We complete any heating points with all necessary equipment. Thermal points and heat metering units are, first of all, complex engineering solutions. Of course, the simplest, tested solutions have long been available and often used, but this does not mean that the heating point ceases to be a complex engineering system.

Therefore, within additional equipment almost anything can be used in thermal points:

• Monitoring and control systems for any communication protocols.
• Specialized devices for the individual security of the facility.
• Electronic and computer means of control, diagnostics, control.
• Control valves with individual drives, computer controlled.
• Complex systems for displaying, storing, and transmitting information.
• Uninterruptible power supply systems - UPS, DGU.
• And other equipment.

Basic equipment:

Name: Heat exchange equipment.

Description: The heat exchanger is one of the main components of the heat point. Responsible for the transfer of heat from the external network to the internal coolant.

Definition: Heat exchanger, heat exchanger, a device in which heat is exchanged between two or more heat carriers or between a heat carrier and a surface solid body. The process of transferring heat from one coolant to another is one of the most important and frequently used processes in technology.

Name: Pumps and pumping equipment

Description: pumps in heating point perform their direct task - they are responsible for the movement of coolants, according to sometimes complex schemes, with the help of which heat is transferred from centralized network to the end consumer.

Definition: Pump - a device for the continuous injection, compression or suction of fluids by mechanical or other means.

Distinguish:
- pumps for liquids;
- compressors, fans, blowers, vacuum pumps and other devices for pumping or exhausting gases and vapors

Name: Shut-off and control valves

Description: Fittings (from lat. armatura - weapons, equipment) - a set of auxiliary, usually standard, devices and parts that are not part of the main parts of the machine, structure, structure and ensure their correct operation. Pipe fittings (for water, steam, gas, fuel, various products of processing of the chemical, food, etc. industries), are divided into:

By appointment: shut-off (cocks, gate valves), safety (valves), control (valves, pressure regulators), outlet (air vents, steam traps), emergency (alarm beeps), etc.

According to the method of connection to pipelines: flanged, threaded, welded.
According to the principle of action: rotary, saddle.
According to the limiting parameters of the transported medium(pressure, temperature)
Body material: non-ferrous metals (bronze, brass), cast iron, steel.

Name: Instrumentation and control equipment

Description: Instrumentation and automation: - special kind fittings that differ from the rest, containing counting, measuring, recording, storing, printing and other instrumentation. There are heat meters, water meters, various flow meters, pressure gauges, thermometers, signaling devices, flow and pressure sensors, controllers, control panels and other devices.

Definition: see point 3 for the nominal definition of reinforcement.

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Heating point equipment

At district heating heating point may be local- individual (ITP) for heat-consuming systems of a particular building and group- central (CTP) for systems of a group of buildings. ITP is located in special room buildings, the central heating center is most often a separate one-story building. The design of heat points is carried out in accordance with regulatory rules.

The role of a heat generator with an independent scheme for connecting heat-consuming systems to an external heating network (see Fig. 1.1, b) is performed by a water-to-water heat exchanger (Fig. 1.4).

Currently, so-called high-speed heat exchangers are used. various types. Shell and tube water-to-water heat exchanger(Fig. 1.4, a) consists of standard sections up to 4 m long. Each section is steel pipe up to 300 mm in diameter, inside which several brass tubes are placed. In an independent scheme of a heating or ventilation system, heating water from an external heat pipe is passed through brass tubes, heated water is counter-current into annulus, in the hot water supply system, heated tap water is passed through the pipes, and heating water from the heating network - in the annulus. More advanced and much more compact plate heat exchanger(Fig. 1.4, b) is recruited from a certain number of steel profiled plates. The heating and heated water flows between the plates countercurrently or crosswise. The length and number of sections of a shell-and-tube heat exchanger or the dimensions and number of plates in a plate heat exchanger is determined by a special thermal calculation.

For heating water in hot water systems, especially in an individual residential building, it is more suitable not for high-speed, but DHW tank(Fig. 1.4, c). Its volume is determined based on the estimated number of simultaneously operating water points and the estimated individual characteristics of water consumption in the house.

Common to all circuits shown in Fig. 1.1 is the application pump for artificial stimulation of water movement in heat-consuming systems. In the first two schemes (see Fig. 1.1, a, b), the pump is connected directly to the building systems. In dependent schemes (see Fig. 1.1, c, d), the pump is placed at a thermal station, and it creates the pressure necessary for water circulation, both in external heat pipelines and in local heat-consuming systems.

A pump operating in closed rings of systems filled with water does not lift, but only moves water, creating circulation, and therefore is called circulation. Unlike a circulation pump, a pump in a water supply system moves water, raising it to the points of analysis. In this use, the pump is called upward.

The circulation pump does not participate in the processes of filling and compensating for the loss (leakage) of water in the heating system. Filling takes place under the influence of pressure in the external heat pipelines, in the water supply system or, if this pressure is not enough, using a special make-up pump.

Until recently, the circulation pump was included, as a rule, in the return line of the heating system to increase the service life of parts interacting with hot water. In general, to create water circulation in closed rings, the location of the circulation pump is indifferent. Lower slightly if necessary hydraulic pressure in a heat exchanger or boiler, the pump can also be included in the supply line of the heating system, if its design is designed to move more than hot water. All modern pumps have this property and are most often installed after the heat generator (heat exchanger). Electric power the circulation pump is determined by the amount of water being moved and the pressure developed at the same time.

IN engineering systems ah, as a rule, apply special foundationless circulation pumps, moving a significant amount of water and developing a relatively small pressure. This silent pumps, connected in a single unit with electric motors and fixed directly on the pipes (Fig. 1.5). The system includes two identical pumps (see Fig. 1.5, b), acting alternately: when one of them is operating, the second is in reserve. Shut-off valves(valves or cocks) before and after both pumps (active and inactive) are constantly open, especially if their automatic switching is provided. check valve in the circuit prevents the circulation of water through an inactive pump. Easily installed foundationless pumps are sometimes installed one at a time in systems. At the same time, the reserve pump is stored in a warehouse.

The decrease in water temperature in the dependent circuit with mixing (see Fig. 1.1, c) to the permissible tg occurs when high-temperature water t1 is mixed with reverse (cooled to a temperature tо) water local system. The coolant temperature is lowered by mixing return water from engineering systems using a mixing apparatus - a pump or a water jet elevator (Fig. 1.6). pump house mixing plant has an advantage over the elevator. Its efficiency is higher, in case of emergency damage to external heat pipelines, it is possible, as with an independent connection scheme, to maintain water circulation in the systems. The mixing pump can be used in systems with significant hydraulic resistance, while when using an elevator, pressure losses in the heat-consuming system should be relatively small. Water jet elevators received wide use thanks to its smooth and quiet operation.

The internal space of all elements of heat-consuming systems (pipes, heaters, fittings, equipment, etc.) is filled with water. The volume of water during the operation of the systems undergoes changes: when the water temperature rises, it increases, and when the temperature drops, it decreases. Accordingly, the internal hydrostatic pressure changes. These changes should not affect the performance of the systems and, above all, should not lead to exceeding the ultimate strength of any of their elements. Therefore, the system is introduced additional element - expansion tank(Fig. 1.7).

The expansion tank can be open, communicating with the atmosphere, and closed, under the variable, but strictly limited overpressure. The main purpose of the expansion tank is to receive the increase in the volume of water in the system, which is formed when it is heated. At the same time, a certain hydraulic pressure is maintained in the system. In addition, the tank is designed to replenish the loss of water in the system with a small leak and when its temperature drops, to signal the water level in the system and control the operation of make-up devices. Through an open tank, water is removed into the drain when the system overflows. In some cases, an open tank can serve as an air vent from the system.

An open expansion tank is placed above the top point of the system (at a distance of at least 1 m) in attic or in the stairwell and covered with thermal insulation. Sometimes (for example, in the absence of an attic), an uninsulated tank is installed in a special insulated box (booth) on the roof of the building.

The modern design of a closed expansion tank is a steel cylindrical vessel, divided into two parts by a rubber membrane. One part is designed for system water, the second is factory filled with an inert gas (usually nitrogen) under pressure. The tank can be installed directly on the floor of a boiler room or heating point, as well as fixed on the wall (for example, in cramped conditions in the room).

In large heat-consuming systems of a group of buildings expansion tanks are not installed, and the hydraulic pressure is regulated by permanently operating booster pumps. These pumps also compensate for water losses that normally occur through leaky pipe connections, fittings, appliances, and other system locations.

In addition to the equipment discussed above, the boiler house or heating point houses automatic control devices, shut-off and control valves and instrumentation, which ensure the current operation of the heat supply system. The fittings used in this case, as well as the material and methods for laying heat pipes, are discussed in the "Heating of buildings" section.

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KSB

Pipe fitting program KSB 2015

Thermal point(TP) is a complex of devices located in a separate room, consisting of elements of thermal power plants that ensure the connection of these plants to the heating network, their performance, control of heat consumption modes, transformation, regulation of parameters coolant and distribution of the coolant by types of consumption.

Substation and attached building

Purpose

The main tasks of the TP are:

• Converting the type of coolant
• Control and regulation of coolant parameters
• Distribution of heat carrier by heat consumption systems
• Shutdown of heat consumption systems
• Protection of heat consumption systems from an emergency increase in the parameters of the coolant
• Accounting for coolant and heat consumption

Types of heat points

TPs differ in the number and type of heat consumption systems connected to them, individual characteristics which, determine thermal scheme and characteristics of the TP equipment, as well as by the type of installation and features of the equipment placement in the TP room. There are the following types of TP:

• Individual heating point(ETC). It is used to serve one consumer (building or part of it). Usually located in the basement or technical room building, however, due to the characteristics of the serviced building, it can be placed in a separate building.
• Central heating point(CTP). Used to serve a group of consumers (buildings, industrial facilities). Most often located in a separate building, but can be placed in the basement or technical room of one of the buildings.
• Block heat point(BTP). It is manufactured in the factory and supplied for installation in the form of ready-made blocks. It may consist of one or more blocks. The equipment of the blocks is mounted very compactly, as a rule, on one frame. Usually used when you need to save space, in cramped conditions. By the nature and number of connected consumers, the BTP can refer to both ITP and CHP.

Heat sources and thermal energy transport systems

The source of heat for TP are heat generating enterprises ( boiler rooms , combined heat and power plants). TP is connected to sources and consumers of heat through heating networks. Thermal networks are divided into primary main heating networks connecting TP with heat generating enterprises, and secondary(distributing) heating networks connecting TP with end consumers. The section of the heating network that directly connects the heating substation and the main heating networks is called thermal input.

Trunk heating network, as a rule, have a large length (distance from the heat source up to 10 km or more). For the construction of trunk networks use steel pipelines diameter up to 1400 mm. In conditions where there are several heat generating enterprises, loopbacks are made on the main heat pipelines, uniting them into one network. This allows you to increase the reliability of the supply of heat points, and, ultimately, consumers with heat. For example, in cities, in the event of an accident on a highway or a local boiler house, heat supply can be taken over by the boiler house of a neighboring district. Also, in some cases, the common network makes it possible to distribute the load between heat generating enterprises. As a heat carrier in main heating systems, it is used specially prepared water. During preparation, the indicators of carbonate hardness, oxygen content, iron content and pH are normalized in it. Unprepared for use in heating networks (including tap water, drinking water) is unsuitable for use as a heat carrier, since at high temperatures, due to the formation of deposits and corrosion, it will cause increased wear of pipelines and equipment. The design of the TP prevents relatively rigid tap water to the main heating systems.

Secondary heating networks have a relatively small length (removal of TS from the consumer up to 500 meters) and in urban conditions are limited to one or a couple of quarters. Diameters of pipelines of secondary networks, as a rule, are in the range from 50 to 150 mm. During the construction of secondary heating networks, both steel and polymer pipelines can be used. The use of polymer pipelines is most preferable, especially for hot water systems, since hard tap water in combination with elevated temperatures leads to intense corrosion and premature failure steel pipelines. In the case of an individual heating point, there may be no secondary heating networks.

The source of water for cold and hot water supply systems are water networks.

Thermal energy consumption systems

In a typical TP, there are the following systems for supplying consumers with thermal energy:

Schematic diagram of a heat point

The TP scheme depends, on the one hand, on the characteristics of thermal energy consumers served by the heating point, on the other hand, on the characteristics of the source supplying the TP with thermal energy. Further, as the most common, TP with closed system hot water and independent scheme connection of the heating system.

Schematic diagram of a heat point

The coolant entering the TP by supply pipeline thermal input, gives off its heat to heaters DHW and heating systems, and also enters the consumer ventilation system, after which it returns to return pipeline thermal input and is sent back to the heat generating enterprise through the main networks for reuse. Part of the coolant can be consumed by the consumer. To make up for losses in primary heat networks, at boiler houses and CHPPs, there are make-up systems, the coolant sources for which are water treatment systems these enterprises.

Tap water entering the TP passes through the cold water pumps, after which, part cold water sent to consumers, and the other part is heated in the heater first stage DHW and enters the circulation circuit DHW systems. In the circulation circuit, water with the help of circulation pumps hot water supply moves in a circle from the TP to consumers and back, and consumers take water from the circuit as needed. When circulating around the circuit, the water gradually gives off its heat and in order to maintain the water temperature at a given level, it is constantly heated in the heater second stage DHW.