Any facilities manager or data center operator knows that cooling accounts for a large chunk of annual operating expenses. It only makes sense, then, to understand how to build and operate an energy efficient cooling system.
The good news is there’s a painless way to educate yourself on the issue, with the free online course from Schneider Electric’s Energy University, “HVAC Efficiency and Equipment Optimization.”
As the course makes clear, efficiency depends not just on how efficient your HVAC equipment is, but on the way it’s all set up. As the course says, “A system designed with efficient equipment that is used inefficiently makes for an inefficient system.”
You’ll learn some of the key design elements to promote efficiency, such as how to correctly choose and size equipment. The course also explains why large, central plants are no longer necessarily more efficient than a number of smaller, distributed units and why it’s no longer necessary to oversize equipment to deal with expected peak loads.
The course explains how to deal with variable loads, meaning changes in night-time vs. day time temperature and humidity as well as varying loads depending on issues such as whether buildings are fully occupied or virtually empty.
You’ll learn some valuable equations that will help you more fully understand the capacity and energy efficiency rating of any given HVAC unit. Probably you’re aware that, like most any large appliance, HVAC systems have an energy efficiency ratio (EER). But have you any idea how that ratio is derived? In the course, you’ll walk through equations that show how to calculate EER as well as SEER, or seasonal energy efficiency ratio.
Similar to SEER but applied to heating effects is the Heating Seasonal Performance Factor (HSPF), which is the efficiency of an electric heat pump. Heat pumps are, in effect, an air conditioner that can run in reverse, to bring heat from outdoors to inside the building.
There’s also a detailed discussion of COP, which stands for coefficient of performance. You’ll learn how to convert the compression power of an HVAC unit, in both kW and horsepower, and its cooling capacity in tons into a COP value. That’s an important consideration because a higher COP indicates a device will provide more cooling for less power consumption. HSPF evaluates the average performance of a heat pump over the course of a heating season or an entire year.
The course examines a number of the components that make up an HVAC system, such as heat transfer equipment and cooling towers, explaining the function of each component and what kind of efficiencies to expect from each under varying scenarios. There’s also a discussion of air-side economizers and how they can save energy by using outside air to cool buildings under certain conditions.
If you’ve got any involvement in cooling a building or data center, or simply want to better understand what makes for an efficient HVAC system, invest less than an hour of your time and check out “HVAC Efficiency and Equipment Optimization.” You’ll find it in the College of Energy Efficiency at Energy University.