AGENDA #5a

MEMORANDUM

TO:                  Mayor and Town Council

FROM:            W. Calvin Horton, Town Manager

SUBJECT:       Report on Fire Station #5 Energy Utilization

DATE:             January 12, 2004

BACKGROUND

Article VII, Section 5-110 of the Town of Chapel Hill Code of Ordinances requires that, at the end of a one year period after completion of a construction or major renovation project, the Town Manager submit a report to the Town Council on the energy utilization performance of the new or renovated building.   The purpose of this report is to meet the energy utilization reporting requirement for Fire Station #5.

DISCUSSION

Energy Efficient Design Features

Fire Station #5 was designed by Michael Hining Architects, Chapel Hill, North Carolina.  Experience with the design and construction of energy efficient buildings was one of the criteria used in the architect selection process.  Compliance with the provisions of Article VII, Section 5-110 of the Town of Chapel Hill Code of Ordinances was incorporated into the contract between the architect and the Town.  In their letter dated November 19, 2002, attached, Michael Hining Architects provided the Town Manager with a report on the energy saving features incorporated into the building.  Some of those features are summarized below:   

• Maintaining existing trees on the south side provided shade during the summer and helped reduce heat gain. 

• Kalwall insulating light panels were installed in the bay area and the living/dining room.  A review of the facility by NCSU’s Solar House determined the available daylight was judged as excellent with very little artificial light required during daylight hours to over 90% of the facility.

• The exterior walls were made of pre-cast autoclaved aerated concrete units, which are a highly insulating material.  The “R” value in the walls greatly exceeds the Building Code. 

• Light fixtures are high power, electronic ballast, and energy saving fixtures.

• Natural gas was used for the hot water heater and the furnaces.  This not only provided a more efficient heating fuel, but it was accomplished at a lower installation cost.

• All wood used was rapidly renewable southern pine if possible.  The construction debris was recycled when possible.

First Year Energy Consumption Performance

One way to test the success of our efforts to design and build an energy efficient facility is to track energy usage in terms of BTU’s consumed per square foot and compare it to our existing buildings.  We have collected energy consumption data for electricity and natural gas on Fire Station #5 for the period from November 2002 to October 2003 and compared it to six other Town buildings including the four other fire stations, Town Hall and the Library.  The results of this comparison appear on the attached graph. 

We note that understanding the usage of a building is crucial in evaluating the energy use data; it can explain differences between similarly constructed buildings and similarities of energy consumption of very different buildings.  Of the seven buildings in the comparison, Fire Station #5 is one of the most efficient in terms of electrical consumption; however, it is one of the least efficient in terms of natural gas consumption.  Based on a review of the natural gas bills, we believe that the comparatively high natural gas consumption is due to the requirement for heat in the large truck bays during the winter.  The natural gas bills are quite high from December through mid April.  The garage bays in Fire Station #5 were designed larger than the other fire stations, in terms of both square footage and ceiling height, to accommodate the trend toward larger fire trucks such as the Town’s ladder tower truck.

We believe that the comparatively good performance of Fire Station #2 is due in part to a limited renovation of that facility a few years ago when we replaced the heating and air conditioning systems, installed energy efficient lighting and installed more energy efficient replacement windows.  We believe that the apparently low natural gas consumption at Fire Station #4 is an anomaly due to the replacement of the natural gas heaters in the truck bays last winter.  The old failed heating system was off line for a significant part of the heating season.

Lessons Learned

The current Energy Ordinance requires a report one year after completion; however, we believe that a more accurate picture of the energy performance of a building would be achieved by collecting and reporting on this data in the second year after all systems are balanced.  The first year is a time to experiment with and adjust the balancing of the heating and air conditioning systems. A more meaningful evaluation should begin about four seasons after the heating system is first balanced.  The first year after commissioning is also a time when the staff is gaining familiarity with all the building system controls.

The current Energy Ordinance requires comparison of the energy efficiency of new building with what the 1997 NC Building Code would have required.  In talking with several energy engineering consulting firms, we found that no one had the computer programs to make such a comparison.  It would have been expensive to develop the necessary programs, and the information would have been of limited significance.  We are currently investigating alternatives to the comparison with the 1997 NC Building Code that would provide the Council with the information needed to measure our success in designing and constructing more energy efficient Town facilities.

Cost continues to be a major factor in achieving energy efficiency improvements in building construction.  Many of the more elaborate techniques such as solar energy, geothermal energy, automatic lighting controls and energy management systems have high up-front costs that are unaffordable within the limited construction dollars that have been available for most projects.  As in most municipal construction projects, the budget for Fire Station #5 was limited to the extent that the scope of the project was eventually decreased to achieve project completion within the budget.  In such a fiscally constrained environment, it will always be difficult to find resources to dedicate to those energy efficiency features that have a high up-front cost and a low rate of return on investment.    

Next steps include the review and revision of the current ordinance.  Our initial discussion of this topic with the Council’s Sustainability, Energy and Environment Committee was on February 26, 2003.  The Committee’s consensus was to ask the staff to develop a policy that states the same goals regarding energy usage and includes practicable means of evaluating success in reaching those goals, and to present the draft of that policy to the Committee.  We are seeking assistance from an energy consultant to complete the final stages of this work.

CONCLUSIONS

Fire Station #5 is among the most energy efficient of the Town’s buildings with respect to the consumption of electric power; however, during the winter months, it requires considerable consumption of natural gas.  We believe that the comparatively high consumption of natural gas during the winter months is a function of the size of the truck bays. 

ATTACHMENTS

1. Michael Hining Architect’s letter of November 19, 2002 (p. 4).

2. Graph of: Annual Energy Usage By Building – Nov 2002 to Oct 2003 (p. 6).