Has anyone successfully created a power generator using a hot water source?

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Discussion Overview

The discussion revolves around the feasibility of creating a power generator using a hot water source, specifically a 55-gallon drum of water maintained at approximately 120°F. Participants explore various methods and concepts related to thermodynamic cycles, potential working fluids, and the efficiency of such a system.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant proposes using a closed vessel with a solvent that boils around 100°F to generate vapor for spinning a turbine, likening it to a traditional steam generator.
  • Another participant notes that using vapor pressure would affect the boiling point of the working fluid under pressure.
  • A third participant identifies the proposed system as a Rankine Cycle and mentions that while water is a common working fluid, it is not the only option.
  • Concerns are raised about the low efficiency of the system due to the small temperature difference between the hot and cold sides, suggesting that insulation might be a better use of resources if heating costs are involved.
  • Some participants mention the potential of nanotechnology in energy generation, although skepticism about practical power output and the need for a cold sink is expressed.
  • A participant calculates the maximum theoretical efficiency of the proposed system at 10.4%, assuming stable temperature maintenance.
  • One participant inquires about the progress of the initial idea, asking if any prototype was built.

Areas of Agreement / Disagreement

Participants express a range of views on the feasibility and efficiency of the proposed power generation method, with no consensus reached on its practicality or effectiveness. Some participants are optimistic about the concept, while others raise significant concerns about efficiency and practicality.

Contextual Notes

Participants discuss various assumptions regarding temperature stability, efficiency calculations, and the nature of the working fluid, but these aspects remain unresolved and contingent on specific conditions.

Who May Find This Useful

Individuals interested in thermodynamics, renewable energy generation, and experimental engineering projects may find this discussion relevant.

dr1ce
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Hi fellow science fans!

Say I have this 55-gallon drum full of water kept at an approximate constant temperature of 120° that I want to create power from. The air temperature is about 60°

I'm thinking a possible way to do this would be to submerge a closed vessel full of a solvent that will boil at say +/- 100° and using the vapor from this solvent to spin a turbine, like a traditional steam generator. I would then like to use the ambient air temperature to condense the solvent back to a liquid for recycling.

I imagine someone has tried something like this at some point in history.

Is there a name for this sort of generator?

Any idea what sort of solvent would have the characteristics I'm talking about at these temperatures?

Also, I should mention, the hot water is free and I'm not trying to create "extra" energy from heating water or anything. Basically, pretend I'm using a hot spring the size of a 55 gallon barrel.
 
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Hi dr1ce! http://img96.imageshack.us/img96/5725/red5e5etimes5e5e45e5e25.gif

You plan to use the vapour's pressure? In which case, your working fluid will not boil until at a higher temperature while under pressure.

As an aside: this idea of an intermediate stage is used in nuclear power stations, but for a different reason: to put a stage of isolation between the fluid that circulates through the reactor (and which in the event of a problem could become radioactive) and the "outside world" of the steam turbine generators, so any outside leaks are of a hopefully uncontaminated fluid.
 
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Exactly the info I was looking for!

Much Thanks...
 
At this stage it may be worth while asking how much power you would be expecting. Is this a fun project 'to show it can be done' or a serious attempt to harvest some free energy? Your problem here is that the temperature difference is very small (on the thermodynamic scale) and that means very low efficiency.

What is the power source that keeps your drum at 120°(F?)?. If you are paying for the energy to do the heating then it doesn't make sense to try to use this warm water as an energy source. Better to insulate it and use the electricity you saved. But this may be a misplaced voice of reason and NO FUN AT ALL :rolleyes:

I have seen a number of model Stirling Engines, working with pretty small temperature differences. There are construction kits available for making them. They do little more than manage to turn their own mechanism but the do prove a point.
 
dr1ce said:
Hi fellow science fans!
Nanotechnology to the rescue. http://www.digitaltrends.com/mobile/power-felt-electricity-generating-fabric-could-one-day-power-iphone-with-body-heat/
 
NascentOxygen said:
Nanotechnology to the rescue. http://www.digitaltrends.com/mobile/power-felt-electricity-generating-fabric-could-one-day-power-iphone-with-body-heat/

No mention of actual power output from this device, of course. Whilst there is clearly some waste heat from your body, you still need a cold sink. What form would this take? A large radiator strapped to your back? How about on a sunny day?
I could be eating my words in a few years' time, I admit but, as my favourite song goes - "it's the numbers that count".
 
Based on the 120 degree hot-side temperature (I assume you mean fahrenheit), and the 60 degree cold-side temp, the maximum efficiency you can attain is 10.4%. That assumes you're able to maintain both teperatures fairly well.
 
Hi all! Just wondering what ever became of the idea. Did you ever build one?
 

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