architecture and construction /5. Heat and gas supply and ventilation

Naumova A.A.

postgraduate student of engineering INRTU, Russia

Exergy analysis of natural ventilation of residential buildings

Nowadays, more and more attention is paid to creating a comfortable microclimate in residential buildings. Factors such as the severity of the climate of our country, a higher degree of heat insulation and sealing of buildings, high energy to maintain microclimate parameters, is of great scientific interest in terms of evaluating the performance of climate control systems. Properly organized recycling heat in the ventilation systems of buildings can significantly reduce the need for energy in buildings. Evaluating the effectiveness of the full utilization of heat (direct and indirect) in the ventilation systems of the building with the exergy flow, ie with the assessment of quality of applied energy, it gives the opportunity to evaluate its work and to identify ways and means of improving the system being analyzed.

Study of ventilation systems exergy method allows to determine the maximum useful work that can make a thermodynamic system in the transition to a state of equilibrium with the environment, consisting of teplootdatchika, working the body, and make circular process of the heat (the environment).

In order to obtain maximum performance in a variety of systems, it is necessary that the process has been reversed - an idealized process. All the real processes are irreversible, therefore extra energy will be transferred to the environment where the energy does not have the ability to convert it into work. Reducing the system's ability to do work is called exergy loss. Until all the system parameters are equal to those of the environment, the equilibrium is reached and the system can produce a certain work, t. E. Have exergy. In irreversible processes the energy is dissipated, exergy, on the contrary, completely disappears when it reaches a state of equilibrium with the environment [1, 2].

Currently, the main analysis tool is the energy balance, which is now the target of all kinds of energy, reflecting the degree of perfection of the process. When the energy balance, which is more properly called a heat, everyone involved in the process of transferring the energies corresponding equivalent in the heat and then balanced, ie It did not take into account the quality of their difference. Energy balance, makes it impossible to determine the location and cause of the energy loss of the right to produce quantitative and qualitative evaluation to find ways to address them.

Exergic method of thermodynamic analysis - a method to take into account the diverse flows Exergy, to assess their performance in the transition to environmental parameters. The main objective of exergy analysis systems is complex optimization settings to maximize the energetic efficiency.

In residential buildings, to maintain a stable internal air temperature during the heating period and maintenance of the system of natural ventilation, due to the pressure difference inside and outside the building, have a heat gain significant weight. For the implementation of the system of natural ventilation is wasted energy, filed into the building heating and heat from people staying in the building. Important need to consider these options, as for determining the minimum required amount of energy / exergy, their share in the heat balance of the building is of great importance.

To create an idealized natural ventilation system is necessary to carry out the allocation of energy costs to transport air from the minimum required heat input in residential building, due to the loss of exergy evaluation of each process in the value of total exergy. [3]

Research exergy method provides information on the possible improvement of the thermodynamic processes that can substantially reduce the need for energy in buildings. For a complete evaluation of the rationality of such improvements is necessary to analyze the various optimization methods (economic, exergy, environmental, etc.), allowing a total show objective vision of the distribution of energy in the building and its technical systems.

Literature

1. Brodyansky, VM, Fratsher, V. Michalek, K. Exergic method and its applications / ed. VM Brodyansky. - M .: Energoatomizdat, 1988.-288s.

2. Shargut J., R. Exergy loops. - M .: Energia, 1968.-280 p.

3. Exergetic calculations technical systems: Right, Manual / VM Brodyansky, GP Verhivker, Ya Ya Karchev etc .: Ed. Dolinskogo AA, VM Brodyansky Ukrainian Academy of Sciences. Institute of Engineering Thermophysics. Kiev: Nauk.dumka, 1991.-360 with.