Posthuset Refurbishment Project, Oslo
Posthuset refurbishment project aims to transfer the existing building into technologically and architecturally exceptional structure. The introduced technological innovations have an ambition to turn the building into energetically totally self-sufficient facility based on renewable wind energy with nearly carbon neutral performance and programmable daylight usage. At the same time these technological improvements will shape the distinctive aesthetical features of the architecture.
Energy self sufficiency
One of the main features of the planned improvements is the introduction of wind turbines on the facades of the building. The simple yet powerful devices are planned to cover nearly the whole surface of the building and can produce the amount of electric energy that would even exceed the current requirements of the building. The turbines are light and inexpensive devices working on piezoelectric principle. They would vibrate on even a slow wind speed and are completely noiseless. The advantages of such a system are high efficiency, no maintain costs, reliability and complete safety to humans and birds. The technology is 100% clean and renewable and has no CO2 impact.
The working principle of the generators is the bending motion of a flexible stalk converted directly into electricity, using piezoelectronics. A flexible stalk is surrounded with many embedded piezoelectric discs that are alternately sandwiched in-between rigid backup plates. These piezoelectric structures (toroids) compress and stretch when flexed, converting any motion directly into electricity with no intermediary mechanical generators, transmissions or propellers. A weighted wind-capturing tip can sustain the energy output from a single gust of wind by the continuing oscillation after the gust fades. In light winds the power extraction would be maximized while remaining robust in high winds.
This is a simplified formula that estimates the potential forces generated near the base of a stalk. Assuming a wind force F of 500 pounds, a height H of 100 feet, and a width W of one foot, we can generate a compression pressure C of 50,000 pounds. This is the force available to squeeze and stretch just one of the many piezoelectric discs in the stack.
Piezoelectric materials are predominantly crystals and ceramics, often abundant and economical. Quartz is the most common and well known. First applied in the invention of sonar, the piezoelectric effect is at the heart of many modern technologies, such as radio, cell phones, quartz watches, phonograph needles and the sparking of disposable lighters. Voltage produced by piezoelectrics is proportional to pressure applied. Five hundred pounds of pressure applied to one cubic centimetre of quartz can produce over 12,500 volts (used source of Dick Hodges, Hodges Engineering, Inc.).
In addition of generating electric energy the turbines will greatly contribute to visual renovation of the building turning it to an extraordinary piece of architecture. The vibrations of the turbines will transform the structure into a dynamic, ever changing edifice, without one fixed form. The kinetic effect will be enhanced with reflected sun light on the surfaces of the hundreds of turbines during day and individual LED lights of the turbines during night.
In order to maximize the utilization of daylight as the main source of light during day and improve insulation an adaptive sunshade system is introduced. The metallic hexagon shades system within double-skin glass facade can be programed to open and close itself in response to the internal temperature and illumination of the building, creating a comfortable working environment inside.
An example of similar system that is practically sued is Adaptive Fritting™ developed by The Adaptive Building Initiative. Adaptive Fritting™ is an integrated glass unit with a custom moveable graphic pattern that can modulate its transparency to control transmitted light, solar gain, privacy, and views.
While conventional fritting relies on a fixed pattern, Adaptive Fritting™ can control its transparency and modulate between opaque and transparent states. This performance is achieved by shifting a series of fritted glass layers so that the graphic pattern alternately aligns and diverges.
Glass fritting is an established architectural treatment for passive solar control; Adaptive Fritting™ imbues this treatment with the expanded functionality of movement. The benefit is twofold: It provides architects with a new design element that is a familiar part of their vocabulary, and it increases the performance of standard fritting by creating a customizable shading scheme while preserving transparency where desired.
Improved heating system
New micro-ceramic infused fleece radiant heating system can be implemented to improve heating efficiency and substantially reduce CO2 emissions. The system distributes heat using the electromagnetic spectrum with almost 100% energy efficiency. The fleece helps to minimize energy waste and create large cost savings. With air being warmed indirectly an ambient temperature is achieved as heat radiates from objects inside the room. A room is heated more rapidly and efficiently than conventional systems by heating objects rather than circulating air. This creates additional benefits for allergy sufferers with a dramatic reduction in the movement of allergens.
The fleece neither emits microwave radiation nor causes atmospheric dehydration and is extremely lightweight, it can be installed behind plaster board, within wall and ceiling cavities, under floors, behind wallpaper, stuck to the wall and painted, free standing or hung like a picture. Temperature is controlled using a conventional thermostat.
Other benefits of the system include: low DC current avoiding 50 Hz radiation, steady warming of objects and surfaces, anti-mould heating that keeps interiors dry, low maintenance costs, possibility to be used with solar, wind and other green technology.
To enhance ventilation of building the decentralized ventilation system is combined with natural shaft ventilation to form a hybrid, more flexible system. The central space of the building, between the two towers is partially cut for all office floors thus forming a central shaft/atrium for air flow.
In summer the building can be ventilated using up flow displacement ventilation. Air entered through exterior windows in each room before flowing into the shaft through transfer units. The air would rise within the atrium and exit through the high level windows or vents at the top of the space. The large difference in height between the low level entry of fresh air and the exit of warm air through the atrium would create a large buoyancy effect which draws air through the building.
The system can also be very dependable during winter, because the wind-protected location inside the building would prevent the exhaust air from cooling too quickly. Vents or windows in the atrium can be used to bring fresh cold air into the building as well to exhaust the hot polluted air. The air would mix naturally in the atrium owing to the convective flow patterns which would develop in the space.
Expansion and area efficiency
In addition of ecological sustainability the refurbishment project aims to be economically sustainable as well. A horizontal expansion is introduced towards the plaza area. Expansion is not dependent on the existing construction and has its own column system. The expansion will increase floor area for office storeys by approximately 30%. The enlargement will also further amplify the visual perception of the building as two separate structures.
New ramp system is incorporated in the project to connect Posthuset building to central station and plaza with direct access to mall on ground and first floor and restaurant on second floor respectfully.
Area efficiency of the office floors are increased in terms of improving their human capacity and circulation by combining open plan office spaces with semi-cell type ones.