PV / thermal hybrid panels [RE-wrenches]

[Tom Lane]

Look up critical threshold  in solar thermal collection  and you will=20
understand why unglazed thermal colletors do not have a prayer when it=
 comes=20
to space heating or hot water heating over 115 f even in the summer .=20
gator tom
----- Original Message -----=20
From: "troy" <taharvey at heliocentric.org>
To: <RE-wrenches at topica.com>
Sent: Sunday, June 15, 2008 4:35 PM
Subject: Re: PV / thermal hybrid panels [RE-wrenches]



I haven't worked with sundrum, but I have done performance forensics
on a Dawn solar system and been involved with another PVT system.
Compared to glazed systems these systems can perform very poorly. In
the case of the Dawn solar system, it performs very poorly even
compared to unglazed collectors (1/8 the efficiency with a steep
efficiency decline).

The key issue is the adsorption and emissivity of these surfaces.
Unless they are coating the PV glass with a Low-E coating, its not
going to be great. A typical NOCT for a PV panel is 113=B0F under FULL
sun (1000 W/m^2) and 77=B0F outdoor temp. Obviously not too hot, even in
good conditions. While they produce lots of BTUs, they often don't
produce it at a useful temperature. In the winter at most locales, the
production will practically be zero, unless you can have large preheat
tank for the 60-70=B0F water that you'll make. In the summer they can
produce a good bit of moderate temperature water. The question is is
it cheap enough to make it worthwhile?


Troy Harvey
---------------------
Heliocentric
801-453-9434
taharvey at heliocentric.org


On Jun 4, 2008, at 5:34 PM, Kirk Herander wrote:

>
>
> Hello,
>
>
>
> There is a company called Sundrum which integrates a solar thermal=20
> collector
> on the backside of PV panels. As advertised, the thermal panels  absorb=
=20
> heat
> for transfer to DHW and also keep the panel cooler for higher power=20
> output.
> I think they have sizes for Sanyo and Evergreen modules. Anybody=20
> experienced
> with this or any similar products? Thanks.
>
>
>
>
>
> Kirk Herander
>
> Vermont Solar Engineering
>
> 802.863.1202
>
> fax 802.863-7908
>
> NABCEP(tm) Certified Solar PV Installer
>
> Xantrex Certified Dealer Charter Member
>
> NYSERDA-eligible installer
>
> VT Solar Incentive Program Partner
>
>
>
>
> [Non-text portions of this message have been removed]
>
>
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