Creating an optimal indoor microclimate and providing comfortable conditions for living and working is not only a requirement of sanitary standards, but also a guarantee of people’s health. At the same time, it is important to take into account the economic factor so that heating the building and providing hot water supply can be achieved with minimal financial costs. In order to save coolant, carry out flexible adjustment of indoor microclimate parameters and heat metering, individual heating points are installed (the abbreviation is more often used, the decoding is ITP).
What is ITP? This is a complex consisting of elements of thermal installations, ensuring the distribution of coolant between consumers with the ability to adjust its parameters (temperature, supply modes, etc.) and metering. This complex is located in a separate technical room, and the heating units are connected to the heating network (central transformer substation, combined heat and power plant or boiler house). With the help of IHP, heating, hot water supply (hereinafter referred to as DHW) and ventilation can be provided. In multi-apartment residential buildings, ITPs are most often located in basements; it is also possible to install equipment in extensions to buildings or in separate technical structures (practised in industrial enterprises).
Currently, new houses are increasingly being designed taking into account the need to install IHP; in old buildings, procedures are being carried out to modernize heating networks, allowing the installation of heating points (TS). This popularity is explained by the benefits that ITP provides to end consumers, including:
- Significant (up to -40%) reduction in coolant consumption and consumer costs for heating and hot water supply.
- Protection of internal networks from increased temperature or pressure of the coolant.
- Ensuring operational safety and low accident rate.
- Providing accounting for the amount of coolant consumed.
- Full automation of IHP control with the ability to remotely regulate coolant supply modes (external temperature conditions, seasonality, time of day, etc. can be taken into account).
- Possibility of installing ITP of various types in almost any building.
Principle of operation
The operating principle of IHP in any building depends on the source of coolant. Usually they are served by an autonomous boiler house or thermal power plant, a combined heat and power plant (CHP). The heat source is connected to the heating point through the main heating network, and the heating substation is connected to the end consumers through secondary distribution heating networks. Having given the heat to consumers, i.e. Having ensured the operation of the hot water supply system and heating system, the coolant returns through the return line to the heat supply enterprise. There it is recharged and heated to a given temperature, after which it is again supplied through the main heating networks to the heating point and then distributed among consumers.
If a heating and power plant acts as a heat source, then the temperature of the coolant supplied to the heating point from large suppliers is, as a rule, 150-70oC, 130-70oC, 115-70oC (two numbers - the temperature of the supply coolant and the return temperature). In order to lower the temperature of the supplied coolant to a level acceptable to consumers, there are 2 options:
- With an independent connection, plate heat exchangers (HE) are used - the coolant (water) from the heating network circulates through them, heating the internal closed network.
- With dependent connection (this type is considered obsolete), elevator units are installed or pumps are used that mix the coolant from the return line to the supply line.
Coolant circulation is ensured by circulation pumps. Pressure regulators protect the complex from an emergency increase in pressure in the network. The specified temperature of the coolant supplied to consumers in modern transformer substations is ensured using automation: the heating station operator sets the required values or selects the ITP operating mode (for example, with a decrease in temperature at night).
A mandatory element of any heating station is a heat metering unit. With its help, the amount of coolant consumed is recorded. Due to the presence of a meter, the consumer has the opportunity to pay only for the resource actually consumed by him: with the modernization of the heating network and the rational consumption of heat, the amounts in payments for heat are significantly reduced.
Literature
- Sokolov E.Ya.
District heating and heating networks: a textbook for universities. — 8th ed., stereot. / E.Ya. Sokolov. - M.: MPEI Publishing House, 2006. - 472 p.: ill. - SNiP 2.04.07-86 Heat networks (ed. 1994 with amendment 1 BST 3-94, amendment 2, adopted by Resolution of the State Construction Committee of Russia of October 12, 2001 N116 and the exception of section 8 and appendices 12-19). Heating points.
- SP 41-101-95 “Code of rules for design and construction. Design of heating points".
| Energy structure by products and industries | |||
| Electrical power industry: electricity | Traditional | Thermal power plants | Condensing power plant (CPS) Combined heat and power plant (CHP) |
| Hydropower | Hydroelectric power plant (HPP) Pumped storage power plant (PSPP) | ||
| Nuclear | Nuclear power plant (NPP) Floating nuclear power plant (FNPP) | ||
| Geothermal power plants (GeoTES) | |
| Hydropower | Small hydropower plants (SHPPs) Tidal power plants (TPPs) Wave power plants Osmotic power plants |
| Wind power | Wind power plants (WPP) |
| Solar | Solar power plants (SPP) |
| Hydrogen | Hydrogen power plants Fuel cell plants |
| Bioenergy | Bioelectric power plants (BioTES) |
| Small | Diesel power plants Gas piston power plants Low power gas turbine plants Gasoline power plants |
District heating has a number of obvious advantages, as well as disadvantages. The main negative feature of centralized systems is the extreme cumbersomeness of the system and the inability to adjust the operating parameters of the system to a specific home. Not to mention the fact that designing engineering systems of this scale is an extremely labor-intensive process and does not always allow achieving the specified efficiency parameters.
ITP for a single building
Designed to serve one residential building, administrative building, industrial premises. When designing ITP, ready-made block heating units can be used.
TsTP - central TP
They are designed to provide heating and hot water supply for microdistricts, several buildings, and large industrial enterprises. When creating central heating stations, block heating points can be used. Houses and buildings with ITP installed in them can be connected to the central heating point.
BTP - block heating point
BTP, or block heat substation, is a product completely ready for commissioning, which is used to create an ITP or central heating substation. The BTP is supplied assembled and is quickly connected to the heating network using flanges. To significantly reduce the costs of designing and installing an IHP or central heating point and simplify the design of the heating point itself, it is enough to buy a block heating point from a company specializing in the sale and maintenance of heat exchangers and BTP.
Schematic diagram of ITP
When designing ITP, the following equipment is used:
- Circulation pumps,
- sensors,
- controllers with t sensors,
- control valves on electric drives;
- control units,
- shut-off and control fittings, valves.
The simplest circuit diagram of an ITP designed using this equipment is as follows:
In dependent and independent schemes for connecting the heating system to external mains of the heat supply organization, different equipment is used.
The ITP diagram for dependent connection of the building’s heating system to the heating networks of a thermal power plant or boiler house is as follows:
Water circulation is ensured by the operation of pumps controlled automatically by a control unit or controller. The set temperature regime is maintained by controlling the control valve. In the scheme under consideration, the temperature regime of the circulating water can be adjusted using a jumper with a check valve. It allows you to mix cooled coolant from the return line with hot water. An alternative is the option with an elevator unit.
The ITP diagram with an independent connection type is shown below:
The main feature is the use of a heat exchanger and special filters for cleaning and preparing the coolant for entry into the maintenance facility and the intra-house heating network. Coolant circulation is also carried out using pumps controlled automatically using a control unit or controller.
The recommended form of specifications is given in Appendix No. 10.
Specifications are compiled based on the subscriber's request. TCO indicates data on maximum thermal loads in the technical specifications. The subscriber generates data on heat loads based on an energy survey of the building, designs of internal heat consumption systems or, in their absence, on the basis of heat consumption system passports calculated using aggregated indicators. When drawing up technical specifications, TCO is also guided by its own data on the heat supply area.
Thermal loads must be calculated by a specialized design organization; TSO is obliged to check and approve the calculation.
- Terms of reference (TOR)
The technical specification is developed by the organization planning the arrangement of the ITP (customer), or by a specialized (having an SRO certificate of admission to these types of work) design organization (contractor) on behalf of the customer and must contain:
- Name of the customer organization;
- Name of the subscriber (if the subscriber and the customer are different organizations);
- Purpose of the object;
- Data on connected thermal loads, their distribution among systems;
- Name of TSO, TU No.;
- Staged design (design or working documentation, or sequential implementation of two stages);
- Design Boundaries;
- The need to develop, as part of the ITP project, passports for heat consumption systems to determine their thermal and hydraulic parameters or use available data from existing passports of internal systems or use values obtained during the survey;
- Guaranteed cold water pressure at the inlet to the ITP;
- Brands of main equipment (control valves, heat exchangers, pumps, controller, etc.) preferred when designing ITP, if this does not contradict the current legislation of the Russian Federation;
- The need for redundancy of heat exchangers and pumps (if technically possible);
- The need to install or reconstruct a heat metering unit (to be carried out as a separate project in accordance with the current regulatory and technical documentation);
- Data on power supply (voltage, number of phases, approximate distance of the ITP from the main switchboard);
- List of initial data provided by the customer to the contractor;
- Requirements for project approval and approval procedure;
- Additional requirements for arranging ITP;
- Time frames for the design of ITP.
The terms of reference must be approved by the head of the customer organization, contain the date of signing by the parties and seals of the parties.
The terms of reference are an integral part of the design contract and are drawn up in 2 copies, one for each party.
The requirements of the technical specifications should not contradict, but may complement the requirements of the technical specifications.
How the thermal unit works
The design of each heating unit depends on the customer's requirements. In practice, several schemes are used:
- Thermal unit based on an elevator. The simplest scheme, which is considered obsolete, the main disadvantage of which is the inability to flexibly regulate the temperature of the coolant, especially during transitional temperature conditions (if it is from +5 to minus 5C outside). Consequently, saving coolant also turns out to be inaccessible. In the elevator unit, the coolant from the main network is mixed with water from the return line, thereby achieving an acceptable temperature for supply to consumers. Mixing is carried out according to the principle of ejection due to the presence of a nozzle of a certain diameter in the design of the elevator unit.
- Thermal unit based on a plate heat exchanger. A modern and effective version of the design of a thermal unit, in which real savings in coolant and flexible adjustment of its temperature and pressure are possible. Such a TP allows you to separate the coolant entering through the heating main from the coolant that moves through the intra-house networks. Due to this separation, it becomes possible to prepare the coolant by adding special additives to it and filtering it, as a result, you can safely install aluminum radiators in houses. With this scheme, the coolant is mixed through the operation of thermostatic valves. In a similar way - i.e. through heat exchangers - DHW can also be connected.
Main types of heating points
Thermal units, through which the heating system, hot water supply system and ventilation are connected to a source of thermal energy, are of two types: single-circuit and double-circuit. Let's take a closer look at each of them.
Single-circuit TP
In this case, the heating system of a residential building, administrative or industrial building is directly connected to the DHW main. A distinctive feature of this type of heating points is the presence of an elevator unit - a pipeline connecting the forward and return lines. It was the single-circuit TP circuit that we considered above when we were talking about a thermal unit based on an elevator. Note that such a scheme may involve the installation of an additional circulation pump, or a special form of main pipes is used - first there is a sharp section of narrowing, and then a cone-shaped expansion, as a result of which water from the return line is pumped into the network (the principle of ejection works).
Double-circuit heating point
This scheme was discussed above when talking about a thermal unit based on TO. A plate heat exchanger is a device consisting of a number of hollow plates, along one of which the heated liquid (water) moves, and along the other – a heating liquid (water). By changing the number of plates interacting with each other, it is possible to regulate the amount of heat removed so that additional intake from the return is not required. Heat exchangers have high efficiency and are reliable and unpretentious equipment.
Where does the noise come from?
Vibration of pump casings, boilers and pipes creates airborne noise. It enters the apartment via a frame. When equipment comes into contact with a building, vibrations are created, which are transmitted from the metal to the concrete, and then to the living space. The noise transmission channels are: metal studs on which the pipes are held; brackets near the walls along the pipe laying; non-vibration-insulating mounting of equipment to the floor.
However, when using modern heating units, complete noise insulation is ensured. The noise does not disturb the peace of residents and complies with all SNiP (building codes and regulations). Thus, noise pollution in the area is reduced. This result is achieved due to the fact that:
- Pumps are connected to pipelines with flexible anti-vibration rubber inserts;
- The pumps have a low noise level;
- Rubber-metal supports are used between the pump frame and the floor;
- There is a gap between the surface of the insulation pipe structure and the building structure. Tight sealing of pipes into the walls of a building is unacceptable.
Installation steps
To put a heating point into operation, you need to go through several stages:
- Submitting an application to a specialized company for the design of a TP.
- Development of technical specifications.
- Obtaining technical specifications (TU).
- Direct design of the TP and approval of the project.
- Concluding an agreement with a heat supply company.
- TP test.
If we are talking about ITP in an apartment building, then the very first stage is obtaining the consent of the owners of the apartments of the building to install the equipment (the issue can be submitted to a general meeting). The following package of documents is submitted to the regulatory authorities:
- Specifications for connection;
- certificate from the heat supply organization;
- agreed project;
- passport of the installed ITP;
- certificate of the fact of concluding an agreement with the heat supply organization;
- act of permission to commission installations;
- other documents (the complete list may differ in each region).
What does the cost depend on?
For efficient operation of IHP, it is important to calculate heat losses at the design stage, taking into account the individual characteristics of each room. Often the efficiency of a heating point depends on a certain sequence of equipment in the circuit.
The cost of ITP consists of taking into account various factors:
- Number and load of energy consuming systems.
- Difficulty of operation and functioning in given conditions.
- Total thermal load.
- Price for selected equipment.
You may also be interested in seals and plates for heat exchangers.
ITP of an apartment building
The operation scheme of the ITP of a residential high-rise building does not differ from the standard scheme for a single building. Sometimes, instead of ITP, the abbreviation AITP is found - automated heating point; it is assumed that in it the parameters of the coolant, operating mode, etc. can be adjusted using electronics.
The ITP of an apartment building is connected to the main heating network. Heat to the ITP comes from the boiler house, central heating substation or from the combined heat and power plant. The ITP distributes it between the heating, hot water supply and ventilation systems (if it is connected to the ITP).
When installing ITP in a residential building, residents receive the main advantage - savings on housing and communal services. By adjusting the temperature and the amount of coolant consumed, taking into account the outside temperature and even the time of day (at night, during sleep, you can slightly reduce the temperature), you can reduce the cost of paying for the services of heat supply companies.
It should be noted that almost all ITPs that are now installed in apartment buildings are automated and operate on heat exchangers, which ensures maximum accuracy in adjusting the coolant temperature and almost 40% savings.
Which is better: ITP or TsTP?
Central heating stations are installed where it is necessary to provide heat to several buildings at once. ITP is designed to supply heat to one building or residential building. Hence the main differences between them. ITP is designed to solve a specific narrow problem, therefore, like any individual solution, it has more advantages. These include:
- Possibility of setting a specific heating temperature for each building. If we are talking about central heating stations, then most often those buildings that are located closer to the boiler room turn out to be overheated, and those further away, on the contrary, do not receive enough heat.
- Elimination of heat loss in the pipelines of the hot water supply system and the heating network (the heat exchanger is located in the same building). When connecting several buildings to the central heating point, such losses are inevitable.
- Reducing the risk of emergency shutdown. If a central heating station breaks down, residents or workers of all connected buildings find themselves without heat and hot water.
- Ease of maintenance and preventive repairs.
Thus, the central heating point and the ITP are designed to solve various problems, however, due to the smaller number of connected buildings and subscribers, the ITP is a more flexible system that provides maximum opportunities for savings.
Operational safety
Modern AITPs provide maximum safety for both the personnel they serve and consumers. The main condition: the heating unit must be serviced by workers who have undergone special training and have the appropriate permits. They should be familiarized with the operating rules of a specific ITP and technical documentation.
The basic rule that should be followed for the safe operation of ITP: pumping equipment and automation are prohibited from starting in the absence of coolant and when the shut-off valves at the inlet are closed. In addition, persons servicing ITP must control:
- Pressure levels on pressure gauges installed on pipelines.
- Noise and vibration indicators (they must be within normal limits).
- Heating of electric motors of installations.
- Flushing the systems before starting the heating station.
It is important to remember that if there is pressure in the system, disassembling the regulators is prohibited and it is also prohibited to use excessive force when manually operating the valve.
Maintenance of UUTE
All responsibilities of the service provider are specified in the contract. The performing company is obliged not only to install the equipment, but also to carry out its maintenance. The UUTE maintenance includes the following activities:
- External inspection is carried out once a month. The main task is to check the integrity of the sealing, fuses, safety of connecting cables, checking grounding;
- metering devices must undergo not only inspection, but also a number of technical actions, such as cleaning filters, checking the operation of electromechanics, automation, wiring integrity, adjusting the operation of the metering system;
- metrological checks are carried out periodically at a special stand in the laboratory. The purpose of the event is to maximize the life of the equipment;
- interaction of work with the organization supplying heat.
The cost of these services is fixed in the contract and cannot be changed throughout the entire period of the contract.
