passive cooling

This paper aims at estimating the thermal comfort in environment created by a proposed passive evaporating cooling system. The evaporative effect from water falling along guides is used to produce a reduction in the temperature of the air entering the building.

This paper presents temperature and airflow measurements proving that ground-coupled fresh air intake ducts can have a significant cooling effect. Measurements at two Norwegian schools with such ducts, Jaer School and Medi School, show that the actual cooling performance after a three-day warm period is about 100 Wh/m2 of exposed concrete surface in the duct, with air velocity passing the surfaces of about 0.15 m/s. Our calculations indicate that this can rise to at least 200 Wh/m2 by increasing the air flow rate during the night.

The natural ventilation potential (NVP) is the possibility, or probability, to ensure anacceptable indoor air quality by natural ventilation only. A passive cooling potential (PCP)can also be defined, as the possibility to ensure an acceptable indoor thermal comfort usingnatural ventilation.

This paper describes current work to undertake a market assessment of the potential for the application of Passive Downdraft Evaporative Cooling (PDEC) to new and existing buildings in Southern Europe. The work is carried out as part of a European funded ALTENER project focussing on solar and passive ventilation for urban buildings. PDEC is a technique that may potentially become a substitute for conventional air-conditioning. The technique avoids the need for ductwork, fans and suspended ceilings, and reduces the need for refrigerant based cooling.

In moderate climates, one promising feature to reduce the energy demand of office buildings for air conditioning without reducing comfort is passive cooling by night ventilation. An office building has been designed, realised and monitored for a long time period in the framework of the German research programme solar optimised buildings. The night cooling of the office building has been realised by natural ventilation.

In order to save energy for building cooling during hot days in regions with cool nights, air circulation throughout the interior of the building has been envisaged as a means to lower the temperature of the building structural mass. In this way, energy required for cooling the building interior is reduced, due to lowered temperature of the wall, ceiling and other structural elements mass, and a greater storage of heat resulting from various heat gains the following day when air-conditioning is on.

The paper presents the effects of airflow access points on the passive modification of indoor air temperature in a partly roofed high-mass courtyard building found in moderate climate of southeast Queensland. Results of a field investigation reveal that despite sufficient shading within the courtyard, its air temperature and thus comfort levels depend greatly on the location of airflow access points in the building layout and section.

This research is based upon an examination of the natural cooling of the large reading room of the Bernardini(tm) Library in Lecce, Italy. The library is contained in an old building which is currently under restoration. Both indoor and outdoor temperatures as well as relative humidity were monitored, so that the most appropriate system to cool the library's large reading room in summer could be selected. The external walls were endoscopically investigated. Air is supplied by a displacement ventilation system and a system of buried pipes has been designed.

Describes details of a passive building component consisting of a ventilated roof with a maintained wet lower surface of the cavity over which the external air flows. Numerical simulations were carried out for thermal performance evaluation purposes of the thermal field, flow field and water vapour concentration of air within the duct. Suitable procedures were coded and linked to a commercial program for computational fluid dynamics, in order to obtain an estimate of the thermal cooling flux on the wet surface.

A performance evaluation of two passive cooling strategies is presented: daytime ventilation and night cooling, for a six storey apartment building in Beijing and Shanghai, China. A coupled, transient simulation approach is used in order to model heat transfer and air flow. CFD is used to simulate wind-driven ventilation, and Fanger's comfort model is used for occupant thermal comfort. States that the results indicate the superiority of night cooling over daytime ventilation, although there is a high condensation risk. For Shanghai neither were found to be suitable.