understood if we consider that there are currently 5,400 people per square kilometre in Tokyo and
3.4 High-rise construction in the future
41 PETRONAS TOWER
3 Technology of high-rise construction Page 56
MESSETURM 259 m
LANDMARK TOWER 296 m
CENTRAL PLAZA 310 m
EMPIRE STATE BUILDING 381 m
JIN MAO BUILDING 381 m
42 TREND TOWARDS EVER-TALLER MODERN HIGH-RISE BUILDINGS
Page 57 3 Technology of high-rise construction
ASIA PLAZA 431 m
SEARS TOWER 443 m
PETRONAS TOWERS 452 m
CHONGQING TOWER 457 m (under construc-tion)
MILLENNIUM TOWER 800 m (planned)
800m (2624 feet)
43 THE MILLENNIUM TOWER – a vision for the 3rd millennium
452 (1482 feet) 2
2
2m
44 PETRONAS TOWERS, KUALA LUMPUR, MALAYSIA
443m (1453 feet)
45 SEARS TOWER, CHICAGO
381m (1250 feet)
46 EMPIRE STATE BUILDING, NEW YORK
259m
47 MESSETURM IN FRANKFURT AM MAIN
(850 feet)
3 Technology of high-rise construction Page 68
48 ADDITIONAL HEAT RECOVERY VIA PILING FOUNDATIONS IN THE COMMERZBANK HIGH-RISE BUILDING ENERGY SAVINGS
Consistent use of the savings potential already available today will indisputably be the most important “source” of energy in the future. Numerous studies have proved that energy savings of up to 80% can be realized in both the private and the commercial sector without any loss of comfort or convenience. “Intelligent energy consumption”
is a term that is increasingly being used in this context. As a result, the foundations for a building’s future consump-tion of energy are already set in the planning stage: the topographical surroundings are of importance here, as is consideration of the prevailing wind strengths and direc-tions, and any shadows cast. An energy-efficient building will be positioned with its “broadside” away from the sun in warmer climates, while every effort will be made to ensure that as much of the facade as possible faces the sun in colder climates. Windows facing the sun should be as large as possible, those facing way from the sun as small as possible (the keyword is: passive solar architec-ture). A rotary building is another conceivable possibility and could be turned towards or away from the sun as re-quired. Particular attention must be paid to thermal insula-tion of the facade. Northern European construcinsula-tion stand-ards are a positive example here, as they specify a thick-ness of several decimetres for the insulating layers. Trans-parent thermal insulation will probably become estab-lished in future, as it not only reduces the heat loss, but can also attract additional heat by allowing the radiated heat to reach the facade without obstruction. Thermopane glazing with a k-value of less than 1 already represents the state of the art today, as does solar glazing with almost 100% reflection of the radiated heat.
Considerable savings can also be achieved inside the building, for instance by using a combined heat and power generating unit instead of conventional heat and power generation, or by using variable-speed forced-circu-lation pumps in the sanitation, heating and air-condition-ing sectors, or by usair-condition-ing energy-efficient fluorescent tubes which require up to 80% less electricity than conventional filament lamps, or by controlling the lights via movement detectors and naturally by ensuring the energy efficiency of every single appliance used in flats or offices, from well insulated fridges to personal computers with low power consumption. Reusing the off-heat from air and water will be a matter of greater importance in the future.
Ideally, our future energy requirements should all be met by regenerative sources.
POWER GENERATION
High-rise buildings are positively ideal for generating power: the huge facades are usually exposed to the sun from dawn to dusk and the prevailing winds on the roof are considerably stronger and more persistent than those on the ground. And these are also the main sources of en-ergy to be used in the future: wind-operated plants to gen-erate electricity on the roof or particularly exposed edges of the facade, collectors to heat air or water and photovol-taic systems to generate electricity on the facades and possibly also for producing hydrogen at a later stage.
Generation of heat via the deep-pile foundations asso-ciated with virtually every high-rise building is a less ob-vious possibility. When the building is complete, water can be circulated through heat exchanger tubes integrated into the pile reinforcements. Due to the feed and return flow of the water, the different energy potential between footing and building can be exploited and the subsoil used as a seasonal or temporary store of energy. One of the first projects of this type has already been realized in the rebuilding of the Commerzbank headquarters in Frankfurt am Main.
CONSTRUCTION BIOLOGY
The more we know and learn about the harmful effects of modern materials and installations on health, the less probable it becomes that future generations will voluntar-ily accept this hazard. Research and industry must there-fore find acceptable alternatives, such as emission-free materials, installations, insulating and isolating materials, adhesives and coatings, as well as avoiding the use of chemicals which give off toxic gases in the event of a fire.
3 Technology of high-rise construction Page 70
49 FULLY AUTOMATED BUILDING SITE CONSTRUCTION PRACTICE
The construction of high-rise buildings will be dominated by four factors in future, namely: time savings, personnel savings and financial savings, in addition to the energy savings already mentioned above.
As examples in Japan show, it is already possible to erect buildings with the help of assembly robots. The required ele-ments are designed and drawn with the aid of computers (CAD = computer-aided design). The computer automatically retrieves all the required (dimensional and design) data from the saved architectural and engineering drafts, as well as from detailed libraries. The parts are then manufactured by fully automatic machines on the basis of these production data (CAM = computer-aided manufacture) and transported to the site “just in time“. Assembly robots pick out the right part in the right sequence, transport it to the assembly point and install the finished element in the right place.