The decision of problems of reliability of work of networks of a heat supply in conditions of instability of consumption of hot water

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Vladimir state University named after A. G. and N. G. Stoletovs

The decision of problems of reliability of work of networks of a heat supply in conditions of instability of consumption of hot water

Belov R.A.

Vladimir, Russia

Improving the reliability of heat supply systems, timely and comprehensive preparation for the heating period and holding it in interaction of heat supply organizations and consumers of thermal energy, fuel, water and other organizations are essential measures to ensure continuous heat supply in cities and other human settlements.

Reliability of heat supply systems - is the ability to produce, transport and distribute among the consumers in the required quantities of the heat carrier compliance with specified parameters under normal operating conditions. The notion of reliability of heat supply systems based on probabilistic evaluation of the system, which in turn is associated with a probabilistic rating will continue, of its elements, which is determined by the law of distribution of time of this work^[3].

The reliability of the heat supply system is a complex property and may include separately or in combination a number of properties, the main of which are:

• reliability - the property of heat supply system to remain operational continuously for a specified time or specified developments;

• durability - the property of the equipment and heat networks to remain operational until the occurrence of a limit state when the installed system maintenance and repair;

• maintainability - the property of an object, which consists in adapting to the prevention and detection of the causes of its failure, damage and mitigation by conducting maintenance and repair;

• modal controllability - is a property of object to maintain the normal mode through the control;

• persistence - the property of heat supply system to withstand perturbations, without their cascade development with mass violation of the consumers.

The solutions to the problems of reliability of work of networks of a heat supply in conditions of instability of consumption of hot water:

1. The installation of the circulating valve

Hot water system in the vast majority of cases have a variable hydraulic regime. Hydraulically to balance such systems is possible only with automatic valves. heating steam communal pipeline

When the temperature of the water in the circulation pipe above the target on the valve, it is covered, limiting circulation to a minimum, corresponding to heat loss in the pipes. If the water temperature falls below a predetermined value, the valve opens and increases its circulation. Thus the whole system is in equilibrium, temperature and hydraulic regime.to cope with their task - a thermal management system, which is a consequence of the hydraulic regulation.

The presence of jumpers allows you to provide uninterrupted heating and greatly reduce the heat lost in an accident. The number and diameters of the jumper settings are determined based on the redundancy mode with reduced coolant flow.

2. The device jumpers between trunk networks

The reliability of the heat supply system can be improved by the device of the crosspieces between the main networks that are laid radially from one or different sources of warmth.

The specifics of the domestic hot water systems until recently, unlike in the

West, was the necessity of grouping hydrant risers kolowski the cross sectional nodes and join each sectional host one circulation pipe for circulating the prefabricated pipeline system. In section nodes pooled from three to seven stand-pipes.

For such design decisions appropriate controls on the circulation areas located between the attachment points of the last stand of the instruments on the risers and Colusa jumper. Then the thermostat will fully cope with their tasks - control system, which is a consequence of the hydraulic regulation.

The presence of jumpers allows you to provide uninterrupted heating and greatly reduce the heat lost in an accident. The number and diameters of the jumper settings are determined based on the redundancy mode with reduced coolant flow.

3. Installation of pressure regulators

Features high-rise buildings is the uneven water pressure from consumers on different floors, caused by the action of gravitational pressure which should not exceed 0.6 MPa or 0.45 MPa, as well as uneven pressure caused by the increase in the number of consumers. Eliminate these drawbacks by use of a pressure regulator after itself, RP 226 directly to consumers.

In this system each consumer is equal to the hydraulic conditions and are not allowed devastating impact of excess pressure on the taps etc. in addition, this controller eliminates the dissatisfaction of consumers of the need for constant temperature control water mixer, for example, in the shower, because of the uneven distribution in the system of hot and cold water.

4. Use in heat networks pumps to create pre-set pressure and supply of the required amount of water to the consumers

Network pumps create water circulation in the heating system, and makeup to compensate for leakage and maintain the required level piezometric lines with static and dynamic modes. The number of network pumps is not less than two, of which one is standby. If the network operation under design conditions required the installation of four pumps, the backup pump is not provided. In closed systems of heat supply shall be at least two makeup pumps, and open - at least three, one of whom is a reserve.

5. Installation of storage tank

The availability of storage reservoirs allows to align the uneven consumption of hot water and decrease the surface of the heaters based on the conditions of the calculation the performance of water heaters at the average hourly consumption of heat for hot water.

At the location of the tanks distinguish between upper and lower, by design, open and closed. In closed tanks is stored the pressure of the water, and in the open he is completely lost. But an open tank more secure, because it is not a pressure vessel. In addition, the mode of operation distinguish tanks: with variable temperature and constant volume, respectively, with constant temperature and variable volume. The capacity of the storage tank are determined on the basis of the integrated graphics supply and consumption of heat in the system GSV.

References

1. MDS 41-6.2000 - The organizational-methodological Recommendations on the preparation for the heating period and to improve the reliability of systems of a communal heat supply in cities and settlements of the Russian Federation. - M.: SPO ORGRES, 2000. - 37 p.

2. RD-03-94 - Rules of arrangement and safe operation pipelines of steam and hot water.

3. SP 124. 13330.2012. The thermal network. The updated edition of SNiP 41-02-2003.

4. Pyrkov V.V. Modern heating units. Automation and control - K. II DP "Tack right", 2007. - 252.

5. Proc. for high schools/A.A. Kalmakov, J.I - Kuvshinov, S.S. Romanov, S. Shchelkunov, A.; Under the editorship of V.N. Theological. - M.: Stroiizdat, 1986. - 479 p.: 11.

6. https://www.derev-grad.ru/gradostroitelstvo-i-arhitektura/sistemyinzhenernyh-sooruzhenii-i-kommunikacii/otoplenie-ventilyaciya-ikondicionirovanie-vozduha/ukazaniya-po-povysheniyu-nadezhnosti-sistem-k.pdf

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