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Heating. Martinás Katalin ELTE, Atomfizikai Tanszék. Exergy and Industrial Ecology. Case study – District heating. District Heating and Cooling ? Market Failor. EU – good – the future Or Hungary – uneconomic – the past MARKET FORCES TO LEAVE THE DH SYSTEM. HEAT PUMP 1,5 WOOD 2,5
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Heating Martinás Katalin ELTE, Atomfizikai Tanszék
Exergy and Industrial Ecology • Case study – District heating
District Heating and Cooling?Market Failor • EU – good – the future Or • Hungary – uneconomic – the past • MARKET FORCES TO LEAVE THE DH SYSTEM
HEAT PUMP 1,5 WOOD 2,5 COAL 3,1 GAS 3,6 DH 4,5 ELECTRIC 6,0 PB-GAS 7,1 Prices Ft/MJ
The four laws of thermodynamics • 0. Bodies in contact with each other assume the same temperature. • 1. energy conservation • 2. Any transformation leads to losses • 3. When the temperature of a system is zero (K) entropy reaches a constant value.
Heat pump • 1 GJ heat • -3 C environment • 27 C room 1* 30/300 = 0,1 GJ electric energy
Exergy • Exergy is a term that is used to show the maximum work a system can produce
Exergy • All the differences: • B = (T-To)S – (p -po)V +… • Thermal part • B = Q (T – To)/T
Laws of Nature • Exergy – no production • Every transformation leads to losses
Exergy of heating1 GJ Heat Inside outside B temperature temperature 20 20 0 20 10 0,03 20 0 0,06 20 -10 0,1
Exergy of with gas heating1 GJ Heat Inside outside Exergy temperature temperature loss 20 10 0,97 20 0 0,94 20 -10 0,9
Solution - cogeneration All energy end up as heat
Cogeneration • Present practice • 50% less fuel for heating
Exergy price comparision PRICE Exergy Ex-price • Ft/MJMJ/MJ Ft/MJ • HEAT PUMP 1,5 0,9 1,7 • WOOD 2,5 1,7 1,5 • COAL 3,1 1,4 2,3 • GAS 3,6 1,2 2,6 • DH 4,5 0,6 7,5 • ELECTRIC 6,0 3,0 2,0 • PB-GAS 7,1 1,2 5,1
Advantage of DH • Can utilize energy with low value (exergy) - utilize loses from many other processes (CHP, waste incineration) • Easy to change fuel – few units • Easy flue gas cleaning – few units • Big share of cost are investment cost – steady prices, money stay in the local community
Hungary • Főtáv Zrt – 2007- 12 Md GJ • 4500 Ft/GJ Energy – from gas – 8,5 Md Ft from PP – 23,8 Md Ft electricity- 1,3 Md Ft wages 2,2 Md Ft other 17,8 Md Ft
Győrhő Zrt- • 2790 Ft/GJ • In Győr DH is cheaper than the gas heating.