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This paper investigates the influence of natural ventilation on the indoor thermal environment in the residential vernacular architecture of Cyprus. The research was performed through a field study investigation during the hot summer period. The investigation included different ventilation strategies, i.e. daytime, full-day and night-time ventilation. Furthermore, in the case of night ventilation, different window opening patterns, i.e. single sided and cross ventilation, were examined. The results show that night ventilation is the most effective strategy for passive cooling in vernacular dwellings during the hot summer period, compared to the two other ventilation strategies. This strategy reduces peak indoor air temperatures and also improves indoor thermal conditions during the following day. Furthermore, cross ventilation, during night-time takes full advantage of the relatively low outdoor air temperatures and cools down the building envelope in the best possible way. The findings are presented in a comparative manner and evaluated in a quantitative way, offering valuable information in the relevant field. The paper presented herein confirms the positive contribution of natural ventilation for cooling in the vernacular architecture in Cyprus as well as in other areas of the eastern Mediterranean region, where similar climatic conditions, building typologies, construction materials and techniques can be found. [ABSTRACT FROM AUTHOR]

The paper focuses on the methodology for modeling the thermal response of vertical Ground Heat Exchangers (GHEs), when imposing underground water flow and a temperature gradient on the numerical model to represent the temperature of the depth profile. Four underground layers with different properties were studied, in order to identify their contribution in the total response of the GHE. In more detail, vertical GHEs in water saturated and dry soils, with or without water flow, are modeled with the equations that govern the heat transfer being presented. The numerical solution of the equations is based on the Finite Element Method (FEM) with boundary values. The model is validated with actual data of a Thermal Response Test (TRT) carried out in Lakatameia, Cyprus. Using the validated model, the heat injection rate of a GHE is investigated by determining the effect of the (a) summer and winter mode of operation, (b) underground temperature variation in depths smaller than 7 m due to daily and seasonal changes, (c) borehole radius, (d) borehole grout properties, (e) U-tube diameter, (f) U-tube leg and borehole centers distance, and (g) groundwater flow velocity. [ABSTRACT FROM AUTHOR]

Hotel units are responsible for a significant proportion of energy consumption and carbon dioxide emissions in the tourist sector. This paper focuses on the energy and environmental performance of hot-water production systems utilized by high class hotels in Cyprus in order to formulate appropriate carbon emission mitigation strategies. The main systems used are boilers fired by Liquefied Petroleum Gas or Diesel oil, air-source heat pumps and flat plate solar collectors. The results show that the combination of air-source heat pumps with flat plate solar collectors leads to the lowest primary energy consumption. Therefore, improving the sustainability of the tourism sector in Cyprus requires to phase out the usage of boiler systems that are currently in use in almost all four star and five star hotels and promote the use of solar thermal systems in combination with air-source heat pumps. These findings are relevant for island states and other popular tourist destinations sharing similar characteristics with those of Cyprus and provide a framework for national authorities to plan an appropriate energy and environmental upgrade of the hotel stock. [ABSTRACT FROM AUTHOR]

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: The significance of the residential building sector in terms of energy consumption is well acknowledged. In this view the knowledge of the way the residential building stock of Cyprus behaves in terms of energy consumption is quite valuable since it will assist policy makers to formulate targeted measures aiming the improvement of energy efficiency and setting current legal standards and benchmarks in the energy performance certificate, a requirement of the 2002/91/EC Directive. Unfortunately, the existing knowledge on this subject is quite poor. As a remedy a research project supported by a national research grant is in operation since December 2008. This paper presents the outline, goals and methodology of this research project and the findings regarding the energy behaviour and other characteristics of the residential building stock of Cyprus. From the analysis of the results for 500 residential buildings, it seems that the energy demand and primary energy required is lower than that of other European countries. Moreover, it seems that the age of residential buildings has low correlation with the energy demand while in contrast with other Northern and Central European countries, it is clear that the contribution of cooling energy requirements to the overall energy demand is quite significant. [ABSTRACT FROM AUTHOR]

• Indoor conditions were monitored and subjective data from 606 people was collected. • The in-situ measurements often indicate temperatures out of the acceptable limits. • The acceptable temperature range allows for heat energy saving in the winter period. • Students' behavior is significantly determined by outdoor temperature. • The results comprise retrofitting guidelines for school buildings in southern Europe. This paper explores the impact of natural ventilation on the indoor thermal environment through an extensive field survey of educational architecture in Cyprus performed both during the winter and summer periods. The study included seasonal indoor and outdoor monitoring of physical parameters, as well as a questionnaire-based survey. The study shows that the naturally ventilated spaces on the upper floor demonstrate operative temperature below the acceptable comfort zone during the winter period, while during the summer period, the findings show the vulnerability of the occupants to summertime temperatures. During the winter, a closed classroom shows the best results in terms of operative temperature; however, this conflicts with the air quality. During the summer, the case of cross-ventilation, both during the day and night, is the most efficient and operative way to passively cool educational premises. Moreover, the results of the subjective survey demonstrate that most students feel comfortable in both the winter and summer demonstrating high thermal tolerance. The results of the current study can be applied to inform strategies for the improvement of thermal comfort and reduction of energy use in educational buildings, as well as the design of new educational buildings. [ABSTRACT FROM AUTHOR]