Normal/typical plug loads are accounted for (inferred) automatically within FEDS. These values can be viewed and/or changed from the miscellaneous equipment inputs in maximum detail display. The data is based on major end-use load surveys for typical plug load levels and accounts for the typical levels of equipment loads in a given use-area type. For example, for an office building this will account for typical levels of things, such as computers, printers, copiers, clocks, vending machines, coffee makers, and kitchenette equipment.
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.
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.
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).
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.
FEDS allows a negative value for percentage of heat to the conditioned space. For example, if the equipment has a COP of 2.0 and operates with an exterior condenser, then -200 should be entered for this value and the capacity should be half the actual rated capacity. (This will result in heating an amount equivalent to 200% of the unit's consumption as being rejected outside.)
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.
The typical FEDS user will not have detailed information available regarding plug load levels in order to adequately model them and will need to rely on the inferred values. However, miscellaneous equipment records may be modified or added if a load is unusual or atypical of the use-area type, or has an extremely large load (or one that sees extensive use) that is above and beyond what would be considered typical. Similarly, a user may want to reduce the capacity density for some areas deemed to have a lower load density than typical for that type of space, or even delete entire records when there is no equipment in use of a given type.
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).