thermal stratification

The impinging jet ventilation system (hereinafter referred to as IJV) has been proposed as a new air conditioning ventilation system. Properties of indoor environment with this system using impinging jet are complicated. The present paper reports fundamental properties of indoor air with distributed interior heat generation load assuming an office. The experiment was conducted in the climate chamber of which floor area was 27.0 m2, and basic properties of temperature and CO2 distributions were investigated.

In the past, many churches were raised and in a church building no heating no heating system was installed, except a simple individual coal or peat stove, which could be rented by the churchgoers. The thick high stone walls of the church alleviated the fluctuations of the ambient air temperature and relative humidity. Accordingly, the indoor climate in the church building was quite stable. After the Second World War the living standard of the people increased and the increased prosperity also led to higher comfort demands in churches.

An ESP-r component model for gas-fired water storage tanks was developed within the context of the simulation for building-integrated cogeneration systems. Charged by the cogeneration unit with gas back-up, the tank can be used to satisfy both domestic hot water needs and space heating.

Thermal stratification in solar tanks is essential for a better performance of energy systems where these tanks are integrated. As a consequence, various technological solutions allow, on the one hand, to support stratification and, on the other hand, to decrease its disturbance. A state of the art on existing technologies and the various levels of modeling leads us to propose a pressure zonal model to predict annual performances of a generic solar tank.

In the sickroom, high indoor air quality and thermal comfort is essential for the treatment of patients.Therefore it is proposed to use displacement ventilation for the whole room ventilation and the radiantpanel for the thermal comfort of each bed. This study is intended to investigate validity of this system.This paper shows the experimental and calculated results of the displacement-ventilated room with onebed and one radiant panel. The vertical profile of contaminant concentration and temperature aremeasured and compared with the calculated ones.

This paper analyses buoyancy-driven natural ventilation assisted or opposed by winds in a building with thermal stratification. Theoretical analysis shows that the ventilation flow is mainly characterised by two air change parameters, namely a buoyancy air change parameter and a wind change parameter, as well as the ventilation openings. It also shows how the clean zone height is affected by ventilation openings. Our new analysis also reveals that the hysteresis behaviour found when uniform temperature distribution is assumed also exists in buildings with thermal stratification.

This paper attempts to answer questions like when thermal stratification is important and how to consider it in simple multi-zone models of natural ventilation. Both simple analytical solutions and comparison of CFO and multi-zone analysis suggest that the multi-zone modelling approaches with the assumption of uniform zonal air temperatures can significantly underestimate the neutral levels in buildings with large ventilation openings, indicating that the flow directions through some openings may not be correctly predicted.

This paper reports on research into the fundamental fluid mechanics mechanisms that lead to thermal stratification in a naturally ventilated room containing sources of heat, or cooling. This aspect of natural ventilation has an important influence on both air exchange rates and thermal comfort in a naturally ventilated space. Particular attention is paid to the situation where the major source of heat is a vertical surface, such as a wall heated by solar insolation, for example.