Solar energy can be used in addition to the heating system for a family home when the home is well-sealed and thermally insulated. In this situation, a large, well-insulated storage tank and its management systems will be required. This system is not only more expensive to produce, but also requires more space. In the winter, this system will need auxiliary back-up via “traditional” systems (e.g., electric, gas or bio-mass). During the summer, this large production of energy can be difficult to manage unless it is used to heat swimming pools.
Rule of thumb: Auxiliary solar heating is cost effective when 1 m² of solar collector is used to heat a planned area of 5 m² inside the building (and more efficient when a vacuum tube system is used).
Therefore, 30 m² of collectors will be required to heat an area of 150 m² in the home and necessitate two 1000-liter, insulated hot water storage tanks. A bio mass boiler (pellet boiler), gas or electric boilers will be needed when there is no sun. These systems work best when floors, walls and ceilings are to be heated to reduce surfaces that create heat loss.
One – at present, less developed – method of heating with solar energy is the use of an air collector.
Due to its nature, it is good to use together with air heating. The system is very economical, but it
still has some weak points: the need for both a heat-containing medium and noise buffers. However, it is good to use air collectors for heating if the building is equipped with a ventilation system that filters dust and pollen, provides a good solution for acoustic disturbances, and has precise, automated controls. At present, it is most appropriate for use in small public buildings.
Rule of thumb: Solar hot air collection is cost effective when 1 m² of solar collector is used to heat a planned area of 10 m² inside the building and controlled by a mechanical ventilation system. A bio mass boiler (pellet boiler), gas or electric boilers will be needed when there is no sun.
Solar production of electricity is an alternative to production of heat when used for electrical lighting and kitchen and household appliances. Local production of electricity requires solar cells and storage batteries, or electricity not used at the time of generation can be fed into a public supply network.
Currently, the power generated is low voltage direct current, which can only be used for light fittings and refrigeration systems. This is why electricity is stored in batteries and must be converted to an alternating current mechanically. This conversion is done by an inverter. Electricity-generating elements can be placed on the roof or integrated with glass windows. (A south-facing sun room could be glazed with solar cells.)
Rule of thumb: Solar generation of electricity is not viable if used in isolation for residential installations due to the cost of initial installation and maintenance. It is better used as an addition to power supplied by "grid" or public utility providers. These technologies are rapidly evolving and might see an improvement over the next ten years.
Wind energy is a possibility, but not discussed in this publication due to the complex scope of subject.
Bio mass as a renewable energy source is being widely promoted. When a home is well-insulated and passive solar gains are solved, then bio mass solutions can be satisfied. These solutions might be wood or pellet burning boilers for reasons of cost effectiveness or environmental impact. These are similar to conventional gas-fired storage boilers, but require fuel-storage hoppers, special chimney systems and precise automatic control. To produce the same energy output as a gas-fired system using 1 m³ of gas, a bio mass central heating system requires 1.8 kg of pellets or 3.0 kg of firewood.
Hot water can be produced on a traditional brick or cast iron fireplace. This is usually required when cooking or on demand, and it can be time consuming. This option is only truly economical if an activity in the home produces enough combustible matter to make it worthwhile.
Rule of thumb: The heating-season firewood demand for a 150 m² house is about 2000 kg (2.2-2.8 m³) or 3000 kg of pellets (1.7 m³). Older buildings require more.
Traditional brick stoves are a good option for 3-4 room homes.
Housing
4.1. Preface
Low-rise, high-density housing is not a commonly recognized building type in the Hungarian language.
In Hungary, these building types are officially referred to as being "housing grouped in closed rows".
OTÉK defines this group as row houses, chain houses and a collection of atrium buildings. In fact, the range is broader. (Some examples are given in fig. 4.1.) Row housing units may be grouped, even though they occupy distinctly separate building plots. As we shall later see, this is only one type of development that jointly occupies a building plot (e.g., residential complexes and housing estates).
In this case, for lack of a better choice, the same regulations apply as to "free-standing" buildings or groups of buildings. This category of development is rather sloppy in terms of definition when compared to other "use" types, and it may include different variations on the same theme.
Figure 4.1. Low rise, high density housing schematic examples
Low-rise, high-density housing covers a wide spectrum of development which overlaps with multi-level, multi-unit housing. A single building plot may provide the location for a line of row housing, which might be structurally linked as a multi-level, multi-unit property or even by a common underground garage. A development might consist of individual homes with private gardens that are joined by a common space (a covered atrium or "closed street"), which also applies to multi-level, multi-unit homes.
Low-rise, high-density housing usually occurs when the building or buildings are placed on sites allowing for a higher proportion of build-ration or land to be developed, or where a direct need for private gardens might be found.
4.2. Historical overview
4.2.1. European Development
High-density residential buildings have evolved throughout history due to site sizes being restricted for various reasons. Walled cities developed to increase the chance of survival in war gave rise to high-density development.
The Roman-style courtyard home, known as the atrium house, was commonplace in the ancient world.
This enclosed courtyard developed throughout the Mediterranean region due to climatic conditions, with the high wall providing shade and protection against heat for the mostly year-round family
residence. Later, in Spanish and Northern African regions, Islamic culture continued this tradition with a desire for introspective living.
Today's row housing originated in the Middle Ages. This occurred when town sites became subdivided along the street line.
The golden age of low-rise, high-density housing occurred following the rapid urbanization of Industrial Revolution-era England. Large areas of English cities were covered with two-story row houses of standard design. This led to a rather bleak architectural effect (fig. 4.3) on account of the increased density.
Figure 4.2. London row housing of the XIX century. House type and arrangement
The modern garden home emerged at the turn of the 19th and 20th century, with the growth of English garden cities. This set a model for the European development of suburban "village-style” and row house types.
After the First World War, particularly where social democratic governments came to power, policy called for an improvement in workers’ housing. This modern, functional home design formed part of the ideological background for the German Weimar Republic. At the Deutscher Werkbund exhibition in Stuttgart, 1927, several leading architectural personalities put forward their ideas for modern housing, and most of these were row houses.
Well-known examples of row-house housing estates from the early period of modern architecture, where extensive housing areas were made up of two-story row houses, include the estate planned by Walter Gropius in the Törten quarter of Dessau, as well as the “Römerstadt” built in Frankfurt-am-Main and designed by Ernst May. (fig. 4.4)
Figure 4.3. Housing estate. Römerstadt, Frankfurt-am-Main. 1926 –1930. Ernst May. Detail from location plan and two storey unit layout
The modern movement also adapted atrium houses to developed high-density homes with gardens.
Examples of this are the L-shaped house by Ludwig Hilberseimer (fig. 4.5) or the atrium homes of the 1930s by Mies van der Rohe. Construction of these house types took place not only between the two world wars, but continued into the 1960s.
Figure 4.4. Courtyard house design. Ludwig Hilberseimer. 1931.
Throughout Europe, in the 1950s, financial support was state-initiated for large-scale housing developments. By the 60s, the economic situation, led to the comprehensive and organized development of housing. Low-rise, high-density housing mainly cropped up in England, the Netherlands and Scandinavian countries, with other important developments in West Germany and Switzerland.
Danish architect Jörn Utzon designed the picturesque atrium housing estate of "Kingohouse". (fig.
4.6) Due to the nature of this site and water table considerations, he succeeded in retaining the natural environment.