Geothermal Energy
1) Geothermal energy may come from :
- Volcanic areas
- Hot springs
2) Origin :
- Nuclear processes in Earth core (approximatively 100 000 m in depth)
- Ground temperature from solar radiation ( 10-20m depth)
3) How geothermal energy is extracted?
- Ground source heat pump
- Heat transfer
4) What is the difference between Passive and Active systems:
- Passive: Continues to work once installed
- Active: Requires energy impact to access ( pumps,..)
5) Some issues related to geothermal energy :
- Competition for limited water sources.
- Social, environmental, economic impacts
- Large space requirements for example horizontal systems
- Expensive equipment requirement ( vertical systems)
What is a heat pump ?
GHEX : Ground source Heat Exchanger
Here are some considerations we should evaluate before the design :
1) Consideration
- The energy needed: 10 kW per household => heat exchange rate of condenser, etc…
- The materials: the soil has a low thermal conductivity which is a limiting factor
Non-metal pipe (+ corrosion resistance)
- The configuration: horizontal or vertical
2) Design
1- Calculate the heating transfer needed to find the pipe area.
2- Define the surface area required: Pipe diameter + Calculate the length.
3- Configuration.
4- Material selection.
3) Assess performance
- COP
- Second law analysis
