Improving the efficiency of heating systems. Apartment ventilation system with heat recovery units. Apartment ventilation systems with plate heat exchanger
In addition to the above aspects of passive energy saving, it is also worth mentioning the latest solutions involving high technologies. This approach requires significant and sometimes radical changes to the district heating scheme common in our country. A great effect can also be obtained by partial reconstruction of heating systems.
There are several different ways to improve the efficiency of heating systems in residential buildings, differing both in the amount of costs involved in their implementation and in the limitations of their application.
The most conservative way of energy saving for the option of heat supply from the CHP is the installation in houses on heating devices of individual thermostatic controllers. Studies show that the introduction of integrated automation can reduce the heat consumption of the house as a whole (compared to the elevator unit) by 15–20%. Foreign experience shows that individual heat metering in combination with the ability to control heat consumption gives heat savings of up to 25%. This scheme is currently being implemented in apartment heating systems, for example, in pilot projects.
On the other hand, developers and builders of new residential buildings are increasingly coming to the conclusion about the significant advantages of modern decentralized heating systems over traditional centralized systems. It's no secret that in last years The performance of central heating systems almost everywhere has deteriorated significantly due to chronic underfunding and depreciation of equipment. Therefore, accidents, shutdowns and banal deception of the consumer are frequent, when the pressure and temperature in heating plants are deliberately lowered, and the consumer receives less heat, paying for it regularly. Such negative aspects are minimized in decentralized heating systems.
Another advantage of decentralized systems is flexible power control, which allows you to greatly reduce it or completely turn off the system in case of uselessness, for example, during warming. In addition, the minimum heat loss in heating networks can also be considered an important factor, since heat is consumed in close proximity to the place of its production, that is, in general, decentralized systems have a much higher efficiency than central heating systems.
Another alternative to traditional central heating has recently become electric heating. , which was not previously widely used in Russia and was considered unprofitable (in 1995, less than 1% of the housing stock was heated). At the same time, the share of electric heating in Finland, Sweden and Denmark reaches 50%.
But the attitude towards this type of heating is rapidly changing due to the steady rise in the price of all energy carriers. Moreover, the potential for price growth to world levels is the largest for gas, and the smallest for electricity.
Obviously, because of this, in the last 3-5 years there has been a rapid increase in the number of electric heating systems. For example, in Yekaterinburg during 2000, more than 15% of newly built housing was equipped with cable floor heating systems.
Already, combined electric heating systems are no more expensive to build and operate than a central heating system, and this advantage will only grow with time.
In 2016, private heat consumers in Ukraine receive heat from the following sources: 1. The most common - from electricity, electric boilers, electric fireplaces, electric heaters ... The source without details in most cases is "energy ...
For more than six months I have been studying vacuum solar tubes with a length of 1800 with an outer diameter of 58mm and an inner diameter of 43-44mm. The internal volume of the tube is 2.7 liters. Sometimes, in the active bright sun, the power of the tube showed about 130-150W, but ...
Closed geothermal systems providing only hot water. Depending on the location of the discharge site and the source of drinking water, three types of circuit solutions can be used. Scheme (Fig. 2.6.). Geothermal water is supplied…
Thermal efficiency heating device in the room and the choice of the installed heat output of the heating system.
The heater must compensate for the lack of heat in the room. The use of devices of one design or another and their installation in different places in the room should not lead to a noticeable excess heat consumption. The indicator evaluating these properties is the heating effect of the device, which shows the ratio of the amount of heat consumed by the device to create the specified thermal conditions in the room to the calculated heat loss by the room.
It is believed that panel-radiant devices installed in the upper zone of the room or built into the ceiling structure have the best heating effect. The heating effect of such devices is 0.9-0.95, i.e., the heat transfer of the ceiling panels-emitters can be even slightly lower than the calculated heat loss of the room without compromising the comfort of internal conditions. The heating effect of the panel located in the floor structure is about 1.0.
The most common appliances - radiators are usually installed in niches or near the surface of the outer wall. The intake surface overheats and through this part outer wall some amount of heat is wasted. As a result, the heating effect of radiators is estimated at 1.04-1.06. In this regard, convectors located along the outer wall are more efficient. The heating effect of, for example, a baseboard convector is approx. 1.03.
A window sill panel embedded in an exterior wall structure can have noticeable useless heat losses and its heating effect is reduced to 1.1.
Heating appliances usually have a certain step of the accepted nomenclature range, which in SNiP is expressed by heat transfer, kW, individual element device of this series. As a result, the number of elements of the device is set in the room, rounded up in excess of the calculated value. The associated increase in heat flow from devices is recommended to be taken into account by the coefficient β 1, which varies from 1.02 to 1.13 depending on the change in heat transfer from an individual element of the device from 0.12 to 0.3 kW.
Additional heat loss by a heater installed at the outer fence is taken into account by the coefficient β 2 . Its value, depending on the type of device and the method of its installation at the outer fence, varies from 1.02 to 1.1.
In addition to losses associated with the placement of heating devices, useless heat losses occur in the heating system through pipes built into the construction of external fences, as well as in heating point and other elements of the system. Additional heat losses Q tr pipes in unheated rooms associated with coolant cooling are also determined.
The value of the total additional losses (instrument sections of external fences and heat pipelines in unheated premises) should not exceed 7% of the heating system heat output according to SNiP.
Specific thermal characteristic of the building and calculation of heat demand for heating by integrated meters
For a thermal assessment of space-planning and design solutions and for an approximate calculation of the heat loss of a building, the indicator is used - the specific thermal characteristic of the building q, which, with known heat losses of the building, is equal to:
q = Q zd ∕
where Q zd - calculated heat losses through external fences by all rooms of the building, W; V - the volume of the heated building according to the external measurement, m 3, (t in - t n) - the estimated temperature difference for the main premises of the building.
The value q, W / (m 3 ° C), determines the average heat loss of 1 m 3 of the building, referred to the calculated temperature difference of 1 °. It can be determined in advance
q = q 0 β t
where q 0 is the reference specific thermal characteristic corresponding to the temperature difference ∆t 0 \u003d 18 - (- 30) \u003d 48 ° С; β t - temperature coefficient taking into account the deviation of the actual calculated temperature difference from ∆t 0
The reference specific thermal characteristic can be determined taking into account the requirements of SNiP.
Economic indicators of heating systems
The efficiency of the heating system is due to the cost of materials and equipment, manufacturing and assembly, as well as operation. Economic efficiency indicators are manufacturability of the design, mass of elements, labor costs and terms of manufacture and installation, costs for adjustment, management and repair.
The manufacturability of the design includes such real measures as circuit simplification, unification and reduction in the number of parts, the use of normals, ease of assembly, which provide manufacturing and installation with minimal cost time, money and labour.
The economic effect is revealed during the technical and economic comparison of various design solutions. Comparison allows you to choose the most economical heating system in given specific conditions.
In the economic comparison of options, the following indicators are used: capital investments K, operating costs I, the duration of installation work and operation of the heating system. Usually some of these indicators are used. The simplest is to compare heating systems with different devices, but with one type of coolant and with one scheme, since it is done only for capital investments. Most often, systems are compared in terms of capital investments and operating costs. Less often, the timing of installation and service of systems, the availability of labor reserves are also taken into account.
The most economical option is the one with the minimum total capital investment and operating costs. Usually you have to compare two options, one of which has a lower capital investment, the other has a lower operating cost. So, with a decrease in the diameter of the pipes of a pumped water heating system, capital investments decrease, but electricity consumption increases; automating the system increases capital investment but reduces operating costs. An economically more efficient option is identified in such cases, depending on the period z, years, and the payback of additional capital investments.
Z \u003d (K 1 - K 2) ∕ (I 1 - I 2)
If this term z< z н - нормативного срока окупаемости дополнительных капитальных вложений за счет снижения эксплуатационных затрат, то целесообразно осуществить вариант с большими капитальными вложениями K 1 и меньшими средними годовыми эксплуатационными затратами И 1 . Если z >z n, then the option with lower capital investments K 2 and a higher average cost of operation AND 2 during the year is expedient. The standard payback period z n of investments in the heating system is assumed to be 8.33 years (12.5 years for new equipment and energy-saving measures), regardless of the type of building.
In an economic comparison of several systems or system options, the reduced costs are found for each of them.
3= (K ∕z n) + I,
and, the option that has the lowest reduced costs for the standard payback period is considered more effective.
Capital investments in the heating system are carried out, as a rule, within one year. Operating costs vary annually; in addition, they depend on the service life of both the system and its individual elements.
Annual operating costs consist of direct heating system maintenance costs and depreciation costs
I \u003d I pr + A
where And pr - direct operating costs, consisting of annual costs for the received thermal energy (fuel), electricity, wages of maintenance personnel, system management and current repairs; A - depreciation costs, including annual costs for overhaul systems and deductions for the full recovery of capital investments.
Deductions for the restoration of capital investments are associated with the standard service life of the system, determined on the basis of the terms of physical wear and tear of its elements: radiators (40 years), water conduits (30 years), steam pipelines, centrifugal pumps, valves (10 years), fans, heaters, heating units (8 years), filters (6 years), condensate pipelines (4 years).
The service life is determined not only by the physical, but also by the obsolescence of the heating system, and obsolescence is considered to be the loss of the ability to maintain the temperature in all serviced premises at the required level. The standard service life of common water heating systems is currently assumed to be 30 - 35 years (shorter for convectors).
When comparing various systems heating systems comply with equal or at least close performance indicators for all options: systems must meet sanitary and hygienic, fire and anti-explosion requirements, and must also have equivalent efficiency.
The service life of water heating systems, as already known, is the longest. Due to the reduction of depreciation costs at the same time, the savings in electrical and thermal energy reduce the cost of operation, and, consequently, the reduced costs. Therefore, a hot water heating system usually becomes more cost effective than a steam heating system.
The difference in thermal comfort created in the premises with compared heating systems is taken into account by the change in the service life and the degree of use of the area of the premises. For a system that provides more comfortable conditions, the estimated service life is increased by 5-10 years (considering less obsolescence). In addition, the use of the working area of the premises in the cold season is taken into account (by changing the size of the discomfort zone), adding part of the cost of construction work on the depreciated area to the estimated cost of another system.
Nevertheless, the main indicator of the efficiency of the heating system is the heat consumption during its operation. It is known that only the annual operating costs exceed half the cost of the installation of the system. And the main part of the costs falls on the payment of consumed heat. Heat consumption for heating in a steam or central air system exceeds the heat consumption in a water heating system due to an increase in associated heat losses through the walls of steam pipelines and air ducts that are useless for heating working premises.
Combined heating
It is customary to call combined central heating systems with two heat carriers, when the primary heat carrier (water, steam) is used to heat the secondary one (water, air). Due to the widespread use of centralized water heating in our country, most central heating systems have actually become combined - water-water or water-air.
At present, combined heating has come to be understood as a combination of two operating modes of the system or two systems for heating the same room with a variable thermal regime. The work and design of heating systems are also being improved to improve the thermal regime of premises and reduce heat costs for heating buildings. A structurally similar solution was also encountered earlier, when two heating systems of different capacities were provided for heating a periodically used industrial premises: one for a working period of time, the other (on duty) for a non-working one.
Distinguish combined heating two-mode, two-component, with an intermittent mode.
dual mode called heating, operating at different temperatures of the same coolant at different times of the day. A dual-mode system is a water heating system in which water circulates during the working period at low temperature(for the beneficial use of internal heat generation), and during the non-working period - with increased (or vice versa). To lower the temperature, a mixing pump is turned on; to increase, a direct-flow supply of coolant from an external heat pipeline is used without mixing chilled water.
A dual-mode air heating system combined with supply ventilation during the working period of time, and recirculation during the non-working period. The supply air temperature in the first period is lower than in the second.
Two-component consider heating as two systems that complement each other to provide the necessary heat supply to the premises. The first system, usually water heating, called background or basic, is arranged with a reduced power (for example, 30% of the calculated heat demand of ordinary rooms) for constant unregulated operation throughout the heating season. The task of this system is to equalize the deficit of heat per unit area or volume of ordinary and corner, lower and upper rooms of the same type of the building (artificially create the same specific thermal characteristics of the main rooms).
The second system of water, air, gas or electric heating, called reheating, provide additional power to maintain the required air temperature, both during working and non-working periods of time. The operation of the heating system is automated to work according to a given program.
Combined heating can operate intermittently, and then the thermal regime of the premises is characterized by three states: temperature constancy during working hours, free temperature drop when the heating system is turned off, and heating of the premises before starting work or during holidays(about intermittent heating). Various combinations are also possible listed species combined heating, when two-mode operation of one or both two-component heating systems is provided.
Improving the efficiency of building heating
final stage The algorithm for developing a building with efficient use of energy is to evaluate the efficiency of the adopted heating method as an integral part of the SCM of the building. This is the aim of the engineering techniques discussed in this section.
The complex property of the SCM of a building to effectively perform its functions is usually a probabilistic characteristic. The efficiency of the heating system is determined by three main properties: reliability, controllability (or stability) during operation, security.
Reliability- probabilistic provision of trouble-free operation of the mechanical part of the heating system, its structural units and elements during operation within the estimated terms and conditions.
Controllability- probabilistic maintenance of specified deviations in the operation of individual parts and zones of the heating system in the process of control and operation during the heating season.
security- the maintenance accepted in the project with an acceptable probability of deviations of the design internal conditions in the building.
Heating system regulation
The regulation of the heating system is understood as a set of measures aimed at maximizing the approximation of the heat transfer of its elements to the current variable heat demand of the heated premises during the heating season in order to maintain the design temperature of the premises.
Distinguish starting and operational regulation of the system. These types of regulation have their own characteristics for water, air and steam heating systems.
When starting the heating system of a group of buildings connected to the district heating pipelines, the heat carrier is distributed among individual buildings in proportion to their calculated heat demand. Typically, such regulation is carried out in central heating points (CHP) and in intra-quarter heating networks. Methods of regulation, both with dependent and independent connection of the heating system to heat pipelines, are considered in the discipline "Heat supply".
Start-up regulation of elements and components of the heating system is associated with the provision of the calculated flow rate of the coolant in them.
Operational regulation of the heating system is carried out in order to ensure heat supply to the heated premises corresponding to the current heat demand. The control methods also differ depending on the coolant used in the system. Depending on the place of regulation in the heat supply system, there are central, group, local and individual regulation.
In the water heat supply system, central regulation is carried out at a thermal power plant (CHP, boiler house) according to the so-called heating schedule, which establishes a relationship between the coolant parameters (temperature with qualitative or flow with quantitative regulation) and the outside air temperature as the main factor determining the variable nature of the heat balance components buildings during the heating season
Central regulation at a thermal station for heat supply to buildings of various purposes (residential, public, industrial, etc.) and the mode of heat consumption of their engineering systems (heating, hot water supply, ventilation, etc.) cannot ensure stable operation of heating systems.
The stability of operation increases as the place of regulation approaches the heat consumer due to a more complete consideration of various factors that determine the heat demand of the premises of heated buildings. Thus, with group regulation in the central heating station, it becomes possible to distribute heat according to specified temperature schedules, which contributes to an increase in the efficiency of heating each building. With local regulation in the thermal point of the building, the features of its operation mode, orientation along the sides of the horizon, the effect of wind and solar radiation are taken into account.
Increasing the efficiency of heat networks is an urgent and important task for the Russian thermal power industry. In the energy sector of enterprises and municipalities, the most unreliable and worn-out element is heating networks.
Traditionally, they are given insufficient attention, and the low level of exploitation culture, the impact external factors(including such as vandalism) and the poor quality of the original construction, explains their terrible state at the moment. Accidents often occur on them, which leads to failures in the heat supply to end consumers.
It is widely believed among non-specialists that the operation of heating networks is a simple and unsophisticated exercise. This approach leads to a lack of attention paid to operational issues. Therefore, the state of heat networks, as an element of the entire heat supply infrastructure, is in a very deplorable state. This leads to large energy losses, when up to 80% of the transferred heat is lost in heating mains. Naturally, it is necessary to increase the temperature of the coolant, intensively consume fuel, which disproportionately increases costs.
It often happens that as production expands or a settlement grows, the existing heating network ceases to meet the necessary needs. Sometimes when surveying networks, design errors and performance flaws are revealed. construction works. In thermal networks with a complex structure, it is possible to carry out measures to optimize it, which reduces costs.
In practice, it is the modernization of heating networks that brings the most tangible results. This is due to their very poor condition. Often, heating networks are in such a worn out form that the modernization of boiler houses and heating points does not give the desired effect. However, in such cases, the mere increase in the efficiency of heat networks can significantly improve the quality of heat supply and reduce operating costs.
Technologies for the construction and operation of thermal mains do not stand still. New types of pipes, fittings appear, new heat-insulating materials begin to be used. As a result, the situation begins to slowly improve.
Design, construction, operation and modernization of heating mains is a complex and often non-trivial task. When carrying out this activity, it is necessary to take into account many factors, such as the features of a particular infrastructure and the specifics of the operating modes of the heating network. All this places high demands on the engineering and technical personnel who carry out this process. Unreasonable and illiterate decisions can lead to accidents, which usually occur during periods of the greatest load on the heating network - during the winter heating season.
To maintain heat pipelines in working condition, many measures can be taken: from their insulation and elimination of the influence of negative external influences, to flushing the heating system from accumulated dirt. If the measures are performed correctly, then their result immediately begins to be felt in the homes and offices of consumers in the form of an increase in the temperature of the radiators of the heating system.
Carrying out repair, modernization and operational measures on heating networks is a necessary activity on the part of operating organizations and owners of heating networks. If they are carried out on time and performed efficiently, this can significantly extend the life of the heating system, as well as significantly reduce the number of accidents.
Specialists of the group of companies "Invensis" have the necessary competencies and extensive experience in the "revitalization" of heat supply networks. We will help to revive your heating networks and reduce the cost of heating and infrastructure maintenance. Our specialists are ready to conduct an audit of heating networks, develop a list of necessary repair and restoration measures, carry them out, carry out design and construction and installation work, as well as work on commissioning of equipment, and carry out maintenance.
When implementing projects for the construction, modernization and maintenance of heating networks, the Invensys group of companies pays special attention to the quality of the work performed, meeting the wishes of customers and obtaining a positive final result.
Incited by the decisions of the last congress of the Central Committee of the CPSU, the Soviet people accepted with joy and enthusiasm the decision of the Supreme Soviet of the USSR on the next scam of the lumpenized proletariat and the elimination of pensioners and the disabled as an estate, at a rate of at least 10% per year. (Stormy applause)
In our society, comrades, a vicious practice has developed - to live to retirement age without money. But it's not so scary, it's much scarier that pensioners, disabled people and veterans have the audacity to survive. And the reason for this is benefits. As a way out of this situation, it is necessary to introduce monetization everywhere, which would not allow pensioners to increase in number. (Applause, turning into an ovation.)
Approximately such a speech is heard for himself by everyone who is out of work. And no matter how rosy the media statements are, everyone understands that something is not right here. It is impossible to solve such a complex problem with such a primitive one-move as monetization. It's like checkmate in one move in chess. And if you try to analyze the consequences, then there will be no time for rainbows at all. It would be naive to believe that a crowd of economists, who know how to steal millions offshore without consequences for themselves, could not come up with anything better than a direct distribution of money. And here doubts begin to creep in that some uncle really cares about your welfare. In order to understand what awaits us, it is not at all necessary to be a seer, it is enough just to have a memory. Remember what the heating of your apartment was like twenty years ago and compare it with today. Remember what part of the salary of 100 r. you fell off then and how much you pay now, earning your 100 USD Anticipating objections about subsidies, I will say right away - nonsense. Rent in Soviet period subsidized only in hostels, warriors, large families and veterans. The rest paid for the most I don’t want, from 20 to 40 rubles. for a family of 4 people in a three-room Khrushchev without hot water (bucks then cost 48-65 kopecks, a ton of coal - 9-12 rubles). But be that as it may, now life has become better, now life is more fun. If you don't believe me, turn on the TV. It is enough to touch the radiators, look at the thermometer in your apartment, or just take off your felt boots to feel the beauty of the cool and refreshing breath of a new life. This is not the stinking warmth of past, stagnant times.
The bulk of the population generally prefers, without further ado, to plug in an electric heater and not create problems for themselves or the stokers. But for this you need a heater and money. Few of the stokers dare to raise the temperature in the boiler above 70-75C. And they can be understood too. Iron it is iron and does not like extreme sports. Few dare to risk stopping the stoker in the middle of the winter for repairs, although the passport data of any water boiler allows you to accelerate the temperature up to 100C. Limit 120C at a pressure of 0.7 atm.
Therefore, we have what we have. You can also do strikes, but the temperature of the water supply to your house will not be higher than 70C, and therefore there will be no heat in your apartment either.
Meanwhile, there is a way to “force” the batteries to heat your home and increase their efficiency by two or three times.
The method is simple and not so hot what laborious. It is necessary to install the fan so that it blows along the battery. Even an ordinary fan from the computer's power supply is enough to make the temperature in the room 3-5C higher than usual. This is the same as if you connected an additional 1 kW electric heater, or added a dozen more sections to your standard 6-8 section battery.
To do this, we bend out a U-shaped plate from the tin and bend the edges so that the plate is firmly held by the ribs of the battery. In the middle of the plate we cut out a hole for air and punch 4 small holes for mounting the fan. We fix the fan with 4 screws. The fan from the computer is designed for 12 V power supply direct current. So a power supply from an old tape recorder, a battery charger is suitable, but you can also make a self-made one, with voltage regulation. Then it will be possible to regulate both the fan speed and the noise that comes from it. We cling this structure to the battery, as close to the floor as possible, connect it and wait ... spring))). The cost of this hyperboloid, together with a self-made power supply, is comparable to the cost of 100 kWh of electricity. Power consumption does not exceed 4 watts. If the power supply is with output voltage control, then by adjusting the fan speed, you can control the temperature in the room.
The most important thing is that by using such a lotion to your battery, you reduce the dependence of the temperature in your room on the mood of the stoker.
For those who decide to do business on this, I would advise you to make a circuit that automatically turns off the fan when the air temperature in the room is higher than the temperature of the battery. This is in case the boiler is stopped in the stoker for cleaning.
In the summer, the same unit can be used as an ersatz air conditioner. And one more plus: since the rate of decay (rusting) of main pipes directly depends on the temperature of the water, in this way it is possible, by lowering the water temperature to acceptable limits, to extend the life of pipelines and boilers.
About business, about savings and possible income from this, think out for yourself ...
If we consider a residential building as an energy-consuming object, then the share of heat losses in it is winter period is: through non-insulated or broken windows and doors of entrances - 24, through walls - 26, through the basement, ceilings, stairwells -11, through ventilation openings and chimneys -39% 2.
Heat loss occurs not only through the walls of the building. They can take place during accidents on highways and at heating units of residential buildings.
A large amount of thermal energy is wasted due to poor-quality construction: cracks at window frames, joints between panels, roofs, etc., as well as in houses with inserted heating devices in the walls (30% more than with conventional heating devices). Up to 15-20% of thermal energy is lost in heating networks, which is evidenced by green grass growing in winter over heating mains.
This situation with the use of heat in everyday life was a consequence of the concept that existed in our former great country that minerals, including fuel and energy resources, in our country would be enough not only for the current, but also for future generations. And when designing residential buildings, the cost of their operation was never considered, which is why they built relatively cheap, but cold houses.
Approximately 65% of heat energy is spent for household needs in the Republic of Belarus. At the same time, heat loss in the production and transmission of thermal energy in heating boiler houses of the republic reaches 30%. For 1 m 2 of heated area in our country, 2 times more conventional fuel is spent than in Germany and Denmark.
The annual consumption of thermal energy in our country for heating and ventilation of 1 m 2 of the total area in a 5-storey building is 150-170 kW, in the Scandinavian countries - 70-90 W. In the West, after the energy crisis of 1972-1973 and 1995, the advanced European countries reduced the consumption of thermal energy for heating residential buildings by 2 times. And it's not just savings. Money but also, most importantly, a change in the very thinking of citizens and leaders.
According to sanitary standards 3, hot water must be supplied to apartments at least 50 °C, but it is supplied at a temperature of 37 ... 38 °C. The air temperature in the apartment should be maintained at 18 ... 20 ° C (comfort zone), and in kitchens 4 - 16 ... 18 ° C. The family pays only 16-17% of the total cost of heating the house, and only 20% of the cost of heat and electricity generated. With such an existing system of payment for the consumed heat and electricity, it will be difficult to achieve a radical change in the improvement of the domestic sector until the tenants have an economic interest in saving heat energy. And for this we have to change the psychology of all citizens in relation to saving heat, water, gas. The entire European experience shows that only a well-thought-out continuous system of upbringing and education allows you to get real results in energy saving in the domestic sector and the production sector. In the West, in particular in Germany, 78% of all housing receives heat from local boilers, the unit cost of which is 0.05 DM / kWh, while with district heating it is: the figure is 0.08. The experience of decentralized heat supply available in our country shows its high efficiency. Local boiler houses built in the capital (Belarus hotel, several residential buildings, etc.) pay for themselves in 1.5-3 years 5 . In 1998, 77 million Gcal were produced to meet the needs of the country, in 1999 - 70 million Gcal of thermal energy. In order to meet the needs of the republic, 50 million Gcal is enough per year.
Giving importance energy saving in the housing and communal sector of the economy, on June 13, 2001, the President of the Republic of Belarus A.G. Lukashenko instructed the regional executive committees and the Minsk City Executive Committee, together with the interested ministries and departments, to implement measures to improve the efficiency of housing construction, reduce costs for the development of engineering, transport and social infrastructures due to the compaction of buildings, the use of local sources of heat energy, autonomous heating systems, water supply and sewerage.
One of technical solutions reducing the heat supply network and saving heat energy is decentralized heat generation with the help of automated autonomous, including roof-top, boiler houses (running on gas fuel. The advantage of this type of heat supply is as follows: the ability to build a boiler room that satisfies the needs of this particular building; saving land; saving energy due to the absence of losses; the ability to control heat and fuel; setting the required mode of heat consumption depending on the length of the working day and outdoor temperature; high efficiency (90%) of boiler plants; lower temperatures and coolant pressures, which increases the durability of heating systems.
Heating systems of residential and public buildings are among the most significant consumers of thermal energy. The consumption of thermal energy for these purposes is more than 30% of the energy resources consumed by the national economy. Wherein apartment buildings, built in 1950-1960, spend from 350 to 600 kWh per 1 m 2 for heating needs. For comparison, we point out that this figure is 260 kWh in Germany, and 135 kWh 3 in Sweden and Finland.
The most promising areas of energy saving are the introduction of autonomous heat and power supply systems, underfloor heating, as well as installations using renewable energy sources and heat recovery units.
Autonomous heating systems in the form of mini-boilers are becoming promising V where natural gas is used as fuel. From an environmental point of view, they also contribute to improving the condition of the air basin, because due to a decrease in the amount of gas burned, the amount of flue gases decreases, and gas emissions contain 2-3 times less harmful substances in 1 m 3 than large regional boiler houses. But decentralized heat supply based on small individual boiler houses is effective at low heat load density (one-, two-story buildings in rural and other settlements).
Naturally, with the existing developed district heating networks, it is unreasonable to talk about a widespread transition to autonomous boiler houses. But their implementation is possible in the following cases:
During the construction of new and reconstruction of old buildings in areas where the laying of heating networks is technically impossible;
To provide heat to facilities that do not allow fluctuations in heat supply (schools, hospitals), or consumers who suffer large economic losses due to lack of heat (hotels);
When providing heat to consumers located at the end sections of existing heating networks and experiencing a lack of heat due to the low throughput of heating networks or insufficient! pressure difference between the direct and return lines;
During the construction of facilities in small towns, where district heating is poorly developed, and individual facilities are introduced separately.
The main element of an autonomous power plant is combined gas wall-mounted water heaters, in the body of which there is a silent circulation pump and a membrane expander. Hot water from the water heater metal pipes, fit into concrete preparation floor or in a plinth of a special design, divorced from room to room.
Operating experience of a 72-apartment nine-story residential building in microdistrict No. 17g. Gomel with this fundamentally new heat supply system for our country, developed by the Gomelgrazhdanproekt Institute, showed its reliability and efficiency. So, in November 1999, a family of 4 living in a three-room apartment consumed 150 m 3 of gas for heating, hot water supply and cooking; about 500 m 3 of gas would be required from a common house system with connection to an external source for heating and hot water supply.
The high efficiency of the proposed system of apartment heating is achieved due to:
Relatively high efficiency gas water heaters(“85%);
Exclusion of heat losses outside the apartments;
Absence of excess heat consumption during off-season periods (according to available data, it is up to 20%);
Possibilities of apartment-by-apartment accounting and room-by-room temperature control inside the apartment.
In addition, the system of apartment heating and hot water supply has significantly reduced the number of metering devices. Instead of currently used meters for gas, heating, hot and cold water supply, it is enough to install only two devices for metering gas consumption and cold water. In addition, there is no need for laying external heating networks. Perhaps one of the most important advantages of this heating system over the traditional one is that it allows the owner of the apartment to create a comfortable air temperature not by opening the window and window sash, but by using a manual control valve or an automatic thermostatic head, thereby saving their money for apartment heating and state energy resources.
Saving heat consumption due to the above advantages of apartment heating reaches 30% per year.
The construction of residential buildings with such a system of engineering support is highly justified in areas of existing urban development, where there are no reserve capacities of existing centralized heat supply sources.
The experience of autonomous boiler houses shows that they are reliable and economical. When heat is supplied from these boiler houses, the consumer receives thermal energy at tariffs that are 3 times lower than the current ones. Due to this, the construction of such boiler houses pays off in almost one season.
In all industrialized and energy developed countries, there is a very rapid growth in the use of electric heating, usually carried out by laying heating cables in the floor. The use of electric heating is allowed by SNIP 2.04.05-91. For rooms with permanent residence of people, it is established that the average temperature of the heated floor should not exceed 26°C, and for the paths around the pools - no more than 30°C. One of such electric heating systems is the Teplolux cable system. It is installed in the thickness of the floor, which turns the entire heated surface into a heat source, the temperature of which is only a few degrees higher than the air temperature. This system, like others like it, is used as the main one in detached buildings, cottages and in cases where it is not possible to connect central water heating. It can be used as an additional heating system (together with others) to obtain room temperature.
Absolutely new way heating of premises for various purposes was developed at BITU by Professor V.P. Lysov. The polymeric heating wiring he created, consisting of hundreds of the thinnest polymer fibers processed according to the original technology with a special solution and connected into a bundle, provides, at the same power consumption, a much higher temperature increase than that of a metal conductor, since the fibers constantly heat each other. This wiring, or rather, a set of wires, is laid out according to the scheme for prepared concrete base and cement. You can also place wires under tiles, various linoleums, carpets, under boardwalk and parquet. In any case, the doctor-recommended floor temperature of 25 °C and air temperature of 20...22 °C will be provided. For reliability, you can turn on the network and an automatic thermostat.
The cost of heating and operation in this way is 1.5-2 times lower compared to others known ways, including similar foreign heating floor systems, where metal conductors are used. But the lack of metal conductors is the eddy currents that accompany it, which are undesirable for the body. The polymer conductor generates an electromagnetic field 2-10 times weaker, which does not even come close to the lower limit.
The scope of this heating method is very wide: houses, apartments, offices, livestock buildings, etc. Its advantages are appreciated by many owners of their own houses, managers, but the heads of state farms are especially pleased, where the novelty has been used for 3 years and, in addition to saving energy for heating, in greatly contributes to the preservation of livestock and their weight gain. According to the research conducted by the scientists of the BelNII of Animal Husbandry in places where animals are kept with heated floors, it was found that the safety and weight gain of piglets increase, while the power consumption is reduced from 250 W with lamp heating to 120-130 W with heated floors per 1 livestock place. This method of heated floors has been introduced in many farms of the country.
The ease of installation and operation of heating floors, low cost and energy consumption in comparison with traditional heating technologies were appreciated by the owners of more than 1.5 thousand apartments and private houses, cottages and garages, offices and shops of the republic, increasing their living and working comfort. To this it should be added that the cost of arranging heating is 10-12 US dollars and is offset by the savings achieved for 5-6 months of operation in the cold season.
To provide public, residential and industrial premises with cheap heat using local fuels, it is economically beneficial to use air heating based on heat generators.
