1 / 12

Passive cooling techniques

This presentation will help you to learn passive cooling techniques

anas1
Download Presentation

Passive cooling techniques

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Passive cooling techniques Presented by: Muhammad Anas Ilyas

  2. What is passive cooling: • A passive cooling involves the use of natural processes for cooling to achieve balanced interior conditions. • The flow of energy in passive design is by natural means radiation, conduction, or convection without using any electrical device.

  3. Why passive cooling: • THE CURRENT ELECTRICITY SHORTFALL HAS CROSSED THE EDGE OF 6000 MW AS COUNTRY RURAL AND URBAN AREAS ARE FACING 14 AND 10 HOURS ELECTRICITY LOAD-SHEDDING RESPECTIVELY. (JULY 02, 2018 THE NATION) • ENERGY PRODUCING MECHANICS ARE RESPONSIBLE FOR GREEN HOUSE GAS EMISSIONS WHICH ARE NOT GOOD FOR THE ENVIRONMENT

  4. passive cooling Techniques: These design strategies reduce heat gains to internal spaces: • Natural ventilation • Earth tunnels • Evaporating cooling • Shading • Wind tower • Steering breeze • Cross ventilation

  5. Natural ventilation: • Outdoor breezes create air movement through the house interior by the push-pull effect of positive air pressure on the windward side and negative pressure (suction) on the leeward side • In order to have a good natural ventilation, openings must be placed at opposite pressure zones. • Also, designers often choose to enhance natural ventilation using tall spaces called stacks In buildings.

  6. Earth tunnels: • Daily and annual temperature fluctuations decrease with the increase in depth below the ground surface. • At a depth of about 12-13 ftbelow ground, the temperature inside the earth remains nearly constant round the year and is nearly equal to the annual average temperature of the place. • A tunnel in the form of a pipe or otherwise embedded at a depth of about 12-13 ft below the ground will acquire the same temperature as the surrounding earth at its surface. • Therefore, the ambient air ventilated through this tunnel will get cooled in summer and warmed in winter and this air can be used for cooling in summer and heating in winter.

  7. Evaporating cooling: • Evaporative cooling lowers indoor air temperature by evaporating water. • It Is effective in hot and dry climate where the atmospheric humidity Is low. • In evaporative cooling, the sensible heat of air is used to evaporate water, thereby cooling the air, which, In turn, cools the living space of the building. • Increase in contact between water and air increases the rate of evaporation. • The presence of a water body such as a pond, lake, and sea near the building or a fountain In a courtyard can provide a cooling effect.

  8. Shading: • Solar control Is a critical requirement for both cooling-load dominated and passively solar-heated buildings. • The most effective method of cooling a building is to shade windows, walls and roof of building from direct solar radiation. • Heavily insulated walls and roofs need less shading. • Can use overhangs on outside facade of the building. • Each project should be evaluated depending on Its relative cooling needs. • Extend the overhang beyond the sides of the window to prevent solar gain from the side. • Use slatted or louvered shades to allow more daylight to enter, while shading windows from direct sunlight. • Reduce solar heat gain by recessing windows into the wall.

  9. Wind tower: • In a wind tower, the hot air enters the tower through the openings in the tower, gets cooled, and thus becomes heavier and sinks down. • The inlet and outlet of rooms Induce cool air movement. • In the presence of wind, air is cooled more effectively and flows faster down the tower and Into the living area. • After a whole day of air exchanges, the tower becomes warm in the evenings. • During the night, cooler ambient air comes in contact with the bottom of the tower through the rooms.

  10. Steering breezes (Natural ventilation): • Not all parts of buildings can be oriented for cross-ventilation. But wind can be steered by architectural features, such as casement windows, wing walls, fences, or even strategically-planted vegetation. • Architectural features can scoop air into a room. Such structures facing opposite directions on opposite walls can heighten this effect. These features can range from casement windows or baffles to large-scale structures such as fences, walls, or hedgerows.

  11. Cross ventilation (Natural ventilation): • WINDOWS OR VENTS PLACED ON OPPOSITE SIDES OF THE BUILDING GIVE NATURAL BREEZES A PATHWAY THROUGH THE STRUCTURE.

  12. Scope: • TO MINIMIZE THE EXTERNAL ENERGY OR MECHANICAL SYSTEM. • IMPLEMENTATION OF NATURAL VENTILATION SYSTEM- NATURAL DAYLIGHTING CAN BE PROVIDED. • THERMAL COMFORT CAN BE ACQUIRED WITH LESS ECONOMICAL BUDGET

More Related