Newbie From Australia

[AUSSIEGEORGE]

Hi Guys Newbie here, love reading all your topics you guys are so much mre advanced in your heating then we are in Australia.

I currently have electric heating I live in a farm house with 500 acres of woodland so plents of hard wood to burn.

In Australia the wood fires with wetbacks are small and they are used as an nstant type heat for example the boiler holds 50 litres of water once the 50 litres heatd up its pumped to wall radiators NO STORAGE if the fire goes out the heat stops.

I want to hve storage like you guys seem to have.

I have a few questions
that i hope some one can answer

1. I plan to have 1,000 litres of storage which is fed from a 50 kw boiler the water in the tank will be heated from thermosiphon into the tank

1.My questions are do I then pump water from the top of the tank to go into my radiators?
2. how does the water mix inside the tank does it need to be mixed or will hot water keep rising until all the water in the tank is hot?
3. Where would I put the probe in the tank to tell the boiler to stop firing top middle bottom?


Thanks and Gday from Australia.

 

[hobbyheater]

1. I plan to have 1,000 litres of storage which is fed from a 50 kw boiler the water in the tank will be heated from thermosiphon into the tank

Welcome to " HEARTH" !

Hot Water Storage
For the best results, the use of a heat storage tank is recommended. A properly sized storage tank
can cut wood consumption by as much as 40%. Hot water storage allows the boiler to run at optimum
capacity regardless of the demand for heat from the building being heated. The stored heat can be
recovered later, both stretching the time between boiler re-fuelings, and as an additional source of
heat on very cold days. Generally, the bigger the storage tank the better, as the boiler is most efficient
when running at full capacity. The rule of thumb on tank sizing is that 13 gallons of water can store
about 1KW of boiler heat. Using the EKO 25 as an example: 13 gal/1KW x 31KW = 421 gallons, 421
gallons x 91% efficiency = 383 gallon minimum size water tank. A hot water storage tank connected to
an EKO boiler can also be used to store hot water from a solar water heater.

The above is the section on sizing your storage from the EKO manual.
I have used thermosiphon in the past but you need very large diameter piping to make it work 3"to 4"or even larger for a 50 kw boiler and the lowest part of storage has to be higher than the top of the reservoir of the boiler. I now use a circulator and 1" copper between storage and the boiler.

On the radiators a second circulator is required.
The water inside the storage will stratify nicely.
Three probes in the storage gives the best temperature information; bottom, middle and top. For a metal tank, I think you can now get magnet type sensors.

 

[Eric Johnson]

Yes, welcome!

I assume you're talking about pressurized storage vs. non pressurized storage. That's probably the best way to go. And yes, you draw from the top of the tank, return water goes into the bottom. Something closer to 2,000 or even 4,000 litres would probably be optimum. Over here, we used old propane tanks, which come in various sizes and are pressure vessels, even when no longer used for gas. One thing about large-volume pressurized storage is that you need a big (read: expensive) expansion tank of some sort. What kind of boiler are you thinking of buying?

 

[AUSSIEGEORGE]

Thanks Eric and hobby heater please see attached the boiler I am looking at not as good as the ones you have in US i plan to hok it up to a vented storage as pressurized seem to dangerious for a DIYer.

A well insulated 4,000 litre tank connected to this heater burning good dried hard wood how long should it take ball park of course??

What flow rate beetween boiler and tank should i be looking for?

 

[hobbyheater]

1. I plan to have 1,000 litres of storage which is fed from a 50 kw boiler the water in the tank will be heated from thermosiphon into the tank

When you say " Thermosiphon" ! Does it mean to have the water circulate between the boiler and storage with no pump ?

 

[AUSSIEGEORGE]

Yes you are right I have been told to do it this way incase power goes out which it does sometimes

 

[hobbyheater]

Yes you are right I have been told to do it this way incase power goes out which it does sometimes

Using thermosiphon (gravity) does work. I have done it with a previous boiler. There is however a downside to this type of system. Because the water in the boiler is always the coolest water in the system and with the firebox of the boiler being surrounded with water, it makes a large amount of creosote; both in the boiler and worst yet, up the chimney. The way to eliminate some of the creosote is to use a mixing valve and circulator and maintain the water in the boiler at 175 F degrees.
http://www.newhorizonstore.com/Products/140-danfoss-vtc511-3-way-thermostatic-valve.aspx .
This is an example of a valve that can do this. A small generator to run the circulator in the event of a power failure is an alternative.

 

[Hobartian]

Hi AussieGeorge,

Check out my home made heater on this forum:
https://www.hearth.com/talk/threads...-based-on-the-design-by-richard-c-hill.68593/

I live in Hobart and I installed hydronic heating into three bedrooms, TV room and computer room. I also use the heater to heat the domestic hot water used in our home in winter.

My storage capacity is 1300 liters which is only just adequate. Double that capacity would be better.

A water temperature of above 70 C works best for hydronic radiators. Today I had the water in my storage tank at 99 C. Too high for safety. This is where a larger storage tank is safer as the rise in temperature in the tank is slower and the added heat storage means you can heat your home for a longer period without the boiler running. For instance I do not run my boiler when I retire for the night but by morning the water temperature will have dropped into the high fifties. I then burn another lot of wood to heat the water for the next nights operation.

You are welcome to come over to Hobart and have a look at my set-up. It certainly pays to get it right the first time and I feel it is better to have the capacity to store more heat than you need rather than having an under sized unit.

 

[AUSSIEGEORGE]

Thanks for the offer Hobartion, I will be in Tassy for work next month so I might take you up on the offer, i like your idea great to hear its working for you.

i have a few questions about the storage my plan was to use the boiler above without storage initially then once I have an understanding about how much heat we need pick the right size storage.
one thing i don't understand about storage is the water from the storage is used to pipe through the house is this water taken from a separate outlet in the tank? is this water then returned back through the boiler or just back into the tank? then i guess the water from the boiler is just continuously piped through the boiler and the tank through other inlet outlets right?

Also how are you heating you DHW coil exchanger in the tank or plate exchanger?

 

[Hobartian]

I think trying to use your boiler without any storage will be a hit or miss affair and I would not recommend it. You would lack control and have the danger of overheating and be an absolute slave to fueling the boiler when you need heating.

In my system I have separated the water that is in the storage tank from the water that is circulated through the radiators. I did this by using a plate heat exchanger and another circulating pump.
This separation of the water is not mandatory but for maintenance reasons it is better. Water is pumped from the top of the storage tank where it is the hottest through the exchanger and returns to a lower point in the storage tank. The storage tank water is heated by a very large heat exchanger which I fabricated and relies on a siphon action. I used two inch flexible pipes and there is no danger if there is a power failure.

I installed another plate exchanger inside my DHW tank as they are so efficient and take up very little space. Again this involves another circulating pump and wiring but in my case these components were already installed for my summer system which uses a reverse cycle refrigeration system.

 

[AUSSIEGEORGE]

interesting, you put the plate exchanger inside the tank or along side the tank?
Did you make or buy the storage tank? another fellow Aussie on this site has just purchased 4,000 litres of storgage he also imported an eco unit sounds cool but expensive.

from your exterience if it takes me 1 hour to heat 500 litres can you simply multiply this to estimate heating 4,000 litres for example 8 hours to heat 4,000?

I must say I truly enjoy this adventure of home heating with wood it must be a primal thing great to see others on this site with the same passion, why is Australia not as advanced in this type of heating, electricity and gas prices have alsways been high and will continue to get higher.

Do you buy wood? how much per ton of good hard wood in your next of the woods

Lastly have you tried or seen any one using plastic as a external storage?

 

[Hobartian]

interesting, you put the plate exchanger inside the tank or along side the tank?​

The heat exchanger is inside the tank together with two others which are used for water heating in summer and are connected to reverse cycle refrigeration units. Not good for servicing but good for efficiency.​

​

Did you make or buy the storage tank? another fellow Aussie on this site has just purchased 4,000 litres of storage he also imported an eco unit sounds cool but expensive.​

​

I made my own tank from mild steel. A big job which I probably wouldn't do again. A round tank is much stronger!​

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from your experience if it takes me 1 hour to heat 500 litres can you simply multiply this to estimate heating 4,000 litres for example 8 hours to heat 4,000?​

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My experience is zero concerning this question. The maths says it would be right.​

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I must say I truly enjoy this adventure of home heating with wood it must be a primal thing great to see others on this site with the same passion, why is Australia not as advanced in this type of heating, electricity and gas prices have always been high and will continue to get higher.​

​

​

Australia's climate is different to Europe. We tend to have cold nights where you need heating but our days generally warm up so there is not a constant need for heating. The other reason is cost! A hydronic system is expensive in Australia. The cost of the components is high and the installation costs even higher. I bought a lot of my components from English and American Ebay sites at below retail prices and installed them myself. The cost of oxy-acetylene gases and argon gas which I used when welding the tank cost me an arm and a leg. There has been a recent trend here in Tassie to install reverse cycle airconditioners for heating. Their cost is relative cheap now that they are being imported from China, however, with rising electricity prices I can envisage a decline in their use.​

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Do you buy wood? how much per ton of good hard wood in your next of the woods​

​

Fortunately I haven't needed to buy wood and generally scrounge timber from the bush. I own a small panel van and a couple of chainsaws. I don't know the price of timber per ton but I've seen trucks loaded with timber for sale for $350 (See my latest posting for the type of timber I can burn)​

​

Lastly have you tried or seen any one using plastic as a external storage? ​

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No, I haven't but one of the forum members specializes in making tanks from non-ferous materials. (Tom in maine) Corrosion is always a problem with steel and I have treated my tank water with a tannin product.​

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Looking forward to being warm!

If you want to be really warm move to Queensland. I lived there for over thirty years but I much prefer the weather in Tasmania.

 

[hobbyheater]

from your exterience if it takes me 1 hour to heat 500 litres can you simply multiply this to estimate heating 4,000 litres for example 8 hours to heat 4,000?
Lastly have you tried or seen any one using plastic as a external storage?

I have 1000 imperial gallons of storage, (an old steam boiler with its tubes removed). The Jetstream boiler is rated at 120,000 BTUs per hour and nets about 105,000 to storage. This gives a temperature rise of 10 degrees F per hour. Your math of 8 hours for 4,000 liters would be close.

When I put our system together 30 years ago, the water was plumbed direct to the dishwasher unmixed. Cleans dishes just great, but we go through a dishwasher about every 4 to 5 years as the plastic components just disintegrate from the 190 F water. The plastic storage tank may suffer the same fate.

 

[hobbyheater]

another fellow Aussie on this site has just purchased 4,000 litres of storgage he also imported an eco unit sounds cool but expensive.

The below pictures are of the section of insulated chimney that connects directly to the Jetsream. The outside view and inside view taken after burning 2 cords of wood. The gasification boilers do burn clean. The ECO boiler will burn half as much wood as a non-gasification boiler will. These boilers at first look expensive but once you have one, it's a purchase you would not regret.
I have also include the first page of the Jetsream manual. It explains the principals of clean burning.
A visit to see Hobartians set up would be worth while!