04_Final and Primary energy demand

Amount of energy required for heating, cooling, lighting etc.

Useful energy demand + plant technology (losses from generation, distribution, storage and transfer of heat) → Extension of the assessment limit towards building boundary

Final energy demand + entire upstream chain (losses from extraction, conversion and transport of the respective energy source) → Extension of the assessment limit towards the energy source

The Gebäudeenergiegesetz (GEG) sets requirements for the energy performance of buildings, the creation and use of energy performance certificates and the use of renewable energy in the heating of buildings.

Three target values for single buildings:

1. Primary energy (PE) demand (kWh/m²/a)

2. Transmission heat loss (W/m²)

3. Proportion of renewable energies

max. useable thermal energy from combustion without condensation of the water vapour in the exhaust gas

max. usable thermal energy from combustion with condensation of the water vapour in the exhaust gas → usage of latent heat

• Heat pumps raise the temperature of ambient heat to a usable level

• Common compressionheat pumps use electricity as operating energy

• Sorptionheat pumps use heat as operating energy (> 70 °C)

• Reversible heat pumps can be used for heating and cooling

Pro:

Constant supply, high efficiency, makes renewables accessible

Contra:

Consumes electricity (compression HP)

(Coefficient of Performance), measured in the lab at fixed conditions

(Seasonal COP): Like COP but for the whole heating

season → Evaluate performance in a real setting

(German: JAZ – Jahresarbeitszahl)

• FLAT PLATE COLLECTORS

• EVACUATED TUBE COLLECTORS

• UNGLAZED COLLECTORS

• AIR COLLECTORS