Category Archives: BACKGROUND

Ventilation elements

The most common characteristic elements of natural ventilation have architectural implications stretching from none to substantial. An embedded duct, most often used in low and medium rise buildings, has in itself no architectural implications, whereas wind scoops, wind towers and chimneys can have significant consequences for the silhouette of the building. Chimneys, most commonly utilised as ventilation extracts in low — and medium-rise buildings, seem to be most widespread in the UK. Double facades are most often used to facilitate natural ventilation in high-rise buildings by making it possible to open windows and use them as air path without severe draughts. The majority of naturally ventilated high-rise buildings are located in Germany, and a great deal of them is double fagade designs like GSW Headquarters, debisHaus, Commerzbank Headquarters, Deutsche post Headquarters, MDR Zentrale, ARAG Headquarters, Deutsche Messe AG, and many others.

Interior spaces

The interiors of buildings utilising natural ventilation are designed to promote a natural airflow with minimal pressure drops. This usually results in open plan layouts or layouts where rooms and functions are openly connected with each other. As the various rooms double as an air path, they are "links” in what could be referred to as the "air path chain”. Varying proportions and sizes of rooms depending on where in the air path chain the room is located is thus characteristic for the interiors of buildings utilising natural ventilation. An atrium or a tall lobby, as an example, form excellent stacks where exhaust air can rise and escape through the roof. Such spaces constitute, as an analogy, a combined "engine” and "plant room” as well as an exhaust air path. Such a plant room (an atrium or a tall lobby) is commonly the most exclusive space in the building, serving representation functions. The contrast to the plant room of a mechanical ventilation system housing fans and other air handling components, typically located in the basement or on the roof, is striking. The floor — to-ceiling height is typically generous to accommodate a buffer zone over the breathing zone for stale and warm air. The rather narrow plans seen in many naturally ventilated buildings facilitate generously daylit spaces and good views to the exterior. Exposure of materials such as concrete, stone and brick to provide thermal mass also characterises the interior surfaces of many buildings utilising natural ventilation.

TRADITIONAL VS CONTEMPORARY VS SOLAR

The different aspects of both traditional and contemporary houses are summarised and given in table 15. From the thermal performance point of view, traditional houses are much better than inappropriately designed contemporary houses. This means that thermal performance is not the only criterion by which the use or abandonment of traditional and contemporary houses may be evaluated.

One of the main reasons why contemporary houses are preferred to the traditional is that they provide all the necessary hygiene services, lighting and ventilation. Most traditional houses lack sufficient lighting and ventilation and suffer from shortages in services.

In order to place a contemporary house into perspective, one must exhibit the comparison between the energy performances of a contemporary house, one that was built post 1970, as it relates to its counterpart, a house built with older house techniques, in the traditional way. The most important difference in the construction specifications of these house, as they are portrayed here is in the construction of the traditional house’s wall (adobe versus concrete and bricks) and in the roof (earth versus concrete).

ASPECT

TRADITIONAL

HOUSES

CONTEMPORARY

HOUSES

SOLAR HOUSES

Architectural

Design

-Inward looking with courtyard — Square or rectangular plan — One or two floors — Covered terraces — A body of water and fountain

-Clerestory windows — Flat, domed and vaulted roofs

-Outward looking — Free plan form — Multi-storey blocks — Small balconies — Vast glazed windows — Flat or pitched roofs

-Free plan form — Sufficient glazed windows

-Flat or pitched roofs — Any design

Constructional materials and methods

-Local materials found on the site of the house or brought from a nearby area — Simple constructions — Load-bearing walls

-Materials are mostly imported or locally made with poor qualities

-Frame structures — Simple constructions — No insulation — Non-load bearing walls

-Materials are mostly imported or locally made with good qualities

-Frame structures — Any constructions — insulation — Non-load or load bearing walls

Occupancy

patterns

-Changed.

-The ground floor is used in summer days and the first floor in summer nights and in winter

-Unchanged because of the design restrictions.

-Unchanged or unchanged because of no design restrictions.

Planning

-Compact planning with courtyard — Shortages in services

-Incompact planning. No courtyard — Zoning problems

-compact or incompact planning.

Thermal

performance

-Satisfactory during both summer and winter and at all times.

-Unsatisfactory during the times of overheating and under heating.

-Satisfactory during both summer and winter and at all times.

Non-thermal

comfort

problems

-Necessity of annual maintenance — Shortages in services

-Shortages in natural lighting and ventilation.

-Weathering problems — No adequate house regulations — High influence of the house contractors — Acoustic problems

-no weathering problems

-low influence of the house contractors — no Acoustic problems

Demand

-Decreasing because of being not suitable for contemporary urban life

-Increasing because of social and economic changes and contemporary life

-Increasing because of social and economic changes and contemporary life

Table 1 Comparison analysis: Traditional versus Contemporary

The traditional house follows the characteristics discussed previously. It transpires from the results produced, that the energy performance of the organically insulated traditional house is clearly superior that of the contemporary house with no energy-efficient

considerations. ENERGY-10 is the software used for the specific project and is designed to develop guidelines for low-energy houses.

Annual Ensrcy Use KWYm2

■ Contemporary house ^Traditional house

□ Experimental Solar House

Figure 2. Comparative Barographs. Energy Total annual energy use, plus breakout by heating, cooling, fan, and "other" uses (everything else)

Figure 3. Monthly Average Daily Energy Use Graphs

As was expected, upon comparing quantitatively the Experimental Solar House with the contemporary house, the solar house proves to be far superior in its energy savings performance. For instance, the contemporary house requires an astounding 4.95 Cyprus pounds per square meter for cooling purposes, whereas the solar house requires a mere 1.33. The overall energy requirements for the contemporary house, according the Energy 10 calculations, reach 368 kWh/m2 as compared to 121 kWh/m2 of the Experimental Solar House (figure 2 and 3).

CONCLUSION

The following techniques that were used in historical and traditional houses are used for the design of the Experimental Solar House:

• Clear topographical clarifications

• The positions in orientation to the sun path either to avoid direct sunlight entering the house of the opposite.

• The exploitation of breezes for ventilation and cross ventilation in the room

• The awareness and exploitation of the nature of flora and its use for practical functions (e. g. medicinal plants, fruit-bearing trees)

• A good insulation of walls (30-40cm width) and roofs,

• The small openings on the external walls for maximum insulation (north, east, west).

Elements, which are now fundamentally used in passive architecture, can be found in constructions created since 9000B. C. These examples, illustrate strong characteristics of historical architecture, which serve as fine examples of energy-saving architecture today and are used on the Experimental Solar House. Early examples include:

• The Solarium was predominant whether acting as an arched corridor, as a central axis or even when it evolved into a self-contained space.

• Courtyards, planted mostly with deciduous vegetation like grapevines, providing shade in the summer and admitting the sun in the winter

• Almost all openings placed on the south wall providing natural light and heat.

• Arseres allowed lighter hot air to go out of the house and be replaced by cooler air from outside in the summer

• Thymes (small dense bushes) blocked the arseres in the winter and provided thermal insulation.

• Roofs and floors were constructed in a typical insulating manner

• Courtyards were built to facing southwards, acting as a sunspace, receiving desired solar radiation in winter.

• The solarium admits the rays from the winter sun to penetrate and so solar radiation could be utilised in winter.

• In multiple thermal modes and varied design, the courtyard and the solarium moderate high summer temperatures — their careful construction combined with the surrounding landscaping lower the temperatures around the house.

The best-known applications of passive solar systems used in traditional houses were researched taking into consideration the advantages and disadvantages for Cyprus. It is concluded that the passive systems that are most suited for Cyprus and used on the Experimental Solar House, are:

• Direct Gain: the simplest solar heating system and can be easiest to build. Areas of glazing not only admit solar radiation for heating but also high levels of daylighting and good visual conditions for the outside. Glazing is well researched and cheap and a material readily available. With adequate insulation of the house, it is possible to rely totally on direct gain as a passive solar system used in the case of Cyprus.

• Thermal Insulation: position of insulation externally on walls and roof. Thickness 70mm expanded polystyrene. Overall U-value of walls and roof 0.6 W/m2K.

• Thermal Storage (Interior Mass): The simplest heat storage approach is to construct the house of massive structural materials (reinforced concrete or brick blocks) insulated on the exterior, to couple the mass of the indoor space

• Glazing: For direct gain systems, south facing window area greater than about 10­12% of floor area require thermal mass, well distributed over floors, walls and ceilings to reduce temperature swings. 5% north wall openings are sufficient for cross ventilation during summer nights6. Types to be used: Low emmisivity glazing, argon-filled, double-glazed. Shading can be easily controlled for the non-heating season.

• Solar Control: By use of orientation (one of the long walls is facing south so that the available solar radiation is exploited in the winter), external shading devices, vegetation.

• Shape of house: rectangular but compact design (aspect ratio 1:1.33) with the longer axis pointing East and West7.

• Natural Ventilation: By use of cross ventilation, stack effect, night ventilation and ceiling fans.

Upon construction of the Experimental Solar House, careful monitoring was pursued, in order to measure its performance in use. Through monitoring the house from the 27/11/1999 until 18/12/2001, using computer data loggers, the internal temperature and relative humidity throughout the year remained steady (within the thermal comfort limits), despite the instability of external temperatures and humidity percentages. The best
thermal comfort is achieved in the months of April, May, October and November. These months needed no extra heating or cooling. The results showed that to achieve thermal comfort conditions, ventilation is required in the summer months (June, July, August and September). In this case, natural ventilation actually occurs, or if there are no breezes, then ceiling fans are applied. In the months of December, January, February and March passive solar gains are used to achieve thermal comfort. It must be noted that steps should be taken to avoid over heating in the summer. The same is to be said for the passive cooling needs in the summer. The results show that all heating requirements are covered through solar energy, while natural ventilation or ceiling fans cover all the cooling needs.

Comparative annual energy use was performed using computer simulation software Energy 10 resulting that the most energy efficient is the solar house (121 kWh/m[20] [21] [22] [23] [24] [25] [26]) following the traditional (243 kWh/mf*) and final the contemporary (368 kWh/mP).

Because of Lefkosia’s climate, passive solar architecture works to its full capacity. This means that, a passive solar house has 100% energy saving potential. This theory has not remained at its conceptual stage as the Experimental Solar House has demonstrated it in practice. The construction of the solar house has a purpose that is multifaceted. It is an environmental success as well as an architectural one. The house itself will be able to provide excellent indoor air quality and natural lighting.

Bodrum Ikizada Turkcell Base Station

Wide spread usage of GSM and On the coast of Aegean Sea Unfair foreign interferences forced Turkish firms to create innovative solutions. A no mans’ island was chosen to build a reflector unit. Design is based on a stone cube building shaded by a big panel consisted of 12 PV units to natural cooling.

On summers PV’s in winters wind turbine supplied required energy by the GSM Reflector unit. This combination and harmony of the building to nature consisted a beautiful combination.

The importance of renewable energies is considered by using solar and wind power. The social cost concept is also important in this building, which is usually ignored in energy investments. The special position of renewable energy sources for Turkey is focused on.

Adobe House in Hasandede — Hocamkoy Project

The aim ofthe project is to support and manage the implementation ofthe ‘Ecological — Village model’ in Turkey. This implementation will be a demonstration action focused on the first Turkish application of its kind, near Hasandede village, 90 km from the capital city Ankara. As a reproducible life model it will help building an eco-centric future. Through this ‘Eco-Village model’, a new sustainable life with architectural, agricultural, social, cultural and energy aspects will be designed. The aim is to bring the established village of Hasandede and the projected eco-village of Hocamkoy to form a true model of ecological sustainability in rural Anatolia. Based on the outcomes, new applications will be initiated around the country.

The housing problems of Hocamkoy project will be considered based on ecological aspects. Principles used in the design of area and houses and other common buildings can be summarized as follows;

• Use of architectural characteristics of the vernacular architecture in the region,

• Use ofthe natural building materials

• Importance of the renewable energy sources; use of active and passive solar energy,

• Wind energy and biomass,

• Harvesting waterfrom nature and re-using,

• Composting and recycling domestic wastes,

• Minimization of travel and transport distances.

The most important characteristics of the vernacular architecture of the region are use of adobe as building material. This tradition has decreased even lost at recent years. Adobe is suitable material in respect to its high insulation value and organic structure. Adobe walls are thermal masses which collect solar energy in day time and transfer it indoors space at nighttime.

Energy need of the buildings can be provided by passive and active utilization of solar energy. Buildings will be oriented to the south or south — east which are optimum orientations for space heating in this region. The topography and inclinations of the land are suitable in order to gain more radiation to the buildings. The ratio of the volume to surface will be designed for maximum energy gains and minimum energy losses. Spatial organization and architectural form are firmly interconnected with such factors as solar control, ventilation, insulation, location of (thermal) walls, surface properties, and color. Principles for creating sustainable buildings have been established for some time. Solar collectors will supply domestic hot water and space heating. Solar cells can provide electricity need of the buildings. Wind speed of 5-7 m/s can be used to supply up to 1 kW of energy with a wind turbine having a diameter of 1.5-2.5 m. A Savonius rotor type windmill can be installed in the vicinity of the building, which may be attracting due to its easy construction and noise-free operation.

The climate of the Central Anatolian region is excellent to built a self-sufficient house. A very small amount of space heating requirements during winter months can easily be supplied by south and/or east facing direct gain windows. The small overheating problem, which might be faced during summer months, can be solved by adjustable overhang shading devices and by appropriate orientation of the building for supplying air vents with the help of the wind. A wise insulation and maybe the use of thermal mass walls for some of the rooms might be effective in solving insignificant requirements of cool nights and hot afternoons.

VIP envelope

Vakuum-Insulation-Panel (VIP)

Construction detail

A major share of the total reduction of 90 % in the heating demand is due to the new envelope, where its extreme slenderness and efficiency allowed us to master all technical and optical construction and connection problems. Despite this, by avoiding other changes in the construction we succeeded in keeping the costs close to those of a standard solution. In addition, a ventilation system with a heat-recovery unit was installed.

Architectural possibilities of natural ventilation

The utilisation of natural airflow for ventilation provides architectural possibilities. This was expressed by Juan Lucas Young at Sauerbruch Hutton Architects, the project architect for the GSW Headquarters in Berlin:

“In a way one thing led to the other. At some point the ventilation was pulling the idea of the high-rise, but the high-rise came also and helped create the ventilation concept. They where somehow two things that came together”.

Ventilation of buildings can very roughly be simplified as 1) getting fresh air into the building from the outside, 2) directing the air through the interiors to provide them with fresh air and to pick up heat and pollutants on its way, and finally 3) getting the exhaust air out of the building. The three points are useful when attempting to sort out the architectural possibilities associated with natural ventilation.

The first and the third point; getting air into and out of the building, are manifested in ventilation openings in the building envelope (fagade and roof). These can be accentuated in various ways, and they can be associated with various characteristic elements like e. g. a wind scoop and a double facade. The design and shaping of ventilation openings can
represent an architectural possibility, but they can also be a challenge or a limitation for some designs. Commonly, the ventilation openings are very pronounced in the architectural expression of the building due to their location and size, especially those in the fagade and in some cases also those on the roof. They are by implication considered as an important architectural element. The building can further be shaped or designed in order to increase over and under pressure at designated locations on the building envelope where the ventilation openings are located. The administration building for the Deutsche Messe AG in Hanover, Germany is an example of this where a conscious build up of volumes increases the driving pressure created by wind at the areas in the building envelope where the ventilation openings are placed. The curved facades of both the Deutsche Post Headquarters in Bonn, Germany and the MDR-Zentrale in Leipzig, Germany are examples of the same where the building by virtue of its shape influences the driving pressure derived from wind. It is, however, most common that the characteristic ventilation elements, rather than the whole building, are designed to increase the driving pressure. The wing of the GSW Headquarters, the wind cowls of the B&O Headquarters and the wind towers of IONICA Headquarters in Cambridge, UK are examples of that.

The second point, directing the airflow through the interiors from the inlet opening(s) to the outlet opening(s), represents a great design challenge as the desire for minimal pressure drop for optimal utilisation of the natural driving pressure (from the ventilation point of view) can conflict with the functional needs and requirements of the users of the building. This especially applies for natural ventilation concepts based on cross — and stack ventilation principles where the air paths are much longer than those in single-sided ventilation principles. This challenge involves at the same time substantial architectural possibilities for the organisation and the shaping of the interior spaces in particular, and the overall shaping of the building in general. The possibilities for the interior spaces derive from the fact that the various rooms form links in the "chain of the airflow path”, stretching from inlet to outlet. Depending on a room’s location in the airflow path, different size, proportion, floor-to-ceiling height and so forth is desired from a ventilation point of view. The architectural possibilities that can be derived from this comprise issues related to spatial experience and quality in the interior spaces (volumes, proportions, floor-to-ceiling height) as well as the spatial connections and rhythm of spaces with differing expressions and qualities along the airflow path.

The ventilation principle and the organization of the interior spaces produce new reasons as well as arguments for buildings to assume certain forms and proportions (e. g. GSW Headquarters, B&O Headquarters, Commerzbank Headquarters, Deutsche Post Headquarters and Jean Marie Cultural Centre). The shape of most naturally ventilated buildings have in common that they can utilise daylight in practically all interior spaces, and accommodate view to and contact to the exterior from virtually every spot inside the building. The headquarters of GSW and B&O are prime examples of that. The avoidance of large ventilation plants with belonging components and vertical and horizontal ductworks may in itself result in architectural possibilities and a greater freedom in the design[19].

Experimental Investigation on the Enhanced Thermal and Visual Comfort with a Prismatic Solar Hybrid Collector

Ki-Se Kim, Eun-Chul Kang, and Euy-Joon Lee, Korea Institute of Energy Research (KIER), 71-2 Jang-Dong Yusong-Gu, Daejeon 305-343, South Korea

M. Masaood Hashmi and I. A.Qazi, Pakistan Council of Renewable Energy Technologies (PCRET), Plot No. 25, Sector H-9, Islamabad, Pakistan

Energy saving objectives and improvements of visual comfort in buildings have led to a growing need for a better daylighting system. Visual comfort includes sufficient illumination of the room in general, and the working area in particular, without colour distortion and with the absence of contrast and glare etc. Today, however, with the growing demand for improved illumination quality and with people becoming more aware of the fact that natural resources are finite and that the balance of the global climate is threatened, daylighting principles of traditional architecture are being revitalized.

It is obvious that if daylight is used to offset lighting energy requirements over a larger floor area, additional energy savings can be obtained (Beltran L. O. et al.). As a result, in the past decade a variety of systems have been developed to improve the usage of daylight in office buildings. Scattering systems like windows filled with granular aerogels (Dengler J. and Wittwer V., 1994), light diffusing films (Beck A. et al.) or specular reflecting lamellae and light guiding systems integrated between double pane windows (Koster H., 1989), are some examples. Prismatic layers excluding direct sunlight, via total internal reflection, have also become available. In the following the newly developed daylighting system with prismatic solar hybrid collector (PSHC) panel is described.

The main objective of using the PSHC system is 1) to control the transmitted sunlight by reflecting, refracting, or diffracting its rays onto the ceiling, 2) to obtain the maximum penetration of sunlight for a wide range of solar altitudes, 3) to improve and increase the uniformity of glare-free daylight distribution at all distances in the building under variable sun and sky conditions and 4) to produce better thermal conditions inside the building by transferring the incident solar radiations through the individual glass sheets and prisms (by convection and longwave IR-radiation).

The experimental data is used to assess the performance of the test room equipped with a prismatic glazing panel integrated to the top window of south — facing wall of the room and to evaluate the performance of this PSHC system in terms of thermal and visual comfort. Tests of this study are carried out for twin rooms of same dimensions, one with PSHC window and the other with normal window. The former is called the target room while the later is labeled as the reference room. The thermal and day lighting performance results are presented and discussed, along with recommendations for further research and development.