AGENDA #5b
memorandum
to: Roger L. Stancil, Town Manager
from: Lance Norris, Public Works Director
subject: Report on Building Energy Improvements to the Police Station
date: March 3, 20087
PURPOSE
The purpose of this report is to respond to the Town Council’s request for an update on energy improvements to the Police Department as recommended by the Lego TM Mindstorms team 2255 of Chapel Hill.
BACKGROUND
On November 19, 2007 a group of seven young men, aged ten to thirteen years old presented to the Council their findings from an energy audit of the Police Station done on November 9, 2007 (attachment “A"). The audit was undertaken by the group as part of their entry into the Lego ™ “Mindstorms” competition; the theme of which was “Solving the Power Puzzle.” The Council directed the staff to review the audit and present findings to the Sustainability, Energy and Environment (SEE) Committee.
DISCUSSION
The audit involved examinations of lighting, the building envelope (walls, windows and roofing), mechanical (HVAC), major appliances, electronic devices, and alternative energy options. The group made recommendations on each part of the building examined. The staff response to each of these items is discussed below.
Lighting
The section of the audit dealing with lighting provided us with three primary recommendations; add occupancy sensors where practical, modernize ballasts in fluorescent fixtures and replace incandescent lighting with LED type.
Staff Comment: The maintenance staff concurs with the findings presented. Maintenance personnel have undertaken retrofits and upgrades to the lighting system concurrent with standard maintenance work: specifically, they have begun replacing incandescent lighting with LED and/or compact fluorescent lamps throughout the building, replacing standard light switches with occupancy sensors and inspecting and replacing ballasts as warranted. Concurrent with this effort, maintenance personnel are measuring light levels at specific work areas to ensure that the level of light is adequate.
Additionally, we have sought advice from lighting professionals to see if a more comprehensive lighting control system would be a reasonable investment for the Town.
Building Envelope
Windows-There were two options presented in the report; 1) Replace the existing windows (they occur only on the South face of the building) or 2) refill the interstitial space with inert gas.
Staff Comment: We have sought the advice of local glazing contractors to assist with the analysis of these recommendations and they will provide us with their recommendations based on the glazing assemblies in place and current best practices.
Walls- The group had several recommended options relative to types of insulation that could be added to the exterior walls of the building.
Staff Comment: While adding insulation in general is a good idea, the construction and orientation of the facility is such that we believe that the impact on energy use would be modest. The exterior walls are constructed of twelve inch think cast-in-place concrete and the building is set into the side of the hill. The North wall is largely sub-surface and the East and West walls covered by earth which slopes down to the ground floor along the length of the building axis.
Roofing- The options presented relative to the building’s roof were centered on installation of a “green roofing system.” Both intensive and extensive installations were discussed. Intensive green roofs tend to be characterized by thicker layers of soil, larger plants and shrubs and more “intensive” maintenance requirements; while, extensive green roofs are characterized by thinner layers of soils and smaller plants such as sedums.
Staff Comment:As the current roof assembly was installed in 2002 and is functioning well, replacement would not be a reasonable course of action at this time. When the roof has reached the point where it needs to be replaced, the possibility of a green roof assembly will be considered.
Mechanical Systems
The recommendations presented regarding the HVAC systems included: 1) Testing and balancing the system; 2) inspecting the duct work; 3) adhering to manufacturer’s recommend maintenance schedules and 4) evaluating the location and security of the thermostats. Additionally, the possibility of replacing the existing units with geothermal units at the end of their life was recommended.
Staff Comment: The system was installed in 2002 under the guidance of a professional engineering firm (Bass, Nixon & Kennedy) and was verified with 3rd party testing and balancing during the renovation. The systems are operational at this time and maintenance is provided by an independent Trane authorized contractor (Climate Control Experts). The maintenance of the units is fully compliant with the manufacturer’s recommendations.
Inspecting the duct work is an excellent recommendation and our maintenance staff will undertake that effort as part of the routine maintenance of the building. We believe there may be leaks that can be corrected and system efficiencies improved by this effort.
Additionally, the staff has met with energy management system providers to look at the feasibility of installing a comprehensive energy management system-similar to the system installed at the Town Operations Center. As possible configurations of such a system are determined, town staff will evaluate the options and provide recommendations as appropriate.
Major Appliances
As noted in the report, there are very few appliances at the Police Headquarters. We concur that when these items are replaced, the new units should be Energy Star rated.
The issue of upgrading to more energy efficient water fountains will be addressed as the units reach the end of their service life. The possibility of having water coolers is a reasonable point, as there are energy star models available, but brings with it other sustainability issues (transport impact etc.) that would need further examination.
Electronics
The primary recommendation of this section of the report concerned replacing CRT monitors with lower energy consuming LCD type monitors.
Staff Comment: As part of the normal operating procedures of the Town, computers are replaced on a recurring cycle. With each cycle of replacement, the number of devices that are energy star compliant increases. According to EPA standards, monitors that are Energy star compliant must meet the following requirments; in Off Mode the monitor must consume 1 watt or less; in Sleep Mode monitor must consume 2 watts or less and; and, in On Mode the maximum allowed power varies based on the computer monitor’s resolution.
Alternative Energy/Solar Power
The report noted that the facility was ideally oriented for solar power generation
Staff Comment: The standing seam roofing on the South side would present many options for the installation of solar panels for either photovoltaic applications or domestic hot water production. However, the report also notes that the majority of this building exposure is blocked by mature trees. While the installation of solar panels would be laudable, the trees have an aesthetic and environmental value that merits consideration. We do not recommend taking any action at this time that would be detrimental to these trees as we believe other facilities owned by the Town of Chapel Hill would be suitable candidate for such an installation.
Tracking Energy Utilization
We have established base line consumption information for electrical service at this facility. We will continue to track utilization to determine what effect our efforts have had on the overall energy efficiency of this facility.
SUMMARY
The Lego Mindstorms team made a number of useful recommendations for improving energy efficiency at the Police Department. We will implement those measures that we can and believe much of their report is consistent with our efforts to retrofit and upgrade existing buildings to directly reduce the carbon foot print of the Town. We will continue to provide updates to the SEE Committee and as requested to the full Council regarding these efforts.
ATTACHMENT
ADDITIONAL INFORMATION (March 3, 2008)