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Creation of individual heat points in a centralized heat exchange system
T.O. Codirov student of
Tashkent State Technical University
Abstract : This article presents the implementation of centralized heat transfer systems by switching to modern, energy-efficient individual heat transfer systems.
Keywords: thermal power station, central heating unit, temperature, main pipelines, outdoor air, individual heating unit, connection module, heating, water supply, circulation, heat exchanger.
Today, the heat distribution system in urban areas is almost everywhere centralized, i.e. Heat is transferred by main pipelines from the CHPP and district boiler houses to the central heating centers (CHP), from where it reaches individual houses through the distribution network.
Qualitative regulation of the temperature of the coolant, depending on the temperature of the outside air, is most often carried out centrally from heat sources. But in order to ensure the required temperature of hot water at the outlet of the central heating station at 55-60 º C, the temperature of the water in the supply pipe cannot be reduced below the temperature of the “break point” of the temperature graph - about 70 º C.
Thermal accounting (if any) is maintained in the central heating center, i.e. for a whole block of houses. At home, heat consumption is distributed according to their share of the total heated area.
In houses, the parameters of water from the heating network (most often 150/70 º C with a cut-off of 130 º C) are reduced to 95/70 º C - standard design parameters in the heating systems of houses. With a dependent connection scheme, this is done using mixing stationary elevators. Uniform distribution of network water over connected houses is achieved by installing specially designed throttle washers at the inlets, which require a stable flow (pressure) in heating networks.
The disadvantages of the existing centralized heat distribution system are:
the four-pipe distribution network scheme is material-intensive, expensive during construction, and attacks during operation; has large heat losses, which are included in the calculation with consumers (the meter on the central heating center measures all the heat consumed "after itself", that is, including heat losses in distribution networks, and there is no way to compare them with the normative); in connection with calcium deposits and corrosion, more frequent replacement of pipes for hot water supply and recycling is required ; in general, stainless steel pipes should be used for hot water pipelines;
switching the central heating system to quality regulation (in order to abandon local unregulated elevators) will require shifting heating pipelines to increase their diameter and throughput, as a graph of 95/70 º C (∆ t = 25 K) suggests larger pipe diameters than the temperature difference of 150/70 º C (∆ t = 80 K);
heat metering is not performed at the place of provision of services at the entrance to the heated building, does not correspond to the actual heat consumption and is not fair (due to the uneven consumption of heat by dissimilar consumers in terms of number of storeys, degree of thermal protection, direction of wind and light exposure, etc.);
distribution heating networks are disconnected for maintenance;
installation of throttle washers is very time-consuming, and must be redone with every change in the hydraulic situation in the network - with any connections or disconnections of consumers, i.e. practically does not lead to the desired result for many reasons;
a centralized heat distribution scheme leaves a maximum of fixed assets in the heat distribution agency (central heating and four-pipe distribution network); Thus, the operation, repair and maintenance of these funds must be carried out by them, which will require enormous funds, which are equally needed for the reconstruction of thermal power plants, boiler rooms and heating networks.
ITP is the most important component of building heat supply. The regulation of heating and hot water, as well as the efficiency of the use of thermal energy, largely depend on its characteristics. Therefore ITP received much attention during the term odernizatsy buildings and on large-scale projects currently in their arrangement in apartment buildings come to life in various regions of Uzbekistan e .
In connection with the mass installation of ITP, the distribution of thermal energy from the heat source to the consumer also changes (Fig. 1).
Image connection individual heating units of houses, central heating, ITP.
Modern solutions allow you to connect each building directly to a heat source, bypassing the central heating points (DHC).
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