ENERGY AUDIT FOR BUILDDINGS. 05/04/2011 Tarik Al-Shemmeri 1

Transcription

1 ENERGY AUDIT FOR BUILDDINGS 05/04/2011 Tarik Al-Shemmeri 1

2 Energy Audits Is about the What, Where, and When energy is used And suggesting how this consumption can be reduced 05/04/2011 Tarik Al-Shemmeri 2

3 Energy Audits Energy Audit will provide:! financial,! operational and! Environmental benefits 05/04/2011 Tarik Al-Shemmeri 3

4 Energy Audits! Financial Benefits -! Reduced fuel and electricity bills.! Reduced operation and maintenance costs.! Reduced capital expenditure. 05/04/2011 Tarik Al-Shemmeri 4

5 Energy Audits! Operational Benefits -! Improved comfort levels! Improved efficiency! Better informed workers on global issues. 05/04/2011 Tarik Al-Shemmeri 5

6 Energy Audits! Environmental benefits! Reduced consumption of finite resources.! Reduced Pollution levels.! Improved public image. 05/04/2011 Tarik Al-Shemmeri 6

7 Assessing current building performance Two methods of Energy Audit:! The Regression Method, and! The NPI Method. 05/04/2011 Tarik Al-Shemmeri 7

8 Assessing current building performance! The Regression Method A standard method to assess the energy use in buildings, done by plotting the energy consumption each Month against the Degree days for that month. 05/04/2011 Tarik Al-Shemmeri 8

9 Assessing current building performance! The Regression Method This will show the trend in Energy consumption, is fitted by a linear relation, from this it is possible to predict future consumption. 05/04/2011 Tarik Al-Shemmeri 9

10 Month Regression Degree Day Figure Energy Consumed (GJ) January February March April May June July August September October November December /04/2011 Tarik Al-Shemmeri 10

11 Regression Method Energy Consumed (kwh) Degree Day 05/04/2011 Tarik Al-Shemmeri 11

12 NPI Method The Normalised Performance Indicator (NPI) comparing the building s energy consumption with similar type buildings. 05/04/2011 Tarik Al-Shemmeri 12

13 Calculating the NPI! Convert Energy Units to KWh! Find the Energy Used for Space Heating! Account for Weather! Account for Exposure! Add Non-Heating Energy Use! Account for Hours of Use Factor! Find Floor Area (Pool Area) (m 2 )! Calculate the Normalised Performance Indicator (NPI). 05/04/2011 Tarik Al-Shemmeri 13

14 Calculating the NPI! Step 1 Collate all energy use, Convert Energy Units to KWh 1 therm = kwh Natural Gas 1 litre = 10.6 kwh Oil 1 tonne = 7600 kwh Coal 05/04/2011 Tarik Al-Shemmeri 14

15 Calculating the NPI! Step 2 Find the Energy Used for Space Heating eg a sport centre with a swimming pool 65% of the energy is used in heating on average. 05/04/2011 Tarik Al-Shemmeri 15

16 Calculating the NPI! Step 3 Account for Weather Weather factor = 2462 / annual degree days 05/04/2011 Tarik Al-Shemmeri 16

17 Calculating the NPI! Step 4 Account for Exposure Factor = 1 for urban building = 1.1 for Sheltered buildings = 0.9 for Exposed buildings 05/04/2011 Tarik Al-Shemmeri 17

18 Calculating the NPI! Step 5 Add Non Space heating energy 05/04/2011 Tarik Al-Shemmeri 18

19 Calculating the NPI! Step 6 Multiply for hours of use Use factor = standard hours / actual hours in use 05/04/2011 Tarik Al-Shemmeri 19

20 Calculating the NPI! Step 7 Calculate Floor area in square meters 05/04/2011 Tarik Al-Shemmeri 20

21 Calculating the NPI! Step 8 Calculate NPI = corrected energy used / floor area 05/04/2011 Tarik Al-Shemmeri 21

22 Calculating the NPI! Step 9 Compare NPI with tabulated values for similar buildings and hence find out in which range of performance does your building lie? 05/04/2011 Tarik Al-Shemmeri 22

23 Comparisons of performance indicators! Good - generally have good controls and energy management procedures, but further energy savings are often still possible.! Fair - reasonable controls and energy management procedures, but significant energy savings should achievable.! Poor - unnecessarily high consumption and urgent action should be taken to remedy the situation. Substantial energy savings should result from the introduction of energy efficiency measures. 05/04/2011 Tarik Al-Shemmeri 23

24 Performance Yardsticks For Buildings Energy Efficiency Rating kwh/m 2 per year Type of Facility Good Fair Poor Pub < >470 Sports centre with swimming Pool. < >840 Theatre < >900 05/04/2011 Tarik Al-Shemmeri 24

25 Savings 1. By altering the physical construction of a building to reduce its heat loss eg double glazing, cavity insulation and loft insulation. 05/04/2011 Tarik Al-Shemmeri 25

26 Savings 2. Replacing/upgrading the equipment and controls to make it more efficient. Time switches, occupancy switches, and Thermostat controls. 05/04/2011 Tarik Al-Shemmeri 26

27 Savings 3. Shop around for the cheapest tariff. 05/04/2011 Tarik Al-Shemmeri 27

28 Savings 4. Continuous monitoring of Energy consumption. 05/04/2011 Tarik Al-Shemmeri 28

29 Savings 5. Using combined heat and power (CHP) plant to provide electricity and space heating/hot water. 05/04/2011 Tarik Al-Shemmeri 29

30 Case study 05/04/2011 Tarik Al-Shemmeri 30

31 Month Natural Gas (Therm) Electricity (kwh) January February March April May June July August September October November December TOTALS 11,155 63,045 05/04/2011 Tarik Al-Shemmeri 31

32 Gas Data Month Gas (Therm) Gas (GJ) Cost % Cost January February March April May June July August September October November December Totals 11, /04/2011 Tarik Al-Shemmeri 32

33 Electricity Data Month Elec. (kwh) Cost % Cost January February March April May June July August September October November December Totals 63, /04/2011 Tarik Al-Shemmeri 33

34 Energy Consumption 16% Natural Gas Electricity 84% 05/04/2011 Tarik Al-Shemmeri 34

35 Energy Cost 49% 51% Natural Gas Electricity 05/04/2011 Tarik Al-Shemmeri 35

36 Energy Consumption Gas (GJ) Electricity (G J) 50 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 05/04/2011 Tarik Al-Shemmeri 36

37 Energy Cost Gas ( ) Electricity ( ) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Tarik Al-Shemmeri 37 05/04/2011

38 Regression data Month Regression Degree Day Figure Energy Consumed (GJ) January February March April May June July August September October November December Totals /04/2011 Tarik Al-Shemmeri 38

39 The equation is given by : E = 0.365(DD) + 38 Regression Equation Graph Energy Consumed (GJ) Regression Degree Day Figure 05/04/2011 Tarik Al-Shemmeri 39

40 1. Convert your energy use into kwh units Add your quarterly or monthly use over one year for each fuel and enter below Natural gas Electricity Total energy use for the year { Therms x = x = kwh x 1 = = kwh kwh kwh A 2.Find your space heating energy use If you can identify any of the fuels above used only for space heating, enter the total energy use in kwh Add these to give total 0 kwh B If you cannot identify these then choose one of the following factors applied to the total energy used. For light industrial factory building Annual space heating energy Annual non-space heating energy Space heating factor = 0.80 A x 0.80 = x0.80 = B or C = A-D = = kwh kwh kwh C D E 3. Adjust the space heating energy to account for weather Find the Degree Days for the energy data year = 2523 The weather correction factor = 2462/2523 = Adjust the space heating energy to standard conditions = D x G =311998x0.976= Adjust the space heating energy to account for exposure kwh F G H Obtain the exposure factor from this chapter to suit the location of the building = 1 J Adjusted space heating energy = H x J = x 1 = kwh K 5. Find normalised annual energy use = E + K = = kwh L 6. Correct for hours of use of building Obtain standard hours of use = 2000 M Calculate the annual hours of use for your building -= 9x5x48 = 2160 N Hours of use factor M / N =2000/2160 = P Annual energy use for standard hours P x L = 0.926x = kwh Q 7. Find floor area = 25 x 25 = 625 m 2 m 2 R 8. Find the Normalised Performance Indicator (NPI) = Q / R = / 625 = Compare with yardstick - [ 180 to 240 kwh/m 2 ] Excessive Energy consumption kwh/m 2 POOR 05/04/2011 Tarik Al-Shemmeri 40

41 Calculation of Heat Losses width height D W W depth 05/04/2011 Tarik Al-Shemmeri 41

42 Element U-value W/m 2 K Area m 2 Temp. Difference ( o C) Heat loss W Door Windows Walls Roof Floor Fabric heat loss = TOTAL ( Doors, Windows, Walls, Roof & Floor) Ventilation Heat Loss = N V ΔT N= Heat gains from occupants 0 Heat gains from lights 0 Heat gains from machines 0 Net heat transfer for the building /04/2011 Tarik Al-Shemmeri 42

43 Energy Efficiency Measures 05/04/2011 Tarik Al-Shemmeri 43

44 Reduction of Fabric Losses Wall Insulation Area = 360 m2 cost of liner board = 8.20/m Cost = 360 * 8.2 = 2952 Roriginal = 1/Uoriginal = 1/2.3 = Rinsulation = x /k = 0.025/0.04 = Rnew = Roriginal + Rinsulation = = Unew = 1/ = AUwall original = 828 W/K AUwall new = * 360 = W/K ΔAUwall = ΔAU * 12.5 = kw Saving = * = /annum Pay back period = C/F = 2950/ = 7.4 years 05/04/2011 Tarik Al-Shemmeri 44

45 Roof Insulation Area = 900 m2 Cost of Rockwool = 6.40 / m2 Rnew = R old + R i = (1/2.6) + ( 0.1/0.04) = = Unew = 1 / = AUroof original = 900 x 2.6 = 2340 W/K AUroof new = 900 x = 312 W/K ΔAU = = 2028 W/K ΔQf = ΔAU * 12.5 = kw Saving = * = /annum Pay back period = C/F = 5760/ = 3.48 years 05/04/2011 Tarik Al-Shemmeri 45