LG300N1T-G4 -- T for Transparent?

[DanKegel]

Well, bifacial panels are a different beast, of course it's going they'll need to be installed a little differently.
Vendors differ in how well they communicate the difference.
The best so far is Prism Solar, whose design guide http://www.prismsolar.com/pdf/Design_guide.pdf
is backed up by serious data, http://ieeexplore.ieee.org/stamp/sta...number=7387697
But LG has a youtube video, https://www.youtube.com/watch?v=uzpmRKLdPrU
which does try to get the point across -- mount it higher, above a bright surface, for best results.

Installers are, in my sample size of one, completely unprepared for this.
I expect after a few successful installs show how to do it right, and get written up in industry rags with sufficient detail, they'll start getting the idea.

[ncs55]

That LG video clearly references ground and ground mounts repeatedly, it does give some other non standard applications. Does not reference close to roof mounting though. I think it is pretty clear what they are representing.

[DanKegel]

How much irradiance do you think the underside of an array parallel to and 6 " off a roof gets ? A clue: not much.

Right. Who's advocating installing the LG panels that way? LG certainly isn't; their video https://www.youtube.com/watch?v=uzpmRKLdPrU shows how to do it right.

[J.P.M.]

J.P.M. is assuming the worst way the panel could be marketed is how it will actually be marketed.

There's some precedent for this -- see the awful HyperX marketing -- but he's jumping the gun here, I think.

Having been a peddler paid on commission for the first 10 or so years of my working career, I may just have a slightly more realistic opinion than some about why and how things are marketed, and what motivates people to do things. I don't like all - probly a lot - of the ways the game is run, but I don't get much say in that. I deal with it like I find it and see it.

if someone thinks companies are in this for honesty and altruism, or that people can't be manipulated, or someone doesn't understand the temptation to shade reality, they are, IMO only, naïve and a sitting duck.

[DanKegel]

Sure, shady characters abound. But that's what reference checking and good sense are about.

Let's put it this way: LG's bifacial panels are likely to be a useful tool, in the same way a gun is. Should Smith and Wesson be considered evil just because some resellers are acting immorally?

[ncs55]

J.P.M. I was around and active when this all happened in the past, so I understand where it could go. But, enough is enough. We are all in business to make money yes but not every company is as unscrupulous as you are touting. You are lumping all of us in one bag and I personally take offense to that reference and pre judgement. You are just wasting valuable forum space with a negative view of what could be, how stupid people are, and pissin me off in the process.

[J.P.M.]

I see what he is saying, but to reject an improvement in tech is very closed minded. I see that type of thinking a lot in here. The only BS I see here is J.P.M.'s comment. There are a lot of applications. No matter how the past modules were marketed. Look at the LA convention center with all of the unisolar arrays mounted on a bright as hell white roof. (over 6000 laminates when I was there testing them) Using these modules on tilts would reduce the amount of space needed for the inverters on that flat roof. I have worked on that roof for unisolar to determine why the initial install was not performing. You go blind up there without eye protection and it would be a perfect solution.

To be clear, I'm in no way rejecting improvements in product quality and innovation. A pretty good portion of my engineering career was involved in such things.

My issue is with what I see as somewhat deceptive marketing to gain an advantage, perhaps an advantage in public perception only in that folks will see or imagine superior performance where it may come only at the expense of off-standard application and construction requirements. It's using people's solar ignorance in an attempt to gain any such marketing advantage that such ignorance can enable.

Bifacial's a good idea - if for no more cost, so much the better. But it better be little or no cost if it's being marketed to the solar ignorant, because that's what the enhancement will amount to for most any common residential application most of those folks are probably, in their ignorance, assuming.

Question: Are the panels on the LA convention center horizontal or tilted ? I suppose I could look it up. I ask that you indulge my laziness.

[ncs55]

Its long beach convention center sorry, and they are flat installation of Unisolar PVL Laminates, there was 6000 of them give or take. You can see them on google earth.

[DanKegel]

Haven't seen such unwarranted negativity since, oh, his last rant

[ncs55]

good comic relief thanks for the laugh.

[Willaby]

haha, just gave a thumbs up - like; anyone else?

[J.P.M.]

Haven't seen such unwarranted negativity since, oh, his last rant

In the spirit that one snarky comment deserves another: Unwarranted is a matter of opinion, as is, IMO only, the practical worth of most of your opinions and cherry picked attachments with respect to R.E. that seem to substitute other's opinions for the one's you won't, don't or can't get on your own, and then, seem to imply they have the cloak of absolute truth to them simply because they are written and they reinforce what you seem to hold as the immutable truth.

In any case, thank you for the vote of confidence. I'll give it all the consideration it's due. I'm sure you reciprocate the courtesy.

As you have noted in the past - don't like what I or anyone writes - use the ignore button. I mostly use my informal ignore button with your stuff. That has the advantage of allowing me to call B.S. on some of your more egregious brain spoor, which, I'd do more of if I wasn't so lazy.

[DanKegel]

Bifacial's a good idea - if for no more cost, so much the better.

The pricing I saw from one uk site:

204 lg300
221 lg300 black
228 lg300 bifacial
245 lg315
250 lg320

So, halfway between price for 300 and 320.

That seems pretty reasonable.

[azdave]

My issue is with what I see as somewhat deceptive marketing to gain an advantage,

Welcome to Marketing 101.

[J.P.M.]

Welcome to Marketing 101.

Yup. No spoor. Except I been there for close to 50 years, some of that time as the bartender.

[ncs55]

I called my suppliers this morning to see about price and availability here in CA. They said look for them by 3red quarter this year and no pricing yet.

[DanKegel]

thanks!

[J.P.M.]

The pricing I saw from one uk site:

204 lg300
221 lg300 black
228 lg300 bifacial
245 lg315
250 lg320

So, halfway between price for 300 and 320.

That seems pretty reasonable.

To reiterate, I have no issue with the cost, or for that matter, from what I've seen LG's quality.

It's the B.S. innuendo and the poor information that is, IMO, misleading and deceptive. To say, write or imply that bifacial schemes can improve output by 20-30% or possibly more under some unidentified time frames - from periods of hourly to yearly or anything in between, and also without some serious discussion of what type and how severely off common sensibilities and construction the surrounding reflective environment and its possible and likely necessary modification costs to achieve what are, as far as I can know from both some knowledge of the science involved as well as a lot of work on radiation enhancement techniques and schemes, with some of that in an academic environment, very unlikely to happen without some pretty serious changes from what people have come to expect in terms of extra $$ construction cost and appearance. (Sorry for the run on sentence.)

Such successes in enhancement as implied by the LG advertising paint a rosy but incomplete portrait, with only the LG panels in it. The rest of the family that costs $$ is missing. The purported enhancements in possible output come at a price, both in common aesthetics and time/$$. The raw product - the panel may cost the same or less. However, any output enhancement that utilizes changes in panel design are probably more costly in terms of both construction costs and aesthetic sensibilities which are usually not easy to monetize. Those costs are quite likely enough to make such designs cost ineffective. Since most folks have less than a sound footing on calculating cost effectiveness, I'm not real positive about a better outcome in calculating the modified cost effectiveness or the added total cost for using bifacial panels.

As a SWAG, I'd also (and charitably) guess that any enhancement achieved is somewhat positively proportional to the cost of off the standard modifications necessary to achieve such modifications, but perhaps not linear with say 10 % enhancement adding more than 10 % to the total cost.

In any reasonable configuration that looks like what most folks have come to recognize, a 20% or more enhancement in annual output is, IMO, unrealistic. 10% is kind of a stretch as well and would probably, even if possible, look pretty funky.

Since the P.O.A. irradiance on the back side of a panel that's, say, 6" from a roof and parallel to it will be close to zero, I'm quite sure any possible enhancements from a bifacial design will be the same, and = = zero. How many people do you think understand that statement ? My guess is few. And so, as a result of their ignorance, the great unwashed masses will see 30% enhancement for no more $$ per the adverts., and get reeled in based on their ignorance and usual slick but B.S. marketing. Caveat Emptor.

As for tilting a panel or array - an almost essential feature to utilize the attributes of bifacial panels - aside from the aesthetics and practical design considerations such a design would entail, the incident radiation will be a bear to calculate, even for the most simple configurations of the surrounding reflective surfaces.

The incident radiation will be a mix of diffuse and beam, with the beam coming from perhaps many sources, some accidental, some natural or coincidental, and some planned. The diffuse portion of the backside irradiance will be either scatter from diffuse reflecting surfaces, terrain, masonry, etc., or sky diffuse which will be mostly backscattered - that portion being the smaller portion of the mostly forward scattered sky diffuse irradiance. See any decent text on radiation heat transfer - and mostly the part about "view factors" or "exchange factors" for some idea of the scope of the problem and why the irradiance on the backside of an equator facing panel or array is usually quite small and in any case quite difficult to even estimate.

Bottom line, all my opinion only:
1.) Based on experience, education and some common sense, IMO, it is probably not cost effective to utilize the output enhancement bifacial panels may make possible.
2.) Such utilization may require modifications to the surroundings that may well be aesthetically unpleasant for a disproportionate number of people, with the degree of enhancement positively but in a hard to quantify way, correlated with the cost of the modifications to the environment needed to achieve any such possible enhancement.
3.) The first two considerations are mostly ignored by LG in their attempts to paint an overly rosy and overly optimistic picture for their bifacial panel.

As usual, take what you want. Scrap the rest.

[ncs55]

Blah, Blah, you are just picking anything negative that you can. I will scrap that whole post. Thank you.

[adoublee]

This has the potential to be a great panel for the toolbox of those who design PV systems. DIY's or marketing sensitive public with sloped residential roofs be warned I suppose.

For the rest who are interested in the fact that bifacials can provide aesthetic benefits (semi-translucent for some illumination, more interesting backside that camouflages leads more than a white backsheet) or can see enhanced production when properly installed on a flat white commercial roof or any ground mount or canopy where it snows, it is great to see a product from high volume manufacturer's like LG. If the price premium is as minimal as seen overseas (beyond the inherent LG price premium), these things will probably be in line to be used in many ground mount arrays in regions with moderate to heavy snow cover.

And I have seen energy boost of the old Sanyo bifacials in the range of 20% on a low-slope white roof. There were added racking costs associated with installing ballasted at 30 degrees for what it is worth. If these install in the same way any panel would on a ground mount - no added cost. And if one was already pricing semi-translucent options like those out or coming out from other manufacturer's, this has potential to be a cost saving. But not for a residential, DIY customer, with no professional advice, and a sloped roof, who has scoured LG's UK website, or Australian RE forums, and been fooled by their panel spec sheet, that does not include the backside contribution in the panel wattage rating.

[jflorey2]

The blurb says "up to 25% more energy....under optimized surrounding conditions". What B.S. ! Who, or how many folks have such conditions, or want to put up with the aesthetics such optimistic #'s would require ? For that matter, how many people understand what any of that means or entails ?

There's an 80kW array down here that uses bifacial panels. It's a sun deck over white concrete at a restaurant. The transparent backsheet allows a decent amount of light through.

More and more often down here in San Diego I am seeing freestanding structures (parking lot arrays, carports, sunshades, lampposts) that could benefit from such panels, both from the light they allow through and from the additional power from the reflected light.

[Willaby]

There's an 80kW array down here that uses bifacial panels. It's a sun deck over white concrete at a restaurant. The transparent backsheet allows a decent amount of light through.

More and more often down here in San Diego I am seeing freestanding structures (parking lot arrays, carports, sunshades, lampposts) that could benefit from such panels, both from the light they allow through and from the additional power from the reflected light.

Definitely. Not only that, but as TOU periods shift to 4pm West facing tilt mounted panels would have a better angle of incidence (is that right?) off a flat white roof. The frontsheet would be most productive for peak period credits with the backsheet adding productivity mid-day. Even additional spacing wouldn't be necessary for this arrangement.