ARCHITECTURAL DESIGN COMPETITION

FOR PASSIVE HOUSE IN BULGARIA

Nikolay Todorov Dipl. Arch.

(311 - user rating)

Building-Metric-Sheet-65.xls

Narrative Description of the Design

1. The Approach
What is a Passive House?

“The term passive house (Passivhaus in German) refers to the rigorous, voluntary, Passivhaus standard for energy efficiency in a building, reducing its ecological footprint. It results in ultra-low energy buildings that require little energy for space heating or cooling. Passive design is not an attachment or supplement to architectural design, but a design process that is integrated with architectural design...” – Wikipedia says.
“Built according to this standard the need for heating will be reduced by 80-90%. compared to conventional build, which has an average heating demand of 150kWh/m2a, these homes need only 15kWh/m2a.”
“It relies on all the elements: • Insulation • Window Insulation levels such as triple glazing • Thermal detailing • Air tightness • Mechanical heat recovery • Appliances use • Solar Gain, to work together and to interact together. “ – are some other quotations.
“Passive House is a specific approach to energy efficient homes, originating in Germany…” – etc.
Well, that is the standard, but is the idea new or old? Can we find some origin, samples of similar traditional buildings? Where to look for – in history, in geography? What are varieties in ethnic or cultural heritage in home construction? And what is the usual shape of such a house? Let us take a look around. Where to start from – probably the coldest place in the world?
“An igloo (or snow-house is a type of shelter built of snow, originally built by the Inuit. Although igloos are usually associated with all Inuit, they were predominantly constructed by people of Canada’s Central Arctic and Greenland’s Thule area. Other Inuit people tended to use snow to insulate their houses, which were constructed from whalebones and hides. Snow is used because the air pockets trapped in it make it an insulator. On the outside, temperatures may be as low as −45 °C (−49 °F), but on the inside the temperature may range from −7 °C (19 °F) to 16 °C (61 °F) when warmed by body heat alone.” Does it remind you anything? And the shape is circular or rather semi-spherical …
“Tepees are the transferable cone shaped house of Native Americans who move to live for hunting. The house is 3.5 to 5.5 meters high and there is the exhaust pipe in the center of the house. The house is covered by buffalo hide.” We move to the South.
“Gel (also Ger, Yurt) is the Mongolian transferable nomad house. The main 2 poles in the center support the house with the framework. They cover the framework with the white cloth filled with wool and hair of the domestic animals. During the severe winter, they make double cover on the ceiling.”
“Roundhouse dwellings, made of wood and straw, were built in Europe, (Celtic Wales) by the time of Iron Age.” And moving further south, named depending on the region, throughout Africa there are many samples of traditional homes, usually constructed using wooden frame or built with stone, mud and daub, and thatched with straw.
“Toukoul or Tukul is a typical cylindrical house with conic straw roof, still used in many rural areas in Ethiopia, Rondavel is traditional South African house made of stone masonry round wall and conic shaped thatch roof. It can be found in the countries of South Africa, Lesotho, (where is also called Mokhoro), Swaziland, Botswana and others.”
What do those homes and houses have in common with our Passive House? First of all - insulation, natural local construction materials, most of them – round shape, which means less thermal bridges, and some of them similar energy efficient heating or ventilation. So, taking inspiration from the past and today around the world, our design aims the future, applying the modern science standard for Passive House in Lozen, Bulgaria and creatively transforming the general idea (of energy efficiency) into a beautiful but inexpensive home. I have seen hundreds of Passive House designs that look alike – box shape volume, simplified two slopes roof, big glassed wall (supposedly facing south) and some Solar collectors fixed on the wall or attached to the roof. However efficient such houses might be, we try to avoid that image.
2. The Design
A) Site and Orientation

We have chosen North-South direction along the access road in order to situate the building and its premises according to the correct orientation for optimal sunlight gain and considering the rooms function. This way the main entrance (access) faces East to the street side, which is preferable solution (taking into account prevailing North, West cold winds typical for Bulgarian winters). Our entrance is sheltered from the winds. Bedroom1 is also looking to East. The Living Room is facing South, and Dining room – South and West. Master Bedroom, Bathroom and Kitchen are orientated to the West, to the larger open terrace with pergola and the deeper green area back yard. Except for the small store window North walls are blanc, without openings. The central hall with spiral stairs is in the focus to optimize communication between the rooms. Total site area amounts to 1546m2 and the house (Ground floor) built up area is 140m2, with an option of constructing First floor Lobby and Bedroom on area of 40m2, depending on the budget. With that we complete area requirements.
B) Structure and Function
Our design offers timber frame structure for walls, floor and roof with insulation of mineral wool (rock wool) and layers providing water proof and vapor insulation. From inside all walls are finished with double plaster cardboard sheets, (KNAUF type), which also serves as fireproof coating. Outside coating of the external walls might be also waterproof plaster cardboard sheet, or plastered waterproof plywood sheet, or finished with plastic cladding. As it is a preliminary design we allow for options. Total outside walls thickness is 33-37cm depending on materials applied. Because the design is more or less symmetrical, most outside walls (and inside ones), floor and roof could be prefabricated SIP (Structurally Integrated Panels), which reduces the cost and saves construction time. Three of the outside walls (facing south) are used as Thermal Mass and constructed from bricks (or concrete blocks) and overall glassed from outside. We recommend using triple glass windows without thermal bridges for the house.
The function is clear and simple (see the plan). The Living room is open to the Dining room (separated by the bar only) and communicates with the Kitchen through it. There is optional small swimming pool provided to the green area, which may contribute to the total comfort.
C) Energy Efficiency
As it was already mentioned we apply Passive House standard to our design. We provide enough insulation, triple glazing for windows, enough air tightness, mechanical heat recovery, appliances (and body heat) use and solar gain for our house. Our energy need is less than 15kWh/m2 a year. In addition our design eliminates Thermal bridges, provides Thermal mass walls, uses Solar Water Heat collectors, Rainwater collectors with treatment used for the swimming pool, waste water treatment for secondary use etc. This way we maintain high comfort level and reduce the expenses. Additional cost reduction comes from use of SIP prefabricated walls, floors and roof structure. All electrical, water supply and waste pipe installations could also be prefabricated and imbedded into the SIP structures.
D) Beauty
As it was said our design creatively transforms the general idea (of energy efficiency) into a beautiful home with elegant structure and elevations.