PR2007

A conference report from the 28th AIVC and 2nd Palenc Conference  " Building Low Energy Cooling and Ventilation Technologies in the 21st Century" held in Crete, Greece, 27-29 September 2007. This overview set is focused, mainly on ventilation aspects.

The requirements for good indoor air quality and energyefficiency have often been considered to conflict with each other, however, buildings with low energy consumption in Europe seem to have also a lower rate of building related health symptoms. This indicates the importance of proper design, installation and qualified, well trained operational personnel, who understands both the requirements for good indoor air quality and energy efficiency.

In order to show the efficiency of Phase Change Materials(PCM) in building walls we have used the software CODYMUR. The aim of the simulation is to evaluate the optimal thickness of the material and its behavior for different speeds of temperature evolutions in the room. The conclusion deals with the behavior of the wall due to the phase change phenomenon with a non linear thermophysical properties in comparison with a pure sensible storage layer.

The Clathrate Hydrate Slurry (CHS) of Tetra-n-Butyl-Ammonium Bromide (TBAB) comes into being under normal atmosphere when aqueous TBAB solution is cooled to 5-12 . It is a kind of high-density latent-heattransportation medium. CHS of TBAB has far higher cold-loading density than that water does, and can be transported easily through pipeline. So it can save the circulating pump power, and isvery promising to apply TBAB CHS into central air-conditioning or district coolingsystems as a new secondary refrigerant. In this paper, the pipe flow experiments of TBAB CHS are carried out.

Many schools today have a need for artificial cooling over the year but most of the classrooms do not have any cooling capacity installed. This fact results in high room temperatures as well as poor thermal comfort. However, new research shows that an increased air velocity during short periods can create an improved temperature tolerance in human beings. The high velocity pulses are short, a few minutes, so that the air movements should not be perceived as draft. This means that, within certain limits, it is possible to let the room temperature rise with maintained comfort.

This paper concentrates on the results of sustainability caused by Courtyard as a climatic element in Iranian traditional architecture of hot-arid regions. Traditional architecture of Iran is perceived sustainable for having sustainable features. It is able to response to environmental problems from a long period.

New solar energy systems with efficient energy output and advanced aesthetics have been developed at the University of Patras last 20 years. Among them some collector types are effective in aesthetics and energy output, as the solar collectors with colored absorbers and the stationary CPC type collectors. The building integration of air cooled photovoltaics aiming to contribute to building ventilation and of hybrid photovoltaic/thermal (PV/T) systems, to provide heat and electricity, are solar devices of particular practical value.

Social, financial, energy and technical data from about 1110 households have been collected during 2004 in the major Athens area. The sample has been divided in seven income groups and a detailed analysis has been performed. Important conclusions have been drawn regarding the quality of households, the operational conditions and the energy spent per income group. Low income people are more likely to be living in old buildings with poor envelope conditions. The cost per person and unit area is much higher for the low income group for both heating and electricity.

Psychometric diagram, or diagram of humid air, was establishedby three authors in a period of 10 years, very possible independent from one another. It is interesting how three men got the same idea in three very different locations of the globe, at a time when there were no radios,good phones or electronic connections. It was difficulttime for close dialogs and exchange of informationbut still it happened that three men, nearly in same time have done the same contribution to science and art of HVAC&R.