CA CEG flashcards
CA CEG · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Energy Use Index
- Annual energy consumption divided by a normalization basis such as floor area or production output, letting facilities of the same function be compared after weather and activity adjustments.
- Load Factor
- Average load divided by peak load over a period; a low value indicates demand charges could be reduced by flattening peaks or shifting load.
- ASHRAE Level 2 Audit
- A detailed energy survey that includes an energy balance, end-use breakdown, and cost and savings estimates for identified measures, exceeding a walk-through assessment.
- Degree-Day Method
- Estimates annual heating or cooling energy as building UA times annual degree days times 24 hours, divided by system efficiency, for quick screening of envelope or plant changes.
- IPMVP Option C
- Whole-facility metering approach that uses utility bills and a regression baseline adjusted for weather and activity to determine total facility savings from a project.
- Routine Adjustment
- A change to the baseline made for independent variables such as weather, occupancy, or production that vary during the reporting period but are not caused by the project.
- Simple Payback
- Initial project cost divided by annual savings, expressed in years; it ignores the time value of money and all savings occurring after payback.
- Savings-to-Investment Ratio
- Present value of project savings divided by present value of project investment using the owner's discount rate; a ratio above one indicates a favorable project.
- Power Factor
- The ratio of real power in kilowatts to apparent power in kilovolt-amperes; low values increase current, losses, and utility penalty charges.
- Total Harmonic Distortion
- The root-sum-square of harmonic voltage or current magnitudes above the fundamental divided by the fundamental magnitude, expressed as a percentage.
- Demand Ratchet
- A billing mechanism that sets monthly demand charges from the highest peak recorded in a prior window, often eleven or twelve months, so one spike raises costs for a year.
- Sensible Heat Equation
- For air, sensible heat in Btu per hour equals 1.08 times cubic feet per minute times the dry-bulb temperature difference in degrees Fahrenheit.
- Chiller kW per Ton
- Chiller electrical input in kilowatts divided by cooling output in tons; it equals twelve divided by the coefficient of performance.
- Fan Affinity Law
- For a centrifugal fan, airflow varies with speed, pressure with speed squared, and shaft power with speed cubed, so modest speed reductions yield large energy savings.
- Boiler Combustion Efficiency
- One hundred percent minus stack losses, determined from flue gas temperature and oxygen or carbon dioxide content; excess air raises stack losses.
- Steam Trap Failure
- A trap stuck open passes live steam and wastes fuel, while a trap stuck closed traps condensate, causing water hammer and reduced heat transfer.
- Flash Steam
- Steam produced when high-pressure condensate is reduced to lower pressure; it can be recovered to a low-pressure header instead of vented.
- U-Factor
- Thermal transmittance of an assembly in Btu per hour per square foot per degree Fahrenheit; it is the reciprocal of the assembly R-value.
- Thermal Bridging
- Heat flow through highly conductive paths such as framing, shelf angles, or balconies that bypass insulation and lower the effective R-value of an assembly.
- Blower Door Test
- A pressurization test that measures building air leakage, reported as air changes per hour at fifty pascals, used to quantify infiltration and locate leaks.
- Luminous Efficacy
- Light output in lumens divided by electrical input in watts; it measures how efficiently a lamp converts power into visible light.
- Lighting Power Density
- Connected lighting wattage divided by floor area in watts per square foot; it is compared with code allowances by space type.
- VFD Cube Law
- For centrifugal pumps and fans, shaft power varies with the cube of speed, so reducing speed to eighty percent cuts power to about fifty-one percent.
- CHP Total Efficiency
- Useful electric output plus useful thermal output divided by fuel energy input; well-matched combined heat and power systems reach seventy to eighty percent.
- Heat Rate
- Fuel energy input in Btu divided by electric output in kilowatt-hours; lower values mean more efficient generation, with 3,412 Btu per kWh as the theoretical floor.
- Pinch Analysis
- A method that matches process heat sources and sinks by temperature level to identify minimum utility use and waste heat recovery opportunities.
- PV Capacity Factor
- Actual annual photovoltaic generation divided by the output the array would produce at full rated capacity for all 8,760 hours of the year.
- Betz Limit
- The maximum theoretical fraction, about fifty-nine percent, of the kinetic energy in a wind stream that a turbine rotor can extract.
- Levelized Cost of Energy
- Total present value of a generating project's capital, operating, and financing costs divided by its present value of energy output over the analysis period.
- Scope 2 Emissions
- Indirect greenhouse gas emissions from purchased electricity, steam, heat, or cooling; they can be reported using grid-average or contractual market-based methods.
- CO2 Equivalent
- A common emissions unit computed by multiplying each greenhouse gas mass by its global warming potential relative to carbon dioxide over a stated horizon.
- Renewable Energy Credit
- A tradable certificate representing the environmental attributes of one megawatt-hour of renewable generation, separate from the underlying electricity commodity.