XII Международная студенческая научная конференция Студенческий научный форум - 2020

Nowadays, in the field of heat supply, there are two oppositeand constantly conflicting parties. Service providers complain about the low level of payments for utilities, while consumers complain about the unreasonably high cost and low quality of the services provided, at the same time the manufacturers claim that this field is unprofitable and the collected funds are not enough for the reconstruction of utility networks . However, world experience shows the opposite.

Currently, one of the significant cost items when paying for utilities is the line associated with heating. Most of the operating central heating systems of residential and industrial buildings do not meet modern standards and technical solutions adopted for similar systems in highly developed countries. Systems that should be operating without disruption for at least 50 years, under local operating conditions, fail after 10-20 years, and in some cases even earlier.

First of all, it is necessary to determine the main areas of wasteful spending. Often, when solving such a deep task, one has to deal with trivial street heating, due to poor thermal insulation on trunk lines, excessive consumption of thermal energy, increased resistance to circulation of the coolant and, as a result, increased energy consumption for operating pumps, premature corrosion of pipelines and components, and the inability to regulation and removal of air from the systems, blocking deposits of pipelines of the smallest diameter and, ultimately, the termination of circulation of the coolant. Until recently, the only known method for changing the situation was the complete replacement of pipelines and furtherassociated components.

Filling the system with poor-quality water leads to early corrosion of all steel elements of the heating system, thinning of the wall thickness and the appearance of fistulas, but mainly this leads to contamination of the system by precipitation. Unlike boilers and heat exchangers, in which precipitates form mainly calcium and magnesium salts precipitated from hard water during its heating, deposits are formed in central heating systems, which consist of corrosion products, iron oxides dissolved in water, to various degrees oxidation. These sediments form a slurry of small or large layers that are closely adjacent to the walls of the metal and have the appearance of rusty-brown growths, which are black below. These corrosion products, having a low dead weight, with increased humidity, gradually occupy an increasingly large volume, gradually blocking the pipeline, which, in the end, leads to the cessation of water circulation and, as a result, to underheating of the premises.

Of all the existing methods associated with the preventive service of maintaining thermal equipment in working condition, in Russia, traditionallyfor decades, the following are used:

- mechanical cleaning;

- chemical (acid) washing;

- hydraulic (hydropneumatic) flushing.

 These methods have a fairly low efficiency and significant limitations on the application. The main limitation on the application is that the methods can only be used during the off-season period when the coolant is not supplied to the heating plant.

In addition to improving the washing method of heating networks and heat exchange equipment, the reagent with which the object is washed is highly important. Currently, the most popular sludge removal method is chemical (acid) flushing. In addition to environmental danger, acids negatively affect pipes, as they react to metal and other materials in the heating system, which leads to its premature failure.

Experts have come up with a completely new method of flushing heating systems and heat exchange equipment, which is efficient, economical and at the same time safe. It will allow to carry out work in the heating period, and the reagent should work equally effectively both in the heating period and in the summer, in a short time: 1 house in 1-3 days. This washing method got its own name - the dispersed method.

Dispersed flushing

This is an innovative way to flush heating systems. The difference between dispersed washing and chemical washing lies in the fact that during dispersed washing, the reagent penetrates into the structure of deposits and weakens the mechanical bonds between the molecules of the deposits without entering into a chemical reaction with the metal of the system itself.

Advantages of the innovative reagent:

- the reagent is 10 times more effective than analogues;

- disinfects the system;

- extends the service life;

- creates a protective hydrophobic film;

- does not destroy the system;

- reduces hydraulic resistance;

- environmentally friendly.

The flushing technology is as follows: a circulation pump is connected to the heating system, the reagent is charged in the calculated amount, and the system is turned on for circulation. The reagent disperses (penetrates) into the sediment, weakens the mechanical bonds of the sediment at the molecular level and is washed off by the flow of coolant. As the solution becomes contaminated, it is washed off into the sewer. Dispersed washing of heating can also occur in the winter, without violating the temperature regime. To do this, an external heat exchanger is installed, which provides a closed circuit of the building heating system by heating from a centralized network.

An important advantage of the dispersed method is the fact of the formation of a hydrophobic film, the “plastic tube effect”, when after washing the pipes do not precipitate metal salts and iron oxides are not formed within three years. This allows us not to flush the house networks during the preparation for the heating period for three years, thereby saving money by redistributing them to other energy efficiency measures.

The use of dispersed washing in open heat supply systems allows you to work all year round without violating the thermal regime. This innovative reagent is absolutely harmless for metal products - pipes, valves, heating appliances and non-metallic parts - seals, valves, safe for biological treatment plants. Oxides and metal salts do not react with the liquid, but loosen, separating from the inner surface of the pipelines in the form of a fine fraction, which does not block the system. The treatment of the heating system acts in a complex way: it removes deposits and creates a protective hydrophobic film that does not allow the formation of new deposits, reduces the hydraulic resistance of the system and lasts for three heating seasons.

It should be noted that during the scientific work, scientists studied various regions of Russia and came up with the “Regional Deposits Map”, which allowed us to conclude that deposits in the form of iron oxides prevail in the Russian Federation, but there are regions in which metal salts are more present. Based on this knowledge, a reagent was created. Currently, the "Regional sediment map" is constantly updated and is being finalized. Flushing of heating systems should be carried out in a package of measures to improve the energy efficiency of buildings. Adjustment of heating systems will not achieve the stated performance without cleaning the system, and flushing without subsequent adjustment will not bring any savings.

The use of only the pipe washing method gives already a significant effect for public utilities.

After flushing the systems with a reagent, experts noted the effective operation of all heating devices, the throughput of heating systems increased by 24-34%. This means that after adjusting the heat transfer of heating systems, in the new heating period, residents of the houses can receive real savings.

There are also a number of innovations, the use of which will really allow us to eliminate the inefficient overspending of resources:thermomizer, heat pumps, air recovery system.

Thermomizer

Now more and more owners of various enterprises are thinking about energy conservation issues. The easiest option for saving is installing meters. But you can go further in this matter. A new product has appeared on the market of energy-saving equipment - a thermomizer. It can be used in almost any heating and hot water supply system. Thermomizers are designed to automatically control the temperature of hot water in water supply systems and the temperature of the coolant in heating systems. Using the device, you can create the necessary microclimate for a particular room. In addition, the thermomizer allows you to save the expense of the primary coolant, and, therefore, cash.

The savings obtained by installing the thermomizer are due to two factors.

Firstly, if after passing through the heating system the coolant retains a high temperature, it is again activated by the system, and does not go to the heating plant. Recycling the coolant gives an undeniable advantage, since ensuring the required temperature requires a much smaller amount of primary coolant than without the use of a thermomizer. This option is suitable for residential, public and administrative buildings.

Secondly, thanks to the thermomizer, we can set the temperature of the coolant we need at a time when the room is not in use. Thus, there is a reduction in the consumption of thermal energy, and, consequently, its savings. If necessary, the cross-section of the regulator on the line decreases, and the temperature of the carrier drops to the minimum allowable. By installing a thermomizer, you can reduce the temperature of the coolant at night. Thanks to the control device, you only need to enter the parameters you need, and the thermomizer will save heat carrier consumption.

The advantages of the thermomizer are not limited to saving money. Thanks to the device, it is possible to maintain the required temperature indoors. For the work of many enterprises, offices and shopping centers, the creation of a certain microclimate is of great importance.

 The practice of implementing energy-saving projects in the field of housing and communal services shows: savings in heat consumption when using a thermostat can reach 50-60%, which will reduce the payment for heat consumed by 30-40%.

The average cost of a domestic thermomizer is 25,000 rubles. The introduction of these devices is justified for enterprises, office and shopping centers, as well as apartment buildings.

Heat pumps

These devices are compact heating systems designed for autonomous heating and hot water supply of residential and industrial premises. They are environmentally friendly, since they work without burning fuel and do not produce harmful emissions into the atmosphere, and are also extremely economical, since when supplying a heat pump, for example, 1 kW of electricity, depending on the operating mode and operating conditions, produces up to 3-4 kW of thermal energy.

The economic efficiency of using heat pumps depends on:

- temperature of a low potential source of thermal energy;

- the cost of electricity in the region;

- the cost of thermal energy produced using various types of fuel.

The use of heat pumps instead of traditionally used sources of thermal energy is economically advantageous in view of:

- lack of need for the purchase, transportation, storage of fuel and the expenditure of funds associated with this;

- the release of a significant territory necessary for the placement of the boiler room, access roads and a warehouse with fuel.

Installation does not violate the integrity of the interior and the concept of the facade of the building, as there is no indoor and outdoor unit and takes up a minimum of space.

Heat pumps are not cheap equipment. The initial cost of installing these systems is slightly higher than the cost of conventional heating and air conditioning systems. The price of a geothermal heat pump is calculated from the condition300-400 USD per 1 kW of thermal power. However, if we consider operating costs, the initial investment in geothermal heating, cooling and hot water supply quickly pays off due to energy saving.

In addition, it must be borne in mind that when operating the heat pump, no additional communications are required, except for the household electrical network.

Air recovery system

After the previous stages have been successfully completed and the heat has effectively got into the home, it is necessary to correctly dispose of them.

Air recovery is the process of heating cold supply air with a removable warm exhaust air. Warm air in a heat recovery heat exchanger transfers most of its heat to the supply air, so that warm air does not come out without use through an open window.

During construction, they use the best materials, thermal insulation, put tight windows, doors and other structures. That is, in the fight for saving heat, we create airtight rooms into which the outside air does not penetrate at all. But we need to breathe. And breathe fresh clean air.
The ideal solution to this issue is ventilation devices that allow you to keep warm in winter and cold in summer. Such devices are called - air recuperator. It is recuperators that fit into the common goal - to make each new building energy efficient. Only here, air recuperators have one disadvantage - the supply and exhaust ducts must be held together to the installation site of the recuperator. Of course, this is not interesting for the end customer, but the designers of Heating, Ventilation and Air-conditioning systems do not like to lay systems in projects that use supply and exhaust heat exchangers.

This factor is one of the main brakes in the widespread distribution and use of highly energy-efficient supply and exhaust systems with air recovery. In this connection, we recommend that end customers are forced to seek the inclusion of air recovery systems in projects. So, let's take a look at this process.

The principle of recovery is simple: since exhaust ventilation throws warm air into the street, we can heat it with cold supply air.

 Exhaust air removed from the room passes through a special heat-exchange cassette in which it heats the walls of the heat exchanger cooled by the supply air.

It is worth noting that the supply and exhaust flows do not mix, but only transmit or take heat from the walls of the heat exchanger.

Lamellar recuperators have one serious drawback, which manifests itself in the form of ice formation on the heat exchanger plates from the side of the exhaust air flows. Ice is formed by freezing of condensate. And condensate is formed due to the temperature difference between the supply air and the heat exchange plate.

The exclusion of the recuperator’s operation when the supply air bypasses the heat-exchange cassettes, as well as the use of not one, but two or even four cassettes in one installation, made it possible to achieve a heat recovery efficiency of up to 91%, which is a revolutionary indicator in the field. Supply and exhaust units operate efficiently even at temperatures up to -30 °C.

This list of innovations in the field of heat supply is far from complete. However, even the implementation of the proposed areas will save from 40 to 60% of consumers money.

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