technology award case studies Electric EUI (kWh·ft2·yr) Natural Gas EUI (Therms·ft2·yr) Total Site EUI (kBtu·ft2·yr) ENERGY STAR Benchmark HDD Therms/HDD August 2005 to July 2006 37.8 1.41 270 36 3,490 77.4 August 2009 to July 2010 32.9 1.30 242 44 3,735 64.9 Campus Improvement 4.9 0.11 28 22% — 16% Building at a Glance Name: Advocate Lutheran General Hospital Location: Park Ridge, Ill. Owner: Advocate Healthcare Principal Use: Hospital Includes: Pediatric ICU, Oncology, ICU Occupants: 192 Patient Rooms Gross Square Footage: 380,000 Substantial Completion/Occupancy: 2009 Occupancy: 100% Table 1: Energy use data for the entire hospital before and after the new building addition. is 87.5% at full fire and 120°F (49°C) return water temperature and 92% at 100°F (38°C) return water temperature at full fire. The following strategies were used in conjunction with the condensing hot water boiler to maximize system efficiency. • Primary variable flow heating water system: This system maximizes energy savings in a more reliable and simplified manner compared to traditional primary/ secondary pumping systems by eliminating a set of pumps and possible mixing of supply and return water streams. • Hot water temperature reset: At an outside air temperature (OAT) of 0°F (–18°C) or less, the supply temperature is 180°F (82°C), while at OAT above 55°F (13°C) the supply temperature is 120°F (49°C). Cooling Systems. Energy-efficiency measures with the chilled water system include the following: www.info.hotims.com/37992-4 November 2011 ASHRAE Journal 53