thermal mass

This paper touches on historic indicators of good hospital design such as sun, daylight and natural ventilation. Evidence is provided that recent trends in hospital design that lean towards more highly serviced buildings with fixed windows lead to higher levels of Sick Building Syndrome, nosocomial infections and SARS CoV-2 related infections and deaths than in naturally ventilated buildings with opening windows.

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.

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.

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.

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.

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.

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.

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.

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.

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.