Active elements mechanical systems used in buildings to heat, cool, illuminate, and ventilate.
Algorithmic models predicated on an “if this then that” ruleset programmed into design software. The model can take time to set up, but it can simulate a large dataset quite efficiently.
Altitude angle comprises an angle off a horizontal plane to the sun’s position in the sky, ranging from 0 to a zenith of 90 degrees.
American Recovery and Reinvestment Act commonly called the “stimulus,” was designed to spur economic growth while creating new jobs and saving existing ones.
Annual energy costs the cost of operational building energy consumption from local tariffs and utility rate costs from energy fuel sources.
Annual energy use or consumption a combination of the annual heating and cooling loads, lighting, and equipment energy used for building operations.
Annual Sunlight Exposure (ASE) a measure of the space’s annual exposure to direct sun that in excess causes glare.
Aspect ratio the two-dimensional relationship between a building’s length and width.
Azimuth the measure of the sun’s location on a horizontal plane as an angle where north is 0, east is 90, south is 180, west is 270, and north is again 360degrees.
Baseline model a code-based BEM to investigate the standard reference design, which is a version of the proposed design that is minimally code-compliant and used to determine the maximum annual energy use requirement for compliance based on total building performance.
Bioclimatic a design that meets the human need for a comfortable interior environment tailored to the specific climate.
Brute Force Modeling (BFM) evaluates every possible combination of elements until it has exhausted all the possibilities.
Building Energy Modeling (BEM) a facet of BPS representing operational energy performance within a building.
Building Information Modeling (BIM) a digital representational process to generate and manage the physical and functional character of a building.
Building Performance Assessment (BPA) an early-stage model that focuses on various aspects of building design, giving value to and measuring the energy impacts of design decisions.
Building Performance Simulation (BPS) key abstractions representing functions of particular building elements.
Building science also known as Building physics, the study and analysis of building knowledge and experience to understand and control the physical phenomena affecting architecture.
Climate-adapted a building that incorporates passive environmental-control techniques to heat, cool, and ventilate to integrate the building within its climate.
Climate-rejecting a building that primarily relies on active systems—mechanical means—to heat, cool, and ventilate the building and where form and envelope serve solely as barriers between climate and conditioned space for environmental control purposes.
Climate zones geographical areas specific to ranges of temperature and humidity.
Continuous Daylight Autonomy (CDA) awards partial credit in a linear fashion to illumination values below the user-defined threshold.
Daylight autonomy (DA) a percentage of annual daytime hours a point in space is above the user-defined lux illumination level.
Daylight zoning relies on locating spaces that are suited for or require natural light in the appropriate location.
Design-dependent variables static building components related to conduction, solar, and ventilation, which change how the building relates to the exterior climate—primarily to the sun.
Design Performance Analysis (DPA) an early-stage model that focuses on various aspects of building design, giving value to and measuring the energy impacts of design decisions.
Dimming schedule a way to adjust a building’s lighting power consumption through a set lighting schedule.
Discrete elements individual aspects of a building, such as a wall or window.
Dynamic components elements of the constructed building that change over time.
Energy Conservation and Production Act (EPCA) signed into law in 1975 by Gerald Ford, this was the first time that commercial and public buildings became a target for energy conservation.
Energy conservation measures (ECMs) commonly an operational activity, building element or technology used to reduce a building’s energy consumption.
Energy Use Intensity (EUI) a reference number equal to the total annual energy use in kWh or MMBtus of energy consumed over the total building gross m2 or ft2 per year.
Equipment load the daily energy consumption of fixed items, such as the printers, copiers, and computers.
Fenestration the building’s windows, frames, glass, and any shading devices.
Fuel mix the source of energy production used locally by the utility provider to provide the building with electrical energy; typically coal, natural gas, nuclear, hydropower, photovoltaic, and wind.
Genetic algorithm a computer-programmed routine that randomly selects the best potential option and moves it forward.
Geometric indices metrics used to quantify a building’s geometry.
Global sensitivity analysis that describes how important a particular element is based on how many other elements it affects or that affect it.
Heating and cooling set points a set range of temperature variation allowed to maintain thermal comfort (the thermostat setting).
Home Energy Rating System (HERS) emerged from the RESNET organization formed from the insurance agencies responsible for evaluating energy efficiency in homes.
Hygrothermal refers to both moisture and heat.
Illumination the amount of visible light we see on a surface, measured in foot-candles or lux.
Infiltration also called air leakage; the incidental and unintentional movement of air through gaps or cracks in the building envelope.
Internal load-dominated a building’s energy consumption driven by the high density of occupants, lighting, and equipment requiring cooling year-round regardless of the climate.
Law of conservation of energy energy within the universe is always the same. Law of entropysecond law of thermodynamics; states that closed systems move to disorder over time.
Level of detail (development) (LOD) a term common in the use of BIM to describe the amount of information modeled during specific points of the design process.
Lifecycle cost the total cost of owning, operating, and maintaining a building over its economic life, including its fuel and energy costs.
Lighting power density (LPD) the predicted energy consumption in watts per square meter (W/m2) or square foot (W/ft2) of electric lights in a space.
Local sensitivity the statistical analysis of individual design elements or combinations of elements within an entire building system
Luminous efficacy (lm/W) a measure of how well a light source produces visible light.
Lux deficiency method calculates the extra illumination needed for the points that do not meet the SDA requirements, but the energy needed to compensate for the lack of illumination is different in each case.
MacLeamy’s curve the optimal project delivery relationship between cost and effort due to building information modeling.
Macroclimate the regional climate of a large area.
Massing a building geometry based on shape aggregation—piecing together similar or dissimilar shapes into a whole.
Microclimate the local set of weather conditions that differ from those of the surrounding area.
Non-design-dependent variables dynamic building components that are not design-specific, but material, construction, or technology dependent.
Occupancy schedule the percentage of the hourly schedule each day of the week, month, and year when people inhabit the building.
Occupant density the number of people in a space determined by the occupancy type and allowable density per code requirements.
Occupant load the number of people occupying the building.
One-at-a-time modeling investigation of one building element using BEM before moving onto the next item.
Parametric analysis an investigation of a set of ranges and their relationships.
Parametric odel a programmed software routine with a specific logic to reach a solution.
Passive solar design the use of architecture and climate to provide heating, cooling, and ventilation without mechanical (active) systems.
Performance-based design where the form of a building is an expression of its energy performance.
Perimeter and core thermal zoning of a building based on different thermal comfort needs for the spaces near the exterior walls versus those near the middle or core of the building.
Plug loads the transient energy consumption loads users may plug in at their workspaces, such as a cell phone charger, fan, or laptop.
Program analysis also architectural programming; this involves defining the building scope and the type of building that the client, owner, or developer is looking for.
Psychrometry study of the mixture of water vapor and air, specifically its application in heating, ventilation, and air-conditioning, and meteorology.
Relative humidity (RH) what the body senses is the temperature related to the amount of moisture in the air.
Sandbox model a BEM used to get a feel for the modeling environment, a study model—sometimes called a white-box model—to conduct preliminary analysis of the building.
Sequential search technique a linear analysis method of possible options testing each one until the desired result is achieved or the list is exhausted.
Shape effect the combination of a building’s orientation, aspect ratio, and stacking.
Shoebox model a typical representation of a small part of the building—perhaps just a typical room or a typical floorplate.
Simple-box method of starting the energy model using a a simple box about the size and shape of your building often using default data for HVAC systems and basic defaults for window–wall ratio, building geometry, and size.
Single zone a building with one thermal zone, either a room or an entire floorplate. Skin-dominated building also known as an external load-dominated building; the energy exchange (the heat loss or gain) primarily occurs through the building envelope—its skin.
Solar gain the sun’s contribution to the building’s heating and cooling requirement.
Solar heat gain coefficient (SHGC) the glazing’s efficacy at blocking the sun; expressed as a number from 0.1 to 1.0.
Space use the programmatic type of use in a building.
Spatial daylight autonomy (sDA) a measure of the annual usable daylight in a space.
Stacking a building’s vertical proportion and the number of floors, which increases as the building grows in height.
Static components parts of a BEM that, once built, will not change, such as the walls, roof, and window elements.
Surface reflectance a material’s efficacy at reflecting solar energy.
Thermal buffer spaces that help to mediate between internal and external thermal conditions.
Thermal comfort a subjective expression of a building occupant’s satisfaction with the interior environment.
Thermal conductance commonly known as its U-factor, refers to the amount of heat that passes through a material.
Thermal mass refers to a material’s ability to absorb solar radiation and store it for later use.
Thermal storage space A space used to store excess heat from higher thermal zones to use at different times of the day or night or in other areas of the building, essentially reusing the heat created by the building operation systems.
Thermal zone a BEM element containing spatial properties related to use, occupancy schedule, operation, energy consumption, and thermal comfort settings.
Thermal zoning considers the location of spaces based on heating and cooling needs to take advantage of synergies.
Utility cost what the local energy (electricity or gas) provider charges per unit of energy consumed.
Visible transmittance (VT) the fraction of visible light that passes through a window.
Weather files temperature, humidity, precipitation, and solar radiation data used to represent a historic picture of climate conditions for a specific location.
Whole building energy model (WBEM) the building performance simulation of all operational energy consumed within a building.
Zero energy performance index (zEPI) a scalar measurement of a building’s energy consumption related to its ability to achieve zero energy use.