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Energy efficient renovation of the existing housing stock is imperative to reduce building energy consumption since the building sector in Europe accounts for an estimated 40% of the energy used from all sectors and more than 80% of the buildings today will still exist in 2020. Following Europe’s energy objectives, the paper investigates, based on the European Union Directives, the current energy refurbishment rates and examines the future energy performance of the Cyprus housing stock, in order to determine if they are adequate in achieving the Europe energy targets. The research focuses on pilot houses in Cyprus, which include dwellings from all typologies as classified, according to the IEE project EPISCOPE. The houses were monitored and based on the collected data and the performed simulations, their current and future energy performance are presented in the form of Energy Performance Indicators (EPIs). From the study, it is observed that with the current trends the national climate protection energy targets are unattainable. This is mainly due to the inadequate rate and depth of energy refurbishment of the existing housing stock and the ineptness of the Directives to address effectively the reduction of the cooling energy needs in the new constructions. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes the mathematical modeling of vertical and horizontal GHEs (ground heat exchangers) and compares their efficiency. The model used calculates the heat flow in the fluid, tubes, grout and ground. The vertical U-tube GHE is represented by two 100 m lines, embedded in four different types of ground with an additional bottom base. The horizontal GHE consists of four 50 m tube lines embedded in three ground layers. The initial ground temperature for all cases examined matches real data acquired in June at a location in Cyprus and the simulation results for the vertical GHE are validated using measured data showing very good agreement. Further simulations with the vertical GHE show that when the initial ground temperature rises, the mean temperature of the GHE fluid increases proportionally. Comparisons between horizontal and vertical GHEs reveal that under the same operating conditions and center-to-center distances of the tubes, the vertical GHE keeps a much lower mean temperature. Simulations for a horizontal GHE, for a 50-h of continuous operation period and 24 °C initial ground temperature, show that the mean fluid temperature can remain lower than that of the vertical GHE if the center-to-center distance of the tubes increases to 1 m. [Copyright &y& Elsevier]