Sign In »
Register Now!
Help
A night of contrast!!!!! Went out to get a gas reading last night and was really pleased that in 6 weeks we have only used £2-14 in gas for heating our hot water. Bearing in mind that there are 2 of us that shower and our boy has a bath. The water is only at 39 or 40 degrees when we shower, but that is shower temp anyway. So no need to add cold water to it. The only down side is that when we want to wash up the water isn't that hot, so occasionally we boil a kettle.
However, when I took the reading I noticed a smell of gas. This was at around 8-30 last night. Had the emergency gas people at the house for over 3 hours. After a lot of deliberation and a valve and meter change - problem sorted. It was only a small leak. My gas bill would have been even less! Turned out that when all the bits had been changed the gas man was scratching his head because his capillary device that contains liquid was still dropping when he shut off the gas. It was his plastic tube that was leaking - hence why we could still smell gas and it appeared that there was still a leak in the system.
Solar panels away!!!
#27
- Group: Frouks
- Posts: 3662
- Joined: 14-July 03
- LocationPoole, Dorset, UK
Posted --
Are you heating the water to over 65 degrees each day? This is to kill Legionella bacteria.
Paul.
#28 Guest_Chris Lloyd_*
Posted --
Quote
Paul Corfield - 3/8/2011 08:47
Are you heating the water to over 65 degrees each day? This is to kill Legionella bacteria.
Paul.
Uh, no. You are worrying me now. [wow]
#29 Guest_Chris Lloyd_*
Posted --
Though isn't Legionaires contracted through aspiration of water, like air conditioning units or whirlpool baths. Even in a shower it is unlikely that it would be breathed in?
#30
- Group: Frouks
- Posts: 3662
- Joined: 14-July 03
- LocationPoole, Dorset, UK
Posted --
The main way to get it is as you said, it gets into the lungs through breathing or choking, although I read it can also be contracted from just drinking water, but only in susceptible people. I supose the main thing is that the risk is there for it to multiply. I read it multiplies in temperatures from 20-45°c with 37 degrees being optimal. 55-65°c they will die in a few hours. Above 65 degrees it can't survive.
Some info from legionella.org in relation to water tanks.
What is the natural habitat of Legionella bacteria?
Legionella organisms are readily found in natural aquatic bodies and some species have been recovered from soil. The organisms can survive in a wide range of conditions, including temperatures of 0 to 63o C, pH of 5.0 to 8.5, and dissolved oxygen concentrations of 0.2 to 15 ppm in water. Temperature is a critical determinant for Legionella proliferation. Colonization of hot water tanks is more likely if tank temperatures are between 40 and 50°C (104 to 122° F). Legionella and other microorganisms become attached to surfaces in an aquatic environment forming a biofilm. Legionella has been shown to attach to and colonize various materials found in water systems including plastics, rubber, and wood.
Paul.
#31 Guest_Chris Lloyd_*
Posted --
I must admit your post has raised a bit of concern over this. The only thing I don't understand about this is that all hot water cylinders only have a head of water that is at the higher temperature end. The remaining part of the tank is anywhere between cold and that temp. Though I do understand in my case that the entire tank is at that temperature range where growth is particularly favourable. I wonder if intermittently heating the tank up hot would help.
I would be most concerned for my 2 year old boy - however, he only ever has baths. The cylinder is new as well, so hopefully nothing lurking that has built up over a long time.
I may have to check into this a bit further before making a decision here. There must be lots of people that preheat their water by this method, and many of those probably don't go on to heat the water up to 65 degrees if they can get away with the temp that the sun has given them.
I would have also thought that due to the health implications, the providers of all the solar panels would have some kind of duty to tell people to force the temperature on any given day to remove the risk?
Much to think about. As and when I get my second panel up it still won't be hot enough!!
I would be most concerned for my 2 year old boy - however, he only ever has baths. The cylinder is new as well, so hopefully nothing lurking that has built up over a long time.
I may have to check into this a bit further before making a decision here. There must be lots of people that preheat their water by this method, and many of those probably don't go on to heat the water up to 65 degrees if they can get away with the temp that the sun has given them.
I would have also thought that due to the health implications, the providers of all the solar panels would have some kind of duty to tell people to force the temperature on any given day to remove the risk?
Much to think about. As and when I get my second panel up it still won't be hot enough!!
#32 Guest_Chris Lloyd_*
Posted 07 March 2012 - 11:11
I got my second panel put up a few days ago. This one is different to the first and is made from a radiator that I have painted black. I have put it in series with the other flat panel one that has 25 metres of 10mm copper tubing braced to it.
Yesterday was the first sunny day we have had (bear in mind it is still very early in the season)
Water in the bottom of the cylinder was at 13 degrees yesterday morning. By midday the solar collectors had heated the tank up to 28 degrees. At best I was getting 2 degrees per hour.
This is very encouraging. I was getting 37 or 38 degrees in the whole tank in mid summer last year. To be getting this rate of rise so early is very good I think. I am hoping to get the water up to 45 degrees with the second one.
When I put the water on for a shower last night it took only 5 mins to heat the tank water in the head up to 48 degrees. If nothing else it is doing a good job right now at pre charging the water
Yesterday was the first sunny day we have had (bear in mind it is still very early in the season)
Water in the bottom of the cylinder was at 13 degrees yesterday morning. By midday the solar collectors had heated the tank up to 28 degrees. At best I was getting 2 degrees per hour.
This is very encouraging. I was getting 37 or 38 degrees in the whole tank in mid summer last year. To be getting this rate of rise so early is very good I think. I am hoping to get the water up to 45 degrees with the second one.
When I put the water on for a shower last night it took only 5 mins to heat the tank water in the head up to 48 degrees. If nothing else it is doing a good job right now at pre charging the water
#33
- Group: Forum Managers
- Posts: 3727
- Joined: 29-December 04
- LocationWest nor'west London
Posted 07 March 2012 - 12:58
Chris are you solar heating water that then goes on to heat mains water that comes out of your tap? If so then mains water should contain enough chlorine to kill off any bacterial growth and is never around too long to have substantial growths in it, as long as the two systems are seperate; that is there is a break in the system that feeds the solar panels, such as a header tank with a ball valve in it.
A Thermal store should heat up to about 60 °C for a viable system supplying hot water for baths and washing; its high enough to keep most growths at bay but may need premixing with a little cold before going to the taps. (To avoid a scalding risk).
A Thermal store should heat up to about 60 °C for a viable system supplying hot water for baths and washing; its high enough to keep most growths at bay but may need premixing with a little cold before going to the taps. (To avoid a scalding risk).
#34
- Group: Moderators
- Posts: 5159
- Joined: 18-July 06
- LocationGraham, NC USA
Posted 07 March 2012 - 13:38
scrapemedic, on 07 March 2012 - 12:58, said:
Chris are you solar heating water that then goes on to heat mains water that comes out of your tap? If so then mains water should contain enough chlorine to kill off any bacterial growth and is never around too long to have substantial growths in it, as long as the two systems are seperate; that is there is a break in the system that feeds the solar panels, such as a header tank with a ball valve in it.
A Thermal store should heat up to about 60 °C for a viable system supplying hot water for baths and washing; its high enough to keep most growths at bay but may need premixing with a little cold before going to the taps. (To avoid a scalding risk).
A Thermal store should heat up to about 60 °C for a viable system supplying hot water for baths and washing; its high enough to keep most growths at bay but may need premixing with a little cold before going to the taps. (To avoid a scalding risk).
Hey Liz,
You are correct of course, unless he is on a well pump. Though in that case we are talking about his routing the water through copper, (so other then the lead/tin solder the health worries are minimal).
Most cases of bacterial invasion of hvac systems are two fold. One, in the case of an open air heat exchanger-evaporator is the surfaces are not anti-microbial such as are gold, silver, tin and copper. Secondly, if the water in the system is in contact with wood, aluminum, galvanized steel, and subject to optical stimulation of algae growth it will be more likely to be hazardous or can become hazardous.
Chris΄s, designs are inline with standard solar system practices..., well except for the use of a car radiator which has a high level of solder binding the top and bottom tanks. As long as he wicked the solder away and ground the joints to bear copper and then used silver solder and a torch with acid flux to reattach the tanks he is fine. There were several articles about this in "Mother Earth News" and "Backpacker" over the years. The main points are, use anti-bological or inhibitor metals in your system, do not expose consumables to open air or in-direct light (UV in direct sunlight will act similar to chlorine, the problem is clouds...), finally insure your system does not contain hazardous materials or materials that are soluable, (IE: Nylon, acetate or polyester tubing/materials versus polyethylene).
#35 Guest_Chris Lloyd_*
Posted 07 March 2012 - 13:56
Liz, none of the water that is inside the panels ever comes into contact with the supply water. I have a second coil inside my hot water cylinder that is connected directly to the panels in a closed loop.
All heat is transferred through heat exchange only. The water is heated indirectly.
We used around 10 pounds in gas all of last summer heating water. The water would regularly heat up to bath temp of 38 or so. After what Paul said, on occasion I do let the cylinder heat up hot to remove any risks from legionella.
All heat is transferred through heat exchange only. The water is heated indirectly.
We used around 10 pounds in gas all of last summer heating water. The water would regularly heat up to bath temp of 38 or so. After what Paul said, on occasion I do let the cylinder heat up hot to remove any risks from legionella.
#36 Guest_Chris Lloyd_*
Posted 07 March 2012 - 14:03
LDC - No medium through which bad water can reach the supply water. I actually run push fit plastic pipe from the panels to the coil on the tank, which are insulated with foams. The panel gets up to 70 or 80 degrees at most, so my piping is more than adequate for this. The plastic piping is also much bettter insulated than copper pipe.
I have noticed now that I have a radiator in the system, there is quite a lot more water to heat up. The plus side of this is that when the sun does get going, as it did yesterday, when the pump switches on when there is sufficient differential, it circulates for much longer because there is a greater quantity of available hot water to exchange.
Before, with just the 10mm copper pipe, the heat would get sucked out of the plate quite quickly. This system now, though slower to respond, once it gets going seems to be doing a great job.
Early days, but I will know when the sun is a lot higher in the sky. The rate of temp rise yesterday was comparable almost with mid summer last year.
I have noticed now that I have a radiator in the system, there is quite a lot more water to heat up. The plus side of this is that when the sun does get going, as it did yesterday, when the pump switches on when there is sufficient differential, it circulates for much longer because there is a greater quantity of available hot water to exchange.
Before, with just the 10mm copper pipe, the heat would get sucked out of the plate quite quickly. This system now, though slower to respond, once it gets going seems to be doing a great job.
Early days, but I will know when the sun is a lot higher in the sky. The rate of temp rise yesterday was comparable almost with mid summer last year.
#37
- Group: Moderators
- Posts: 5159
- Joined: 18-July 06
- LocationGraham, NC USA
Posted 07 March 2012 - 14:43
Hey Chris,
I remembered that your system was a two stage/heat exchanger. The main reason I posted was to clarify the potential hazards if others were not aware. As to the precautions I mentioned, if you were to have a failure, these measures would minimize potential exposures, unlike several nuclear plant cooling designs we have seen fail, I prefer incorporating failsafes.
If your solar systems first stage were truly a closed loop, I would recommend changing the working fluid to a highly saline liquid as the sodium would improve heating and conductivity. As to the plastic tubing, generally most black tubing today is non-hygroscopic polyethylene, if you also employ high temperature stable, schedule 40-80, CPVC you generally can use a copper tubing preheating single stage panel interconnected via plastic pipes, with a thermally triggered bypass valve, (to insure sufficient temperature to minimize non-solar water heating, especially if you incorporate a single stage system with recycling).
(The problem is sometimes it is unclear if the hot water holding tank is actually a separate or two stage system versus a recycling one stage system. I have found it is always a good idea to test the division in the systems by adding a strong heat impervious dye to the first stage of the solar heat exchanger...)
I remembered that your system was a two stage/heat exchanger. The main reason I posted was to clarify the potential hazards if others were not aware. As to the precautions I mentioned, if you were to have a failure, these measures would minimize potential exposures, unlike several nuclear plant cooling designs we have seen fail, I prefer incorporating failsafes.
If your solar systems first stage were truly a closed loop, I would recommend changing the working fluid to a highly saline liquid as the sodium would improve heating and conductivity. As to the plastic tubing, generally most black tubing today is non-hygroscopic polyethylene, if you also employ high temperature stable, schedule 40-80, CPVC you generally can use a copper tubing preheating single stage panel interconnected via plastic pipes, with a thermally triggered bypass valve, (to insure sufficient temperature to minimize non-solar water heating, especially if you incorporate a single stage system with recycling).
(The problem is sometimes it is unclear if the hot water holding tank is actually a separate or two stage system versus a recycling one stage system. I have found it is always a good idea to test the division in the systems by adding a strong heat impervious dye to the first stage of the solar heat exchanger...)
#38
Posted 09 March 2012 - 22:16
You make your own risk assessment of course, but personally I wouldn't consider a solar system any greater risk than large parts of the rest of a HW system. It's regular use of the HW pipe network that I would imagine matter more to flush the system of any nasties.
After all, irrespective of any solar system, there are large parts of most domestic systems sitting at 20C or so:
- the bottom third of the HW tank after any draw-off
- the cold water tank in the loft in the summer months
- all the warm water pipe runs inside the house - particularly those to showers and baths.
Our's is a direct (open loop) Evacuated Tube system (10mm copper pipe). This time of year the panels can get the tank up to about 45 from about 25 degree start. The boiler does the rest if required (for 6 months of the year it's off most days). A decent day from April on, the panels would push the tank to 60C, and June-Aug they'd boil the tank if I let them - which we don't of course.
Here's an example from October last year:
(Black line - panel, blue - tank bottom, red - tank top, green - ambient. Boiler heater tank at 18:30)
After all, irrespective of any solar system, there are large parts of most domestic systems sitting at 20C or so:
- the bottom third of the HW tank after any draw-off
- the cold water tank in the loft in the summer months
- all the warm water pipe runs inside the house - particularly those to showers and baths.
Our's is a direct (open loop) Evacuated Tube system (10mm copper pipe). This time of year the panels can get the tank up to about 45 from about 25 degree start. The boiler does the rest if required (for 6 months of the year it's off most days). A decent day from April on, the panels would push the tank to 60C, and June-Aug they'd boil the tank if I let them - which we don't of course.
Here's an example from October last year:
(Black line - panel, blue - tank bottom, red - tank top, green - ambient. Boiler heater tank at 18:30)
Attached thumbnail(s)
This post has been edited by grahamread: 09 March 2012 - 22:36
#39
Posted 09 March 2012 - 22:33
...here's an example of Solar heating to higher temps in the late summer (15/09/11) and one day (02/09/11) when, due to the fact I'd set the thermostat wrong so it didn't stop heating and the tank was already hot from the day before, we had a "slight problem" with the tank at 87C ( 
oops) - it did eventually dump the hot water (15:00). It's a vented tank so no pressure issue. I've since changed the settings.
(I would point put we have mixer valves on the bath/showers)
oops) - it did eventually dump the hot water (15:00). It's a vented tank so no pressure issue. I've since changed the settings.(I would point put we have mixer valves on the bath/showers)
Attached thumbnail(s)
This post has been edited by grahamread: 09 March 2012 - 22:34
#40 Guest_Chris Lloyd_*
Posted 09 March 2012 - 23:36
Thanks for posting that info Graham. Those are some neat graphs. Reminds me of before I lost my last job. I used to set up 20 or so tc's or PT sensors to record temperature data. I used to live Excel macro's LOL, just to process the data.
I was never without my data logger.
How did you record these values?
Though I will never get the same kind of temperature rise as that I am quite chuffed that I have been able to make something myself, and for very little cost that goes a long way to heating the water. With the one panel I got a tank full of 37 or 38 degree water, which is great for a shower. If I wanted hotter water for washing up, then I would boil a kettle.
Hopefully now I will get more days when the water will warm to this temp and on sunny days I should hopefully get water up to 45 or so degrees.
Total outlay has been around 250 pounds ( Including solar controller and pump).
It's really sad I know, but on the 2 days in the last week when it has been sunny I have been keeping an eye on the tank. I got nearly a 3 degree temp rise in the one hour ( 11 til 12 I think). And that's the bottom of the tank where there is the majority of the cold water.
So once that sun is up another 25 or 30 degrees by mid summer it will make all the difference. It's 10 degrees higher just from the start to end of this month.
I was never without my data logger.
How did you record these values?
Though I will never get the same kind of temperature rise as that I am quite chuffed that I have been able to make something myself, and for very little cost that goes a long way to heating the water. With the one panel I got a tank full of 37 or 38 degree water, which is great for a shower. If I wanted hotter water for washing up, then I would boil a kettle.
Hopefully now I will get more days when the water will warm to this temp and on sunny days I should hopefully get water up to 45 or so degrees.
Total outlay has been around 250 pounds ( Including solar controller and pump).
It's really sad I know, but on the 2 days in the last week when it has been sunny I have been keeping an eye on the tank. I got nearly a 3 degree temp rise in the one hour ( 11 til 12 I think). And that's the bottom of the tank where there is the majority of the cold water.
So once that sun is up another 25 or 30 degrees by mid summer it will make all the difference. It's 10 degrees higher just from the start to end of this month.
#41
Posted 10 March 2012 - 00:13
Quote
How did you record these values?
They are recorded from 1-wire temperature sensors - I bought just the sensor (relatively cheap) and wired them up myself using a straw and some heat shrink tube to make a temperature probe; and telephone cable for the network. The sensors draw power from the 5v USB line from the computer.
Connects via USB (see above link) to a small cheap second-hand laptop running linux, digitemp and rrd database to record the data over 24 hrs.
The graphs I posted were from the windows os version of digitemp. Unfortunately my cheap second hand laptop gave up the fight after 3 years in the warm airing cupboard! I've switched to a small cheap eeepc running a version of ubuntu (linux), using linux version of digitemp. Graphs aren't quite as nice, but do the job (see below).
Quote
quite chuffed that I have been able to make something myself
Absolutely. I cheated and bought the EV tubes - although I did install it all myself and kept cost down by plumbing straight into an existing HW cylinder (i.e. no pressure stuff often required for closed loop systems).
Quote
It's really sad I know, but on the 2 days in the last week when it has been sunny I have been keeping an eye on the tank
In that case, judging by threads on other forums, there's quite alot of 'sad' people around the country doing the same! - that or watching their solar PV inverter
Can't beat a bath or shower in hot water that's been entirely heated by the sun!
Attached thumbnail(s)
This post has been edited by grahamread: 10 March 2012 - 00:30
#42 Guest_Chris Lloyd_*
Posted 25 March 2012 - 21:11
Well, my now 2 homemade panels got all 140 litres in my cylinder up from 16 degrees to 31 degrees yesterday. A very respectable 2,6 Kw/h of heat energy.
And it's only the end of March.
And it's only the end of March.
#43
Posted 26 March 2012 - 13:49
Chris Lloyd, on 25 March 2012 - 21:11, said:
Well, my now 2 homemade panels got all 140 litres in my cylinder up from 16 degrees to 31 degrees yesterday. A very respectable 2,6 Kw/h of heat energy.
And it's only the end of March.
And it's only the end of March.
Good stuff. The recent weather has been really good for HW and PV production!
#44 Guest_Chris Lloyd_*
Posted 26 March 2012 - 18:11
Cheers Graham - and thanks for your previous response ( I did read it at an earlier stage but forgot to reply).
I had to bleed a bit of air out of thr system today (it came on in the night when the frost protect cut in), the pump was starting to sound a little noisy. I clamber up in the loft with a hose pipe and fill it from there. I have a length of copper pipe around 20 cm in length at the top of the system with an isolation valve which collects air. I will get round to fitting an automatic air valve at some stage and plumb the inlet into the mains water so that I can top it up as and when.
Put the heating at 5pm so that young man could have a bath. With the entire tank at 33 degrees it took only 5 minutes to heat the head of water up to 50 degrees This is where the system really pays for itself - pre charging the water.
I had to bleed a bit of air out of thr system today (it came on in the night when the frost protect cut in), the pump was starting to sound a little noisy. I clamber up in the loft with a hose pipe and fill it from there. I have a length of copper pipe around 20 cm in length at the top of the system with an isolation valve which collects air. I will get round to fitting an automatic air valve at some stage and plumb the inlet into the mains water so that I can top it up as and when.
Put the heating at 5pm so that young man could have a bath. With the entire tank at 33 degrees it took only 5 minutes to heat the head of water up to 50 degrees
This is where the system really pays for itself - pre charging the water.
#45
- Group: Members
- Posts: 315
- Joined: 10-May 12
- LocationWorcestershire
Posted 24 July 2012 - 22:34
Well, in the warmest day of the year so far my 2 homemade panels heated my entire hot water cylinder to 56 degrees C. 52 yesterday. Used a lot of the water last night for a bath. Base of tank started at 24 C this morning, with a head of 37 degrees. So to heat the whole lot up again to 56 degrees - quite impressive from around 1.75m2 of solar collector ( 1 radiator and 1 flat panel collector).
Back in May when we had a few nice days the water got up to 51 degrees.
Just goes to show how a bit of DIY can work wonders
Back in May when we had a few nice days the water got up to 51 degrees.
Just goes to show how a bit of DIY can work wonders
