Comparison of EnergyPlus and IES to model a complex university building using three scenarios


Building energy modeling is a robust technique that can enable testing, analyzing, and optimizing different innovate building solutions and technologies. As a result, detailed whole building energy models are seen as useful tools for decision making and energy code compliance. However, these models work at a disaggregated level and thus need extensive databases composed of quantitative data on physically measurable variables (e.g. thermal characteristics of building envelope elements, internal temperatures, heating patterns, etc.). In this regard, one of the most discussed issues in the academic and industrial community is the energy performance gap, which often occurs due to the uncertainty and absence of reliable and accurate modeling input data.

Research has shown that different limitations apply to almost every building performance simulation (BPS) software available today. Therefore, in order to have confidence in the predictions of the whole-building energy models, it is necessary to have a thorough understanding of various features, specific capabilities, and disadvantages of BPS tools.

While existing studies have provided valuable information regarding the capabilities of different BPS tools to perform whole-building energy analysis, many of them have also demonstrated considerable discrepancies between the aggregated energy predictions, and especially for complex buildings, which can undermine the confidence in the use of BPS software for building design optimization and certification. Worse off, there is limited published information that compares different BPS tools on the HVAC system level and especially for complex institutional buildings.

In a recent publication, Dr. Miroslava Kavgic at University of Manitoba and her research team comprising Ali Al-janabi and Ali Mohammadzadeh in collaboration with Ms. Afaf Azzouz at Stantec’s Energy and Mechanical Engineering group proposed to extend the existing knowledge and understanding required for successful integration of BPS tools in different stages of the building design process and code compliance. In addition, they also attempted to address the energy performance gap due to the differences in simulation predictions that may be caused by algorithmic differences, modeling limitations, or input dissimilarities. To this quest, they adopted EnergyPlus (E+) and Integrated Environmental Solutions Virtual Environment (IES VE) software packages. Their work is currently published in the Journal of Building Engineering.

EnergyPlus (E+) and Integrated Environmental Solutions Virtual Environment (IES VE) are both whole-building simulation tool that can simulate multiple building systems while still providing design professionals with a suitable environment for detailed assessment and optimization of building and system designs. The researchers employed the aforementioned software packages in their study where two models were prepared. In general, three model scenarios were described and compared.

The authors reported that by carefully mapping the input parameters, very good agreement between the aggregated energy predictions of the two BPS tools was achieved. Additionally, with regard to temperature prediction of the EnergyPlus and IES models, it was established that the EnergyPlus model was more sensitive to the changes in the outdoor air temperatures compared to the IES model.

In summary, Canadian researchers presented pioneering works in the comparison of EnergyPlus and IES software packages. The approach used entailed comparison of EnergyPlus and IES models of a multi-purpose university building using three scenarios: free-floating, ideal air load system, and detailed. Overall, the approach allowed for an in-depth comparison of the different model complexities that are often used in the building design process. Altogether, valuable information that would come in handy in both academia and industrial set ups was presented.

Comparison of EnergyPlus and IES to model a complex university building using three scenarios: Free-floating, Ideal air load system, and Detailed - Advances in Engineering

About the author

Mr. Ali Al-janabi received his Master of Science in Civil Engineering at the University of Manitoba, Canada, in 2019 under the supervision of Dr. Miroslava Kavgic. Ali obtained his Bachelor of Civil Engineering (Honors) at the Infrastructure University Kuala Lumpur, Malaysia. Ali is an experienced Research Assistant with a demonstrated history of working in higher education and industry.

He is skilled in Energy modeling, EnegyPlus, data analysis, teamwork, and Leadership. During his study and research, Ali gained knowledge and experience in energy-efficient systems, building controls, HVAC, lighting and rating systems, energy conservation measures, greenhouse gas emission, and building energy simulation programs.

He has hands-on experience in analysis and reporting of energy and thermal performance of new and existing commercial, institutional, and residential buildings to improve the building’s performance. Ali has received multiple awards and scholarships throughout his Master’s, such as Stantec Graduate Fellowship in Engineering Scholarship 2019, International Graduate Student Entrance Scholarship (IGSES), Fellowship for Education Purposes – Natural Resources Institute (NRI) 2019, Fellowship For Educational Purposes – Faculty of Graduate Studies 2018, and Fellowship For Educational Purposes – Civil Engineering Department 2017.

About the author

Dr. Miroslava Kavgic’s is an assistant professor at civil engineering department at University of Manitoba in Winnipeg, Canada. She is a mechanical engineer of thermal science from Belgrade University in Belgrade, Serbia with M.Sc and Ph.D. in environmental design and engineering from University Colleague London, in London United Kingdom. Dr. Kavgic research interests are in the area of energy use in buildings which is dependent upon a complicated set of interactions between building components, systems, and equipment coupled with the complexities related to the need and behaviour of the building users.

Dr. Kavgic applies an interdisciplinary approach that comprises of advanced numerical analysis, comprehensive experimental tests, and field monitoring. She has worked primarily in the applied sciences, specializing in building envelopes and materials, indoor environmental quality, building energy systems, and advanced control strategies.

Dr. Miroslava Kavgic’s research objectives are to develop innovative, low-carbon, and cost-effective solutions and technologies that will accelerate the shift towards affordable and comfortable zero-carbon buildings in Canada. Dr. Kavgic published more than 30 peer-reviewed journal and conference papers.

Currently, she is working on various applications of latent heat storage technologies, bio-composite materials, passive and active solar systems to buildings exposed to extreme Canadian weather conditions. An important part of Dr. Kavgic’s work includes Indigenous Research focused on the improvements of housing performance in remote and rural areas.

About the author

In 2016 Mr. Ali Mohammadzadeh received his Bachelor degree in civil engineering from the University of Mazandaran, Iran. In 2017 Ali started his graduate study as an M.Sc student under the supervision of Dr. Miroslava Kavgic at the department of civil engineering of the University of Manitoba, Canada. Since entering the M.Sc program, his research projects involved building energy modeling, development of advanced building energy management, implementation of machine learning techniques to build effective optimization methodology and maximize building energy, and analysis of green building assessment methods focused on building energy efficiency, thermal comfort, and building control systems. Before joining the building engineering program,

Ali’s research extensively focused on fault detection in building structural elements using data-driven approaches. Ali is also an active member of Canadian green building council (LEED® Green AssociateTM) and Sustainable Building Manitoba.

About the author

Ms. Afaf Azzouz is a Buildings Performance Engineer within Stantec’s Energy and Mechanical Engineering group in Ottawa. She is a Building Energy Modeling Professional (BEMP) and has a Masters’ degree in Sustainable Buildings. Afaf has an in-depth understanding of energy modeling, passive design, Net-Zero buildings, and environmental life cycle assessments. Her interdisciplinary background enables her to verify and consult on the sustainability of building engineering systems (e.g. envelope, mechanical and electrical optimization strategies) of new construction and retrofit projects. She has also recently won the CaGBC Ontario Emerging Green Leader Award, acknowledging her contribution towards the sustainable buildings industry.

Her key recent projects include three Carbon Neutral Studies for commercial buildings in Ontario, which included calibrating the energy models of highly complex commercial buildings to match utility data, as well as suggest innovative design solutions to reach carbon neutrality. Other projects include Evolv1, the first building in Canada to be certified under the Zero Carbon Building Standard, and the UBC Brock Commons building, one of the tallest wood structures in Canada. She has also provided LEED and sustainability guidance on educational, commercial and healthcare projects. Further, she helped design the first 100% solar-powered, earth-constructed workers’ village in Egypt.

She is also an active member of the research community and presented her findings about the feasibility of NZE buildings in remote communities in the Building Simulation Conference and published her research about life-cycle energy optimization in Energy and Buildings Journal.


Ali Al-janabi, Miroslava Kavgic, Ali Mohammadzadeh, Afaf Azzouz. Comparison of EnergyPlus and IES to model a complex university building using three scenarios: Free-floating, Ideal air load system, and Detailed. Journal of Building Engineering, volume 22, Pages 262-280.

Go To Journal of Building Engineering

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