Medical Construction & Design

SEP-OCT 2017

Medical Construction & Design (MCD) is the industry's leading source for news and information and reaches all disciplines involved in the healthcare construction and design process.

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MCDM AG.COM | SEPTEMBER /OCTOBER 2017 | Medical Construction & Design 31 internal plug loads within the space and 2) reduce peak heating and cooling loads down to a level where target loads can be achieved with radiant water-based systems. Some strategies to reduce the peak heating and cooling loads include high-performance envelope design and appropriate window confi guration and shading placement. Decoupling ventilation air from space conditioning After employing strategies to reduce the peak loads, design teams should explore alternative HVAC systems that separate the ventilation air supply from space conditioning needs. Alternative HVAC system options include active chilled beams and displacement ventilation used in conjunction with radiant heating/ cooling panels. The major benefi t to these systems is they reduce the amount of air required to be delivered to the space and can eliminate any associated reheat energ y. Both systems have better ventilation eff ectiveness and have been proven to improve indoor air quality and more eff ectively remove airborne contaminants. On the UVMMC Miller Building, triple-pane dynamic electrochromatic (self-tinting) glass was thoughtfully integrated into the façade to strategically introduce natural light and reduce peak heating and cooling loads. Active chilled beams were employed in one level of patient rooms and in the building core. Patient room equipment loads When engineers calculate cooling requirements, one of the key factors is the assumed equipment load in watts/ sf within any given space. Often, the maximum output or worst-case scenario is assumed. For this project Bard, Rao + Athanas performed a comprehensive study to determine the actual equipment loads for a typical patient room. The output (wattage) of each piece of equipment that could potentially be in the room was measured at three conditions: maximum/peak wattage, high-functioning use and typical standby operation mode. The results showed that the actual operating loads were half or less than what engineers would traditionally assume. This tailored approach to the engineering design contributed to a reduction in the overall cooling requirement assumptions for the building and provided signifi cant cost savings. Energy analysis of multiple HVAC systems and glazing options During the early phases of the UVMMC project, Thornton Tomasetti (sustainability consultant) performed a detailed energ y analysis of a single west-facing patient room. The intent of the study was to examine how energ y performance was impacted by six diff erent HVAC systems across three diff erent window confi gurations. The 18-scenario study examined variations of a traditional variable air volume system, active chilled beams and displacement ventilation along with glazing options that had 40 percent, 70 percent and 90 percent glass on the exposed exterior wall. The results illustrated a correlative relationship between glass area and HVAC system performance. While the displacement ventilation system performed well with the 40 percent glass ratio (EUI of 146 KBtu/sf/yr), the active chilled beam system performed better than all the other system combinations, ranging from an EUI of 135 to 146 depending on the amount of glass. Surprisingly, the active chilled beam confi gurations had the smallest delta in energ y performance between the 40 and 90 percent glazing option. In addition to the energ y savings study, each of the 18 combinations were priced by Whitting Turner, the From left: The greeter/reception desk is the fi rst point of arrival to the patient unit. It provides a point of general information and direction for visitors, taking the burden off of the adjacent caregivers' station staff. > Each patient at the new University of Vermont Medical Center Miller Building will have a medical/surgical telemetry bed and improved monitoring capability. Each enhanced technology room will cut down on patient transfers, assist with infection control and vastly improve the patient experience by increasing privacy and reducing noise. 458T Recent data shows large hospital buildings consume a total of 458 trillion Btu in major fuels. — 50 Average Energy Star score for hospitals using the U.S. Environmental Protection Agency's Energy Star Portfolio Manager —

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