As laboratory designers and operators strive toward making their labs more energy efficient, several approaches can go a long way toward accomplishing the goals of bringing down both energy usage and costs. Efficient vacuum supply can play a part.
In this post, we’ll outline a few of the most important strategies to consider when operating an energy efficient laboratory.
New construction
Architects who pay careful attention to building design will be able to significantly limit heat gains and losses. Leveraging technology like exterior shading, high-reflectivity window films, low energy lighting and insulated door and window frames can reduce the amount of energy it takes to keep the lab at its ideal temperature, offering building owners significant cost savings. As heating, cooling and air circulation account for as much as 60 percent of the energy usage in a lab building, evaluation of the contribution of energy efficient technologies – such as chilled beams, heat recovery systems, automated fume hood sash control, electronically monitored and controlled variable air volume systems and ductless (filtered) fume hoods – should be high on the designer’s list.
Existing buildings
Even without the possibilities open amid new construction, there may be significant opportunities to reduce energy use in existing buildings. Simple measure like use of task lighting and LED lighting instead of overhead lighting offers significant savings, as will shutting the sash of fume hoods when not in use. The Caltech Energy Assessment for Laboratories (CEAL) report highlights the energy demands of plug loads in labs – energy used to operate equipment. The most energy intensive devices are used for temperature control, specifically freezers, furnaces and ovens, and incubators. Defrosting freezers regularly and turning off incubators and ovens when not in use can yield material savings with no investment.
Lab vacuum systems
Immediately behind the thermal control equipment are vacuum pumps, both in terms of frequency of use and contribution to plug loads. The biggest energy consumer for lab vacuum is often a central vacuum pump that produces vacuum 24/7, even though the building is typically unoccupied in the 70 percent of the time represented by nights and weekends. In-lab plug loads for vacuum materially increase the energy use. While there may relatively few options for reducing energy use by specialized vacuum used for instrumentation like mass spectrometers, even these pumps may show energy savings by the simple step of changing to a lower viscosity pump oil. Consult your instrumentation supplier before taking this step.
For general purpose vacuum, using dry (oil-free) diaphragm pumps will usually produce energy savings compared with common oil-sealed pump, as will the use of pumps with variable speed motors. These pumps are often more corrosion resistant, and require less service. As the maximum pumping speed is needed mainly to create vacuum for an application, and much less is needed to maintain the vacuum, variable speed pumps can reduce energy use for vacuum production by as much as 90 percent. (The variable speed control can also enhance process control for better scientific results.) Local vacuum networks help cut operating costs without taking up valuable lab space.
Local vacuum networks can take the energy savings a step further. Local vacuum networks combine the vacuum performance advantages of individual pumps with the convenience and space-efficiency of vacuum from the bench or fume-hood vacuum turrets of a central vacuum system. This approach produces the vacuum on demand in the laboratory using quiet, dry pumps to serve numerous users at once in teaching and research labs. Compared with 24/7 vacuum production by large central pumps, here too energy savings can reach 90 percent. Combined with variable speed vacuum pumps as network pumps, total energy savings of networked vacuum can exceed 90 percent.
Whether you’re designing a new laboratory altogether or simply modifying your existing lab space, incorporating these energy-saving technologies into your plans can have a significant impact on the amount of energy, and cash, you spend.