Residential

Thank you for considering addition of a solar domestic hot water system. Please review the site selection of this website to determine the viability of your site for solar. To summarize, the collector area should be relatively free from shade, and a southern orientation, and good access to mechanical systems.

Once the choice has been made to install a solar hot water system, the next step is to determine system type and size. In this section, we'll look at basic system types (open direct, glycol and drainback systems), collector types (flat plate and evacuated tube, collector mounting options (flush, tilt and roof integrated), and sizing considerations.

For an excellent free source of information on solar system types, sizing, ball park cost and paybacks, please see:

 www.solar-estimate.org

SYSTEM TYPE: OPEN DIRECT, GLYCOL OR DRAINBACK

If you live in an area that seldom, if ever freezes, an open direct solar hot water system would be appropriate. Open direct systems are common only in tropical areas. Where there is even a slight chance of freezing weather, you must select either a glycol or drainback solar system to provide freeze protection..

Below are diagrams of a glycol system and the SHEM Simple Drainback system. In terms of system cost, installation and operational complexity and overall system performance, the SHEM Simple Drainback system is the obvious choice.

(See Dare to Compare for detailed comparison)

Compare the SHEM Simple Drainback system (right) to a glycol system. The SHEM Simple Drainback system not only has fewer components, but the components are superior in size and configuration. For example, the heart of all SHEM systems are massive, spirally augmented copper heat exchangers. Please compare the SHEM system and any of its components to any other system on the market. You'll see that no other system comes close to SHEM's level of heat exchange capability.

Installing a drainback system may not be practical, due to inability to drainback or other site considerations. In that case, glycol systems may be an appropriate choice. Glycol systems can be used with either flat plate or evacuated tube collectors. For simplicity, we'll examine use of the SHEM Simpledrainback system with Solene Aurora flat plate collectors.

SIZING THE DRAINBACK TANK- 80 OR 120 GALLON

Hot water useage is a function of family size and hot water use patterns. According to Energy Information Agency (DOE), a fair rule of thumb for hot water average hot water consumption is:

1 Person = 34 to 45 gallons/day
2 People = 43 to 58 gallons/day
4 People = 75 to 87 gallons/day
6 People = 105 to 122 gallons per day

Another useful rule of thumb regarding domestic hot water use is 20 gallons per day for the first person, 15 gallons per day for the second, and 10 gallons per day for each additional person, then round up to increment of 10. Consider a family of 5: The predicted use would be 20 + 15 + 10 + 10 + 10 = 65, round up to 70 gallons. Using this rule of thumb, an 80 gallon tank should suffice.

For most homes, an 80 gallon solar tank will be adequate, especially if some of daily use occurs during daylight hours. The main purpose of the tank is to store btus. If energy will be used only in the morning, then a larger tank is warranted. However, if some of the enegy use is during daytime hours, the 80 gallon tanks should suffice.

NUMBER AND SIZE OF COLLECTORS

For most of the continental U.S., the issue of number and size of collectors can be reduced to one choice: Single 4' by 10' or two 4' by 8' solar thermal collectors. A single 4' by 10' collector would provide 40 square feet of surface area, while two 4' by 8' collectors would provide 64 square feet of surface area. (Not considering radiant needs.)

Below is a diagram of the output of a single 4' by 10' collector and two 4' * 8' collectors given demand for 80 gallons of water at 120 degree F in Kansas City, MO. Please note the output characteristics. Closer calculation revealed that the single collector in Kansas City provided a 65% solar fraction, while two 4' by 8' collectors yielded a 74% solar fraction. In summer months, both systems overproduce. During the cold of winter, both systems underproduce. In the spring and fall, two collectors will outperform the single collector.

4' by 10' Collector Output (40 Square Feet) Compared to Two 4' by 8' Collector Output (64 Square Feet)

Select the following link to view a comparison between single 4' by 10' and two 4' by 8' collectors in Kansas City MO, Sacramento CA, Charleston SC, Austin TX and Philadelphia PA..

Please also see the link to Solar Fraction:

WHY SOLENE AURORA

Simply put, the Solene Aurora is an excellent collector in every respect. And, it's made in the USA! Several features make the Aurora collector an excellent choice. First and foremost, they are an excellent producer of btus. Please see the comparison below. Second, the Aurora is an extremely well made collector. The manner in which they are constructed creates a solid assembly which is made even more solid by addition of a mid-collector support bar. For multiple collector arrays, installers find that manifolds ALWAYS fit exactly together. And, the Aurora is a nice looking collector!

Please contact your solar thermal dealer for more details on your new solar hot water system!