AIVC - Air Infiltration and Ventilation Centre

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thermal mass

Dynamic performance of displacement ventilation in a lecture hall

An accurate temperature gradient calculation is essential for displacement ventilation (DV) system design, since it directly relates to the calculation of the required supply air flow rate. Inaccurate temperature prediction can cause the poor thermal comfort and w sizing of the ventilation and cooling systems.

The influence of thermal mass on the predicted climate cooling potential in low energy buildings

Even in Northern European climates, overheating in many Nearly Zero Energy Buildings is a barrier to year round occupant satisfaction with the indoor thermal environment. Improved energy performance and enhanced thermal comfort should not be perceived as a rigid dichotomy of concepts. However, an acceptable thermal environment, during extended cooling periods now present in NZEB’s, can come at a high energy cost if mechanical cooling is used.

An interface of night ventilation and mass structure for passive cooling design strategy in Ghadames traditional dwellings

The effectiveness of night ventilation strategy for residential buildings in the old town of Ghadames has been investigated in this study. Methods of field surveys including observations, temperature measurements and interviews were conducted to determine the characteristic building parameters and strategies including window patterns and space organisation that mostly contributed to achieve an efficient indoor comfort conditions especially at night summer time. Results showed that skylight openings can be a good window pattern for enhancing night ventilation in hot arid climate.

Cold storage in the thermal mass of buildings using night ventilation. Experimental analysis

An experimental analysis of the night ventilation technique for cooling in buildings, was performed in a test cell with the aim of establish the potential of this technique in two scenarios: a) when the air-stream is in poor contact with the thermal mass and b) when the air-stream is in close contact with the thermal mass of the test cell. The test cell is a small one-room building equipped with instrumentation for measurement and control the night ventilation following a strategy based in the values of indoor and outdoor temperatures.

Impacts of control strategies on light and heavy radiant floors in low energy buildings by Modelica simulation

The decrease of heat demand in low energy build-ings, very sensitive to solar and internal gains, and the development of new HVAC systems call for a reexam-ination of the usual modeling approaches in building simulation. A focus is brought on an air-to-water heat pump plugged to a radiant heating floor (RHF) by a hydraulic loop installed in a typical low energy dwelling. Using a RADTEST evaluated Modelica slab model, several floor thermal masses under four differ-ent control strategies are compared to determine their impact on HVAC system performances.

The performance analysis of natural ventilation for building cooling in Changsha city, China

As a passive cooling strategy, natural ventilation is an energy conservation technology with great developing potential. The typical technologies of natural ventilation include night ventilation and natural ventilation with heat storing materials. The factors which affect ventilation include technique parameter, climate parameter and building’s parameter. The natural ventilation in summer in a typical building in Changsha City, which locates in hot summer and cold winter area, was measured.

Parametric analysis of environmentally responsive strategies for building envelopes specific for hot hyper arid regions

The deep hot hyperarid valley between Israel and Jordan presents unique design and construction challenges in terms of energy conservation and thermal comfort. Winters are relatively mild, summers are extremely hot during the day and at night the air temperature remains above 25°C.  Such conditions present real challenges in this sparsely populated yet rapidly developing region. Such development depends on the ability to provide acceptable indoor environments at a low energy investment.

Accessing the Thermal Mass above Suspended Ceilings via a Perimeter Gap: a CFD Study of Naturally Ventilated Spaces

There is a growing desire to reduce peak temperatures within non-domestic buildings by accessing the thermal mass of separating floors. These floors are typically formed of concrete and can store reasonable amounts of heat. Unfortunately, they are usually thermally isolated from the room below by a suspended ceiling. Therefore, some architects try to access the concrete by leaving a perimeter gap in the suspended ceiling in each room to allow airflow across the underside of the separating floor. For visual and acoustic reasons, there is the desire to make this gap as small as possible.

The Impact of Several Construction Elements on the Thermal Performance of Solar Chimneys

Solar chimneys may provide enough ventilation to buildings when properly designed. Although many design tools, theoretical models and experimental studies have been reported, the impact of many design parameters such as the construction thickness, the thermal resistance of the walls, the absorptivity of the internal surfaces of the chimney, the thermal mass of the chimney and the type of glazing, is not well known. This paper aims to provide information on the optimum sizing of the above parameters.

Designing Thermal Mass in Naturally Ventilated Buildings

According to its location, thermal mass can be approximately classified into two types: external and internal. Internal thermal mass, such as furniture and purpose-built internal concrete partitions, does not expose to ambient temperature directly, while external thermal mass, such as walls and roofs, expose directly to ambient temperature variation. A virtual sphere method for modelling thermal mass is introduced and its application in building thermal mass design is discussed.