Modeling a renovation/addition project varies somewhat on a case-by-case level. It really depends on how much of the project you would like to encompass into the analysis (ex. only renovation, or both existing+renovation), what kind of information you have on the existing projects (ex. BIM Models, Past Energy Reports, knowledge of existing construction), and if your design is only interior, single or multiple levels, or an entirely separate wing with the only connection being a transitional space. Answering these questions will help clarify how the project should proceed.
This article demonstrates how the stakeholders can use Cove.tool to optimize for cost and energy for renovation projects.
Section 1: Matching the Existing Geometry for Analysis
The first step to create an accurate energy model is to input proper values for the building geometry. Building geometry is composed of building height, orientation and areas of floor, roof, skylight, walls and glazing. Cove.tool’s modeling software plugins (Revit, Rhino, Grasshopper, and Sketchup) are created to streamline the import of building geometry. The custom data collector finds the project, collects the geometry and exports the correct values into the cloud database to run a fast and accurate energy analysis.
As far as setting up a model for geometry export, best practice is to only include area & building elements that directly depict the analysis space. For example, if you are renovating only the 1st level communal/lobby space in a multistory tower, and this program is only along the southern facade. In this scenario, the model would only have the floor area that bounds the lobby space, a south facade with wall and window objects and no roof objects, since the definition of a roof object requires direct radiation from above. Also to set up the energy benefits from a shaded space, you would place lobby ceiling in the shading device layer, and include interior walls that shade and bound the rest of the space.
If only certain part of the floor or building is being renovated then the geometry can also be set up as a mixed use for more detailed analysis. In this scenario, you would select one use type to represent the area being renovated, and another use type to represent the area not being renovated. The part of the building being renovated would have model values (u-value, r-value, HVAC etc) that exist, the part that is being renovated would automatically load up the energy code baseline values as selected by the prevalent energy code. You can utilize the chat box in the right bottom corner to reach out to the technical team if you need additional assistance in setting this up. When the model is set-up, ECM-style or the holistic cost vs optimization analysis can be performed as desired by the project team.
Section 2: Calibrate the Model Inputs to Match the Existing Conditions of the Building
The main purpose of renovation projects is to restore the building to a former better state. Therefore, in order to map the impact of the proposed improvements, the model needs to accurately reflect the existing condition of the building. And, manipulating the input parameters of the energy model such as air infiltration, U-values of roof and walls, glazing properties, lighting power density, plug loads, HVAC system properties, etc. to match up the energy usage indicated by utility bills will really help to do that.
Following images show different key-inputs cove.tool uses for the analysis:
Section 3: Modeling the Energy Conservation Measures using analysis.tool Cost vs Energy Optimization
The energy conservation strategies aim to reduce the consumption of energy by using energy more efficiently or by reducing the amount of service used. The Energy Conservation Measures (ECM) may include strategies like envelope material upgrades, switching to green energy, implementing shading strategies, etc. and bundles are created consisting of these strategies according to the targeted EUI for the renovated building. Cove.tool prepares the automated bundles which will help the user to hit the target EUI. Also, the bundles can be easily customized using ‘Change Options’ tab within the Cove.tool web app.
Furthermore, analysis.tool uses an advanced algorithm to optimize for the first cost and assist in making rigorous metric-based decisions on cost and energy.
In conclusion, renovation projects have a wide scope of upgrading decisions. With a fixed budget, it is possible to hit those rigorous energy targets with cove.tool's cost vs. energy optimization. The optimization algorithm sorts the bundles from higher performing lowest cost to lower performing higher cost so it is easier for the project team to make the key decisions in the early stages of the project.