WEATHER, SOLAR AND WIND ANALYSIS

Weather analysis : 

Weather analysis AMRITSAR SOLAR AND WIND ANALYSIS

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Latitude: 31.4’ Longitude: 74.5’ Altitude: 234m above sea level

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The two most important climatic factors that influence the thermal behavior of a building are air temperature and solar radiation. Solar radiation can cause severe overheating in summer (in some cases even in winter), or it can increase the air conditioning load, whilst it can be beneficial in winter, reducing the heating requirement or perhaps even eliminate the need for heating by using conventional forms of energy. One of the first tasks of a designer is to determine when solar heat input is desirable and when solar radiation is to be excluded. The next step will then be to provide the appropriate solar control. A prerequisite of designing the solar control is to know the sun’s position at any time of the year and then to relate it to the building.

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Shaded area showing temperature from month of January to June. Months of April, May and June shaded in yellow show maximum temperature that is 43ºC and above.

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Shaded area showing temperature from month of June to December. Average temperature even during winter seems to be above 20ºC

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Looking at graph we can conclude April, May and June to be hottest while from mid November to mid February coldest months.

Peak temperature days : 

Peak temperature days

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Optimum orientation based on location of city (northern hemisphere) and months (coldest and hottest).

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Annual Incident Solar Radiation based on best orientation. The aim here is to adjust the orientation such that you maximise solar collection in the three coolest months whilst at the same time minimising it for the three warmest.

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Green band shows the comfort zone. And blue graph shows the deviation from that zone

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Ventilation Ventilation of a building is critical during summer as the building must provide sufficient ventilation and breeze paths to assist with cooling. For warmer climates doors and windows should be positioned to facilitate prevailing cooling breezes. Locate windows and design systems to 'catch' or funnel the breezes through them.

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The wind frequency is the percentage of the time the wind is coming from a particular direction. This is useful to design windows and ventilators to bring the fresh air in and old air ventilate out.

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During summer and spring wind is coming from west. And in winter it is reverse.

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Wind direction at 3 pm and 9am is same, i-e from west.

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Wind rose diagram of 12 months.

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This diagram shows average temperature of wind coming from different directions.

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The upper left diagram shows wind, during summer, coming from north has higher temperature. Other three diagrams relates to the other seasons.

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During summer north wind is less humid and south west wind is most humid. East wind is more humid during winter.

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Points to consider are Locate the openings, windows and ventilators, to bring the fresh air in. Avoid high temperature air during summer and Also its important to avoid humid air during monsoon.

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Quick Review Following are the key point to be considered for Good passive design for thermal comfort: Orientation of frequently used areas towards the equator (south in the northern hemisphere), to allow maximum sunshine when it is needed for warmth, and to more easily exclude the sun's heat when it is not. Glazing used to trap the sun's warmth inside a space during winter, with adequate shading and protection of the building from unwanted heat gain or heat loss. Ventilation to provide fresh air and capture cooling breezes. Zoning of internal spaces to allow different thermal requirements to be compartmentalised when required.

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Psychometric chart shows comfort zone based on activity level. It combines different elements like dry bulb temperature, wet bulb temperature, absolute humidity, relative humidity to calculate comfort zone suitable for specific activity and seasons throughout the year.

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Upper graph shows total cooling degree hours and lower red graph shows total heating degree hours. Main emphasis is to be on cooling hours as shown in tables and graph.

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Yellow outlined regions show different zones. Black line with months initial written along the graph show average maximum temperature of each month.

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Different passive and active techniques that can be used to maintain comfort level in Amritsar.

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Overall ventilation is to be used in such climate.

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Different passive strategies available in weather tool representing increased comfort zone monthly and annually. As depicted in previous slides as well as in these charts ventilation (day n night) is most suitable.

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Comfort chart with Natural ventilation & expected mass +night purge ventilation design techniques. Chart shows comfort level reaches up to 70%.

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Comfort chart with Natural ventilation & thermal mass design techniques.

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Comfort chart with Natural ventilation, passive solar heating & expected mass +night purge ventilation design techniques.

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Ventilation and night purge ventilation increase the yellow comfort zone. Blue lines show monthly temperature ranges.

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Black line with months initial written along the graph show average maximum temperature of each month. Red outlined region show the increased comfort zone.

Techniques to be used : 

Techniques to be used We can use techniques suitable for hot and humid climate and as indicated by graphs and charts most suitable techniques are Day Ventilation Night purge ventilation Wind tower Another factor to keep in mind is to avoid sun in summer and invite it in winter. Solar chimney is possible.