As a basic foundation for this study, expenses of exploitation are used, electric and gas bills, as well as general costs and expenses in the present Airport City business complex in Belgrade (ACB). To improve energy efficiency of similar buildings, the authors of this study wanted to present the various investment possibilities concerning energy saving. ACB is representative of typical (modern) business complexes that are being built intensively in Serbia and throughout Europe. Today, most similar constructions are designed in similar manner, with air cooled chillers on the roofs of the buildings. These installations are simple and less expensive for investors, quicker to erect, and much cheaper for commissioning. However, over an exploitation period of 15 years, it was proved that energy waste is much higher in these installations, which implicates a rise in cost of monthly fees. Ultimately, common citizens are paying for this through various products and services. At the time of writing of this study, at least six similar complexes are in the planning phase to be constructed in Belgrade. The suggestions in this study can be implemented on other complexes with some or no modification. The basic idea of this study is to demonstrate an analysis of the investment and the exploitation wages with regard to the payback time for an investment in CCHP trigeneration. On the one side, the example of a plant with boiler and air cooled chillers will be used, vs. CCHP with gas cogeneration on the other side. The basic structure of the building is a core and shell structure with an aluminum-glass façade. The height of the building is 35 floors. Cooling and heating calculations have been done using HAP software (Hourly Analysis Program).

Keywords: trigeneration, CCHP, absorption chillers, energy savings, economic analysis

Research paper – Ivan Glisic, B.Sc.M.E., Goran Vuckovic, MSc.M.E., Aleksandra Sretenovic, B.Sc.M.E., September 2009

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