ASHRAE Journal - December 2011 - 57

technology award case studies
Read July 7 June 7 May 6 2010 April 6 March 9 February 5 January 7 December 8 November 5 2009 October 6 September 4 August 6 Total Average Days 30 32 30 28 32 29 30 33 30 32 29 29 364 30.33 kWh 2,314,320 2,268,120 1,985,496 1,819,368 2,000,256 1,818,216 1,855,104 2,105,928 2,166,936 2,600,616 2,230,608 2,172,744 25,337,712 2,111,476 Maximum (kW) 4,608 4,416 4,320 4,032 3,936 4,032 3,936 3,936 4,512 4,416 4,800 4,608 4,800 4,296

Building at a Glance
Name: Kaiser Permanente Downey Medical Center Location: Downey, Calif. Owner: Kaiser Permanente Principal Use: Acute care hospital Includes: 352-bed patient tower with ICUs, isolation rooms, ORs, women services, nursery, emergency department, imaging, food service Gross Square Footage: 657,800 Conditioned Space: 651,000 Substantial Completion/Occupancy: October 2009 Occupancy: 100%

Table 1: One year of electrical energy use. design, but it also presented a challenge in designing the systems with minimal impact on other trades. To meet this challenge, the designer used an approach considered unique in early 2005. The submitted plans were prepared as an integrated engineering and detailing effort with 3-D detailed ductwork and pipes from the project’s inception. This allowed the completion of full detailing, support and seismic design, and ﬁnal trade coordination during the plan check review period, and an early start for construction. The ﬁnal result was the completion of project construction ﬁve months ahead of schedule. compromising the quality of health care and patient, physician, staff, and visitor safety (see sidebar “California Codes for Hospitals”). Special attention was paid to right sizing the air-handling systems. The 18 airhandling units, with a combined 542,300 cfm (255 937 L/s), provide 0.825 cfm/ft2 (0.389 L/s·m2) on average, which is well below the average airﬂow rate in many hospitals. Note that some high-heatproducing areas were supplemented by fan coil units on this project, which is not included in this number. Air-handling units and ducts were sized to allow a 10% airﬂow increase, if needed, mainly for future ﬂexibility. After two years of operations, the airﬂow has not needed to be increased to meet comfort needs. Avoiding circulating, cooling and reheating more than the necessary air volume in a 24-hour constant volume system is a critical part of an energyefﬁcient design. The air-handling units serving the hospital building are 100% outdoor supply air units with runaround heat recovery coils providing an efficient building HVAC system. To improve efﬁciency,
ASHRAE Journal 57

Energy Efficiency Solutions
To provide an energy-efﬁcient design for this project, while meeting all regulatory requirements and budget, several design features were used. The building is served by 18 airhandling units (AHUs), each major department is provided with a separate unit. This allows similar rooms with similar characteristics to be served by the same unit, eliminating unnecessary overcooling and reheating of spaces with diverse uses. All departments with humidiﬁcation and dehumidiﬁcation requirements are served separately from other zones for the same reason. During the commissioning process, the right temperature setpoints were established to achieve an energy-efﬁcient operation.

Energy Efficiency Considerations
Hospital design in California is code driven, resulting in energy use in California hospitals that is well above the national average. In the past few years, hospital owners and code authorities have been working toward reducing the energy demand of these buildings, while not
December 2011

ASHRAE Journal - December 2011

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