Photovoltaic in ecogîte: small question energy storage

[elephant]

Christophe: it is undoubtedly profitable, since we make "professional" power stations on this principle, but I fear the cost of the turbine.
(if it exists in this power range)

grelinette: great, your lodging, but I won't be happy until you give me:
1) your peak KW power
2) your "residual" hot water consumption: to properly wash everyone's dishes (large) people, you must need a few lites, anyway?

[Grelinette]

Thank you for all your comments, but the basic question remains:
How to use or store usefully the electricity produced in summer which is lost and which will be very useful as soon as the sun does not shine as much?

This question would surely interest most owners of PV panels.

According to you, Christophe, an alternative solution would be a cyclic solar battery! What?

That said, Christophe, I have read your reasoning, but basically don't forget that we use an energy that is abundant, free and unused, which largely re-balances the profitability of the system.

To come back to the cost of such an energy storage installation in the form of a water reserve, that does not seem so high to me and for an "experimental" and educational site like the one in question.
This is a point that can also be the theme of a very interesting experimental site project for groups welcomed (without going back on the usefulness of a water reserve in a site very subject to fire risks ).
For example, recently the association had a green roof installed by groups and received subsidies for this site.

So the necessary equipment:

- The reservoir : derisory if we give it a try with an above ground pool (which is easily found on the internet). Besides, the association has many partners (http://educ-envir.org/~loubatas/partenaires.htm) and can easily get one or get a grant to buy one.

- The pump to convey the water at height: either buy it or combine a two-pass system (automatic solenoid valve type) which uses the borehole pump which currently supplies the eco-lodging.

- Piping : 32mm garden hose with a few fittings should suffice.

- The turbine: it is indeed the sensitive point!
I started on the assumption that we can use a generator identical to that of a wind turbine.
The generator would be placed in a dry place, driven by the turbine connected by a mechanical system (belt, chain, gimbal, etc.). Since water has a much higher inertia than water and wind hazards and irregularities are excluded, the system should be simpler and more reliable.
Of course, there remains to buy or manufacture the turbine!
(I even imagined that the generator could be both coupled to the turbine AND to a wind turbine above because the reserve would be installed in height therefore more subject to the wind ... but this is another technical aspect to solve) .

- ... : I surely forgot other elements and I count on you to remind me of them!

In response to elephant, here are some details on the installation that I found on the site of the association:
(note that the association has yet installed new PV panels on the roof specifically for drilling).
44 m² of photovoltaic solar panels produce electricity (4200 watt-peak), with an LPG gas generator as a backup.
21 m² of solar water heaters making it possible to produce domestic hot water and to heat the building by a "direct solar floor", with a gas boiler in addition.
The drinking water supply comes from a borehole 100m deep equipped with a submersible pump. Photovoltaic solar panels allow this water to be pumped "over the sun": when it is sunny, the pumping operates to fill a 15000-liter storage tank. The electricity produced is not stored. When there is no sun, water is drawn from the cistern. The borehole has only a limited flow, which is why we should all be vigilant so as not to waste it. The pumping system is equipped with meters making it possible to measure the quantity of water pumped per hour, as well as a totalizing meter.


I look forward to your comments and suggestions! [/ Url]

[Christophe]

Christophe: it is undoubtedly profitable, since we make "professional" power stations on this principle, but I fear the cost of the turbine.
(if it exists in this power range)

Yes of course it is profitable but for millions of m3 pumped generally pumped in "natural" structures and this to have a reserve in the event of a peak (what is the cost of a blackout)?

They have been doing this in the Lac Noir / Lac Blanc resort in the Vosges for 80 years!

According to wiki:

A hydroelectric plant was built there between 1928 and 1933 by René Koechlin. This is the first Pumped / Turbine Energy Transfer Station (STEP). Lac Noir is connected to Lac Blanc (120 meters higher) by a pipe that allows the production of electricity by turbines at peak hours, alternating with recharging Lac Blanc, which is higher, by pumping during off-peak hours.. It produces a power of 80 MW.

Zavé seen from the plan is an alternator-motor (you know what is supposedly an innovation of the car manufacturers with the alternator-starter ... the honest never hurt, especially in science!

Grelinette's problem is not at all the same ... we are talking about storing, say, 1 kWh ... and comparing 2 solutions: batteries or pumping / turbining ...

[chatelot16]

pump and turbine I could do them without problem

the power of this turbine pump can be quite low

where it goes is the volume of water to store: if it is necessary to build the tanks it costs more than lead-acid batteries for the same energy

pumped storage is profitable when you just build dams to make huge, almost natural reservoirs

using a deep borehole as a low reservoir is an idea but the turbine pump must be at the bottom of the borehole a submersible pump could be used as a turbine

but I hope it is forbidden: it is a blow to send underground room water stored on the surface in an unclean basin: therefore miserably polluting the water table

[Grelinette]

I don't understand why you don't like my tank solution with one or more large above ground pools!

It's simple and inexpensive, and the largest are over 50 m3!

Well, say it, if it's because there aren't enough bathers, I add more

Otherwise, there is also the possibility of digging a large hole and covering. This allows for an even larger open pit tank. This system is widely used in agriculture and allows to have a reserve of several hundred m3 and which also collect rainwater!


To be more precise and move forward on this project, let's start with the hypothesis of a 100 m3 reservoir located 20 m high:

1) What type of turbine (diameter, power) would it take to replace the voltaic panels that are stranded in the sun?
2) What would be the simplest assembly to carry out such an installation?

nb: a quick search on the net allowed me to find this: http://www.fao.org/docrep/010/ah810f/AH810F12.htm

[Christophe]

Well, it's not that we don't like Mr Linette! This is because I doubt that it will be more econological and energetically efficient, for "low" volumes, than "beast" solar batteries ...

[Grelinette]

... I doubt that this is more econological and energetically efficient, for "low" volumes, than "beast" solar batteries ...

In the eco-gite there is already a whole room entirely dedicated to the storage of batteries (it's impressive! ).

Not only is there the wear of the batteries, then the pollution at the time of recycling, and that only pushes the problem because even if we doubled the number of batteries, the problem would arise again: all the batteries would be quickly full and solar panels would still produce for nothing!
(in addition I believe that an authorization is necessary to have the right to store a large number of batteries especially in a place of reception of the public).

There is also the experimental side which may lead to interesting alternative and complementary solutions.

[Christophe]

A solar battery in normal condition of use = 10 to 12 years of service life.

Will your pump, your tarpaulin, your turbine ... etc etc ... last as long?

What about the initial investment?

Take up my reasoning above on the energy potential of pumped water ... I don't know if you had read it?

[chatelot16]

calculates the volume of water required and compares with the price of the batteries

every time i did this calculation i realized that pumped water storage was more expensive than batteries

useless to choose the type of turbine: starts by making the theoretical calculation with a perfect turbine of output = 1

take your volume of water and your drop:
potential energy in J = water weight in N x height difference in m

as it is especially the tanks which are expensive it is necessary to have a very big difference in level to hope for a certain profitability

[Grelinette]

Well ... if I understand correctly, storing energy in the form of a water reserve is not that simple and so profitable!

So I come back to the basic problem:

How to make an eco-gîte with 35 places over-equipped with solar panels completely self-sufficient in energy, knowing that:

a) the energy produced by the solar panels and stored in batteries does not allow to meet the consumption of the lodging all the year, in particular in peak period, especially if the sun is missing

b) in summer, the PV panels operate at maximum but at a loss (production> consumption) and the batteries are full

c) there is already an impressive stock of batteries which it seems difficult to increase further (regulations, place, price, ...)
Maybe change the current battery model to more efficient ones?

Finally, what suggestions would you make so that the gîte does not need to use the emergency diesel generator when electricity is lacking? (burning GO is a paradox for an ecological building!)