Creating efficient office lighting

An example of an office that used energy modeling for HVAC load analysis and a lighting optimization simulation analysis.


Figure 2: This office lobby shows the LED spot downlights used in combination with the T-5 HO fluorescent cove lighting and daylighting influence. Courtesy: ccrd partnersA remodel of a 17,000-net-sq-ft commercial office space in a circa-1929 office in downtown Houston took advantage of both energy modeling for HVAC load analysis and a lighting optimization simulation analysis to determine the impact on yearly energy consumption. The baseline model, which used the existing space design, was modeled with its existing lighting (2x4-ft recessed lay-in return air T-12 light fixtures) that had previously been retrofitted from to 2-lamp T-8 fixtures. The existing lighting demand was 10 kW (input power). This retrofit design was compared to the same space, using dimmable energy-efficient solid-state high-output T-5 high output and LED luminaires with occupancy sensing control and natural daylight from the existing north-facing palladia windows, resulting in a reduced peak power demand of 8.2 kW.

In comparing the two analyses for the floor cooling and heating load requirements, the existing design had required approximately 7 cooling ton-hrs per year consumption, while the remodeled floor require 6 cooling ton-hrs per year consumption. Peak heating demand increased from 92 kBtuh to 125 kBtuh as a result of the redesign, with energy consumption increased from 500 therms to 592 therms. Replacing the 2-lamp T-8 parabolic fixtures with programmable, occupancy based T-5 high-output lamp pendant luminaires and LED downlights offset with natural daylighting allowed for a yearly reduction in energy consumption of 16%. As a result of decreasing the lighting W/sq ft, the heating consumption increased by 15%.

The majority of load reduction was due to lighting controls and use of daylighting for the space. The existing lighting design was based on manual occupant switching. As occupants left for the day, lights would be switched off; when the cleaning staff switched lights on after-hours, lights would be left on overnight. To reduce lighting consumption, the renovation took advantage of vacancy sensing. With a vacancy sensor strategy, lights are turned off automatically soon after an area is vacated, but occupants must turn lights on when they re-enter the space. In the renovation, lights tied to a vacancy sensor turn off 2 hours after they are energized after-hours. After the cleaning crew has left the space, lighting would reduce to 30% of the design level in the space, rather than remain at 100% design level with switching.

This illustrates the benefit of application of lighting modeling and energy/load modeling in developing a lighting retrofit design that is unique to the building by incorporating daylighting and task lighting, employing new energy-efficient LED technology, and controlling supplemental lighting in order to achieve energy savings, enhanced lighting, reduced equipment cost, and improved comfort and aesthetic benefit for the tenant. 


David B. Duthu is board principal at ccrd, where he has more than 37 years of experience in the fields of mechanical engineering design, technical engineering design, and project management. Nolan Rome is associate principal and lead mechanical engineer for ccrd and has been responsible for the design of all types of healthcare facilities including hospital expansions, cancer centers, and imaging centers in multiple states.

No comments
The Top Plant program honors outstanding manufacturing facilities in North America. View the 2013 Top Plant.
The Product of the Year program recognizes products newly released in the manufacturing industries.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
A cool solution: Collaboration, chemistry leads to foundry coat product development; See the 2015 Product of the Year Finalists
Raising the standard: What's new with NFPA 70E; A global view of manufacturing; Maintenance data; Fit bearings properly
Sister act: Building on their father's legacy, a new generation moves Bales Metal Surface Solutions forward; Meet the 2015 Engineering Leaders Under 40
Cyber security cost-efficient for industrial control systems; Extracting full value from operational data; Managing cyber security risks
Drilling for Big Data: Managing the flow of information; Big data drilldown series: Challenge and opportunity; OT to IT: Creating a circle of improvement; Industry loses best workers, again
Pipeline vulnerabilities? Securing hydrocarbon transit; Predictive analytics hit the mainstream; Dirty pipelines decrease flow, production—pig your line; Ensuring pipeline physical and cyber security
Upgrading secondary control systems; Keeping enclosures conditioned; Diagnostics increase equipment uptime; Mechatronics simplifies machine design
Designing positive-energy buildings; Ensuring power quality; Complying with NFPA 110; Minimizing arc flash hazards
Building high availability into industrial computers; Of key metrics and myth busting; The truth about five common VFD myths

Annual Salary Survey

After almost a decade of uncertainty, the confidence of plant floor managers is soaring. Even with a number of challenges and while implementing new technologies, there is a renewed sense of optimism among plant managers about their business and their future.

The respondents to the 2014 Plant Engineering Salary Survey come from throughout the U.S. and serve a variety of industries, but they are uniform in their optimism about manufacturing. This year’s survey found 79% consider manufacturing a secure career. That’s up from 75% in 2013 and significantly higher than the 63% figure when Plant Engineering first started asking that question a decade ago.

Read more: 2014 Salary Survey: Confidence rises amid the challenges

Maintenance and reliability tips and best practices from the maintenance and reliability coaches at Allied Reliability Group.
The One Voice for Manufacturing blog reports on federal public policy issues impacting the manufacturing sector. One Voice is a joint effort by the National Tooling and Machining...
The Society for Maintenance and Reliability Professionals an organization devoted...
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
Maintenance is not optional in manufacturing. It’s a profit center, driving productivity and uptime while reducing overall repair costs.
The Lachance on CMMS blog is about current maintenance topics. Blogger Paul Lachance is president and chief technology officer for Smartware Group.