A Primer on Energy Modeling
Published by Igor Seryapin
Have you ever thought how much energy your building consumes or will consume in the future? Can you predict or estimate this consumption in a short period of time? The answer is yes. To do a quick and accurate estimate of a building energy use we can use Energy Modeling.
Energy Modeling is a great tool to estimate energy use in new and existing buildings. For this purpose, Cyclone uses a sophisticated software program that simulates building virtual environments and predicts energy patterns on an annual basis. Energy Modeling can estimate many realistic scenarios and assess all categories of energy consumption. It is an essential tool when designing high-performance buildings, especially net-zero energy buildings. Engaging an energy modeler early in the design process can help reduce building operation costs, enhance occupant comfort, and create a healthier and happier environment around us. And no doubt, all of us would like to leave a better environment to live in for future generations!
Energy Modeling is a helpful decision making tool for architects who can influence how the building will look and perform. It enables the architect to scientifically decide on building shape, site orientation, the amount of building glazing, and types of envelope materials specific to a particular climate – all of which will affect building construction and operation costs. Modeling multiple options of exterior wall, roof, and glazing thermal properties, along with moisture analysis allows for a well-informed selection of the envelope optimal design. In fact, designing an efficient building envelope is a critical component of building performance.
Lighting engineers could also benefit from Energy Modeling by being able to test and improve their designs. Here are a couple ways to use an energy model:
Energy Modeling can help determine the best lighting options and produce the most efficient design. Integrating daylighting strategies into a building and assessing its energy and visual comfort benefits can only be done using Energy Modeling as a daylight analysis has to account for the compound effect of the sun, surrounding environment, external shading devices, glazing properties, glare, and artificial lighting.
Energy Modeling enables mechanical engineers to test different HVAC systems, size equipment capacities, select optimal system efficiencies, and estimate system costs. For example, Energy Modeling can be used to investigate the performance of a conventional Chiller-Boiler system or a state-of the-art ground-source water VRF heat pump system.
Renewable energy potential for a project can also be assessed with Energy Modeling. Use it to find an optimal inclination angle and an area of PV panels, estimate wind turbine feasibility for a particular site, or minimize HVAC use by incorporating natural ventilation strategies. Get your energy results in a matter of hours!
When all design decisions are made and all specifications are put together, it’s time to get a building permit from a city. There are two ways to get a building permit to comply with energy code requirements:
The Prescriptive path means all building components must meet the code, including building envelope, internal and external lighting power densities, and HVAC equipment efficiencies. The Trade-Off path is applicable to envelope compliance only; it allows some components of the envelope to be below code minimum, as long as the overall envelope thermal performance is equal or better. If any of the other building components or the overall envelope thermal performance happen to be below the minimum requirements allowed by the energy code, your project must pursue the Performance path to obtain a permit. The Performance path allows you to tradeoff options between any components of the building. For example, you want to build a building with a 70% window to wall area ratio but the code allows only 40%. The Prescriptive path would not be an option in this case. Instead, you would use the Performance path using Energy Modeling to show that your building performs as well, or better, than the minimum allowed by the code. The negative effect of the increase in a glazing area would have to be offset by, let’s say, the project’s lighting or mechanical systems that perform better than what is required by the code. This way, your building might even out-perform the minimum code energy requirements in terms of annual energy consumption and cost.
Green building certifications, such as LEED or Living Building Challenge, are great marketing opportunities for any commercial or multi-family buildings. More and more people prefer to work and live in sustainable buildings, which offer not only comfort and energy savings but also have an environmentally-friendly vibe. To obtain any green certification, the design team is required to have an energy model to predict building energy performance and to show annual energy cost savings over the code minimum. Energy Modeling will help obtain credits in several LEED categories, including Energy and Atmosphere, Indoor Air Quality, and Water Use Reduction.
For existing buildings, we can use Energy Modeling to calculate savings from optimized building controls or retrofitted HVAC equipment. Models can estimate not only the cost savings due to reduced energy use, but provide a full life cycle cost analysis identifying the best solution for your building and the amount of money you want to spend at any given time period. Energy models of your existing buildings can even be calibrated to their actual energy consumption through collection of metered energy data. Energy calibration can help tune-up the building or find errors in operation due to human factors or system controls faults. There are many government programs that incentivize energy use reduction in existing buildings. Energy Modeling can be used to receive these incentives to spend on your building retrofits.
Here at Cyclone, we work on about 50 projects a year ranging from small car-washes to million square feet distribution centers, manufacturing and refrigeration facilities, high-rise multifamily buildings and student dormitories, offices and mixed-use buildings, schools and natatoriums. We can study your building, identify the most desirable and economically feasible options, and help you fund building improvements of your choice.
You name it, we can model it. It’s Your buildings, only better!