I've mulled over a few challenges that don't seem to be mentioned so far. In particular, for a plant of the proposed scale - Can you imagine the complexity of the Environmental Impact Assessment Study.
I have two particular concerns. One of them is heat.
The transition from gaseous to liquid state is going to require the removal of a lot of energy in the form of heat - which has to go somewhere.
Where is this energy going to go?
The energy involved isn't trivial. Take a look at this table on the properties of saturated steam.
At atmospheric pressure (0 bar g, absolute 1 bar ) water boils at 100 oC and 417.51 kJ of energy is required to heat 1 kg of water from 0 oC to evaporating temperature 100 oC.
Another 2257.92 kJ of energy is required to evaporate 1 kg of water at 100 oC into 1 kg of steam at 100 oC.
Reversing this process means extracting all this energy.
Those little units I pointed to not only required a substantial injection of energy, it seems the heat energy being generated is just being dumped into the atmosphere. Not an option on a plant of the proposed scale methinks.
My second concern is that had the plant not extracted the water vapour, where would that water vapour have ended up eventually? I assume precipitation somewhere... that is no longer going to occur.
A drop in the ocean on small scale plants. A totally different story if you're looking to generate enough water to significantly impact a nation's gross agricultural output!
I have two particular concerns. One of them is heat.
The transition from gaseous to liquid state is going to require the removal of a lot of energy in the form of heat - which has to go somewhere.
Where is this energy going to go?
The energy involved isn't trivial. Take a look at this table on the properties of saturated steam.
At atmospheric pressure (0 bar g, absolute 1 bar ) water boils at 100 oC and 417.51 kJ of energy is required to heat 1 kg of water from 0 oC to evaporating temperature 100 oC.
Another 2257.92 kJ of energy is required to evaporate 1 kg of water at 100 oC into 1 kg of steam at 100 oC.
Reversing this process means extracting all this energy.
Those little units I pointed to not only required a substantial injection of energy, it seems the heat energy being generated is just being dumped into the atmosphere. Not an option on a plant of the proposed scale methinks.
My second concern is that had the plant not extracted the water vapour, where would that water vapour have ended up eventually? I assume precipitation somewhere... that is no longer going to occur.
A drop in the ocean on small scale plants. A totally different story if you're looking to generate enough water to significantly impact a nation's gross agricultural output!
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