On the *.txs report, the electricity dollar values listed under the "Annual Installation Energy Use by Fuel Type" and "Annual Energy Use by Building Set and Fuel Type" pages include both energy and demand charges. To determine how much of that total cost is attributable to the energy vs. demand, the demand component (reported on the following page) may be subtracted from this total value.
Yes. FEDS now models and evaluates lighting controls, including occupancy sensors. To model existing lighting controls, the user must select the appropriate "yes" response to the "Existing lighting controls?" input and review the existing utilization factors. To infer reasonable utilization factors for the controlled lighting, specify the appropriate space type for the space where the lights exist.
FEDS will also automatically evaluate the savings potential and cost-effectiveness of lighting controls where they do not currently exist. In this scenario, select "no–evaluate occupancy sensor" and identify the most applicable space type. In this case, the "existing" utilization factors identify the portion of time that the lights are currently on, while the "with controls" utilization factors will be used by FEDS to model the impact of the occupancy sensor controls. The "number of sensors required" is used by the cost model to identify how many sensors need to be installed to control the current lighting.
No. FEDS infers parameters based on the most likely current condition of a building and its equipment. Inferences for an 1820 vintage building will reflect the typical improvements and upgrades that have occurred over time.
Each lamp and ballast modeled within FEDS has a rated life (specified in hours) associated with it. Actual replacement intervals are calculated within the model based on the light's modeled operating hours (based on utilization factors and occupancy schedules) and rated life of each component. When a lamp or ballast fails, FEDS accounts for the cost to replace the component by figuring both materials and labor requirements. These costs are tallied over the economic study period and reported as the non-annual maintenance cost. FEDS uses the non-annual maintenance cost along with energy and capital costs in determining which fixture can best provide the required level of service at the lowest life-cycle cost.
Emissions factors are used and relate a quantity of pollutant emitted (e.g., tons of CO2) per unit of fuel burned. There are factors for each of the six pollutant types corresponding to each main fuel type. To estimate emissions, FEDS multiplies the consumption value for each fuel type by the appropriate emission factor. The emissions factors for certain fuel types, (for example electricity) can vary significantly depending on factors, such as plant type (coal, gas, nuclear, hydropower) and source fuel composition (e.g., sulfur content) such that state average values are applied based on the typical generation resource mix supplying that state.
Exterior lighting, such as security or parking lot lights can be included in FEDS by selecting the exterior fixture location. This will set the heat to space to 0 and alter the calculation of utilization factors appropriate for typical nighttime operation.
Refer to Appendix G of the FEDS User's Guide. Ex: FL 2x4 4F40T12 STD2 = a 2-foot by 4-foot fluorescent fixture, with four 40 watt T12 (1.5 inch diameter) lamps, operated by two standard magnetic ballasts (designed to operate two lamps each).
If the building is newer than the rated life of the equipment in question, then the remaining life is equal to the difference of rated life and building age. If the building is older than the equipment's rated life, FEDS assumes that on average, equipment will be halfway through their life (but users can override this assumption and specify actual equipment vintage). Rated lives vary by equipment technology. Some examples of rated lives used in FEDS are:
envelope components (windows, insulation, etc.) – 40 years
lights – typically 25 years (Although the cost of replacing lamps and ballasts is figured into the analysis based on specific replacement intervals and hours of operation)
boilers – 40 years
furnaces – 20 years
chillers – 20 years
package AC units – 15 years
heat pumps – Air Source/15 years, Ground-Coupled/20 years
motors – 15 years
hot water heaters – electric, 12 years; gas, 10 years; distributed heat pump, 12 years; central heat pump, 15 years
FEDS contains a built-in database of building survey data and is able to infer a number of building parameters based on the small set of required inputs provided by the user. For example, FEDS uses information such as building type, location, floor area, and vintage to determine the most likely construction type and geometry. It uses similar information along with heating fuel type and cooling equipment, to determine the most likely heating technology and ventilation system parameters for a building. All inferences enable a user to model buildings without having intimate knowledge of the detailed engineering parameters. The resulting building prototype parameter values are statistically the most likely values based on the limited set of information provided. Of course, all inferred data may be easily overwritten by simply entering (locking) a value in the user interface screens.
FEDS draws upon a number of sources to determine inferable parameter values. Major sources include national building energy consumption surveys such as the Commercial Buildings Energy Consumption, Residential Energy Consumption Survey, large end-use studies such as the End-Use Load and Consumer Assessment Program, ASHRAE handbooks, building and equipment codes and standards, and manufacturers' data and extensive building audit and evaluation experience.
The utilization factors for lighting represent the portion of time particular lights are on, on average, over the building set. They are expressed as a fraction of the maximum possible load (i.e., 100% of the lights are on 100% of the time) for a given time period. FEDS infers the occupied and unoccupied period utilization factors based on what is typical on average for the lighting technology and use-area type. FEDS typically assumes that some lights are on even during unoccupied times for security, safety, or cleaning staff, or simply because lights were left on. During seasonally unoccupied months and other periods defined as non-operating, utilization factors are set to 0 for all lighting records except for exit lights, which are assumed to operate constantly.
Attractive NPVs, payback periods, and SIRs typically fall within certain ranges, which should always be positive. However, negative values are possible in a couple of instances and do not necessarily indicate an error. The first possibility is that the project is recommended for a technology or building component you identified as "replacement required". As such, FEDS will recommend the most cost-effective replacement option, but not require that it be cost effective. So, while it may be the best replacement option, it may exhibit seemingly nonsensical economic figures of merit. Similarly, if a building retrofit occurs due to central plant or thermal loop abandonment, it may also exhibit negative savings criteria. That simply means that the retrofit (e.g., replacing central steam service with an in-building boiler) was not cost effective when looking just at the building energy use and costs. But the value of abandoning the central plant and/or distribution loop (due to the accompanying reductions in thermal losses and O&M costs) provided a net positive gain when added to the negative savings at the building level. Thus, at the site level, taking the central plant and thermal loop savings into account, the net benefit is positive—but purely from the building perspective (reflected in the TXD and CSV reports) the change from steam to dedicated boiler was not cost effective. Reviewing the central plant and thermal loops section of the TXS report and looking for a positive abandonment value will provide additional detail on just how much of a net positive gain accrues do the abandoning the plant and/or loop.
A locked value, in terms of FEDS inputs, is one that the user has entered for an inferable parameter. This indicates to the model that this is a user-entered value and should not be updated (inferred). Clicking on the lock symbol can also lock a currently inferred value. When a value is locked, the lock icon will appear as a latched or closed lock. To unlock a value, simply click the icon again, changing it to an open or unlatched lock. This value will now be inferred the next time inferences are run.
The index code in following the existing technology description for a heating or cooling technology represents the technology record number. For example,{H2} indicates a heating technology is actually heating record #2 (as input in the user interface). This information can be valuable when dealing with heat/cool pairs with several heating and cooling records in a single building set.
Section 432 of the Energy Independence and Security Act of 2007 (EISA 432) requires U.S. federal agencies to perform energy and water evaluations of their covered facilities on a recurring basis and report their performance via the Compliance Tracking System (CTS). The FEDS CTS report is provided to help agencies compile and format results from their FEDS analyses to facilitate this reporting requirement. Measures identified with buildings modeled in FEDS are categorized and summarized into the CTS Evaluation Upload Template (in an Excel spreadsheet format).
The Energy Resilience and Conservation Investment Program (ERCIP) report (*.ecp, otherwise known as the DD 1391) is a special form required by certain U.S. Department of Defense agencies in order to submit projects for ERCIP funding. The ERCIP report is designed to facilitate the form preparation and submittal process.
The [Heating/Cooling] end use designation is used for existing heat pumps or heat/cool pairs. Because such technologies provide both heating and cooling, two rows are needed to describe them on the *.csv report. [HEATING/Cooling] indicates that the data on that row pertain to the heating technology (and overall economic impacts) while [Heating/COOLING] indicates that the data describes the cooling portion of the equipment (and no overall energy and economic data are shown).
The lighting use-area fixture density is the inferred fixtures per square foot and is based on typical lumen levels for different use-area types. It represents the average fixtures per square foot over the entire use-area (or building for single use-area buildings). Typically, the user will know the total number of fixtures in a use-area and can enter this and allow the software to calculate the fixtures per square foot.
For heat/cool pairs (separate heating and cooling technologies), information may be listed for both retrofits to new, more efficient equipment and to a heat pump. In some cases, it may be cost effective to replace the heating equipment (or cooling only, or both) with a newer unit of similar type, as well as replace both heat and cool simultaneously with a heat pump system. All cost-effective options will appear on the *.csv report. The best option can be determined by comparing the sum of the individual heat and cool annualized total life-cycle costing savings with that of the combined heat/cool system (i.e., heat pump).
The installed capital cost listed at the very bottom of the *.txd report represents the actual total cost including materials, labor, taxes, and overhead. It is the actual cost that would be paid to complete a project. The installed cost value listed under the life-cycle costs savings section displays both the present and annualized values of the installed cost as used in the life-cycle cost analysis. The present value of the installed cost may be less than the installed capital cost if the study period for the analysis is less than the life of the new equipment. This can occur when the remaining life of the existing technology is less than the life of the retrofit technology. In this case, the cost of the retrofit technology is annualized over its full rated life, but only the annualized costs occurring during the remaining life of the existing equipment is discounted back to the analysis year and used for a fair cost/benefit comparison.
No. At this time FEDS considers only fixture per fixture replacements that provide similar light output. However, the energy impact of correcting an over/under lit condition could be analyzed comparing by two consecutive FEDS baseline runs (by running without optimization).