Jim Wheeler 2016-07-02 02:10:09
Higher HVAC efficiencies? It’s easy! In my column in the May issue I pointed out our industry is in the process of setting higher minimum cooling efficiency standards for the year 2024. And in typical fashion — in my opinion — our American HVAC industry leaders are trying to keep everything about the same. Meanwhile, most offshore manufacturers already are shipping systems here with minimum cooling efficiencies that are at least two points higher than our current legal minimums. We can expect their minimums to keep growing right up to and beyond 2024 when they will leave our domestic manufacturers in their wake (more jobs going offshore). So the position American manufacturers are taking is not only foolish, it is customer-service suicide and it’s time to speak up! How difficult is it to raise minimum efficiencies? It’s a lot easier than you may think. Where do you start raising efficiencies? How about with the compressors, the fan motors, the indoor coils and the outdoor coils, because there have been recent technical developments in each of these areas. Compressors: The last time domestic manufacturers claimed they would have trouble meeting the (13-SEER) minimum, all most had to do was change to scroll compressors, tighten up the refrigerant metering and expand the coil sizes. And compressor manufacturers have continued to improve the efficiencies since then with such small changes as adding internal unloaders that turn single-capacity compressors into dual-capacity compressors. Yes, these do currently cost a bit more, but that will change as their market grows. There also are new types of compressors being developed. Manufacturer Nortek (Maytag, Frigidaire, etc.) has shown us even rotary compressors can be used more efficiently in domestic cooling systems in the 1-to-5-ton range. Also, there’s a new type of compressor that is currently under development that eliminates the friction losses inherent to crank-type drives because the piston simply is a magnet that is driven by an electromagnet. Fan motors: The one thing foreign manufacturers have shown us is that variable-speed DC motors are much more efficient and provide more comfortable air distribution. Yes, they require electronics to drive them, but the electronics are becoming far less expensive since those companies that use such devices don’t seem to have a problem competing pricewise against our old standard PSC motors (thankyou, Mr. Tesla). Coils (indoor and outdoor): Over the past decade, we’ve seen some great innovations in coil designs and there still is some room for improvement here. Of course, all a coil has to do is transfer the heat energy from the internal refrigerant to the air passing through the coils — so there is a limit to how efficient we can make them. Yet there are enhancements that can be made to the type of tubing used, which can improve heat transfer. And improving heat transfer isn’t the only area where there is room for growth. There still are pressure losses that can be reduced in the refrigerant circuits, equal refrigerant distribution problems that can be addressed and equal air distribution problems that also can be improved. Don’t let those who oppose progress lull you into thinking that improving the energy efficiency of cooling systems simply and inexpensively can’t be done. It most certainly can with just a little more innovative engineering. And isn’t innovation what makes our country strong? We shouldn’t allow others to bypass us because we’ve become too satisfied with the status quo! JIM WHEELER is an award-winning journalist who has worked in various positions in the HVACR industry since the early 1970s. His articles have been appearing every month since October 1986. Contact him at firstname.lastname@example.org.
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