CFD

Personal displacement ventilation (PDV) is a new ventilation concept that intends to combine the positive features of displacement ventilation with those of task conditioning or personalized ventilation. PDV is expected to create a micro-environment  around the occupant to control the environment individually.

This paper describes the development of computational thermal manikins (CTMs) to be used in a coupled simulation envrionment to simulate the human thermoregulary response in buildings. 3D graphic design and engineering tools have been used to create CTMs with different postures and clothing insultation levels. Computational fluid dynamics (CFD) simulations of a nude CTM in a space with displacement ventilation has shown good agreement with experimental data of measured convective and radiative heat transfer coefficients.

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.

The moving human (MH) influences the airflow and contaminant distribution, this paper use the commerce software FLUENT6.2 to simulate the influences of the MH to the airflow and TVOCs distribution in both mixing ventilation and placement ventilation. In a three-dimension ventilation room, a pollutant source (TVOCs) was located on the floor and a flesh in a certain zone moving was assumed,  and the unsteady, k-ξ turbulent model be used, According to the simulation results, we studied the influence of MH in the indoor air quality in both mixing ventilation and displacement ventilation.

Building indoor environment quality (IEQ) has received growing attentions lately because of the extended time people spend indoors and the increasing reports of health problems related to poor indoor environments. Recent alarms to potential terrorist attacks with airborne chemical and biological agents (CBA) have further highlighted the research needs on building vulnerability and protection.

This paper discuss about characteristics and energy performance of personal air-conditioning system for a general multi-bed patient’s room. Two types of personal air-conditioning systems are evaluated by the laboratory experiment. Energy performance of a peri-counter FCU (a conventional) air-conditioning system is simulated by CFD to compare with that of personal systems. Compared with the conventional system, personal air-conditioning system has an advantage from the viewpoint of amenity improvement, but may consume more energy for cooling in the system.

Energy recovery ventilator (ERV) is generally installed in an air-conditioning system to recycle the cooling load of exhaust air. However, air conditioning systems with the single ERV can not meet with outdoor air load and indoor cooling load in summer, which will cause fluctuation of indoor temperature. The goal of this study is to analyze such a fuctuating scenario of the indoor temperature. CFD and subjective evaluation are used in this study.

As a comfortable and energy-efficient air conditioning system, the application of radiant floor heating system is increasing greatly used in the north of China. Now, more and more people begin to be aware of the problem of thermal comfort degree in radiant floor cooling room. This study aims at developing a radiant floor cooling system using the existing radiant floor heating system. Unlike an all-air cooling system, the radiant floor cooling system could remove the cooling by convection and radiation.

It is well known that humidity influences cooling load, thermal comfort and durability of buildings and various items in them. Many works on prediction of humidity variation in a room have regarded the humidity as unique in a space. However, it does depend on air movement. This paper describes calculations of minute moisture distributions in a room affected by moisture buffering of porous walls. The air velocity distribution is calculated by CFD using two different turbulence models. Then the heat and vapor transient transport in walls and space is calculated.

Natural ventilation is rapidly becoming a significant part in the design strategy of buildings in situations where electricity is scare or non-existent and saving energy becomes highly important. The aim of present work is to reduce the ceiling temperature by natural ventilation through different opening locations (one window in the front façade and the other window in the rear wall) with sill height ratio of 0.27, 0.36, 0.45, 0.54, and 0.63.