ENERGY AND COST SAVINGS THROUGH EMS OPTIMIZATION

摘要

An organization's energy management system (EMS) is not always effectively used to optimize energy use. This is often due to budget, labor, or time constraints. To demonstrate the energy and costs that could be saved through EMS optimization, two schools in Howard County, Maryland, were selected for a pilot study. The objective of the study was to demonstrate the savings from the EMS at a minimal cost to the County and to show the benefits of the EMS controlling as much of the equipment operation as possible. Clarksville Elementary School (CES) and River Hill High School (RHHS) were chosen after reviewing the energy use indices for all of the County schools. RHHS, a large modern high school, and CES, an older elementary school, provided a good contrast in terms of area and types of heating, ventilating and air conditioning (HVAC) equipment and controls. They represented a large fraction of the County schools. Field observations and electricity-use patterns at the two schools revealed several energy conservation measures (ECMs). Typical ECMs included remote on/off capability of the chiller at CES; locking arrangement for thermostats to prevent unauthorized setpoint changes in classrooms; rescheduling "unoccupied" time for various rooms to more closely follow school's actual weekly use; and tightening weekday, weekend and holiday schedules of HVAC units to more closely follow the actual use. These ECMs were implemented in the two schools at a cost of about $4,500. The measurement and verification (M&V) plan consisted of monitoring and comparing the energy and cost savings from the monthly bills with historical data for a period of six to eight months. In order to affect a proper comparison with historical utility meter data, adjustments to weather and number of days in the billing cycle were made. RHHS realized $1,700 of average monthly cost savings, while CES realized approximately $230. This case study clearly indicates the power and cost-saving potential of the EMS.