wireless lighting control: a life cycle cost evaluation of multiple lighting control strategies.
With the increasing demand for reducing lighting energy consumption, the ability to dynamically modify the energy usage profile in a space has great value for both building owners and operators, and the main utilities that the grid must respond.
This study evaluated the cost-effectiveness and potential energy savings of two typical office building lighting control renovation projects in different geographical locations in Boston and Los Angeles on 1980s or 19.
As detailed in the method section, vailable lighting control system is compared with research investment lighting control to take advantage of the return on reducing lighting energy costs. 1.
The main purpose of this study is to compare lighting control techniques that reduce energy use under code requirements and understand costs
The effectiveness of these technologies.
In addition, this study allows to assess the advantages of emerging, advanced and wireless lighting controls, including reducing the cost impact of cabling and tenant completion of office building controls during renovation.
The study also aims to provide a reference source for lighting designers and electrical engineers to communicate to customers the potential capabilities of the lighting control system, while conducting an analytical study of utility companies, to encourage public utility rebate programs that expand lighting control. 1.
2 Building selection the building selected for this study is based on an office building in 1970s with a typical 2\'x4 \'acoustic ceiling.
Select a 25,000 square foot floor of the building for analysis.
Assuming the height of the ceiling is 9 \'-
0 \"and standard internal reflection (
The windows are located on all sides of the building and the windows are 40% --to-
From 2\'-extended Wall ratio6\" to8\'-
0 above the finished floor, double
Glass and low
The ecological and visible transmission ratio of 65%.
As shown in the figure, the floor for this study
1. two different spatial planning strategies are used to evaluate their impact on energy use.
The western half of the floor features traditional space planning, and the surrounding private office is located near the windows and the internal open office.
An inverted space plan was used in the east half of the floor, maximizing daytime availability by setting up perimeter open offices near windows and internal private offices. 1.
The control strategy of this study examined six types of control systems.
For all control scenarios, it is assumed that the fixture itself remains the same except for the indicated ballast replacement.
Control scenario 0 \"energy baseline\" is established as an energy baseline and provides the minimum equipment required to meet the mandatory Control Regulations of ASHRAE 90. 1-2007.
Based on this energy baseline, potential savings from advanced control strategies are evaluated.
For the office space considered, mandatory requirements include automatic control and automatic shutdown of all enclosed spaces-
Open office space is 2,500 square feet.
Sensor or time-
The switch control can be used to meet these requirements, and the time is assumed-
Because it is usually the lowest, switch control is usedcost method. [
Figure 1 slightly]
Control scenario 1 \"localized control\" was established to check the cost impact of upgrading to a non-centralized control system.
This control strategy upgrade provides the minimum equipment required to meet the mandatory control regulations for California\'s title 24 2008, which can be considered a compilation of aggressive lighting control strategies.
Check-in requirements include-
Automatic control based on all closed areas.
Mandatory requirements also include photocell control for open office space around the daylight.
In order to meet the mandatory requirements for multi-level operation, it is assumed that the ballast is changed to provide the inside/outside switch.
Control scenario 2 \"relay panel switching\" adds an additional layer of flexibility and control through the central lighting redistribution panel.
This situation also enhances the occupants.
Control-based is achieved by adding vacancy sensors to all spaces.
Light cells are also included in the open office space that has access to daylight.
During the event, the vacancy sensor automatically turns off the lighting and requires manual-on operation.
Provide a photocell to detect the availability of daylight and signal the relevant panel to provide bi-
The level switching capability of the minimum internal working plane photoelectric level that remains consistent.
Replace the ballast in the area available during the day to allow switching on the inside/outside.
Control scene 3, \"dimming panel\", hard-
Wired function of relay panel control scene.
In this case, it is assumed that in addition to the office and support space that is not open during the day, existing ballasts in all areas are replaced by dimmable ballasts.
Added light battery to allow dimming during the day and high brightness
Reduce end dimming for energy use.
This scenario also includes the use of manually covered vacuum sensors in all locations.
In non-dark areas including non-daylighting open offices, lamps are powered by relay panels, which receive signals from occupancy sensors through the processor to trigger on/off actions.
Light fixtures for day lighting spaces, including open offices, meeting rooms, and private offices, receive input from occupancy rates and daylight sensors through dimming panels to automatically control the lighting level.
Control scenario 4 \"addressable ballast\" further expands hard-
Wired systems, providing digital addresses for all ballasts, and connecting them as systems through network cabling.
The digital address allows for separate ballast control, allowing for re-
Partitioning and flexibility in the life cycle of the system.
In addition to the support space, all spaces provide a photoelectric tube to allow daylight to darken and high brightness
End trim dimming.
The entire lighting system is controlled through a software application provided on the server that allows maintenance personnel to give feedback on lamp power outages and energy usage.
In this case, the addressable dimming ballast changes all the ballasts.
Control scenario 5 \"wireless partial dimming\" provides dimming in private offices, meeting rooms and open offices with access to daylight, while using wireless switch control throughout non-day lighting and supporting spaces.
The integration of Wirelessphotocell allows dimming of both to provide high
End the trim and torespond in the presence of daylight.
Batterypowered wirelessphotocell simply integrates into the scene by communicating directly with the area controller, which then signals to the dimming ballast adapter to dim the fixtureWired dual-
Technical occupancy sensors are also used in open office areas and wireless sensor adapters are used to connect sensors to wireless systems.
In the area with a lighting Channel, a dimming ballast is installed in the lamp.
Finally, the control scene 6 \"wireless full dimming\" provides the most powerful control system with full daytime dimming, high
End decoration dimming, Lumen maintenance dimming and occupancy perception for all major spaces.
This situation again uses wired and wireless connection sensors as well as wireless optical tubes, all of which communicate through wireless area controllers to provide control over the lamps and lanterns.
In this case, all ballasts change with dimming ballasts.
1 The design of the lighting and control system, while the building housing is considered a typical office building in 1970s, the research hypothesis, the lighting system has previously been upgraded from T12 fluorescent lamps with magnetic ballasts to T8 fluorescent lamps with electronic ballasts.
As a result, the existing fixture is considered 2\'x4 \'3-
As shown in the figure, t8 recessed parabolic troffer with standard instant start ballast. 2.
Assuming that the fixture is usually provided on the an8\' by 8\' grid of the entire space, there is only one fixture in the private office.
The flat lighting under this system is calculated as an average of 55 fc, which is typical for the lighting design of late1990.
For the control transformation, it is also assumed that the target lighting level has been reduced to 35 fc, reflecting the trend of the reduction of ambient illumination levels that are still within the scope of office recommendation.
Due to the assumed ballast upgrade, the lighting power density for each scenario varies depending on the actual ballast loss, as shown in Table 1. [
2 Capital cost 2. 2.
1 contractor equipment pricing Independent Contractors estimate the cost of capital and installation in each case, including components, cabling and installation costs. Using RSMeans 
Regional cost data, all capital costs are adjusted according to the appropriate regions of the country. 2. 2.
2 debugging costs the programming and debugging costs of each control strategy are estimated by an independent debugging agent.
This work includes the programming of various occupancy rates and daylight sensors, as well as the programming of all addressable and wireless components.
Debugging costs include verifying that the system is executed as expected.
Assume that the hourly rate of the debug agent is the same for both locations, but the hourly rate required for many debug tasks is adjusted using RSMeans (2009)
Regional cost data. 2.
Energy modeling 2. 3.
Perform daylight calculation daylight simulation 5 times a day for two locations (
Six o\'clock A. M. , nine o\'clock A. M. , twelve o\'clock P. M. , three o\'clock P. M. and six o\'clock P. M)
On clear and cloudy days.
Using the symmetry of the solar year, simulations were conducted to study the Daylight availability on two solstice, and 21 between each monthin.
In order to distribute the data in a complete calendar year, the monthly distribution of sunny and cloudy days at each location was determined based on the data of the National Association of oceans and atmosphere NOAA 2008]
And the monthly value is weighted accordingly.
The operating plane illumination of the electric lamp is calculated and used to determine the dim level of high brightness
In some control scenarios, the dimming and daylight dimming are ended.
When dimming is considered, the resulting energy is used
The end decoration and ballast performance were then determined.
Assume that shadows are drawn when indoor lighting exceeds 500fc. 2. 3.
2 in order to determine the impact of the occupants, the occupancy profile-
Based on control, estimates of hourly occupancy distribution were obtained from the National Renewable Energy Laboratory Deru 2007].
Hourly check-in on weekdays, Saturdays and Sundays is weighted to create a single situation.
Figure 4 shows these four types of occupancy. 3. [
Figure 3 slightly]2. 3.
3 The conversion behavior of the occupant is assumed to be in a space without daylight, or in a space that can be accessed on a cloudy day, and if controlled, the occupant will turn on 100% of the light.
On a clear day, you can enter the space during the day, assuming that the occupant will only turn on the lights of 70%. 2. 3.
4 occupancy sensor time delay in order to consider the energy saving of occupancy sensors, previous studies have found that the overall estimate of expected energy saving is provided based on the type of space and sensor delay time, as shown in Table 2.
For \"Auto scan\"
In addition to the control strategy, the energy saving estimate is the average energy saving of the carOff results. 2. 3.
Since this simulation is carried out hourly, the saving of energy consumption per hour, the impact of occupancy sensors on reducing energy use is of interest.
As shown in the figure, a series of curves are created showing the energy savings due to occupancy, which is a function of the occupancy percentage4. [
Figure 4 slightly]
When the occupancy rate of space is very low, it is thought that occupancy sensors can provide the greatest savings.
For private offices, meeting rooms, and support spaces, it is assumed that the relationship between energy conservation and occupancy is almost linear.
For open office, it is believed that energy saving will reach zero before the space is fully occupied.
For each curve throughout the occupancy range, the average savings are controlled to match the final savings identified in previous studies.
Expected savings per hour as a function of occupancy level and occupant type --
The control-based approach is then determined. 2. 3.
6 comprehensive energy saving per hour, the resulting energy use is determined as a percentage of the lighting power density installed during that time.
This calculation is based on the effect of daylight dimming, high
End trim and crewbased controls.
Finally, the annual total energy consumption of each area under each control scenario and the monthly peak power demand are determined. 2.
4 life cycle cost assessment life cycle cost analysis combining capital and commission costs with annual energy costs for each system.
Assuming the actual discount rate is 5%, the annual energy cost is 10-
Annual analysis period.
Adding capital costs to the present value of energy costs results in total lifecycle costs for each scenario. 2.
The scenario described is fictional and has never really built 5 key assumptions and limitations.
This makes a thorough analysis of the estimated cost of funding, energy, installation and commissioning.
However, the actual operating cost and equipment maintenance problems were not analyzed.
In addition, all functions of each control technology are applied to entities to provide maximum flexibility.
The existing fixture configuration is not adjusted from the current spacing of 8\'x8\', nor is the fixture
Disappointed in any situation.
This causes the level of illumination to be adjusted for all scenarios and areas that use photocells to darken or switch to the target illumination.
However, scenes and areas without photocells cannot provide the same tuned illumination.
Annual energy costs include the impact of NSTAR on the utility rate structure in Boston NSTAR 2010]
Southern California and Los Angeles [
Southern California Edison 2010.
Capital costs include rebates for dimming ballasts, sensors and control systems currently available from their respective utilities. 3 RESULTS 3.
1 annual energy use Figure 5 summarizes the expected annual energy density in Los Angeles and Boston in all six control scenarios, as well as the expected energy density in the energy baseline scenario.
As shown in the figure, due to the integration of occupancy rate, the wireless full dimming scenario is expected to have the lowest annual energy consumption.
Based on control, daylight acquisition and high
End trim dimming.
When considering these two positions, the results show that due to the similar distribution of lighting and occupancy control, the energy density per year is very similar due to the wireless full dimming and addressable ballast scenarios.
The energy density of the wireless partial dimming and dimming panel scene is similar to the light used
Responsive dimming of the surrounding space, but does not use the daylight sensor to provide a high level of tuning
End trim dimming.
Relay panels and local control scenarios provide similar energy use, with the energy density of the relay panels slightly lower due to the inclusion of the inside/outside switch function in all daylight-accessible fixture spaces.
Overall, however, all the advanced control strategies studied were able to provide significant antenna energy savings compared to the energy baseline.
Generally speaking, the lighting energy density in Los Angeles is lower than that in Boston, because the climate in Los Angeles shows more daytime than in Boston every month.
For control scenes containing automatic daylight-
Responsive dimming or switching, low energy density in Los Angeles is based on increased daytime availability.
For ASHRAE energy baseline that does not include daylight ,-
Responsive control, energy consumption difference based on hypothetical manual-
Behavior related to sky conditions on daytime spaceships. [
Figure 5 Slightly]3. 1.
1 Impact of spatial planning Figure 6 shows the annual energy density of each location, divided according to the type of spatial planning.
Obviously, for the day
In the response control scenario, the \"reverse space plan\" side of the model results in a significant reduction in the energy density at both locations.
For the energy baseline, the effect of daylight is not included
The change of energy density is mainly due to the distribution of internal space, as shown in the figure
7, and their related visits to the Book of Light and assumption-on behavior.
For control scenarios 4 and 6, including day-
End decoration dimming, the impact of space planning is minimal, because most dimming energy saving is due to high
End trim dimming. 3.
Results from Boston and Los Angeles show that advanced lighting control strategies can lead to lower longevity
Then the traditional control strategy.
Figure 8 shows the life cycle cost of various scenarios in Los Angeles.
Minimum life of wireless full dimming scene-
Considering the 10-year analysis cycle, the wireless partial dimming and addressable ballast scenarios follow closely, which means cycle costs.
Two traditional panels
The base-based system requires the highest initial investment and cannot save enough energy to offset the high cost.
Figure 9 shows the life cycle cost of various scenarios in Boston.
Wireless full dimming scene display has the shortest service life-
Consider the cycle cost of 10-time
During the annual analysis period, energy savings improved due to a slight increase in capital costs.
However, this scenario is followed by a wireless partial dimming scenario and an addressable ballast scenario, which provides high energy savings and reduces operating costs. [
Figure 6 slightly]
Again, traditional panels
Highest life based on scene-
The cycle cost is mainly due to the high cost of funds.
Upgrade to aTitle-
24 compatible scenes can be used as a benchmark for compiling efficient lighting controls at a lower cost than providing a complete panel
Based on the system, minimum commissioning investment is required and energy use is reduced to about 15% lower than ASHRAE energy baseline. [
Figure 9 omitted
4 Discussion 4.
1 cost of funds 4. 1.
1 Capital cost Category description analysis of capital costs provided by independent contractors based on specific categories.
Control equipment includes the cost of lighting control equipment provided to the project through dealers and contractors, including switches, control stations, occupancy and vacancy sensors, optical tubes, power packs and commissioning tools.
The equipment includes contractor installation switches, wall box dimmer, wall box occupancy sensors, labor costs, overhead, and electrical goods required for control stations and optical tubes.
Branch circuit wiring includes the cost of materials, labor and electrical goods required by contractors to provide power and control signals from panels to light loads.
It also includes the cost of routing control signal cabling between sensors and control components.
Demolition includes labor costs and overhead costs required by contractors to remove existing control equipment, including switches and branchescircuit wiring.
The lighting system includes the materials, labor and electrical commodity costs required by the contractor to install new ballasts and to make electrical connections from junction boxes to lamps.
The control system includes the cost of materials, labor, overhead and electrical goods required by the contractor to install relaypanel, dimming panel, contact interface, time switch, bus controller, server and processor.
The removal of the lighting system includes the cost, overhead and electrical goods required by the contractor to remove the existing ballast and its associated lines.
Debugging involves debugging the cost of agent debugging, programming, and calibration of the lighting control system.
Commissioning includes coordinating and developing the project requirements of the owner, reviewing the lighting control design and specifications, developing the commissioning specifications, reviewing the materials submitted by the contractor, and preparing the commissioning plan, verify that the installation meets the owner\'s project requirements and system performance verification.
Depending on the type of lighting control system, programming and calibration can vary.
The programming of an addressable ballast system requires more steps to locate a single ballast address and define the control group.
Sensor Calibration for all control systems is similar.
Programming and calibration include: identification, addressing, and establishment of communication between panels, ballasts, sensors and equipment (
Addressable ballast only);
Programming ballast control group (
Addressable ballast and wireless only);
Plan the dimming scenario, schedule, utility demand response strategy and daylight dimming response;
Calibration takes up sensor sensitivity and time delay;
And set up photos
Sensor set point, dead-
Band adjustment and fade rate. 4. 1.
2 breakdown of capital costs Figure 2 shows a breakdown of the total cost of capital for both locations.
Los Angeles and Figure 10
Six analytical control scenarios in Boston.
Due to the need for a lot of rewiring work, the traditional panel dimming scenario results in the highest cost of capital.
Although for wireless zoning and full dimming scenarios, the cost of the control device is the highest, the total cost of capital is lower than the traditional upgrade due to the reduced demand to restructure the current wiring or run additional conductors to carry the control signal.
This reinforces the need to have experienced contractors familiar with advanced control strategies and helps to realize the potential to significantly reduce installation costs.
Capital costs are not the same for both locations, as there is a regional difference in the appropriate hourly rate for certified electricians, both of which are involved in the installation and commissioning of the system. 4. 1.
3 Utility equipment rebates Total cost of capital for two locations also includes available equipment rebates for two power companies, as shown in the figure12.
In Los Angeles, rebates are provided based on the number of control devices such as occupancy sensors and optical tubes, resulting in a fairly uniform rebate in the control scenario.
In Boston, kickbacks are provided based on the number of controlled lighting devices, which generate larger rebates when controlling a larger amount of lighting. [
Figure 10 slightly][
Figure 11 omitted][
Energy costs 4. 2.
1 utility rate structure for Boston analysis, Rate Schedule B1 for NSTAR [NSTAR2010]
A tiered energy usage billing system and demand system were adopted and different rates were provided for summer peaks.
Travel arrangements to Los Angeles
2 Edison from Southern California [
Southern California Edison 2010was used.
It\'s a time. of-
Used schedle, separated from summer and winter, also consider-Peak, Mid-Peak and Off-Peak conditions.
Potential energy costs through daylight savings, the difference in utility rate structure is obvious
Dimming in response.
No time in Boston. of-
Schedule of use, cost-
The savings in reducing daytime peak energy use are less significant than in Los Angeles, where energy consumption peaked at the same time. 4. 2.
2 Energy and demand costs in each of the two locations and eight control scenarios, taking into account energy and demand costs, determine the annual energy cost density.
Overall, the cost of demand in Boston is higher than in Los Angeles.
In Los Angeles, a single demand charge rating is applied throughout the year, but in Boston, demand has increased significantly during the summer months.
Coupled with Boston\'s low sunshine capacity, demand peaks reached in the medium term
The result of the day is a significant increase in demand
Related annual costs.
Los Angeles\'s energy costs are much higher because of time. of-
In particular, scenes that do not use daylight-
Responsive controls result in much higher energy cost density in Los Angeles than in Boston, as peakpricing occurs near the peak of daylight supply. 4.
3 life cycle cost assessment can capture economic benefits well after initial cost reimbursement.
Figure 13 shows life
As a function of analyzing the cycle length, the cycle cost of six control scenarios in Los Angeles.
As shown in the figure, the lifetime of the wireless full dimming scene is the lowest
Cycle cost is 10-year period.
This is because, in addition to localized control scenarios, additional energy savings are saved by dimming in all spaces, plus not significant capital costs. [
The initial cost of the wireless partial dimming scene is lower than the local control scene, and less energy is used, thus shortening the life span
Cycle costs are generated immediately after installation is completed.
However, compared with partial dimming, the energy saving in the wireless full dimming scene is greater, the interruption
The balance between the two wireless scenarios in four to five years.
As shown in the figure, there is an interruption in the addressable ballast scene-
In the case that the analysis period is about four years, the balance point of the life cycle cost of having a localized control scenario indicates that compared with upgrading to a more standard system, the initial investment in the advanced control system was basically recovered within the first four years of ownership.
Both wired system upgrades and relay and dimming panel scenarios bring the highest life
Since the initial investment required to reconfigure the lighting control is very high, this is not offset with energy saving.
Figure 14 shows life
Cycle Cost of various control scenarios in Boston.
The capital cost of the wireless partial dimming and wireless full dimming scheme is lower than the localized control scheme, and the cost is maintained at a lower cost. of-
Ownership of the analysis.
Wireless All-dim bring extra energy saving effect, minimum 10-
Annual life cycle cost with disruption-
In about seven years, there is even a point between the two wireless scenarios.
The addressable ballast scenario requires a higher initial investment compared to the localized control scenario, but due to significant energy savings it has an interrupt
It takes about five years to use a localized control system.
The initial cost of the TheRelay panel and dimming panel scene is very high, resulting in a very high life span
Cyclecost, these systems do not reimburse the cost within the time frame of the analysis. [
Figure 14 omitted]
5 Conclusion the results of energy analysis show that advanced lighting control can save energy compared with traditional lighting control.
In this study, due to the stratification of occupancy, advanced lighting control is expected to save up to 49% of energy per year compared to the energy baseline
Sensing, daylight response and high
End trim dimming.
Wireless and wired network controls can be cost-effective, especially when utility rates are time-basedof-use.
For aggressive energy transformation strategies that adopt daylight and occupancy response control, the relay Paneland panel dimming lighting control is not cost-effective because the cost of rewiring the branch circuit is very high.
Intelligent Wireless and addressable lighting control systems can save more money and energy than traditional localized and centralized lighting control systems.
Other benefits of addressable lighting control not considered in cost analysis include ease of reconfigure, load-
Reports of shedding and maintenance.
The study also illustrates the impact of spatial planning on energy consumption.
As shown in the figure, traditional spatial planning results in higher energy density during the day
Since daylight penetration is limited to the surrounding private office, the responsive control system.
The inverted space plan allows the use of daylight throughout the open office, thus affecting a larger footprint and more occupants.
The increased commissioning costs are often used as a reason for choosing a traditional lighting control system for a network address lighting control system.
The results of this study show that the cost of rewiring in retrofit applications far exceeds the additional commissioning cost.
Utility rebates can provide incentives for projects that pursue energy efficiency but are limited by capital costs.
The result is in the figure.
10 and 11 show that even before the implementation of the utility rebate, wireless lighting control is very competitive with the lowest cost of capital.
When a utility rebate is associated with a controlled load such as dimming ballast excitation, the rebate can completely offset the additional cost of commissioning.
The research work was funded by Daintree, Inc. and was invested by 14 groups of work and energy products Association LLC. REFERENCES [DOE]U. S.
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