AutomatedBuildings.com Article - Shedding Some Light

Here we are in 2012, 133 years after Thomas Edison’s invention of the incandescent light bulb. Too bad Edison couldn’t get a glimpse of what the landscape looks like today with all of the variations of the basic device available to the public.

I think he would also be startled by the enormous nature and complexity of the overall infrastructure we casually refer to as the “Grid” and all of the tertiary data collection and control elements involved in managing overall use. Estimates vary as to what elements of usage are attributable to all forms of commercial lighting use in the U.S., in my opinion the DOE numbers are as valid as any available.
http://www.eia.gov/consumption/commercial/index.cfm

But whatever that percentage is in the commercial sector it is the most visible even though it is not the largest use component. It still amazes me in this day and age to drive through a metropolitan area at night anywhere in the country and observe many buildings lit up like Christmas trees. I am sure that the average person has the same reaction. What the average person doesn’t see, unlike the readers of Automated Buildings, is the probability that in concert with the 250 kW worth of inadequately controlled lighting operating at 9:00 PM, there is a strong likelihood that there are 650 kW of central plant components in operation and another 150 kW of air handling equipment moving and treating who knows how much outside air into the building envelope.

The focal point being use or utilization. The most basic tenets of energy conservation are when there is no one in the space, turn it off, turn it down, set it back. Easier said than done, particularly when it comes to lighting. The reasons are many. Between all of the different forms of office space infrastructure including private offices, collaborative workspace, meeting rooms, touchdown areas, open plan workstations, the number of control schemas needed are considerable.

Another hurdle is the existing electrical infrastructure being limited to circuiting in place in existing facilities.

Between these items the most logical choice the end user can make is to retrofit along lighting technology lines, T12 fluorescent to T8, T8 to LED etc. The ROI calculus is relatively straight forward. If the use basis is 12 hours per day the savings and return rate are fairly straight forward.

Now for the monkey wrench. Let us consider the 12 hours of on time. What is the actual utilization basis of each physical space in the building? 80%? 70%? 62%?

Actually, it is continuously dynamic and completely dependent upon the activity in the space. What may surprise the readers is that rarely is the physical use percentage during occupied cycles greater than 60%, and in fact closer to 40% in most commercial office space environments. Sounds implausible, doesn’t it? I will be completely candid here; my first reaction was skepticism as well.

Now take a look at this utilization activity report, Figure 1., which was generated by a commercially available service which has surveyed over 100,000 positions in multiple Fortune 100 firms worldwide among others, using a wireless technology supporting occupancy/utilization measurement.

The actual information is collected and tabulated in near real time giving accurate information on each seating position in the entire facility, down to the desk level as shown in the sample report format below, Figure 2. The actual survey of the entire facility was conducted over a four week period encompassing 635 positions on multiple floors.

Figure 2. - A table showing breakdown of results by workstation.

If you accept the physical findings then the question becomes how to provide intelligent control applications to further reduce the energy consumption of the lighting systems.

In the area represented above in Figure 3., the positions in red are unoccupied, those in green occupied. The most obvious target for lighting capacity control would be the task lighting at the individual workstations and depending upon higher level logic control and physical location, overhead lighting.

This becomes technically difficult and expensive when the lighting infrastructure is line voltage fluorescent fixtures. It becomes far more practical when the lighting infrastructure is LED and based upon PWM (Pulse Width Modulation) controlled low voltage drivers, with four to six luminaires per as shown below in Figure 4.

In Figure 5. below, a larger whole floor area where each position occupied is represented by a green icon. The initial reaction one would have is that this floor depicted below is highly utilized, and it is, except for 23% of the open plan workstations, whose occupants are most probably utilizing the meeting rooms on this floor. (Meeting Rooms bracketed in red.)

This particular facility is a major news organization office in London. This snapshot was taken at 9:12 AM on a Monday morning. In fact the wireless space utilization analysis system was installed at this facility not on the basis of controlling lighting, or augmenting control of HVAC systems but rather to gain an accurate understanding of exactly how the overall infrastructure meets or does not meet the physical requirements of the occupants and work flow. The overall costs of fitting out a modern commercial office space with furniture and related equipment in major metropolitan areas of the world is staggering. Getting it right translates into effective capital expenditure.

[an error occurred while processing this directive] What having this form of technical infrastructure in place now presents as an opportunity is the export of information to other building systems, which may include lighting, BAS, security and maintenance management systems.

What the space utilization sensors at each position may be populated with are temperature sensors so that in addition to providing the utilization data, a higher resolution temperature map of the space can be provided.

You may also check out an actual survey data compilation at the link below. Sort by department on Friday’s, and note “Sales” utilization rates after 12:00 PM.
http://89.105.105.220:8080/wisenet_demo/rdPage.aspx

What other facets of building operations can be improved upon or augmented using technology that is at the core application designed and integrated for a totally different set of purposes?

A side stream example is depicted in Figure 6 below. When the MEP design firm sat down and laid out the overall Electro/Mechanical design based around directed criteria they can usually account for the inevitable alterations to the space within the design. But due to the fact that there are so many items that can adversely affect environmental control performance this is not always the case.

Security systems are another area that the integrated system may be able to play a role in. Despite modern security systems ability to integrate highly sophisticated levels of technology, particularly where high resolution video surveillance products are in play, cameras and their supporting infrastructure are expensive. Now consider the possibility and advantage of being able to view a single screen and know precisely where individual seat positions are occupied in the entire facility.

The case basis still remains lighting control at the center. The more probable long term technology is LED integrated with wireless sensing and control elements. System portability over the effective life span of the infrastructure is a major factor to be considered. The cost difference between LED and fluorescent continues to shrink. Building designers, owners, managers and tenants are now more than ever looking at technologies that can have a measurable and continuous cost reduction impact.

Dave has spent 39 years of his career in various organizations with primary involvement being Instrumentation, Automation, Controls, HVAC and Energy Conservation.

Direct industry experience in Building Automation, HVAC Manufacturing, Performance Contracting, and for the past nine years principal involvement has been in developing and manufacturing 802.15.4 Wireless technology and products.

Dave is a Principal in KC Rep Source LLC, based in The Woodlands, Texas. KC Rep Source is an OEM and Distribution channel for Wireless products manufactured by Everex Communications. Current product development is focusing on integration of LED lighting products with Wireless RF Mesh control. Trend Lighting Corporation based in Taiwan is the development partner.

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