Opportunities for Laboratory Energy Conservation
There are large, untapped energy savings opportunities in university lab buildings. Strategies to reduce energy in labs include behavioral change strategies and technical opportunities.
Behavioral Change Strategies
Behavioral change opportunities abound in the university laboratory setting. The options range from sharing research space; locating equipment like refrigerators centrally; purchasing resource efficient lab equipment; recycling within the lab and many others. These options all have energy, cost and space implications. The enormous energy intensity of the fume hood made it a logical place for us to start our investigation. Addressing user management of fume hoods is not new, but can prove to be an effective way to save energy, money and increase user safety.
Case Studies: Behavioral Change Opportunities for Laboratory Energy Conservation
FAS, CCB Department
In the fall and winter of 2005-6, CERP ran its first "Shut the Sash" contests in the Naito Laboratory and Mallinckrodt-Hoffman Link (Shair lab) to help people get in the habit of closing their sashes. We tracked each hood to see which room decreased its exhaust - that is, had closed sashes - most over 2 months, compared to baseline data. Educational materials, emails, and visits to group meetings accompanied contest publicity and updates. Together, the labs decreased hood exhaust by about 21%. Since last year, we have been tracking venilation exhaust rates in three more labs that had switched to VAV (Variable Air Volume) fumehoods. If sustained over the course of the year, energy conservation efforts in Naito, Shair, Liu and Jacobsen labs could save close to $100,000!
Duke University
Duke University achieved significant behavior-related savings in its labs with variable air hoods. Brewer reports on the case study of one 344,000 square foot building with 140 fume hoods. An educational campaign consisted of a) contacting the lab operators on an individual basis, b) discussing the impact of lowering the sash and c) providing an education handout and placing a magnetic reminder on hoods (Brewer, Harris and Thomann 2003). In order to test their hypothesis that: "incremental, quantifiable energy savings could be realized through good laboratory practices after air handling systems had been optimized was tested" they split the labs in one building into an "experimental" and a "control group," with the experimental group receiving the education noted above. With a 35% rate of user compliance (i.e. only 35% of users complying with the 'please lower the sash' request) saving are roughly $30,000 (2003).
Technical Opportunities
Technical opportunies include heat recovery, user-based controls, variable air volume, low-flow hume hoods, night set-backs on ventilation and light when the building is not in used or only marginally used, and the installation of central building management system (BMS) to control all systems.
Case Study: Night time Set-Backs for Laboratory Facilities
In 2001, the operations department at the Harvard School of Public Health (HSPH), led by Daniel Beaudoin, Manager of Operations, Energy & Utilities, investigated how laboratories were being used, with the goal of reducing unnecessary energy consumption.. Laboratory occupant data was gathered, through an hourly head-count of laboratory use at nights and on weekends. Security guards took the count during routine rounds. What they found, shown in Figures 1 and 2, was that on average, there were fewer than two people in any individual lab between 10pm and 6am. On weekends, occupancy was even less.
As a result of this study, the proposed action aimed to institute a new HVAC schedule to reduce system use from 168 to 109 hours per week. The exhaust would be maintained at all times, to ensure the building's negative pressure, but the supply was reduced. The new schedule in three of HSPH's buildings would be Monday to Friday, 6 a.m. to 11 p.m. and Saturday and Sunday 6 a.m. to 6 p.m. Researchers can schedule off-hours lab time. This technical solution requires virtually no capital investment, and returns roughly $330,000 in annual utility savings from steam, chilled water, and electricity. See Figure 3 for a breakout of these savings.
Figure 3: Energy Savings for Three HSPH Lab Buildings with Night Set-Back
Case Study: High Performance Laboratory Renovation Project at HSPH
Currently, the Harvard School of Public Health, led by Daniel Beaudoin, is in the process of implementing a complete gut renovation of 9,000 gross square feet of laboratory spaces in three separate areas: on the second floor of Harvard School of Public Health Building One, in the basement and on the first floor of Building Two. Overall, there have been seventeen low-flow, bi-vortex fume hoods (link to description and links?) to be installed, at a savings of $3,000 for each of these fume hoods, for no additional cost, giving savings of over $50,000 annually for fume hood use.
On the 2 nd floor of Building One, there will be eight fume hoods throughout a series of labs on that floor (see the floor plan in Figure 4). One lab room within this 2 nd floor renovation represents an important experimental opportunity to challenge current guidelines regarding air changes per hour in laboratories of this type. This one lab will have 1,700 usable square feet and host two low-flow, bi-vortex fume hoods. Unlike the rest of the space, which is built to operate at rates above 8 air changes per hour, this one lab will be built to operate at 2.6 air changes per hour, although the ducts will be large enough so that it can also operate at 8 air changes an hour or more. The 2.6 ACH was arrived at as a result of designing the space with a fume hood as the sole source of air to and exhaust from the lab - the lab does not have general room air or general room exhaust. If the guidelines were followed that suggest from between 4 - 15 ACH, certainly it would have been necessary to add additional general room air.
In this space, ceiling hung fan coil units will supply supplemental cooling. A total volatile organic compound (VOC) sensor will be attached to the return grill in this space and connected into the building automated control (BAC) system. The VOC sensors will be programmed for local and remote alarm notification (audible & visual). This alarm will be triggered if the measured VOC rate exceeds a safe level. At that point, operations personnel will be notified, and if it is found that air exchange levels need to be increased, this will be possible.
Harvard's Environmental Health and Safety department has conducted a hazard assessment for each of the laboratories based on their individual chemical inventories and laboratory standard operating protocols (SOP's) provided by end-users. Funding is being sought to further study and compare the two spaces - that space within the recent renovation operating at over 8 ACH and that space operating at 2.6 ACH. This clearly is intended to challenge lab air change rate standards and guidelines (discussed more in the next section - and listed in Table 1) which, as noted by the American Conference of Governmental Industrial Hygienists as well as the authors of the ANSI / AIHA Z9.5-2003 standard, are not an appropriate way to design containment systems. The authors of ANSI / AIHA Z9.5-2003, note that ".air changes per hour is not the appropriate concept for designing contaminant control systems. Contaminants should be controlled at the source."