Apogee Enterprises“ CEO, Russ Huffer, spoke to attendees at Glass Expo Midwest 2010 in Schaumburg, Illinois, about BIPV (building integrated photovoltaics) and achieving zero energy systems. Accordin…
Apogee Enterprises“ CEO, Russ Huffer, spoke to attendees at Glass Expo Midwest 2010 in Schaumburg, Illinois, about BIPV (building integrated photovoltaics) and achieving zero energy systems. According to Huffer, BIPV technology is still ahead of the glazing industry, adding that Apogee, “spent millions of dollars trying to develop solar panels, but [we found] it wasn“t right and that project has been abandoned.” As far as zero energy is concerned, Huffer stressed the importance of understanding the values delivered by these systems. “Why zero energy? Because commercial buildings generate half of all electricity used. Not only that, they are extremely inefficient,” Huffer said, explaining that the glazing industry“s focus will be on zero energy curtainwall and windows. “Let“s simplify the problem. Glass and metal systems transcend, absorb and reflect energy, so a low-E coating is a mirror to long-wave energy efficiency. For most systems this can be calculated and measured very accurately. We know how much energy is coming in on a hot day and leaving on a cold day,” said Huffer. “Solar energy accounts for most heat gain through our systems to the inside of the building; air conditioning is the primary cost for most buildings.” He also pointed out that peak solar energy is about 100 watts per sq.ft.; while on a vertical wall it is about 70 watts per sq.ft. Another critical factor is that of understanding the payback: “Also, if you are called to install [panels] on a roof, find out the life of the roof,” advised Huffer. ” If the BIPV payback is 30 years and the roof has to be replaced every 20 years you are at a loss.” He also pointed out that: “Excess solar energy gain moves us further away from a zero energy wall. During heating we want to reduce heat loss through the systems while utilizing heat gain. “We want the glass to compete for use in zero energy buildings our designs have to compete aesthetically and designs have to compete economically. And the real measure of energy performance is how much is needed to mitigate the heat gain and loss caused by our systems.” Huffer added that zero energy designs should include the cost of sustainably-designed power systems resulting in zero energy wall designs. With regards to mitigating energy systems, he said the added cost of a vertical installation system within the curtainwall is about USD 120 per peak watt. “I recommend keeping them in a green field,” he said, “which will provide a greater payback. A zero energy wall is impossible to do in a flat wall. In order for it to exist new technologies will have to capture and concentrate energy. In the end, I think people will be asking for this, but the technology is still ahead of the industry. These systems are limited in their payback and what they can do,” he added. Huffer went on to say: “All things considered, what we“re already doing, dual-glazed systems, low-E coatings, etc., is better than BIPV. We“re headed in that [BIPV] direction, but we can“t get there with today“s technology because the payback is so long,” he said and added, “PV panels lose 1% of their output every year.”