to model the building and take time to analyse the results as a team

11. Good Practice Guidelines – All Building Types Thermal Storage/Mass Rules of Thumb  Isolate mass from external air temperature  Locate insulation within the building envelope  ‘Couple’ the thermal mass to the heat source e.g. try to keep it exposed  Wall should be a minimum of 100mm thick  Thicknesses greater then 200mm have little effect other then increasing the overall decrement factor  Know Y-Value and decrement factors as well as U-Values Wall TypeTypical Y- Value Typical Decrement (hrs) Timber frame1.07.5 Masonry Cavity Wall (light weight block) 2.6510.65 Masonry Cavity Wall (heavy weight block) 5.0410.67

12. Good Practice Guidelines – All Building Types  Requirement for Hot Water  No requirement = no installation  Examples of use: Kitchens, sports centres, advanced heating installations, nursing homes  Output - 450kWh/PA/m2 up to 800kWh/PA/m2 dependent upon type  Availability of Roof/Mount Space  Optimal mounting aspect between South East and South West  Thermal Storage & Pumping  Thermal storage vessels required. The overall volume required will of course depend up application and system capacity. Commonly around 200L dedicated thermal store per 800kWh/PA/m2 Solar Rules of Thumb

13. Good Practice Guidelines – All Building Types Orientation Rules of Thumb  South Facing Facades  Provide brise soliel to south facades to limit heat-gain from midday sun  West Facing Facades  Provide vertical external protection if possible/aesthetically viable to limit heat gain from low altitude afternoon sun  Passive Solar Design  Maximise solar gains in winter  Needs to be controllable in summer  Maximise Natural Daylight  Minimise use of artificial lighting during the day

14. Basic Building Types – Active/Passive Active Principles  Three core concepts:  Energy  Indoor Climate  Environment

15. Basic Building Types – Active/Passive Passive Principles  Super Insulation  Limited Heating  High Volume to External Surface Ratio  Advanced window technology (triple glazed)  High air tightness (less then 1m3/hr/m2 @ 50 pa)  Natural ventilation or mechanical with heat recovery  Elimination of cold bridges  Some use of passive solar gain (use with caution)  Some use of thermal mass (use with caution)  Possible renewable energy  Solar shading  Night cooling

16. Active/Passive Building Features

17. Building Modelling Improved Building Principles – 1 of 2  Reduced Carbon Emissions  Driven by client policy or planning requirement - typical 10%-20% reduction  Moderate air tightness  about 5m3/hr/m2 @ 50pa  Heating  Utilising air or ground source heat pumps or other low carbon source  Application of Mechanical Heat Recovery Ventilation  Recoup energy from ventilation air

18. Building Modelling  Open-able windows to assist with Summer Time temperature control  Consideration of the following to limit summer heat gains:  Orientation  Glazing characteristics  Solar protection  Use of night time cooling strategies Improved Building Principles – 2 of 2 kWh/m 2 50 CO2/m 2 25

19. System Option Appraisal - Improved Building Under-floor Heating with Mechanical Ventilation Indicative cross-section for Under floor Heating + MHVR  Key Considerations:  Suitable for well insulated buildings  Option for use of low grade heat, e.g. heat pumps or optimum condensing boilers  MHVR’s commonly used in conjunction. Benefit from heat recovery on ventilation.  High density occupied space with natural ventilation without drafts. Not suitable as heat output inadequate  Pipe distribution manifolds needed to deal with zone areas. Access required

20. Building Modelling Part L Compliant Building Principles – 1 of 2  Maximum Carbon Emissions allowable under building regulations  Air tightness about 5m3/hr/m2 @ 50 pa  usually required to meeting Part L energy criteria  Heating Utilising condensing boiler plant  U Values for glazing and fabric adjusted to achieve compliance

21. Building Modelling  Minimum application of Mechanical Ventilation to serve internal spaces  Open-able windows to assist with Summer Time temperature control and general ventilation  Basic measures to limit summer heat gains  Use of night time cooling strategies  May be possible employing stack effect Part L Compliant Building Principles – 2 of 2 kWh/m 2 90 CO2/m 2 40

22. System Option Appraisal - Part L Compliant Building Radiator Heating System Indicative cross-section for Radiator Heating  Key Considerations  Generally naturally ventilated building or limited mechanical ventilation for occupancy  Wall space used for Radiators  Coordination with electrical installation

23. Building Modelling High Energy Principles – 1 of 2  Air tightness about 5m3/hr/m2 @ 50 pa  Usually required to meeting Part L energy criteria  Cooling loads requiring mechanical cooling driven by:  Occupancy  Equipment  Process  Function  Solar / Fabric gains.  Heating via harmonised heating / cooling system

24. Building Modelling  Heating to ancillary areas may be simple with no cooling  U Values for glazing and fabric adjusted to achieve compliance  Application of Mechanical Heat Recovery Ventilation  Recoup heating and cooling energy in the ventilation air  Usually windows intended to be closed to limit ventilation heat losses and gains  Consideration of orientation  Measures to limit summer heat gains High Energy Principles – 2 of 2 kWh/m 2 100 + CO2/m 2 50 +

25. High Energy Historic Development – Typical Office Basic heating & ventilation

26. High Energy Historic Development – Typical Office Basic heating & ventilation with tempered air

27. High Energy Historic Development – Typical Office Heating & cooling from central plant with wasteful heat

28. High Energy Historic Development – Typical Office Hot duct / cold duct mixing plant

29. High Energy Historic Development – Typical Office Variable air volume

30. High Energy Historic Development – Typical Office Fresh air only

31. System Option Appraisal Fan Coil Unit (FCU) System Figure 1 - Indicative cross-section for FCU system Other key considerations  FCU comprise of htg, cooling coil, filter & supply fan  Ventilation supply is by means of centralised air handling units (AHU’s)  Density one per 27-36m2 in Façade zone  Density one per 60-90m2 in Internal zone

32. System Option Appraisal Variable Refrigerant Volume (VRV) Figure 2 - Indicative cross-section for VRV system Other key considerations  Installation similar to an FCU system  VRV comprise of 2-3 pipe refrigerant distribution system, coil, filter & supply fan  Ventilation supply is by means of centralised air handling units (AHU’s)  Density one per 27-36m2 in Façade zone  Density one per 60-90m2 in Internal zone

33. System Option Appraisal Variable Air Volume (VAV) Figure 3 - Indicative cross-section for VAV system  Key Considerations  VAV comprise LPHW Htg or Electric Heater Battery & filter  Control in groups or individually  Ventilation supply is by means of centralised air handling units (AHU’s)  Density one per 27-36m2 in Façade zone  Density one per 60-90m2 in Internal zone  Void/space requirements as shown

34. System Option Appraisal Chilled Beam Figure 4 - Indicative cross-section for Chilled Beam system  Key Considerations  Chilled Beams comprise heating & cooling coil  Multi Service integration of light fittings, fire alarm, public address etc. possible  Control in groups or individually  Ventilation supply is by means of centralised air handling units (AHU’s)  Exposed or recessed ceiling options available  Density one per 21-31m²  Void/space requirements as shown

35. System Option Appraisal Displacement Ventilation Figure 5 - Indicative cross-section for Displacement Ventilation system  Key Considerations  Floor void used as plenum, air cooled to 3-4˚C below room temperature  Heating provided by perimeter convectors.  Control limited  Ventilation supply is by means of centralised air handling units (AHU’s)  Allow exposed ceiling  Void/space requirements as shown

36. System Option Appraisal Load/Output Summary

37. Cost Appraisal  Comparable capital costs of different AC systems based upon a benchmark figure for FCUs of 150 £/m²  Costs exclude ceilings and builder’s work in connection. Capital Cost Summary

38. Cost Appraisal Operating Cost Summary  Comparable operating costs of different AC systems  Figures comprise maintenance and energy costs; the latter being based upon unit gas and electricity rates of 1.0 p/kWh and 5.5 p/kWh respectively

39. Conclusion  Why go ‘Back to Basics?’  Establish building characteristics  Identify key services features  Modelling = Iterative process  Compliant services solution

40. Any Questions?