ARCHITECTURAL DESIGN COMPETITION

FOR PASSIVE HOUSE IN BULGARIA

IntexArch, Stefka Ivanova Dipl. Arch., Slavka Gantcheva Student of Architecture, Georgi Iordanov MSc

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Building-Metric-Sheet-44.xls

Semi – Berm Eco Home

The passive house standard is becoming an increasingly beneficial tool in designing the houses of the future. Preserving the environment is now one of the greatest priorities in the construction field with a newfound respect for our sources of energy and materials inspiring many architects to create buildings that are affordable and sustainable.

The driving force behind the design of the Semi – Berm Eco Home was the desire to create a housing solution that is both simple and elegant, that intelligently utilizes the latest available technology, and is sensitive to its surrounding environment. Inspired by the long tradition of berm housing in Bulgaria, we choose to give the concept a modern twist by creating a home that is partially embedded in the landscape. The home has an extremely efficient envelope and a solar panel clad roof that provides the majority of the energy a small household requires. A combination of natural and induced ventilation ensures the comfort of the inhabitants during the summer and a supplementary air to water heating system is in place for the colder winter days. A substantial layer of insulation, in addition to the compressed earth mass that envelops the house, removes the possibility of cold bridges. The construction of the building is monolithic reinforced concrete. The external walls are made of brick masonry that is covered on the outside with an 18cm layer of Rockwool Airrock thermal insulation and varying external finishes.

An important consideration in positioning the house on the plot of land in Lozen village was the predominant wind direction. In this area of the country, the harshest winds come from the northwest and west directions. Therefore, the building deliberately turns away from them with as few glazed openings on these elevations as possible in order to minimize heat loss. In addition, a belt of trees has been planted in the northwest corner of the site in order to redirect the worst of the wind. The garage that is situated closest to that corner provides an additional buffer space between exterior and interior. The main entrance of the building is on the ground level from the north, next to the garage. On that mezzanine there is a storage room and a small bathroom. From that level, you have the choice whether to go right and down the stairs in the semi-embedded first floor or to the left and up the other ramp of the staircase to the second floor. The first floor holds both bedrooms, each with a bathroom attached. The mechanical room where the boiler, the air to water converter, and the controls for the ventilation are located is also on this level. The second floor of the house is open plan to give the impression of a larger space and to allow flexibility in the arrangement of furniture in response to the different needs of the inhabitants. To the east, there is a modest kitchenette beyond which is a bigger area that incorporates both the dining and the living rooms.

Berm homes are based around the premise that past 1m underground, the temperature is mostly constant. The space that is excavated is likely to require less energy to heat or cool because of the lack of significant temperature amplitude. The heat that human bodies as well as equipment such as laptops and other appliances give off can in this case have a greater impact on the overall temperature. With that knowledge in mind, we chose to locate the bedrooms of the house on the first level and partially embed them in the ground. This arrangement provides plenty of thermal mass to contribute toward a stable internal thermal environment. However, it also gives ample space for ribbon windows just above ground level, thereby allowing natural light in as well as ventilation during the summer months.
The main living spaces located on the second level are oriented towards the south where a beautiful glass façade overlooks the back garden. It consists of two high performance triple glazing units with low thermal conductivity, in between which there is space for a greenhouse. The double layering ensures there is little heat loss during the winter months and also maximizes passive solar gain throughout the year. There are remote controlled louvers in place that provide shade in the case of overheating during the summer. In cold weather solar powered heat activated fans move the warm air from the greenhouse into the interior of the building, whereas cold air return vents located near the floor draw the air that has cooled back into the greenhouse. The entire roof of the home is clad in solar panels that generate energy used to warm a 400l. boiler that is sufficient in providing the necessary hot water throughout the year. The energy from the panels can also be directed to a radial floor heating system. Rainwater is redirected off the roof into an external container off the west elevation and is used in gardening or as an emergency back-up water supply.

The ventilation of the house is controlled in order to ensure that fresh, hygienic air is always available in all of the rooms and that polluted or moist air from the kitchen and bathrooms is removed. For every heat vent there is also a cold air return vent. This efficient mechanical process makes certain that there is no great need to open the windows during extremely cold or hot weather. In addition, the staircase shaft is elevated above the roof line. This is particularly useful during the summer when hot air flowing from the greenhouse floats upwards and out of the building, creating a nice air current at the same time.

Overall, the design aimed to create a building that is almost self-sufficient in terms of energy requirements and that makes the most of its location and the natural resources available. The house has been configured with the inhabitants’ comfort in mind but at the same time strives to be conscious of its ecological footprint.