Low Tech Magazine on Compressed Air Storage: Difference between revisions
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*P. 54 of reference [8] [https://eprints.usq.edu.au/24651/1/Herriman_2013.pdf] shows only 5% efficiency of overall system was obtained, calculating the total wattage of output to the total wattage of input. This is about 10x less than a claimed 50% efficiency of air storage. What gives? | *P. 54 of reference [8] [https://eprints.usq.edu.au/24651/1/Herriman_2013.pdf] shows only 5% efficiency of overall system was obtained, calculating the total wattage of output to the total wattage of input. This is about 10x less than a claimed 50% efficiency of air storage. What gives? | ||
*P. 60 of Ref [8] states that tank cost would be $25k and overall $30k. | *P. 60 of Ref [8] states that tank cost would be $25k and overall $30k. | ||
*Summary: efficiency of small scale prototype was 5% using an off-shelf tool motor (3Whr of usable power extracted from a 65l tank at 8 bar). This translated to a 3kW system being 65k liters. However, this is no-where near the predicted 50% roundtrip efficiency? Thus, indicates that the 65k liter figure is off by a factor of 10 for real, easily achievable results? Why was the efficiency so particularly low here? | |||
Revision as of 21:22, 1 April 2020
Article
- Low Tech Magazine article - [1]
Notes
- 40-50% efficiency of air storage, compared to 70-90% for batteries.
- Pumping and air engines are 60-70% efficient.
- Scroll Compressor is nearly 100% efficient, but expensive.
- Highest ESOI of any energy source - [2]
- Conclusion of Reference [7] - The sizing of storage tanks for a SHS-CAES has been determine by modeling all the components downstream of the storage tank. To operate the system with SHS load of 29.65W for 12 hours requires a tank size of 18 m3, with an initial pressure of 8 bar and regulator setting 3.511 bar.
- 8 bar system operates at around 60% roundtrip efficiency - that is impressive.
- P. 60 of thesis [3] shows the size of tank required for 3kWhr storage - 65 cubic meter.
- P. 54 of reference [8] [4] shows only 5% efficiency of overall system was obtained, calculating the total wattage of output to the total wattage of input. This is about 10x less than a claimed 50% efficiency of air storage. What gives?
- P. 60 of Ref [8] states that tank cost would be $25k and overall $30k.
- Summary: efficiency of small scale prototype was 5% using an off-shelf tool motor (3Whr of usable power extracted from a 65l tank at 8 bar). This translated to a 3kW system being 65k liters. However, this is no-where near the predicted 50% roundtrip efficiency? Thus, indicates that the 65k liter figure is off by a factor of 10 for real, easily achievable results? Why was the efficiency so particularly low here?