A really crazy idea...

Blackoakbob

when I was at the last Wetstock in Minneapolis there was a guy there that had available "now" a gas driven generator and heating system with a 90+ furnace to use when the genset didn't provide enough heat or when cooling is needed. It was a nice little package that fit in the basement or garage. Maybe someone will remember the name for me. Best Regards.

Dirk Wright

A really crazy idea

I've been thinking long and hard about backup electrical power and I have this crazy idea of using a really small steam turbine to drive a generator. I suppose one could use a domestic oil fired boiler for the source of steam. Of course, providing the electricity for the boiler would be a problem. Dresser-Rand makes really small power steam turbines in the 20-40 hp range. I don't know what they cost, but I'm sure they aren't cheap. Maybe this is a way too complicated way to solve a non-existant problem? My electricity is very reliable, but when a storm hits, we can be out for a long time. Something for the steamheads to think about I suppose.

hr

Actually

There was a father and son team near Branson, Missouri building small steam/ electric systems. These were actually powered by a wood fired steam boiler that the son built, while his dad built the engines (not turbines)

I visited them once, he also had a small steam powered power boat on the lake!

They used a large 12 V truck altenator, as I recall, with and inverter to 120 volt. It could also recharge a battery bank and tie in with solar PV systems.

There was an article about this company in Backwoods Power mag a few years ago. I think the company was called Sensible Steam, something like that.

hot rod

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Tony Conner_2

The Technology...

...has been around for over 125 years. It works great. The only problem is the cost. You'll also need a high pressure steam boiler to drive a turbine or steam engine, and that pulls the whole installation under all kinds of codes. Pretty much the only way to have it come close to having a payback is to run it year round, and use the exhaust steam for heating. Even at that, there's big chunks of the year where there's no heating requirement. There are a few exceptions (mostly HUGE operations) where this can pay back. Free fuel really helps - or even better - one that people will pay you to take away like wood waste or garbage. Remember that solid fuel is labour intensive, and even if it's automated, it's a heavy maintenance area. Solid fuel also tends to pull you under a lot of emission/environmental regulations as well.

A better consideration, is likely a diesel generator, and pull the heat out of the exhaust. Again, though, you really need a home for the exhaust heat, to make it pay back.

I love stuff like this, but it's not very often you can even come close to having it make financial sense, unless you live in a REALLY remote area and/or one that has just brutal energy costs.

JimGPE_3

Electricity?

No problem. Just start the gen set 5 minutes before the power outage and you'll have way more power than you need to run the boiler controls.

Wait....

Tony Conner_2

You Can...

... get around "black start" issues pretty easily. Coal fired steam locomotives routinely did it. Newer more automated examples would be small diesel gen sets, or gas turbines that can be started to supply enough electricity to get much bigger steam plants rolling. It takes a while, but some of the plants with "black start" capabilities are HUGE.

It all comes down to how much can you justify spending? At it's simplest, it would be a locomotive or marine style set up, manually firing coal. That techology powered railways, ships and factories for 150 years.

GMcD

Or...

Just get some solar water panels, some solar photovoltaics and a geothermal heat pump, along with a storage tank and a battery bank and inverter, and stay off the grid in the first place. Why burn fossil fuel if you don't need to. Mom Nature provides a lot of free energy if we choose to use it.

Dirk Wright

Thanks for all your kind thoughts about this crazy idea. I did some reading, and the new "hot" idea is microturbines, which are small gas turbines that drive generators at high speed for 30 KW and up. The idea is a distributed power grid instead of the current centralized setup. Unfortunately, they don't have these small enough for home use yet, but they may be coming. The smallest that I could find is the Capstone, but it puts out 30 KW @ 3 phase power at 480 volts as I recall. Not very useful for home use. I've seen NOS ones for sale for about 16K$. The advantage is one moving part, no lubrication or cooling fluids required, and can run on propane, natural gas, diesel or other fuels. Electrical generation efficiency is about 27% I think, which isn't great, but they have very low exhaust emissions.

Aidan (UK)

microCHP

There are micro CHP sets under test in the UK; they may be on the market by now.

http://www.microgen.com/main2.swf

This one is a Stirling engine system, producing 1.1 kW electric & 15 kW of heat.

With oil fuel (gas oil), a diesel generator as Tony suggested would be by far the simplest arrangement. There is a factory near me running a surplus stand-by generator set on bio- diesel with a Fuelmeister set-up to process the vegetable oil fuel. The generator is not modified. The heat produced is wasted, at present.

Tundra

Micro CHP

The idea behind MicroCHP is to start the generator in the fall and run it continusly till spring. The idea is not to generate all your electricity but to generate a baseline, say 1Kw. You then pull the remainder from the grid. You take your waste heat , say 20,000BTU's and pump that into the house. You now have an energy efficiency in the mid 90* range. For maximum efficiency you only run it when you require both heat and electricity. There are companies in Europe, America and Australia atleast, working on this.

bob_50

Economics

In 1990 I worked on the installation of a Solar Turbines, Mars natural gas turbine. It's output is 8,800KW plus 40,000 lbs/hr of 225lb steam. It cost $12,000,000 to install and paid for it's self in less thsn three years. The company that owns it is the largest marketer of nat. gas in the USA, BP. The price of nat. gas has increased so much that it is now moth-balled. Hard to believe.

Tony Conner

Economics

I've worked with this stuff too. It's really hard to find an application where the gas turbine driven generators and related heat recovery boilers can hit a decent payback. You need an electrical & thermal load that match - both in terms of size, and WHEN they happen. If the peak electical demand is at 3 PM, but the peak thermal demand happened back at 7 AM, that's a problem. You wind up burning gas to drive the turbine gen set, but with not much thermal load, a lot of the hot exhaust just gets diverted up the stack, rather than through the heat recovery boiler. When the thermal peak for your plant hits, the electical demand isn't there, so you wind up having to fire conventional boilers to cover that load.

I witnessed some very impressive slight of hand involving spreadsheets - people just kept massaging numbers trying to show a payback. If somebody plays around long enough, they can make almost anything appear to make sense - on the screen. But when the results of "spreadsheet madness" collides head-on with reality, out in the real world, guess which one comes out on top? You don't need an MBA from a big business school to understand that if you're spending more money on fuel to drive your generator than you're getting paid for the electricity you're producing, that this is a BAD thing, and you should probably stop doing it.

Hydraulic (falling water), nuclear, and coal fired generating plants will bop along generating electricity at pretty much the same cost, regardless of the world price of oil (and by default, natural gas). They don't use oil or gas, so price fluctionations for those fuels have no particular impact on them.

Kal Row

yah gona condense dat shteem or vent it??...

need a hell of a condensor for lossless ops.. if you vent it, your neighbors might call the fire dpt

but it is a much quieter solution than a gas or diesel gen

Christian Egli

The home sized cogeneration set, heat, power and success

Noel Kelly was the name,

climate-energy.com was the company

Nice memory, Blackoakbob. By the way, did that boiler ever stop bouncing?

Fun at the Wetstock

Noel Kelly_3

Thanks Christian - nice to see that you were paying attention

Seriously, Tundra got it right above. The ideal is considered to be in the 1kW electric region to maximise run time. Climate Energy achieves this by delivering the associated 10,000 Btus of heat to the home constantly in response to outdoor temps.

And while this unit won't be commercially available until '06, we intend to site up to 30 systems this fall for the purpose of collecting operating data etc. The Climate Energy Micro-CHP is internet enabled and this will allow us to record multiple data points.

We had a great day at the GasNetworks conference and enjoyed meeting many on the industry's finest, some of whom asked about a hydronic version - this will happen next year.

I will keep you updated on developments as they occur with particular emphasis on the performance data from the upcoming heating season.

www.climate-energy.com


Noel

Dirk Wright

What you appear to need is a hybrid system, i.e., a large bank of batteries that are charged at 7 AM and discharged at 3 PM. This sure does get complicated fast!

Jason_15

Coal plants

How does train, after train, after train of coal get to the generating plant? by burning up diesel! Nuclear and hydroelectric would or should be much less affected.

Tony Conner_2

A lot of coal plants are on navigable waterways, so fuel can be delivered by ship or barge - the same as oil. Every fuel has mining and/or refining and/or transportation costs, except for hydroelectric, which floods a zillion acres behind the dams. I'm not sure that that's an advantage.