Airbase publication

In 2009 the regulatory framework and the business environment for the construction sector has changed significantly in order to reduce the CO2-emissions of existing and new buildings. New buildings have to be net-zero after 2020, some public buildings already after 2018. Several national Governments try to achieve a net-zero primary energy balance for the complete building stock until 2050 which is truly a grand challenge. In order to reach these goals two things have to be done: 

The present study aims at investigating different methodologies and standards for measuring and calculating solar reflectance and infrared emittance, the two main properties characterizing cool roofing materials. In order to achieve this goal, an interlaboratory comparison testing has been set up among several laboratories that are members of the European Cool Roofs Council.

Soil gas pollutants (Radon, VOCs, etc...) entering buildings are known to pose serious health risks to building’s occupants, and various systems have been developed to lower this risk. Soil Depressurization Systems (SDS) are among the most efficient mitigation systems protecting buildings against soil pollutants. Two kinds of SDS are currently used: active and passive systems. Active systems are mainly use fans, which enables the mechanical sub-slab’s air extraction. Passive systems use natural thermal forces and wind effect to extract air from the sub-slab.

Cooling loads in office buildings with large glazing facades are increase due to solar radiation penetrating the windows and over-heating the rooms. Moreover solar radiation provides natural lighting in the rooms, which might be higher than expected in the summer months and causes glare problems. In order to balance optimally between the reduction of cooling loads and natural lighting a controller can be applied to select the best combination between the position of blinds and whether the artificial lights will operate or not. 

The aim of this paper is to present an advanced controller for artificial lights developed and tested using validated light models for several rooms in two European Hospitals located in Chania, Greece and Ancona, Italy respectively. Fuzzy techniques have been used for the architecture of the controller. The efficiency of the controllers has been tested using validated models of the RADIANCE back-wards ray tracing model.

Ensuring the thermal comfort and improving the ventilation effectiveness are important goals designing ventilation systems. This study describes effects if the ventilation system of a room is run in an instationary operation mode. That means that the inflow velocities are varied in time. The influence of different periodic times of the variation of the inflow velocities is investigated numerically with CFD simulations. The CFD simulation setup is validated by comparing CFD results with experimental data (Aachen Model Room).

Worldwide the food system is responsible for 33% of GHG emissions. It is estimated that by 2050, total food production should be 70% more than current food production levels.   In the UK, food chain is responsible for around 18% of final energy use and 20% of GHG emissions. Estimates indicate that energy savings of the order of 50% are achievable in food chains by appropriate technology changes in food production, processing, packaging, transportation, and consumption.  

High urban temperatures are observed during the last 100 years due to heat island phenomenon. The effect is intensively pronounced even in small sized cities by temperature differences between rural and urban environment reaching even 6 oC. In order to keep the phenomenon under control, mitigation strategies, especially concerning cool roofs has been established. Under hot and arid climates roof temperatures reach almost 70 oC and about 50% of heat enters into buildings through roof slab.  

The present study aims at investigating concentration levels of particulate matter PM10, PM2.5, PM1 and UFP as well as of total airborne fungi and their vertical distribution in the indoor and outdoor environment of school classrooms. Measurements were performed in two naturally ventilated high schools in Athens, from January until May 2011. Indoor concentrations of the pollutants will be presented per floor level and indoor to outdoor (I/O) concentration ratios will be estimated as a function of the floor height.

In this study, the TRNSYS simulation engine was used to investigate the shading and cooling effect of roof added photovoltaics. The local weather conditions were introduced in the data reader component. The sol air effective temperatures were modeled in the roof –air boundary layer, while a single zone model was used for the heat transfer calculation, both in bared and PV shaded  roof. The simulation was validated by experimental data of a PV installation at the roof of the Department of Environmental & Natural Resources Management.