Energy Resources - Conservation Flashcards
How can energy conservation be described?
- Using less energy to perform the same function (efficiency)
- Reducing wasted energy
How does heat recovery work in an industrial setting?
- Industrial waste (L/G) is often hot but toxic
- Cold, clean L/G can be fed into a heat exchanger and heat energy from the waste is transferred to the new L/G
What is the most important part of heat recovery?
The two substances do not mix
How can a heat exchanger be designed?
- Long thin pipes for high SA:V
- Made of conductive material such as copper
How does insulation work in an industrial setting?
- Heat loss can be reduced by using an outer layer with low thermal conductivity
- Plastics and textiles
How does high volume storage work in an industrial setting?
- Hot industrial fluids should be stored in tanks at the highest possible volume
- Reduced SA:V retains heat energy for longer as there are less surfaces for heat transfer
What are the optimal shapes for industrial HVS?
- Sphere
- Cylinder (more practical)
How does combined heat and power (CHP) work in an industrial setting?
- Most power stations only have a 40% efficiency as 60% of energy is lost as heat
- CHP utilises this heat for domestic uses such as space heating
What can happen if CHP water is contaminated?
Heat recovery
How does integrated manufacture work in an industrial setting?
- Manufacturing processes occur in the same location
- Prevents steel from being solidified and melted again
- Reduced energy needed for transport of materials
How does industrial recycling work?
- Requires less transport and energy
- Cheaper than manufacturing virgin materials
- Recycling an Al can uses 5% of the energy it take to manufacture one from virgin Al
What are examples of electricity infrastructure management?
- Peak shaving
- High voltage grid
- IT management
- Location of generation
What are two easy ways to conserve energy in transport?
Bulk transport of goods and passengers
How can air resistance impact energy conservation?
- Vehicle aerodynamics and hydrodynamics
- Improved flow of air/water over the vehicle reduces resistance
- Aerodynamic fairings on cabs
How can regenerative braking impact energy conservation?
- Ek of wheels is captured and fed to a battery
- Reduces energy lost as heat due to friction during braking
- Uses an electric motor
How can vehicle weight impact energy conservation?
- Reduced mass leads to a reduced energy requirement to propel a vehicle
- Lighweight materials where strength isn’t important (plastics)
- Steel alloys rather than steel
- Higher energy density batteries
How can wheel design impact energy conservation?
- Pneumatic tyres on road vehicles lose heat due to friction
- Solid wheels lose less energy and can be used by trains/trams
How can fuel combustion impact energy conservation?
- Efficiency of combustion can be improved
- Efficient removal of exhaust gas
- Improve engine temp control
- Ignition control
- Regular engine servicing
What is a vehicle’s optimum speed?
The speed at which the largest distance is travelled using the smallest amount of fuel (around 56 mph)
What is end of life design in transport?
- Vehicles built with components which are easily identifiable and can be deconstructed
- Compostable carpets and seat materials (natural fibres)
What is embodied energy in transport?
- The energy used to produce a vehicle
- Equal to 1.5 years of fuel consumption for an average car
How can embodied energy be decreased?
- Recycling
- Renewable energy use
What are examples of infrastructure and traffic management?
- Smart motorways to reduce congestion (open and close lanes as required)
- Variable speed limits to moderate traffic flow
- Driverless cars can be programmed to maximise energy efficiency
How can building design impact domestic energy conservation?
- Orientation (PSA)
- Shape and surface area (PSA)
- High thermal mass materials
What are examples of high thermal mass materials?
- Stone
- Bricks
- Concrete
Which materials have high embodied energy?
- Concrete
- Metal
Which materials have low embodied energy?
- Timber
- Limecrete (instead of concrete - lime as a binder)
- Lime mortar (instead of cement mortar)
- Rammed earth (for walls)
How do earth sheltered buildings conserve energy?
- Earth is hotter than the air at the surface
- Part of the building sunk into the ground
- No air above to remove heat and increase temp gradient
What 4 factors affect heat loss from buildings?
- SA:V
- Temp gradient
- Loss of air from inside
- Wind or wind chill
How can heat loss be reduced?
- Reduction of convection (double glazing)
- Reduced radiation losses
- Reduced loss of warm air (draught proofing)
What are examples of improved insulating materials?
Low environmental impact
- Wool
- Paper
- Straw
Which gases can be used in window cavities?
- Air
- Argon
- Krypton
- Xenon
What is a U value in window glazing?
- W / m2 C
- The rate of heat transfer through a building component such as a window
What does a U value assess?
- Thermal performance
- Low U value = low rate of heat loss
What is low-e glass?
- Low emissivity glass
- Surface coating reflects long wavelength infrared energy back into the building
How does heat recovery ventilation work?
- Heat exchangers used for ventilation
- Heated air leaving a building transfers energy to the air entering
How does automatic ventilation work?
- Large glazed areas receive passive solar gains in summer which may be excessive
- Over-heating can be reduced by using thermostatically operated automatic screens
What are examples of automatic ventilation?
- Self-opening windows
- Solar screens
How does an occupancy sensor work?
- Detects sources of infrared or movement
- Turns appliances off when no occupants are detected
How do programmable thermostats work?
- Adjusts heating in a large number of rooms
- Reduces energy wasted from unnecessary heating
How does water heating conservation work?
- Water should be heated as its supplied or soon before
- Hot water stored in insulated tanks
- Reduced hot water use (showers, water efficient appliances, eco programmes)
What system does the UK have for appliance efficiency?
Energy rating scale
- A = high efficiency
- D = low efficiency
What are examples of lower energy appliances?
- LED lightbulbs (instead of CFL)
- Low energy washing machines
- Plasma and LED TVs
- Glazing on cooker doors
How can human behaviour reduce domestic energy use?
- Turn lights off when not required
- Turn thermostats down
- Turn appliance off rather than standby
