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Archive for the category “thermal solar”

There is Still Potential in Thermal Solar

[] – Solarthermie: Effizienter durch neue Techniken

Solar Air Collectors

Early December, outside temperature 6C/43F. Two simple air collectors and ventilators. Max output temperature: 62C/143F

[] – Solar air collector project in northern Germany

Still waiting for the first solar air collector project where the black absorber back plate consists of a black solar panel. The collector should be constructed as such that the glass/acryl cover can be removed in the spring and put back again in the autumn to avoid too high solar panel temperatures during the summer. Special construction absorber with window screen.


Siebdruckplatten: Materialstärke (Seitenwände) 21 mm – 35 €/m²
Materialstärke 9 mm (Rückwand) – 20 €/m²
Acryllack, Dose mit 125 ml – 4,99 €
Aluschiene, 1 cm x 3 cm x 200 cm (2mm), 2 Stück –
Aluschiene, 3 cm x 3 cm x 200 cm (2mm), 1 Stück –
Aluschiene, H – Form
Schrauben V2A, 4 x 25
Schrauben V2A, 3,5 x 16
Schrauben V2A, 4,5 x 45
Fiberglasnetz, 1m x 3,40 m
Acrylglasscheibe (Gewächshaus) 70 x 160 cm
Computerlüfter 12 V, 120 mm, 115 m³/h

Acryl cover

The end result

Some data:

01.03.2013 – complete sunny day
Collector temperature: 39,5 °C

Hybrid Solar

panel-thermoSolar thermal-electric hybrid

volther-powertherm-180wConventional thermal solar collector

In densely packed cities in overcrowded north-western Europe, space is the real scarce commodity, more than money. The consequence is that if this scarce (roof) space is used for solar energy, preference is usually given to solar panels over thermal solar collectors. In fact, when we visited the 2014 Munich Intersolar exhibition, there were hardly any producers of solar thermal collectors present.

It is premature however to write-off thermal solar completely. If sun rays hit a solar panel, ca. 15% is converted into electricity and the rest is lost in heating up the panel, which degrades performance. The idea of hybrid solar is to use the same (scarce) surface for both electricity and heat:

A solar hybrid panel has two energy outlets: one for electricity and one for hot fluid, utilizing nearly all solar energy.


[] – Photovoltaic Thermal PVT
[] – Solartherm Hybrid PV
[] – Volther Hybrid PV-T Panels
[] – Volther PowerVolt PV-T Hybrid Collector

hybrid-solar[source] Robust two-edged sword

DIY Solar Collector For Domestic Heating

build a solar heater 01 cover jpg[source]
You typically are living in a home that has been built years ago, in a time when no energy problems existed. Your energy bills are rising all the time and you have a number of unused square meters on your roof or in your garden and you are thinking how to utilize them. No off-the-shelve solutions are available so you have to come up with something yourself, like all the people showin the videos below have done. No doubt your own collector is going to be different than all the ones presented here. Nevertheless, before you begin designing your own, it is good to pick up ideas and learn from mistakes others have made.

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Transpired Solar Collector

A conventional solar thermal collector in essence consists of a glass cover, a black absorption plate and an insulated back cover. If however there is large blind facade available, it may be considered to eliminate the expensive glass cover and compensate the loss of thermal efficiency by an enlarged collector area. These Unglazed Air Collectors or Transpired Solar Collectors are typically used to heat ambient air in commercial, industrial, agriculture and process applications. According to wikipedia:

It is typically the most cost-effective out of all the solar technologies, especially in commercial and industrial applications, and it addresses the largest usage of building energy in heating climates, which is space heating and industrial process heating.

[] – Solar air heat

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World’s Largest Thermal Solar Plant Online in Arizona

280 MW. World’s largest parabolic trough array with thermal storage. Constructed by Spanish group Abengoa. More spectacular thermal solar projects are underway in Arizona, putting this technology back on the map in competition with photovoltaics.


Passive Solar Space Heating

A relatively cheap way to reduce your fossil fuel bill is to apply passive solar heating. In general it comes down to a glass plate covering a black plate or wall. Sunlight is absorbed and heats the air between glass plate and black absorber. The warm air rises and is lead into the building at the top. Air to be heated is lead into this space from the bottom. No moving parts necessary.

[wikipedia] – Solar wall
[wikipedia] – Trombe wall

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