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Themal Comfort Presentation.
Sunrise and Sunset:
The yellow section shows when the sun is up, and how this changes over the year.
The sunrise and sunset times shown in the chart are approximate.
They are accurate for the latitude, and show the precise amount of daylight.
The charts are made assuming that the location is in the middle of an evenly spaced time zone.
 For Lahore City, Pakistan, use latitude 31°33'N and longitude 074°20'E in the form. You'll need to know the time zone of the location.
CHARACTERISTICS OF CLIMATE OF LAHORE:Hot & Dry
This type of weather is found in the months of March & April.
The air is dry, sky is clear and with no sea breeze to check the advance of the excessive heat.
The maximum temperature in mid March reaches 90 F and by the middle of April temperatures up to 100 F can be expected.
Due to clear atmosphere, nights however are cool with average temperature around 65 F.
Very Hot and Dry
110 F The heat is oppressive, humidity very low with very hot and dry wind locally called loo blowing most of the time.
June is still hotter with the high sometimes reaching to 119 F.
However in June due to intense low pressure created by the excessive heat, sometimes a little moisture from Arabian Sea finds its way to this area and causes thundershowers.
Hot and Wet
The months of July to September bring rains from the Bay of Bengal which after traveling about 100 km over India reaches Pakistan and enter Lahore from the South-East.
This rain system is called Monsoons.
Although the temperature comes down considerably from about 106 F just before the monsoons hits Lahore to about 95 F.
At times the rain falls with such a deluge that it inundates low lying area and people have to suffer great hardships So monsoon is a mixed blessing.
Warm and Dry
October and November.
Since the rain cease by about last week of September, the weather becomes dry again but this time it is not so hot.
The dry continental air prevails over the region.
The days are moderate to warm and nights are cool.
The average high temperature is about 85 F and at night due to dry air temperatures can fall to 53 F especially in late October or early November.
There is practically no rain.
Dryness gives rise to general dustiness and haziness
This is the reason that this season is responsible for the most incidences of common cold and other allergies.
Cool and Dry
December, January and February.
The highs are around 68 F (20 C) and the lows around 41 F (6 C).
The weather is cool, pleasant and very sunny.
Occasionally, western disturbance- a rain bearing system which has its source in Mediterranean Sea affects this part of the country and causes some rain.
December has one rainy day each year and January and February both have two rain days each year.
In short, the climate of Lahore is hot and dry for most part of the year with a brief winter period with very pleasant temperatures.
BUILDING DETAILS:
Old Building : Syeed Wajid Ali Shah’s Haveli
Location : Mochi Gate walled city lahore
Built In : 700 years ago
Area : 4 Kanal
INTRODUCTION TO HOUSE
This house is a pre-partition house.
It was built by the great grand fathers of syed wajid ali shah.
Mr. wajid has made a few changes in the building such as, some windows, doors, clerestory windows are permanently been closed.
There are certain rooms containing old furniture. these rooms remain close usually as nobody uses them.
PERCEPTION OF THERMAL COMFORT Dry bulb air temperature
Temperature is the most commonly quoted factor in relation to thermal comfort.
In this building, the air temperature is within reasonable limits, it is likely that there is a reasonable degree of thermal comfort.
This simple relationship between air temperature and comfort is less reliable in modern developments that make greater use of building thermal mass and employ active methods of heating, cooling and air supply.
Moisture content
There is a wide band of moisture conditions that does not provide a feeling of discomfort.
The heat loss from the body as a result of evaporation acts to balance the body’s equilibrium when the other means of heat transfer (convection and radiation) are insufficient.
When temperatures rise above the limit of 22°C, the relative humidity should be reduced ideally.
It is not possible to be precise as to the depression in relative humidity that should be employed, but with reference to various comfort indices, a reduction of 4% per degree over 22°C would seem appropriate.
ADAPTIVE COMFORT
The resurgence in the use of naturally ventilated and mixed mode building designs has increased interest in how occupants adapt to conditions – allowing more flexible, but still comfortable conditions.
MASSIVE WALLS AND AIR SEALING
Because the air inside a home is usually cooled or heated, the indoor temperature rarely matches the outdoor temperature.
Massive/thick walls are the solution to this issue in this house, helping to slow heat transfer between the home and the outdoors in order to maintain a comfortable indoor temperature.
The walls of this house are 22.5inches thick.
Just as important as insulation, air sealing of such massive walls lends to thermal comfort by preventing air from leaking through cracks, gaps, and porous materials in the home.
If a home doesn't have adequate air sealing, the HVAC system is forced to work harder to replace the
Height
Heights of living rooms, like drawing room, bedrooms, etc are 14’ high. Whereas store room and Imam bargha’s height is 7’.
The rooms have double height space for better ventilation. As the warm air rises up and the cool air provide thermal comfort
Thermal properties of this house
Facilitate quality IEQ (indoor environmental quality) through good design, construction, and operating and maintenance practices;
Value aesthetic decisions, such as the importance of views and the integration of natural and man-made elements
Thermal comfort with a maximum degree of personal control over temperature and airflow; is provided
Adequate levels of ventilation and outside air to ensure indoor air quality; is supplied
Airborne bacteria, mold, and other fungi through heating, ventilating, air-conditioning (HVAC) system designs that are effective at controlling indoor is prevented
Humidity, and building envelope design that prevents the intrusion of moisture
The use of materials high in pollutants, such as volatile organic compounds (VOCs) or toxins; is avoided
Assurance of acoustic privacy and comfort through the use of sound absorbing material and equipment isolation
Control disturbing odors through contaminant isolation and careful selection of cleaning products;
This creates a high performance luminous environment through the careful integration of natural and artificial light sources.
NATURAL VENTILATION SYSTEMS
The specific approach and design of natural ventilation systems is based on building type and local climate.
However, the amount of ventilation is dependent critically on the careful design of internal spaces, and the size and placement of openings in the building.
Maximized wind-induced ventilation by siting the ridge of a building perpendicular to the summer winds.
Approximate wind directions are summarized in seasonal "wind rose" diagrams available
NATURAL VENTILATION EFFECTS
Wind can blow air through openings in the wall on the windward side of the building, and suck air out of openings on the leeward side and the roof.
Temperature differences between warm air inside and cool air outside can cause the air in the room to rise and exit at the ceiling or ridge, and enter via lower openings in the wall.
Similarly, buoyancy caused by differences in humidity can allow a pressurized column of dense, evaporatively cooled air to supply a space, and lighter, warmer, humid air to exhaust near the top.
CROSS VENTILATION
Each room has two separate supply and exhaust openings.
Exhausts/clerestory windows (a.k.a “roshan daan”) are located high above inlet to maximize stack effect.
Orientation of windows across the room and offset from each other are to maximize mixing within the room while minimizing the obstructions to airflow within the room.
Window openings are operable by the occupants.
In the case of cross-ventilation, (windows open on both sides of the room/building) the pressure difference is used between the side of the building facing the wind and the side away from the wind. The positive pressure on the windward and/or a vacuum effect on the lee side of the building cause air movement through the building from the windward to the lee side.In order to obtain the optimal airflow with minimal draught, the windows on the windward side are opened less than on the lee side.
CONSIDERED THE USE OF CLERESTORIES OR VENTED SKYLIGHTS
The clerestories or vented skylights provide an opening for stale air to escape in a buoyancy ventilation strategy.
The light well of the skylight c also act as a solar chimney to augment the flow.
Openings lower in the structure, are provided to complete the ventilation system
CONSIDERED THE USE OF FAN-ASSISTED COOLING STRATEGIES
Ceiling and whole-building fans can provide up to 9°F effective temperature drop at one tenth the electrical energy consumption of mechanical air-conditioning systems
MECHANICAL COOLING
Mechanical cooling is also used as it is compulsory in hot, humid climates.
Natural ventilation in Lahore’s climates will not move interior conditions into the comfort zone 100% of the time. Make sure the building occupants understand that 3% to 5% of the time thermal comfort may not be achieved.
This makes natural ventilation most appropriate for buildings where space conditioning is not expected as in this house.
As a designer it is important to understand the challenge of simultaneously designing for natural ventilation and mechanical cooling
MATERIALS AND METHODS OF CONSTRUCTION
Some of the materials and methods used to design proper natural ventilation systems in buildings are solar chimneys, wind towers, and summer ventilation control methods.
A solar chimney which is made in this building is an effective solution when prevailing breezes are not dependable enough to rely on wind-induced ventilation and when keeping indoor temperature sufficiently above outdoor temperature to drive buoyant flow would be unacceptably warm.
The chimney is isolated from the occupied space and can be heated as much as possible by the sun or other means.
Air is simply exhausted out the top of the chimney creating suction at the bottom which is used to extract stale air.
SCREENING SYSTEM
Roller Window Shades
Roller shades, also called roll up shades or roller blinds, are an easy and economical way to add color, style and texture to any decor.
A Roll Shade custom window coverings are premier choice for solar protection.
Simple, modern and cost-effective solutions for any location.
Simply pull the cord, not the fabric, to position the shade at the perfect height!
INDOOR AIR QUALITY
Indoor air quality is closely related to ventilation.
Fresh outdoor air replaces indoor air through ventilation, thus removing and diluting contaminants generated indoors.
The air well encourages the development of high performance controlled ventilation to maintain adequate air quality while reducing energy consumption.
WINDOW AND DOOR SHADES
Shades are for blocking solar rays and heat coming inward.
Depending on the orientation of the building only horizontal shades are used to protect from high angle sun.
As in winters low angle sun radiations are useful for heat gain that is why vertical shades are not given.
The projection of the overhang that will be adequate (provide 100% shading at noon on June 21) at particular latitudes can be quickly calculated by using the following formula:
Projection = window opening (height)/ F (see Table)
DIRECT GAIN
The simplest of approaches is a direct gain design.
Sunlight is admitted to the space (by south facing glass) and virtually all of it is converted to thermal energy.
The walls and floor are used for solar collection and thermal storage by intercepting radiation directly, and/or by absorbing reflected or reradiated energy.
Direct gain design is simple in concept and can employ a wide variety of materials and combinations of ideas that will depend greatly upon the site and topography; building location and orientation; building shape (depth, length, and volume); and space use.
The pictures shows that one side of the house (the left picture) is not exposed to sun but the other side (right picture shows) sun exposed, a tree has been planted to stop solar gain and to provide cool shade of leaves.
PASSIVE SOLAR HEATING/COOLING
Passive Solar Heating presents the most cost effective means of providing heat to buildings.
Generally, the amount of solar energy that falls on the roof of a house is more than the total energy consumed within the house.
Passive solar applications, when included in initial building design, adds little or nothing to the cost of a building, yet has the effect of realizing a reduction in operational costs and reduced equipment demand.
ENTRYWAYS / INFILTRATION
Entries account for great deal of heat loss/gain especially in small structures.
Heat is lost/gain during opening and closing of doors (or windows). Heat can also be lost/gain by seeping between the doorframe and the door, and at windows.
This kind of window, door or other wall penetration heat loss (or heat gain in the summer) is called infiltration.
To reduce both direct and infiltration losses, entryways should be recessed or protected against the direct force of prevailing winds.
This double entry, or vestibule, creates a tempered zone between the outside elements and the interior living space thereby reducing the amount of warm air lost (and summer heat gained).
The wooden doors and windows are made in such a way that when they are closed they do not infiltration occur.
WINDOWS
The major expanse of windows in this structure is south facing solar windows.
Whole design planning includes considerations re: the impact of heat gain in the summer; views; natural lighting; and privacy requirements in determining the placement and size of windows in the structure.
For the most part, window areas on east, west and north facing walls are kept as small and as minimal as is consistent with interior requirements.
Windows are the least effective heat flow inhibitors of a building's shell, both in terms of letting heat out in the winter, and letting heat in the summer.
MASONRY
The major concern in designing a structure to avoid uncomfortable temperature fluctuations over the day-night cycle.
It is relatively easy to calculate the amount of heat that will be admitted to a room by any particular collecting surface.
About 65 percent of all heat gained through solar windows during a clear winter day can be lost during the night and vice versa in summers.
This means that during the day, 65 percent of the heat gained must be stored to offset nighttime losses, and to maintain a relatively even temperature profile.
Furthermore, efficient storage during the day prevents the build-up of heat during daylight hours.
In general terms, the following rules should be observed in regard to design of moderate systems:
* Masonry and concrete floors, walls and ceilings to be used should be a minimum of 4 inches thick.
* Sunlight should be distributed over as much of the storage mass surface as possible by using translucent glazing.
* A number of small windows to admit sunlight in patches give better control re: overheating.
* Use light colored surfaces (non-thermal mass storage walls, ceilings, floors) to reflect sunlight to thermal storage mass elements.
* Thermal storage mass elements (floors, walls, ceilings) should b dark in color.
* Masonry floors used for thermal mass should not be covered with wall-to-wall carpeting.
* Direct sunlight should not hit dark colored masonry for long periods of time.
WALL DETAILS
Aside from the wall area and amount of exposure, the thickness, type of material, and exposed surface color of a wall are main considerations that determine the effectiveness of a wall in meeting the thermal needs of the structure's occupants.
As according to Lahore’s climate we cater summers and use lights, but this house’s exterior walls were un-painted and were just cemented. Whereas interior walls are light in color.
Such sculptures were found in these hollows
PERFORATED WALL
It is boundary between inside and outside .this can be designed as a only form of enclosure or a secondary element built in front of the line of enclosure.
Its function is like recessed glazing.
The main aim is to break the direct force of the sun. In this way less amount of sunlight will penetrate.
“Jail” is the term used for perforated stone or latticed screen, usually with an ornamental pattern constructed through geometry.
This is a common element of Indian architecture.
It also acts as a vision panel providing a view to both inside and outside.
THE STAIRS ARE VENTILATED AND DAYLIGHTENING IS ALSO PROVIDED
COURTYARDS CAN BE “U””L””4 SIDED”
Fully Closed.
Semi Open Courtyard.
Semi Closed.