Solar soluation and 1200 litre cylinder

yop

Guys,
Brother rang me today and said he had a guy calll to him today, first of he did not ask him enough questions, I have asked him to go back to him again.

But the summary is:
4 panels (he thinks flat panels)
1200 litre cylinder
labour etc

6000 euro.

Questions I ask is why does he need a 1200 litre cylinder, there are 5 in the house and from what I read they need about a 600 litre cylinder.

What do you think about the price? They also told him that the 4 panels will heat the house, they have a 2100 sq ft block constructed house, heated with rads, to be honest again this is VERY limited knowledge on my part, that they would not heat the house on this, but please correct me if I am wrong.

Thanks very much, I have done searches but I cant find any answers.

heinbloed

First of all an energy demand asessment is to be done.And then this asessment is used to calculate the outlay of the space heating system as well as of the DHW supply.This is how professionals work.Weather charts, architectural data as well manufacturer's data must be used to get a reliable result.From what you have told I take it that this company want's to use a large standard packet, one fits all.This not how professionals work.4 flatpanels (8m2)cost around €1,000-€1,500, a fully insulated tank of 1,200l can be got (at the high-end quality range, 3-coil, stainless steel) for about €2,000, a solarstation for around € 200.-, all net prices ex trader.Further an expansion barrel, some piping and insulation and fixings.So the price might be allright, if it includes VAT, a guarantee for a couple of years, maintenance for a couple of years.But the outlay seems overdimensioned if not used for home heating as well. And home heating with solar in combination with a standard radiator heating system won't give much satisfaction, the necessary temperatures won't be reached very often.4-6m2 flat panel collectors south facing and a 300l tank would be propably a better/more efficient way to go solar.And much cheaper. These packets (DHW only) can be got as standard solution from traders and installers for around €2.500.-, fully installed and guaranteed. I can't give any names of companies here on the forum, shop around.

yop

heinbloed wrote: »

First of all an energy demand asessment is to be done.And then this asessment is used to calculate the outlay of the space heating system as well as of the DHW supply.This is how professionals work.Weather charts, architectural data as well manufacturer's data must be used to get a reliable result.From what you have told I take it that this company want's to use a large standard packet, one fits all.This not how professionals work.4 flatpanels (8m2)cost around €1,000-€1,500, a fully insulated tank of 1,200l can be got (at the high-end quality range, 3-coil, stainless steel) for about €2,000, a solarstation for around € 200.-, all net prices ex trader.Further an expansion barrel, some piping and insulation and fixings.So the price might be allright, if it includes VAT, a guarantee for a couple of years, maintenance for a couple of years.But the outlay seems overdimensioned if not used for home heating as well. And home heating with solar in combination with a standard radiator heating system won't give much satisfaction, the necessary temperatures won't be reached very often.4-6m2 flat panel collectors south facing and a 300l tank would be propably a better/more efficient way to go solar.And much cheaper. These packets (DHW only) can be got as standard solution from traders and installers for around €2.500.-, fully installed and guaranteed. I can't give any names of companies here on the forum, shop around.

Cheers, thats spot on information. I will have get them to flesh out the quote more, so in summary what they need is about 50% of the cost of what they are been quoted, especially when using solar to heat a house is not an ideal solution as you wont get the required temp to run the rads.

Thanks

AckwelFoley

heinbloed wrote: »

First of all an energy demand asessment is to be done.And then this asessment is used to calculate the outlay of the space heating system as well as of the DHW supply.This is how professionals work.Weather charts, architectural data as well manufacturer's data must be used to get a reliable result.From what you have told I take it that this company want's to use a large standard packet, one fits all.This not how professionals work.4 flatpanels (8m2)cost around €1,000-€1,500, a fully insulated tank of 1,200l can be got (at the high-end quality range, 3-coil, stainless steel) for about €2,000, a solarstation for around € 200.-, all net prices ex trader.Further an expansion barrel, some piping and insulation and fixings.So the price might be allright, if it includes VAT, a guarantee for a couple of years, maintenance for a couple of years.But the outlay seems overdimensioned if not used for home heating as well. And home heating with solar in combination with a standard radiator heating system won't give much satisfaction, the necessary temperatures won't be reached very often.4-6m2 flat panel collectors south facing and a 300l tank would be propably a better/more efficient way to go solar.And much cheaper. These packets (DHW only) can be got as standard solution from traders and installers for around €2.500.-, fully installed and guaranteed. I can't give any names of companies here on the forum, shop around.

Excellent information

this is the case for all renewables.

Before you get a system, find out with an energy assement what energy the property requires first!

baldieman

Hi,
4 flat panels? DHW fine, but space heating, I wouldn't think it would be very effective. Although there's different views, I believe the evacuated tube is better for space heating as its more suitable for low angle sunlight. I would be inclined to start with 10sq/m about 5 panels. Another thing to remember is in the months of december and jan. the oil boiler will be running most of the time and in fine summer weather you might want a swimming pool to use up the hot water!! having said that there's still 4 - 5 months of good space heating potential.
I would assume the large tank is a buffer tank which is necessary. In order to use solar for space heating a long coil drawing heat from a tank of hot water is normal. The tank is possibly mild steel? but not necessarily a problem.

Independent

Hi we are in the process of building and seriously thinking about installing solar. I have a few questions, we think we will go with the tubes as they seem more efficient. Q1,Will the solar be of any benefit to our space heating (rads) or does it just provide hot water for showers etc. Q2 I am confused about sizing the system as we just have one child at the moment but hope to extend our family in the future, how many tubes should we install or do we add to the system as the family grows and what happens to a system when the kids fly the coop, what happens when you go on holidays, will it overheat? Q3 is it possible and whats involved if we got a PV solar panel to power the solar pump.
Thanks Ann.

heinbloed

Again: get your energy demand calculated.If you have no low temperature heating like UFH or wall heating then it makes no financial or enviromental sense to install a solar thermal heating system for providing heat to the space heating demand. It can be done technically but not economically or ecologically justified.If you're installing a large storage tank and have a large output from the collector then go ahead, install a wall heating system (there are ready made wal-heating panels available, dry building system) extra to the radioators and use the radiators as a back-up.The old ball park figure for domestic hot water demand is 50 liters per head. The newer rule of thumb is 30 liters per head.Half of the stored heat will be lost by storage losses within two days- if not used.So plan 100 liters of storage capacity per head living in the household and with the installation of evacuated tubes and a well insulated and installed storage tank you'll meet more then 60% of your anual DHW demand.Once you have 21mm insulated supply pipes installed (from and to the collector field) you can easily ad more collectors to an already existing collector field. The solar control station will be the same for a larger domestic installation as for a smaller one.And a second tank can be integrated with the old installation.Provided there is space somewhere.Always connect the washing machine and the dishwasher to the installation. Replacing electric heating energy with solar heating energy makes sense.There are two major systems to make the system "summerproof":first the standard method of installing an expansion vat where the steam can go without exploding the system. Secondly the drain-back system where the water from the collector goes into a storage tank once a certain temperature in the collector is reached (about 95 degrees Celsius). And being pumped back once the temperature in the collector drops below that pre-set limit.The drain-back system is the better one for several reasons: it's risk free since pressure isn't build up at first, it costs very little and it avoids the frequent renewal of the collector liquid (the water/glycol mixture).Ask your installers for details and try to get some literature on the issue. It is possible to use a PV panel to run the solar pump , I'm doing that with my own home installation. This saves money in several forms: the electricity bill will be lower ( costly day time tarifs will be introduced soon together with "intelligent metering"),it saves the temperature sensors and it it easy to install, no cables to the socket(no socket!), no fuse to be blown.And you can use the smallest pump available on the market as well. "EU21" has patented the system, "AMK" from Switzerland is selling it here in Ireland. There are also a few newer enterpreneurs in this particular field, but I haven't seen their installations yet and so can't comment about.But you can build your own as well, using available technology. The PV panel can be very small, I use a CIS PV panel from "Wuerth", about 20cmx70cm.Most pump manufacturers are selling now solar pumps as well, not the old heating pumps but smaller ones, A-rated, running on very little (solar)energy.Perfectly suited to the task. The company "Laing" has the longest experience with PV pumps as far as I know.But "Grundfoss" and "Wilo" have jumped onto the wagon as well, it makes sense. This controll method (using PV to run a solar thermal collector pump) is called " Global Radiation Control".Check the www for it.It's simple, it's beautiful. And cheap.

Independent

Hi all, just researching for solar evactuated tubes. Whats the best way to compare these? like with insulation you go for the one with a low conductivity, Thanks.

heinbloed

See what is available and then check it out with the aid of the estif home page. You'll find there not only the individual test results of the manufacturer's reports but also a calculater, an Excel sheet. This you can use to type in your data (see how much these differ at different outside temperatures due to bad insulation and other technical details!) and the Excell sheet will tell you if your chosen collector is better or worse then average.http://estif.org/(The site might be under construction, try again)The evacuated tubes have indeed a better thermal insulation factor compared to most flat panel collectors. But check this out on a case to case base.Not only the (solar radiation collecting) tube- the glass body- has to be looked at but the entire ensemble incl. the horizontal collector tube has to be seen. This is the weak point with tube collector's thermal conductivity, the vacum itself insulates very well but the rest of the insulation is usually kept slim for aesthetical reasons. And this isn't good for the wallet, the efficiency.

Independent

Thanks Heinbloed for your answer, but all that is over my head surely without going into all that technical jargon there is an efficiency output of each solar manufacturer.

rayh

Independent- You asked 3 questions and I will try be as basic as I can.
Q1. Will solar benefit rads – rads require above 60C – solar will not give these temps on many occasions over the year so not very helpful.
Q2. Sizing the system – you are buying a system which has a life expectancy of up to 30 years – how many persons in your house is probably the least relevant question – if you are only going to use to support your DHW – estimate your DHW requirement and assume a 60% to 70% energy saving.
Q3. Yes you can, but solve Q2 first.
In general you are looking at the next 30 years and today we tend to look at energy costs alone, but as we migrate from fossils fuels and deal with the challenges of climate change we need to consider these aspect against a new order of priorities