Stirlingengineforum.com

Hi All,
First post. Recently discovered Stirling Engines so excuse my ignorance. What is stopping Stirling engines from becoming widely used in the Geothermal field. Is it cost for large installations? Efficiency would not seem to be a major issue if the heat source is free and, practically inexhaustible. Here's an example from New Zealand where I live, https://www.renewable-technology.com/pr ... ower-plant This plant produces waste heat at 350degC and uses recycled river water as coolant after the turbine. Instead of simply raising the temperature of the atmosphere, why are Sterling Engines not used to achieve the same effects and increase power output? eg a series of S.E.'s extracting heat until "break even" point. Hope for some answers from the knowledgeable.

What is stopping Stirling engines from becoming widely used in the Geothermal field.

What is stopping Stirling engines from becoming widely used.
Nothing is stopping it, if build right they are very efficent. All whats needed is a commercial product at the right price.

The lure of "free" energy is ever present. It would be great to get more energy out of a plant using it's free waste heat. Let us do some calculations.

Carnot efficiency: n = 1-Tc/Th = 1-(273.15 +30)/(273.15+350) = about 0.54

River heat rejection assumed to be at 30 C.

That is about %54. The actual efficiency will be much less, possibly as high as 20 or 30 percent. So over 60 percent of the heat will still go into the river. Not the sole reason for using a Stirling. The rest, as pointed out above, is the start up and operating/maintenance costs, compared with the selling price of electricity. There is also, can't sell an engine cheap enough until someone is mass producing them. Aren't going to mass produce them until people are buying lots of them. The materials for making Stirlings are expensive, not as expensive as the were. The lure, of higher efficiency than an IC engine, is ever fleeting and ever tempting. Thank you.