BIOCLIMATIC ARCHITECTURE

BIO-CLIMATIC RESEARCH

[Company name]

ASSIGNMENT TWO | MARCH 12TH 2015

SOLAR RADIATION INTENSITIESBASED ON 34 EARTH LATITUDE NORTHS SUN-PATH DIAGRAM

INTRODUCTIONSun path diagrams are diagrams that show the path of the sun in relation to the Earth during the day. In the figure on the right hand, it shows how the sun's path changes during the year at Tucson, and it also demonstrates the sun's path at different locations on the globe. [footnoteRef:1] [1: http://www.atmo.arizona.edu/students/courselinks/fall07/nats101s31/lecture_notes/sunpaths.html]

The sun path varies with the latitude of the location, changing the exposure on the surface; the sun path below, represents the sun trajectory in Lebanon, at 34N Latitude.[footnoteRef:2] [2: primedesignpea.com/pdf/2005,_Climate_and_Comfort.pdf]

SOLAR RADIATIONS IN LEBANONThe amount of radiation obtained by structures is verified by their orientation towards the sun. The variation differences of solar radiation intensities between the different building facades of orientations and the horizontal surface are shown in the graph. [footnoteRef:3] [3: primedesignpea.com/pdf/2005,_Climate_and_Comfort.pdf]

GRAPH ANALYSISThe wall on south receives the next highest intensity in winter (when the Sun is low) but it receives very little in summer; this is because when the sun is low, the faade harvests more sun radiations (4.5 KWh/m2 per day). In Summer, the southern faade harvests less radiations (0.5 KWh/m2 per day), and the horizontal surfaces level increases to the maximum (8.0 KWh/m2 per day). On the spring (March / September), the south east and south west facades reach their maximum in harvesting solar radiations (3.3 KWh/m2 per day). As for the east and west facades reach their maximum in June (3.0 KWh/m2 per day). The northern faade has the lowest average regarding the ratio of radiation harvest (0.3 KWh/m2 per day). [footnoteRef:4] [4: Author Analysis]

For the horizontal surface, the intensity reaches a peak level of some 1 800 W/cm in June and decreases to its lowest level close to 500 W/cm2 in December. The higher range of values in excess of the annual mean of about 1 100 W/cm prevails from the spring equinox (22 March) to the autumn equinox (22 September). For the inclined target at any time of the day, the intensity prevailing in May-June was appreciably higher than in September-October.At noon in Beirut for instance, the Radiation intensity under average conditions should be about 19 W/m2 (1 900 W/cm2) in May-June, and about 17 W/m2 (1 700 W/cm2) in September-October on an inclined target.

CONCLUSIONSThe orientation away from the South would obtain the least sunshine throughout the day, but in the graph it shows that in Winter it is desirable to have some solar heat gain, when the sun is low, an orientation towards the Equator may be desirable.However, in summer, way more radiation falls on the horizontal surface than on the north face. This is due to the sun that is much higher in the sky, so that the incidence angle prefers the horizontal surface. The south part reaches its highest point in the evening and morning. [footnoteRef:5] [5: http://www.new-learn.info/packages/clear/thermal/buildings/configuration/building_orientation.html]

Figure: Different sun-path diagrams on extreme locations on earth

Figure: Sunpath of Lebanon, 34N Latitude. Figure: 3d sunpath diagram showing shadow variation during Winter (right), summer (Left)[footnoteRef:6] [6: primedesignpea.com/pdf/2005,_Climate_and_Comfort.pdf]

Figure: Variation of the Solar Radiations on Different facades in addition to the horizontall[footnoteRef:7] [7: http://www.new-learn.info/packages/clear/thermal/buildings/configuration/building_orientation.html]

Figure: Weekly values (solid line) and moving averages (broken line) for solar radiation intensity on a horizontal surface in Beirut from 28 January 1985 to 26 February 1986.[footnoteRef:8] [8: http://almashriq.hiof.no/lebanon/600/610/614/solar-water/idrc/10-19.html]

Figure: Weekly values (solid line) and moving averages (broken line) for solar UV-A radiation intensity on a vertical surface in Beirut from 28 January 1985 to 26 February 1986..[footnoteRef:9] [9: http://almashriq.hiof.no/lebanon/600/610/614/solar-water/idrc/10-19.html]

Figure: Effect of target orientation on the received solar UV-A radiation throughout the day in beirut (23 October 1985).

HARVEST DIRECT SOLAR RADIATIONSILLUSTRATE BY AN EXAMPLE SHOWING MATERIALS AND TECHNIQUES.INTRODUCTIONThe sun provides solar radiations or heat that can be used as energy through different passive solar design, solar space heating and electric generation, and solar hot water systems. [footnoteRef:10] [10: http://www.ext.colostate.edu/pubs/consumer/10624.html]

TECHNIQUE DESCRIPTIONOne technique is the photovoltaic cell which is a renewable source of energy that does not produce the greenhouse effect. Photovoltaic solar panels convert solar radiation or insolation into direct electricity (DC). Insolation is knows as watt per square meter when denoting to electrical generation. Photovoltaic solar systems are several panels connected together with an electrical disconnected. [footnoteRef:11] [11: http://www.ext.colostate.edu/pubs/consumer/10624.html]

GRAPH READINGOn a clear day, the total insolation is about 1000 watts per square meter. A regular household demand is around 220 watts. The peak sunlight or solar radiation hours is determined by measuring the insolation. 9

The graph on the right shows how the energy collected from a solar panel varies against the area of the panel. The household demand for an average-sized house is around 2,200 kWh per year, and is shown in blue. The green line is a typical evacuated tube solar panel; the orange is a flat plate panel.9

EFFICIENCY VS MATERIAL The other graph shows the efficiency of solar panels as the panel temperature increases. Due to the inefficient geometry of packing glass tubes together, evacuated tube systems start with a lower efficiency than that of flat plate systems However, as the panel temperature increases, the vacuum insulation is verified and the efficiency decreases slighter than of flat plate panels. 13

EXAMPLEA Colorado home had a total of 8002 kWH of energy usage for a year.

8002kWH/365 days = 21.92 kWH/Day21.92 kWH/Day 5.5 = 3.985 kW = 4000W PV System4000W .90 inverter efficiency = 4444W system = 4500W system4500W X $9.50/W installed price = $42,750Federal Incentive (30%) = $12,825Utility Company incentive ($3.50/W) = $15,750Net Cost ($42,750 - $12,825 - $15,750) = $14,175** 9

SAVINGSSolar PV average installation cost is between 4000 and 6500. You will save more than 1200 kg in carbon emissions and you will get between 500 and 1100 from FIT on a 3kW system.14Solar thermal heating installation cost is between 3000 and 5000. You will save 250kg in carbon converting from gas and up to 500kg converting from an electric boiler and you will get a 30 grant to install the system and save around 80 on your energy bill. 1413http://www.ext.colostate.edu/pubs/consumer/10624.htm14http://cleantechnica.com/2014/02/01/real-cost-solar/ Figure: Diagram of a photovoltaic cell[footnoteRef:12] [12: wattpatrol.com]

Figure: Annual Useful solar energy, area compared to the household annual demand [footnoteRef:13] [13: http://www.viridiansolar.co.uk/Solar_Energy_Guide_3_3.htm]

Figure: Varying Efficiency of Solar Panel with Temperature.[footnoteRef:14] [14: http://www.viridiansolar.co.uk/Solar_Energy_Guide_3_3.htm]

http://cleantechnica.com/2014/02/01/real-cost-solar/

REFERENCES www.ext.colostate.edu/pubs/consumer/10624.html wattpatrol.com www.viridiansolar.co.uk/Solar_Energy_Guide_3_3.htm www.new-learn.info/packages/clear/thermal/buildings/configuration/building_orientation.html primedesignpea.com/pdf/2005,_Climate_and_Comfort.pdf almashriq.hiof.no/lebanon/600/610/614/solar-water/idrc/10-19.html www.atmo.arizona.edu/students/courselinks/fall07/nats101s31/lecture_notes/sunpaths.html http://cleantechnica.com/2014/02/01/real-cost-solar/

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