Adaptive cold and permafrost home

. Severe natural and climatic conditions, remoteness from industrial centres, and poorly developed infrastructure in the northern (Arctic) regions strongly affect the life and comfort of the population. In such conditions, the construction of a maximally habitable, available for construction, energy-efficient and climate-adaptive dwelling house is in particular demand. The main criteria for creating an adaptive house were: 1) cost-effective construction; 2) minimum heat loss during exploitation; 3) maximum use of available and local materials; and; 4) adaptability to climate change. The adaptive individual house was created taking into account many years of experience in the design, construction and operation of residential buildings in the Far North and the peculiarities of the arrangement and way of life of the northern peoples. In the process of work on the project, the main principles of choosing building materials and constructions, design and construction of an individual house in the conditions of the cold climate and permafrost were generalized and specified. It is necessary to note, that projects of adaptive houses should be developed taking into account climatic conditions of the area of construction and logistics as well as modern requirements of resource and energy saving, ecological and fire safety. Such designs should be tested in Central Yakutia, and then replicated for northern and arctic areas.


Introduction
In Soviet times, the entire Far North, covering more than 60% of the territory of modern Russia, was, in fact, an experimental ground for the development and testing of the principles of residential building design and the improvement of a wide range of building materials and technologies for cold and permafrost conditions [1].
In the volume-planning solutions of mass apartment construction in the 1960s-80s of the, the characteristic feature is the widest possible enclosure with a minimally indented building perimeter, which provides the building with great thermal inertia [2]. Structural features of that time also include the provision of ground floors with infrastructure with the corresponding communications. In addition, it is recommended to connect all the infrastructure elements built into the buildings with warm passageways providing access to pre-schools and schools. Innovations in the projects also include the use of a covered, warmly landscaped and landscaped courtyard between two meridional-oriented residential buildings. The high comfort of living is ensured by a well-developed social infrastructure with a full range of services for residents.
In subsequent typological experiments [3], it is of scientific and practical interest to use the buffer principle by creating cold and warm atriums horizontally and vertically. In winter, cold atriums are allowed to maintain temperatures as low as -5°C, allowing children and adults to participate in winter activities from the comfort of their own homes. Atrium spaces with well-developed infrastructure not only act as buffer zones, but also significantly improve the quality of life by providing comfortable recreation for adults and children.
It should be noted that in the twentieth century not all ideas and innovations in the field of architecture received practical implementation in the mass high-rise construction. Today, the current direction of scientific research is the further development and implementation of innovative design and technological solutions in the field of low-rise and individual construction, especially demanded in the areas of the Arctic and the North, remote from the industrial centres.
This article discusses the principles of selecting the optimal volume-planning solution, building materials, and structures when designing and constructing an individual house for the cold climate and permafrost conditions.

The origins of the development of northern housing
For the first time, the everyday life and peculiarities of life of the northern peoples of Eastern Siberia are more fully described in the V.L. Seroshevsky's ethnographic study [4]. The harsh climatic conditions forced the Yakuts living along the numerous rivers of the Lena Basin to develop a special way of life to survive. In this cold land, everything was subject to the law of nature in accordance with the main occupation -cattle breeding, which required constant relocation (migrating) depending on the season to provide natural forage -hay for the cattle. Each household spent the winter at a winter homestead located among the meadows, close to the hay stock. The main requirement for a winter homestead was to be protected from cold winds, the presence of a forest and a body of water. The basis of the winter dwelling was a wooden yurt-balganza, a warm building was set up, choton for the cattle. After a long winter, with the onset of warm days, the family and all their cattle moved to the summer pasture, where there was a summer dwelling -sayylyk with all the outbuildings. By autumn, the cattle had been moved to temporary pasture, otor, where they grazed until the first snowfall. As a consequence, the dwelling was arranged as a light structure -urasa.
Architectural and spatial organisation, technologies and materials of traditional Yakut dwellings -yurts-balagan and ursas are considered in detail in [5]. The yurt-balagan is a fairly simple construction in the form of a truncated cone with walls of sloping logs, a supporting frame of four poles connected with beams, on which a roof of thin trees is placed. To preserve heat, a 60-70 cm layer of earth was placed on top of the sloping roof, the sloping walls were covered with a layer of clay and cattle dung mixture, and an earth mound was arranged outside the house. The source of heat was a cooker -kamelek, This was an earthen structure with an open front and chimney. This kind of cooker heated the room relatively quickly when it was burning, but retained little heat after the end of burning, so it required a constant supply of fuel (logs) on cold days. To save heat in winter, the dwelling house was combined with a livestock building, where the positive temperature is maintained due to the natural heat of the animals. Sometimes, several houses were built on the homestead, and the transition to the summer house had purely hygienic meaning -cleaning, airing, and destruction of insects in the winter dwelling. The advantages of the ancient technology of building a house in the form of a truncated cone include sufficient roundness of the outer shell, allowing for natural additional heat insulation due to accumulation of snow cover.
Modern human everyday life in villages where cattle breeding has been preserved, the way of life has remained almost in the old style, but with modern constructions. The living conditions in the countryside are very different from those in the cities. In the city, as in relatively large settlements, most people live in comfortable flats and particulary all have holiday plots with summer houses, i.e. nomadism in the new sense has been preserved. Some difficulties appear for those people who have built a huge cottage or homestead on a private plot in the context of a city or a settlement. Children grow up and, as usual, leave the nest, parents are left alone in the huge penthouse, and the cost of heating energy increases every year.

Principles for selecting building materials and structures
The natural and climatic conditions of the Republic of Sakha (Yakutia), further Yakutia, are characterized not only by the presence of permafrost, but also by a sharply continental climate with freezing winters down to -72°С and hot summers up to +38°С, a sharp difference in the outside air temperature in the spring and summer period up to 40-60°С [6]. The heating period lasts 8-9 months a year, sometimes all year round (365 days), e.g. in the Arctic village of Tiksi.
Thermal engineering calculations show that the best option for Yakutia's climatic conditions are multi-layer building envelopes consisting of load-bearing, thermal insulation and cladding layers with sufficient energy efficiency (Rотр ).
Materials with a low thermal conductivity coefficient can be recommended as an insulating layer, taking into account operating conditions of the order of 0.03-0.07 W/(m×C). These materials include foamed polystyrene, mineral wool boards, ecowool, vermiculite, expanded clay, cellular glass, etc. The requirements for building materials and constructions are higher in terms of ecological and fire safety. In recent years there has been increased interest from the scientific community in this crucial issue [7][8][9][10].
Criteria for the selection of load-bearing materials in low-rise construction may be, first and foremost, fire safety and environmental friendliness, sufficient strength and crack resistance at low density, increased frost resistance, reduced thermal conductivity and high specific heat capacity.
Thermal inertia is used to assess the thermal resistance of a building envelope, which describes the ability of the envelope to maintain a relatively constant internal surface temperature with fluctuating heat flux. Building code requirements classify building envelopes into solid (D > 7), medium-sized (4 < D ≤ 7), low bulk (1.5 < D ≤ 4) and lungs (D ≤ 1.5). On the other hand, the greater the thermal inertia of the envelope, the higher the thermal storage capacity of the envelope.
The degree of massing of enclosures is determined by their thermal inertia: where Silayer heat absorption coefficients (at 24 hours period), W/(m 2 ×°С). The heat absorption coefficient (U-value) is a value that describes the heat absorption of a material.
Thermal resistance of a homogeneous construction R, (m 2 ×°С)/W, calculated by: where δ -layer thickness, λ -is the heat transfer coefficient of the material, W/(m 2 ×°С), Taking into account the conditions of the construction area (in our case Yakutsk, Table 1).
For the comparative analysis of single layer wall constructions, we choose efficient lightweight and cellular concretes with the same density 500 kg/m3. The thickness of a single layer wall of different materials is set to 0.4 m. Record the calculation results in table 2. As can be seen from Table 1, a single-layer arbolite wall has the highest thermal insulation and heat storage capacity among stone fire-proof materials. Here, the calculated data of the pine wall is given for comparison. Thus, for the conditions of the North, arbolite may well replace traditional wall structures made of expensive solid wood (round timber, logs, beams and other products), the main disadvantage of which is a high fire hazard.
The concept of arbolite in Russian combines two Latin words «arbor» -wood and «litos» -stone, in Europe and Latin America it is more commonly referred to as wood concrete -DURISOL. Arbolite is based on wood chips and fibres of plant origin, which meet the criteria of "green" environmentally friendly construction [11][12][13][14]. Lightweight concretes based on porous mineral aggregates are environmentally friendly and non-combustible materials [15].

Principles of design and construction of adaptive housing in the context of Yakutia
In the rural areas of Yakutia, individual dwellings on private plots are mostly built of wooden timber, round timber or lapel logs. The houses are heated with wood stoves or autonomous gas-fired boilers, 85% of which are without basic amenities. In recent years, thanks to a regional government programme, private homes have been connected to central heating from a district or central boiler. In 2022, 45% of private homes in rural areas are connected to central heating. This has made life in rural areas a lot easier, but it has revealed another problem. The farm-built wooden houses are woefully inadequate in terms of energy saving and energy efficiency. With the increase in heat tariffs, this problem is getting worse every year. Thus, in today's conditions in Yakutia, there is a demand for the construction of the most habitable, affordable construction, energy-efficient and adaptive to climate change dwellings. Such a project is also relevant for city dwellers living in huge cottages, where there is a question of reducing the thermal circuit of the house against the background of a rapid rise in the cost of thermal energy.
The above-mentioned modern problems of living in northern conditions prompted the authors to undertake the development of an adaptive energy-efficient residential building, the main criteria for the design and construction of which are: 1) cost-effective construction; 2) minimum heat loss during exploitation; 3) maximum use of available and local materials; 4) adaptability to climate change.
In adopting the optimum volume-planning solution for a dwelling house, the principles of the traditional way of living (survival) of the Sakha (Yakut) people in the extreme climatic conditions of Yakutia were used. Winter dwellings (kystyk) are based on the principle of energy conservation, while summer and transitional dwellings (sayylyk and otor) are based on the principle of closeness to nature. The adaptive energy-efficient residential building is divided into three functional areas, one of which is the living area. The living area is protected from cold winds on three sides of the world: north, west and east. To the north, where the coldest winds prevail, there is a utility area with a garage and a sauna. On the west and east are the summer veranda areas, respectively. In the room of the summer zone, when the ambient air gets warmer, a woodburning cooker can be kindled, creating a micro-climate and expanding the living space.
Permanently heated building circuits: -residential area, with an optimum temperature of 20-22°C and relative humidity 30-45% (GOST 30494-2011 "Residential and public buildings. Microclimate parameters in the premises"); -a technical area with a garage where the temperature is kept at a constant level not exceeding 5°С (SNiP 21-02-99 "Parking lots"), which can be raised to a comfortable temperature for work or other activities if necessary.
By creating a second room circuit around the living area, heat can be retained as much as possible during the heating period and simultaneously kept cooler during the hot summer. This means that only the living area is heated at the optimum temperature for living and the technical area, where the temperature is kept no higher than 5°С. By reducing the temperature to 5°С maximum heat savings are achieved during the heating season.
The ground floor of the living area (Fig. 1) has a large space with an entrance hall, living room, dining room and kitchen area. There is one bedroom with an area of 8 m2. Combined bathroom in the centre of the building, with no "cold" walls, and stairs leading to the upper level. Modern adaptive living is a direct response to changing lifestyles, environmental challenges, cultural and economic factors. In the recent global crisis caused by the coronavirus pandemic, our homes played a key role. Living spaces, forced to act as offices, schools, gyms and even restaurants, have undergone a major reassessment. Both the concept of housing and its furnishings have been comprehensively rethought. The boundaries between rooms in the modern home are becoming increasingly blurred, the division into zones is becoming more and more arbitrary. To create a flexible, multifunctional environment in small spaces, the authors are convinced that the smaller the home, the more adaptable and mobile it should be. The kitchen, in turn, is being integrated more and more tightly into the adjacent living space: it is no longer a place for preparing food, but a communication centre, a meeting place for family and friends. The concept sees the kitchen as an extension of the living room. The zones are aesthetically linked, flowing seamlessly into one another.
In the utility area there is a garage, a bathhouse and technical equipment for the maintenance of the house. The connection between the dwelling and the utility area is made through a fire door. Summer quarters are a veranda and an additional room where a warm climate (spring, summer, autumn) may create a microclimate and expand the living space with a wood-burning cooker. This space can be used regardless of the weather conditions. Regardless of the season, winter or summer, the functionality of a glazed veranda is priceless. During the harshest of frosts, it will protect the entrance door from the wind and reduce the temperature difference between the inside of the house and the environment. This will have a beneficial effect on heating energy savings, which is one of homeowners' highest expenses. In summer, a glazed veranda can be used as a hallway that will provide the family with shade and coolness on a hot day.
On the second level of the living block ( Fig. 2) are the children's bedrooms, where the optimum temperature is always maintained. The second level has access to a summer terrace on the roof of the technical block, where in the hot summer (sharply continental climate) it is possible to take shelter in the shade or be in the sun (Figure 3). The occupants of the adaptive dwelling house can arrange an open space on the terrace at their discretion -organise an area for work, leisure, or sports. The functionality of such spaces is limited only by the owners' imagination. Sun loungers, cosy sofas with plaids and a barbecue area can be built on the terrace. A play area for children, a gym or a summer office can also be arranged depending on family size and preferences. Owners can use the terrace for cosy evenings with the family or for parties. The terrace is, however, an open space which is only used mostly during the warm season The foundation for the house is a 0.9 m thick base of rock rubble, reinforced with a geogrid every 0.3 m. To prevent heat transfer into the permafrost, a layer of extruded polystyrene foam insulation is placed between the monolithic slab and the gravel bed.
Materials and constructions: -Foundation -ribbed (ribs upwards) monolithic reinforced concrete slab -the filler of crushed stone of coarse fraction of rock -The walls of the technical block are shallow concrete block, the living quarters and summer quarters are MHM wood panels; -Insulation -mineral wool slabs of different densities; -Floor slabs -to prevent condensation, all slabs are made of sandwich panels (double profiled sheets with dense mineral fibre insulation).
The result is an adaptive, energy-efficient house that makes it easier to live in the Arctic, but is also energy-efficient (Fig. 4). The most critical point in northern construction is the choice of foundation type. In the design of foundations and foundations of buildings and structures, according to the building regulations 2 principles can be used. According to principle I the ground soil is used in the frozen state, which must be preserved during construction and for the entire period of operation of the building or structure. In our opinion, for individual low-rise construction it would be preferable to choose a foundation according to Principle II, where permafrost soils are used in the thawed state with the assumption of their thawing to the design depth. In this case the "heat" of permafrost (on the order of -4 ÷ -10°C) can be used as a heat accumulator for the ground floor. This is paradoxical, but the approach becomes clear if we imagine that the house stands on piles suspended at some height from the ground. And the temperature under the house on the coldest days for Yakutsk is -45 ÷ -64°C. Thus, we have justified the principle of using permafrost as a heat accumulator for individual houses, the foundations of which are built on the ground. In this case, the well-known heat-insulated reinforced concrete foundations (strip, plate foundations) such as the ISS -insulated Swedish slab [16] or earthquake-proof columnar foundations with widened footings can be used [17].

Conclusion
As the experience of construction in Yakutia shows, high-rise construction is carried out en masse only in Yakutsk, the republic's capital, while in other cities it is done on a point-bypoint basis. In rural areas, the bulk of housing is commissioned mainly by private developers. In these circumstances, the creation and implementation of an adaptive individual house project is an urgent issue. Such projects should be tested in the conditions of Central Yakutia, and then replicated for the northern and arctic areas. The main obstacle in the mass construction of adaptive houses is the lack or insufficiency of the necessary materials and structures.
In our view, the positive experience of construction in the development of the Arctic regions during Soviet times should not be ignored. In the Arctic cities of Russia, stone construction was deployed with maximum use of local raw material resources, practically only metal, glass, and cement were brought in. In the countryside, panel houses were built from timber-frame panels delivered from the Leningrad region along the Northern Sea Route all the way to the shores of Chukotka.
It should be noted that adaptive house designs should be developed taking into account the conditions of the area of construction and logistics, as well as modern requirements for resource and energy efficiency, environmental and fire safety.