Predicting natural ventilation in a two-zone building driven by combined forces

Natural ventilation relies on less controllable natural forces so that it needs more artificial control, and thus its prediction, design and analysis become more important. This paper presents both theoretical and numerical simulations for predicting the natural ventilation flow in a two-zone building with multiple openings which is subjected to the combined natural forces. To our knowledge, this is the first analytical solutions obtained so far for a building with more than one zones and in each zone with possibly more than 2 openings.

Integration of a multizone airflow model into a thermal simulation program

An existing computer model for dynamic hygrothermal analysis of buildings has been extended with a multizone airflow model based on loop equations to account for the coupled thermal and airflow in natural and hybrid ventilated buildings. In water distribution network and related fields loop equations have been widely used to resolve the flow of water and other fluids. In the field of natural ventilation the loop equation method have rarely been used in spite of its quality.

The impact of traffic-related pollutant on indoor air quality in buildings near main roads

Traffic–related pollutant has been recognized as an air pollution hot spot due to its large emission rate and great health impacts for the exposed population. In the present investigation, a computational fluid dynamics technique is used to evaluate the effect of traffic pollutions on indoor air quality of a naturally ventilated building. The transport of street-level nonreactive pollutants emitted from motor vehicles into the indoor environment is simulated using the RNG k-ε model of the turbulent flows and the pollutant transport equations.

Uncertainty and sensitivity analysis of natural ventilation in high-rise apartment buildings

Quantification of natural ventilation rates is an important issue in HVAC system design. Natural ventilation in buildings depends on many parameters whose uncertainty varies significantly, and hence the results from a standard deterministic simulation approach could be unreliable.

Buoyancy-driven natural ventilation of a room with large openings

The buoyancy-driven natural ventilation of a room with large lower and higher level openings is investigated by both theoretical analysis and CFD simulation. Pressure-based formulae are developed for the prediction of the height of neutral plane and airflow rate, and three different flow modes are identified according to the position of the neutral level: (I) when the neutral height is at intermediate level of the lower opening; (II) when the neutral height has no intersection with openings; (III) when the neutral height is at the intermediate level of the higher opening.

Effect of natural ventilation and wind direction on the thermal performance of a building ceiling

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.

The performance analysis of natural ventilation for building cooling in Changsha city, China

As a passive cooling strategy, natural ventilation is an energy conservation technology with great developing potential. The typical technologies of natural ventilation include night ventilation and natural ventilation with heat storing materials. The factors which affect ventilation include technique parameter, climate parameter and building’s parameter. The natural ventilation in summer in a typical building in Changsha City, which locates in hot summer and cold winter area, was measured.

A mathematical model for a house integrated with an elevated Chinese Kang heating system

Chinese kang, a potentially energy-efficient domestic heating system in China, uses high thermal mass to store surplus heat from the stove during cooking and releases it later for space heating. In this paper a preliminary mathematical model is developed for a House Integrated with an Elevated Kang system (HIEK). This model considers the transient thermal behaviors of building envelope, kang system and indoor air. The macroscopic approach is used to model the thermal and airflow process for the elevated kang system.

Natural ventilation in hospital wards of semi-arid climates: a case for acceptable indoor air quality and patients’ health

Owing to the growing concern about indoor air quality (IAQ) globally in hospitals, especially after the recent outbreak of diseases like severe acute respiratory syndrome (SARS), Swine Flu (H1N1) and other airborne infections such as Tuberculosis, the quest for energy efficient ventilation system is growing. To provide acceptable indoor air quality that is capable of removing indoor air contaminants in hospital wards, sustainable ventilation strategy is required.

Double-skin system of room-side air gap applied to detached house (Part 2): Simulation analysis to reduce cooling load through natural ventilation in wall

In Japan, wooden detached residential houses are common; the wood components within a wall may undergo decay because of condensation in the wall or flushing defects, which can be a concern. The temperature distribution throughout the house, such as a high temperature in the attic space, can cause discomfort to the occupants. A double-skin system of room-side air gaps is considered to be an effective technique to handle these problems.