Solar Evacuated Tubes

Posted by admin | | Sunday 15 February 2009 8:40 pm


Our solar evacuated tube collectors offer reliable hot water heating in all climates. Designed for areas where it is warm to extreme cold, the evacuated tube technology provides additional insulation around their absorbers to retain heat absorption, and are not affected by outside air temp. They also absorb available sunlight from 360 degrees. setofevacuatedtubessolar2

Their modern design is coupled with convenient installation methods. The evacuated tube series collectors are assembled in modules making it easy to have flexible job times. The first step begins with sizing your application and roofing area, next you assemble the frame and connect all required piping. No need to worry about stagnation with these collectors. Install the evacuated tubes after you have installed the mounting hardware and have pressurized the system. We estimate an average time of 1.5 hour to assemble each collector.

It all depends on your location:

In the sunny middle of the country, one Sq Ft of our Solar Evacuated Tube Panels will produce an average 290,000 Btu’s per year at an initial panel cost of $38 per Sq Ft. On a bright winter day they will produce an average of 1,400 Btu’s per Sq Ft per day.

In the sunny middle of the country, one Sq Ft of our Solar Flat Panels will produce an average of 294,000 Btu’s per year at an initial panel cost of $32 per Sq Ft.  On a bright Fall or Spring day they will produce  1,418  Btu’s per Sq Ft per day. If you are in an area where near or below freezing temps are normal for the heating months, then  Solar Flat Panels will not produce enough energy to match the Evacuated tubes. Solar Evacuated Tubes would be the proper and efficient Solar Panels for that climate.

Flat Panels are more efficient in warmer climates than Evacuated Tube Panels. Flat Panels are affected by outside air temp and cold wind, and Evacuated Panels are not.  When you need less than 130-degree water, FP’s are the best in non-freezing areas.

Evacuated Tube Panels are more efficient in warm to sub-freezing climates, as they are not affected by outside air temperature or cold wind, and absorb available sunlight from 360 degrees. They are designed for DHW needs and/or house heating, and commercial structural heating needs with water temps between 120 – 190 degrees F.

Better Performance + Better Price = Better Value: In independent testing by the SRCC (Solar Ratings & Certification Corporation) SunMaxx Evacuated Tube Solar Collectors have proven themselves to be a better value than the leading competition. Our SM-30 Solar Collectors delivered higher performance  (up to 42,000 + BTU/Day) than the competition, and our low prices mean you get more BTU per $ spent. This means DogStar Solar customers experience a rare combination: the best product at the best price.

Evacuated Tube Solar Collectors operate on the basic principle of using the light from the sun to heat liquids. Our solar energy powered hot water tubes then store the water in a solar hot water tank just like your current hot water heater. The image below shows the process that takes place within an Evacuated Tube as it is heating water.

How Evacuated Tube Solar Collectors Work

Evacuated Tube Solar Collectors:

This is about Evacuated Tubes ( heat pipe), U-Tubes, and Thermosyphon ( direct flow).

Evacuated Tube Solar collectors come in 3 different types. There are Heat Pipe style collectors, U-Pipe style collectors, and Direct Flow style collectors. Evacuated Tube Heat Pipe style solar collectors are the most popular type of Evacuated Tube Solar Collectors. The U-Pipe Evacuated Tube Solar Collectors have a key advantage over Heat Pipe Models as U-Pipe Solar Collectors can be installed vertical or horizontal, allowing for more flexibility in your system design and installation, and they can be mounted flat on the wall of your house if needed. The Thermosyphon Kits are the low stress, inexpensive, simple design built with Direct Flow Evacuated Tube Solar Collectors. Contact us and we can explain and answer all your questions.

Evacuated Tube Solar Collectors are useful in every climate and location, they are happy down to -40 Degrees F.  The vacuum sealed tube is freeze proof, maintaining high temperatures in bright sunlight, while the outside temperature is freezing. This outstanding performance in colder climates give Evacuated Tube Solar Collectors a decided advantage over Flat Plate Solar Collectors in mid to northern locations.

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Evacuated U-Tube Solar Collectors:

SM- U Pipe 20 tubes

U-Pipe Evacuated Tube Solar Collectors are smaller and more compact than SunMaxx Heat Pipe Evacuated Tube Solar Collectors. While the two collectors have nearly identical efficiency ratings, there are several key advantages to U-Pipe Evacuated Tube Solar Collectors. These Include:

  • Extremely Low Price                                                                  u-pipe-working-pic
  • Additional Installation Versatility
  • Compact Size for Tight Installation Locations

SunMaxx U-Pipe Solar Collectors cost less than SunMaxx Heat Pipe Evacuated Tube Solar Collectors, which are already one of the industry’s most affordable lines of solar collectors. The main point here is that U-Pipe Collectors can be installed perfectly vertical or horizontal, allowing for a wider variety of installation options, which allow these solar collectors to be used where other collectors can not be used, such as on the top of a flat roof building where tilt mounting is not an option due to space limitations,  as an overhang from buildings where there is no roof space to mount the solar collectors, or flush vertically on a wall.

Each U-Pipe Evacuated Tube Solar Collectors includes:   u-pipe-pic

  • 30 Revolutionary SunMaxx Evacuated Tubes
  • 30 U-Pipe Style Copper Heat Pipes
  • SunMaxx 30 Face Frame w/Assembly Hardware Kit
  • SunMaxx 30 Flush Mount Hardware for Pitched Roofs
  • 10 Year SunMaxx Limited Warranty
  • Customer Support

Assembly Time: A single SunMaxx 30U Solar Collector can be assembled and installed in about 1.5 hours.

Comparison of SunMaxx Heat Pipe Vs U-Pipe Evacuated Tube Solar Collectors:

Test Models:  SunMaxx-30 Heat Pipe, and SunMaxx-30U-Pipe
Testing Report:  Solar Keymark Certification Testing

Model SunMaxx-30U SunMaxx-30
Collector Type
U-Pipe
Heat Pipe
Aperture Area 2.67 m2 (28.74 ft2) 2.79 m2 (30.03 ft2)
Conversion Factor (efficiency (no)) 0.650 0.734
Heat Transfer Coefficient (a1) 1.585 W/(m2K) 1.529 W/(m2K)
Temperature Dependent Heat Transfer Coefficient (a2) 0.002 W/(m2K) 0.012 W/(m2K)
Typical Power Output/Collector
Tm – Ta (K)
@ 400 W/m2 @ 700 W/m2 @ 1000 W/m2
@ 400 W/m2 @ 700 W/m2 @ 1000 W/m2
10
649 1172 1693
772 1387 2001
30
562 1083 1510
650 1264 1879
50
469 990 1510
490 1105 1719
Power Output (W/m2 – Aperture Area) based on 1000W/m2 Irradiance 634 W/m2 of Aperture Area 717 W/m2 of Aperture Area
Power Output (BTU/h/m2 – Aperture Area) based on 1000W/m2 Irradiance 2163 BTU/h/m2 of Aperture Area
201 BTU/h/ft2 of Aperture Area
2446 BTU/h/m2 of Aperture Area
227 BTU/h/ft2 of Aperture Area
Total BTU/h 5923 BTU/h 6824 BTU/h
BTU/h/$ Invested (Value of Collector) BTU/h/$ 4.76 BTU/h/$ 3.90

It is clear from the results that the conversion efficiency of SunMaxx Heat Pipe Evacuated Tube Solar Collectors is better than that of SunMaxx U-Pipe Evacuated Tube Solar Collectors.

However, in pure dollar value – BTU/h/$ invested – SunMaxx U-Pipe Solar Evacuated Tube Solar Collectors deliver a higher energy value because of their extremely low price and high performance ratings.

In particular, U-Pipe Solar Collectors are the perfect for installations where the Solar Collectors will be mounted flush (flat) on a zero-pitch (flat) roof, or in a vertical orientation on the side wall of a building.

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