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KilosaBuilding

MercuryHouse

138

NHCBank

SH1G

Square

OldOrphanage

Building

ForodhaniPlayground

Mizingani Street

Hyatt Road

TemboHotel

Indian Ocean

OldFort

ForodhaniPark Hotel

Mizingani Street

Gizenga Street

Beach

ForodhaniGardens

5455

56 53

128A/B/C

SH1H

RoscherBuilding Power

House

Mizingani Street

House ofWonders

Gizenga Street

Ken

yatt

a St

reet

Ken

yatt

a St

reet

Mizingani S

treet

Site Inventory & Analysis

Climatic Analyisis

Zanzibar experiences a regular pattern of the monsoon winds. These arethe same winds that allowed for traders to plan their trade routes southand north along the East African coast through the Indian Ocean.

-Kaskazi (north-easterly) December to mid-MarchThis wind took traders south along the coast, blowing from thenortheast to the southwest for approximately 4 months

-Kusi (southerly) April to mid-SeptemberThis wind allowed traders to head up north along the coast. A mainlysoutherly wind blowing for approximately 6 months.

SUNPATH

Psychometric Chart Analysis. Bioclimatic Chart Analysis.

Climatic DescriptionZanzibar lies in the warm humid climate. Warm humid climate isgenerally found within the region 150 North and South of the Equator.Koenisberger (1975) observes that the most prominent characteristics ofthis type of climate are the hot, sticky conditions and the continualpresence of dampness. The climate has very little seasonal variation andthe air temperatures range between 210C- 320C during the day and 210C-270C in the night. The temperatures barely exceed the normal skintemperatures.The relative humidity levels are high of about 75% throughout the year.Heavy clouds and water vapour in the air act as a filter to solar radiation.However the same clouds prevent reradiation from the earth at night.Precipitation is high throughout the year with annual rainfall varying from2000mm to 5000mm and may exceed 500mm in one month. Windvelocities are generally of low speed. However strong winds can occurduring rain squalls and usually in one or two dominant directions.

Recommendations

Winds

Temperatures in Zanzibar are high during the short dry season of Januaryto February, with maximum mean of 32°C, and low during the coolseason lasting from May to September. The cool season, also known asKipupwe in Swahili may be associated with periods of scattered showerscalled Mchoo in Swahili. The mean annual maximum and minimumtemperatures are 29.3°C and 21.1°C, respectively.

Temperatures

SunpathThe sunpath cuts diagonally through the site. This will inform theapproach that will be taken in design of individual buildings. In as muchthe project is all about conserving and maintaining the buildings as muchas possible, the new redesigned buildings will be adequately designed tominimize the effects of direct solar radiation into the spaces. In theinsatance wher the building oreintation cannot be altered to have theshorter facades on the east and west directions, adequate sunshadingmeasures will be employed i.e lourvered windows. Furthermore for the purposes of having adequate natural lighting in thebuildings, the said buildings will be oriented to have larger windowopenings on the North and South facades at the same time having narrowplans to avoid deep spaces.

Winds

The relative humidity is high, with a monthly average ranging from 87%in April (Masika) to 76% in November (Vuli), and a minimum at 60%during the dry season. Therefore, with humidity values in the range of80%, daily temperatures can sometimes be as high as 40°C particularly inthe night when the land is braced with hot breezes.

Relative Humidity

Previous studies on design for the warm humid climate indicate that forthe purposes of achieving human thermal comfort in buildings it is onlywise to depend on air movement within spaces to provide the all improtantphysiological cooling. This arises from the fact that the humidity levelsare high rendering cooling by sweating almost irrelevant. It therfore wiseto maximize in the use of the sea breeze in providing physiologicalcooling needs in the buildings. This will be achieved in having windowopenings deliberately done to allow for air to get into the spaces .

The sunpath cuts diagonally through the site. This will informthe approach that will be taken in design of individual buildings.In as much the project is all about conserving and maintainingthe buildings as much as possible, the new redesigned buildingswill be adequately designed to minimize the effects of directsolar radiation into the spaces. In the insatance wher the buildingoreintation cannot be altered to have the shorter facades on theeast and west directions, adequate sunshading measures will beemployed i.e lourvered windows.

The bio-climatic chart defines the comfort zone using two mainparameters i.e the Dry Bulb Temperature (DBT) and the RelativeHumidity (RH) of 20-30 degrees celcius and RH of 30-65%Two months of extreme weather have their data plotted i.e Decemberbeing the hottest month and represented by the red line and July being thecoldest month and represented by the blue line.

Deductions from the chart shows that there is need to put measures thatseek to provide cooling in buildings for physiological cooling andconsequently achieving the comfort levels.

The Psychometric chart has a comfort zone defined of about 20-26degrees celsius and R.H of about 20-80%.Plotting of figures of the same two months i.e December being the hottestmonth and represented by the red lines and July being the coldest monthsand represented by the blue line, clearly shows that none falls within thecomfort zone.

Deductions from the chart shows that there is need to put measures thatseek to provide cooling in buildings for physiological cooling andconsequently achieving the comfort levels.

This chart shows how frequent and how strong the wind blows fromdifferent directions through a typical October. The biggest spokes point inthe directions the wind most commonly blows from and the shade of bluesuggests the strength, with the strongest winds shown by dark blue. It isbased on 2232 NWW3 forecasts of wind since since 2006, at 3hr intervals,for the closest NWW3 model node to Zanzibar, located 35 km away (22miles).It is only wise that the redesigned buildings and the existing buildiing totake advantage of this winds to ensure thermal comfort of the eventualusers. It is apparent that in order to achieve thermal comfort for this regionis by ensure that there is air movement for physiological cooling given thehigh humidity levels.

Prevailing Winds

Sea Breeze