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Author Topic: Planing a CHP with Lister CS on waste oil  (Read 12229 times)
martin W
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what do you mean my snoring is too loud!


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« on: March 07, 2016, 07:45:34 AM »

Hello,

I'm finally getting closer to getting a CHP set up. But need some advice to clarify things. I've had a good read of some of other peoples CHP set ups and think I know what I want, but I don't really know what I need..... hence the questions.


Back ground
I live in suburbia in a semi detached 3 bed house. The shed for the CHP is around 20m away from house and 25m plus away from neighbour - no option to move it closer.
I currently have 2.8kW of PV on house.
I have (currently) a 172 Litre thermal store in my house attic which provides hot water and the central heating. The flow to the central heating system is reduced to 50°C via a mixing valve. Radiators have been size to use this lower flow temperature.
The thermal store is heated by a 30kW gas system boiler (down rated to 10kW - it was very cheap when my combi bit the dust!).
The thermal store is also heated by a 4kW Charnwood country 4 wood burning stove which gives around 2kW heat to the living room and 2kW heat to a back boiler connected to the thermal store.
The thermal store is also heated by Navitron 40x 47mm tube solar thermal system.
The thermal store is also heated by an immersion heater which is connected to a Solar iSave diverter controller which sends all excess PV production to the immersion heater in the store.


Loads in the house....
Heat load (losses) of the house - the boiler is currently connected to the boiler coil of the Navitron (Newark) thermal store. This I believe can only take around a 6-7 kW heat input. This would seem about right as the boiler is constantly cycling even with the reduced 10kW output.
The last heat loss I did on the house was around 21,000 btu's (6kW), which seems about right as the boiler does keep the house going if left on for quite a few hours..
Electric load - last time I check our overage was 300-500w with daily consumption around 8-10kWh.



1. I have a very good source of free waste oil. The only thing is I am unsure if it is suitable. It will be a mixture of coconut oil, cod liver oil, oil of evening primrose, and any other type of oil you could stick in a 'health capsule' (read cod liver oil capsule, etc.). The waste oil is poured into an IBC and should be fairly clean, but it is possible that there is some Industrial Mentholated spirits in it (tiny amount which I would expect would evaporate off before vessel is closed). The oil would have probable stood for around 1 month or more before I pump out oil for my use (I can't really transport and handle a 1000 litre IBC full of oil).

Q. Would this oil run a Liter CS. The oil would be of various different mixes each time I stock up...

Q. How much oil would I need a year? I would think I would run for 10 hours a day in the winter.... much less so during the summer. I assume around 1 - 1.5 litres of oil per hour running. I believe I could get as much as 5000 litres of oil 'free' per year, although I would expect to use 3000...


2.. Genset design - I was thinking along the lines of the Lister running an alternator which charges a battery bank which supply a grid tie inverter which is connected to the main fuse board and can supply the house (as well as the gird). This thinking is so that the battery can supply some night time electric….

Lister CS - Alternator/battery charger - battery bank - Grid tie inverter - house

Q. Can you get a battery driven grid tie inverter? Would it stay constantly on and provide 2kw to grid (if I'm not using anything) until it shuts down due to low battery state. Do they work differently to PV grid tie inverters?
Q. Would the battery driven grid tie inverter work OK with the PV grid tie inverted connected to same house circuits?

3. Heat capture and Storage from Lister – I believe that it is possible to get somewhere between 3 and 6kW of heat for the Lister (including exhaust heat exchanger).
Q. what is the ideal coolant water temperature to run the lister CS.
Q. what is the maximum coolant temperature to run the lister CS.
Q. can a car like thermostat be fitted to the lister CS to keep the enginer at the optimum temperature so you don’t over cool it?

 4. Heat storage – Heat dump. I am considering using a IBC which I would ply skin and insulate for heat storage as I can get it free. This is going to depend a lot on the max water temperature for running the Lister CS. I might go down a cylinder route if I don’t need too much water storage..
The storage at the shed would provide on demand heating to the thermal store in the house attic as that provides all the heating and hot water and already has multiple inputs.
Heat dump, in the summer I would dump heat from Lister to a pipe under my wood store….
Q. what the the max sensible temperature for an IBC – I’ve seen 110°C so I would assume 80°C would be fine. Does anyone have any experience.


Any advice welcomed on the proposed set up… the electric generation is my may area of concern...
« Last Edit: March 07, 2016, 07:48:43 AM by martin W » Logged

Woodstove owner since Feb 2011 Tongue (yes it's finally off the pallet)
Solar Water Heating since 17th March 2009, 2.94kW PV since Dec 2011
Chicken Owner - Self sufficient in chicken c*@p, boy watch those tomatoes grow. Allotment owner since August 2011
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oliver90owner
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« Reply #1 on: March 07, 2016, 08:13:44 AM »

Firstly check the noise (as in nuisance) level at the distances proposed.  Also check your deeds - mine include a limit on the size of any engine installed on the property!  The CS exceeds the limit on mine.  The engine needs to run at close to the boiling pointof the coolant (not plain water, I would suggest), so 90 degrees Celsius is a good target.  Also remember that the CS was not designed for a pressurised system.

I will leave it at that for the moment as I believe you may want to think again, if there is any likelihood of complaint from your neighbours.
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martin W
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what do you mean my snoring is too loud!


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« Reply #2 on: March 07, 2016, 09:19:39 AM »

Hello,

noise won't be an issue, it will be a fully sound proof shed. Will dig appropriate trench and baffles for exhaust. Only run during daytime...

Neighbour had cockerel... so no complaints there... bloody thing went off at 3 am in summer... well before dawn.

Never heard of a limit on deeds for an engine?Huh Nothing on mine except usual to allow access, etc.
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Woodstove owner since Feb 2011 Tongue (yes it's finally off the pallet)
Solar Water Heating since 17th March 2009, 2.94kW PV since Dec 2011
Chicken Owner - Self sufficient in chicken c*@p, boy watch those tomatoes grow. Allotment owner since August 2011
Now an Lister wannabie Tongue
jotec
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« Reply #3 on: March 07, 2016, 09:25:47 AM »

I have decommissioned our lister CHP but it ran the house for 5 years. I now have solar and a lister som for direct electric.

A few observations.

As stated they are not quiet though can be quiet enough if the enclosure is very well sound insulated, a silencer is on the inlet and a good exhaust pit is used to silence the exhaust. A friend has his a few yards from his house on an estate with no problems.

They run and start on veg oil, I have a heater on the high presure line from the injector pump and a glow plug in the compression change over valve. A coil in the fuel tank heated the oil there. The oil is filtered before use.
I fitted a starter motor to make starting easy, a transit starter motor belt driving the flywheel with a one way bearing on the starter motor.

As stated there should be no head on the cooling water and with thermo syphon I had no problem with over cooling. I pump the water from the cooling tank through a heat exchanger to the radiators. I have a heat exchanger on the exhaust to capture heat from there

The electrical side was a SMA windyboy grid tie inverter driven from a 3 phase wind turbine pma rectified to give 2kW at 300V.

If you are interested the turbine and GTI on the bay.

HTH
« Last Edit: March 07, 2016, 09:47:27 AM by jotec » Logged

Aiming to reduce dependency on 'mains energy'. Own bio for 120k miles, solar water heating (DIY),  CHP done, Solar PV, use wood cut from own trees.
In U.K. near Worcester
knighty
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« Reply #4 on: March 07, 2016, 11:58:21 AM »

rule of thumb for a diesel engine is 1 pint of fuel per 1kwh electric output

rule of thumb for output is you'll get 1/3 electric, 1/3 heat into coolant and 1/3 heat out the exhaust



personally, I'd drop the idea of the battery bank and just run straight into a grid tie inverter - a lot less hassle and a lot less maintenance

if there's anything you want to run from batteries just buy a small UPS for each thing and then plug it in with a timer pug so it's only connected to the mains when you expect the generator to be running
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spaces
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« Reply #5 on: March 07, 2016, 03:37:41 PM »

In no particular order, here are some thoughts:

Check your oil is going to burn well in the cylinder(s). If you're not running the Lister 24/7 what sort of temps does it become too gloopy to flow well enough for your needs and how well is the Lister going to start on a cold winter's morning?
Go overboard on silencing the noise, be aware that the lowest frequencies can appear to grow louder the longer something is running. Build the gen shed and have it running before buying and installing the rest of the system, in case there is a problem with people living nearby.
Plan the refuelling and fuel storage so there is no chance of rats and other vermin chewing their way into it, or congregating where it's warm and cosy.
Plan the refuelling so there is the minimum effort required on your part and small spills can't accumulate where they're difficult or impossible to clean up properly.
I'd do without a large battery bank if you remain connected to the mains but I would consider having something small, sufficient to run LED lighting, a laptop and phone/tablet chargers for a few hours.
Rather than dumping excess heat in summer, why not have a heated swimming pool or hot tub?

« Last Edit: March 07, 2016, 03:58:39 PM by spaces » Logged

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TurnkeyVegSets
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« Reply #6 on: March 07, 2016, 04:27:53 PM »

Hi Martin,

There are many topics to cover here and many calculations to do before you dive in. I've got a spreadsheet for most of this, so I can help, but in the meantime I'll give you my views on your questions.

Q1 Would this oil run a Lister CS. The oil would be of various different mixes each time I stock up...

The quick answer is 'yes', but you're wanting long term reliability, so I'd recommend the following:-
- compare the viscosity of your fuel with regular diesel (drill a small hole in a lid of a plastic container, put your fuel in, turn upside down and time how long it takes to empty. Do the same with diesel). If your fuel is significantly slower to empty, consider diluting with kerosene. I highly recommend using a glow plug to help start the engine. Please note though that although most glow plugs are designed for automotive 12vdc systems, they are not rated for 12 volts. In a car four of them come on at the same time plunging the system voltage. Rated voltages are usually visible on the glow plugs and I've yet to find one over 11 volts. So one glow plug powered by a 12 volt battery will have a much shorter life than four of them. Add a resistor to lower the voltage.
Fish oil has caused big problems for me in the past. Check the fuel isn't sticky. If it is, don't put it in the engine.

Q2 How much oil would I need a year? I would think I would run for 10 hours a day in the winter.... much less so during the summer. I assume around 1 - 1.5 litres of oil per hour running. I believe I could get as much as 5000 litres of oil 'free' per year, although I would expect to use 3000...

This is one of those things that needs calculating. It is of course a function of engine load, so this should be revisited after answering some of your other questions.

Q3 Can you get a battery driven grid tie inverter? Would it stay constantly on and provide 2kw to grid (if I'm not using anything) until it shuts down due to low battery state. Do they work differently to PV grid tie inverters?
Q4. Would the battery driven grid tie inverter work OK with the PV grid tie inverted connected to same house circuits?

This can all be done/purchased, but lets look at some other factors first.
If you're going to be grid-connected all the time, you might want to consider not having batteries. This will simplify your system and reduce costs significantly. I would recommend not using an alternator, but rather a standard 2kW electric squirrel cage motor (4-pole) acting as an induction generator. You can then use this to start your engine too. You'll need a mains protection relay in this scenario that satisfies G83 regulations. Unfortunately there are no G83 available as discrete off-the-shelf items. Grid-tied inverters have them built in. G59 relays cost £500, but I may have sourced a relay from abroad that appears to satisfy G83 without the G59 price tag.
If you're going down the battery bank route, don't use lead-acid batteries. They need to be kept charged or they will age, but you need them to be discharged before your solar PV sees the sun or that power gets wasted. Also, lead acid batteries don't work well with CHPs. The bulk charge phase is short and your engine spends most of its time under-loaded.
Lithium Iron Phosphate batteries (that's iron not ion) are far superior.
Another option would be to use a DC generator head. There are plenty of Wind turbine DC generators available and plenty of DC electric motors. This option allows power to be take from your CHP and batteries at the same time, which means your battery bank can be much smaller.
One of the Indian manufacturers is offering a Petter-based DC generator. They are a bit pricey though, but you can pressurise the Petter coolant.

Q5. what is the ideal coolant water temperature to run the lister CS.
It depends on the Lister engine manufacturer. The hotter the engine runs, the more efficient it is up to the point where the piston has expanded so much that friction starts to kick in and slow the engine down. Different piston diameters and materials affect the maximum running temperature. The original cast iron piston is great. I've seen an engine run dry and the head got so hot that the paint burnt off. It eventually seized, but once it had cooled down, it started again. I'd aim for 95 degrees.
Q6. what is the maximum coolant temperature to run the lister CS.
See above.
Q7. can a car like thermostat be fitted to the lister CS to keep the enginer at the optimum temperature so you don’t over cool it?
Yes. Stationary engine parts used to sell these (as well as glow plugs in the compression ratio plug).

Hope this helps,

     Mark


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jotec
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« Reply #7 on: March 07, 2016, 04:39:15 PM »

As suggested in the above post a hot tub makes an ideal heat dump for summer running, that is what I use. It has a heat exchanger in it and the water from the cooling tank is circulated through it.
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Aiming to reduce dependency on 'mains energy'. Own bio for 120k miles, solar water heating (DIY),  CHP done, Solar PV, use wood cut from own trees.
In U.K. near Worcester
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