25 Feb 2009
To possibly get an idea of what you are missing-out on, here are my statistics from N. Bulgaria where it works very well from May till September - inclusive.
Approximately 40 m of C40mm diameter hose, coiled-up like a record-groove and laid on two strong pieces of "scrap" of plywood which is resting on bricks to keep it off of the damp ground. 2 sheets of (rather expensive) 3mm plastic laid over it all. One end of hose goes up to tap, the other up to rim of receiver-vessel. Modus operandi: Fill pipe - leave for an hour or two.
Every hot day (= most days here) I had more scalding-hot water than I could use. I could not have considered making this much hot water by burning gas. As it was the little bottle lay un-molested for a record 4 months ? just doing teas + cooking.
This year I am making a decent installation of about the same area, but it is a commercial panel which has 8 ? parallel tubes of about 8mm dia going between 22? mm manifold-pipes (In/out) and the tubes are thermally connected - soldered ?) to what looks like copper foil. The whole lot is black, and then has a glass cover and is in an alloy surround. This unit will share a primary heating-coil in the header-tank, with the "petchka" - which burns anything. Filling this primary circuit must be done thoroughly, to make sure no air remains because that will break the convection circulation. It also needs a filler-pipe-cum-vent to enable top-up and avoid pressure build-up. Cost off panel about 150 - 160 Euro.
I hope to let you know how it goes.
25 Feb 2009
Wailing Sirens please !
Did someone seriously suggest that electrical energy from "solar pv" is some kind of way of makinghot water instead of putting water-filled panels in the sunshine ? - or am I getting too old ?
Please please please !! try to realise that electrical energy is worth about 15 ? times as much as "heatenergy", and that electrical appliances do not run on hot water !! whereas hot-water appliances
- whilst they do "run on electricity" (because anything will do) - run direct on Sunshine at "1/15?" of the cost, leaving you with your priceless electrical things all useable.
Energy changes-hands like a One way street - to Heat. No return.
26 Feb 2009
Powertree. I'm not totally sure what you are saying here? But perhaps I didn't make myself clear enough. I'm not suggesting that PV is better than thermal, but for some it may be..
Firstly, let's assume that not many people want coiled hose, placed on "scrap" plywood, but want aesthetically pleasing tubes/panels fitted nicely on their roof.
Secondly, let's take this scenario, which is not untypical:
We have a 4 bed detached property, gas heated, with a 200ltr cylinder, south facing roof etc.... The property has a main bathroom, and an en suite with an electric shower, which is used in preference to the main bathroom. There is a cold fill washing machine and dishwasher. The children have "flown the nest", and mum and dad are both retired. Where is the hot water usage??
We have 2 choices. Size a system based upon occupancy, or on property size. If we size it upon occupancy, then when the property is for sale, the solar is not going to be such a big selling point to the family of four, at least two of which will, probably, use the main bathroom, using the stored hot water. If we size it on property size, then the system is extremely inefficient for the current occupants, since during the summer time, it will probably not do much as the stored water temperature wouldn't have changed much, as they haven't used much? Therefore, your thermal system will "turn on" for a very short time.
Either way, for the current occupants, it doesn't look like a particularly atractive proposition, financially. A rough calculation could put an installation cost of around £4k, with savings of around £100, if using Goodenergy, who are now paying 4.5p/KWh generated for solar thermal.
Compare that to just a 1KWp PV system, producing let's say 800KWh/annum. As the current occupants are retired, they spend more time at home during the day, thus using more electricity, than those who work. Therefore, utilising the electricity they are generating (especially if they put the dishwasher/washing machine on during the day!). Goodenergy are currently paying 10p/KWh generated, regardless if they are used or not (but take your ROC's), so that's £80. Then there is the saving on top of that. Goodenergy are currently charging 14p/KWh, so if you use 70% of your production? Then that's further £78. Total= £158. Installation cost of around £6.5k, but take off £2k grant, and you're paying almost the same.
If energy prices rise in unison, then the financial saving on PV becomes progressiively greater. PV, typically, has a longer lifespan, less maintenance (if "anti freeze" is used in the solar thermal, which will need changing every 4/5 years?). Without pre-empting any possibility of "feed in tariffs". I still know what I would choose, if I were in this situation?
27 Feb 2009
Solar thermal heat and hot water can be greatly reduce the consumption of natural gas. Here in California, 85 percent of all natural gas in residences is used for heat and domestic hot water. We are seeing huge demands for solar thermal integration of radiant hydronic heat, domestic hot water and in some cases radiant cooling. Depending on the size of the house, you can get by with an existing hot water heater.
28 Feb 2009
I struggled through your hugely informative discourse on estste-agency and hypothetical occupants, Rocs, and benefit grants etc hoping to find some relevance to helping us move towards a "low carbon economy". I was unable to see any useful ideas in that respect.
You state that you "are not totally sure of what (I) was saying here..."
a) The only cure for that is to MAKE youself "sure", because it was oinly a few lines of simple English - not a hypothetical treatise.
b) Solar pv and Solar Thermal are in no way comparable since the two have completely different products. Electrical appliances (and transports) do not run on hot water !!
They have in common the energy source - The Sun. But of course, Solar Thermal negates the rquirement for the sad pensioners to have to waste their precious electrical (= negotiable inflation-proof currency) Energy in providing the few cups of hot water that they need each day
(b) is a re-statement of the "wailing sirens" alert, to which you replied (I guess)
It seems that someone needs to point-out that subsidizing wastefull systems - when waste-free systems cost no more (and likely far less ) can never help any kind of economy - low whatever it might call itself. This is simple arithametic, not someone's opinion.
Money from "ROCs" etc. for trying to be environmentally friendly ? simply undoes any "carbon benefit" which the recipients may have actually provided, since they then spend it - likely as not -directly or otherwise - on gas and oil.
Finally, I must point-out that if a lot of old rubbish lying in the garden - in the Sun - can provide prolific hot water (as it does), this demonstrates to those of us not terminally mentally crippled that getting hot water from Sunshine is not an expensive business - certainly at this Latitude.
Did you read the message which prompted me to write the Alert ! ?
I doubt that it would have made any odds to your efforts which all completely missed the point, which is to avoid the burning of fuels.
Burning of fuels is equivalent to the use of electrical energy to provide "Thermal energy" -
because about 1/10 as much fuel could be used to heat the thing directly, and no expensive investment is rrequired. Hence "CHP" of which you may have heard
Evidently, non of this is of any relevance to "Estste-agents" who will allways - they feel - be able to buy the House on the Hill - or - if push comes to shove - a Cruise liner ?.
02 Mar 2009
Powertree. I point to your comment about me missing the point, that the whole idea is to stop the burning of fuels. If I can point you back to the the purpose of this blog, which was made in the first paragraph, which is primarily centred around the financial viability of solar thermal, not just about "helping us move towards a low carbon economy". Unfortunately, many people want to do"their bit", but also want to know about the finances.
The blog was purely meant to provide people with another perspective, so they don't get sucked into paying money for something that , ultimately, not provide the benefits that some lay claim to, and give them another option that , for similar money, save them more in the long run.
The comparison made was purely from a financial viewpoint, not as a comparison between, as you say "two completely different products". However, what I may point out in response to your comment "Did someone seriously suggest that electrical energy from "solar pv" is some kind of way of makinghot water instead of putting water-filled panels in the sunshine ? - or am I getting too old ?". Some people do indeed have their hot water heated by electricity!
Whilst I agree, that "a lot of old rubbish lying in the garden-in the Sun-can provide prolific hot water.." not many people want that, I would imagine that's why someone came up with the idea of nice, neat tubes/panels??
02 Mar 2009
Right enough. Let's say that the object of the exercise is to survive as well as we possibly can - whilst Minimizing the use of fossil fuels.
To do this we cannot afford to waste. And to make hot-water from your precious Solar pv - unless no other option is available, is very counter-productive as you must realise.
i.e. if you have sunshine then - as I have tried to say, however badly - hot water panels make hot water at a very small fraction of the cost, because the heating-effect per sqare metre of roof/garden is about 6 times, and the cost of the installation, I have no exact ratio-figure for, because it is obviously another small fraction of the cost of an equal area of "pv". I hope you see what I am "driving-at" because "solar pv hotwater" is probably not sustainable, and even if it were, it is silly to impoverish oneself needlessly.
Yes, I realise that many folks use electic is used to make hot-water. I even make cups of tea by electric in preference to my bottled gas. However ! - when the happy day arrives that I my bio-composter-gas plant is a reality - Gaz it will be !
You point to various subsidies available, but if these are spent on un-sustainable systems we are not doing as well as we otherwise could, either for ourselves, or the climate thing. It is "needless impoverishment" !
To digress to "Wind-energy" - as a large example of this - if you can bear with me. This is my Phd-in-a-wood subject .
Current (80 m high) "technology" is actually not commercially viable, and HENCE, not environmentally beneficial. During its entire life, it makes only a fraction of the energy required to replace it. It survives as a parasite on the rest of the generating industry, by means of ROCs -
and even LOCs, I'm told. but I'm just not interested.
Meanwhile - and this maybe why I am so "bitter" (but not twisted), I have demonstrated that 5% p.a. of cost is readily obtainable from a sensible system, and this time no-one else is interested !.
(DtI, Min of Env. BWEA AWEA "Conservation groups" ... you name it )
It makes me wonder what the point of school, Arithametic, etc. actually is.
The Show, apparerntly, must go on ?
Thank you. email@example.com
01 May 2009
A more efficient and cost effective renewable energy system is needed. R3
A more efficient and cost effective renewable energy system is needed.
To accelerate the implementation of renewable electric generation with added incentives and a FASTER PAYBACK - ROI. (A method of storing energy, would accelerate the use of renewable energy) A greater tax credit, accelerated depreciation, funding scientific research and pay as you save utility billing. (Reduce and or eliminates the tax on implementing energy efficiency, eliminate increase in Real estate Taxes for energy efficiency improvement). Tax incentive and rebates have to be tripled.
In California, you also have the impediment, that when there are an interruption of power supply by the Utility you the consumer cannot use your renewable energy system to provide power.
In today's technology there is automatic switching equipment that would disconnect the consumer from the grid, which would permit renewable generation for the consumer even during power interruption. Energy storage technology must advance substantially. “Energy conservation through energy storage”.
New competition for the world's limited oil and natural gas supplies is increasing global demand like never before. Reserves are dwindling. These and other factors are forcing energy prices to skyrocket here at home. It's affecting not just the fuel for our cars and homes, it is affecting food prices and it's driving up electricity costs, too. A new world is emerging. The energy decisions our nation makes today will have huge implications into the next century. We must expedite the implementation of renewable energy.
A synchronous system with batteries allows the blending of a PV with grid power, but also offers the advantage of “islanding” in case of a power failure. A synchronous system automatically disconnects the utility power from the house and operates like an off-grid home during power failures. This system, however, is more costly and loses some of the efficiency advantages of a battery-less system.
We’re surrounded by energy — sun, wind, water. The problem is harnessing it in an economical way.
Jay Draiman, Northridge, CA