3. Energy servics and energy demand

Question 1

3.1 Energy functions/energy services.
1. Definition.
2. Hierarchy.
3. Specific energy use.

Answer 1

1. Result of human activity through use of energy satisfying a human need.
2. Heating an insurance office.
3. I.e. energy used to heat one square meter of home for one year.

Question 2

3.2 Energy use in buildings.
1. Heat losses of buildings 3.
2. Transmission through walls.
3. Degree days

Answer 2

1. Conduction, convection, radiation.
2. R = R1+R2 = 1/k1+1/k2 = d/lamda/+
   k tot = 1/R tot
3. Over or under a base temperatur.

Question 3

3.2a Energy use in buildigs. Space heating, heat supply.
1. Flue gass losses.
2. Air excess ratio
3. Condensing boilers. Extra.
4. Heat pumps.
5. Passive houses

Answer 3

1. Amount of flue gas and flue gas temperature.
2. Air air used compared to air needed for stoichiometric combution.
3. Condensing boilers extra heat exchange capacity.
4. Heat pumps COP cofficient of performance.
5. Passive houses xx

Question 4

3.3 Energy use in transport.
1. Driving force includes 4
2. Engine efficiency 2
3. Electric vehicles 4

Answer 4

1. Air resistance, rolling resistance, friction in transmission, accessories
2. Thermal efficiency - to move the pistons. Mechanical efficiency - to keep the engine running.
3. Hybrid electrical, plug/in hybrid, battery driven, fuel cell electric vehicle.