2017 ASHRAE TECHNOLOGY AWARD CASE STUDIES 35 Years of Excellence University Lab Model for Energy Efficiency FIRST PLACE EDUCATIONAL FACILITIES,NEW The teaching and research lab brings together undergraduate labs and faculty research in the biology, chemistry, neuroscience, and bio- physics departments and provides a student commons area. It was the first major construction following an initiative to reduce car- bon emissions by 51% by 2025. BY BRADFORD CROWLEY, P.E. Energy Efficiency Energy consumption in a labora- tory is driven by outdoor air (OA) requirements, the heating and cool- JEFFREY TOTARO JEFFREY © ing to condition this air, and high BY BRADFORD CROWLEY, P.E., MEMBER ASHRAE internal heat gains from labora- tory equipment. The 105,000 gross eeting sustainability goals in a lab with 142 ft2 (9755 gross m2) Undergraduate Teaching Laboratories (UTL) build- fume hoods is a huge challenge for design ing uses a number of technologies, engineers. It’s an even taller order when strategies, and systems specifically those labs require the flexibility to change designed to mitigate the energy Mrapidly, such as from a wet lab to a dry one. Both were the impact of these drivers including: case for the new Undergraduate Teaching Laboratories at • Enthalpy and sensible energy recovery wheels to deliver neutral Johns Hopkins University (JHU). temperature ventilation air; Designers met those goals, creating a building that • Chilled beams, radiant floor used 50% less energy in 2016 compared to ASHRAE heating, and perimeter radiators; Standard 90.1-2007’s baseline. This helped the building • Waterside economizer using air- earn LEED Platinum certification. handling unit (AHU) cooling coils (free winter cooling); • District energy from campus Bradford Crowley, P.E., is an associate principal and team leader at Ballinger in Philadelphia. trigeneration plants; 26 ASHRAE JOURNAL ashrae.org JULY 2017 2017 ASHRAE TECHNOLOGY AWARD CASE STUDIES ABOVE Radiant floor and passive chilled beams in the commons. LEFT Exposed utilities, ceiling clouds, point HALKIN/MASON LLC PHOTOGRAPHY ARCHITECTURAL exhaust. © PHOTOS • High-efficiency lighting and reheat, neutral supply air allows compared with a glycol run- daylighting with occupancy sensor displacement makeup air delivery around recovery system. Together controls; system that significantly reduces with airflow-saving technolo- • High performance fume hoods; ductwork. Ducted air was sized only gies, the peak heating and cool- • Occupancy based airflow reset; as required to drive chilled beam ing was reduced by 4,000 MBH • “Decommissioning switches” to cooling. (1.2 MW) and 500 tons (1758 kW). turn off airflow to vacant labs; and Exhaust venturi valves maintain Figure 2 shows how reheat is elimi- • High performing envelope and the required exhaust flow (fume nated if air is supplied at a neu- minimal east/west glazing. hood flow and minimum air change tral temperature. In traditional Energy use is shown in Table 1. rate) in each laboratory. Exhausts systems, reheat is required when In 2016, energy consumption of on each floor are summed, and airflow requirements exceed the 144 kBtu per gross ft2 (1635 MJ large floor-based supply valves cooling requirement; this occurs per gross m2) was lower than the introduce the balance of the floor’s frequently in labs with high air modeled design, 192 kBtu per makeup air (minus ducted chilled gross ft2 (2180 MJ per gross m2), beam air) into a pressurized ple- BUILDING AT A GLANCE which confirmes a 50% cost sav- num above the corridor ceiling. ings over ASHRAE Standard 90.1- The makeup air is passively pulled Undergraduate 2007’s baseline of 408 kBtu per through large displacement grilles, Teaching gross ft2 (4633 MJ per gross m2). with fabric backdraft dampers that The installed air-handling system balance pressures between the Laboratories (Figure 1) uses two energy recovery plenum and labs. This air delivery wheels: a 3A molecular sieve-coated concept inherently creates a low- Location: Baltimore, Md. media enthalpy wheel and a sen- pressure, high-volumetric offset Owner: Johns Hopkins University sible wheel. The two wheels act to that ensures each laboratory is Principal Use: Teaching and research laboratories recover exhaust energy and reheat negatively pressurized with respect air toward a neutral temperature. to the corridor. It also significantly Includes: Teaching labs, research labs, vivarium, offices This design decouples ventilation simplifies controls, improves the requirements from heating/cooling quality of the building design via Employees/Occupants: 136 FTE/340 student demands. Active chilled beams pro- minimizing ductwork, and elimi- Occupancy: 90% vide sensible cooling throughout the nates dumping of cold (or reheated) building, while perimeter radiation air.1 Gross Square Footage: 105,000 offsets envelope heating losses. Dual energy recovery wheels Substantial Completion/Occupancy: July 2013 Because ventilation air is kept at have a large impact on system 68°F (20°C), reheat coils are not sizing. At the installed design air- National Distinctions/Awards: LEED Platinum required at supply terminals. In flow, the dual wheel system saves addition to reducing/eliminating 300 tons (1055 kW) of cooling JULY 2017 ashrae.org ASHRAE JOURNAL 27 ASHRAE TECHNOLOGY AWARD CASE STUDIES 2017 change rates (ventilation driven) or densities of TABLE 1 Monthly and annual building utility consumption. 2 fume hoods (hood driven). ENERGY CONSUMPTION Table 2 compares terminal loads and flows for two FISCAL YEAR 2016 ELECTRICITY (KWH) STEAM (MMBTU) CHILLED WATER (TON·HR) common lab modules, a biology lab and an organic July 224,207 124 124,583 chemistry teaching lab. The analysis demonstrates how reheat is nearly eliminated in the building. It August 224,433 173 105,333 also highlights the difference in ducted supply air that September 237,029 252 93,667 results from the combination of chilled beams, high October 233,478 403 31,333 performance fume hoods, and displacement systems. November 225,093 372 23,917 Overall, the total AHU capacity is 30% smaller than a December 201,002 367 21,167 baseline system, and approximately 40,000 cfm (18 January 198,870 563 4,833 878 L/s) of this air is delivered via the plenum. Fully- February 217,971 886 8,833 ducted supply air for the building is less than 0.6 cfm March 225,427 486 20,667 per gross ft2 (3 L/s per gross m2). April 226,507 439 31,583 To maximize performance, a manifolded exhaust sys- tem combines general and fume hood exhaust prior to May 215,665 341 47,000 the recovery system. While the use of wheels was criti- June 207,635 179 94,167 cal to this building’s impressive energy savings, risks TOTAL 2,637,315 4,585 607,083 of cross-contamination, vis-à-vis fume hood exhaust, had to be eval- High Momentum uated. Fortunately, the owner, with Exhaust Fans AHU With Dual Energy Recovery Wheels 25 years’ experience and 3 million cfm (1.4 million L/s) of installed Wheel Wheel wheel capacity in laboratory appli- cations, had expertise on this topic. Together with Johns Hopkins Supply Duct University safety officers (JHU Exhaust Duct Health Safety and Environment), Displacement Grille Supply the design team was able to evalu- Plenum ate and approve the use of wheels early in design. This process Active Chilled Beam included review of the building’s Hallway HVAC systems, the lab’s safety High Performing Perimeter Heat Fume Hood protocols, equipment specifica- tion and commissioning require- FIGURE 1 HVAC systems concept. ments, and an analysis of expected research and chemical use (including spill scenarios). Indoor Air Quality (IAQ) and Thermal Comfort The wheel manufacturer was sole-sourced based on While energy efficiency was an important driver in testing of desiccants cross-contamination approved design, laboratory safety and indoor environmental by the safety officer that limited the maximum car- quality were paramount. The design team met regularly ryover to 0.045% per wheel (0.09% for two wheels with officers from JHU Health Safety and Environment in series). Prior to occupancy, the system was com- to review design, set standards, and investigate new missioned and verified via a tracer SF6 gas test, in technologies. This process ensured that the laboratories accordance with ASHRAE Standard 84-2008, Method of exceeded all safety requirements and provided new Testing Air-to-Air Heat/Energy Exchangers. See “Code and direction for future lab designs at the campus. Safety Concerns Using Desiccant Wheels” for more on High performance fume hoods were used to reduce wheel safety. airflow. Hood velocities were designed to maintain 28 ASHRAE JOURNAL ashrae.org JULY 2017 2017 ASHRAE TECHNOLOGY AWARD CASE STUDIES 65 fpm (0.33 m/s) at 18 in. (457 mm) sash height versus the standard 100 fpm (0.51 Process 1 to 2: Enthalpy Wheel Process 2 to 3: Coiling Coil m/s). The hood was witness-tested at the Process 3 to 4: Sensible Wheel factory, by owner and engineer, to pass Process 4 to 5: Room Loads ASHRAE Standard 110-1995, Method of Testing 140 Performance of Laboratory Fume Hoods (8L as Cooling Load: manufactured 0.05 factory test pass crite- 2.7 tons/1,000 cfm 1 Outdoor Air: 120 95°F DB, 78°F WB ria) with a full open sash (27 in. [686 mm] 100 at 45 fpm [0.23 m/s]), as well as at the 18 2 80 in. (457 mm) operating height. This test 5 Room Condition: 74°F DB, 50% RH 60 was essential before acceptance because it 3 4 Humidity Ratio (Grains) proved containment under conditions in 40 which occupants (undergraduate students) could potentially operate fume hoods. In addition, 100% of the 142 fume hoods were 40 50 60 70 80 90 100 Dry-Bulb Temperature (°F) ASHRAE Standard 110 field-tested (4L as FIGURE 2 Neutral temperature air-handling system with dual energy recovery wheels.