Multiple Steady States in Buoyancy Driven Natural Ventilation

When designing natural ventilation for complex buildings, it is key to understand whether there is a unique solution for the flow, or if multiple flow regimes are possible. Here, we show that in a 2 storey open plan office type building, in which the floors are connected to a common atrium, two stable flow regimes may occur under identical conditions.

Study on the Individual Control System Considering Human Thermal Adaptation

This paper analyses an individual control system that accounts for human thermal adaptation.Although the conventional individual control system has been shown to provide a satisfactory level of thermal comfort, there are questions over its energy efficiency. It has therefore become urgent to develop a new individual control system that can ensure both energy saving and thermal comfort. In this study, the alleviation time is proposed as an energy-saving control strategy for the individual control system.

Analysis of a Local Heating System for Thermal Comfort: the Numerical Approach

Achievement of thermal comfort can be improved if individual control of the environment is allowed,namely through a local heating system (LHS), consisting of individually controlled radiant heating panels, adapted to a common office desk to a seated person. The coupling with of a new radiative module enhances the simulating capabilities of an existing CFD numerical model. The added improvements are applied to the evaluation of the thermal performance o the LHS. A comparative analysis clearly demonstrates the relevance of a due consideration of radiative exchanges.

Impacts of Non-Isothermal Task Conditioning System with Individual Control on Thermal Comfort and Productivity

Subjective experiments with a non-isothermal task conditioning system were conducted toinvestigate impacts of the system on thermal comfort and productivity in a climate chamber of Kanto-Gakuin University, Japan. All subjects participated in "default condition test: 26C / 50% RH" at first.Then a half of the same subjects participated in "standard condition test: 26C / 50% RH", and theremainder subjects participated in "task-ambient test: 30C / 50% RH + TAC", just one week later again separately. Thermal, humidity, comfort sensations, and other psychological factors were investigated.

Individually controlled office environments. Thermal comfort parameters determination

This paper presents the main results of a research on an individually controlled office environment. The research was carried out in a laboratory that counts on an air conditioning system with underfloor air supply and individual airflow control devices for personalized thermal comfort. The evaluation was based on quantitative and qualitative data acquired respectively by means of comfort variables local measurements and people participation. The main results refer to the thermal comfort parameters proper to the referred environment and parameters for the system operation.

Indoor air pollutants - Part 2 : description of sources and control/mitigation measures

The second part of the VIP Indoor air pollutants concerns the sources of pollutants and effective measures to control them or to make their impact on occupants less severe.

Remedial measures, building technology and their cost-effectiveness

The author describes the most important indoor air related health determinants and a table gives information on the source characterisation of health determinants indoors, their control method along with examples of actions that could be taken by national level bodies or societies.

Numerical and experimental device for local control of ventilation

Local control of ventilation in large buildings is considered to be a main issue in energy savings regarding the huge energy losses that are usually induced by such large volumes. An efficient ventilation system and the development of local control ventilation strategies could prevent large buildings from having an unsuited or overvalued ventilation and reduce significantly the energy consumption.

Hybrid demand controlled ventilation system

The purpose of this system is to provide one improved ventilation system allowing significant good indoor air quality, heating (and cooling) energy savings and acceptable thermal comfort on summer, by using especially renewable energy.This concept is based on sensors measuring relative humidity in bathroom and kitchen, occupancy in bedrooms and toilet, and agitation (i.e.

Optimization of hybrid air-conditioning system with natural ventilation by GA and CFD

This study aims at the development of an optimal design tool using a genetic algorithm (GA) andcomputational fluid dynamics (CFD). To represent a realistic building environment, random variables(fluctuating outdoor conditions), passive control variables (model variables) and active control variables (HVAC system) were set up. A combination of designs are determined based on the relationship between the fluctuating outdoor conditions and the HVAC system in the optimization inquiry.