Secondary Author(s)

Dutton, Wanda; Callahan, Michael; McIlvaine, Janet

Report Number

FSEC-CR-951-97

URL

http://publications.energyresearch.ucf.edu/wp-content/uploads/2018/06/FSEC-CR-951-97.pdf

Keywords

Energy Efficiency; Buildings; Florida

Abstract

A detailed survey of energy use and related physical and operational characteristics of Florida's public schools has been completed. A mailed survey instrument was sent to all 2,512 schools throughout the state in March 1996. A total of 1,298 surveys were returned -- a response rate of approximately 52%. Of these some 680 provided matching utility data. The survey data was analyzed to create a school energy use profile as well as to identify characteristics that may influence efficiency. Based on our findings, the total annual energy cost for the Florida school system totaled $205 million in 1995. As shown in Figure E-1, elementary schools make up almost half of this energy cost since they represent the largest total floor area within the Florida school system. Annual total energy costs averaged $1.24/ft2.

We ranked schools with complete data (654 facilities) by their energy use per square foot, or Energy Use Index (EUI, kBtu/ft2). The EUI's varied from 2 - 226 kBtu/ft2. The 10% of schools who used the most energy per square foot were identified as potential candidates for future improvement projects.

Finally, an analysis was performed of the statistical influences on energy use in schools based on the responses to the survey questionnaire against the matched utility data. The analysis showed some surprising influences:

  • Floor area and number of students and faculty were significant factors increasing annual energy use. High schools, Middle schools and vocational schools used more than elementary schools. Portable classrooms increased annual energy use by approximately 10,800 kWh each.
  • Schools conditioned on non-school days and those with central thermostats used more energy. Schools with manual lighting and clock thermostat controls used less. Cooling set points were shown to have a strong influence.
  • Classrooms with windows used 18% less energy than those without them. This may be due to reduced need for interior lighting, available ventilation or both.
  • Schools with light colored roofs used 7% less annual energy.
  • Schools relying predominantly on packaged cooling equipment rather than central chillers used 24% less energy. However, the reason for this finding stems from the fact that chillers in older schools showed evidence of very poor performance; newer chiller installations did not show this tendency. Elevated consumption associated with chillers may also reflect the need to consider zoning by evaluating space loads and schedules. Chiller sub-systems such as pumps, air handlers and cooling towers consume significant amounts of energy and efficient options should be selected.
  • Heat pump systems except water loop types were shown to be beneficial.
  • Schools with a history of humidity problems tended to use more energy. Complaints of indoor air quality (IAQ) and humidity problems were strongly related.
  • Schools using windows for ventilation reported significantly lower IAQ concerns although schools with higher cfm ventilation per student showed lower incidence of IAQ problems. We believe operable windows provide a sense of control to faculty and students on the IAQ issue. Greater cfm/student will tend to increase interior humidity levels which were shown to be strongly linked to IAQ concerns.
  • Facilities with ceiling fans in classrooms showed substantially reduced energy needs and higher cooling set point temperatures.
  • Schools with operable windows which could be opened for ventilation showed 13% lower energy use.
  • Low temperature air distribution systems showed no significant reduction to annual energy costs or monthly peak demand and were associated with increased complaints of indoor air quality and humidity problems. These systems were also associated with the largest increases to annual normalized energy use of all identified survey characteristics.

Date Published

7-1-1997

Notes

Reference Publication: Callahan, M., Parker, D., Dutton, W., McIlvaine, J., "Energy Efficiency for Florida Educational Facilities: The 1996 Energy Survey of Florida School," Submitted to Florida Department of Education, July, 1997.

Subjects

Buildings - Energy Efficiency; Florida

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