Ten questions about natural ventilation of non-domestic buildings

Abstract

Throughout history, natural ventilation has remained the preferred choice for the majority of residential buildings, while, in commercial buildings, natural ventilation went from being the single option to somewhat of a lost art as mechanical ventilation systems and air conditioning became the standard during the second half of the twentieth century. Recently, as a result of environmental concerns, in particular the greenhouse gas emissions from buildings, interest in natural ventilation in commercial buildings has seen a resurgence. Unfortunately, the hiatus in natural ventilation use in these buildings has resulted in the loss of existing design know-how and consequently limited new developments in a period during which comfort and indoor air quality performance standards have continuously risen. Nevertheless, the past 25 years has seen significant advances in our understanding of the fluid mechanics of natural ventilation and Architectural Fluid Mechanics has developed as a new subject. In response to these new scientific advances and in an attempt to restore confidence in the applicability of natural ventilation in practice, this paper presents ten questions concerning building natural ventilation that span the different scales of the problem, from an urban context down to the neighbourhood and the building itself. These questions are commonly asked when a designer is considering natural ventilation as the preferred means of cooling a non-domestic building, and the answers are intended to provide succinct links to the latest knowledge, identify areas that require additional research and assist designers in making appropriate decisions.

Calculation methods for single-sided natural ventilation: Now and ahead

“…Ventilative cooling has shown to reduce energy demand for cooling or overheating risk in new and refurbished buildings through examples of well documented case studies that use ventilative cooling [5]. A successful natural ventilative cooling system can decrease office building energy consumption for cooling by 50%, indicating the relevance of ventilative cooling systems [6].…”

“…From fitting the constants to the measurements made by De Gids & Phaff, the values in equation (6) are found [9]:…”

Heat and Air Flow Behavior of Naturally Ventilated Offices in a Mediterranean Climate

“…Naturally ventilated buildings should integrate window to wall ratios, orientation, glazing properties, and visual and thermal comfort ideas that are designed properly in an architectural sense to maximize efficiency [14]. Since historical times, natural ventilation strategies have been chosen and used in all types of buildings; however, they have lost their popularity within the 20th century because of the standard use of mechanical systems in buildings [15]. It is important in sustainable architectural design to minimize the size of equipment that is needed in order to save energy through an optimal design, to maximize the use of natural energy, and to ensure the high performance of HVAC systems [16].…”

Numerical Studies of Turbulence Effects in Cross-Flow Ventilation

“…Since the second half of the 20th century, the majority of non-domestic buildings in most developed countries use mechanical ventilation (MV) due to increasing user expectations of thermal comfort and indoor air quality standards [1]. Heating, ventilation and air conditioning (HVAC) systems account for 40%-60% of total building energy consumption [2,3].…”

“…However, since the introduction of central heating and cooling, most buildings have been constructed to only use mechanical ventilation, and natural ventilation has been neglected [1]. There is therefore a need to identify how existing structures might perform with natural ventilation and to identify possible retrofitting strategies to improve airflow.…”