navitron
 
Renewable Energy and Sustainability Forum
Welcome, Guest. Please login or register.

Login with username, password and session length
News: Anyone wishing to register as a new member on the forum is strongly recommended to use a "proper" email address - following recent spam/hack attempts on the forum, all security is set to "high", and "disposable" email addresses like Gmail, Yahoo and Hotmail tend to be viewed with suspicion, and the application rejected if there is any doubt whatsoever
 
Recent Articles: Navitron Partners With Solax to Help Create A More Sustainable Future | Navitron Calls for Increased Carbon Footprint Reduction In Light of Earth Overshoot Day | A plea from The David School - Issue 18
   Home   Help Search Login Register  
Pages: 1 [2] 3   Go Down
  Print  
Author Topic: Off-grid Immersion thinking.  (Read 59229 times)
Fionn
Hero Member
*****
Offline Offline

Posts: 540


« Reply #15 on: May 13, 2015, 12:32:50 PM »

A great result for your system Biff.
So if I understand it correctly you have both PV and Wind connected directly to your battery bank with a DC immersion heater acting as a dump load (controlled by Chinese controller).
When the tank gets hot at the top you start a destrat pump that circulates the water throughout the tank to even out the temperature.
When the whole tank gets very hot the central heating circulation pump kicks in and moves heat from the tank to your rads.
Presumably you are just using normal tank stats for the last 2?
Logged

PV - 2.75kW East, 1.5kW South, 2.5kW West. 3 x Flat Plate Solar Thermal with side arm FPHE on 268L cylinder
biff
Global Moderator
Hero Member
*****
Offline Offline

Posts: 11877


An unpaid Navitron volunteer who lives off-grid.


« Reply #16 on: May 13, 2015, 01:06:17 PM »

That is exactly it Fionn,
                 And right again about the last two stats, However, the stat triggers the domestic water circulation pump is a remote boiler type with the sensor placed deep down in the sheath between the immersion tongs. The control to adjust the temp setting if necessary, is out in front where we can reach it easily. So far we have not had reason to go near it.
  The C/H pump is triggered by two ordinary pipe stats, one on the normal expansion pipe from the boiler and one on the domestic water cooling return pipe to the top of the tank.
  There is a further second C/H pump,set to start up at a slighly higher temperature. It is plumbed in next to the water heater /storage tank in the hall which has its own 2kw immersion heater. All the pumps  become ac dump loads themselves. The pump in the Hall seldom activates and if it does,it means that the ordinary house C/H pump has gone awol or some thing else is wrong.It can deal with it.
  I use ordinary Chinese wind./solar hybrid controllers and bypass their dump loads to connect to the house dc immersions. Very simple and straight forward, using as many controllers as necessary and not a Sunny boy in sight. Grin
                        Biff
« Last Edit: May 13, 2015, 06:27:15 PM by biff » Logged

An unpaid Navitron volunteer,who has been living off-grid,powered by wind and solar,each year better than the last one.
andygo999
Newbie
*
Offline Offline

Posts: 26


« Reply #17 on: August 02, 2015, 12:57:08 PM »

Hi Biff
Thanks for posting this - interesting thread.
You've been kind enough to reply to my thread about ufh and issues I'm having with my store.
I've been wondering if it's possible yet to connect a wind turbine directly to the immersion on a thermal store? I'm at the top of a very windy hill. I like the idea of a small charge going into the store - especially over the shoulder seasons when the Rayburn isn't going flat out. Maybe I could sawp the immersion which is leaking on my store. Could you pm me details of your system
Andy
Logged
biff
Global Moderator
Hero Member
*****
Offline Offline

Posts: 11877


An unpaid Navitron volunteer who lives off-grid.


« Reply #18 on: August 02, 2015, 04:10:48 PM »

Hi Andy,
        Well first things first, I am off-grid and have been for over a decade, I started off with a small turbine to learn how they work and to get to know the right way to go about it.
  Our dc voltage is 120v ( 95% of our off-grid members are 48vdc)and our storage is 60 forklift battery cells, Approx 2 ton. Our dump load voltage is 138.9vdc and besides having our turbine delivering 1.5kw approx in a decent force 6/7 ,we aqlso have 3.8kw of pv. Our dump loads are 2 x dc 138vdc ummersion heaters, One in each tank. One in the DHWT and One in the water storage/heater tank, These Dc dump load immersions cannot be fitted with cutout thermostats, because the turbine depends on them for braking and preventing overspeed,
    The Controllers are simple Hybrid wind and solar controllers,,each capable of handling 2kw+ each, We have 4 strings of 120v PV 2 strings for the water storage/heater tank and 2 strings + the turbine for the other tanks, In the stormy weather, the turbine can fill the clock @ 1.6kw and stay there for days, One immersion is a little later coming onstream than the other, so they don,t both hit on the Turbine at the same time and it does not slam to a stop,instead it seems to have a nice light touch,yet keeps up speed and generating. Our previous controller from years back, used to slam on the brakes and discharge the bank for about a minute before levelling out @130v and then start going like the clappers straight into overspeed again and again. So the present controllers are a fantastic improvement and make the whole show run smooth even in the toughest conditions.
   The PV is briliant and very easy managed. i would start with a small turbine, something around say 600watt to 1000watt and learn to fly that. If you are on grid you would need some other type of arrangement to mine but a lot of the members have such systems that can handle grid tied inverters etc,
                                 It is all good, but just remember that you are dealing with electric cables and inverters and such, so you have to be really careful and not take chances. Just train yourself not to gamble and take chances and you will get there without a bother. There is all the help you need here on Navitron and many of the members are much better able to keep you in the right track than i am so we can all help. Wind turbines are highly addictive and once you get to know them,you are hooked for life. You really get to love them as they work through the gales and the lashing rain to deliver the power when you need it. So spending a few hours now and then maintaining them is a genuine pleasure.
  I hope this helps,
                       Biff
Logged

An unpaid Navitron volunteer,who has been living off-grid,powered by wind and solar,each year better than the last one.
andygo999
Newbie
*
Offline Offline

Posts: 26


« Reply #19 on: August 03, 2015, 10:36:02 PM »

Hi Biff
Thanks for the reply. Your system sounds great (even though you lost me on some of the details) but it's something I'd like to aspire to one day.

For now as you say I'd like to start small and keep it simple. Maybe this is too simple, but what I'm wondering is if it's technically possible to connect a small turbine DIRECTLY to the thermal store immersion to provide a constant trickle charge - which in our case could help keep our underfloor heating going. Ideally the system would consist of just the turbine and the store (which is a 277 litre Gledhill). If that's not possible perhaps we could use a battery in the system, but only as a buffer between them. For the moment I'm not looking to generate electricity for anything else or tie into the house system.

If the wind really blows and starts to heat up the store the CH system can kick in....

I've got a mate who's an electrician and done some pv installs. He's never done wind turbines though...
Is any of this feasible do you think?

Andy
Logged
biff
Global Moderator
Hero Member
*****
Offline Offline

Posts: 11877


An unpaid Navitron volunteer who lives off-grid.


« Reply #20 on: August 03, 2015, 11:17:35 PM »

Yes it is feasible Andy,
                 AG (Agrarian)has such a system in which the working go right over the top of my head. He did explain it to me but I forget now exactly how he did it. I know that he split the phases and heats water with one of his turbines. He does visit us on a regular basis and is never less than helpful. ( He keeps me on my toes as well)
                                                                          Biff
« Last Edit: August 03, 2015, 11:22:07 PM by biff » Logged

An unpaid Navitron volunteer,who has been living off-grid,powered by wind and solar,each year better than the last one.
Stig
Sr. Member
****
Offline Offline

Posts: 452


« Reply #21 on: August 04, 2015, 07:57:19 AM »


For now as you say I'd like to start small and keep it simple. Maybe this is too simple, but what I'm wondering is if it's technically possible to connect a small turbine DIRECTLY to the thermal store immersion to provide a constant trickle charge -

What's going to happen to the turbine when the water's hot and the thermostat switches off the load?  It'll need a dump load else...  sh*tfan
Logged
biff
Global Moderator
Hero Member
*****
Offline Offline

Posts: 11877


An unpaid Navitron volunteer who lives off-grid.


« Reply #22 on: August 04, 2015, 08:31:41 AM »

Good morning Stig,       
                    In our own System,where we have 2kw dc dump immersions in each of our two tanks, I don,t have a cutout switch on the immersions. Instead, I keep the head of the DHWT cool by drawing off the hot at the top down through the solar coil at the bottom and pumping it back up,cooled to the top,so that i eventually get a tank with the water temperature the same all over. At that point a stat on the return pipe to the top of the tank,triggers the c/h pump and the boiler coils exchange the heat in the tank for the cold water in the C/H system.
   You are right. We cannot have the turbine without a load. Our system seems to work well and the rads get hand warm on windy sunny days which means that the 500ltrs approx of water is sitting toasty roasty and will provide background heat well into the early hours.
                                                                          Biff
Logged

An unpaid Navitron volunteer,who has been living off-grid,powered by wind and solar,each year better than the last one.
andygo999
Newbie
*
Offline Offline

Posts: 26


« Reply #23 on: August 04, 2015, 08:36:02 AM »

Does it though....? I was only planning on using a small turbine and there's an awful lot of water to heat...
And the CH heating would kick in long before the store got hot enough to go bang...
Besides surely there must also be ways of turning a turbine out of the wind to switch it off.......
Having said that I know nothing so I'll start investigating dump loads......  

Thanks for the tip about Agrarian Biff, I'll have a search around some of his posts
Logged
billi
Global Moderator
Hero Member
*****
Offline Offline

Posts: 8923



WWW
« Reply #24 on: August 04, 2015, 08:42:48 AM »

as far as i know  a turbine direct  attached to an ac immersion , will not work  good and the turbine gets stalled ......
Logged

1.6 kw and 2.4 kw   PV array  , Outback MX 60 and FM80 charge controller  ,24 volt 1600 AH Battery ,6 Kw Victron inverter charger, 1.1 kw high head hydro turbine as a back up generator , 5 kw woodburner, 36 solar tubes with 360 l water tank, 1.6 kw  windturbine
biff
Global Moderator
Hero Member
*****
Offline Offline

Posts: 11877


An unpaid Navitron volunteer who lives off-grid.


« Reply #25 on: August 04, 2015, 08:58:10 AM »

            "And the central heating pump would kick in long before...."
        Hi again Andy, That is exactly what i thought until the steam came out the taps and Mrs Biff said,,"Ere  do you see this"
 Our immersion was 18" down from the very top of the tank, the boiler coils were another 6" of cold water below that and the stat on the expansion pipe for the boiler would never have triggered, so a proper sensor had to be fitted inside the sheath at the top inside the immersions tongs themselves.
  I have matched the dump load immersion voltage of 138/9 to the turbine,One in each tank but with over 150ft of a difference in cable length to the controller,so one immersion kicks in later than the other The two do not hit on the turbine at the one time during windy weather or at night. However,the PV can stall the turbine during the sunny weather when the bank is full.
  Unfortunately there is no way around that, unless you get all fancy and interesting but at the end of the day, it is like carrying buckets of water from the well, The color of the bucket could be more pleasing to the eye but it will not help you hump the buckets any easier( I could be wrong) freeze
                                                                                  Biff
Logged

An unpaid Navitron volunteer,who has been living off-grid,powered by wind and solar,each year better than the last one.
andygo999
Newbie
*
Offline Offline

Posts: 26


« Reply #26 on: August 04, 2015, 09:15:41 AM »

            "And the central heating pump would kick in long before...."
        Hi again Andy, That is exactly what i thought until the steam came out the taps and Mrs Biff said,,"Ere  do you see this"
 

Ha, that made me laugh....



The immersion on my store is close to the bottom, so i figured there would be alot more water to heat, it's also below the CH stat so in theory that should act as a failsafe.....but yeh point taken, I've no desire to create a hot water bomb....just wondering really what's feasible for my situation.
I'd like to dip my toe in the water re wind turbines (and keep it fairly cheap) but without having to go full on with batteries and connecting it to the rest of the house.

I guessed I'd have to swap the immersion for DC (though don't know much more than that). But am having to drain the system anyway to flush it, so might as well take the opportunity
Logged
billi
Global Moderator
Hero Member
*****
Offline Offline

Posts: 8923



WWW
« Reply #27 on: August 04, 2015, 09:21:11 AM »

andy , what kind of a  off grid system do u have ore aiming to have
Logged

1.6 kw and 2.4 kw   PV array  , Outback MX 60 and FM80 charge controller  ,24 volt 1600 AH Battery ,6 Kw Victron inverter charger, 1.1 kw high head hydro turbine as a back up generator , 5 kw woodburner, 36 solar tubes with 360 l water tank, 1.6 kw  windturbine
andygo999
Newbie
*
Offline Offline

Posts: 26


« Reply #28 on: August 04, 2015, 10:12:46 AM »

Hi
Not really off grid at the moment. We don't have gas (rural location) so heating is done via solid fuel Rayburn connected to a thermal store. There's also a woodstove in the lounge.

I'd like to install PV, but the start-up cost is too much for us at the moment sadly.

I'm just looking for ways of keeping our thermal store hot....

Solar thermal panels are one obvious way but I'm also looking at ways of utilising the immersion on the thermal store - maybe by connecting a wind turbine  (which is why I posted on this thread)...
Logged
biff
Global Moderator
Hero Member
*****
Offline Offline

Posts: 11877


An unpaid Navitron volunteer who lives off-grid.


« Reply #29 on: December 19, 2015, 09:10:04 AM »

Our 138vdc immersions are proving their worth,
                                       It may be miserable,windy and wet outside but inside is warm and cosy, Our two tanks are full of nice hot water,total capacity just under 500ltrs, One tank downstairs in the hall and the other upstairs in a hot press/mini kitchen. This morning the hot water was circulating in the DHWT and the return pipe to the top was the same temp which means that the excess hot was being pumped into the big underfloor pipes down stairs. So it is a system that looks after itself pretty well.
  We did leave the little stove on late, last fire was around 12pm but still the immersions work very nicely along side it,taking up the slack.
 The beauty of this system is that it takes the excess PV also and automatically,looks after everything itself.
 I hope this does not sound like I am blowing my trumpet here but instead, I recommend this system to anyone who is thinking of going down the same road.
 It is very good.
                 Biff
Logged

An unpaid Navitron volunteer,who has been living off-grid,powered by wind and solar,each year better than the last one.
Pages: 1 [2] 3   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.20 | SMF © 2013, Simple Machines
SMFAds for Free Forums
Simple Audio Video Embedder
Valid XHTML 1.0! Valid CSS!