#1 July 27, 2014 10:23:00

rogerhoward
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Hot Water Temperatures


Today I have started keeping some daily records of water temperatures at the top and bottom of my Hot Water Cylinder (which here is fed by just solar thermals via a traditional unvented water system).


The aim overall is to try to quantify nightime temperature loss and daytime temperature gain and, if possible, establish the times of day when gains switch to losses and vice-versa. I imagine that this has a seasonal pattern to it. But with the solar collectors being on the West roof here, it's the daily pattern that I'm really interested in.


If I can do this correctly, it is is possible that the results may be of interest at some point to some Microgeners who have implemented solar PV switching to power their hot water immersion heaters, for comparison. Comparable records would need to have been kept or calculated for comparison, of course. Hence why I'm mentioning it now, as I'm not sure at this stage how long I shall, in practice, continue with this record-keeping.


For the winter months I shall be switching on the gas boiler, and such temperature record keeping would no longer be of so much interest to me anyway. We are still solar-only during most of the autumn months though, although obviously as the year progresses the water takes progressively longer to reheat following some daytime household use of it. (I am intending to take my temperature readings prior to some household use or other of it though.)


N.B. The Good Lady here blames the Solar Farm for turning me all nerdy like this!










Economy 10 tariff provides 6.9p/kWh off-peak import between 12am-5am, 1pm-4pm and 8pm-10pm; http://www.pvoutput.org/aggregate.jsp?id=21047&sid=18934&v=2&t=m on approx. 63% off-peak usage, 22% solar usage, and 15% peak-rate usage.
1,900kWh annually is exported, mostly in summer, on approx. 3,200kWh generation. Approx. 4,500kWh/year is imported, mostly for (a) winter and springtime off-peak Storage Heaters, and (b) off-peak hot water Immersion heating (which is “dumb”, i.e. not linked to the solar PV).
PV array is split East-West. Income is from Phase II 21p/kWh Feed-in-Tariff plus smart metered 3.2p/kWh Export Tariff.

Edited rogerhoward (July 27, 2014 10:23:00)

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#2 July 29, 2014 08:32:00

Capetown
From: The Banks Of The River Mole
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Hot Water Temperatures


DHW Tank Performance. I do find it quite an interesting subject, as I'm able to heat the water in any one of 4 ways! What goes on inside the tank has always been a bit of a mystery to me, when I had a woodburning boiler stove installed I fitted a temp gauge near the top of the tank.  The solar thermal sensor at the bottom of the tank allows me to see roughly what is happening at various stages of the heat cycle. A few of the things I've learned are, any heating coil will only heat the water above it.  Hot water is drawn off the top and fresh cold water is introduced at the bottom of the tank.  My tank does not encourage stratification.  My  Solar Thermal Array faces west so maximum heating occurs in the afternoon and evening in the summer and only drops a few degrees overnight. 







The gene pool has no lifeguard!

Edited Capetown (July 29, 2014 08:32:00)

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#3 Aug. 5, 2014 20:30:00

rogerhoward
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Hot Water Temperatures


Hmm, I'd just assumed that my cylinder drawing-off water from the bottom was normal for our type of non-stratifying water cylinders (yes, other than during the overnight temperature losses, mine's like that too).


Before mentioning any demand-side figures, does anyone find unusual my overnight bottom of cylinder losses of between 11.9 to 16.8 (or top of cylinder losses of between 7.9 to 13.9) ?










Economy 10 tariff provides 6.9p/kWh off-peak import between 12am-5am, 1pm-4pm and 8pm-10pm; http://www.pvoutput.org/aggregate.jsp?id=21047&sid=18934&v=2&t=m on approx. 63% off-peak usage, 22% solar usage, and 15% peak-rate usage.
1,900kWh annually is exported, mostly in summer, on approx. 3,200kWh generation. Approx. 4,500kWh/year is imported, mostly for (a) winter and springtime off-peak Storage Heaters, and (b) off-peak hot water Immersion heating (which is “dumb”, i.e. not linked to the solar PV).
PV array is split East-West. Income is from Phase II 21p/kWh Feed-in-Tariff plus smart metered 3.2p/kWh Export Tariff.

Edited rogerhoward (Aug. 5, 2014 20:30:00)

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#4 Aug. 11, 2014 05:57:00

Capetown
From: The Banks Of The River Mole
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Hot Water Temperatures


I did some comparison measurements last night and this morning. The temp at 3/4 height of the tank lost 3C in 6 hours, giving a loss of 0.5C/hour. The reading of the sensor at the bottom of the tank didn't change in 6 hours. I'll repeat the  measurements over a few nights.







The gene pool has no lifeguard!

Edited Capetown (Aug. 11, 2014 05:57:00)

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#5 Aug. 17, 2014 11:03:00

rogerhoward
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Hot Water Temperatures


Crikey, a big difference to mine, then. Thanks for that Capetown.


I'm now, on Saturday, having my creaky vintage-age mechanical controls replaced along with a replacement to my faulty cylinder thermostat. I might be also able to replace my 10-year-old water temperatures monitor with this new one that has a capability for data downloading to computer.


So I'm meantime holding off until after next weekend any resumed water temperature monitoring.










Economy 10 tariff provides 6.9p/kWh off-peak import between 12am-5am, 1pm-4pm and 8pm-10pm; http://www.pvoutput.org/aggregate.jsp?id=21047&sid=18934&v=2&t=m on approx. 63% off-peak usage, 22% solar usage, and 15% peak-rate usage.
1,900kWh annually is exported, mostly in summer, on approx. 3,200kWh generation. Approx. 4,500kWh/year is imported, mostly for (a) winter and springtime off-peak Storage Heaters, and (b) off-peak hot water Immersion heating (which is “dumb”, i.e. not linked to the solar PV).
PV array is split East-West. Income is from Phase II 21p/kWh Feed-in-Tariff plus smart metered 3.2p/kWh Export Tariff.

Edited rogerhoward (Aug. 17, 2014 11:03:00)

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#6 July 31, 2015 21:53:30

Groundhogdog
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Hot Water Temperatures

At the end of January 2015 I fitted a:
SolarImmersion Power Diverter to use surplus power from the PV panels to heat Domestic Hot Water (DHW)
also a CHOPCLOC which stops the Gas Boiler firing up for between 15 and 45 minutes per hour - I will not be able to comment on how much Gas it saves but CHOPCLOC say a minimum of 11%
also Wattson to check when I am using electricity, how much the panels are producing and how much is from the grid.

I keep daily records of my Gas and Electric usage from the grid and how much electricity my panels are producing. All this information is entered on a spreadsheet at the end of each month. These records started in January 2014 so I am now comparing 2014 and 2015 on a monthly basis.

My Gas Boiler hardly ever fired up in June (5 out of 30) and July (9 out of 31 days but 3 of these were me testing things out).

I think in the Summer months I am saving £10 on Gas but the real surprise was that I am saving £12 on electric because when the gas boiler is not heating the DHW the CH and DHW circulation pump is not working. Circulation pumps it appears are notoriously inefficient but Grundfos make the Alpha 2 15 50/60 Part number: 98734596 which is super efficient on electric and will also save money on Gas.

These are also worth a look at whether you have solar PV panels or not:
Ecocamel Shower Heads. I have fitted two Ecocamel Orbit Shower Heads, one to a power shower and the other to an electric shower. Saves on water and heating the water and both showers feel more powerful. Halves the water usage and the heating costs.
ScaleGuard an Electric Descaler that is fitted on the incoming main. Recommended by Thames Water and if the blurb is to be believed it changes the structure of calcium which means no limescale. Savings allegedly £150 per year.
Magnetic and sludge filter for your CH system which protects your boiler and reduces the Gas Usage by around 6%

Edited dave worley, billericay (31 July 2015 22.50)

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#7 Aug. 1, 2015 09:12:36

SolarDave
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Hot Water Temperatures

Hi Groundhogdog, some good savings from a range of methods. in terms of your heating, have you looked at using your PV solar to heat the house in the sring, summer and autumn time?
http://www.immersun.co.uk/
I have an Immersun2 which you can link to underfloor heating or a £20k argos heater. there's a link in another part of the forum on some of us with such an arrangement. some have their hot water tank connected, some with that and 1 or 2 air heaters.so I haven't had my heating on since I connected up to Immersun since April, so as you mention, not only am I saving on gas heating bills,but also the electric used by the boiler pump, which as you say is quite expensive. I know, because one winter I left the central heating on all day, but on a very low setting, and then the next year, put the central heating on twice a day. both my gas and my electric bills increased heavily with having the heating on very low allday - because the pump was busy all day, and it does use a fair amount of electricity when it kicks in. I must check out the ecocamel shower heads, as we have electric showers and are on a water meter too. Thanks for spreading the word.

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#8 Aug. 1, 2015 20:17:06

Groundhogdog
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Hot Water Temperatures

Hi SolarDave

Yes, I have asked Dyson who make the blade less fans if they have considered trying to sell to people with Solar Panels as they could be used as a cool fan in the summer and a heater at other times. Their fans in cool air mode use very little electric. I wanted to know if in the winter their fan would be able to push out heat across a power gradient if there was surplus electric available from the panels. No reply from Dyson so far so I need to chase them up.

I also think there is an opportunity for cylinder maker and immersion heater maker to get together an create something especially for solar panels where the immersion heater element is extra length (mines 27" at the moment so I am very proud of it) to get near the bottom of the tank and has a stirrer built into it to help circulate the heated water within the tank. Often it ends up sat near the top. I know it is easier for manufacturers to make a cylinder (circular tank) but if the tank was a square shaped or preferably rectangular there is an opportunity to get more water into the same space or alternatively the same amount of water in a smaller space. The tank would still need to have entry and exit pipework for the Gas Boiler /circulating pump to heat the tank in winter.

With regard to the Ecocamel Orbit Shower it is very light and feels cheap but it really does work very well so far.

I have tried to attach the spreadsheet file that I use to record my monthly and annual Electric, Gas and Water usage and my PV panel production but I am not sure if it works so perhaps you can let me know.

Many thanks.

Groundhogdog

Attachments:
attachment ELECTRIC GAS WATER USAGE AND PANEL PRODUCTION.xls (121.5 KB)

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#9 Aug. 2, 2015 09:52:53

SolarDave
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Hot Water Temperatures

Hi Groundhogdog, Thank you for letting us have sight of your evidence base within your s/sheet. I will look at your spreadsheet this coming week, but I think you are well on the way. This sort of detail would be useful for Microgen in terms of an evidence base for supporting their research on pv solar and domestic use. from 1st glance, it is comprehensive and far better than my spreadsheet, as generally forget to take readings! what I do know is that both my electric and gas bills have gone down significantly over the same time period, as once you are on the PV solar trial, u start investigating other areas which you find are giving rise to higher bills, eg using led lights rather than the older bulb-type, turning the microwave off stand-by, going from a cathode ray TV to an LED tv, invest-to-save purchases eg the Immersun2.

so at this point, after all our energy saving measures, I am on an electric monthly bill of £16/month and gas of £28/month from using Br Gas.

i'm sure I can reduce these further, and the Immersun2 will reduce these a bit more, as I have noticed a reduction since its installation mid-April 15. it will probably reduce the gas as it will allow us to leave turning on the central heating until Nov and turn off end of Feb next yr. not a great deal, but a gas consumption from £28 to 24 per month hopefully. we have a 1940's semi and there are 4 of us, to give u an idea of space and number of ‘energy users.

On the Grundfos, it looks like £260, so I will need to check what the ROI is on this. if and when we replace our boiler pump, you’ve pointed me in the direction of the UrP directive, so thank you for pointing out the lower energy pump installation, as I will check out what low energy pumps are around, when the time comes. If I was to replace, the the cost will be down to what the ROI is on a higher cost lower energy pump is compared to a lower cost, but higher energy usage pump would be.
for I found a link to another competitor I assume, who stated
“With all this information, it is clear to see that ErP is the correct terminology. For any company to say that they are EuP compliant is a mute point as that directive is outdated; ErP compliancy is all the matters.” the EuP acme out in 2005 and the updated version, ErP came out out in 2009. whether there is any material difference for eg a heating pump, I couldn't find out, but may be you know if the 2 parts are the same or different?

Edited SolarDave (Aug. 2, 2015 09:55:08)

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#10 Aug. 2, 2015 13:27:22

Groundhogdog
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Hot Water Temperatures

Hi Solar Dave

This is the information I think you want I to understand why Grundfos want to use ‘EuP ready’ rather than ErP:

https://uk.grundfos.com/about-us/news-and-press/news/the-eup-erp-directive-and-the-use-of-the-term-eup-ready.html

I can neither agree with or disagree with Grundfos but for the benefit of people like me it would be great if there was a definitive answer.

Energy efficiency index (EEI) also needs to be looked at:

So here is a link to another pump manufacturer ‘Wilo’ both Wilo and Grundfos quote EEI.

http://www.wilo.co.uk/home/products-expertise/heating-air-conditioning-cooling/underfloor-heating/#.Vb4TgPlVhHw

One of my concerns is about pollution from Gas Condensing Boilers, they are very efficient compared to non condensing boilers but they send a plume of acidic vapour (pH 3.5 to 5) into the air, I hear 1.7 tonnes per year from each and every one, and there are millions of them. This vapour cannot be good as it will eat into concrete. It creates a green slime from the gutter down pipe as my neighbours plume blows straight across my new roof, when the prevailing Westerly wind is blowing the plume goes back across their roof and is gradually over five years turning their roof tiles into sand, if it destroys concrete it cannot be good for our lungs! By using the SolarImmersion diverter at least during the summer months I am not polluting the air outside my house.

With regards to the Grundfos Pump mentioned previously, Ecocamel Shower Heads, Magnetic Filter and the Electronic Descaler I would fit all of these to cut my gas boiler usage and its resulting pollution regardless of whether I had solar PV or not. All reduce the gas usage but at some point there must be diminishing returns on savings.

I attach a picture of my house from the air which was taken after building work including the new roof two years ago.

Kind regards

Groundhogdog






Attachments:
attachment 280 MOUNTNESSING ROAD FROM THE AIR JUNE 2013.doc (790.0 KB)

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