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Improve Student and Building Scores with Energy Efficient HVAC Equipment
Scores have always been an important subject in California’s K-12 public schools. Administrators and parents alike look to student test scores as a barometer of the quality of education the schools are delivering.
Well, test scores aren’t the only kind of assessment that matters with schools these days. K-12 schools have been increasing their building energy scores by embarking on energy efficiency projects like upgrading their heating, ventilation and air conditioning (HVAC) systems. Administered by organizations like the Collaborative for High Performance Schools (CHPS)1, ENERGY STAR®2 and LEED (Leadership in Energy and Environmental Design) for Schools3, these programs assign scores that rate the schools in terms of their efficiency in a variety of areas.
And as it turns out, schools achieving higher building energy scores can have a positive impact on student test scores as well. By installing more energy efficient equipment, school administrators are enhancing student comfort, healthiness and attention span, which can ultimately give test scores and education outcomes a lift.
While other areas such as proper lighting also can enhance the learning environment, for the purposes of this blog article, let’s concentrate on the main components of HVAC equipment.4
Ventilation: Stepping up in class
Superior indoor air quality can help ensure a healthier and higher performance learning environment for students and staff, and the choice of ventilation equipment plays a big role in the quality of the indoor air. Proper ventilation with outdoor air is a key component for good indoor air quality in schools and classrooms, since indoor air may be two to five times more polluted than outdoor air, and there are large populations of children who may be more susceptible to indoor pollutants than the general population.5 Energy recovery ventilation systems have been identified as equipment that potentially can address technical and financial issues associated with outdoor air ventilation in schools.
At a minimum, an optimum energy efficient school ventilation system should provide adequate fresh air intake, prevent growth of mold from unwanted moisture accumulation and keep the noise level in classrooms to a minimum. Best practices for ensuring this include:
- Installing an outdoor air measuring station that modulates the outdoor air damper and return damper, which is relatively simple and ensures sufficient fresh air supply
- Ensuring that all HVAC system air supply diffusers, return registers and outside air intakes are clean and unobstructed, and filters are replaced regularly; these measures improve ventilation rates and should not raise energy consumption
- Checking air economizers regularly to ensure that their dampers are functioning properly; dampers that are stuck open could be letting in too much outside air, and ones that are stuck closed won’t provide the benefit of free cooling
- Installing demand-controlled ventilation systems in spaces with occasionally high occupancy, such as auditoriums, gyms and cafeterias; however, be careful not to reduce outdoor air below the recommended minimum
- Making sure the air supply registers and return grills are the proper size and placed in the right areas so that air can flow into the classrooms without making unnecessary noise, which can be a distraction to both teachers and students
Heating and cooling: A tempered approach
With heating and cooling systems accounting for more than half the energy that schools use, making sure the most efficient and correctly sized system is in place is critical. To that end, the first step is determining what kind of HVAC system is right for the school, based on the area’s climate and energy rate structures. For example, evaporative cooling is especially effective in warm, dry climates. Thermal storage is appropriate where demand charges are high or time-based rates are used.
In most climates, the boiler is the largest single piece of energy-using equipment in a school building—a good fact to keep in mind. As a result, it is critical to keep detailed records of boiler energy use and maintenance. Although sophisticated software is available to analyze energy consumption, simple data analysis, such as comparing energy data with that of similar buildings, can also be useful.
With regard to cooling, most maintenance recommendations apply to all types of air conditioning systems found in schools, including package systems and classroom unit ventilators. The general cooling efficiency of the air conditioning system should be checked every three to five years or following a change of the HVAC system. Cooling efficiency can be found based on measurements of airflow, temperatures and electrical demand. There are commercially available measurement systems to help automate the process and help diagnose problems. Airflow and refrigerant charge measurements should be the first priorities, but efficiency estimation may not cost much more if an automated measurement and diagnostic system is used.
Once the right HVAC system is in place, maintenance is critical. Best practices include:
- Cleaning burners and air conditioner coils
- Checking ducts for leaks at joints and flexible connections
- Inspecting hot and cold duct and pipe insulation and seals for inadequate insulation
- Verifying and adjusting refrigerant charge on packaged air conditioning systems
- Monitoring, calibrating and repairing enthalpy controls and mixed-air controls to maintain efficient operation
- Checking, adjusting or replacing fan belts
- Lubricating all bearings and other friction points, such as damper joints
- Inspecting fan wheels and blades for dirt accumulation and cleaning them as required
- Adjusting or repairing packing glands and seals on valve stems and pumps
- Ensuring that no oil or water enters the main air supply for the control systems
If it’s time for your K-12 school to consider an energy efficiency upgrade to improve the learning environment, download PG&E’s free eBook, "How to Get the Best Results from a Lighting or HVAC Project" to learn how to get started.
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