LVP Thermodynamic solar Panels

freddyuk

How much water per day do you need? If just a couple of showers and washing up it may be around 100 litres? If you put a simple immersion heater into a cylinder it should do that with in an hour from cold. That cost 1 unit per day. If you install a multi coil cylinder you can add solar thermal heating later if not now. This will provide most of your hot water and even in the worst weather will preheat your cylinder to around an average of 25-35c which means your immersion only has to raise the temperature 20-30c.(In summer it will be hot). It will cost nothing to run the solar once installed. It is simple to install and all the elements are easily replaceable if ever required. If the thermodynamic fails you have to replace the whole kit and caboodle.
You can have a top loading system in the summer where the solar heats the top part of the cylinder first and then reverts to the bottom as you should have a bigger cylinder to store the free energy. You can have the same idea with 2 immersion elements top and bottom and if you have off peak night rate this will count.
Compare the costs and see what you think.
Remember the Thermodynamic being monitored here are only supplying showers/baths and basins too. No washing machines or dishwashers. If you get yourself a hot fill washing machine you can use free stored solar water to do the washing and being a nice day it will recover quickly. The thermodynamic system will chug away whether the sun shines or not. I do not think the sun makes very much difference to recovery times but it is something we may discover eventually.

braka

freddyuk wrote: »

Compare the costs and see what you think.

Remember the Thermodynamic being monitored here are only supplying showers/baths and basins too. No washing machines or dishwashers.
If you get yourself a hot fill washing machine you can use free stored solar water to do the washing and being a nice day it will recover quickly. The thermodynamic system will chug away whether the sun shines or not.

I do not think the sun makes very much difference to recovery times but it is something we may discover eventually.

Sorry...
Just a couple of clarifications in case people who may be interested in the LVP Thermodynamic system get the wrong information......

1. ......"Remember the Thermodynamic being monitored here are only supplying showers/baths and basins too........

NOT TRUE....Our washing machine has both a hot and cold feed and it uses the hot water from the LVP tank (used a lot at weekends when students are home ..)

2. Quote.."...I do not think the sun makes very much difference to recovery times but it is something we may discover eventually".../Quote

The sun does make a difference....

Have a look at the attached spreadsheet with details of last 21 months data and last July / August in particular.


3. Our water is also heated to 55 deg C. ..... not 50-52 deg C as with some users.


4. "..... If the thermodynamic fails you have to replace the whole kit and caboodle..."

NOT TRUE ....

As I see it there are 4 main elements,
a roof panel,
2 heavily insulated pipes to/from this panel
an insulated tank (250 litres in our case)
and a compressor unit with control panel.

I understand compressor units for this are similar to a Fridge/freezer (I'm not an expert ..just going on previous posts)
...and our last fridge lasted over 30 years!

I suppose time will tell for both Solar and this system...

Lets try and stick with the facts and then everyone can weight them up for what their worth.

Wearb

braka wrote: »

NOT TRUE....Our washing machine has both a hot and cold feed and it uses the hot water from the LVP tank (used a lot at weekends when students are

I follow this thread because I am trying to compare thermodynamic panels with solar panels and can't work out which is best long therm.

Now to my point, my washing machine also has hot and cold fills, but from memory, the hot water is only used at very high wash temperatures, which in my case is very rarely done. Perhaps other machines can call on hot water for regular washing.
Just said I'd mention it as it may be relevant.

freddyuk

Thanks I am trying to get the facts! Now we have more information than before. I was under the impression your unit was all in one. Are you saying you can replace just the heat pump if it fails and not the cylinder? Can you check with supplier and get a cost for replacement notwithstanding any guarantee.
I apologise I forgot you had a washing machine also but the flow meter would help us gauge the amount of water being used. You seem to be using a lot from what you have said.
All good information.

John T Carroll

The Flowmeter is the key to all these "discussions" especially as the water will be heated to 55C (or whatever the setting is) at night so most of the draw off will be at this temperature during the following day. This, in conjunction with an energy monitor, would make the calculations for COP, comparison with conventionel Solar etc very easy indeed.

freddyuk

Calibrating the energy monitor would be worth doing. If you switch on the immersion I guess it should read 1200w if the heat pump unit is off.
Then if you covered the panel and measured the response input power you could check the effective input of the panel.
These are things I would like to do.

whitenoise

freddyuk wrote: »

. It will cost nothing to run the solar once installed. .

Correct me if I am wrong here, but won't the pump in the solar system cost money to run? also is there not maintenance needed every 4 years? - glycol water mix to be replaced? When we were looking into this we were told it would cost around €50 a year for the electricity to run the pump, and about €400 for the 4 year maintenance. So in essence it would actually cost €150 to run the solar system. Correct me if I am wrong here, I'm just going on what a couple of solar installers told me when I was researching what system to go for.

freddyuk

The pump on low speed is less than 25 watts. It only runs when the temperature differential is sufficient and then it pumps for a couple of minutes to transfer the heat into the cylinder. It then shuts off. It does this all the time there is sufficient heat to transfer from the collector. An A rated pump could use even less.
So on this basis even if the pump was running 12 hours a day (which it won't) it will burn 109kWh per year or €20. I estimate it will run for less than half of that time.
If you use decent Glycol mix not the cheap stuff you do not need to change it and even if the system stagnates it can withstand this abuse too.
Obviously periodic maintenance is good practice to keep it in tip top condition but the cost is negligible. Having a simple bypass system prevent the system stagnating thus saving even cheap Glycol.
The other electricity is consumed by the controller and diverter valve which is not measurable.
So you can see €400 is a complete rip off. Just changing the fluid is not going to cost that much especially if the system was correctly installed in the first place.

whitenoise

freddyuk wrote: »

The pump on low speed is less than 25 watts. It only runs when the temperature differential is sufficient and then it pumps for a couple of minutes to transfer the heat into the cylinder. It then shuts off. It does this all the time there is sufficient heat to transfer from the collector. An A rated pump could use even less.
So on this basis even if the pump was running 12 hours a day (which it won't) it will burn 109kWh per year or €20. I estimate it will run for less than half of that time.
If you use decent Glycol mix not the cheap stuff you do not need to change it and even if the system stagnates it can withstand this abuse too.
Obviously periodic maintenance is good practice to keep it in tip top condition but the cost is negligible. Having a simple bypass system prevent the system stagnating thus saving even cheap Glycol.
The other electricity is consumed by the controller and diverter valve which is not measurable.
So you can see €400 is a complete rip off. Just changing the fluid is not going to cost that much especially if the system was correctly installed in the first place.

Yeah I had a funny feeling that it was very high alright

John T Carroll

My pump consumed a measured 43 Kwh last year on a fixed (lowest setting) speed, Two Flat Plate + 150 Litre Cylinder installation.

The devils

When I was getting my unit installed by the crowd I used I had a leak of gas and had to get recharged again, so I therefore was worried that the heat pump may off been damaged. Priced pump on danfoss website for less than 100 $.
Braka is right, all components of the system in question most of us have is replaceable.

freddyuk

John T Carroll wrote: »

My pump consumed a measured 43 Kwh last year on a fixed (lowest setting) speed, Two Flat Plate + 150 Litre Cylinder installation.

Only a little bit out.:)

The devils

Hi Guys,

Just a quick update on the excel sheet..

Hope your all keeping well, very quiet lately;);)

hiagain

I am looking at a 250l for €4,500 and have been told it will cost 55c a day to run i.e. €200 a year in electricity. I estimate our current electricity bill to be around €80 a month. If 30% of that is to heat water...€288 a year?? What am I missing?

The devils

Hi hi again...
Not sure what tariff your on, but I have change supplier some time ago..for instance this week I consumed 15 kW x 17 cent approx = 2.55 for the week..if it was like that all year round it would be 132.6 euro...but as you can see from my excel sheet it varies between winter and summer, therefore the average is approx 200 euro.
If you want any details on panel, and how I got mine installed contact me , I installed mine myself and it was cheaper , a lot cheaper..
Good luck

hiagain

The devils wrote: »

Hi hi again...
Not sure what tariff your on, but I have change supplier some time ago..for instance this week I consumed 15 kW x 17 cent approx = 2.55 for the week..if it was like that all year round it would be 132.6 euro...but as you can see from my excel sheet it varies between winter and summer, therefore the average is approx 200 euro.
If you want any details on panel, and how I got mine installed contact me , I installed mine myself and it was cheaper , a lot cheaper..
Good luck

That sounds fantastic The Devils. I feel like suppliers and installers work out what saving their product will give and then work out how much to charge based on that, but I don't feel we are big users of hot water anyway and so it's not a real saving for us. To be sure though, I would like to do it for environmental reasons anyway.

Wearb

The devils wrote: »

Hi hi again...
Not sure what tariff your on, but I have change supplier some time ago..for instance this week I consumed 15 kW x 17 cent approx = 2.55 for the week..if it was like that all year round it would be 132.6 euro...but as you can see from my excel sheet it varies between winter and summer, therefore the average is approx 200 euro.
If you want any details on panel, and how I got mine installed contact me , I installed mine myself and it was cheaper , a lot cheaper..
Good luck

I am not being belligerent, just curious.
"15 kW x 17 cent approx = 2.55 for the week" Am I missing something by thinking that the same amount of heat could be gotten from kerosene for about €1.50 ?

The devils

hiagain wrote: »

That sounds fantastic The Devils. I feel like suppliers and installers work out what saving their product will give and then work out how much to charge based on that, but I don't feel we are big users of hot water anyway and so it's not a real saving for us. To be sure though, I would like to do it for environmental reasons anyway.

Hi again, we where the same. 2 adults and 1 child. It's a great system, lately using it a little more 16 showers and 3 baths approx per week. Also cleaning bottles and baby stuff..use dishwasher a little less.

During installation I decided to separate the system from the gas and leave the thermo unit working on its own..
Honestly if you need anything on it let me know, hate to see people getting ripped off..

Good luck

The devils

Wearb wrote: »

I am not being belligerent, just curious.
"15 kW x 17 cent approx = 2.55 for the week" Am I missing something by thinking that the same amount of heat could be gotten from kerosene for about €1.50 ?

Wearb I have no idea..if kerosene for 1.50 get heat 1400 litres approx of hot water..well great. I had a gas and electricity heater option beforehand..now just gas central heating and the thermo unit..
Good luck and thanks

Wearb

The devils wrote: »

Wearb I have no idea..if kerosene for 1.50 get heat 1400 litres approx of hot water..well great. I had a gas and electricity heater option beforehand..now just gas central heating and the thermo unit..
Good luck and thanks

OK thanks. I am just trying to figure out the payback time or even it would ever payback for installation and running costs.
btw there is almost 10Kw of energy in a litre of Kerosene. After taking losses into account I came up with a rough cost of €1.50 for 15 Kw. Just wasn't sure how well my figures would stand up to scrutiny.

freddyuk

Well to put it in perspective for the same money you can run your immersion heater for one hour each day of the year and it will cost you €4,500 less! If you wanted to run your immersion heater for 2 hours each day it would cost you €400 each year and again zero investment. You can probably work out the rest of the math yourself.
If you had a solar panel heating 250L it would likely cost next to nothing (once installed) for 2/3 of the year but you can still top it up with an hour a day immersion for €0.55 per day if required but the water is already guaranteed to be warm from solar thus it will not need much boost. You can reckon the solar will run for years at virtually no cost if looked after. Your Thermodynamic will cost you every day and subject to inflation each year. Lifetime of a heat pump??? Who knows but they are not likely to be repairable.

hiagain

freddyuk wrote: »

Well to put it in perspective for the same money you can run your immersion heater for one hour each day of the year and it will cost you €4,500 less! If you wanted to run your immersion heater for 2 hours each day it would cost you €400 each year and again zero investment. You can probably work out the rest of the math yourself.
If you had a solar panel heating 250L it would likely cost next to nothing (once installed) for 2/3 of the year but you can still top it up with an hour a day immersion for €0.55 per day if required but the water is already guaranteed to be warm from solar thus it will not need much boost. You can reckon the solar will run for years at virtually no cost if looked after. Your Thermodynamic will cost you every day and subject to inflation each year. Lifetime of a heat pump??? Who knows but they are not likely to be repairable.

My first thoughts were to get a dual coil biomass/solar, as we are thinking of getting either a wood burning or pellet stove - my preference being for the former. I was thinking that in winter the stove would do the water and in summer the solar panel would. Any thoughts?

The sales guy for thermo (surprise surprise), suggested not getting the dual coil and using thermodynamic all year for the water, making the stove more efficient for the heating as it would not be heating water at all.

steve82

hiagain wrote: »

I am looking at a 250l for €4,500 and have been told it will cost 55c a day to run i.e. €200 a year in electricity. I estimate our current electricity bill to be around €80 a month. If 30% of that is to heat water...€288 a year?? What am I missing?

I think you have confirmed my assumptions too. The running costs are not dramatically dis-similar to an electric immersion

shane 007

hiagain wrote: »

I am looking at a 250l for €4,500 and have been told it will cost 55c a day to run i.e. €200 a year in electricity. I estimate our current electricity bill to be around €80 a month. If 30% of that is to heat water...€288 a year?? What am I missing?

What you are missing is your calculation accuracy. You are assuming your bill of €80 per month is made up of 30% heating hot water.
So either you are using extremely low volumes of hot water or the bulk of the €80 is for hot water.
1 hour of a 3kw immersion will give you exactly 51.6 litres of hot water from 10C to 60C.
1 hour of a 2.5kw immersion will give you exactly 43 litres of hot water from 10C to 60C.
I use approx 160 litres of hot water per day for a family of 4 so that would give me an annual electricity cost of €610.74 per year.
That would be 1131 hrs of a 3kw immersion per year & 1358 hrs of a 2.5kw immersion per year.
Basing cost of 18 cent per kwh incl vat & government levies, etc.

hiagain

There is no way that we would use more than an hour of hot water a day, partly because we have an electric shower though, and partly because we have gym membership, so even the shower doesn't get used that much

shane 007

hiagain wrote: »

There is no way that we would use more than an hour of hot water a day, partly because we have an electric shower though, and partly because we have gym membership, so even the shower doesn't get used that much

So how can you come on a thread to compare your usage costs with others when you do not use hot water from your cylinder???
That's like saying I have a very low gas bill compared to somebody else's high oil bill but I only am home once a month for an hour!!! Or I use naff all petrol in my car but I failed to mention I drive a diesel engined car....
Seems a bit pointless of a comparison.

hiagain

shane 007 wrote: »

So how can you come on a thread to compare your usage costs with others when you do not use hot water from your cylinder???
That's like saying I have a very low gas bill compared to somebody else's high oil bill but I only am home once a month for an hour!!! Or I use naff all petrol in my car but I failed to mention I drive a diesel engined car....
Seems a bit pointless of a comparison.

I hadn't really realised it until I said it Shane, to be honest. I didn't actually know how much others used. So I would only need 150L max, but I would probably get enough most of the time from solar. Your calculations have been very helpful

shane 007

hiagain wrote: »

I hadn't really realised it until I said it Shane, to be honest. I didn't actually know how much others used. So I would only need 150L max, but I would probably get enough most of the time from solar. Your calculations have been very helpful

TBH, if your usage is that low it would probably not be economically viable for you to install any saving measure as the payback would far surpass the lifespan of the installed measure. Not all systems are suitable for all households.

150L is in the realms of 3 days usage for you if you are only requiring in the region of 50 litres per day plus what you use in an electric shower. If you installed a measure, then you would have to upgrade your shower to be tank fed also, so you would need to factor in that cost too.

hiagain

Well the kids have baths and obviously I do the washing up. We are moving to a new house and I was thinking of power instead of electric and then using wood burning stove and solar power for the water and heating.

shane 007

Obviously then your usage will drastically increase & therefore your DHW heating cost will dramatically rise accordingly & a suitable measure would therefore prove it's worth.
For me, in Ireland solar has benefit but not all it's cracked up to be. High volume users are frequently topping up with secondary source & the general miserable summers we get has a large affect. Many people claim it gives you all you require from March to October but I would disagree. I would say if gives an average of 50-60% of your needs during these months, so frequent topping up required. The other 6 months is negligible gain.
Bare in mind, whilst a stove will be lighting in winter, it won't be in summer so you will still need to factor in additional oil/gas/immersion back up usage.