**5. Conclusions**

More than a third of global energy consumption and CO2 emission is generated by the building sector and the awareness of the importance of buildings' energy performance related to CO2 emissions has increased worldwide. Improving energy efficiency is one of the key policy directions for the UAE governmen<sup>t</sup> to tackle energy security, energy conservation, and climate change. As a direct response, to increase energy efficiency in the building sector in the UAE, substantial steps have been taken in recent decades such as setting up the minimum levels of U-values for building envelopes, introducing building rating systems, and improving HVAC systems' efficiency. However, there is still an extensive evidence which shows that the buildings usually do not perform as well as predicted whilst in-use and this discrepancy is commonly referred to as the "energy performance gap".

The focus area of this research is using the building energy audit data and the POE and to reduce the dynamic energy performance gap in one of the university buildings in the UAEU, UAE. To achieve the main objective of this study, the energy audit data and the POE, followed by a detailed dynamic simulation method, were applied to several simulation scenarios. Identifying the cause of discrepancies between the as-designed and actual building, and to increase the accuracy of the simulation model, POE and energy audit data were used for calibrating the simulation model (Scenario C) to validate (Scenario D).

The research clearly indicated that the case study building in-use condition was not operated as designed and almost a quarter of the cooling-related energy was wasted by mismanaged and poorly understood building's active system operations and management. This type of performance gap is commonly found in the UAE and can be easily solved without increasing the cost or extra investment for systems upgrade. This method is able to use the calibration of the actual conditions of the building with a computer-generated energy simulation model to improve the accuracy of the simulation model, and efforts to identify the underlying causes of the gap between numerical/computational predictions and actual usage as well. This research method is very cost effective, and less than one year of the return of investment could be achievable. It also shows that the energy audit and POE study are possible to reduce the dynamic energy performance gaps in the building sector by improving the indoor environment quality, especially after the buildings are occupied as in-use phase.

**Author Contributions:** Y.K.K. conceived the presented idea and developed the theory and performed the computations. Y.K.K. and L.B. verified the analytical methods. K.A.T.A. and H.A. encouraged Y.K.K. to investigate the POE study and supervised the findings of this work. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the UAEU, gran<sup>t</sup> name and numbers: 2018 Start-UP (31N380).

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The data presented in this study are available on request from the corresponding author. The data are not publicly available due to the case study building is governmental facility.

**Acknowledgments:** The authors would like to thank the UAEU for supporting the study and allowing for the measurements to take place.

**Conflicts of Interest:** The authors declare no conflict of interest and the funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.
