ZEMCH 2019 International Conference Proceedings April.2020 | Page 113
define the level of performance gap by setting different indoor temperatures between as‐designed
model and in‐used model, the monitored indoor temperatures were applied as indoor setting
temperature for in‐use simulation model and ASHRAE recommend temperature for as‐designed
simulation model.
Table 3. Summary of IEQ data from POE study
Temperature (°C)
Range
East enclosed office
East open office
West enclosed office
West open office
Corridor
19.9 ~ 23.1
21.2 ~ 23.3
21.2 ~ 23.8
20.2 ~ 23.2
20.9 ~ 23.7
Whole
Average
20.8
22.3
22.2
21.5
21.6
RH (%)
Occupied
Average
20.9
22.3
21.9
21.1
21.5
4.3. Energy performance gap in the case study building
Range
44.9 ~ 59.9
39.9 ~ 53.5
39.7 ~ 55.9
40.9 ~ 59.3
45.6 ~ 58.8
Whole
Average
52.6
47.5
49.1
51.1
52.7
Occupied
Average
53.5
48.4
50.9
53.3
53.8
To evaluate the energy efficiency of as‐designed model and energy consumption for each energy
simulation model, Trace 700 dynamic simulation software tool was used during the study. The overall
energy consumption with end‐use results for each simulation models were illustrated in Figure 3.
According to the simulation result, the baseline model, which used the ASHRAE 90.1 Appendix G
method, was the most energy consumed and the best case/benchmark was the as‐designed model. To
compare the energy consumption between the baseline model and the Abu Dhabi code, which showed
a difference by 7.4% less for the Abu Dhabi code where the reduction was mainly related with enhanced
building envelopes only. To improve accuracy of the energy simulation models, the in‐use model was
calibrated with energy audit analysis and POE data. After calibrating the model, in‐use building
consumed almost closed to the Abu Dhabi Code model where it consumed almost 25% more energy
consumption than the as‐designed model (Figure 3).
Figure 4. Dynamic energy simulation results
After finding performance gap in building operation in the case study building, it was simulated
with detailed dynamic simulation. The energy consumption was increased by 29.7% for lighting use
due to failing to operate correct lighting schedules in the corridors, by 39% for fan power due to
operating the VAV systems as CAV systems, and by 24.8% increased by cooling energy consumption
due to an incorrect operation of the HVAC systems with poor airtightness of the case study building.
Therefore, comparing the total energy consumption between as‐designed and in‐use model was almost
25% difference, which means the correct operation and careful management scheme could reduce the
energy consumption for the case study building by 25% and at the same time improves user comfort
experience of the building.
Using Energy Audit with POE Study to Reduce Energy Performance Gap in an Office Building in UAE
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