ASHRAE Journal - April 2010 - 43

technology award case studies
Building at a Glance
Name: Kaiser Template Hospitals Location: Four built in California so far (Sand Canyon [Irvine], Modesto, Antioch, and Vacaville) Owner: Kaiser Permanente Principal Use: Hospital Employees/Occupants: 175 to 225 beds Gross Square Footage: 340,000 ft2 Completion/Occupancy: Kaiser Permanente’s template hospitals are all designed according to California’s Title 24. 2005 – ongoing Occupancy: 100%

plant consists of two electric centrifugal chillers, one gas-fired chiller, and five draw-through cooling towers. Variablefrequency drives (VFDs) modulate tower fans, secondary chilled water pumps, and secondary heating hot water pumps. At Vacaville, life-cycle cost analyses led KP to implement a cogeneration scheme featuring two gas-fired microturbines, sized to reject enough heat to meet the new campus’s baseline 24/7 heating loads. The electricity generated is used on campus, offsetting less efficient energy generated by an inefficient remote plant and transmitted via the electrical grid. Air-handling systems were designed to supply 100% outdoor air to the hospital, and energy is recovered via coils in the exhaust air portion of the air-handling units (AHUs). Small horsepower pumps circulate water through these coils to coils upstream of the supply air section’s cooling coils, preheating or precooling the outdoor air. Any additional cooling is supplied by the units’ chilled water coils. This type of energy recovery is estimated to be 45% to 55% efficient. Although not as efficient as a dry bulb-based economizer on a recirculating unit, this means of energy recovery, coupled with a 100% outdoor air system, provides a high level of indoor air quality to the patients and staff.
April 2010

All of the Kaiser template hospitals were designed according to California’s Title 24 requirements, which tend to be more stringent than ASHRAE codes and regulations. To illustrate code compliance and exemplary hospital energy efficiency the Kaiser Permanente Medical Center in Antioch is used in this article, as the most information exists for this facility. The Antioch Template Hospital received the 2005 Savings by Design (SBD) Award, and according to the SBD computer analyses, the hospital was predicted to perform 23% better than an equivalent building meeting the Title 24 requirements. Based on this, the annual energy consumption would be approximately 22 GWh for the hospital alone. The associated avoided energy use would be approximately 3.1 GWh/yr, the avoided electrical demand approximately 442 kW, and the avoided gas consumption around 29,900 therms/yr (3 154 450 MJ/yr). The SBD analyses also determined that occupancy sensors, efficient light fixtures, and premium motors would yield economically reasonable payback periods compared to the Title 24 baseline building. A study period of 25 years was used using Department of Energy Federal Energy Management Program escalation rates.

National Distinctions/Awards: Pacific Gas and Electric’s 2005 Savings by Design Award

Data from the Antioch facility’s Pacific Gas & Energy (PG&E) utility bills for the last 12 months of operation are shown in Figure 1. According to this, the annual energy consumption is 35 GWh. This data was taken from a main meter that monitors the hospital building, CUP, and the medical office building (MOB). If PG&E data are prorated to include only the hospital program space (to match the SBD basis), the annual consumption is estimated as just under 20 GWh/yr. Although this comparison is only approximate due to the available energy consumption data, it can be seen that the Antioch template hospital exceeds Title 24 and ASHRAE requirements. It is expected that the cogeneration system implemented at the Vacaville facility will drive that campus’s energy consumption even lower.
Indoor Air Quality & Thermal Comfort

Local code ventilation and thermal comfort requirements are generally based on the American Institute of Architects
ASHRAE Journal 43

ASHRAE Journal - April 2010

Table of Contents for the Digital Edition of ASHRAE Journal - April 2010