The concept model of sustainable buildings refurbishment/koncepcinis darnaus visuomeniniu pastatu atnaujinimo modelis.(Report)

There are much more factors influencing refurbishment sustainability than was mentioned here. The concept of sustainable refurbishment should cover and integrate all the possible economic, social and environmental needs. It makes sustainable refurbishment very sophisticated. Therefore, recent papers adopt decisions on economically efficient refurbishment to new technology methods: Adeli (1998) applies general theories and techniques of expert systems to construction, Henket (1990) suggests a theoretical model of several modular stages in the decision process, Reddy et al. (1993) offer a frame-based decision support model for building refurbishment, Rosenfiels and Shohet (1999), Lavy and Shohet (2007)--decision support model for semi-automated selection of renovation alternatives, Alanne (2004) proposes a multi-criteria "knapsack" model to help designers select the most feasible refurbishment actions in the conceptual phase of a refurbishment project, Dascalaki and Balaras (2004)--new XENIOS methodology for assessing refurbishment scenarios and the potential of application of renewable energy sources and rational use of energy in the hotel sector. Kaklauskas and Gulbinas (2005), Kaklauskas et al. (2005, 2006), Zavadskas and Kaklauskas (2000), Zavadskas et al. (1997, 2001a, 2004, 2008), Antucheviciene et al. (2006), Saparauskas and Turskis (2006), Banaitiene et al. (2008) integrate various IT supported knowledge management, decision support, expert models for buildings' life cycle management as well as refurbishment projects' assessment and optimization.

Recently more attention is paid on negative pollution effects decreasing measures. Kaklauskas and Zavadskas (2007) presented decision support system for innovation with special emphasis on pollution, Zavadskas et al. (2007a)--research on modelling and forecasting of a rational and sustainable development of Vilnius with emphasis on pollution, Zavadskas et al. (2007b) performed Vilnius urban sustainability assessment with an emphasis on pollution.

Numerous sustainable buildings refurbishment models are proposed in the literature. Among the most typical approaches there are development models for energy efficient renovation, which through the use of new materials and the testing of new techniques also support different branches of the construction industry. Siller et al. (2007) presents the model describing the temporal development of the Swiss building stock and its energy demand due to heating and hot water generation. The building stock is characterized by the energy reference area (ERA), which is a measure for the effective heated area. In the renovation sub-model every building (represented by the corresponding ERA) is subject to a sequence of renovations, which are determined by the renovation period and the fraction of realized renovations [f.sub.r].

Sitar et al. (2006) considered the model of sustainable renovation of a multi-apartment building. The sustainable renovation of a building is presented in two scenarios, in which an energy efficient renovation examines the connection between possibilities of architectural design, renovation technology, and energy efficiency for the heating of the building.

Van der Flier and Thomsen (2005) presented analytical model which starts from the definition of renovation as "transformation (process) of the physical, functional, financial, architectural and ecological characteristics of a building or project (product) to realize a comprehensive and useful extension of the lifespan". It takes two steps: the first one is a description of the initial situation and the objectives of the participants and a description of the renovation process and product. Second step is an assessment of the results by means of the evaluation criteria effectiveness of the process (goal attainment), efficiency of the product (cost-benefit relation) and legitimacy of both process and product (support and acceptance from participants).

Caccavelli and Gugerli (2002) presented refurbishment decision making model for office buildings refurbishment under TOBUS project. Model includes building type, various data analysis, refurbishment and modernization alternatives selection, decision making process, actions plan and refurbishment strategy development, implementation phases.

European Commission (2003) initiated FP-5 Sustainable refurbishment project SUREURO. SUREURO has developed models and systems that provide housing organisations, interested parties; local authorities, town planners, construction companies etc, opportunities to perform refurbishment processes within a normal time schedule and budget. The SUREURO models and systems offer users considerable environmental improvement and energy savings. The effort of SUREURO is to combine an overview of usable and available SUREURO models and systems and the context on which housing people can use these tools and, furthermore, what kind of management and participation skills are required in order to be successful. In proposed sustainable refurbishment model Sustainable Process Management connects the key topics Property and Facility Management, Strategic Management and Cooperation and Participation Management and follows principles of sustainable development: social, cultural, environmental and economic.

Other sustainable refurbishment models are based on Building Life Cycle Analysis and costs management. For example, project SAVE "Refurbishment of Buildings at High Quality and with controlled costs" (2005) considers an integrated planning of the refurbishment-process, on the other hand, enables an economic optimisation in terms of the whole lifecycle-costs (LCC) of the building. Integrated planning is defined as a concept with LCC assessment as the core element, which is; however, open for additional quality related criteria depending on the preference and the framework conditions of the investor.

It can be summarized that sustainable refurbishment is significant problem in current buildings stock taking much scientists attention as well as European Commission initiatives. Sustainable refurbishment is widely discussed in the literature and various models and decision making tools proposed. Indeed in this article conceptual sustainable refurbishment model presented by authors synthesizes various sustainable refurbishment elements and new refurbishment aspects to be considered in sustainable refurbishment development.

3. THE CONCEPTUAL MODEL OF SUSTAINABLE BUILDINGS REFURBISHMENT

The main results expected from public buildings refurbishment are:

* Energy savings;

* Increase of comfort;

* Healthy working environment assurance;

* Extension of building life cycle;

* Economized exploitation;

* Environmental protection.

Basing on aforementioned expected results and the general sustainable refurbishment principles authors propose sustainable refurbishment model where main factors influencing models efficiency--macro and micro environment, buildings refurbishment decisions making groups--are additionally considered. Model also involves decision making process and sustainable refurbishment information dissemination in all decision making stages (see Figure 1).

Elements of proposed model are further discussed.

Sustainable refurbishment principles. Sustainable refurbishment must reconcile further dimensions:

* social (collaboration, public awareness and education, social safety, etc.);

* ecological (ecological construction materials, energy, waste, noise, land use, heath, air quality, etc.);

[FIGURE 1 OMITTED]

* economic (cost-efficient price, fair price and good service, energy saving reliability, etc.);

* cultural (cultural heritage, behavioural norms, etc.);

* architectural (comfort, aesthetics, decoration, environment, buildings purposes matching exterior, etc.);

* technical (innovative HVAC technologies, energy saving technologies, etc.).

All the above mentioned dimensions are closely related, complementing each other and influence general refurbishment efficiency. Sustainability dimensions are inseparably connected, i.e. usage of innovative technologies in building refurbishment can satisfy ecological and economic needs, or cultural and architectural dimensions encourage social needs satisfaction.

Sustainable building refurbishment should be implemented basing on the aforementioned principles.

Citizen's healthcare principle. Safe buildings environment must be ensured. It means taking care about air quality in premises, lightening, control of noise levels and water pollution by chemical substances, etc. Good air quality in premises can noticeably improve living quality, especially for people with allergic diseases. In order to ensure healthy living and working conditions it is necessary to take care both of indoor microclimate and external environment. General parameters determining indoor microclimate to be controlled before and after refurbishment are: air velocity, humidity, dew point, lightening, air circulation velocity, acoustics, and temperature. In order to ensure healthy external environment, substances quantity in the air must be controlled: sulphur dioxide, nitrogen dioxide, particular matters, ozone. Exceeding norms substances quantities in the air can encourage some kinds of illnesses.

Effective energy use principle. Particularly energy consumption encourages environmental problems i.e. global warming, acid rain. In order to ensure energy efficiency in buildings modernization and refurbishment main attention must be paid on buildings insulation, heating, cooling, conditioning, lightening systems design. The best results usually achieved when modern innovative energy saving measures in buildings refurbishment applied: buildings insulation by innovative materials (e.g. Erhorn-Kluttig and Erhorn, 2007), energy efficient windows (e.g. Engelund, 2007; James and Bahaj, 2005), hybrid ventilation (e.g. Jicha and Charvat, 2007), natural lightening (e.g. Athanassakos, 2007), buildings heating and conditioning by solar energy, solar headers, solar batteries (Voss, 2000; Ferrari and Adhikari, 2007), passive solar energy using buildings heating systems (Buvik and Hestnes, 2007), heating pumps.

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