MAIN MENUPREVIOUS MENU--------------------------------Search CD-ROMSearch ResultsPrint01.pdfWhole Campus Electricity Consumption PatternsResultsCONCLUSIONSAKNOWLEDGEMENTSHow Much Can a Campus Save on Utility Bills By Turning a 5-Workday Week Into a 4-Workday Week? Jijun Zhou Research Associate Energy System Laboratory Texas A&M University Tim Giebler Research Associate Energy Systems Laboratory Texas A&M University Guanghua Wei, P.E. Assistant Research Engineer Energy Systems Laboratory Texas A&M University Dan Turner, Ph.D., P.E. Professor Dept. of Mechanical Engineering Texas A&M University ABSTRACT The recent budget cuts campaign mandated by the governor’s office had all state agencies in Texas looking for ways to reduce revenue spending. One of the cost savings opportunities perceived by many university officials is to convert a typical 5-workday week into a 4-workday week (e.g., Monday to Thursday) with 10 working hours each day during the universities summer session. The potential savings come from the fact that the universities can be partially shut down during the prolonged weekends (Friday to Sunday). It is believed that the savings from partially shutting down an extra workday is much more significant than the marginal energy increase caused by the extended working hours during workdays. This paper analyzes the potential energy cost savings of this approach for three real cases. The savings can be largely estimated by comparing whole-campus electricity consumptions between typical weekdays and weekends (or holidays). Energy overheads caused by the extended working hours (two more hours per working day) were also estimated. A limited shutdown scenario (similar to a typical weekend schedule) and a more aggressive shutdown scenario (similar to a typical holiday schedule) during the weekend periods are presented. The potential savings opportunities were from 0.32% to 1.53% of the annual electricity bills for different universities. INTRODUCTION Several universities within the Texas A&M University Systems were investigating the possibility of utility energy savings by switching from a typical 5-workday week to a 4-workday week during the university’s summer session (June – August). The four working days are Monday through Thursday, 10 hours a day. By converting Friday from a typical weekday to a weekend day, the university will shut down most of the entire campus during the 3-day weekend, just like a long holiday (Christmas Break). Potential savings were estimated for three universities – Texas A&M University at Corpus Christi, Prairie View A&M University and Texas A&M International University, to help university officials make decision as whether it is worthwhile to take this approach in an effort to cut utility expenditures. CASE STUDY I – TEXAS A&M UNIVERSITY AT CORPUS CHRISTI Texas A&M University – Corpus Christi (TAMUCC) has a total conditioned area of approximately 1 million square feet, with a total annual electricity bill of nearly $1.5 million in the year of 2002. The summer months applicable for 4-workday weeks are June, July and August. The weighted average electricity price during this period is $0.0457/kWh from Monday to Friday, and $0.0359/kWh for Saturday and Sunday, based on the current electricity utility contract between the university and the utility company. ESL-IC-03-10-01 Proceedings of the Third International Conference for Enhanced Building Operations, Berkeley, California, October 13-15, 2003TAMUCC Whole Campus Electricity vs. Outside Air Temperature20,00030,00040,00050,00060,00070,00080,00090,000100,000110,00034 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90Outside Air Temperature (deg F)Whole Campus Electric (kWh/day)WeekdayWeekendHolidayPoly. (Weekday)Poly. (Weekend)Poly. (Holiday) Figure 1. TAMUCC Daily campus electricity consumption for weekdays, weekends and holidays Figure 1 shows the whole campus electricity (WCE) consumption (daily) profiles for weekdays, weekends and holidays. Daily WCE difference between a typical weekday and a typical weekend is around 20,000 kWh; Daily WCE difference between a typical weekend and a typical holiday is around 10,000 kWh; Daily WCE difference between a typical weekday and a typical holiday is around 30,000 kWh. Interestingly, the prolongation of 2 hours during the working days (Monday through Thursday) probably will not increase the campus’ HVAC load substantially. Most of the air-handing units had been operated from around 6:30 a.m. to 10:30 p.m. anyway though the working hours were from 8:00 a.m. to 5:00 p.m. Upon switching to the 4-working-day week schedule, operating schedules for most air-handling units schedules will remain unchanged for the 10-hour working days. Activity related electricity consumption (lighting, computers, printers, and other plug loads) during the four working days (Monday to Thursday) would be slightly higher than the current level due to the prolongation of the working hours. Assume that 25% of the campus lighting and other plug loads (mainly offices) would need to run 2 more hours per working day, or 8 hours a week, and that the average campus office lighting and plug loads is 2 Watts per square foot. For a total campus area of approximately 1,000,000 square feet, this amounts to an increase in electricity consumption of around 4,000 kWh per week due to the extra 2 hours from Monday to Thursday. Based on the above assumptions and analysis, the potential energy cost savings for a 4-workday week (instead of a 5-workday week) are calculated for the following two scenarios. Scenario 1 – Limited Shutdown Under this scenario, the campus will be partially shutdown on Fridays and Saturdays, just like the typical weekend operation. The campus will be shutdown more aggressively on Sundays, like the typical holiday operation. ESL-IC-03-10-01 Proceedings of the Third International Conference for Enhanced Building Operations, Berkeley, California, October 13-15, 2003Table 1. TAMUCC: Breakdown of 4-weekday week WCE savings for limited shutdown scenario Weekly Electricity Savings (kWh) Total WeeksSubtotal Savings (kWh)Electricity Price ($/kWh)Subtotal Savings ($) Mon - Thu (4,000) 12 (48,000) 0.0457 $ (2,193.60)Friday 20,000 12 240,000 0.0457 10,968.00$ Saturday - 12 - 0.03592 -$ Sunday 10,000 12 120,000 0.03592 4,310.40$ 312,000