Study on Technical and Economical Solutions for Improving Air-conditioning Efficiency in Building Sector

Buildings are responsible for 40% of energy consumption and 36% of CO2emissions in the EU, according to United Nations Environment Programme (UNEP). The construction sector is developing since 2013 so in the future the energy consumption will increase very fast. As a result, renewable energy sources represent one of the main directions in reducing conventional energy consumption in buildings. In this paper the authors analyze solutions for decreasing the energy consumption required by the air-conditioning system in an office building of 6466m2, located in Bucharest. The current air conditioning solutions are the classical ones, based on either fan coils, supplied with chilled water of 12/7 °C, or air-coolers, as part of an Air Handling Unit (AHU). In the latter case, the cooled water is prepared by a vapor compression refrigeration unit chiller of 190 kW cooling capacity, working with R22. The solutions analyzed in this paper consider each of the following alternatives: a. Heat recovery from the exhausted air by using a heat exchanger integrated in the AHU; b. Replacement of the vapor compression refrigeration unit chiller with an one stage lithium bromide/water absorption refrigeration unit driven bysolar energy; c. Coupling the above mentioned solutions. All these solutions are discussed and analyzed from both technical and economical points of view.