A significant portion of the total primary energy is consumed by today's buildings in developed countries In many of these buildings, the energy consumption can be significantly reduced by adopting energy efficiency strategies Due to environmental concerns and the high cost of energy in recent years there has been a renewed interest in building energy efficiency This article strives to make an exhaustive technical review of the building envelope components and respective improvements from an energy efficiency perspective Different types of energy efficient walls such as Trombe walls, ventilated walls, and glazed walls are discussed Performance of different fenestration technologies including aerogel, vacuum glazing and frames are presented Advances in energy efficient roofs including the contemporary green roofs, photovoltaic roofs, radiant-transmittive barrier and evaporative roof cooling systems are discussed Various types of thermal insulation materials are enumerated along with selection criteria of these materials The effects of thermal mass and phase change material on building cooling/heating loads and peak loads are discussed Application of thermal mass as an energy saving method is more effective in places where the outside ambient air temperature differences between the days and nights are high Air tightness and infiltration of building envelopes are discussed as they play a crucial role in the energy consumption of a building Energy efficiency approaches sometimes might not require additional capital investment For example, a holistic energy efficient building design approach can reduce the size of mechanical systems compensating the additional cost of energy efficiency features

Passive building energy savings: A review of building envelope components

Odor plumes and how insects use them , Odor plumes and how insects use them , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

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Odor plumes and how insects use them

Natural ventilation of buildings is the flow generated by temperature differences and by the wind. The governing feature of this flow is the exchange between an interior space and the external ambient. Although the wind may often appear to be the dominant driving mechanism, in many circumstances temperature variations play a controlling feature on the ventilation since the directional buoyancy force has a large influence on the flow patterns within the space and on the nature of the exchange with the outside. Two forms of ventilation are discussed: mixing ventilation, in which the interior is at an approximately uniform temperature, and displacement ventilation, where there is strong internal stratification. The dynamics of these buoyancy-driven flows are considered, and the effects of wind on them are examined. The aim behind this work is to give designers rules and intuition on how air moves within a building; the research reveals a fascinating branch of fluid mechanics.

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The fluid mechanics of natural ventilation

Factors involved in the aerosol transmission of infection and control of ventilation in healthcare premises

Explicit algebraic equations for calculation of wind and stack driven ventilation were developed by parametrically matching exact solutions to the flow equations for building envelopes. These separate wind and stack effect flow calculation procedures were incorporated in a simple natural ventilation model, AIM-2, with empirical functions for superposition of wind and stack effect and for estimating wind shelter. The major improvements over previous simplified ventilation calculations are: a power law pressureflow relationship is used to develop the flow equations form first principles, the furnace or fireplace flue is included as a separate leakage site and the model differentiates between houses with basements (or slab-on-grade) and crawlspaces. Over 3400 hours of measured ventilation rates from the test houses at the Alberta Home Heating Research Facility were used to validate the predictions of ventilation rates and to compare the AIM-2 predictions to those of other ventilation models. The AIM-2 model had bias and scatter errors of less than 15% for wind-dominated ventilation, and less than 7% for buoyancy ("stack-effect") dominated cases.

Field Validation of Algebraic Equations for Stack and Wind Driven Air Infiltration Calculations

https://escholarship.org/content/qt16q0h8cz/qt16q0h8cz.pdf?t=p21n17

A comparison of the power law to quadratic formulations for air infiltration calculations

https://escholarship.org/content/qt319030c7/qt319030c7.pdf?t=p0fv1w

David J. Wilson

Papers

Field Validation of Algebraic Equations for Stack and Wind Driven Air Infiltration Calculations

A comparison of the power law to quadratic formulations for air infiltration calculations

Relating actual and effective ventilation in determining indoor air quality

Turbulent wall jets with cylindrical streamwise surface curvature

Gravity driven counterflow through an open door in a sealed room