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Flat Plate vs Evacuated Tube. Hollis Fitch – Cinco Solar, 100% ET San Antonio, TX “Here in Texas, our biggest concern is wind and hail. ET collectors are better in both circumstances, since they let the wind through in hurricane zones and offer replacement of tubes from hail damage”.
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Flat Plate vs Evacuated Tube
Hollis Fitch – Cinco Solar, 100% ET San Antonio, TX • “Here in Texas, our biggest concern is wind and hail. ET collectors are better in both circumstances, since they let the wind through in hurricane zones and offer replacement of tubes from hail damage”
Thomas Isaac – Techsun Solar, 100% FP San Marcos, TX • “In Texas, as most of the US, we have the triple headed monster for solar hot water- overheating, scale, and freezing. FP collectors work best. There is no contest.”
Installation Costs? • Installation of Headers • Individual tubes Vs • Substructure, • Collectors placed
Flat Plate • Pro’s • Flexible for DHW and hydronic applications • Less expensive, value per sq/ft is higher • Night Sky Re-radiation possible with FP
Night Sky Cooling Night Sky Re-Radiation
Flat Plate • Pro’s • Flexible for DHW and hydronic applications • Less expensive, value per sq/ft is higher • Night Sky Re-radiation possible with FP • 15-70° angles available • 10yr warranty but 30+ yr life expectancy • Flexible to install for direction and inclination • Glass can be replaced if damaged • Designed, packaged, sold by Lochinvar!
Flat Plate • Con’s • Slightly lower performance in cold cloudy weather
Evacuated Tube • Pro’s • Low heat loss due to vacuum • High temp output, over 210° • Better performance in cloudy weather • Individual tubes can be replaced if damaged or vacuum is lost • Not affected as much by winds as it passes between tubes
Evacuated Tube • Con’s • No direct temperature measuring • Lowest inclination is at 30° • Difficulty shedding snow and ice
Evacuated Tube • Con’s • No direct temperature measuring • Lowest inclination is at 30° • Difficulty shedding snow and ice • Night Sky Re-Radiation won’t work • Greater overheat potential • Fragile-1.6m glass won’t withstand hail over 1”
Evacuated Tube • Con’s • No direct temperature measuring • Lowest inclination is at 30° • Difficulty shedding snow and ice • Night Sky Re-Radiation won’t work • Greater overheat potential • Fragile. 1.6m glass won’t withstand hail over 1” • Expensive • Tubes don’t have to break to lose vacuum • 10yr warranty but 10-15 yr life expectancy
Y-Intercept - .739 Slope - .722 btuh/ sq ft/ F
Efficiency Collector Temperature – Ambient Temperature
Solar Industry MagazineApri 2009 • Flat Plate versus Evacuated Tube: Which performs better? “The results, measured in btuouput, confirmed the conclusion of the results cited in an earlier study. Once again, the flat plate system outperformed the evacuated tube system on an annual basis.”