Post by dominik on Jan 18, 2019 10:28:49 GMT -5
Hello together,
during test phase of my last gas generator it turned out that it was much too big for the use as a household heat and power plant,
it´ll be further used for fun, but that´s another story...
For the new project I need some input and check from you.
Economical surroundings (can be skipped):
The plant will be controlled by the need of heat and the power generation will be the plus. Reason for this is, that the costs for power
have increased here by 20% in the last years and the actual political situation is continuously pointing further in this direction.
At the moment, just as a an example, the price of heating oil and electricity are related in such a ratio that if you would produce electricity
of fuel oil and leave all produced heat unused (not allowed!), you would "just" need an efficiency of 28%. This is indeed very high
efficiency for a small plant but here we want to use as much heat as possible and just take the power as a bonus.
So 28% efficiency is not the target.
Technical ideas:
The target is a power production of 1,2 to 3 kw and a heat production of ~16kw. Efficiency of the power stage related to the fuel burned
is targeted at 7% to 16%. These values are perfect for the cold period and related to the actual use I have at home.
(For the summer I plan to add solar panels later)
The options for the desired plant were given with: using a small diesel engine or using a small turbine.
I quit with the diesel very fast because of vibration, pollution and maintenance. If the last will stay true
with a turbine operated for long periods will be seen later, however a new CHRA is not that expensive
and this is even more true for the chosen and already delivered Hitachi HT18.
It was my choice because of price and connection/mounting options:
Here are some neutral pics:
The wastegate will be disabled and removed later.
I dissembled the housing and checked the turbine and compressor wheel diameters:
The compressor wheels inducer is 42mm and the turbine wheels exducer is 44mm.
Searching for a compressor map turned out to be difficult, a similar
sized one is the Mitsubishi TD04H, here is the map:
The waste gate aftermarket replacements fire at 1.7 bar, this is also the top of this map.
Does anyone have a HT18 map or knows if it´s similar to the TD04H?
I plan to use windmill starting (leaf blower method) with a fixed fan. The Fan pressure
will close some reed valves that can be pulled open by low pressure later, after turbine has started.
The fan I plan to use is rated at 800W max., but can be replaced by a larger one if necessary.
One problem is, that I want to start on oil and do not want to add a linear valve, I would
prefer to have two nozzles controlled by simple magnetic on/off valves, nozzles are driven
by a commen oil burner pump at 7bar (100psi). Now I wonder how to choose those:
Given the power estimations above, I would need one 0.5 gph nozzle, this nozzle can
be splitted into two 0.25 gph, resulting in fuel flows of 0 / 0.25 / 0.5 gph.
In this case the original valve from the pump can be used.
Maybe better to use one 0.25 and one 0.5 with separate valves to be able to flow 0 / 0.25 / 0.5 / 0.75 gph.
I was too lazy checking the math until now: So the major questions are:
Is a flow of 0.25 low enough for a smooth start and 0.5 high enough
to keep it above idle? Any ideas on that?
My first step will be the design of a combustion chamber. This time it´ll be three walled +
isolation by having water in the outer section to also collect that heat. Therefore it´ll be a little
bit more of work and I would like to have a direct hit, so I used the JetSpecs software this
time and it gave me a length of 252mm with a diameter of 126mm (10 by 5 inches).
This seems quite bulky and in respect to the planned ignition method I would say it must be
longer, and I would prefer it to be smaller... any tips on that?
The turbocharger has a water cooling option, it should be used also for heat collection and the water
temperature will stay below 80°C. Is it a good idea to use the heating oil for the journal bearing
to be preheated and as a lubricant or will this result in a poor lifetime? The fuel oil is quite thin and
would make starting a lot easier then (Not to mention that it will be replaced constantly and I need
no separate oil circuit, pump, etc..)
Sorry for that long post, but any help is welcome.
(The ideas on the free power stage, power generation and storage will be added after the turbine is working)
Regards
Dominik
during test phase of my last gas generator it turned out that it was much too big for the use as a household heat and power plant,
it´ll be further used for fun, but that´s another story...
For the new project I need some input and check from you.
Economical surroundings (can be skipped):
The plant will be controlled by the need of heat and the power generation will be the plus. Reason for this is, that the costs for power
have increased here by 20% in the last years and the actual political situation is continuously pointing further in this direction.
At the moment, just as a an example, the price of heating oil and electricity are related in such a ratio that if you would produce electricity
of fuel oil and leave all produced heat unused (not allowed!), you would "just" need an efficiency of 28%. This is indeed very high
efficiency for a small plant but here we want to use as much heat as possible and just take the power as a bonus.
So 28% efficiency is not the target.
Technical ideas:
The target is a power production of 1,2 to 3 kw and a heat production of ~16kw. Efficiency of the power stage related to the fuel burned
is targeted at 7% to 16%. These values are perfect for the cold period and related to the actual use I have at home.
(For the summer I plan to add solar panels later)
The options for the desired plant were given with: using a small diesel engine or using a small turbine.
I quit with the diesel very fast because of vibration, pollution and maintenance. If the last will stay true
with a turbine operated for long periods will be seen later, however a new CHRA is not that expensive
and this is even more true for the chosen and already delivered Hitachi HT18.
It was my choice because of price and connection/mounting options:
Here are some neutral pics:
The wastegate will be disabled and removed later.
I dissembled the housing and checked the turbine and compressor wheel diameters:
The compressor wheels inducer is 42mm and the turbine wheels exducer is 44mm.
Searching for a compressor map turned out to be difficult, a similar
sized one is the Mitsubishi TD04H, here is the map:
The waste gate aftermarket replacements fire at 1.7 bar, this is also the top of this map.
Does anyone have a HT18 map or knows if it´s similar to the TD04H?
I plan to use windmill starting (leaf blower method) with a fixed fan. The Fan pressure
will close some reed valves that can be pulled open by low pressure later, after turbine has started.
The fan I plan to use is rated at 800W max., but can be replaced by a larger one if necessary.
One problem is, that I want to start on oil and do not want to add a linear valve, I would
prefer to have two nozzles controlled by simple magnetic on/off valves, nozzles are driven
by a commen oil burner pump at 7bar (100psi). Now I wonder how to choose those:
Given the power estimations above, I would need one 0.5 gph nozzle, this nozzle can
be splitted into two 0.25 gph, resulting in fuel flows of 0 / 0.25 / 0.5 gph.
In this case the original valve from the pump can be used.
Maybe better to use one 0.25 and one 0.5 with separate valves to be able to flow 0 / 0.25 / 0.5 / 0.75 gph.
I was too lazy checking the math until now: So the major questions are:
Is a flow of 0.25 low enough for a smooth start and 0.5 high enough
to keep it above idle? Any ideas on that?
My first step will be the design of a combustion chamber. This time it´ll be three walled +
isolation by having water in the outer section to also collect that heat. Therefore it´ll be a little
bit more of work and I would like to have a direct hit, so I used the JetSpecs software this
time and it gave me a length of 252mm with a diameter of 126mm (10 by 5 inches).
This seems quite bulky and in respect to the planned ignition method I would say it must be
longer, and I would prefer it to be smaller... any tips on that?
The turbocharger has a water cooling option, it should be used also for heat collection and the water
temperature will stay below 80°C. Is it a good idea to use the heating oil for the journal bearing
to be preheated and as a lubricant or will this result in a poor lifetime? The fuel oil is quite thin and
would make starting a lot easier then (Not to mention that it will be replaced constantly and I need
no separate oil circuit, pump, etc..)
Sorry for that long post, but any help is welcome.
(The ideas on the free power stage, power generation and storage will be added after the turbine is working)
Regards
Dominik
"