The volumetric solution of the shelter is entirely related to the situation, the specific characteristics of the mountain and the energy concept of the building. In order to fit the shelter into the natural environment, a look of massiveness and similarity with a short scale is achieved through the use of only one material for the walls - gray fibro-cement sheets with a linear texture located at different angles.
Contrast is provided with a stainless steel door and roof cover in yellow to make the shelf visible and recognizable from a distance, and to enhance its function of a landmark and repertoire in the middle. For night shelter recognition, it is proposed to use innovative solar cement boards to emit blue-green light at night without the need for electrical power.

The shelter is a module, composed of small elements and is planned to be built entirely in place. For the construction of larger structures, the module can be multiplied by modifying (dropping the door) in the direction of the long axis of the building. Thus, it is possible to obtain a larger room or two rooms with a common foyer depending on which side the additional module is placed on.
LIGHT IN THE DARK CEMENT It is an innovative energy-efficient material created by adding light-sensitive particles and changing the microstructure of traditional cement, allowing it to absorb ultraviolet rays during the day and to emit light at night. This technology also works in cloudy weather, and the material will retain its light output for more than 100 years. With luminous cement, whole structures can be constructed or used only as finishing of a finished element. By placing luminous cement panels around the entrance of the shelter, it will be illuminated and recognizable at night without the need for electrical energy.

FEATURES OF FIBROSIMMER PLATFORMS Fiber cement is a widespread ecological material with low energy input and high resistance to atmospheric influences. Fibro cement boards are light and 8 mm thick (10 mm). Innovative and attuned to the aesthetics of the building is the Equitone Linea series of Eternit,

Which represents 3D flat-line texture. Changing the angle of fall of sunlight during the day will give the facade a different aspect. Fibro cement boards are not recommended to be used for roof coverings at altitudes above 1700 m, so a stainless steel sheet is selected for the shelter roof.

Multilayer insulation originates from space technologies for light and very efficient shuttle insulation. The material works on the reflection principle of the deep infrared spectrum (similar to the low-emission coatings of the glass panes) and, although very thin, allows excellent insulation qualities. The same principle applies to the life-saving foils that every good mountaineer and mountain saviour carries with him.

Experts from the Fraunhofer Institute (Germany) have proven that the Aluthermo Quattro market product accounts for nearly 20 centimetres of mineral wool insulation. This innovative product for the construction sector is gaining attention in France, Germany and Denmark, and the shelter project allows for the first time to be used in Bulgaria.

Compact heat recuperator that allows controlled ventilation with up to 85% heat recovery. Air exchange keeps a healthy microclimate in the room and prevents moisture build-up and mold formation. When removing the warm air out, a ceramic element takes off and stores its heat. An installation of two recuperators is planned to be connected in a dialog mode - while one unit fills fresh air, the other will take the warm stagnant air out. Ventilation of the shelter is provided without the necessity of ventilation by opening windows, which would result in the loss of valuable heat in the winter.
In the interior of the shelter is used entirely wood - wooden bearing elements and lining of solid wood panels. The room is bright and cozy. Contrast is sought with the exterior and creating the impression of entering the massive "rock" volume. The connection between the exterior and the interior is realized through the discreet presence of the yellow color and the interior through the two yellow rope ladders and the clock mechanism.
The shelter consists of two rooms - an anteroom and a rest room. The antechamber is designed to keep the heat in the main room when the doors are opened. In it there is a map of the locality marked with the closest location, neighbouring sites, itineraries and others, as well as a dashboard with useful information about Vitosha, the local flora and fauna. There is also a device for direct connection to rescue services in case of need.
In the rest room there are six double beds, located at a height of three, accessible via rope ladders. Rope ladders are preferred because of their small weight and the ability to unhook the snares and retract if they interfere at a time. There is one more bed opposite the antechamber, which can be transformed into a bench by folding and slipping depending on the needs of the people in the shelter. Thus, the shelter capacity is 14 sleeping places or, by transforming one bed into a bench, 12 sleeping and 3 seating. In front of the bench there is a table that is folded and retracts in parallel to the wall. Next to the bench and the table is one of the windows revealing the view of Kopitoto and Sofia. Above the bench is a cabinet for materials for first medical care and shelves, where it is possible to put special maps, brochures and books related to the flora and fauna of Park Vitosha. The shelf is equipped with USB plugs for charging small electronic devices.
As part of the shelter equipment, a meteor station, GPRS module and router are offered on the roof. Thus, visitors to the shelter will have access to the Internet via Wi-Fi and access to weather information.

For clarity and trouble-free use of shelter equipment on wooden boards are gravure explanatory inscriptions and symbols.

The power supply to the shelter is provided by a photovoltaic panel placed on the roof above the door. Rechargeable batteries are provided to store the generated but unused electrical energy that is placed in the space between the atrium's ceiling and the roof. In the rest of this space, a lockable cabinet for storage of equipment on the bed is designed on the bed.

The interior features energy-efficient LED lighting with presence sensors.

Exterior lighting is not necessary as the area around the entrance is illuminated by solar cement panels. However, a pulsating light signal for fog guidance is provided.


In the design of the project were taken energy efficiency solutions, which besides innovative for Bulgaria were, in one way or another, proven. The project makes it possible to prove them locally and can be an excellent example of innovations in construction, both at national and regional level. The project team is committed to designing and implementing such high-mountain projects and relies on their experience of successfully planned and realized projects.