A. P. Butova, assistant professor
Mikhaylo Tugan-Baranovskyy
Donetsk National University
of Economics and Trade
M. Pavlyuk
HOUSING DEVELOPMENT
OPTIMIZATION TAKING INTO ACCOUNT HEAT LOSSES DUE TO AIR INFILTRATION AND
EXFILTRATION THROUGH THE BUILDING ENVELOPE
Energy saving is
one of the key priorities of the economic development both in Ukraine and many
other European countries. Energy saving in
all the spheres of economic activity is becoming one of the main objectives as
the energy expenses make up a considerable part of the cost of any product, goods or services.
About a quarter
of all the fuel burnt in our country is used to supply heat to residential
houses and civil offices. Even if there is a considerable reduction in energy
consumption in the industry, agriculture, building and transportation branches,
the consumption volume in the social sector is stable in its nature and is
viewed as a certain constant parameter.
The
implementation of modern architectural technologies in the process of solving
energy saving problems can considerably improve the heat protection of the
buildings and result in important economic advantages. The level of heat
protection of the buildings is 1.5 - 1.8 and 2.0-2.5 times higher in European
and Scandinavian countries respectively if compared to Ukraine. [1] Therefore,
architectural and construction methods of energy saving needs studying,
Developing and efficient implementation. Relevance of their use is also determined by the fact
that such methods are environmentally friendly as well as the increase in the
reconstruction volume aimed specifically at the thermorenovation of existing
buildings and the volume of
construction in general. Moreover,
creation of comfortable conditions by means of architectural and construction
energy saving methods can have far more stable results.
According to the
Law of Ukraine "On energy saving" in order to carry out
efficient and meaningful activities of the state aimed at organization and
coordination of the measures in the sphere of energy saving, state,
regional
and local purpose-oriented programs
are elaborated and adopted. Scientific research on energy saving results in more
or less modern methods of ventilation heat losses calculation and heat losses
minimization for buildings as well as the formation of the optimal air and heat
mode [2].
However a considerable part of energy
which is used to create appropriate sanitary and hygiene conditions and
microclimate in buildings is lost due to infiltration of air through building
envelopes, faulty joints and connections, ventilating stacks, heat bridges, etc. [3].
According to the
calculations of German engineers and designers [4] 4% of heat energy are lost in a hot water supply system, 11 % - in heating devices, 3% - through the roof, 7% - through windows, 6% - through doors, 11% are absorbed by heat bridges, 17% are lost in ventilating
stacks. Thus, total heat losses in the systems of hot water
supply and heating make up 15%, losses due to construction peculiarities – 16%
and losses due to the uncontrolled ventilation of buildings – 28%.
In the regions of
Ukraine with cold or moderate climate the heat losses due to infiltration and
exfiltration of the air through the building envelope also make up a
considerable part of the total heat losses especially for building built in the
50ies-70ies of the previous century, which in general are less wind resistant
than modern buildings.
Air mode of a
building is a total of factors and phenomena which determine the general
process of exchange with all its rooms and external air, including the air inside the building, air filtration through the building envelope, openings,
air
passages and airflow [3].
Air mode is
connected to the heat node of the building. Infiltration of external air results in additional
energy expenditure for inside heating. Exfiltration of the inner
humid air reduces the heat protection
properties of the building envelope.
The issue of heat
protection properties of a building can be viewed in several key approaches to
saving the heating energy in buildings, although the most crucial one is the optimization of architectural and
structural solutions for building
envelopes.
Thus, our main objective is to elaborate the method of
optimization of construction solutions for external building envelope of civil
offices taking into consideration the heat losses resulting from air
infiltration and exfiltration.
Optimization of
the architectural and structural solutions for building envelopes means the
creation of such building envelopes which can provide the lowest possible
energy consumption level for the building with all functional requirements
being met and at the minimum possible cost at the same time.
In order to reach
this objective it is necessary:
- to classify the building in terms of the type and material used for the building envelope;
- to carry out an extensive experimental scientific research of the wind pressure on the building;
- to carry out an experimental research with the use of a hydrodynamic tunnel in order to determine airflow aerodynamic spectrum of the buildings, velocity field of the backwash;
- to continue developing a mathematical model of the evaluation of the wind pressure on the building surfaces;
- to elaborate the evaluation methods for the wind pressure of the buildings in order to define the heat losses resulting from air infiltration and exfiltration through the building envelope;
- To implement the results of the research in the engineering, design, building and reconstruction techniques for the civil buildings as well as reflecting them in the official regulatory documents.
As a result of the given objective being reached the optimal heat engineering solutions must be chosen in the sphere of heat protection and maintaining heat comfort of the buildings which would guarantee minimum annual heating expenses.
In order to calculate energy saving computer mathematical model of the building will be used which will help to define the parameters of heat losses and seasonal energy consumption. Certain suggested measures will be tested on the model and the complex of measures will be considered in order to find the most efficient variant.