by Dominick Guarino
As the United States continues its quest for greener living, pressures continue to mount on the HVACR Industry to deliver systems that consume less energy and leave a smaller carbon footprint.
One way government will likely continue to exert pressure is to force manufacturers to make equipment with higher SEER ratings. The increase to the minimum 13-SEER rating was just the beginning. Recently, we’ve seen a push for even higher regional standards, and there’s already talk of the next “bump” in minimum federal efficiency requirements.
The problem is we’re disregarding two important factors: the physics of current direct expansion (DX) air conditioning systems, and the exponentially diminishing returns from higher SEER ratings with current technology.
As manufacturers push to achieve higher SEERs, they flirt with a fine line in DX physics by achieving the ratings under very precise conditions. The result is equipment that is much more sensitive to the conditions of the systems they’re connected to.
It’s a Bell Curve
Picture a bell curve with the top of the curve as the sweet spot where the rated efficiency is achieved. Many factors affect efficiency on both sides of that curve. Efficiency degradation can be caused by too high or too low refrigerant charge, too high or too low air flow, duct system leakage and radiant gains or losses, restrictions, improper sizing, poor air distribution design, and so forth.
With lower efficiency (8 and 10 SEER) equipment, even if these factors weren’t perfect, the equipment itself operated within a fairly normal range (wider bell curve).
Higher efficiency equipment (13 SEER and up) is much less forgiving (bell curve looks more like an arrowhead). If refrigerant charge isn’t right on, efficiency drops like a rock. If the system is oversized and short cycles, the equipment never runs long enough to reach its sweet spot in terms of rated efficiency. If airflow is too high or too low, heat transfer is greatly reduced, affecting delivered efficiency.
Dehumidification is also a factor in higher efficiency units. If charges and airflows aren’t near perfect, the system’s ability to dehumidify will drop significantly.
The bottom line is there is more evidence than ever that there’s a lot more to be gained from proper installation and getting the “system” working right than from producing higher SEER boxes.
What’s The Answer?
As an industry we need to stand up to government and let them know they’re focusing on the wrong things. Instead of mandating more efficient boxes, government should create better incentives for homeowners and contractors to make systems work right and achieve delivered efficiencies. This would reduce consumption and emissions far beyond what we could ever achieve with a higher SEER condensing unit.
Mandating delivered efficiencies in installed systems, similar to how they’re mandated for the boxes, would also be a HUGE mistake. Just take a look at the disaster Title 24 legislation has created in California.
If the Air conditioning, Heating and Refrigeration Institute (AHRI) manufacturers, distributors, and contractors would present a united front and tell the Department of Energy (DOE) that enough is enough, we may just get on the right path to deliver efficiency.
If manufacturers didn’t have to spend their research and development efforts and budgets just trying to keep up with every volley of government demands, they could invest in further developing breakthrough cooling technologies. Some such technologies already exist, but are barely being explored, yet perhaps they could take air conditioning to the next level.
In the meantime, with the right contractor and consumer education and incentives, the installation side of our industry could take the lead and achieve tremendous gains in delivered efficiency. Today we have the technology to better understand and measure delivered efficiency. If good contractors rise to the challenge and learn how to achieve real improvement, not only will everyone win – we might just get government off our backs – at least for a little while.
Dominick Guarino is chairman & CEO of National Comfort Institute (NCI), (www.nationalcomfortinstitute.com) a national training and certification organization teaching Air Diagnostics and Balancing, Carbon Monoxide Safety, Combustion Analysis and Tuning, Performance- Based Selling, and more. Email him at [email protected] or call NCI at 800/633-7058.