ZEMCH 2019 International Conference Proceedings April.2020 | Page 110
Figure 1. illustrates the predicted and actual electricity consumption in three building sectors:
schools, general offices and university buildings. The graph depicts the median predicted and median
consumption for the buildings within the databases, which are assumed to be broadly representative
of each sectors. As shown, the measured electricity demands are approximately 60‐70% higher than
predicted in both schools and general offices, and over 85% higher than predicted in university
campuses [12].
2.2 Sources of the performance gap
There are many causes of the performance gap in between predicted and actual energy
performance in buildings. The causal factors related to both predictive and in‐use performance,
implying that current predictions tend to be unrealistically low whilst actual energy performance is
usually unnecessarily high. This in turn can be associated with the lack of feedback regarding actual
use and operation of buildings as well as the resulting energy consumption. Currently, there is a
significant lack of information concerning the actual energy performance of our existing building stock
[13]. A continued absence of such data is likely to lead to a progressive widening of the gap between
theory and practice, and a failure to achieve strategic goals [14].
A study of 60 commercial buildings findings are below and top 13 faults in commercial buildings
(Table 1) [15]:
Over 50% suffered from control problems.
40% had problems with HVAC equipment.
33% had sensors that were not operating properly.
15% of the building were actually missing specified equipment.
Table 1. Common faults in commercial buildings
Top 13 Faults in Commercial Buildings
Duck leakage
HAVC system operates continuously during
unoccupied period
Lighting system illuminating space during
unoccupied period
HAVC system improperly balanced
Improper refrigerant charge
Valve leakage
Economizer dampers operating incorrectly
Insufficient evaporator airflow
Improper controls setup/commissioning
Control component failure or degradation
Software programming errors
Improper controls hardware installation
Air‐cooled condenser fouling
3. Materials and Methods
Taking a case study approach, this research analyses the energy performance of a university
building in the United Arab Emirates University (UAEU), Al Ain, UAE. This research was guided by
ASHRAE Building Energy Audit Level 1 methodology, followed by POE monitoring study. Results
from the energy audit and POE monitoring data were used to calibrate and validate the dynamic energy
simulation model, aiming to produce more accurate predictions of energy consumption and find the
source of discrepancy of energy performance gap to reduce the performance gap and to improve user
comport with better indoor environmental quality.
3.1. Case study building description
The case study building is called ‘F1 Building’ (Figure 2) and home of three colleges (e.g. College
of Engineering, College of Science, and College of Food & Agriculture) through its three floors with
total area of building is around 21,360m². It was constructed as a low carbon building and was
completed in 2011. The building fully air‐conditioned, rooftop air handling unit (AHUs) provide
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ZEMCH 2019 International Conference l Seoul, Korea