RESEARCH 76 LD+A August 2015 www.ies.org T he retail sector, which represents 13 percent of California’s commercial lighting electricity use, has historically not embraced the use of light- ing controls. Reasons for this are many including perceived high cost, system complexity, and the potential for negative impacts on custom- ers and sales. California building lighting energy-efficiency standards for the retail sector have a higher lighting power density allowance and fewer requirements for mandatory controls in sales areas than other commercial and industrial building space types. The use of adaptive lighting systems, which automatically adjust their output and operation based on occupancy, daylight availability and other appli- cation-specific criteria, are underutilized in the retail sector, leaving a significant quantity of energy reduction potential unrealized. Retailers who design and apply an effective adaptive lighting control strategy could see a significant reduction in annual electricity costs and a rapid return on the investment. Researchers at CLTC are investigating strategies to optimize lighting designs and lighting control systems in order to maximize energy savings, minimize cost and reduce potential for negative impacts on business. Work is ongoing; how- ever, preliminary findings demonstrate several benefits of adaptive lighting and its ability to meet the needs of the retail sector in California. To achieve savings, retailers must elect to complete lighting system upgrades; however, most are hesitant to complete energy-efficiency projects. A retail market survey conducted in connection with this research identified several important factors that influence a retailer’s decision to complete an energy-efficient lighting upgrade (Figure 1). Almost half of retailers surveyed stated they would upgrade their lighting systems if it led to increased sales. Less than 20 percent of those sur- veyed said they would upgrade their system if it would only decrease their electricity cost and not increase sales. When asked “why” they held reserva- tions about conducting efficiency proj- ects, lack of understanding was cited as the number one reason. In addition, 53 percent responded that high first cost was a primary concern regarding lighting upgrades. USING WHAT YOU NEED, NOT WHAT’S ALLOWED To better understand the potential of updated lighting design and con- trols optimization in the retail sector, researchers began by comparing the illuminance levels resulting from appli- cation of maximum energy-code light- ing power allowances to those resulting from designs conforming to industry recommended illuminance levels. Il- luminance levels for both scenarios were estimated through building simu- lations. Reductions between that al- lowed by California’s building efficiency standards and that recommended in modern designs represent clear elec- tricity savings for retail businesses. Researchers examined two building types: a warehouse store and a depart- ment store (Tables 1 and 2). Three sets of lighting designs were completed for each building type. Each set utilized a different source type and included one design that utilized the maximum LPD allowed by 2013 Title 24’s area catego- ry method for retail merchandise sales Adaptive Lighting for Retail Environments By Samantha Havassy and Cori Jackson Figure 1: Reservations regarding lighting upgrades - retail business owners. Source: Consumer Preference Survey on Directional LED Replacement Lamps for Retail Application
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
RESEARCH
76 LD+A August 2015 www.ies.org
The retail sector, which represents 13 percent of California’s commercial
lighting electricity use, has historically not embraced the use of light-
ing controls. Reasons for this are many including perceived high cost,
system complexity, and the potential for negative impacts on custom-
ers and sales. California building lighting energy-eff iciency standards for the retail
sector have a higher lighting power density allowance and fewer requirements for
mandatory controls in sales areas than other commercial and industrial building
space types. The use of adaptive lighting systems, which automatically adjust their
output and operation based on occupancy, daylight availability and other appli-
cation-specific criteria, are underutilized in the retail sector, leaving a significant
quantity of energy reduction potential unrealized. Retailers who design and apply
an eff ective adaptive lighting control strategy could see a significant reduction in
annual electricity costs and a rapid return on the investment.
Researchers at CLTC are investigating strategies to optimize lighting designs
and lighting control systems in order to maximize energy savings, minimize cost
and reduce potential for negative impacts on business. Work is ongoing; how-
ever, preliminary findings demonstrate several benefits of adaptive lighting and
its ability to meet the needs of the retail sector in California.
To achieve savings, retailers must elect to complete lighting system upgrades;
however, most are hesitant to complete energy-eff iciency projects. A retail market
survey conducted in connection with this research identified several important
factors that influence a retailer’s decision to complete an energy-eff icient lighting
upgrade (Figure 1). Almost half of retailers surveyed stated they would upgrade
their lighting systems if it led to increased sales. Less than 20 percent of those sur-
veyed said they would upgrade their
system if it would only decrease their
electricity cost and not increase sales.
When asked “why” they held reserva-
tions about conducting eff iciency proj-
ects, lack of understanding was cited
as the number one reason. In addition,
53 percent responded that high first
cost was a primary concern regarding
lighting upgrades.
USING WHAT YOU NEED, NOT WHAT’S ALLOWED
To better understand the potential
of updated lighting design and con-
trols optimization in the retail sector,
researchers began by comparing the
illuminance levels resulting from appli-
cation of maximum energy-code light-
ing power allowances to those resulting
from designs conforming to industry
recommended illuminance levels. Il-
luminance levels for both scenarios
were estimated through building simu-
lations. Reductions between that al-
lowed by California’s building eff iciency
standards and that recommended in
modern designs represent clear elec-
tricity savings for retail businesses.
Researchers examined two building
types: a warehouse store and a depart-
ment store (Tables 1 and 2). Three sets
of lighting designs were completed for
each building type. Each set utilized a
diff erent source type and included one
design that utilized the maximum LPD
allowed by 2013 Title 24’s area catego-
ry method for retail merchandise sales
Adaptive Lighting for Retail EnvironmentsBy Samantha Havassy and Cori Jackson
Figure 1: Reservations regarding lighting upgrades - retail business owners.
OPTIMIZING CONTROLSMany factors contribute to the suc-
cess of control strategies. To maxi-
mize the value of an investment in
adaptive lighting, systems must be
optimized in terms of their operation.
Optimizing control settings such as
sensor time-out periods and the size
of sensor coverage zones is critical
to achieve maximum energy savings.
Researchers completed two studies
to understand how changes in light-
ing control settings aff ect overall
lighting energy use.
Occupancy Time-out and Zoning.
Most occupancy sensors allow us-
ers to select a time-out period, usu-
ally between 0 and 30 minutes, which
controls how quickly luminaires are
extinguished aft er the sensor no lon-
ger detects occupants in the space.
The length of the time-out period has
a direct influence on the energy use of
a lighting system. Systems controlled
Table 2: Department store - Electricity savings potential of an updated retail lighting design as compared to a design using the maximum LPD allowed by Title 24.
Source:CLTC
Table 1: Warehouse store - Electricity savings potential of a modern, retail light-ing design as compared to a design using the maximum LPD allowed by Title 24.
Defining ‘Adaptive’An adaptive lighting system automatically adjusts its light output and
operation to provide targeted light levels based on environmental condi-
tions, user schedules or other application-specific criteria. The system can
include many diff erent types of products including dimmable lamps and
luminaires, occupancy sensors, photocontrols, time clocks, communica-
tion panels and wireless communication nodes. An adaptive system can
also oft en be manually tuned, over time, in terms of light level, and in some
cases, color, to provide optimal lighting conditions as designated by sys-
tem operators, building owners or occupants.
plied to the space. During phase one,
tuning, scheduling and occupancy con-
trol were enabled. Data was collected
for two weeks under these control
conditions. In the second phase, task
specific tuning was added. The new lu-
minaires, excluding application of con-
trol measures, saved 52 percent annu-
ally as compared to a Title 24 compliant
lighting system (Table 5). The addition
of bi-level, occupancy-based control
per the schedule resulted in an addi-
tional 10 percent energy savings, or 62
percent total savings annually. Applica-
tion of a 20 percent high-end trim to
tune the system to deliver light levels
consistent with industry recommenda-
tions resulted in a final system savings
of approximately 70 percent.
Applications. Many commercially
available advanced lighting control
systems contain functions and fea-
tures that show potential to bring
significant energy reductions to retail
environments. The projects described
address models and demonstrations
that can be applied to department
stores, warehouse stores, midsized re-
tail and small businesses located with-
in multi-tenant light commercial prop-
erties. Sub-sectors within retail with
specific lighting needs have yet to be
addressed, including restaurant and
grocery applications. While control
strategies will diff er among retail sites,
at a minimum, strategies should utilize
scheduling, high-end trim and occu-
pancy-based dimming. Control zones
and control device settings follow-
ing the guidelines developed through
this project can be expected to show
Table 5: Annual energy savings - retail demonstration site.
1 Based on 3,640 annual hours of use (actual business operating hours).2 Weighted average of 1.7 W/sf in main retail space and 0.9 W/sf in bike repair area.
similar savings results. Demonstration
showed that these recommendations
can result in significant energy savings
as compared to 2013 Title 24 building
energy-eff iciency standards.
For more information on the require-
ments of Title 24, Part 6 2013, visit cltc.
ucdavis.edu/title24 and download the
Retail Lighting Guide.
1
2
Samantha Havassy was an assistant development engineer with CLTC from April 2012 to April 2015.