[RE-wrenches] Tube solar collectors

[Dave Click]

Yes they do:
http://www.solyndra.com/Products/More-Electricity

-------- Original Message --------
Subject: Re: [RE-wrenches] Tube solar collectors
From: Joel  Davidson <joel.davidson at sbcglobal.net>
To: RE-wrenches <re-wrenches at lists.re-wrenches.org>
Date: 2009/7/21 09:46

> Hello Kelly,
> 
> Thanks for the feedback. Does anyone know if the Solyndra CIGS modules 
> collect light from the backside?
> 
> Joel Davidson
> 
> ----- Original Message ----- From: "Kelly Keilwitz, Whidbey Sun & Wind" 
> <kelly at whidbeysunwind.com>
> To: "RE Wrenches listserve" <re-wrenches at lists.re-wrenches.org>
> Sent: Monday, July 20, 2009 11:15 PM
> Subject: Re: [RE-wrenches] Tube solar collectors
> 
> 
>> Joel,
>>
>> We frequently will orient tube collectors on east or west facing roofs 
>> with
>> very good results. However, pointing a solar collector toward the 
>> south will
>> always produce more energy, as we all know that the greatest solar 
>> energy is
>> concentrated around noon.
>>
>> The choice of whether to tilt comes down to efficiency, cost, and 
>> aesthetics
>> - and sometimes overheating issues. With a tube system care must be taken
>> not to oversize the collector in proportion to the tank. If a customer 
>> wants
>> to maximize heating throughout the year I recommend a larger collector
>> tilted steeply toward the winter sun angle. This not only maximizes 
>> winter
>> production but, more importantly, attenuates summer heat gain.
>>
>> It's interesting to note that, as Apricus tubes have the collector 
>> surface
>> circumferentially, they will collect heat from the backside (a 
>> significant
>> factor during northern summers).
>>
>> Another design factor is that the heat pipes must always maintain a slope
>> for heat transfer. Thus, tilting up on the east or west-facing roof is
>> necessary if the tubes are to be oriented N-S.
>>
>> -Kelly
>> Kelly Keilwitz, P.E.
>> Whidbey Sun & Wind, LLC
>> Renewable Energy Systems
>> NABCEP Certified PV Installer
>> 987 Wanamaker Rd,
>> Coupeville, WA 98239
>> PH & FAX 360-678-7131
>> sunwind at whidbeysunwind.com
>>
>>
>> On 7/20/09 8:09 AM, "Joel  Davidson" <joel.davidson at sbcglobal.net> wrote:
>>
>>> Hello Kelly,
>>>
>>> I saw your website photos (nice work). Do you think that tubes 
>>> oriented (1)
>>> east-west would and (2) flat would perform as well as your tilted
>>> north-south tubes?
>>>
>>> Joel Davidson
>>>
>>> ----- Original Message -----
>>> From: "Kelly Keilwitz, Whidbey Sun & Wind" <kelly at whidbeysunwind.com>
>>> To: "RE Wrenches listserve" <re-wrenches at lists.re-wrenches.org>
>>> Sent: Monday, July 20, 2009 12:12 AM
>>> Subject: Re: [RE-wrenches] Tube solar collectors
>>>
>>>
>>> All,
>>> Apricus ET's have a cylindrical absorber surface, which are 
>>> significantly
>>> better at capturing low angle of incidence energy. I have both a 
>>> Thermomax
>>> (with flat collector plate internal to the tube) and Apricus 
>>> collector in
>>> parallel on my own home and see significantly better temperatures 
>>> early and
>>> late in the day on the Apricus collector.
>>>
>>> IMO, ET's have a distinct advantage in our cool, windy, and low-snow
>>> environment (northern Puget Sound).
>>>
>>> Kelly Keilwitz, P.E.
>>> Whidbey Sun & Wind, LLC
>>> Renewable Energy Systems
>>> NABCEP Certified PV Installer
>>> 987 Wanamaker Rd,
>>> Coupeville, WA 98239
>>> PH & FAX 360-678-7131
>>> sunwind at whidbeysunwind.com
>>>
>>>
>>
>>
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