(Purpose)

The current experiment is about how we can have vernacular ventilation for energy saving strategies and make a city sustainable. The main goal by this experiment is to focus on environmental pollutions and have it under control through energy saving methods. For that a city is considered where all solutions suggested in this experiment will be tested and decided. As any sustainable practice is unique in its terms and conditions, the project is required to be tested in a real city to exactly know about its feasibility. The case study that is used in here is Hashtgerd New Town located in Iran. The method proposed could be utilized in residential buildings up to 3 floors. To better know how the suggested system works a model house is simulated to clearly show what happens in interiors after such installation is used. The final goal by this project is to renovate residential areas in a sustainable way. By making proper use of natural ventilation an awesome amount of energy is saved.

By suggested system usage provided the temperature will be lowered to 22C°in interior spaces and will also make outstanding rate of energy save. It all indicates that for having a sustainable strategy in our cities, starting from energy saving methods brings about best results in developing countries. The current system suggested in this experiment extremely depends on water and wind and lack of water in such areas is a national endurance. The project is necessary to be integrated for the absence of sustainability in new architecture design of Iranian cities. While in ancient times Wind-Catchers [Funnel or Badgir in Persian] were vastly used all over in Iran and could also make their way into nearby countries, there are unfortunately no good solutions for modern time in Iran. To improve life environment in modern cities the current system is suggested. It will be displayed that it could make the city sustainable and economically self-sufficient.

(Traditional funnels malfunction)

As a vernacular ventilating system the funnel performance fluently cools down the building air to good extent without use of electrical energy. It's important to know that traditional Wind-Catcher performance has some defects that may cause malfunction. As the suggested system by this experiment strongly depends on use of funnels, the most significant disadvantages are listed as the following;

In traditional funnels the temperature of the air entered to the building through the drafty is almost equal to ambient temperature outside.

The only effective factor to lower the temperature in funnels is low night temperature that flashes to the exterior walls toward the sky.

Because of limited building materials in funnel structure, the storage of energy has significant limitations and due to the transfer of high temperatures air, this reserve energy is consumed shortly.

In wind speed is about zero Wind-Catchers cannot supply the air amount needed for comfort of people.

(The suggested system)

With construction of Double-skin walls and use of solar tower the automatic blow of the air will consequently happen in the building. Inside the funnel for a negative buoyancy, (cold and heavy weather) air moves down and in double-skin wall of solar tower because of warm air, positive buoyancy will be made to move the air up. By placing suitable humidifier faculty in the port of air entry into the funnel a pleasant atmosphere is created inside by proper temperature and humidity. Construction materials to be used are adobe bricks, clay, plaster and wood. Regional wood has high epithet of good resistance. The sun exposure makes the air in the solar tower warm and eventually suction is created to outside space. Such system can be even on process in absence of wind in the area. Also in the funnel the showering procedure makes the air a little heavy and as a result it moves down. By this we can force the air move in desirable direction without use of any electrical appliance.

Now the question is; how water can move that high for moisturizing the tower duct for entering wind? The method used in here would be through use of Commuting Vessels Law. Hashtgerd NT has good topographic potentials for optimum use of land altitude. For every block of buildings a water pond is suggested for flooding wind-towers on lower altitude. By increase of water injection the temperature decreases until a glut amount is achieved so in this case more water will not be wasted through evaporation procedure. This effect alone can help a huge save of water in the tower. On the other hand inside solar chimney because of sun exposure to the interior wall and passage of it through the tower hot air moves up and works like a fan.

(The model house simulation with funnel)

For better simulation it is needed to consider some portable elements in the model house for making more accurate simulation and understanding of the air circulating behavior in the space. In the room some very popular household items are also determined that in thermal simulation are also considered. The following figure shows the model house presented by FLUENT software. Solar Tower and Wind-Catcher with common furniture are used.

Right after the system starts to work, temperature and wind in the model house show significant alteration. The best time to clearly verify its condition in the area is 20min after when the system starts to operate. The following figures display the effect of ventilation and temperature diversities on furniture and people in the space.

The system suggested in here is tested for Hashtgerd city to figure out if the place can become sustainable by this model. By EMS method it was shown that the city can become economically self-sufficient and it's now time to figure it out if the place is also sustainable or not? It is proposed to be used in Hashtgerd NT new buildings. It also declares the temperature can be lowered up to 22℃in the building while the outside temperature is around 40℃. The system suggested here can be successfully used in residential buildings up to 3 floors. The level of comfort and amount of air transferred stands out at an acceptable level to show all vital standard acquired in any sustainable development. By using FLUENT software we elicit the fact that the system lowers the temperature below ambient and can make the city self-sufficient. It will be time to verify if by using the system the city can also become sustainable?

(TOPSIS modeling of the case study)

We have u methodologies as our alternatives [A1, A2, . . . , Au] for making vernacular ventilation. On the other hand we need some methodologies that are shown as Sij. The Ideal point or satisfactory ratio considered lies within the domain that will be latterly calculated. We need it for preparing the matrix that is followed however before that we need to determine the criteria elements alongside with possible alternatives. The main concept in this project has is to figure out best methodology to make sustainable urbanity by vernacular architecture. The alternatives used are as follows;

Construction price

Lifetime and validity period

Organic and nonorganic materials

Emissions rate

Space occupation

Aesthetical views and architectural design method

Comfort coefficient obtained

Temperature difference observed

Ecological considerations

Maintenance and rehabilitation costs and overhead expenditure

Now it is needed to normalize the numbers as the following. The alternatives in TOPSIS method are normalized by the following formula;

j= i∈[1,2,..,u] , j∈[1,2,..,v]

Beyond it we should also notify the Ideal Point and Anti-ideal Point for further calculations. We can even consider them as Positive Ideal Solution and Negative Ideal Solution that could be defined as the following;

A+=, i∈[1,2,..,u] , J

A-=, i∈[1,2,..,u] , J

For interior options the method to calculate is as is followed;

Di+=, Di-=i∈[1,2,..,u ]

The operations up to here will produce the scrambled index that needs to be sorted. Moreover a relative closeness coefficient or an initial Di is needed to determine the correct order of all attained points. To precisely determine the relative closeness coefficient D+i and D-i are also needed for each point that was previously shown as Dij. They are all calculated as the following;

Di+=, Di-=i∈[1,2,..,u]

To verify which amount stands out to be the answer or not the following consideration should be taken into granted. If we show the final result as Ri it will be extracted from the table as below;

Ri =; i∈[1,2,..,u ] , Di+ ≠ 0 ⇒ (Ri → 0 if Di-= 0), Diー ≠ 0 ⇒ (Ri → 1 if Di+=0)

However in most cases the result or Ri is an amount between [0,1]. Now we have all is needed to make the allocation table. By implementing the so-mentioned method on real data we would get the following results that clearly partially show the sustainable situation in Hashtgerd NT. The final results based on the mathematical method explained for Hashtgerd can be accurately obtained. The results are displayed in the following table. From this table we can finally understand whether Hashtgerd NT is a sustainable city after using vernacular ventilation or not? The details of the table are explained in the following page.

Considering the table above we find out C4 represents a number a lot different and is considered as unwanted criterion. By omitting it we can obtain D+ as is deducted from the amount above.

Where i=1.877 ∈S6, Di-= .65 Ri=.25, i∈C6 is FANTASTIC quantity & Acceptable

The above numbers based on TOPSIS method of analyzing numbers will clearly indicate that Hashtgerd city can be considered as a sustainable urbanity from vernacular architecture methods. Ri that is illustrated above indicates the closest criteria to A+ as our Ideal alternative. So we should consider the weights which are assigned have to address methodologies for sustainable planning, for development of new urban fabric or for documentations of infrastructure manuals. Possibilities of integrated planning and infrastructure development to increase energy-efficiency depend on many factors that can be added to the alternatives considered in here. However natural ventilation alone methodologies could bring about favorable urban comfort. Iran's ethnic architecture has good solutions that if they are efficiently used can make all areas a kind of sustainable unity.

1 Cupic, M., and Suknovic, M., Multicriteria decision making: formal access, Faculty of Organization Science, Belgrade, 2003.

2 Pavlicic, D., "Normalisation Affectes the Results of MADM Methods", Yugoslav Journal of Operational Research,11 (2) (2001) pp.251-265.

Isometric view of the model house

Residuals simulation- 5 min after use

Residuals simulation- 10 min after use

Residuals simulation- 15 min after use

Residuals simulation- 20 min after use

Residuals simulation- 25 min after use

Residuals simulation-25 min after use

Data Analysis Modeling Table

世界中の大都市が急激な都市化の波に直面している。市街域を拡大することで対応しているが、限界を超えると、その周辺にニュータウンが造成される。急造のニュータウンは近代的な技術を駆使して自然を人工的なものに改変するが、その結果として、極めて無機的な空間が出現している。こうしてできたニュータウンは、災害に弱く、また、そこに住む人々は良質なコミュニティを形成することができないでいる。エネルギー消費の面からも浪費が多く、自立性、あるいは持続可能性の面からも多くの問題を抱えている。

本論文は、イランのニュータウンを対象に、こうした問題点に対するひとつの解決策を提示するもので、イランで伝統的に使用されてきたさまざまな技法を組み合わせることにより、環境負荷が少なく、かつ、循環型の社会を再構築できることを示している。特に、着目しているのがペルシャ語でBadgirと呼ばれる通風筒で、これに工夫を加えることにより、建物内の空気環境を大幅に改善できることを示している。

通風筒はイランだけでなく、北アフリカから中東にかけての砂漠気候の地域に広く分布している採風装置で、その歴史は数千年に及ぶ。通常、通風筒は、日中は排気と冷気の取り込みを行い、夜間は、排気のみを行う。この通風筒による大気の循環をより効率的に行うためにソーラー・チムニーを併設する場合がある。ソーラー・チムニーは、日中、太陽光を浴びると内部に上昇気流を生じ、それが建物内部の空気の循環を促す。こうした装置はこの地域では古くから用いられていて、今でも有効に機能している。大気は循環の過程において中庭の植栽や噴水・池等で冷却されるが、その冷却効果は小さい。これを改善するために通風筒の上部から霧を降らせる方法がある。霧は通風筒の内部を落下する間に蒸発するが、その際に多量の気化熱を奪う。このシステムを用いると、効率的に空気を冷やすことができる。砂漠地帯でよく利用されている冷風扇と同じ原理である。この効果をさらに高める工夫として、地下水道(Qanat)の冷気を室内に取り込むことも考えている。これらはいずれも土着の技術で実現可能なもので、安価でクリーンなエネルギーを消費する。

論文全体は10章からなる。

第1章では、研究目的について述べ、イランの伝統的な採風装置を現代のニュータウンに取り込む意義として、都市の自立性を高め、持続可能性や省エネに寄与するとしている。

第2章は、研究対象となるHashgerdニュータウンの説明である。この町は、現在も建設中で、さまざまな計画案が作成されているが、その概要を図版と写真等で示している。

第3章は、対象地域の気候条件(温湿度、風向、風力、日照時間等)に関するデータのまとめである。

第4章は、水に着目しながら、伝統的な貯水槽や気化熱の利用方法、地下水道等を説明している。また、ニュータウンで常に問題となる、上、中、下水道のシステムについて検討している。

第5章は、水の再利用の仕方に対する提案で、ニュータウン内の望ましい給排水システムについて解説している。

第6章は、大気の正圧、負圧により風の流れがどのように形成されるかについて概説し、次いで、風を利用した換気システムのいくつかを紹介している。また、Hashgerdの月別の風配図を載せている。

第7章は、伝統的な通風筒に関する詳しい説明で、その仕組みと風の流れ方を示し、次いで、中東地域のさまざまな通風筒を取り上げて、それぞれの特性をまとめている。また、イラン各地の通風筒について、風の取り入れ口の形や筒の断面形に基づく分類を行なっている。

第8章は、ニュータウンの空冷システムについての提案で、通風筒を導入したモデル住宅を想定して、気流や温度等がどのように分布するかをシミュレーションにより検討している。分析には気流解析のソフトを用い、システムの有効性を確かめている。

第9章は、経済効率の分析で、エネルギー・マネージメント・システムを活用した場合に、経費をどのように削減できるかを試算している。また、これまでに提案してきた手法が持続可能性の観点から有効であるかを確かめるために、TOPSIS法を用いてその効果を評価し、有効との判断を得ている。

第10章では、章毎のまとめに続いて本論の結論を述べているが、通風筒やソーラー・タワーに加えて、周辺環境の植生や水の循環システムなどを有機的に整備することにより、風土に適応した合理的なシステムを形成できるとしている。最後に、将来的な研究課題について言及している。

以上要するに、本論文は、現在開発中のニュータウンに対して、住居の風環境をどのようにデザインするのが合理的であるかということを、伝統的な風や熱、水に関する叡智を再活用する形で提言したものである。かつて、林立する通風筒はイランの街のシンボルであったが、エアコンの普及と共に次第に廃れている。使用するエネルギーや経費を考慮しないのであれば問題ないが、持続可能な循環型の社会が望まれる今、本研究の成果は、この地域の住宅の風環境に関して一つの解答を示したものである。今後、検討すべき事項も多いが、伝統的なシステムは、その有効性をすでに歴史が保証している。それらを更に改良して現代に活用しようという本論文の提案は極めて現実的で、その有効活用が望まれる。本研究で取り上げた事項は、良好な住環境を設計する上で大いに参考になるもので、都市・建築計画学における意義は極めて大きい。

よって、本論文は博士(工学)の学位請求論文として合格と認められる。