The basic idea of Building Energy Modelling (BEM) or Building Simulation is the process of utilizing a computer to replicate a building and its parameters. It predicts various energy usages of the building’s future and hence has both energy and cost-saving benefits. The main outcomes of BEM include:

• Predict annual energy consumption and CO2 emissions.
• Display the breakdown of the various energy uses.
• Provide daylighting analysis and evaluate visual comfort.
• Provide solar shading analysis and airflow simulations for occupant comfort.
• Compare against various international guidelines for green building certifications.
• Determine life cycle analysis and payback.

The integration of BEM can occur during various stages of the building’s lifecycle. It is often integrated into the initial design phase to assess different design options early on. For example, BEM can help in determining the size and capacities of mechanical systems and optimize them before installing them in the building. BEM can also identify retrofit possibilities in existing buildings and allow energy consultants to increase energy savings and reduce operating costs. Smart building technologies can also be integrated with BEM to analyze real-time data from sensors and meters in existing buildings and to consistently monitor and improve the building’s performance during its lifetime. Most energy modeling is conducted to achieve green building certifications, However, its scope extends beyond certification and can be seen as an expression of our dedication to addressing climate change.

Who Benefits in the Process?

BEM serves as a valuable tool for several stakeholders, from the design process all the way through to the regulation and facilitation of the building. At the forefront of the process, designers and engineers will benefit in terms of the efficient computerized process compared to manual, lengthy calculations. It also helps them in assessing and optimizing the building’s energy performance early in the design process and make informed choices on glazings, construction materials, equipment, lighting, and HVAC systems, among other energy-consuming elements.

Building owners and facility managers can use BEM as a decision-making tool to find out the most cost-effective efficiency strategies to keep the building running while considering the environmental impact and occupant comfort (Efficiency Manitoba, 2020). They can determine that through life cycle payback analysis and by calculating the return of investment (ROI) for various energy-saving technologies used. They can further use BEM to achieve various green building certifications (e.g.: LEED, BREEAM, Energy Star) and market their buildings as sustainable. For example, energy modeling (Optimize Energy Performance credit) in the LEED v4.1 Building Design and Construction (BD+C) rating contributes to nearly one-fifth of the entire points and is also a prerequisite (USGBC, 2020).

Figure 1: LEED v4.1 Building Design and Construction (BD+C) Credit Breakdown

Building occupants stand to gain significantly from an energy-efficient structure, as it translates to a more pleasant and healthful living environment. This encompasses aspects like improved indoor air quality and comfortable thermal conditions. Moreover, if renewable energy systems like solar panels, heat pumps, and solar heating are integrated, occupants can experience reduced monthly expenses. Most importantly, this creates sustainable living and working conditions and leads to an environment with minimal energy waste and reduced greenhouse gas emissions.

How To Develop an Energy Model?

1. Building Geometry: The 3D model is replicated by following the architectural drawings and includes the glazings, doors, and shading elements, and must be accurately oriented.
2. Climate Data: Accurate location and weather data should be inserted due to the location-varying daylight hours, temperature differences, and ongoing global warming.
3. Construction Materials: Elements such as walls, roofs, and windows in the model shall have thermal properties equivalent to the actual building’s materials.
4. Occupancy and Loads: The building’s occupancy patterns, exterior and interior lighting loads, and equipment loads are one of the main consumptions of energy and can drastically affect energy savings.
5. HVAC Inputs: The heating, ventilation, and air conditioning (HVAC) system is the major energy consumer and is a major step in the design process for engineers and designers.
6. Simulation, Analysis, and Optimization: The computer simulation is conducted, and the overall energy consumption and the breakdown of each of the energy uses are analyzed. Elements in the energy model with high energy consumption or thermal comfort issues are adjusted accordingly, and the simulation is re-run.

Smart Building Technologies and Building Energy Modelling

The integration of smart building technologies and BEM creates a closed-loop system where real-time data from the smart technologies continuously updates the model and in turn, improves the building’s energy efficiency even during the operational stage. It allows for accurate analysis, optimization, and control of a building’s energy performance.

The initial step involves live data collection, for example, information on temperature, humidity, carbon dioxide levels, energy consumption, occupancy, etc. The data is analyzed to provide graphical representations of the trends over a period of time, which can range from daily to yearly. These analyzed data can be input into the previously created energy model, and the model can, in turn, be adjusted to create more optimized building operational behavior and energy consumption patterns. The main advantage of BEM is that it can be used to test different scenarios (e.g., verify which mechanical equipment is more energy efficient) and predict the energy consumption and cost savings before implementation on the real building. This continuously ongoing feedback between the smart building technologies and the building energy model drives energy-efficient enhancements throughout the building’s operational life.

CASE STUDY

A real-life representation of the integration was showcased at the Solar Decathlon Middle East (SDME) 2021 competition. The team from Heriot-Watt University designed and built a house consisting of renewable technologies, sustainable building materials, and smart building technologies. The enhanced smart interfaces and sensors in the house allowed the creation of a design simulation loop that enabled the team to visualize the real-time performance of the house.

Through an integration of IES (Integrated Environmental Solutions) and ICL tools, a dashboard was created that showcased key details about the house, including live temperature and carbon dioxide levels to both visitors and online users. Additionally, it also showcased graphical visualizations of the data for individual rooms in the house. As the competition period was only for a short duration, the data collected could not be used to enhance the efficiency of the house. Hence at the end of the competition, the live data was compared against the energy model created during the design stage to analyze the differences and create a better model and house in future competitions.

Our Energy Modeling team at Alpin Limited provides consultancy services on energy modeling techniques for construction projects and existing infrastructures. Reach out to us at contact@alpinme.com or give us a call at +971-2-234-6198.