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Climate change is an increasingly important global concern at this moment. Fossil fuels meet a majority of world energy needs and because buildings are large energy consumers, they are also a major contributor to global carbon emissions and greenhouse gas (GHG) production. It's important for the European Union, including Romania to avoid these problems. Buildings are responsible for 40% of energy consumption and 36% of CO2 emissions 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 airconditioning system in an office building of 6466 m², 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 190kW 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 by solar energy; c. Coupling the above mentioned solutions. All these solutions are discussed and analyzed from both technical and economical points of view. [ABSTRACT FROM AUTHOR]

Copyright of Romanian Journal of Civil Engineering / Revista Română de Inginerie Civilă is the property of Matrix Rom and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper refers to the use of ice-slurry, as an intermediary phase changing cooling fluid, in air-conditioning. Ice-slurry is provided by a scraper-type generator that is part of a single stage compression system working with R404A, as primary refrigerant. A mixture of ice-slurry, water, and talin (10% mass concentration) represents the secondary cooling medium. This was used in a heat exchanger of classical type, namely an air cooler, with aluminum fins, of 0.1 mm thickness. This paper reports experimental results of ice-slurry used as cooling fluid for airconditioning consumers of various cooling capacity demands. Experiments have been carried out using two different ice mass fractions, namely approximately15% and 20% and two different air volumetric flow rates, namely Qair = 3000 m3 / h and Qair = 2000 m3 / h The cooling capacity of the ice-slurry generator has been experimentally validated by simultaneously determining the thermal capacity for the evaporator (as a function power input to the compressor), for the air-cooler and air heaters. [ABSTRACT FROM AUTHOR]

Copyright of Romanian Journal of Civil Engineering / Revista Română de Inginerie Civilă is the property of Matrix Rom and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper develops a theoretical and experimental study on convective heat transfer characteristics in a mini-channel type air-cooler, operating with ice-slurry. Although ice slurry is usually employed as a secondary fluid in air conditioning systems, this paper investigates its behaviour as a primary fluid. Furthermore, since previous investigations on ice slurry mostly referred to plate heat exchangers, little information is yet available in the literature regarding ice slurry use in mini-channel heat exchangers, this study employed several correlations recommended by the open literature for binary mediums, such as ice-slurry, in order to identify the best fitted correlation in terms of best agreement with the experimental results obtained for the given geometrical configuration of the heat exchanger, ice mass fraction, and specific operating conditions. Besides the theoretical study, the authors have also developed an experimental study and a comparative analysis of theoretical vs. experimental results with respect to the heat transfer coefficient on ice-slurry side as a function of ice mass fraction, of ice-slurry flow rate and air flow rate. [ABSTRACT FROM AUTHOR]

Copyright of Romanian Journal of Civil Engineering / Revista Română de Inginerie Civilă is the property of Matrix Rom and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)