photovoltaics help needed please

[anthony wall]

hi all 'i am looking to install a p v system to augment my electric supply my problem being that i know next to nothing about solar installations or more specificaly the equipment needed to put together a workable system, as you may know i live in thailand now and finding the equipment is going to present its own challenge but i don't know what to look for. the electric over here is 230volts 50 herts and i am looking for a system to produce maybe 1 kw, i don't yet know weather to have a battery storage system or a direct link system i am looking for direction as i know there are some very knowlageable members using s m c so any help is going to be much appreciated-thanks for any help you can give :confused::confused:

[Larry Edgerton]

I was hoping that there was some discussion on this subject as it is an idea I am toying with myself. I want a system that will power the fan on my wood furnace as damage can happen to the firebox in a power outage and maybe a few lights.

Larry

[Dan Hintz]

Unless you're simply looking to lower your power bill during day use, you'll want some form of energy storage. Otherwise, the cells will do you no good as the late evening hours hit.

[anthony wall]

hi dan ,i had thought of storage but the info that i can find points to it being a very expensive option and as all my shop time is during daylight hours and a lot of my electric consumption is in daylight hours i was thinking of my first installation being without storage to see how it pans out

[Mike Henderson]

Many watt hour meters will run backwards when power is sent from your home to the grid. If your meter works that way, you will be using the grid as a storage device (put power in during the day, take it out at night).

Mike

[Dan Friedrichs]

Anthony - I've had some formal training in the design of PV systems, so I'll take a stab at this.

Let me say that, if you were in the US, I'd advise you against installing any type of PV system, if your end goal was simply to reduce the cost of electricity (and assuming you were not going to benefit from any government/utility subsidy). Even in the US, without subsidies, it's difficult to design a system that pays for itself.

What is the purpose of the installation? Is it to provide redundancy against failure of the local grid, or are you just trying to save money?

What sort of sunlight do you have access to? Can you aim the panels such that you get good exposure for a significant portion of the day? Even a little bit of shading of the panels will significantly reduce energy output (ie - even if a tree is casting a shadow that shades only 5% of your panels, you may see a 50% drop in energy production, as a byproduct of the series connections typically used to boost voltage output from arrays of cells)

You can either build a grid-tied or off-grid system. For a grid-tied system, you need panels and an inverter (which converters the DC from the panels to the AC produced by the grid). As Mike said, if your utility provides "net metering", you can run the meter backwards and get "paid" for excess energy you produce. But if the grid is down, it may not be easy to disconnect for backup power.

If you do an off-grid system, you would have panels, an inverter, a bank of batteries, and potentially a battery charger (if the inverter does not include that function). You could include a transfer switch to allow you to use the grid or not. Batteries are typically "gel cell"-type "deep cycle" (or "marine") 12V batteries. They need to be replaced every 5-ish years.

Ultimately, unless you have some very odd source of super-cheap panels, I doubt you will find it cost-effective. Even if you are simply seeking redundancy, a generator is likely much, much cheaper. If you do decide to go with a PV system, please consider having it professionally engineered - many people erroneously think that they can DIY this sort of thing, and the fact is, the cost of the engineering will pay for itself by producing a system that is markedly more efficient and productive than anything a non-expert could construct.

[anthony wall]

hi dan,i have a couple of reasons for wanting a pv system the first being that i would like to save money on my monthly bills but the main reason is that we own a piece of land that we plan to build a house on and my wifes 5 sisters also want to build houses on the land which is close to their home village.the pv system on our own house would be used as a learning experience also we have unshaded sunlight for around 12 hours almost every day of the year even in the rainy season the clouds usualy appear after dark. if i buy around 2000pv cells i can get them for less than50 cents each which sounds like a reasonable price ? the other project of building the 6 houses we would like to go off grid if possible so storage would be a must

[Dan Friedrichs]

So is your primary motivation to reduce electricity costs, or are you also interested in being energy independent?

You don't want to buy raw solar cells - you want to buy "panels" of cells preconnected in a weatherproof enclosure.

Are there any government or utility incentives to installation of a PV system? Those incentives could be worth a huge portion of your return-on-investment.

What is your present electricity cost?

[anthony wall]

dan it appears that there are no government incentives to installing pv's over here,on the new houses we would like to be completely energy independent and also plan to install some type of wind turbine to go with the pv system as the land is in the mountains in central thailand benefiting from the usual mountain breeses

[Mike Henderson]

If you want to be energy independent, you're going to need a fairly expensive system, with a significant amount of batteries. And you're going to have to find ways to reduce your energy usage significantly.

Mike

[anthony wall]

hi mike,yes we understand that we will have to reduce our usage somewhat to be totally self sufficient but we will still have grid connections to fall back on

[Mike Henderson]

Okay, I misunderstood. You said you wanted to be completely energy independent in your previous post.

Mike

[John Shuk]

Many watt hour meters will run backwards when power is sent from your home to the grid. If your meter works that way, you will be using the grid as a storage device (put power in during the day, take it out at night).

Mike
That may not apply in Thailand.

[Mike Henderson]

That may not apply in Thailand.
It may not but if they use the older mechanical watt hour meters, they probably do run backwards. Back when those meters were designed, no one ever thought of a customer, especially a single phase customer, feeding power back into the grid. And if they didn't put extra things into the meter to prevent it from running backwards, it probably will run backwards.

Mike

[anthony wall]

well our meter is the older type mechanical type so hopeing it will go backwards