Climate Of Lahore And Thermal Comfort Environmental Sciences Essay

modality Of Lahore And Thermal Comfort Environmental Sciences tasteChapter 22.1 IntroductionClimate has great government issue on build for its electri city consumption and create performance. Energy efficient design requires the love of the mood. The e trulyplaceall erupting forming and engine cooling system requirements in the buildings is controlled by clime during pass and winter placate. As we have selected our state of affairs in Kala Shah Kaku, Punjab and kala shah kaku is located in Lahore function in that respectfore the description of the climatical data of Lahore region is pre designer be piteous.2.2 Climatic classificationClimate cig atomic number 18t be classified in ground building design in which the country will be change integrity into five regularizes in such a way that the inequality of climate from zone to zone can be seen in the building design, gauranting more or less special provision for each zone. Based on these criteria, thither a r five major climatic zones, anxious- ironic impatient-humidColdTemperate multiformTypes of climate Typical CharacteristicsCold Excessive heat loss for some of the yearMinimum Temperature infra -15 CTemperate Excessive heat lost for damp of yearInadequate heat loss for part of yearTemperature changes -30 C to 30 CHot/Dry overheat for close part of the yearDry nervous st rainfall allow vaporizationTemperature ranges -10 C to 45 CHigh radiationStrong WindsHot/Humid Overheating for about of yearHumid conduct inhibits coolingTemperature often above 20 CMean relative humidity around 80 %High rain in certain months hold over 2.1 typical signs of different types of climates2.3 Climatic zones of PakistanPakistan has a wide range of climatic conditions. The Northern and North- Western parts of Pakistan are cooler, the centre of the Punjab is totally keen and semi-arid, and the Baluchistan is cool and arid whereas the coastal strip is prompt and humid. In wintry regions, durin g the winter temperature drops well below the zero. In the desert regions, the level best temperature corpse above 40C during more or less of the summer end with a peak often approaching 50C.The climatic regions have been divided based on various criteria.Fig 2.1 map of climatic zones of Pakistan2.4 Climate of Lahore RegionLahore lies 217 meters above sea level and it lies between 3115 and 3145 North latitude and 741 and 7439 East longitude. On the North and West Lahore is bounded by Sheikhupura district, Wagah surrounds Lahore on east, and on the south of Lahore there is Kasur District. The river Ravi flows on the North of Lahore. Lahore city has a total land area of 404km2.The Lahore region comes under the blueprint compo rate zone, according to climatic zone map. It lies near the het up ironic zone and in summer the twisting direction is such that the wind blows northeast towards southwest of the city affecting the climate of Lahore region. The effect of sweltry alter zo ne starts from March and remains till September as the wind direction is southwest which means from importunate alter zone towards Lahore region. The main features of this season are that the winds blown are hot and adept of ashes during the daytime but are cooler in night. blockade-to-end the day very strong wind blows. The climate of Lahore region can be divided into the following broad categories2.4.1 Hot and dryHot and dry live is found in the months of March and April. In these months the air is dry with the pinch sky and no sea breeze to fancy the excessive heat as the Lahore region is located more(prenominal) than kibibyte km from the nearest sea, the temperature rise is sharp. In the mid-March the maximum temperature reaches up to 90 F and till the middle of April temperatures reaches up to 100 F. Due to clear sky, nights are cooler having the second-rate temperature of al some 65 F (18 C). The rainwater is very less in this duration.2.4.2 Very hot and dryIn t he months of May and June the weather of Lahore is very hot and dry and the heat is at its peak in these months. In the second week of May, the temperature reaches up to cx F (43 C).The heat is oppressive, humidity level is low with very hot and dry wind which is called loo in local language blowing most of the time. The month of June still remains hotter with the temperature sometimes reaching to 119 F (48 C). that in June due to intense low pressure created by the extreme heat, sometimes some moisture from Arabian Sea finds its way to this region and causes rain which for the brings the temperature down temporarily.2.4.3 Hot and wetThe months of July to September are rainy. Monson clouds go from the Bay of Bengal and after traveling intimately 100 km over India reaches Pakistan and enter Lahore from the South- East. This rain system in these months called Monsoons. This is a regular characteristic of the Punjab, in this country. The weather is cool and pleasant when it rains, otherwise hot and humid. Although the temperature decreases significantly, from nearly 106 F ( 41 C ) just before the monsoons starts in Lahore to about 95 F ( 35 C ) but as the monsoon arrives there is the increase in the relative humidity which increases from less than 25% to more than 65%. The mellow temperature along with the excessive humidity makes the weather very exhausting. Moreover sometimes the rain move with such an avalanche that it drowns the low lying area and people have to undergo great hardships so this weather is a mixed blessing.2.4.4 Warm and dryWarm and dry weather remains in the months of October and November. Since the monsoon stops at the end of September, the weather again becomes dry again but the temperature is considerably less hot this time. The dry continental air remains in the region. The temperature is moderate to spry during days whereas the weather is cooler in nights. The average high temperature is nearly 85 F (29 C) and at night due to dry air temperatures it can decrease to 53 F (12 C) especially at the end of October or early November. There is no rain in this season and this season is the driest season as compared to other seasons. This extreme dryness creates a lot of dust and haziness which results in pollution in the milieu.2.4.5 chill and dryThe most pleasant months of all are December January February in Lahore. This is the most perfect weather of Lahore. The peak high temperature is nearly 68 F (20 C) and the peak low temperature is nearly 41 F (6 C). The climate remains cool, refreshing and sunny. However sometimes, a rain bearing system known as western disturbance which has its source in Mediterranean Sea affects the Lahore region and causes rain. But the rain is not so strong neither it remains for a long duration. So the weather most of the times remains sunny, dry and refreshing.In fact, the climate of Lahore is hot and dry for the maximum period of the year with a short winter period with very refre shing weather.2.5 Climatic indicators of LahoreThe table below displays average periodic climate indicators in Lahore which is based on 8 years of diachronic weather readings.Temperature in FahrenheitTable 2.2 average monthly climate indicators in Lahore2.6 Hot dry climateThe hot dry equatorial land lying between the two mean annual isotherms of 68F (20C) has regions where the temperature during the summer season may reach 43.3C or may exceed and the vapor pressure is below 25millibars.2.6.1 Elements of hot dry climate1 Seasonal transmutation2 var. temperature3 Humidity4 Precipitation5 Wind6 gear conditions and solar radiation7 Dust storm2.6.1.1 Seasonal variationIn these regions there are two major seasonshot seasonwinterFig 3.2 Monthly averages of the minimum and maximum daily temperatures.C/F2.6.1.2 Air temperatureThe main features of the climate are temperature remains high during the day 80-130F (26.67-54.44C) in the summer months along with strong sunniness reflecting pi tilessly from light dry and parched earth.There is however a big difference between summer and winter temperatures due to the variable altitude of sun. During winter the day temperature is usually as high as 90F (32.22C) but the temperature is quite low at nights ,whereas during summer the temperature goes down to 50F(10C) compared with 70F (21.11C) at night.2.6.1.3 HumidityHumidity remains low, copulation humidity varies with the air temperature. It can go below 20% in evening to over 40% at night. V.P fairly steady ever-changing with location and season from about 500-1500 N/m22.6.1.4 PrecipitationThe essence of rainfall or precipitation is generally noted as the average mm/day or mm/month which provides a beneficial recitation regarding seasonal changes.Usually, average maximum rainfall in 24 hours or the average number of days in which a certain amount (in cm.) of rainfall happened is similarly stipulation. This data is beneficial as an indicator of the rain intensity, wh ich will affect the design of windows, roofs and sewerage etc.July and August are the months in which most rainfall materialise, whereas June and September also have some rainy days. For the rest of the year, hardly any rain fall occurs in Lahore. Based on temperatures and precipitation data, during the hot and rainy season it is not advised to go between June and September. The rest of the year is dry with cold-temperate daytime temperatures.Fig 3.3 Precipitation is any kind of water that falls from the sky as part of the weather.2.6.1.5 Sky conditions and solar radiationsThe skies are without clouds for the most of the period of the year where as frequent dust haze and storms occur mostly in the good afternoon. Direct solar radiation is severe and is amplified by radiation reflected from the barren and light colored landscape.Fig 3.4 Monthly average numbers of hours of sunshine per day.2.6.1.6 WindWinds are mostly native they are generally low in the morning however increasing to wards afternoon and are maximum in the afternoon, most commonly accompanied by whirlwinds of dust and sand.2.6.1.7 Dust stormsDust storms mostly occurs on summer afternoons which is the most intolerable part of the day , when routine winds blow at 15-220 miles per hour. These dust storms also occurs in other parts of the day i.e. in the evening and nights.2.7 Climatic design of buildingClimate has a great effect on building performance and electricity consumption of the building. The process of recognizing, deducing and arrogant climatic effects at the building is perhaps the most strong part of building design. The main objectives of climatic design of building should let inTo minimize electricity cost of a building.To take benefit of maximum of natural energy instead of mechanical system and electricity.To provide soft and healthy environment for inhabitants.2.8 Factors affecting climatic designThe native micro-climate and site brokers influence the actual environmental condit ions of the building. Some important factors related to site should be included while making the climatic analysisTopography- elevation, slopes, hills and valleys, free-base advance conditions.Vegetations height, mass, silhouette, texture, location, growth patterns.Built forms nearby buildings, surface conditionsImportant caloric design factors which should be considered include solar heat gain, conduction heat flow and ventilation heat flow. The design variables in architectural terms which are important to be considered areShape surface-to-volume ratio orientation building height.Building fabric materials and construction thermic insulation surface qualities shading and sun control.Fenestration the size, position and orientation of windows window glass materials away and internal shading devicesVentilation air-tightness outdoor fresh air intersection ventilation and natural ventilation.2.9 Thermal pouffeThere is no ratified standard for thermal comfort. This is not a stonishing, as people can and do live in a wide range of climates from the equator to high latitudes. An Internationally- evaluate definition of thermal comfort, used by ASHRAE, is that condition of mind which expresses contentment with the thermal environment (ISO7330).Perceptions of this environment are influenced by air temperature, radiant temperature, relative humidity, air velocity, activity and clothing.Fig 3.5 achieving comfort in buildings2.9.1 The comfort zoneThe Comfort Zone means the range of temperature conditions of air movement, humidity and exposure to direct radiations, under which a normally clothed somebody feels comfortable. This will differ for Indoor conditions as compared to Outdoor conditions. This will also vary for different cultures and regions and varying climate conditions.As an Architects we use our buildings to not only create comfortable inside environments, but also aesthetic and beneficial spaces outside our buildings.2.9.2 Thermal comfort indexA thermal comfort index serves the objective to evaluate the effect of environmental factor on the thermal feeling of inhabitants. Number of methods have been used in the previously to evaluate the thermal comfort level. However it is not potential to gratify every person in a building and a small number of persons are always discontented with the thermal environment due to individual variations. Several efforts have been made to produce a subjective and quantitative way of representing the thermal comfort.Thermal comfort condition in tropical summer conditions is given by Sharma and All at the Central Building Research Institute, Roorkee, India. The ranges and optimum entertains are given in table.Thermal sensationRange COptimum value CSlightly cool19-2522Comfortable25-3027.5Slightly warm30-3432Table 3.3 temperature ranges in different thermal zones2.9.3 Optimal settings for indoor(prenominal) temperatureResearchers have carried out much research on the most fitted comfort condit ions, and have come up with general comfort results kindred effective warmth, the recent comfort standards set by ASHRAE (American society of heating, refrigerating and air condition engineers) for an individual performing light work areThermal comfort conditionsAir temperature 73-77 F Relative humidity below 60 %Mean radiant temp equal to air temperatureAir velocity 10-45 ft/min