Mehdi N. Bahadori

Sharif University of Technology | SHARIF · Department of Mechanical Engineering

Ice-Houses: Energy, Architecture and Sustainability introduces a novel, sustainable, natural/low-energy technology that relies on daily/seasonal ice production and storage methods to reduce electricity use in buildings, particularly at peak times, while simultaneously meeting inhabitants’ thermal comfort needs and decreasing GHG emissions. Both tra...

Passive cooling systems such as wind towers or wind catchers can create thermal comfort for building residents in hot and dry regions. This paper introduces an experimental study of a modular design of wind tower called the modular wind tower with wetted surfaces. Air temperature, relative humidity (RH) and airflow velocity parameters were measured...

Wind towers or wind catchers, as passive cooling systems, can provide natural ventilation in buildings located in hot, arid regions. These natural cooling systems can provide thermal comfort for the building inhabitants throughout the warm months. In this paper, a modular design of a wind tower is introduced. The design, called a modular wind tower...

Aquifers are underground porous formations containing water. Connned aquifers are surrounded by impermeable layers on top and bottom, called cap rocks and bed rocks. A connned aquifer with a very low groundwater ow velocity was considered to meet the annual cooling and heating energy requirements of a residential building complex in Tehran, Iran. T...

Aquifers are underground porous formations containing water. Confined aquifers are formations surrounded by two impermeable layers. These aquifers are suitable for seasonal thermal energy storage. The objective of this research is a parametric study of the pressure distribution in an aquifer to be employed for thermal energy storage for air-conditi...

Passive cooling systems such as wind towers or wind catchers can create thermal comfort for building residents in hot and dry regions. This patent introduces a modular design of wind tower called the modular wind tower with wetted surfaces. Air temperature, relative humidity (RH) and airflow velocity parameters were measured at different times and...

This unique volume provides the only holistic treatment of wind towers, a core aspect of sustainable architecture in hot, arid climates. The authors explain how traditional incarnations of these structures provide significant decreases in energy consumption through their use of renewable wind resources to cool buildings and water storage facilities...

This chapter illustrates pictures of the Baudgeers in Iran and other Middle Eastern countries including Egypt which were built in houses and water reservoirs. Baudgeers in Iran are used in both hot arid regions and humid regions. Egyptian and other Middle Eastern Baudgeers have also been used in different climatic regions (Figs. 9.1, 9.2, 9.3, 9.4,...

As mentioned in Chap. 1, conventional wind towers or Baudgeers suffer from inadequacies, some of which are pointed out here:

There is no precise date or information about the antiquity of Baudgeers. However, acquaintance of ancient Iranians with the characteristics of the airflow and the use of Baudgeers undeniably indicates that the invention and development of these structures is Iranian knowledge [1]. Based on his studies on the emergence and development of Baudgeers,...

To investigate the performance of the new designs of Baudgeers and comparing them with the old models, creation and testing of sample structures was carried out in the province of Koh-Gilueh Buyer Ahmad-Londeh, Asr-e-Enghelab Research Complex, near Shahryar, Tehran and University of Yazd, Yazd province.

Baudgeers of Iran are divided into four general types:

Figure 4.1 indicates the cross section of a conventional wind tower or Baudgeer which has been chosen for study and analysis. The Baudgeer consists of three parts: mouth (head of Baudgeer), column, and blow conveying hatch.

In this chapter an additional numerical–analytical operation of the conventional and modern structures (Baudgeers with wetted column and wetted surfaces) is discussed, operating in identical physical and climatic conditions.

To study and assess the performance of the conventional (or traditional) and new designs of Baudgeers, samples (models) of each type with identical specifications were used. The new models included the ones with wetted columns and with wetted surfaces. The mathematical and empirical performances evaluation of the Baudgeers was carried out between 1...

Aquifers are underground porous formations containing water. Confined aquifers are the formations surrounded by two impermeable layers, called cap rocks and bed rocks. These aquifers are suitable for seasonal thermal energy storage. In the present study, a confined aquifer was considered to meet the cooling and heating energy needs of a residential...

Domed roofs have been used in Iran and many other countries to cover large buildings such as mosques, shrines, churches, schools. They have been also employed in other buildings like bazaars or market places in Iran due to their favorable thermal performance. The aim of this research is to study about domed roofs thermal performance in order to det...

Domed roofs have been used in Iran and many other countries to cover large buildings such as mosques, shrines, churches, schools, etc. However their favorable thermal performance made them to be employed in other buildings such as bazaars, or market places, in Iran. The aim of this study was to determine the air pressure distribution over domed roo...

Solar radiation received and absorbed by four domed roofs was estimated and compared with that of a flat roof. The domed roofs all had the same base areas, and equal to that of the flat roof. One of the roofs considered was the dome of the St. Peter's Church in Rome. Compared with the other roofs considered, this dome had a higher aspect ratio. It...

Domed roofs have been used in Iran and many other countries to cover large buildings such as mosques, shrines, churches, schools, etc. However their favorable thermal performance has allowed them to be employed in other buildings like bazaars, or market places in Iran. In this investigation, wind pressure coefficients were determined experimentally...

Two new designs of wind towers were tested side by side with a conventional wind tower in the city of Yazd, Iran. All the towers were of identical dimensions. The two new designs were one with wetted column, consisting of wetted curtains hung in the tower column, and the other one with wetted surfaces, consisting of wetted evaporative cooling pads...

Micro gas turbines are considered to meet the electrical, domestic hot water, heating and cooling energy needs of a residential building located in Tehran, Ahvaz and Hamedan. The building is 10 stories high and has a total of 8000m2 floor area with the peak demands of electricity of 32.96kW, DHW of 0.926kW, heating load of 1590kW and the cooling lo...

Using domed roofs to reduce building solar load in hot arid area is one of Iranian mechanical engineering masterworks. The first application of these roofs was to cover large buildings such as mosques, shrines, etc. However their thermal performance made them to be employed in other buildings like bazaars. The aim of this study was to determine the...

The Social Cost of nuisance noise from a wind turbine is defined here as the additional cost to reduce the noise level at a receptor to an exceptable, non-nuisance value, i.e. to mitigate this cost. This acceptable sound level is considered to be 35 dB. Our example is a 10-kW (nominal power) wind turbine considered to supply the electrical energy n...

The power output of gas turbines reduces greatly with the increase of inlet air temperature. Aquifer thermal energy storage (ATES) is employed for cooling of the inlet air of a gas turbine. Water from a confined aquifer is cooled in winter, and is injected back into the aquifer. The stored chilled water is withdrawn in summer to cool the gas turbin...

The passive cooling effects of a courtyard of a small building were determined numerically, employing an energy-analysis software developed for that purpose. The passive cooling features considered were the shading effects of courtyard walls and two large trees (of various shapes) planted immediately next to the south wall of the building, the pres...

The airflow rate through a two-story building with a courtyard, with and without trees, was estimated and compared with that of a building without a courtyard. The building and the courtyard were of square shapes, each 10 m to the side. The courtyard walls were 3m high and two separate trees of spherical, cylindrical and conical shapes were conside...

Wind towers are architectural designs employed for natural ventilation and passive cooling of buildings. In this study, it is shown that the performance of these towers can be improved appreciably by incorporating evaporative cooling in them. Two designs, called wetted columns and wetted surfaces, were employed, and their performances were evaluate...

Operation of conventional wind towers, or Baud-Geers, are described. Wind towers maintain natural ventilation through buildings due to wind or buoyancy effects. The tower structure is cooled externally through radiative transfer with the sky, and internally with the cool ambient air, circulated through the building and the tower during the night. D...

Seasonal storage of chilled water in a large underground reservoir was studied by considering a two-dimensional heat flow in water and the soil surrounding the cistern, and by employing a finite-difference technique for the numerical solution of the energy equations. The cistern considered in the analysis was similar to those which have been employ...

Wind pressure coefficients at various openings of a wind tower were determined by testing a scale model of the building in a boundary layer wind tunnel. Wind towers (or Baud-Geers) are structures which have been employed in Iran and neighbouring countries for natural ventilation and passive cooling. Tests were conducted on an isolated tower, the to...

Hourly, daily, monthly and annual heating and cooling requirements of a residential building located in Ottawa, Ontario, Canada were estimated, employing ENERPASS as the energy simulation tool, and performing hour-by-hour energy analysis. The following weather data were employed: 1. (i) Ten years (1967-1976) of weather data. The ten-year average of...

The inside air and the mean radiant temperatures of two buildings, one built of brick having a flat roof and the other built of lightweight adobe and having a domed roof, were estimated through a thermal network analysis. The analysis was repeated for both buildings when their ceilings and inside wall surfaces were kept moist and evaporatively cool...

Recent research in summer air conditioning utilizing natural sources of coolness* are discussed. These systems are classified according to the sources of coolness, the modes of heat transfer and airflow, and the types of material employed for the storage of coolness. The sources of coolness are the ambient water vapor, ambient air, and the upper at...

Recent research in summer air conditioning utilizing natural sources of coolness are discussed. These systems are classified according to the sources of coolness, the modes of heat transfer and airflow, and the types of material employed for the storage of coolness. The systems considered are classified according to the climate - that is, systems e...

A covered ice pond was analysed for the gradual production, storage, and utilization of ice for air conditioning of a building with an annual cooling demand of 1.2 TJ. Winter ambient air, blown into the pond for ice production, provided the major sources of coolness. The ice production rate and the total height of ice which can be produced were det...

Natural ventilation due to wind effects through buildings employing domed roofs was estimated by a flow network analysis. The dome was assumed to have an opening at its crown. When compared with flat roofs, the domed roofs always increase the air flow rate through the building. The increase in natural ventilation becomes significant in buildings wi...

A design is proposed to improve the performance of wind towers (or Baud-Geers) for natural ventilation and passive cooling. Under similar climatological and design conditions, the new design is capable of delivering air to the building at higher flow rates. It can also cool the air evaporatively to lower temperatures. Higher airflow rates and the e...

Weekly storage of coolness in heavy walls (walls with large thermal inertia or large characteristic time constants or low Fourier numbers) was investigated numerically by considering one-dimensional heat conduction through the walls. The study consisted of first analyzing the heat flow through a single wall and considering various boundary conditio...

Natural cooling systems are described and classified according to sources of coolness‡ storage materials, and modes of fluid flow and heat transfer, as well as the duration of storage. Ambient air, water vapor in the air, and clear sky provide the major sources of coolness, for both short-term (a few hours) and long-term (a few months) storage. Mat...

The operating principle of the 'Baud-Geers' wind towers traditionally used in Iran for ventilation and passive cooling of architectural structures is presently adapted to house a vertical axis wind turbine. Unlike annular diffuser-augmented, horizontal axis wind turbines, the 'wind tower' does not have to be trained into the wind and generates less...

Ice production and storage systems can be designed to meet the cooling and dehumidification needs of new and existing buildings and to reduce the peak cooling needs and utility demand changes. The ice production processes are classified as passive, low-energy and high-energy systems. In the passive ice production techniques no prime source of ener...

The seasonal storage of coolness in the ground, in a rock bed, in aquafers, in the form of ice (in both covered and uncovered ice ponds), and in the form of frozen soil were studied. A storage capacity of 10 TJ for the aquafer and 1 TJ for all others were considered. The technical and economic feasibilities of each system were considered for each o...

This chapter discusses the solar energy development in Iran. It describes an air heater that was built in the 1970s as a part of a home air heating system. In many parts of the country that have low temperature and good sunshine solar energy is feasible for heating. However, at present, it is no longer feasible, when comparing the actual costs vers...

The paper describes the principle of operation of wind towers and curved roofs used for natural circulation of air through buildings. The wind towers can provide both sensible and evaporative cooling of the air, while the wind blowing over the curved roofs provides an entrainment and sensible cooling of the ambient air through the building. The nat...

Several methods of solar energy utilization are considered for a residential town of about 4000 people in Iran. The methods involve central generation of all energy needs, with parabolic concentrators used for power production and flat plate collectors for water vapor production and domestic hot water. Consideration is also given to the utilization...

The principles of solar water pumping are briefly described. The mechanical energy needed for pumping water may be produced by thermodynamic, or direct-conversion methods. In thermodynamic conversion a fluid with high internal energy is produced in solar collectors or concentrators. The internal energy of the fluid may be utilized in Rankine-, Bray...

The performance of the natural ice makers or “Yakh-chal” which provided ice for centuries in most of the Iranian cities was studied both experimentally and analytically. It was shown that in clear winter nights when the ambient air was as high as 4 °C and when the wind velocity and the relative humidity ranged between 0–10 Km/hr and 30–60%, respect...

The techniques employed traditionally to climatise buildings and provide cold water and ice for hot summers in iran's arid regions using solar and wind energy are described. These architectural techniques include wind towers to capture and circulate cool air to buildings, air cooling systems employing both evaporative and sensible cooling, domed ro...

Developing countries need to relearn the dwelling styles and construction methods of earlier times and to lay emphasis on the conservation of energy and the use of passive systems. Some of the techniques for solar energy utilization which can employ both indigenous materials and local manpower are discussed, with emphasis placed on passive systems....

The solar energy research activities of several universities in Iran up to June 1975 are briefly described. The activities at Pahlavi University in Shiraz include the development of solar air heaters, water heaters, steam cookers, dehydrators desalinators, sterilizers, and power production and a feasibility study of solar house heating in Iran. The...

Measures are suggested for global planning for more effective solar energy utilization including more efficient energy conversion or energy conservation. It is shown that by effective global planning it is possible to make better use of available energy resources and to improve the quality of the environment, thus using solar energy more effectivel...

A portable solar autoclave was designed and tested for the sterilization of up to 7.5 kg of medical instruments. the unit consisted of two coaxial cylinders, the inner one housing the instruments and the outer one receiving solar energy which was reflected by segmented mirrors covering the inside surface of a truncated cone. The spacing between the...

Thermal energy storage using sensible heating and physical and chemical changes are considered. The sensible heating process includes the storage in building elements, water, and rock beds. Advantages and disadvantages of each are given. Thermal energy storage through physical changes including solid-solid, solid-liquid, and liquid-vapor transition...

A single-glass, flat-plate solar collector for air heating is analyzed for an optimum tilt angle of 45° for Shiraz (29° 36′ N latitude, 52° 32′ E longitude, and elevation of 4500 ft). The absorbed and utilized solar energy, as well as the collector outlet air temperature, the glazing, and the blackened plate temperatures, are determined with respec...

Glass still glazings are treated with sodium silicate or hydrofluoric acid to make them more wettable. Consequently, the angle of inclination can be reduced to 1·5°. Stills of low glazing height are ammenable to diffusion mass transport which is expressed for the natural parameters of air temperature, wind, and solar energy intensity and for vapor...

Non-equilibrium transport properties of partially ionized argon and the nature of relaxation of electrons at a cooled surface were studied with measurements made on a steady flow two-dimensional arc-heated channel. Study consists of extension of boundary-layer theory to the case of flow of an ionized gas over a cooled wall, and evaluation of transp...

Die Arbeit behandelt das Verhalten eines teilweise ionisierten Gases in einem elektrischen Feld sowie die experimentalle Bestimmung von Transporteigenschaften, beruhend auf einer modifizierten Grenzschichttheorie und Messungen in einer zweidimensionalen Kanalstrmung.