The impact of temperature increase in Greece on the energy demand of buildings

The increase of the ambient air temperatures in urban areas during the past few decades, due to the heat island phenomenon and the warming of the lower atmosphere, has strong impact on the energy profile of buildings, the comfort conditions, the air pollution and the indoor environment, especially in the Mediterranean regions with hot climate conditions. The present paper focuses on the investigation of the impact of the temperature increase in nine Greek cities over the last forty years on the energy demand of buildings.

On investigating instantaneous wind-driven infiltration rates using CO2 decay method

Carbon dioxide has been already recognized as a potential tracer gas towards estimation of the mean air exchange rates (ACH) of a room or building. The wind direction and mean wind velocity have been also clarified as critical factors that affect the air infiltration. In this study, the indoor CO2 concentration is detected and logged at three specific points in an office room for seven selected measurement-periods. The decay method is used to estimate the leakage rates.

Field observation of cooling energy saving by the high reflectance paint

Cooling energy savings in a building with the roof coated by high reflectance paint are examined. It is difficult to recognize the cooling energy savings by using the data observed every hour. It is assumed that factors affecting to cooling energy load are the internal heat generation, the set temperature, weather conditions, etc.

Composite materials for renovation of roofs in existing buildings

The EPBD directive (91/2002/EU) paved the way for the European Union member states to develop and apply a holistic approach on the building’s energy performance. It is documented that buildings’ energy consumption represents 40% of the total energy consumption in Europe, a significant figure when compared to the industry and transportation sector. Respectively the CO2 emissions are calculated to be around 30%.  A series of published data indicates that the uninsulated or poorly insulated roofs account for up to 25% of energy losses.

Experimental performance characterization of a new single room ventilation device with heat recovery

Nowadays, important efforts are made to reduce the residential building energy consumption. In this context, a growing interest for heat recovery ventilation has been observed during the last decades. The present paper focuses on a new single room ventilation with heat recovery. Double flow ventilation is achieved through the integration of the unit into windows ledges. The developed device is particularly suitable compared to traditional centralized heat recovery ventilation units for retrofitted houses due to the absence of air extracting and air pulsing ducts through the house. 

Study on the appropriate selection of urban heat island measure technologies to urban block properties

Toward the appropriate selection of urban heat island measures technology in the street canyon, the introduction effects of the technologies in the typical street canyon are analysed by the model calculation. It is appropriate to use street trees for the improvement of the thermal environment on the sidewalk and high reflectance paint or water-retentive pavement for the reduction of surface temperature on the roadway. Reduction of solar radiation gain to the sidewalk pavement surface is dependent on the location and area of the shadows by street tree.

Re heat recovery systems necessary for nearly zero energy buildings in mild climates?

Heat recovery ventilation became an unavoidable element of a passive or nearly zero energy building in Northern and Central Europe countries. Airtightness standards became very tight so that the building is compatible with this ventilation system. As frosting of heat recovery unit consumes a lot of electrical energy, a buried pipe system to smooth air temperature variations became also a necessary system in order to avoid defrosting.

Sanitary aspects of domestic ventilation systems: An in situ study

With the continuous improvement of the energy performance of buildings, ventilation plays a crucial role in the control of pollutants from indoor sources and related comfort and health effects. However, the ventilation system itself could possibly also be a source of indoor air pollutants such as microbial contaminants. Profound scientific and technical knowledge on the impact of the design, installation and maintenance on the real performances of ventilation systems is currently lacking.

Filter pressure drop control in balanced ventilation systems for dwellings

As a consequence of the energy and environmental issues, it is necessary to reduce the energy consumption of buildings. So, the air tightness of building envelopes is being improved and the air change rate due to infiltration is decreasing. It is then even more important than in the past that the buildings are equipped with well designed and working ventilation systems in order that the air renewal within buildings is ensured. In this context, the market of balanced ventilation systems with heat recovery for dwellings is growing. 

Cool roof for passive cooling: simulations of an existing building in southern Italy

Roofs are the envelope component more severely hit by solar radiation in summer (1470 kWh/m2 on average in Italy), hence one may expect that using cool materials on the finishing layer of a roof should provide a significant reduction in the heat flow entering the building, with sensible relief in terms of building cooling load.  In this paper a case study is presented, based on the dynamic simulation of an existing office building in Catania (Southern Italy).

Pages