20150429 andy allen
TRANSCRIPT
Progress on Defining EnvironmentalSustainability
Andrew AllenDarren Robinson
Yong MaoThe Lucas group
Overview
1
• Mass / Energy Balance• The coal / human cycle • Entropy Balance• Application of Entropy Pumps• Local Sustainability• Internal Entropy production to land area relation• Moving away from “local” sustainability
Energy Balance
• Rate of Energy in = Rate of Energy out• Total energy in the system remains constant
4
Energy Conversion/Conservation
• Thermal Energy Increase = Electrical Energy Decrease• Note: TOTAL ENERGY CONSERVED
7Total Energy
Coal/human cycle
Sun: Energy Source
Space: Energy Sink
8
Combustion Combustion
Coal Coal
Carbon in atmosphere
TreesTree solar panel
Coal/human cycle
Sun: Energy Source
Space: Energy Sink
9
Coal Coal
Combustion Combustion
Trees
Carbon in atmosphere
Tree solar panel
Local sustainability
14
• Energy flow exists attributable to the sun
a. Direct radiationb. Natural work
• Mass flows exist due to natural transport processes
Conditions for local sustainability
�̇�𝑖=�̇�𝑒
1) For all material flows
2) For elements which are not in natural transport processes.
3) Density of material at surface boundary (red):𝜌 ≈ 𝜌𝑟𝑒𝑓
15
Conditions for local sustainability
�̇�𝑖=�̇�𝑒
1) For all material flows
2) For elements which are not in natural transport processes.
3) Density of material at surface boundary (red):𝜌 ≈ 𝜌𝑟𝑒𝑓
15
Conditions for local sustainability
�̇�𝑖 �̇�𝑒
�̇�𝑖=�̇�𝑒
1) For all material flows
2) For elements which are not in natural transport processes.
16
Conditions for local sustainability
• Boundary Conditions are necessary but not sufficient conditions for sustainability
17
• Additionally some sustainable outcomes may not be desirablea. Constrain system
Internal Entropy Production
�̇�
�̇�
• Assuming an overly idealised steady state process
𝐴𝑆=𝑘𝑠 �̇� 𝑠+𝑘𝐷 �̇�𝐷
18
Conclusions
20
• Mass / Energy Balance• Must Be able to close mass cycles either artificially or through
natural cycles• Sustainable habitats must use renewable energy sources • Internal Entropy production is a measure of irreversibilies in our
system and there may be a link between internal entropy production and land area.
• May be possible to assign a minimum internal entropy production per capita ,for a given standard of living, in a given environment.
• Also covered what it means to move away from local sustainability