Another home brew boiler; gravity circuit. questions

[Dune]

Issue:
Work boat is often away from source of electricity and engine needs to be warm to start plus live aboard crew needs heat and cooking ability.

Problem;
existing diesel fired boiler consumes 2gallons/hr or about $200/Day.

Proposed solution;
I bought a Glenwood kitchen range.
Coal burner with a gas top for the summer.

Plan;
replace gas range with Glenwood and install Hilkoil to heat water.
Run engine coolant through Hilkoil
Thusly keeping engine hot.
Also run coolant through a 40 gallon Superstor for crew conveince (showers, dishes) .

Knowledge gap:
Gravity circulation.
What are the basics, the parameters, etc.

Engine and stove are at approximately the same height.

I can place the Superstor higher or lower.

I can put the expansion tank much higher if helpful.

Appreciate all input.

 

[velvetfoot]

Run engine coolant through Hilkoil
Thusly keeping engine hot.
Also run coolant through a 40 gallon Superstor for crew conveince (showers, dishes) .

I'm totally no expert, but should this coolant be non-toxic?

 

[pbvermont]

If its a true thermo-siphon hot water loop, the piping MUST rise (the more incline, the better) immediately after leaving the Hilkoil, all the way to the top of the Superstor. AND you MUST have a temp./press. relief valve right at the stove on the hot line going out. It is also desirable that the return line to the Hilkoil have a constant "fall" from the low point on the storage tank. Hot water is lighter than cold water. You should be prepared, ALWAYS for the temp./press. relief valve to blow off into a container. It will be blowing off engine coolant (ethylene glycol). If not an adequate thermo-siphon, you could consider circulating with a small DC circulator that operates off of battery and temperature sensor.

 

[Dune]

I'm totally no expert, but should this coolant be non-toxic?

We are not drinking the water so hopefully. Not.

 

[Dune]

If its a true thermo-siphon hot water loop, the piping MUST rise (the more incline, the better) immediately after leaving the Hilkoil, all the way to the top of the Superstor. AND you MUST have a temp./press. relief valve right at the stove on the hot line going out. It is also desirable that the return line to the Hilkoil have a constant "fall" from the low point on the storage tank. Hot water is lighter than cold water. You should be prepared, ALWAYS for the temp./press. relief valve to blow off into a container. It will be blowing off engine coolant (ethylene glycol). If not an adequate thermo-siphon, you could consider circulating with a small DC circulator that operates off of battery and temperature sensor.

So I should plumb the coolant into the engine from the return line after the Superstor.
I suppose then that it should enter the top of the engine and exit the bottom before returning to the Hilkoil and I will have to mount the (engine) expansion tank higher than the Superstor.

I pretty much HAVE to make it work without a circulator.

Sounds like I could plumb the relief valve into the engine expansion tank?

 

[pbvermont]

Best to post a drawing on here before there is any more discussion. Most of the systems discussed on this forum, do not involve ENGINES. This adds a very interesting wrinkle.

 

[Dune]

To clarify the last question could I plumb the outlet pipe from the pressure relief valve into the engine expansion tank?

 

[Dune]

Best to post a drawing on here before there is any more discussion. Most of the systems discussed on this forum, do not involve ENGINES. This adds a very interesting wrinkle.

I am on the boat and I dont think I have paint on my phone.
Think of the engine as a piece of heat in series with the Superstor.
I can upload a schematic tomorrow.

 

[Fred61]

Taking into consideration the amount of fuel oil your present system is consuming causes me to question if this set up is adequate. I've had past experience with the Hilkoil and wasn't that impressed with the heat output. I assume you're talking about a massive engine. Judging from the amount of time it takes to raise the temperature of my 450 Mercedes engine in my RV with 1500 watts, I'm questioning whether the Hilkoil is up to the job. It will only absorb a small percentage of the output of the stove and may overheat the area surrounding the stove.

 

[pbvermont]

"To clarify the last question could I plumb the outlet pipe from the pressure relief valve into the engine expansion tank?"

So….this question gives me great concern. You REALLY need to post a schematic. No further discussion should proceed until that has been posted. Most of the systems discussed on this forum don't involve engines or BOATS. You can draw a schematic on a piece of paper and take a picture with an Iphone and then post it, if possible. In this circumstance, using words only will not suffice.

 

[Dune]

Taking into consideration the amount of fuel oil your present system is consuming causes me to question if this set up is adequate. I've had past experience with the Hilkoil and wasn't that impressed with the heat output. I assume you're talking about a massive engine. Judging from the amount of time it takes to raise the temperature of my 450 Mercedes engine in my RV with 1500 watts, I'm questioning whether the Hilkoil is up to the job. It will only absorb a small percentage of the output of the stove and may overheat the area surrounding the stove.

I dont use the installed system.
It was meant. To heat the engine room and wheel house in Nova Scotia. I would be bankrupt the first week I tried to use it.
Last two winters I was in a marina so I used an electric block heater.
This year there is no product within range of the marina and I have to keep the boat on a mooring.
I only have to get the block temp up to 40F to start though warmer would be better.
Heat loss is sufficient in stove area.

 

[Dune]

O

"To clarify the last question could I plumb the outlet pipe from the pressure relief valve into the engine expansion tank?"

So….this question gives me great concern. You REALLY need to post a schematic. No further discussion should proceed until that has been posted. Most of the systems discussed on this forum don't involve engines or BOATS. You can draw a schematic on a piece of paper and take a picture with an Iphone and then post it, if possible. In this circumstance, using words only will not suffice.

Ok give me a few minutes

 

[Dune]

 

[Bob Rohr]

You could use a PG propylene glycol based engine coolant also, less toxicity. Preston Sierra is a Low-Tox engine antifreeze, probably other brands available also.

 

[pbvermont]

Thanks. That helps a lot. The main circulation loop looks like it will thermosiphon. Make sure you understand plumbing-in T.P. relief valves. It would be good to have one immediately behind the stove on the "hot" out line, and the other one high on the system at the exp. tank, and/or yet another, high on the Superstor. I don't understand your black line, plumbing CONNECTION between the exp. tank and the lower T.P. relief (??). Also, is your exp. tank a CLOSED w/bladder-type, or OPEN to atmosphere? Looks as if it may be OPEN. How about a check valve or "heat trap" on the stove "return" line to prevent backwards flow on start-up of stove. Do not let your ash-bed build up too high to cover your Hilkoil in the firebox. It is tricky to think about running ethylene glycol in a potable water system. You are not supposed to (in case of fluid systems ever mixing). It should be propylene glycol, but I'm not sure that works in an engine. You've got a strange "kettle of fish" going here.

 

[Dune]

Thanks. That helps a lot. The main circulation loop looks like it will thermosiphon. Make sure you understand plumbing-in T.P. relief valves. It would be good to have one immediately behind the stove on the "hot" out line, and the other one high on the system at the exp. tank, and/or yet another, high on the Superstor. I don't understand your black line, plumbing CONNECTION between the exp. tank and the lower T.P. relief (??). Also, is your exp. tank a CLOSED w/bladder-type, or OPEN to atmosphere? Looks as if it may be OPEN. How about a check valve or "heat trap" on the stove "return" line to prevent backwards flow on start-up of stove. Do not let your ash-bed build up too high to cover your Hilkoil in the firebox. It is tricky to think about running ethylene glycol in a potable water system. You are not supposed to (in case of fluid systems ever mixing). It should be propylene glycol, but I'm not sure that works in an engine. You've got a strange "kettle of fish" going here.

It isnt potable water.
The black line is the vent from the temperature- pressure relief valve.
The expansion tank is open.

One of my questions is whether it is ok to vent the TP into the expansion tank so I dont lose coolant in a blow off.

 

[Dune]

In this type of stove there are indirect flue passages to heat the baking oven.
I intend to mount the Hilkoill in the exhaust.stream rather than the fire box
but fly ash will still be an issue so thanks for mentioning that.

Damn is it blowing today. Nasty out here.

 

[Dune]

The check valve is another good point
Thanks

 

[Paso]

Dune the only thing I would add ( to the suggestions ) is as mentioned earlier is a small DC circulation pump that would really compliment what your doing. Also built something to direct the exhaust gasses to capture that heat as well. The pump could be switched or automatic in your application.

 

[Dune]

Dune the only thing I would add ( to the suggestions ) is as mentioned earlier is a small DC circulation pump that would really compliment what your doing. Also built something to direct the exhaust gasses to capture that heat as well. The pump could be switched or automatic in your application.

The entire enterprise is derived from the issue of zero electricity.
The system must run on gravity or it will be useless.

In fact it I could coach a few amps out of the stove too I would solve one of my largest life goals; self sufficient through solid fuels.

This case is so unique that it clearly warrents the use of TEGs which will be installed as budget allows but even then the electricity will only be for running computers and charging phones.

The power issue such a problem that I am building a vertical axis windmill to run the security system.
The beauty of the windmill is that if we aren't using the boat it is because it is too windy.

 

[Dune]

Also built something to direct the exhaust gasses to capture the heat.

This is a great suggestion.
I was grappling with the problem of running the exhaust through wheel house but instead I wil run it through the engine room in a finned copper pipe.

 

[Dune]

You could use a PG propylene glycol based engine coolant also, less toxicity. Preston Sierra is a Low-Tox engine antifreeze, probably other brands available also.

I will certainly take this suggestion if Cummins aproves.

 

[maple1]

If there is no electricity at all, how do you start the engine?

 

[pbvermont]

To be clear: this is a non-pressurized OPEN (to atmosphere) heating loop with some kind of glycol that takes a pass through a diesel engine block. What happens when the Superstor is full of btus, the stove is going, and so is the engine? You need to think through ALL scenarios of use and provide WELL for overheat. In a way, it's good that the system is OPEN. And technically, the useable water in the Superstor IS potable-- "for crew convenience (showers, dishes)".
Yesterday, it was very cold here (single digits F), I started my elderly diesel tractor with 5 min. of an electric heat gun (propane torch would also work) in the intake manifold, and a small "sniff" of ether in the air cleaner. Off she went.

 

[pbvermont]

the Hilkoil won't really perform too well outside of the firebox.