AWARD FOR THE BEST ENERGY EFFECTIVE PROJECT 2008 in Slovenia

1. AWARD FOR THE BEST ENERGY EFFECTIVE PROJECT 2008 in Slovenia Optimal use of renewable energy sources for heating and cooling of our office building

2. Goals of the project: • to build business areas for the company • to build energy effective building, taking into account modern design of the building and contemporary systems of cooling and heating • use of renewable energy sources • use of up-to-date materials at construction • to limit the power of Gas-fired boiler under 50kW because of the lower expenses of construction for mechanicalroom, maintenance and operation • to build a reference building for the purpose of promotion of renewable energy sources and efficient use of energy • employee friendly work environment

3. 3 years ago:

4. Today:

5. Design of the building • Reinforced concrete skeleton with a structural glass façade • Glass surfaces with coloured glazing • Use of renewable energy sources and efficient use of energy • Effective ventilation with recuperation • Concrete core heating • Heat-insulated parapets • Use of glassfoam - Technopor for insulation • Exterior shading

7. Heating and cooling scheme • Legend • Ground probe • Heat pump (Brine/Water) • Hot water storage cylinder • Cold water storage cylinder • Sanitary water cylinder • Gas-fired condensing boiler • Air conditioning device • Radiators • Floor heating • Convectors • Temperation of concrete mass

8. Heating of the building Heating with heat pump. Support to the heating with Gas-fired condensing boiler. Air temperation and ventilation with air conditioning with recuperation up to 80%. Accumulation in concrete core.

9. Cooling of the building Cooling with heat pump. Air temperation and ventilation with air-conditioning with recuperation up to 75%. Accumulation in concrete core.

10. Passive cooling Passive cooling directly from ground probe. Operation of circulation pumps. Alternation through air conditioning device. Recuperation according to the difference between the outdoor and indoor temperature. Accumulation of cool energy in concrete core.

11. Investment & costs Energ. eff. construction Trad. construction • Investment for heating & cooling 134.000 € 134.000 € • Gas boiler house with equipment 14.800 € • Ground probe with equipment   52.957 €     • Together 186.957 € 148.800 € • Difference in the investment 38.157 € • Heat loss from the building 105.076 kWh 112.276 kWh • Use of gas for heating 11.856 Sm3 • Heat gain of the building 28.039 kWh 36.451 kWh • Use of electricity for cooling (έ = 2,6) 14.020 kWh

12. Savings and investment return period Heating – winter 2006/07 Heat pump, Gas-fired condensing boiler • Yearly use of heating energy according to the calculation 105.076 kWh Actual measured values • Use of primary energy sources for heating 34.820 kWh 2.850 € • Gained heating energy 92.630 kWh • Used energy and gained energy ratio 2,66 • Savings at energy effective construction 77.456 kWh 4.049 € Cooling - summer 2007 Heat pump, passive cooling • Yearly use of cooling energy according to calculation 28.039 kWh Actual measured values • Use of primary energy sources for heating 1.892 kWh 178 € • Gained cooling energy 12.450 kWh • Used energy and gained energy ratio 6,58 • Savings at energy effective construction 12.128 kWh 1.140 € Savings - season 2006/07 89.584 kWh 5.189 € Investment return period 7,35 year

13. Specific use of energy Heating • Specific use of the old building   151,0 kWh/m2 • Specific use of the new building without renew.sour.82,1 kWh/m2 • Specific use of the new building with renew.sour. 26,7 kWh/m2 • Actual specific use of energy measured in 2007 33,0 kWh/m2 Cooling • Specific use of the old building No cooling • Specific use of the new building without renew.sour. 21,9 kWh/m2 • Specific use of the new building with renew.sour. 3,35 kWh/m2 • Actual specific use of energy measured in 2007 1,48 kWh/m2

14. Conclusion • For heating, cooling and ventilation we need only 1/3 of primary energy sources compared to conventional heating and cooling system. • Loss of warmth is covered by heat pump with the power of 39,5 kW, except in peak times. That represents only 1/3 of the power calculated for conventional heating. • For cooling we cover up to 80 % needs with geothermal energy through ground probes with passive cooling, the rest comes from the heat pump. • Apart from the described energy-saving effects, which has reduced primary energy needs from 110.000 kWh to 38.500 kWh a year, this project has considerable environmental effects, reducing CO2 emissions by 20 tons a year and CO in NOx by 35 kg a year.

15. Use of renewable energy sources for heating and cooling in the office building Project was realized by: INVESTOR: Kostak d.d. • Božidar Resnik, B. Sc. Mech. Eng. - project manager • Željko Horvat, B. Sc. Civ. Eng.- project co-ordinator • Biljana Šepetavc, B. A. Civ. Eng. - construction manager PROJECT ENGINEERING: Savaprojekt d.d. • Tina Božičnik, B. Sc. Arch. - architecture of the building • Goran Šalamon, B. Sc. Civ. Eng. - construction of the building • Mitja Lisec, B. Sc. El. Eng. - electro installations Bahč d.o.o. • Edo Bahč, B. Sc. Mech. Eng. - mechanical installation project