CIBSE GUIDANCE TM54
CIBSE guidance for specific end-uses
l Dynamic simulation models (DSMs) are used to estimate energy use for heating, cooling, fans and pumps, using more realistic profiles and inputs
l When possible, dialogue is undertaken between the designers and all prospective occupants about likely operating hours and energy management regimes
l All the energy uses in the building are included, rather than just the fixed building services
l Comparisons are made against existing energy use benchmarks to ensure that the results are within a range of likely outcomes
l Results are presented as a range with a high and low energy-use scenarios; providing a range of values acknowledges the uncertainty about predicting energy use
The TM54 approach proposes that spreadsheet calculations are used to establish some of the end-uses and the likely heat gains in the building and then takes the dynamic thermal model to calculate the energy use associated with heating, cooling and ventilation. It is assumed that a dynamic thermal model will have been built to demonstrate compliance with ADL2A, planning policy and so on and simply proposes uncoupling this model from the NCM templates. All of the calculations rely on structured discussions with prospective occupants to establish how the building is likely to be used, its intended occupancy hours, likely plant-run hours, operating and maintenance regimes and so forth. The methodology draws heavily on
the existing calculations in other CIBSE documents. For example, the lighting calculation is based on the lighting energy numeric indicator (LENI) and the lift and escalator calculations are based on the formulae for estimating energy use included in CIBSE Guide D. The methodology provides guidance
on calculating many of the energy uses in a building and then emphasises the importance of establishing all of the likely
300 250 200 150 100 50 0
Sensitivity analysis
Other Servers
Office
equipment Lighting
Fans, pumps, controls Cooling
Heating and hot
water (gas)
Figure 3: Sensitivity analysis for the case study building
450 400 350 300 250 200 150 100 50 0
Worst case
High end
Mid-range Low end
70 60 50 40 30 20 10
Electricity 0 Figure 4: Example of presenting a range of possible outcomes for the case study building Gas
Worst case
High end
Mid-range Low end
36
CIBSE Journal September 2013
www.cibsejournal.com
TM54 estimate 2020 weather data
Chillers SEER improved from 3·5 to 3·65 (approx. 4%)
7am – 7pm operation (1 less hour per day)
Weekend shutdown
Annual electricity consumption (kW·h/m2)
Annual consumption (kW·h/m2)
Annual gas consumption / (kW·h/m2)
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76