Thermal substations

What are individual heating points

An individual heating station (ITP) is, first of all, a complex engineering and technical solution, which includes a set of heating equipment and pipeline fittings, united into a single system, which serves for:

• creation of a connection to the circuit of a heat energy supplier (heat generator), which is necessary for organizing heat supply at a separate facility (building or structure);
• creation (wiring) of separate heat supply circuits at the facility (water heating, "warm floor" and (or) hot water supply);
• ensuring efficient, economical and trouble-free operation of the heat supply circuits of the facility.

The parameters and conditions for connecting a specific object (consumer) of heat supply to a supplier (source) of heat energy are in many ways special. Such a heating point is therefore called individual, because it is designed (selected) for the specific conditions of connection and operation. But for generally the same type of connection and operation conditions, typical sets of heating equipment are often created, mounted on a single frame structure. Such typical ITPs are also called block, or modular.

By the type of connection created to the heat supply source, ITP can be:

1. with a dependent connection, when the intake of the heat carrier for heating the object is made directly from the supplier's circuit (heat generator). This type of connection is distinguished by comparative structural simplicity and low cost, it is most common in autonomous heating systems for objects, where the consumer can adjust (configure) the operating modes of not only the heat supply network, but also the heat generator (water boiler, heat pump, solar system, etc.).
2. with an independent connection, when the heat carriers of the circuits of the supplier (heat generator) and the consumer of thermal energy do not mix with each other, and contactless heat exchange between them occurs in a heat exchanger from the ITP set. This type of connection is recommended for organizing heat supply to a separate object from the central heating network, and is characterized by less dependence on the parameters of the coolant in the supply line. Although it is more complicated and more expensive than an independent circuit, it allows a wider range of settings for operating modes, and is able to recoup its purchase in a short time by achieving high technical and economic indicators (saving thermal energy) during operation.

The heat carrier in the contour of the object - the consumer of heat supply without fail is water, which is determined by the structure of household consumption of heat energy (water heating and hot water for sanitary and hygienic needs). For the circuit of a heat energy supplier (heat generator), there are options: it can be either the same water or a steam-gas medium. Accordingly, ITPs by their design can be designed to interface with water or steam-gas boilers.

Typical composition of modular ITP

The design of a (modular) individual heating point means its composition (complete set) and the implemented scheme of connection to the circuit of the supplier (generator) of heat.

Regardless of the implemented connection scheme, a modern ITP usually includes:

• a set of necessary pipeline fittings for organizing the "wiring" of the heat supply circuits of the supplier and the consumer;
• circulation pumps to ensure the required operating pressure and forced circulation of heat carriers in the heat supply circuits of the facility;
• a system for protecting heating equipment from overheating and overpressure, as part of safety valves and bursting discs;
• a heat supply control system, which can be automated or computerized (programmable), as well as manual (on modern heating technology, this is usually a back-up, or emergency control system). A modern ITP control system, as a rule, includes: control valves (usually with electric servo drives), means of objective control (temperature sensors and pressure sensors), computerized controllers or analog electrical control panels;
• heat meter, for organizing the accounting of the amount of actually consumed thermal energy;
• means of visual control (thermometers and manometers) and manual (emergency) control of the ITP operation modes (valves, valves, taps).

For the scheme of independent connection of the heat supply of the object, a heat exchanger is mandatory included in the ITP. In modern autonomous heat supply systems, highly efficient and small-sized plate heat exchangers are increasingly used, which have a very high heat transfer efficiency (up to 90 - 95%), which are gradually replacing outdated boiler-type heat exchangers.

Typical connection diagrams (schematic diagrams of modular heating points OPEKS Energosystem)

Modular heating station.
Scheme with one-stage parallel connection of heaters
(MTP-GV-1-XXX)

The simplest and most common is the scheme with a single-stage parallel connection of hot water heaters. The hot water heater is connected to the same heating network as the building heating systems. Water from the external water supply network is supplied to the hot water supply heaters. In them, it is heated by network water coming from the supply pipeline of the heating network.

The cooled network water is fed into the return pipe of the heating network. After the hot water supply heaters, the heated (hot) tap water is directed to the water supply devices of the buildings. If the water taps of the buildings are closed, then part of the hot water, through the circulation pipeline, is again supplied to the hot water heaters.

This scheme with a single-stage parallel connection of hot water supply heaters is recommended if the ratio of the maximum heat consumption for hot water supply of buildings to the maximum heat consumption for heating buildings (QPg.w. / QPо) is less than 0.2 or more than 1.0.

This scheme is used with a normal temperature schedule of supply water in heating networks.

Rice. 1 Scheme with one-stage parallel connection of heaters.

Modular heating station.
Scheme with two-stage mixed connection of heaters
 (MTP-GV-2-XXX)

The scheme with two-stage mixed connection of hot water supply heaters is more versatile. This scheme can be used both with normal and with an increased temperature schedule of supply water in heating networks and is applied at any ratio of the maximum heat consumption for heating buildings.

The heating of tap water is carried out by network water from the supply pipeline of the heating network. The cooled network water is fed into the return pipe of the heating network. There it mixes with the network water (from heating and ventilation systems) of buildings and enters the first stage hot water heaters.

Fig 2. Scheme with two-stage mixed connection of heaters.

Modular heating station.
Schematic diagram of the heating system, independent (МТП-СО-НЗ-ХХХ)

The module is designed for independent connection of the local heat supply system to an external heat source. One-stage connection module to external heating networks. The circulation of the coolant in an independent circuit is carried out by a circulation pump. The pump is controlled automatically by the heating controller.

Automatic maintenance of the required temperature schedule in the heated circuit is also carried out by an electronic controller. The controller acts on an adjustable valve located on the supply line.

Fig 3. Schematic diagram of the heating system, independent.

Modular heating station.
 Schematic diagram of the heating system, dependent (МТП-СО-З-ХХХ)

The module is designed for dependent connection of the heating (ventilation) system to external heating networks. The circulation of the heating agent in the heating circuit is supported by a circulation pump. The pump is controlled automatically from the heating controller.

Automatic maintenance of the required temperature schedule in the heating circuit is also carried out by an electronic controller.

The controller acts on an adjustable valve located on the hot water supply line.

Fig 4. Schematic diagram of the heating system, dependent.

Possibilities of modern individual heating points

Until recently, ITPs were mainly used to connect apartment buildings and large office buildings to the district heating network. But in modern conditions, with the development of highly efficient small-sized heating equipment, control and automation tools, and their significant reduction in cost, ITPs are widely used in autonomous heating schemes for private houses, retail outlets, small workshops, and office premises.
 The capabilities of a modern modular ITP in terms of functionality and efficiency are impressive:

• a highly efficient plate heat exchanger provides an efficiency of up to 90 -95%, due to which the overwhelming amount of heat taken from the supplier (or from an autonomous boiler) goes into the heat supply network of the object, and does not dissipate in space;
• the built-in heat meter guarantees an objective control over the amount of consumed heat, and makes it possible to organize its savings based on the results of control;
• Automation tools allow you to establish and stably maintain economical energy consumption modes, automatically optimize the operation of the heat supply system of the facility, with appropriate savings in thermal energy, depending on the ambient temperature, time of day (day or night), seasonality and the presence of people at the facility (heated / unheated season , working or non-working hours, departure / arrival on vacation, etc.) or in general in accordance with a given program;
• the ability to automatically control the connection of several autonomous heaters to the object's heating network at once (for example, gas, electric, solid fuel boilers, heat pump, solar system).

Technical characteristics for the selection (selection) of individual heating points

The choice (selection) of the design of a modular individual heating unit is possible according to the following options:

• in the process of design (complete redesign) of the heat supply system of the facility, according to the requirements of the technical assignment;
• in the process of partial reconstruction of the heat supply system, according to the requirements of the technical assignment and the existing connection conditions;
• when replacing an outdated or out-of-order heating point with a new (modern) one - according to the existing connection conditions.

The main parameters for the selection (selection) of a modular ITP are:

A) according to the characteristics of the heat supply source and the installation conditions:

• heat supply source - central heating network, autonomous heat generator (boiler), or other options;
• structure of heat consumption: only water heating, hot water supply, ventilation, or in a complex;
• working pressure in the supply and return pipelines;
• operating temperature in the supply and return pipelines;
• existing restrictions on dimensions;

B) according to the characteristics of the heat supply system:

• connection diagram: dependent or independent;
• required heat load (power), Gcal / h;
• operating temperature of the water in the circuit, at the inlet and outlet;
• maximum allowable pressure in the circuit;
• the volume of the coolant in the system, m ³ ;
• hydraulic resistance of the system;
• the height of the highest point of the system, in m.

Advantages of ITP manufactured by OPEKS Energosystem

The main advantages of purchasing modular individual heating points manufactured by OPEKS Energosystems are:

• the company has many years of experience in the design and manufacture of the most complex heating systems for various purposes, a high production culture and an established quality control system, due to which our ITPs are characterized by a very decent level of engineering excellence and manufacturing quality;
• the accumulated indisputable authority and business reputation of the company, the won leadership positions in the regional market, which is the best evidence of the high quality of our products;
• our desire to keep pace with the latest achievements and developments, thanks to which our ITPs in their capabilities meet the most modern trends in the industry;
• the presence of our own production of many components of the ITP design, which has the most favorable effect on their prime cost and selling price. Our ITPs combine undeniable quality and very affordable cost.