Solar Active House - the building concept & the equipments

In this article the architect of the house Arch. Georg W. Reinberg describes the aims and the building concept as well as the equipments in the Solar Active House, which has been build in St. Veit in Austria.

 

Solar Active House

 

(Author of the paper: Arch. Georg W. Reinberg )

 

Previous history

 

 

Already 1999 the author has won an invited competition for the development of a solar industrial park in St. Veit in Carinthia. As a result of this competition the building of the Company ‘Sonnenkraft’ was implemented. The industrial park has not been completed, but the office building. Further on the author could win an invited compe­tition for a solar research centre at the same site, which is still in planning stage. In this context he was asked by the same company to develop a new building concept, which reinforces the use of active solar gains. This initiative on the part of VKR Group (to which belongs the company ‘Familie’ and the both companies ‘Sonnenkraft’ and ‘GREENoneTEC’ in St. Veit) occurred out of a Europe-wide survey, which showed, that solar building and the use of alternative energy has an extremely positive conno­tation. Since the products of VKR lie largely in the range of the use of daylight and alternative energy, the idea occurred, to build model houses, which are trend-setting. They accord to the standard of 2020, provide a high living quality and use the energy of sun. At the same time the author has a lot of positive experience with the concept of solar architecture, particular from the projects ‘Gleisdorf’ (an office building for the company AEE Intec and row houses) which were completed 1999 respectively 2000. In these buildings sixty percent of the energy gain was covered by solar energy. Their very positive performance data fall below the energy consumption of the passive house.

 

In the start-up phase for the development of the carinthian projects, the concept ‘Solar Active House’ was born, which emphasizes the increased application of solar technique. The building itself was developed and accomplished indepen­dently from the other model houses of the Europe-wide Solar Active House program of the VKR Group. The following aims were set for the Solar Active House:

 

Aims:

 

In accordance with the high ethical claims of the new building owners the ‘Solar Active House’ idea works with aboveboard concepts, which don’t pretend some­thing, but are oriented towards highest effectiveness. The adequate attitude of this architecture relies on the fact, that out of the new thinking and techniques a new, independent architecture is to be developed, whose especial aesthetic values exist in good formal answers to the ecological questions.

This means, that in this concept neither ‘new technique’ is attached to old, traditional architecture nor the ecological questions are answered on a formalistic and super­ficial or even feigned manner.

 

The principles for the Solar Active House were:

- Low energy consumption: as well through very low energy consumption for the handling and the air conditioning (included cooling) as for the building process, for the preservation and for the recycling.

- Low environmental burden: through the use of preferably ecological building materials and through the application of solar energy as preferably exclusive energy source.

- Highest living quality: through optimized use of daylight and first-class architecture.

- Healthy room climate: best quality of internal air through advantageous biological building materials.

- Inclusion of the environment: a smooth transition between indoor and outdoor shall be allowed through an openness and transparency of the buil­ding, to adapt it to the specific place and its climate and to make the specific qualities of the environment (sunlight, outlook etc.) accessible.

- Affordable for the average consumer: the final price of the building should be so low, that the additional costs compared to a conventional low energy house can be reduced through the lower costs of energy in the next 10 to 15 years (at the spon­soring conditions, which are effective in Austria).

 

To satisfy this claim, the architecture of the single, respectively row house again has been rethought in the initial phase to this project. Through countless variants an optimized basic concept was found. This concept has been developed by architect Reinberg together with the companies Sonnenkraft Österreich/ General Solar System, Solar Cap, AEE – Institute for sustainable Technologies (AEE Intec) and in the phase of accomplishment by the company ‘Griffner Haus’. The pictures show the model house, which has been completed in summer 2009.

 

Building Concept:

 

In the draft period it was important for the architect, to apply the new techniques in each case at the optimal position and to use the concept and the quality of solar strategies itself as elements of architecture.

 

In this way the building takes up a clear stance to the sun and indicates very directly the orientation to south and north. In the case under consideration the building ope­nes fortunately towards a beautiful perspective to the south situated Alps. At greatest possible compactness the building optimizes the south face (as possible solar gain area).

 

For the solar utilization the ‘concept’ can be described with following examples: the potential of the south side is used differently according to the single solar strategies.  For instance the same south orientated surfaces, which gain the winter sun in a passive way, are available for the electricity generation in summer. As the PV-elements would only provide very few electricity in winter, but in summer have the greatest production potential, they are oriented to the summer sun (flat inclined). Additional they are levitating, because the production of the PV elements is dependent from the temperature of the elements and the free ventilation is consider­ably conductive to increase the production. The PV elements are not directly one upon the other, but displaced to the north to avoid mutual shading at forenoon or afternoon. The solar windows are largely arranged vertical – orientated to the low winter sun – because they shall deliver only the warmth of the winter sun. The fanlight windows in the south and the windows which lie at the highest point of the living room in the north bring the light from the highest points of the building in the interior and make the best use of the daylight. In summer – when in our climat daylight is available abundantly – this fanlights deliver only diffuse sunlight, because they are lying in the North respectively are shaded completely.

 

Through the chosen alignment (architecture) of the PV elements and the south gla­zing the building concept uses the changing stand of winter- and summer sun without having to move itself or it’s elements: the winter sun reaches into the building and the direct summer sun is entirely absorbed by the PV elements.

 

The thermal solar collectors are integrated in the building because their function is increasing with the warmth of the surrounding. The number of collectors varies according to the requirements of the inhabitants and according to the location. In the case under consideration the solar radiation values are relatively good (Carinthia, 600m over sea level).

 

It is constitutive at the development of this type of house, that it is not reducible to a mere technical concept which reduces energy limits. In this concept architecture itself is used to optimize the technical systems in a way, that their production can be used fully. Cost reduction in the building, altogether a better ecological balance. At the development of this building type it was paid attention that it can not only be used as single family house, but also as row house (compacted low rise building).

 

Building Equipment:

 

The basis for the application of the building equipment is a very good building envelop to keep the loss of heat in winter as well as the loss of coolness in summer low. This building envelop represents almost the Passive House standard, but not in each detail with equally high claims. The building equipment uses exclusively proven products, which are unexpensive. The strategically applied technique compo­nents tend to an energetic all-season self-sufficiency of the building and a long term CO² neutrality.

 

Constitutive elements therefore are:

 

- The passive solar utilization is optimized in so far, that overheating can be avoided through good overheat control. So the usual limits for the passive solar utilisation (and therefore the daylight guidance) can be exceeded considerably. With this improvement of the winterly passive solar gains, the solar gains of the thermal collec­tors for the heating can be enhanced.

 

- pre-assembled compact system: The system „Solar Compleet“ is consisting of circa 25m² thermal collectors, one accumulator and a heat pump. Accumulator, heat pump and all faulty wiring elements are prefabricated and are delivered altogether in a box. Furthermore the window aeration is provided with a prefabricated switching system and the mechanical ventilation is delivered as compact application.

 

- Generation of electricity: 35-40m² standard PV elements are inserted with the aim to cover the annual power requirement of the building. The PV elements also make shadow in summer (double function).

 

- Controlled ventilation:

 

a) Mechanical ventilation with recovery of air infiltration: a compact device with cross flow heat exchanger which is speed-controlled via CO² Sensor

 

 

or alternatively:

 

b) Automatically controlled window-opener: the windows are opening and closing automati­cally depending on the concentration of CO₂ and the temperature of the internal and external air. This variant has been developed to reduce the aeration to the hygienic extent. Because the standard air change of the 0,4 or 0,5 fold at a useable living area of circa 150 m², a two-storeyed living room, only three or four inhabitants and a frequently absence of the whole family during the day or on week­end would cause an unnecessarily high rate of air exchange, it is due, that with this system of controlled window opening, considerable loss of energy (through too much aeration) can be avoided.

 

Furthermore with this method the mechanical systems can be reduced (a more ‘passive’ handling and therefore reduction of the consumption of electricity). Over a low energy PC with a flat screen the inhabitants can adjust the demanded indoor climate individually and overheating can be avoided. The automatic control enginee­ring is produced by ‘WindowMaster’ and is proved multiple and since years in office buildings. The system of window aeration is tested in the Carin­thian model house in comparison with conventional mechanical aeration.

 

- The heating takes place through static radiators. They are integrated in the loam rendering as heating surface as well as in small areas as floor heating. Aligned to the solar heating the heat distribution takes place on a very low level and the spread between flow and return flow is only 8°. The radiators allow an individual choice of temperature for each room.

 

- The overheat control is effected through complete shading of the south façade by  the PV elements and additional with exterior blinds, which are part of the window frame. The control of the blinds is bounded into the control system of the auto­matic window opening. Furthermore simple summer night ventilation is pos­sible via the window controlling. There are windows for the discharged air on the highest point of the house in the north.

 

- Mood lighting via daylight: through the exterior blinds and the free control it is possible to chose the mood of the light in the building.

 

- A heat pump optimizes the different systems (thermal collectors, accumulator, earth collector) and uses the air as heat source. So it becomes possible to drive the solar cycle also under circumstances, where the temperature in the lowest area of the accumulator falls below the traditional limit. The sole can be preheated by the air- heat-exchanger before it enters the WP-evaporator. The efficiency of the thermal collectors is enhanced over circa 25 % („Solar Booster“).

 

- The fresh air supply (in the mechanical ventilation variant) is effected through a circa 35 m long earth-air channel (pre-cooling in summer respectively preheating in winter).

 

- Earth-tube collector: surplus from the thermal collectors is fed into an earth-tube (circa 150 linear meter sole cable as flat plate- or foundation trench collector below the building). It is used through a heat pump (‘energy-swing’). Thanks to an earth temperature which is increased a few degrees, times in which the heat sources are normally marginal, can be bridged without having to come back to a heating with electricity. Thereby an all-season solar handling shall become possible.

 

- Controlling: the whole controlling is effected through a central, energy saving computer.

 

- Dishwasher and washing machine are provided from the thermal (solar driven) accumulator, whereby a considerable saving of electricity can be gained.

 

- The optimized use of the daylight allows further considerable savings of energy.

 

- The supply with warm water is effected through a heat exchange principle, so that no warm water is stored. The water is heated by a ‘flow-through system’ so that the warm water is always fresh and hygienic clean (no problems with ‘Legionella bac­teria’ are possible).

 

- The solar reserve of (available façade and room for collectors) allows an expansion of the system with new – in near future foreseeable – solar techniques as: thermal collectors for the cooling (a cooler unit, which works with absorption and dispenses the coolness over the wall areas, thermal collectors for the production of electricity, integration of weather fore­cast in the controlling system and so on).

 

- Prefabrication: the very high degree of prefabrication of all building equipment sys­tems allows economical costs of production, a guaranteed error-free assembly and an optimal gain.

 

 

Materials:

 

The building in the case under consideration has been built from prefabricated wooden wall elements (which have a thickness of circa 40 cm). These elements consist of a plasterboard construction, which is filled with pulp. Inside there is an additional insulation layer (5cm) which is also filled with pulp and which serves as running of cables. Inside the room this layer is closed with a plaster base for loam plaster (with integrated heating).

 

In the north, east and west the outside walls are boarded with wood. The south façade is used either for the passive and active solar gains (by using solar windows which, in the heating period, gain more heat for the house than they loose), or they are covered with façade panels. These façade panels can be changed optionally through col­lectors. They can be adapted individually and therefore are open for other systems.

The windows are from a new developed type which were used here the first time (VELFAC Helo). The advantage of these triple glazed windows lie in the fact, that the frames are very thin and therefore the valuable reference between the inside and the outside gets enhanced through more transparency. Furthermore the sash, which are pivoting to the outwards allow an eminent effective aeration. In the highest area the sash is pivoting inward. The model house in Carinthia has been built as pre­fabricated house but the system is open for different versions of completion (for instant in solid building or in plywood construction).

 

 

The Model House:

 

The living area of the model house in Kraig in Carinthia is 150m².  The living room has two levels and provides a unique living comfort. This living room is characterized by high lying skylights and fanlights in the North and therefore has high daylight qualities. In winter it is directly and fully illuminated by the sun. In summer the illumination through the sun can be limited to diffuse day light, there is a possi­bility to control it individually in summer as well as in winter. In the ground floor, next to the living room there is a small bathroom, a room for the building equipment, the ante­room, a kitchen and a working room. A gallery leads to the upper floor with three rooms and a bathroom.

 

This built variant can be adapted to other demands (more or less rooms, more bath­rooms etc.) Several ground plans are available.

 

The Solar Active House in Kraig (near St. Veit) in Carinthia was built in the context of a major campaign of the VKR Holding: The VKR Holding has initiated the building of eight model houses, whereas the building in Carinthia was developed and realized independent from this other buildings. The speciality of the Solar Active House in Carinthia is that for the housing system a specific architecture has been developed. The Carinthian ‘Solar Active House’ deviates in some points from the original architectural planning. For example the PV-Elements, the solar thermic collectors and the accumulator have been completed smaller than originally planned by the architect.

 

In the context of these buildings the Solar Active House in Carinthia will be measured and scientifically evaluated.

 

The model building in Kraig is acquirable after completion of the measurements 2011 for ca. € 333.000 Euro.

 

More information:

www.reinberg.net

www.solar-aktivhaus.com

 

 

CONSTRUCTION SIGN BUILDING-BLACKBOARD

 

Architect                             Architekt Georg W. Reinberg, Wien

                                             architekt@reinberg.net

Building owner:                 Sonnenkraft Österreich Vertriebs GmbH

Consultant statics:            DI Johann Riebenbauer, Graz

Building physics:              DI Thomas Zelger, IBO Wien

Simulation:                        AEE, Intec, Gleisdorf

Building equipment:        Sonnenkraft Österreich/General Solar System und Solar Cap, St. Veit a.d. Glan

Prefab house company:  Griffner

Planning period:               2007

Construction period:         winter 2008 – summer 2009

 

 

 

 

 

 

 

Statistics:

 

Estate area                         636,00 m²

Building area                     116,00 m²

Cubic content                    741,00 m³

Useable living area          150,00 m²

Solar collector                    24,00 m²

Photovoltaics                     37,00 m²

Accumulator                      1000 l

 

 

Further involved companies:

 

Velux Austria, Wolkersdorf

Velfac A/S, Horsens DK,

Window Master, Bad Oeynhausen, BRD

Kioto Photovoltaics, St. Veit an der Glan

drexel und weiss, Wolfurt

Bio Baa und Verputz, Klagenfurt

Leopold, Spengler und Dachdecker, Feldkirchen

Solaris, St. Veit an der Glan

F & F Haustechnik, Poggersdorf

Pro Lehm, Fehring

Gappitz-Bau, Pischeldorf

Malerei Bierbaumer, Lavamünd