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

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 heatinguse 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 mechanical room, 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 years ago:

Today:

Design of the buildingReinforced concrete skeleton with a structural glass faade 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 glass foam - Technopor for insulation Exterior shading

Heating and cooling scheme Legend

Ground probe Heat pump (Brine/Water)Hot water storage cylinder Cold water storage cylinderSanitary water cylinder Gas-fired condensing boiler Air conditioning deviceRadiatorsFloor heating ConvectorsTemperation of concrete mass

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.

Cooling of the building Cooling with heat pump.

Air temperation and ventilation with air-conditioning with recuperation up to 75%.

Accumulation in concrete core.

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.

Investment & costs Energ. eff. construction Trad. construction

Investment for heating & cooling 134.000134.000Gas boiler house with equipment 14.800Ground probe with equipment 52.957Together 186.957148.800

Difference in the investment 38.157

Heat loss from the building 105.076 kWh 112.276 kWhUse of gas for heating 11.856 Sm3Heat gain of the building 28.039 kWh 36.451 kWhUse of electricity for cooling ( = 2,6) 14.020 kWh

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 kWhActual measured values Use of primary energy sources for heating 34.820 kWh 2.850 Gained heating energy 92.630 kWhUsed energy and gained energy ratio 2,66Savings at energy effective construction 77.456 kWh4.049

Cooling - summer 2007Heat 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 kWhUsed energy and gained energy ratio 6,58Savings at energy effective construction 12.128 kWh 1.140

Savings - season 2006/0789.584 kWh5.189 Investment return period 7,35 year

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

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.

Use of renewable energy sources for heating and cooling in the office building

Project was realized by:

INVESTOR: Kostak d.d.Boidar Resnik, B. Sc. Mech. Eng. - project managereljko Horvat, B. Sc. Civ. Eng.- project co-ordinator Biljana epetavc, B. A. Civ. Eng. - construction manager

PROJECT ENGINEERING: Savaprojekt d.d.Tina Boinik, B. Sc. Arch. - architecture of the building Goran alamon, B. Sc. Civ. Eng. - construction of the buildingMitja Lisec, B. Sc. El. Eng. - electro installations

Bah d.o.o.Edo Bah, B. Sc. Mech. Eng. - mechanical installation project