[RE-wrenches] AC (only) Diversion

Tue Oct 23 01:35:30 PDT 2012

Yes, thermal is convenient, but in my region, it makes no sense as you can
heat the water from the sun without any pv involved.
Anyone who is going to install solar pv already has solar thermal.

I have looked at ice production,  but that would not require diversion. In
that case, there was so much excess that they would schedule the
manufacture of ice at the weekends to use up the power.

The biggest issue is that it is not guaranteed. You might have cloudy days
where there is no excess, so it needs to be non-critical usage.
Something like the production of hydrogen for a fuel cell. In fact that
will likely be a real solution in the new future.

I wrote a blog post on this subject some time ago
http://caribbeanrenewable.blogspot.com/2012/04/what-would-you-do-with-free-electricity.html

On Mon, Oct 22, 2012 at 10:40 PM, Carl Emerson <Carl at solarking.net.nz>wrote:

>  Hi Chris,****
>
> ** **
>
> The most obvious use would be to heat a thermal store.****
>
> ** **
>
> This is a resistive load and very easy to control.****
>
> ** **
>
> I also have a client who would like to use it for irrigation loads.****
>
> ** **
>
> So what is the device you have in mind?****
>
> ** **
>
> Carl Emerson****
>
> Free Power Co.****
>
> Land line +64 9 473 4286****
>
> Mobile +64 22 630 9689****
>
> Email   emerson at freepower.co.nz****
>
> Web   www.freepower.co.nz****
>
> ** **
>  ------------------------------
>
> *From:* re-wrenches-bounces at lists.re-wrenches.org [mailto:
> re-wrenches-bounces at lists.re-wrenches.org] *On Behalf Of *Chris Mason
> *Sent:* 23 October 2012 2:03 p.m.
> *To:* RE-wrenches
> *Subject:* Re: [RE-wrenches] AC (only) Diversion****
>
> ** **
>
> This is something I have pondered a lot as the export tariff here is zero.
> But there is a fundamental flaw in your logic. You are asking what device
> would do this, that's an easy answer. Your real problem is what would you
> use it for. What can this electricity be used for that is worth not getting
> 10c per KWh for it.****
>
> Answer that and the device will be easy.****
>
> On Mon, Oct 22, 2012 at 8:12 PM, Carl Emerson <Carl at solarking.net.nz>
> wrote:****
>
> Hi There,****
>
>  ****
>
> Since no-one has mentioned an ‘off the shelf’ product to achieve AC
> diversion for a grid-tied system, I would like to look at developing one.*
> ***
>
>  ****
>
> I am prepared to put my ideas into the ring.****
>
>  ****
>
> This could be a collaborative effort, are there others who would like to
> participate in this ?****
>
>  ****
>
> If so please contact me off list…****
>
>  ****
>
> Regards
> Carl Emerson****
>
> Freepower Co.****
>
> Auckland NZ****
>
>  ****
>
>  ****
>
>  ****
>
>  ****
>
>  ****
>  ------------------------------
>
> *From:* re-wrenches-bounces at lists.re-wrenches.org [mailto:
> re-wrenches-bounces at lists.re-wrenches.org] *On Behalf Of *Carl Emerson
> *Sent:* 16 October 2012 1:36 p.m.
> *To:* 'RE-wrenches'
> *Subject:* [RE-wrenches] FW: AC (only) Diversion****
>
>  ****
>
> Hi there,****
>
>  ****
>
> Just to clarify, we are talking about a battery-less grid tie system.****
>
>  ****
>
> We want to have the choice to divert the AC available for export to an AC
> load for example a pump or a thermal store.****
>
>  ****
>
> The reason for this is that the tariff for export may be only 10c and the
> unit cost to import 20c.  (net-metering not available)****
>
>  ****
>
> Further to this, the tariff changes depending on the time of day.****
>
>  ****
>
> Financially it is often a better option to use the excess power locally on
> site rather than to sell back to the grid.****
>
>  ****
>
> Is there an off the shelf unit that will sense when the generated power
> exceeds the loads and can divert the power that would have been exported to
> a local load?****
>
>  ****
>
> I have figured out a way to do this cheaply but need to know if I am
> reinventing the wheel…****
>
>  ****
>
> Carl Emerson****
>
> Free Power Co.****
>
> Land line +64 9 473 4286****
>
> Mobile +64 22 630 9689****
>
> Email   emerson at freepower.co.nz****
>
> Web   www.freepower.co.nz****
>
>  ****
>  ------------------------------
>
> *From:* re-wrenches-bounces at lists.re-wrenches.org [mailto:
> re-wrenches-bounces at lists.re-wrenches.org] *On Behalf Of *Drake
> *Sent:* 16 October 2012 1:04 a.m.
> *To:* RE-wrenches
> *Subject:* Re: [RE-wrenches] AC (only) Diversion****
>
>  ****
>
> You could use Morning Star relay driver to control the AC dump load. I
> have one for my system, but have not yet installed it, but have programmed
> it on my computer.  If it works as designed, it should be perfect in
> conjunction with a relay.
>
>
>
> At 04:42 AM 10/14/2012, you wrote:****
>
> Hi there,
>
> Is there an off the shelf low cost product that will divert exported
> energy to a load?
>
> I have put thought into this and have a simple solution but need to know
> if it is worth while marketing it.
>
>
> Carl Emerson
> Free Power Co.
> Land line +64 9 473 4286
> Mobile +64 22 630 9689
> Email   emerson at freepower.co.nz
> Web   www.freepower.co.nz
>  ****
>  ------------------------------
>
> *From:* re-wrenches-bounces at lists.re-wrenches.org [mailto:re-wrenches-bounces at lists.re-wrenches.org<re-wrenches-bounces at lists.re-wrenches.org>]
> *On Behalf Of *Chris Mason
> *Sent:* 13 October 2012 2:17 p.m.
> *To:* RE-wrenches
> *Subject:* Re: [RE-wrenches] AC (only) Diversion
>
> It is called a reverse current relay, use it to to run on a water heating
> contactor when there is current to the grid.
> This is a problem I have struggled with for ages. We do not get credit for
> export so I have been looking for a good use for free electricity, have not
> found one yet.
> On Fri, Oct 12, 2012 at 3:36 PM, Nathan Stumpff <Nathan at arcticsun-llc.com> wrote:
> Wrenches,
>
> We are working on the design for a system where we will be using grid-tied
> wind and solar but will not be able to net-meter the project (we can
> interconnect but the meter only runs one way.) Anything we use on site is
> worth 100%, any production that goes back to the grid is lost forever to
> the customer. What we would like to do is monitor all solar and wind
> production, monitor all usage, and then be able to dump every watt-hour of
> over production as heat, there is plenty of (thermal) storage capacity.
>
> If this were a battery based system I know how I would approach this and
> what equipment I would spec, but so far I am having a hard time coming up
> with a  solution. Anyone have any suggestions for products or strategies in
> this case? Something like an eGauge with programmable PWM relay outputs?
>
> Any thoughts or suggestions are most appreciated,
> -Nathan
>
>
> --
> Nathan J. Stumpff - Arctic Sun, LLC
> NABCEP Certified PV Installer #091209-175
> NABCEP Certified Solar Heating Installer #032412-14
> nathan at arcticsun-llc.com
> Office: 907/457-1297****
>
>
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> ****
>
> ** **
>
> --
> Chris Mason****
>
> President, Comet Systems Ltd****
>
> www.cometenergysystems.com****
>
> Cell: 264.235.5670****
>
> Skype: netconcepts****
>
> ** **
>
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-- 
Chris Mason
President, Comet Systems Ltd
www.cometenergysystems.com
Cell: 264.235.5670
Skype: netconcepts
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