Energy audit certification and rating of school buildings in Greece

The present paper presents the results of the energy and environmental evaluation of ten school buildings in the Greater Athens Area. The research included measurements of the indoor air quality, evaluation of the situation of the building envelope, recording of energy and ventilation systems and generally all the systems that influence the energy output of the school buildings. Experimental investigations were performed in ten different schools and the concentration levels of CO2, CO and VOCs were measured.

Energy and comfort performance of natural ventilation system office buildings in China

This paper presents an analysis of energy and comfort performance of typical office buildings for summer cooling in five climate zones in China using the natural ventilation assessment tool, which is developed based on the integrated thermal and airflow model. Harbin, Beijing, Shanghai, Kunming and Guangzhou are selected as the five representative cities for Very Cold, Cold, Hot Summer and Cold Winter, Mild and Hot Summer and Warm Winter zones respectively. The cooling energy consumption with air conditioning system is compared to that with natural ventilation system.

Criteria to define limits for building airtightness. Airtightness of some Portuguese dwellings

The increasing concern on energy conservation in buildings and the increasing insulation level of buildings, lead to the introduction of limits for building airtightness, to minimize building heat losses. In some countries the recommended limits are very strict and could be difficult achieved with standard construction practices. Usually the limits are established according construction (best) practices and in some countries it takes in account the building type, ventilation system and weather. Usually those limits dont take in account the air flow rate for background ventilation.

CFD analysis of the effect of self-regulating devices on the distribution of naturally supplied air

Thermal comfort in living rooms or bedrooms is among others determined by the spatial distribution of the supplied ventilation air. In this work, the performance of a self-regulating (pressure-sensitive) air transfer device, in terms of air flow rate and human comfort, was investigated by means of CFD. Self-regulating ventilators limit the air supply rate according to the pressure difference across the ventilator as to reduce draught risks.

Blower door measurement of large buildings - with one or more blower systems

This article describes five blower door measurements – each made with a different objective – carried out on large buildings. Proof of air tightness is required to guarantee the operational capability of ventilation systems or to enable fire protection by

Atria for ventilation efficiency improvement in urban office buildings

In this paper the effects of atrium and other similar architectural design features (e.g. shafts) on ventilation efficiency are examined in a multi-storey office building. Attention has been given to simulate the use of the main entrances, the vestibules and the various shafts. An atrium and an non atrium solution were compared for the examined building. Stack effect was the dominating force and wind effect was present yet not significant, but enough to produce negative pressures at the area of the atrium, mainly due to the form of the atriums roof.

Assessment of improvement brought by humidity sensitive and hybrid ventilation/HR-Vent project

Introduced for the first time at 25th AIVC Conference in Prague in September 2004, the HR-Ventproject still delivers new rich teachings since its start in January 2004. Until December 2005, morethan 700 million data have been recorded on 180 extract units in 5 occupied collective buildingslocated in NANGIS (France).

Application of Phoenics to athletic halls with HVAC ventilation

The commercial general - purpose Computational Fluid Dynamics (CFD) code PHOENICS is used to study the indoor environmental conditions of a large, mechanically ventilated, athletic hall. The indoor space of the building was simulated in the PHOENICS environment and computations were validated against experimental data obtained during a ten-day campaign in the hall. Data included measurements of airflow characteristics at different indoor locations under different ventilation conditions.

Annex 41 - Whole building heat, air and moisture response

Combined heat, air and moisture (HAM) simulation at the envelope level and building simulation havebeen two separate activities for many decades now. In HAM-models, inside temperature and inside relative humidity are handled as known boundary condition, while all building simulation tools predict inside temperatures and net energy demand without any consideration for relative humidity.Things started to change when airflow modeling became doable.

Analysis method based on power balance as applied to wind driven flow

Currently, various studies have demonstrated some doubt about the accuracy of the orifice equation when applied to the calculation of cross-ventilation. As a result, a computational fluid dynamic (CFD) simulation is considered the best method of analyzing cross-ventilation properties under present conditions. However, repetition of CFD analysis to determine the optimum ventilation performance is particularly complex. Accordingly, a flow network model that corresponds to cross-ventilation was developed and suggested as a more efficient means of determining the optimal opening conditions.

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