Must Get A Life!

[OnOff]

towel rad good idea, but you never have one when you need one!!

Got up last night for a leak as you do when getting on and having sunk a few Magners....................Walked into the en suite and the HEAT hit me!. I'm thinking "I know it's been a warm day but this is ridiculous!".

Did the business and a tad unsteady LENT against the oil filled 'effin TOWEL RADIATOR!!! The thing hasn't been switched on in probably 20 years YET yesterday she decides to "see if it still works" and forgot it was on! Nice burn on the wrist.

if you have all the air out of that pipe then it should work, but any air in it and it wont

Fingers crossed the Jubilee clip is tight then!

 

[OnOff]

Seems to be working...................measured the outlet temp when I first filled the system at at nom 26degC...........................then 39degC................now 41deg after 45 minutes:

 

[steptoe]

What was the temp in the barrel?

Thats the important bit, to see if the water is circulating.

Looking good though,

 

[OnOff]

What was the temp in the barrel?

Thats the important bit, to see if the water is circulating.

Looking good though,

Didn't have it going for long enough (sun went down) to get the barrel hot. That's this weekend's  "to do". If no joy then I might investigate smaller dia tubing - using 1/2" garden hose at the mo with 20mm bore insulation and or a pump. It's quite impressive though just feeling the inlet and outlets by hand and noting the considerable difference.

 

[steptoe]

Im just wondering if convection will allow the hot water to drop past your high point if you are not actually syphoning,

and simply using thermal syphon.

 

[OnOff]

OK, this mornings efforts. I had the panel covered over with an old ply sheet last night just in case one of the kids tripped and fell through the glass last night when they were out slugging with the torch.

So from 10.00hrs this morning. Set the panel up facing the sun etc. A few results all taken in direct sun:

Time             Temp at Outlet         Temp at Tank

10.00                  26.8                          -                  

10.05                  27.9                          -

10.25                  28.3                          -  

10.33                  31                             -

10.45                  38.4                        22.9

10.52 (cloudy)     39.6                        23.2

11.03                  44.9                        24.1

11.16                  51                             -                         

11.23                  55                             -

11.38                  60.3                          -

11.48                  64                             -

I've laid off of the tank measurements for a reason - basically I've not quite figured out "how to". To get the measuring probe in I driled a 4mm hole in the lid next to the "M20 gland" hose entry. So I'll have heat escaping from there. The 3 measurements between 10.45 & 11.03 weren't "jumping" as quick as those at the outlet. What I was in fact doing was inserting the probe TOO FAR into the as yet "unwarmed" zone. Withdrawing the probe into the "upper" layer of the tank water and the temperature was circa 5degC higher. I'll see how hot the water in the barrel is at the end of the day. Another factor to consider is that the dark red barrel itself is in direct sunlight so will be gaining from that.

A few things to consider. Obvious losses via the tank skin so that needs insulating. The exposed copper at the panel outlet is wasting heat (in fact now far too hot to touch). The exposed copper at the tank entry again needs insulating. I'm also going to change the bottom panel entry to a right angled fitting there ans again insulate.

But overall the system I think proves my panel design and the day is far from over. I can happily feel the heat rising UP the insulated hose pipe going to the top of the tank - even through the insulation.

"Probe fully inserted":



"Withdrawn"



En route to the NOW 66degC:



Any suggestions as to the best orientation angle for the panel to the sun?

Off now to insulate some "lossy" bits and see if we can hit 70degC!

Cheers

 

[OnOff]

Now 72 DegC at the panel outlet - 13.24hrs

 

[steptoe]

about 30 degrees seems about the right angle,

i think,

im still not sure about your convection being able to go 'down' into the tank is efficient,

is the lid in line with the tap?

could you put the barrel on its side?

[btw, typed on my 'new' shed laptop I got given as it point blank refused to run windoze on the replacement screen I fitted in it for a friend, so they bought a new one and gave this to me, screen price-42£,   HP dual core with 4G ram ]

OK,

looked at the pix better, could you reseal the temp hole in the lid and put the barrel on its side with the tap at the bottom?

I think that with help your convection/thermal syphon immensely.

remember, your outlet [hot] must always flow upwards, atm you are needing it to flow down into the tank,

if you syphon normally this will work, but will need a manual start,

for natural thermal syphon the current set-up wont work, the way I understand it anyways, but, I could be wrong, see name tag  :|

 

[OnOff]

about 30 degrees seems about the right angle,

i think,

im still not sure about your convection being able to go 'down' into the tank is efficient,

is the lid in line with the tap?

could you put the barrel on its side?

[btw, typed on my 'new' shed laptop I got given as it point blank refused to run windoze on the replacement screen I fitted in it for a friend, so they bought a new one and gave this to me, screen price-42£,   HP dual core with 4G ram ]

OK,

looked at the pix better, could you reseal the temp hole in the lid and put the barrel on its side with the tap at the bottom?

I think that with help your convection/thermal syphon immensely.

remember, your outlet [hot] must always flow upwards, atm you are needing it to flow down into the tank,

if you syphon normally this will work, but will need a manual start,

for natural thermal syphon the current set-up wont work, the way I understand it anyways, but, I could be wrong, see name tag  :|

I'll take all that on board. If I do lay the barrel down then I'll maybe use a new lid and a proper "tank" type connector. Panel outlet at about 82 degC now, water temp in top of tank mid 30's:

 

[Andy™]

big temp difference, maybe not enough flow?

 

[steptoe]

would agree Andy, I think the tank is simply rising due to its own absorbed heat,

any idea what the temp at the top of the return pipe is?

as I said, the alternative is to manually syphon the flow, that would work the way it is.

 

[Marvo]

Any suggestions as to the best orientation angle for the panel to the sun?

Can't you use one of those solar PV output prediction programs where you input you location and your roof direction and angle? Play around with different orientations, I'm sure if you find the optimum PV panel orientation it will be the same for your water heater. 

 

[OnOff]

big temp difference, maybe not enough flow?

Yep, agreed. Seems a waste not to be getting it to the water maybe. I'll take on board the comments about lying the barrel on its side etc and go from there.

Not sure whet I'll get done tomorrow as I've got to get 4 push bikes serviced inc doing at least one puncture, do the exhaust shield on the car and dig out and shutter for an 8' x 10' shed base! 

would agree Andy, I think the tank is simply rising due to its own absorbed heat,

any idea what the temp at the top of the return pipe is?

as I said, the alternative is to manually syphon the flow, that would work the way it is.

Yep, my thoughts simply hot air rising up the pipe.

 

[steptoe]

did you prime the system?

ie, ensure ALL the pipes were completely full of water?

otherwise you will simply have an airlock, and it will never work, either via thermal syphon or manually

 

[Marvo]

I'd suggest keeping pipe lengths between the panel and the tank asshort as possible and maybe larger diameter. 

 

[OnOff]

did you prime the system?

ie, ensure ALL the pipes were completely full of water?

otherwise you will simply have an airlock, and it will never work, either via thermal syphon or manually

Um...................I thought I had but maybe without understanding quite what that entailed!  :coat  Take me through it please!

Anyway, fed up with this seeming lack of flow I just took out the top pipe from the barrel with the intent of dropping it LOWER than everything else to manually start things off then quickly putting it back in the tank. Sort of forgot it might be HOT water and sure enough................nigh on scalded my hand!

Temp at panel outlet down to circa 35degC

I'd suggest keeping pipe lengths between the panel and the tank asshort as possible and maybe larger diameter. 

Now then, others reckon SMALLER dia, like 8 or 10mm?

 

[Andy™]

Um...................I thought I had but maybe without understanding quite what that entailed!  :coat  Take me through it please!

Anyway, fed up with this seeming lack of flow I just took out the top pipe from the barrel with the intent of dropping it LOWER than everything else to manually start things off then quickly putting it back in the tank. Sort of forgot it might be HOT water and sure enough................nigh on scalded my hand!

Temp at panel outlet down to circa 35degC

Now then, others reckon SMALLER dia, like 8 or 10mm?

no, bigger is better. less resistance in the pipework to block the flow

your problem is any potential air at the top of the pipe, if there is any, it will limit / stop the water flowing

 

[OnOff]

Um...................I thought I had but maybe without understanding quite what that entailed!  :coat  Take me through it please!

Anyway, fed up with this seeming lack of flow I just took out the top pipe from the barrel with the intent of dropping it LOWER than everything else to manually start things off then quickly putting it back in the tank. Sort of forgot it might be HOT water and sure enough................nigh on scalded my hand!

Temp at panel outlet down to circa 35degC

Now then, others reckon SMALLER dia, like 8 or 10mm?

Anyway, by my reckoning it's MAGNER's O'CLOCK!  Guinness  

 

[Marvo]

If you're aiming to achieve circulation by natural convection caused by water density differences due to temperature gradient within the tank then larger bore and shorter pipework would present less resistance -> more flow. Also shorter pipes would be easier to reduce losses by insulating.

 

[steptoe]

ok,

syphoning of any sort requires that all pipework is completely free of air, the liquid must comprise 100% of the pipework,

smaller diameter was my thoughts for manual syphoning, to allow the water to gain a large enough temp rise in the solar chamber,

using thermal syphoning it may well work better the other way round, ie, larger pipework.

either way,

I still think you really need to have all pipework lower than your head of water using thermal syphoning,

manual syphoning will not matter about this.