morgan sindall operational energy assessment.pptx

operational energy

1. EFSA School Approach - Building Services

2. 6 WELCOME AGENDA CBDM BB 101 OVERHEATING PART ‘L’ BUILDING SERVICES

3. CBDM DAYLIGHT

4. 6 CBDM DAYLIGHT DAYLIGHT FACTORS - SKIES

5. 6 CBDM DAYLIGHT DAYLIGHT FACTOR TO CBDM Standard Overcast sky Empirical data 30yrs

6. 6 CBDM DAYLIGHT METRICS CBDM The whole purpose of good daylight is to improve the internal environment and ultimately stimulate learning and well being. It is also to lower energy dependency from artificial lighting. It is not so that buildings can be made cheaper and easier. Although if this is an outcome at the same time then even better. It should be noted that single side glazed deep rooms are not good for daylight penetration and that deep rooms should have two sided glazing. This allows a more uniform distribution of daylight and that would be better for the occupants and would reduce the probability of blinds being pulled down and lights being switched on. It is important to realise that CBDM calculations were not intended to be a verification tool but a design tool. They tell you what will be achieved with the input parameters. Many iterations take time and will show that building designs are hard to get to pass. The calculations should not be overlooked and should be performed at the earliest massing stage as they affect the elevations and room widths, heights, reflectances and depth. If performed too late then it may not be possible to make structural design changes and the EFSA may not grant funding if the building is a school. (Do not accept rules of thumb without full calculation before planning stage.) CBDM is relevant to any building however the EFSA have adopted the method. The two main metrics are called UDI and sDA shown right. Illuminance calculations are taken at a set of gridpoints (250 to 500mm apart) across the working plane. The calculations are performed every 15min of every day of the year between 08:30 and 16:00 hrs. So there are a lot of results at each grid point. At each point sometimes the light level will be <100 lux, sometimes >3000 lux but for 80% of the time we want the level to be between 100 and 3000 lux. The percentage that this range is achieved at each grid point is recorded. Then for UDI only, these results are averaged and that average must also be >80%. If windows are too big then there might be too much light and the UDI can fail. The sDA is really a measure of uniformity. It asks for there to be at least 300 lux at more than half the grid points for more than 50% of the time. It is not an average because we need to know what percentage of the working plane passes. We want that to be 50% of the working plane. Deep single lit classrooms will clearly struggle to pass here because it is hard to get enough daylight to the rear of the room unless ceiling heights are increased which comes at a cost. The two main metrics of CBDM Useful Daylight Index (80%) UDI-s : < 100 lx UDI-a : 100 to 3000 lx UDI-e : > 3000 lx Spatial Daylight Autonomy (50%) sDA : 300 lux 50% of time 50% of w/p

7. 6 CBDM DAYLIGHT METRICS UDI in more detail (Useful Daylight Index) Lets break down the metrics. UDI has 3 components UDI-s , UDI-a and UDI-e UDI-s UDI-s upplementary The light level is <100 lux at the grid point Clearly artificial lighting is needed to supplement. UDI-a UDI-a cceptable The light level is between the range 100 to 3000 lux This should be >80% at each point ideally. Some artificial light will be needed when the illuminance is lower than the target. UDI-e UDI-e xcessive The light level is >3000 lux at the grid point Here there is too much light and blinds might be unavoidable. 80% The criteria is for the UDI-a to be 80% (All the UDI values at each point are averaged. The average should be >80%) sDA in more detail (Spatial Daylight Autonomy) Lets break down the metric. sDA spatialDA The amount of the working plane that receives a target light level for a set time percentage of the year. For EFSA this is 300lux for 50% of the working plane for 50% of the period. 50% The criteria is for the sDA to be 50% (50% of the working plane has an illuminane of at least 300 lux for half of the time) NOTE: Improving one metric can make the other fail !

8. CBDM DAYLIGHT METRICS EFSA Calculation compliance details CBDM is not like daylight factors due to climate weather files. Therefore other factors are vital such as orientation, time of day and location etc There are strict compliance criteria and the CBDM report we provide should show that we have complied. It can take a very long time for the calculations so it is important to get it right first time. You cannot assume similar rooms will pass and rules of thumb will not suffice. Time period Calculations are made every 15min of every day for the full year. The time period is 08:30 to 16:00 Calculation grid The calculation grid is between 250mm and 500mm A border zone can be excluded around the perimeter wall but this is a maximum of 500mm from the wall. Working plane The working plane height must be taken relevant to the task. Classrooms are 550mm for primary and 700mm for secondary Weather file There are 5qty EPW weather files that must be used. Of the 5, the nearest to the school is chosen. Orientation Orientation is critical to CBDM. Exact north must be set as well as the building site position. i.e. 5° difference can affect the pass fail. Reflection Room reflection values must be reduced by 10% allowing for room surface maintenance factor (RSMF). The wall reflectance is averaged, allowing for 20% posters on the walls at 0.2 reflectance. Windows Window transmission must be reduced by 5% to allow for dirt. Frames should be modelled and not just an allowance frame factor % if possible. Sills, wall thickness etc should be modelled. Shading & obstructions Any external object that causes shading whatsoever needs considering. This could be significant trees, other buildings and the projects building itself (could be L shape and self occluding).

9. CBDM DAYLIGHT METRICS 3.3m 8m 7m 1.8m 2m 30 % glazed

10. CBDM DAYLIGHT METRICS Same rooms Obstructed Now Fails

11. REFLECTANCES Ceiling 80%x0.9% =0.72 Wall 70%x0.8 + 20%x0.2 = 60% 60%x0.9 =54% result Floor =0.28 CBDM DAYLIGHT Glass 5% dirt 0.7x0.95 =0.67

12. CBDM DAYLIGHT METRICS Revit Early trials Iterative Shading Glare

13. CBDM DAYLIGHT METRICS 80% :L1 : sDA,UDI 75% :L2 : UDI 60% :L3 : UDI

14. CBDM DAYLIGHT TIPS Classrooms and offices are L1 : wider than deep Locate rooms likely to fail in the corners or areas affected by shading Windows as high head height as possible No rule of thumb : quick revit calculation May need high ceilings 3.2m. Suspended ceilings at 2.7m = shallower rooms

15. DAYLIGHT vs OVER HEAT vs PART ‘L’ BALANCE Solution Over heating Daylight Part L M ech E lec L ight

16. OVERHEATING

17. OVERHEATING REGULATIONS BUILDING BULLETIN BB101

18. OVERHEATING OLD REGULATIONS Single threshold temperature No more than 120 hrs above 28°C Internal not to exceed external by more than 5°C Max 32°C

19. OVERHEATING NEW REGULATIONS 18°C feels warm after cold winter 18°C feels cold after warm summer

20. OVERHEATING ADAPTIVE THERMAL COMFORT (CIBSE TM52) DURATION SEVERITY LIMIT 32 Hours ‘6X’ in a day Internal not to exceed external by more than 4°C ▲T = T op - T max

21. OVERHEATING LONDON WEATHER FILE Between 09:00-15:30, May-Sept Number of hours greater than 24°C 26°C 28°C 30°C 32°C 123 45 17.5 5 1 30 YEAR

22. OVERHEATING BIRMINGHAM WEATHER FILE 30 YEAR Between 09:00-15:30, May-Sept Number of hours greater than 24°C 26°C 28°C 30°C 32°C 65.5 24.5 4.5 0.5

23. OVERHEATING LEEDS WEATHER FILE 30 YEAR Between 09:00-15:30, May-Sept Number of hours greater than 24°C 26°C 28°C 30°C 32°C 53.5 17.5 5

24. OVERHEATING CPW APPROACH : HYBRID

25. OVERHEATING CORE HYBRID APPROACH NVHR Thermal Mass Night purging Opening windows NVHR Thermal Mass LED Lighting Radiators

26. OVERHEATING CPW APPROACH : WINDOW DESIGN BB101 : >1.5% floor area : 5% in absence of modelling

27. OVERHEATING CPW APPROACH : LOCAL ASSISTED NATURAL VENT

28. OVERHEATING CPW APPROACH : LOCAL ASSISTED NATURAL VENT Natural Ventilation enhanced by a low power fan

29. OVERHEATING CPW APPROACH : LOCAL ASSISTED NATURAL VENT TEACHING SPACE

30. OVERHEATING CPW APPROACH : LOCAL ASSISTED NATURAL VENT Full fresh air mode (Summer):  Designed to reduce higher CO 2  and hotter temperature levels. The mixing damper is closed; allowing no re-circulation. Fresh air mixing mode:  For higher CO2 levels. Cooler outdoor air is mixed with recirculated air, where the ratio of fresh air is modulated to control temperature and CO2. Full re-circulation mode (Winter):   Fan running for colder conditions. The mixing damper is fully open allowing air to be extracted from the space and passed over an LPHW coil for heating. Full natural mode:  Unit shuts down, with windows open, allowing for natural ventilation. HOW IT WORKS

31. OVERHEATING CPW APPROACH : LOCAL ASSISTED NATURAL VENT PRO’S AND CON’S Easy to control Independent for each room Easy & fast to install Low SFP helps achieve Part L without renewables Meet noise BB93 Potential higher maintenance cost Unsightly Occupy window wall space

32. PART ‘L’

33. PART ‘L’ ROADMAP

34. PART ‘L’ FABRIC

35. PART ‘L’ FABRIC : WINDOWS Solar Energy (g-value ) Sunlight (light transmittance) Thermal Heat Loss (u-value) Element Targeted Value External Glazing ‘g’ Value 0.4 External Glazing Lt Value 0.71

36. PART ‘L’ FABRIC : AIR TIGHTNESS 2013 Part L Max 2013 Part L Carbon Model Low Energy Design 10m ³ /hr per m² 3m ³ /hr per m² 1m ³ /hr per m²

37. PART ‘L’ DYNAMIC MODELLING : NOTIONAL MODEL COMPARED AGAINST DEFAULTS