Regional Forums » USA • Canada • Africa • Europe • China • India • Indonesia • Pakistan • Central/South America • Australia/NZ | Algae | Alternative EnergyBiodiesel » FAQ • Production • Cold Weather • Advanced Methods • Business • BioHeat • Vehicles • Marine | Classifieds » Vehicles • Equipment • Jobs • Oil
Here is the link.
Can someone explain to me why PV/T systems arnt the norm?
flectere si nequeo superos, Achaeronta movebo! -Virgil
As long as Im on a roll...
why isnt this low tech Organic rankine cycle technology on virtually any industrial system that has excess heat? Eventho there are offsets, you have the ability to produce e' and more importantly, offer a larger sink potential.
Froggy IMO the same reason PV systems are a niche luxury: COST. Today for a small PV system of 5 KW or less cost about $9 to $10 per watt installed. A 5 KW system generates assuming a 4 Sun Hour Day about 16 KWH of usable power or about $1.60 to $2.00 worth of electricity per day. Well if that system cost $45K to install, the payback time assuming not one penny spent on maintenance and replacement is 61 to 77 years. Now factor in that system will have to be fully replaced in that time frame and there is no payback, it is just a luxury.
Now for the system you pointed too, PV/T, would even be a higher cost per watt. Doesn't take an MBA to figure it is not cost effective, a high-school student could figure it out.
Dereck
dereckbc Froggy IMO the same reason PV systems are a niche luxury: COST.
Froggy IMO the same reason PV systems are a niche luxury: COST.
Fair enough but you are missing a big point and mine in particular.
People are infact putting up PV. It a billion $+ industry today. So obviously its not just cost... there must be another reason why co-gen discribed in this article isnt the norm.
Without a subsidy, no one would put it in.
Democracy is Two Wolves and a Lamb Voting on What to Have for Lunch. Liberty is a Well-Armed Lamb Contesting the Vote :: Benjamin Franklin 2003 F250 7.3 Powerstroke 2003 VW Beetle TDI
As the cost of generating electricity from non-sustainable sources rises daily, PVs will become more competitive.
Two '96 VW TDI B4 variants, '87 MB 300TD, '97 Ram 2500 Cummins, '89 Ford F250 diesel, Kubota lawn tractor, Diesel Generator... 31 Cylinders Kicking on the Sweet Sauce of the Soybean
soypwrd As the cost of generating electricity from non-sustainable sources rises daily, PVs will become more competitive.
They will never be able to compete with nukes.
The base solar thermal technology under the SolarDuct "delivers one of the fastest energy ROIs possible in the commercial and industrial sector". The Duct version just makes it easier to install on horizontal surfaces at the right angle to the sun. When PV is combined with the Solarwall technology, up to 6x the energy captured relative to the PV alone can be collected and used. The technology also cools the back side of the PV increasing its efficiency and life.
Centralised nuclear power plants cannot be compared to small distributed generation sources. Ontario is still paying for construction and debt on the last bunch of reactors built - up to 30% of your current bill! Look around, read a bit, like here.
Back to the original question, AECL, Ontario Hydo and the voters of this province are the main reasons solar thermal is not the norm here. But the real answer is that the "New World" is 50 years behind the old world. Solar thermal is mandatory, cost-effective and widely used across the planet.
If you want to look closely at the facts behind the Solarwall technologies, you will see that it is not cost that is the problem as dereckbc yelled at us. Nor is it even remotely intended to compete with 'nukes'. It reduces non-renewable energy use by replacing combustion with solar collection (without any conversion steps) and it saves industry money on heating costs with very short payback; money that could be used to keep people employed in this province.
cjheapsoypwrd As the cost of generating electricity from non-sustainable sources rises daily, PVs will become more competitive.They will never be able to compete with nukes.
Not True. PV have next to zero operational overhead compared to the operational overhead of a NPP.
In addition, PV's have a longer service life than the most common NPP designs currently in use.
Both things mean that PV EPG is potentially lower cost than NPPs.
What is needed for that to happen is simply higher efficiencies and enough mass production to drive down PV costs in the same manner all semi-conductors become cheaper when porduced in large enough quantities.
As for Solar thermal, IMHO that is a interterm solution until PV has matured enough. Thermodynamics says directly making e from solar energy is always going to have greater maximum efficiency compared to turning solar energy into heat or chemical energy and then into e'.
Voltaire Not True. PV have next to zero operational overhead compared to the operational overhead of a NPP. In addition, PV's have a longer service life than the most common NPP designs currently in use.
Voltaire that is far from the reality. I have about 10 years of deigning and maintaining solar PV systems. The systems installed from 8 to 10 years ago, roughly 50% of the PV panels have failed.
Don't throw warranties at me either because the manufactures play tricks on the consumers with miss-leading statements. We use BP and Kyocera the best in the biz and they both use similar warranty plans like 20-10-5 for an extra charge, or the standard 0-12-2. What the numbers mean is:
The first number is 80% output in the number of years.The second is the 90% output.The last one is the real number; Material & Workmanship.
The other very high failure items are the controllers and inverters. Most of the manufactures are consumer grade using inferior parts and designOne last point solar and wind will only be a small supplement because the wind does not always blow, clouds and night. Electricity is a spot demand product which requires generators on line 100% of the time. There is no way around that and Nuclear is the best bet for clean energy available 100% of the time.
froggy dereckbc Froggy IMO the same reason PV systems are a niche luxury: COST. Fair enough but you are missing a big point and mine in particular. People are infact putting up PV. It a billion $+ industry today. So obviously its not just cost... there must be another reason why co-gen discribed in this article isnt the norm.
The fact that *some* people are putting up PV panels does *not* mean it's "the norm". People who are putting up PV panels are not doing it because it makes economic sense (unless they can't do math, of course), but rather because they *want* to - and of course hefty tax credits make it a little more pallatable.
There are many options (such as the one you linked) for slightly improving the efficiency of electricity production from heat generation (such as reverse Peltier devices, aka Seebeck devices), but if the improvement in effiicency is not economically worthwhile, companies won't do it.
Mike see we know we can agree? You are smart enough to know it takes more than feeling good, it takes an economic push.
Now with that said: I will counter depending on what Solar Tech you choose, not only will it NOT pay for itself, but will produce more greenhouse gasses over the expected lifetime to make and operate it vs buying it from the grid. Reason: it take smore energy to make and operate than to buy it from the POCO.
Mike Briggs People who are putting up PV panels are not doing it because it makes economic sense .... but if the improvement in effiicency is not economically worthwhile, companies won't do it.
Maybe Im being Mr Obvious here but I think you answered my point. People that put up PV arnt doing it for economic reasons, what do they care about efficiency. They care about doing the right thing or PR or blowing money. All 3 reasons are also satisfied by co-gen heating, cost be damned. As you both observed, cost is being damned in virtually all cases anyhow so its obviously only a minor reason.
When you buy a Bentley, you are buying it to show off. Its not about efficiency or cost unless the customer wants to be green, then you will pay top $ for green (thus the market for Tesla cars).
When you buy a Civic, you do care about cost and efficiency.
Most of the companies are using the solar air heating for there company purpose. I now a company that uses solar heating as there energy processes for smart alternative source of liquid fuels and power generation well into the foreseeable future
superbiz The base solar thermal technology under the SolarDuct "delivers one of the fastest energy ROIs possible in the commercial and industrial sector". The Duct version just makes it easier to install on horizontal surfaces at the right angle to the sun. When PV is combined with the Solarwall technology, up to 6x the energy captured relative to the PV alone can be collected and used. The technology also cools the back side of the PV increasing its efficiency and life. Centralised nuclear power plants cannot be compared to small distributed generation sources. Ontario is still paying for construction and debt on the last bunch of reactors built - up to 30% of your current bill! Look around, read a bit, like here. Back to the original question, AECL, Ontario Hydo and the voters of this province are the main reasons solar thermal is not the norm here. But the real answer is that the "New World" is 50 years behind the old world. Solar thermal is mandatory, cost-effective and widely used across the planet. If you want to look closely at the facts behind the Solarwall technologies, you will see that it is not cost that is the problem as dereckbc yelled at us.
If you want to look closely at the facts behind the Solarwall technologies, you will see that it is not cost that is the problem as dereckbc yelled at us.
He didn't yell, he explained clearly why PV is not cost effective. Solar thermal is cost effective in many situations. That is not the case though for PV (solar electric).
Nor is it even remotely intended to compete with 'nukes'. It reduces non-renewable energy use by replacing combustion with solar collection (without any conversion steps) and it saves industry money on heating costs with very short payback; money that could be used to keep people employed in this province.
The system linked in the initial post is not pure solar thermal - it is a solar thermal-PV hybrid system. The reason it is not the norm is exactly what Derek said - cost. NOt cost of the solar thermal system, but cost of the PV system.
Voltaire cjheapsoypwrd As the cost of generating electricity from non-sustainable sources rises daily, PVs will become more competitive.They will never be able to compete with nukes. Not True. PV have next to zero operational overhead compared to the operational overhead of a NPP.
Nukes also have very low operational costs - the cost of nuclear power is predominantly the amoritized capital cost to build the powerplant (whereas coal power costs are attributable to a much greater degree to fuel and operation costs).
Huh? Virtually all nuclear power plants in operation in the US are at least about 30 years old or older. Some are >50 years old. PV service lifes are generally 30-40 years.
No, they don't.
The reason current silicon PVs are so expensive is not because of lack of mass production, but rather skyrocketing cost of raw silicon. Increased production capacity will just drive up the cost of silicon further, driving up the cost of PVs. What is needed is a shift to thin film CdTe and CIGS PVs printed on high volume low cost "inkjet" style printing systems. While that won't solve the "intermittency" problem of PV, it will at least bring the cost down substantially.
No way. I can explain why later - no time now. If you want to do some background reading though, see chapter 5 of my dissertation.
http://pubpages.unh.edu/~msbriggs/MikeBriggsDissertation.PDF
Solar thermal systems can easily achieve >95% efficiency. Solar electric will be hard-pressed to break 50%. Any photon energy above the bandgap energy is lost, excited electrons can de-excite back into a hole, etc.. - there are just too many losses for it to ever approach the efficiency of directly converting solar to thermal energy.
There is no viable, practical or cost effective reason to use combined PV Thermal systems like the Solar Duct.
I am very, very curious to know why anyone would combine a transpired solar air collector that operates at 70% efficiency at a very low, competitive cost/kw with another technology that provides at best 15% operating efficiency and a very high, uncompetitive cost/kw . Both technologies offer practical benefits when used on a building to provide heated air and electricity independently, however, to combine them does not make sense and I would like to understand where such an application would prove beneficial .
Transpired collectors in the US and Canada are typically installed vertically and are designed to work during the winter heating period where their vertical installation is seasonally optimized for solar gain in the winter while reducing the potential for overheating in the summer . This overheating potential is further reduced using a bypass damper to avoid heated air adding to the air conditioning load. PV modules on the other hand will generate most of their total potential power in nothern US states and Canada in the summer, wherein their best angle of installation is somewhat less than the sites' degree of latitude and facing true south. The combination of these two technologies, with their two conflicting optimal orientations and periods of power generation in a norrth American climate defeats the best uses of both technologies? Their combination offers no practical synergistic benefit, period.
Covering a transpired solar thermal collector with a flat plate PV module shades the transpired collector from direct solar radiation, allowing it to reap at best 50% (the heat emanating from the back of the PV module) of the 85% energy (the waste heat generated by the PV module) thus a maximum potential of 421 w/m2 vs. 1000 w/m2 under ideal conditions, excluding for discussion purposes, that the system is mounted vertically, not horizontally. Additionally, the increase in the PV module's output due to its cooler operating temperature (in the winter only, and only if their is considerable air flow behind the module to pull the heat away from the back of the module into the collector) by the mounting of a PV array on top of a transpired collector will most certainly be more than offset by the reduction in performance of the array in the much longer non-heating period resulting in an overall reduction in PV output on an annual basis. PV modules in general, reduce their output any time the module is heated which will always be the case during the non-heating months when installed on a SolarDuct. The loss is dramatically decreased even further in the summer when the heat emanating from the solar collector would raise the temperature of the PV array substantially over its rated 25C ambient temperature.
In time, the application of PV based coating or thim film applied directly to the transpired absorbver may make practical, sense however, applying a flat plate PV module on top of a transpired solar collector is nothing more than a gimmick.