Energy Efficient Schools Improve the Learning Environment
By Phil Kirk
As it appeared in School Construction News magazine
When it comes to construction, renovation and the operation of K-12 schools, it seems that the adage “do more with less” is a way of life. The public is resistant to tax increases. Local and state governments are cash strapped and are often calling for across-the-board cuts in spending. Voters are wary of new bond issues and increasing government debt. All the while, these same groups are demanding improved test scores and graduates who have strong language, math and technology skills to be ready to enter the workforce or higher education programs. Attention to the energy efficiency of the learning facilities is a “do more with less” strategy that can help in balancing both sides of the equation.
LET’S LOOK AT THE MATH
It has been said “you have to spend money to make money.” This might imply that a school system needs to spend more than they currently are in order save money down the road. Although it is not completely false, there are financing options such as performance contracts that can greatly reduce or even eliminate upfront capital expenditures. In addition, many utility providers and some government agencies offer incentives or grants to offset equipment costs. These opportunities may apply to existing school facilities, as well as new construction. This means the school board may not have to ask the taxpayers to write a big check up front to improve energy efficiency on school campuses.
The next budget payoff occurs when every month for the next 15, 20 or even 30 years, the cost of operating the school is less, even in a scenario where the upfront cost is paid through a loan that is tied to a guarantee of predicted energy and operational savings. Because the predictions tend to be conservative, almost always the actual saving exceeds the guaranteed savings.
THE SCIENCE AND TECHNOLOGY BEHIND ENERGY SAVINGS
The development of low-wattage lighting (LEDs and high-efficiency florescent bulbs and fixtures) provides significant reductions in energy consumption. They reduce the amount of energy needed to sufficiently illuminate a space, as well as reduce radiant heat output, a wasted-energy byproduct of incandescent and other forms of lighting. The heat produced by lights can be costly. Every therm of heat produced by a light bulb has a corresponding unit of energy consumed to produce it. In addition, this radiant heat may need to be removed from the space to provide a consistently comfortable temperature.
On the heating and cooling side of the equation, many of the fundamentals are based on the theory that energy cannot be created or destroyed, it can only be changed from one form to another. To that end, engineers have concentrated efforts on how to precisely control the energy-transformation process, as well as employing the energy that already exist all around us.
Computer technology has been integral in creating energy efficient buildings. One application is the development of variable frequency drives (VFD) for pumps and motors. This technological advance means that the equipment no longer needs to operate at fixed speeds, but can continually adjust speed to meet the exact demand of the moment. As a result, VFDs have made it economically practical to repurpose ambient/naturally occurring heat. It is now affordable to extract the heat from the air on the sunny side of a building and move the thermal energy across the building to be released on the shady opposing side. This can greatly reduce overall demand for heating and cooling from chillers and boilers. Following this same concept, geothermal (extracting and expelling heat into the ground) is becoming a practical alternative to the fan-based cooling tower.
Other equipment has also taken dramatic efficiency leaps. Boilers are achieving 80 and even 90 percent efficiency. Chillers in the past 25 years have decreased energy consumption by nearly half, from .8kW/ton to .45kW/ton of cooling capacity. Further enhancing these savings are individual room controls and facility-management dashboards. Environmental systems can be programmed to turn on, off and adjust up or down based on human input, day and time, as well as the monitoring of environmental factors including occupancy. For example, a gymnasium may: not need heating when empty; need cooling during a basketball game with the bleachers packed with excited fans; need moderate heating for an active physical education class; and need full load heating when students are in a sit-and-listen mode wearing their gym clothes. Moreover, facility administrators and maintenance personnel can remotely monitor both demand and operations, overriding functions when necessary. These systems also provide advanced warning of potential problems, reducing maintenance costs.
Chemistry is another contributor to greater energy efficiency. Advances in refrigerant technology have not only made them safer for the environment, but also expanded their capabilities. For example, thermal energy can now be stored. This allows for electrical-demand load shifting from peak-use hours to late night. What this often means is the kWh rate to operate the building is reduced. There are even some incentives from the utility companies to help in the purchase of thermal-storage equipment. An example of thermal storage is ice-bank technology. This process runs a chiller at peak performance during the lowest rate times to freeze liquid filled tanks. Then, during the heat of the day when rates are at their highest, the refrigerant providing the cooling to classrooms is circulated through the tank until cooled to the necessary temperature. As a result, chillers can often remain completely dormant during the top rate times of day.
Desiccants are a second popular energy-efficiency option in modern heating, ventilation and cooling (HVAC) systems. In many climates, dehumidification is a necessary part of the HVAC process, as moisture stores energy. Therefore if the air is too moist, a larger amount of cooling activity is required to achieve the desired decrease in ambient temperature. In humid climates, conventional dehumidification systems, with fans and compressors, require considerable energy to operate. By installing desiccant fields in air circulations systems, optimum humidity levels can be maintained passively by absorbing or releasing moisture into the air without many of the mechanical system of traditional dehumidifiers.
With all of the options available to manage a building’s internal environment, one of the most powerful tools to improve energy efficiency is building information modeling (BIM). Architects and engineers now have the ability to input a full range of building specifications into programs that will run energy consumption scenarios. This helps in the decision process for building materials, as well as lighting and mechanical-system equipment.
IMPROVED READING, WRITING AND THE ART OF PERFORMANCE
Between 2000 and 2009 more than 20 studies were published on the relationship between school infrastructure and classroom performance. There were only two that did not indicate a correlation. In the 18 others, attendance, test scores, behavior and graduation were all lower in facilities that have a condition ranking low or poor. A study of Texas high schools found a 4-9 percent difference in science, English and math test scores and a 4 percent difference in graduation rates between students in schools in worst/best condition.1 We know that if a student can’t see or hear well it is difficult for them to learn. Therefore, the first considerations in school construction and improvements need to be how well lit is the learning space, as well as classroom acoustics and background noise often a byproduct of heating and cooling systems. In addition, children who are uncomfortable because a room is hot, cold or stuffy can be difficult to teach due to the psychological distraction that comes from discomfort. Along with many of the options already discussed, the act of pretreating (heating, cooling balancing humidity levels and filtering) at the fresh-air intake may go a long way in helping students focus.
In fact, an American Civil Liberties Union report indicates the top four criteria, in order, demonstrating impact on student achievement are as follows:
- Human Comfort – i.e., temperatures within the human comfort range as regulated by appropriate HVAC systems
- Indoor Air Quality – i.e., appropriate ventilation and filtering systems, also regulated by appropriate HVAC systems
- Acoustical Control
The report goes on to say that there is extensive research demonstrating a strong correlation between a comfortable temperature range and student achievement. Air-conditioning, ventilation, and heating systems therefore should be given the first priority.2
It is clear, and not much of a surprise, that student performance can be improved by creating best-in-class learning environments. What is surprising is that it costs less to upgrade or build schools with best-in-class environmental systems than it does to operate existing facilities with condition rankings low or poor.
Phil Kirk is Chairman Emeritus of the North Carolina State Board of Education. He has served as Chief of Staff for North Carolina Governors Jim Holshouser and Jim Martin, as well as United States Senator Jim Broyhill. He served twice as the North Carolina Secretary of the Department of Health and Human Services. In 1970, he became the youngest State Senator in North Carolina history at that time and chaired the two largest bond campaigns in North Carolina history, which provided more than $6 billion for the UNC system, K-12 schools, community colleges, and highways. To contact Phil Kirk, call 919. 232.5900 or e-mail firstname.lastname@example.org.
- Blincoe, J. M. (2008). The age and condition of Texas high schools as related to student academic achievement. (Ed.D., University of Texas at Austin).
- Glen I. Earthman (2004). PRIORITIZATION OF 31 CRITERIA FOR SCHOOL BUILDING ADEQUACY. (American Civil Liberties Union Foundation of Maryland).