Cost-optimality of an office building with different small scale biomass-based co-generation technologies

The economic viability of using small-scale biomass -based co-generation heat and power (CHP) as a heating system for an office building, in Helsinki, Finland, using the Energy Performance of Building Directive (EBPD) comparative framework methodology is the aim of this study. Seven heating/cooling energy generation system package (H/C-EGSP) consisting of four CHP technologies with vapor compression refrigeration (VCR) cooling system comparing three conventional heating and cooling systems are investigated. The suggested energy efficiency measures consist of building structure measures; external wall insulation, window type, and envelope air-tightness, and system package of ventilation system, and daylight control getting 144 building combinations, and alongside the H/C-EGSPs, altogether 1008 cases. The res ults show that the investigated small scale biomass-based CHPs with low power/heat (P/H) ratio have cost optimal solution less than that with high P/H which have higher investment cost relating to higher associated electrical capacities as well as higher operational energy costs due to lower thermal efficiency. The pellet boiler and vapor compression refrigeration (PB-VCR) has the minimum cost optimal solution, among all H/C-EGSPs.These results are not affected when the sensitivity analysis is conducted under different real discount rates, different biomass-based CHP investment cost, and differ ent feed-in tariff for the surplus electricity exported in cases of the CHPs.