Improving the efficiency of heating systems. Apartment ventilation system with heat exchangers. 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 using 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 through partial reconstruction of heating systems.
There are several different ways to improve the efficiency of heating systems in residential buildings, differing both in the volume of costs for their implementation and in the limitations of their use.
The most conservative way of energy saving for the heat supply from the central heating station is to install individual thermostatic regulators in houses on heating devices. Studies show that the introduction of integrated automation can reduce the heat consumption of the house as a whole (in comparison with the elevator unit) by 15–20%. Foreign experience shows that individual heat metering in combination with the ability to regulate heat consumption results in heat savings of up to 25%. This scheme is being implemented today in apartment heating systems, for example, in experimental projects.
On the other hand, developers and builders of new residential buildings increasingly come 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 district heating systems has deteriorated significantly almost everywhere due to chronic underfunding and equipment wear. Therefore, accidents, stoppages and banal deception of the consumer are frequent, when the pressure and temperature in heating plants are deliberately lowered, and the consumer does not receive heat, regularly paying for it. Such negative aspects are kept to a minimum 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 consumption occurs in the immediate vicinity of the place of its production, that is, in general, decentralized systems have a much higher efficiency than central heating systems.
Electric heating has recently become another alternative to traditional central heating. , which was not widely used in Russia before 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 changing rapidly due to the steady rise in the price of all energy carriers. Moreover, the potential for price growth to the world level is the highest for gas, and the lowest 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 central heating systems, and this advantage will only grow over 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 half a year 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 an active bright sun, the power of the tube showed about 130-150W, but ...
Closed geothermal systems providing only hot water supply. Depending on the location of the discharge point and the source of drinking water, three types of circuit design can be used. Scheme (Fig. 2.6.). Geothermal water is supplied ...
Thermal efficiency of the heating device in the room and the choice of the installed thermal power 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 waste of heat. The indicator that evaluates 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 in the room.
It is believed that radiant panels installed in the upper area of \u200b\u200bthe room or built into the ceiling structure have the best heating effect. The heating effect of such devices is 0.9-0.95, that is, the heat transfer of ceiling radiator panels can be even slightly lower than the calculated heat loss of the room without deteriorating 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 an external wall. The surface of the device overheats and through this part outer wall some heat is wasted unnecessarily. As a result, the heating effect of radiators is estimated at 1.04-1.06. In this respect, convectors located along the outer wall are more effective. Heating effect, for example of a skirting convector about 1.03.
A window sill panel built into an external wall structure can have a noticeable waste of heat and its heating effect is reduced to 1.1.
Heating devices usually have a certain step of the adopted nomenclature series, 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 related increase in the heat flux from the 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 of an individual element of the device from 0.12 to 0.3 kW.
Additional heat losses by the heating device installed at the outer fence are taken into account by the coefficient β 2. Its value, depending on the type of device and the method of its installation at the external 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 by pipes built into the structure of external fences, as well as in the heating point and other elements of the system. Additional heat losses Q tr pipes in unheated rooms associated with the cooling of the heat carrier are also determined.
The value of the total additional losses (outside the device sections of external fences and heat pipelines in unheated rooms) should be, according to SNiP, no more than 7% of the thermal power of the heating system.
Specific thermal characteristic of the building and calculation of heat demand for heating using enlarged meters
For the thermal engineering assessment of space-planning and structural solutions and for an approximate calculation of the heat loss of a building, an indicator is used - the specific thermal characteristic of the building q, which, for known heat losses of the building, is equal to:
q \u003d Q bld ∕
where Q bld is the estimated heat loss through the external fences by all rooms of the building, W; V - the volume of the heated building by external measurement, m 3, (t in - t n) - the calculated temperature difference for the main premises of the building.
The q value, 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 \u003d 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 ° C; 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. The indicators of efficiency are the manufacturability of the design, the mass of the elements, labor costs and terms of manufacture and installation, the costs of adjustment, management and repair.
The manufacturability of the design includes such real measures as simplification of the circuit, unification and reduction of the number of parts, the use of normals, ease of assembly, which ensure the manufacture and installation with minimal cost time, money and labor.
The economic effect is revealed when conducting a technical and economic comparison of various design solutions. The comparison allows you to choose the most economical heating system in the given specific conditions.
In an economic comparison of options, the following indicators are used: capital investments K, operating costs I, duration of installation work and operation of the heating system. Some of these indicators are usually used. The simplest is to compare heating systems with various devices, but with one type of coolant and with one scheme, since it is done only for capital investments. The systems are most often compared in terms of capital investment and operating costs. Less often, they also take into account the terms of installation and service of systems, the presence of labor reserves.
The most economical option is that with the minimum total capital investment and operating costs. You usually have to compare two options, one with lower capital investment, the other with lower operating costs. So, with a decrease in the diameter of the pipes of a pumping water heating system, capital investments decrease, but electricity consumption increases; system automation increases capital investment but reduces operating costs. An economically more effective option is identified in such cases, depending on the term z, years, payback of additional capital investments.
Z \u003d (K 1 - K 2) ∕ (And 1 - And 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 of I 2 during the year is advisable. The normative period z n payback on investments in the heating system is taken equal to 8.33 years (12.5 years for new technology and energy-saving measures), regardless of the type of building.
In an economic comparison of several systems or system variants for each of them, the reduced costs are found
3 \u003d (K ∕ z n) + I,
and, the option that has the lowest reduced costs for the standard payback period is considered more efficient.
Capital investments in the heating system are made, as a rule, within one year. Operating costs change annually; in addition, they depend on the service life of both the system and its individual elements.
Annual operating costs consist of direct heating maintenance costs and depreciation costs
And \u003d And pr + A
where And pr - direct operating costs, consisting of the annual costs of the received thermal energy (fuel), electricity, wages of maintenance personnel, system management and maintenance; A - amortization costs, including annual costs overhaul systems and deductions for the full restoration of capital investments.
Deductions for the restoration of capital investments are associated with the standard service life of the system, determined based on the terms of physical wear and tear of its elements: radiators (40 years), water pipes (30 years), steam pipelines, centrifugal pumps, valves (10 years), fans, air heaters, heating units (8 years), filters (6 years), condensate lines (4 years).
The service life is determined not only by physical, but also by the obsolescence of the heating system, and obsolescence is considered the loss of the ability to maintain the temperature in all serviced rooms at the required level. The standard service life of common water heating systems is currently taken equal to 30 - 35 years (shorter period for convectors).
When matching different systems heating systems comply with equal or at least similar performance indicators for all options: the systems must ensure the fulfillment of sanitary and hygienic, fire-prevention and anti-explosion requirements, and must also have equal efficiency.
The service life of hot water heating systems, as we already know, is the longest. Due to the decrease in depreciation costs, while saving electrical and heat energy, the operating cost is reduced, 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 generated in rooms with compared heating systems is taken into account by the change in the service life and the degree of space utilization. For a system that provides more comfortable conditions, the design service life is increased by 5-10 years (taking into account less obsolescence). In addition, the use of the working area of \u200b\u200bthe premises in the cold season (by changing the size of the discomfort zone) is taken into account, adding part of the cost of construction work on the discounted area to the estimated cost of another system.
Nevertheless, the main indicator of the efficiency of a heating system is the heat consumption during its operation. It is known that only annual operating costs exceed half the cost of a system device. And the main part of the costs falls on the payment of consumed heat. Heat consumption for heating with a steam or central air system exceeds the heat consumption in the water heating system due to an increase in associated heat losses through the walls of steam pipelines and air ducts, which are useless for heating working rooms.
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 (water, air). Due to the widespread use of centralized water heating in our country, most central heating systems have actually become combined - water-to-water or water-to-air.
At present, combined heating has come to be understood as a combination of two operating modes of a system or two systems for heating the same room with a variable thermal regime. Improvement of the work and arrangement of heating systems is also being carried out to improve the thermal regime of premises and reduce heat consumption for heating buildings. A constructively similar solution was encountered earlier, when two heating systems of different capacities were provided for heating a periodically used industrial premises: one for the working period, the other (on duty) for non-working.
Distinguish between combined heating two-mode, two-component, with intermittent mode.
Dual mode is called heating operating at different temperatures of the same coolant at different times of the day. A two-mode system is a hot water heating system in which water circulates during the working period at low temperature (for the useful use of internal heat release), and in the non-working period - with increased (or vice versa). To lower the temperature, a mixing pump is turned on; to increase, a direct-flow coolant supply from an external heat pipe is used without mixing chilled water.
The air heating system combined with supply ventilation during the working period, and recirculating 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 ensure the necessary heat supply to the premises. The first system, usually hot water heating, called background or baseline, is arranged with a reduced power (for example, 30% of the calculated heat demand of common rooms) for constant unregulated operation throughout the entire heating season. The task of this system is to equalize the heat deficit per unit area or volume of ordinary and corner, lower and upper rooms of the same type (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. The action of the heating system is automated to operate according to a given program.
Combined heating can operate intermittently, and then the thermal regime of the premises is characterized by three states: constancy of temperature during working hours, free temperature drop when the heating system is turned off, and heating of premises before starting work or in holidays (about intermittent heating). Various combinations are also possible the listed types combined heating, when two-mode operation of one or both two-component heating systems is provided.
Improving the efficiency of building heating
The 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 building's SCM. The engineering techniques discussed in this section are aimed at this.
The complex property of an SCM building to effectively perform its functions is usually a probabilistic characteristic. The efficiency of a 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 assemblies and elements during operation within the estimated terms and conditions.
Controllability - probabilistic maintenance of the specified deviations in the operation of individual parts and zones of the heating system during control and during operation during the heating season.
Security - accepted in the project keeping with the admissible probability of deviations of the calculated 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 to maintain the design temperature of the premises.
Distinguish between starting and operational regulation of the system. These types of regulation have their own characteristics for water, air and steam heating systems.
When the heating system of a group of buildings is started up, connected to the heat pipelines of the district heating supply, the distribution of the coolant among the individual buildings is provided 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 with independent connection of the heating system to heat pipelines, are considered in the discipline "Heat supply".
Start-up regulation of elements and units of the heating system is associated with the provision in them of the design flow rate of the coolant.
Operational regulation of the heating system is carried out in order to ensure heat supply to the heated rooms corresponding to the current heat demand. The control methods also differ depending on the heat carrier used in the system. Depending on the location of the regulation in the heat supply system, there are central, group, local and individual regulation.
In a water heat supply system, central regulation is carried out at a thermal station (CHP, boiler house) according to the so-called heating schedule, which establishes a relationship between the parameters of the coolant (temperature at qualitative or flow rate at quantitative regulation) and the outside air temperature as the main factor determining the variable nature of the components of the heat balance buildings during the heating season
Central regulation at a thermal station for heat supply of 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 the stable operation of heating systems.
The stability of work increases when 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. So, with group control in the central heating station, it becomes possible to distribute heat according to specified temperature schedules, which contributes to an increase in the heating efficiency of each building. With local regulation at the heating point of a building, the peculiarities of the mode of its operation, orientation along the sides of the horizon, the effect of wind and solar radiation are taken into account.
Improving the efficiency of heating 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 the heating network.
Traditionally, insufficient attention is paid to them, and a low level of culture of exploitation, 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 happen on them, this leads to refusals in heat supply to end users.
It is widely believed among non-specialists that the operation of heating networks is a simple and unsophisticated occupation. This approach results in a lack of focus on operational issues. Therefore, the state of heating networks, as an element of the entire heat supply infrastructure, is in a very depressing 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, to intensively consume fuel, which is why the costs rise disproportionately.
It often happens that as the production expands or the settlement grows, the existing heating network ceases to meet the necessary needs. Sometimes, when examining networks, design errors and implementation flaws are revealed construction works... In heat 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 systems are in such a worn-out state that the modernization of boiler houses and heating points does not give the desired effect. However, in such cases, just by increasing the efficiency of heating networks, it is possible to significantly increase the quality of heat supply and reduce operating costs.
Technologies for the construction and operation of heating mains do not stand still. New types of pipes, fittings appear, new heat-insulating materials are 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 specifics of a specific infrastructure and the specifics of the heating network operating modes. All this places high demands on the engineering and technical personnel carrying out this process. Unreasonable and illiterate decisions can lead to accidents, which usually occur during periods of greatest load on the heating network - during the winter heating season.
To maintain the heat pipelines in working order, many measures can be taken: from their insulation and elimination of the influence of negative external influences, to flushing the thermal 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 are carried out efficiently, this can significantly extend the service life of the heating network, as well as significantly reduce the number of emergencies.
Specialists of the Invensys group of companies have the necessary competencies and extensive experience in “revitalizing” heat supply networks. We will help you revive your heating networks and reduce heating costs and infrastructure maintenance. Our specialists are ready to audit heating networks, develop a list of necessary repair and restoration measures, carry out them, carry out design and construction and installation work, as well as commissioning of equipment, and carry out maintenance.
When implementing projects for the construction, modernization and maintenance of heating networks, the Invensis group of companies pays special attention to the quality of the work performed, meeting the wishes of customers and obtaining a positive final result.
Encouraged by the decisions of the last congress of the Central Committee of the CPSU, the Soviet people joyfully and enthusiastically embraced the decision of the Supreme Soviet of the USSR on the next kidnyak of the lumpenized proletariat and the elimination of pensioners and invalids 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 up to retirement age without money. But it’s not so scary, much more scary 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 everywhere monetization, which would not allow pensioners to increase in their number. (Applause turning into a standing ovation).
Anyone who is out of work hears something like this. And no matter how rosy the statements of the media may be, everyone understands that something is wrong here. It is impossible to solve such a complex problem with such a primitive one-move move as monetization. This is the same as in chess to checkmate in one move. And if you try to analyze the consequences, then there will be no time for rainbows. It would be naive to believe that a crowd of economists who know how to snatch millions offshore without consequences for themselves could not think of 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 visionary, it is enough just to have a memory. Recall how your apartment was heated twenty years ago and compare it with today. Remember how much of a salary of 100 rubles. you dropped off then and how much you pay now, earning your $ 100. Anticipating objections to subsidies, I will say right away - nonsense. The rent in the Soviet period was 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 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 simply take off your felt boots to feel the beauty of the cool and refreshing breath of 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 for the stokers. But this requires a heater and money. Few of the stoker's brethren dare to raise the temperature in the boiler above 70-75C. And they can be understood too. Iron is iron and does not like extremes. Few dare to risk stopping the stoker in the middle of 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 make strikes, but the temperature of the water supplied 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, three times.
The method is simple and not very laborious. It is necessary to install the fan so that it blows along the battery. Even a regular fan from the computer's power supply is enough to keep the room temperature 3-5C higher than usual. This is equivalent to connecting an additional 1 kW electric heater, or adding a dozen more sections to your standard 6-8 section battery.
To do this, we bend a U-shaped plate out of the tin and bend the edges so that the plate is firmly held by the edges of the battery. Cut out an air hole in the middle of the plate and punch 4 small holes for the fan mount. We fix the fan with 4 screws. The fan from the computer is designed for 12 V power direct current... So a power supply from an old tape recorder, a battery charger, will do, but you can also blind 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 attach this structure to the battery, as close to the floor as possible, connect and wait ... for spring))). The cost of this hyperboloid together with a self-made power supply is comparable to the cost of 100 kW / h of electricity. Power consumption does not exceed 4 watts. If the power supply unit will be with output voltage regulation, then by adjusting the fan speed, you can adjust the room temperature.
The most important thing is that by using such a lotion for 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 to make a circuit that automatically turns off the fan in the event that the air temperature in the room is higher than the battery temperature. This is in case the boiler is stopped in the stoker for cleaning.
In the summertime, this 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 service life of pipelines and boilers.
You can think of business, savings and possible income from this ...
If we consider a residential building as an energy-consuming object, then the share of heat loss in it is winter period makes up: through non-insulated or broken windows and doors of entrances - 24, through walls - 26, through the basement, ceilings, staircases -11, through ventilation holes and chimneys -39% 2.
Heat loss occurs not only through the walls of the building. They can occur during accidents on highways and at heating units of residential buildings.
A large amount of heat energy is lost due to poor-quality construction: the cracks at window frames, joints between panels, roofs, etc., as well as in houses with installed heating devices in the walls (30% more than with conventional heating devices). Up to 15-20% of thermal energy is lost in heating networks, as evidenced by the green grass growing in winter above 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 there will be enough minerals, including fuel and energy resources in our country, not only for the present, but also for future generations. And when designing residential buildings, the cost of their operation was never considered, and therefore relatively cheap but cold houses were built.
Household needs in the Republic of Belarus consume about 65% of thermal energy. At the same time, heat loss during the production and transmission of heat energy in heating boiler houses of the republic reaches 30%. For 1 m2 of heated area in our country, 2 times more equivalent fuel is spent than in Germany and Denmark.
The annual consumption of heat 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 this is not only savings money, but also, most importantly, a change in the very thinking of citizens and leaders.
According to sanitary standards 3, hot water should be supplied to apartments at least 50 ° С, but it is supplied at a temperature of 37 ... 38 ° С. The air temperature in the apartment should be maintained at 18 ... 20 ° С (comfort zone), and in kitchens 4 - 16 ... 18 ° С. The family pays only 16-17% of the total cost of heating the house, and only 20% of the cost of generated heat and electricity. With such an existing system of payment for consumed heat and electricity, it will be difficult to achieve a radical change in improving the situation in the domestic sector until the residents are economically interested in saving heat energy. And for this it is necessary to break the psychology of all citizens in relation to saving heat, water and gas. All 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 household sector and production area... In the West, in particular in Germany, 78% of all housing receives heat from local boiler houses, the unit cost of which is 0.05 DM / kWh, while with district heating this is: the indicator is 0.08. The experience of decentralized heat supply available in our country shows its high efficiency. Local boiler houses built in the capital (hotel "Belarus", several residential buildings, etc.) pay for themselves in 1.5-3 years 5. In 1998, 77 million Gcal of heat were produced to meet the country's needs, 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 essential energy saving in the housing and communal sector of the economy, the President of the Republic of Belarus A.G. Lukashenko instructed the regional executive committees and the Minsk city executive committee, together with interested ministries and departments, to carry out measures to increase the efficiency of housing construction, reduce the cost of developing engineering, transport and social infrastructures due to the compaction of buildings, the use of local heat sources, autonomous heating systems, water supply and sewerage. "
One of technical solutions reducing the heat supply network and saving heat energy is a decentralized heat generation by means of automated autonomous, including roof, boiler houses (fueled with gas fuel. The advantage of this type of heat supply is the following: the ability to build a boiler house that meets 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 the outside temperature; high efficiency (90%) of boiler plants; lower temperatures and pressures of the coolant, which increases the durability of heat supply systems.
Heating systems for residential and public buildings are among the most significant consumers of thermal energy. Heat consumption for these purposes is more than 30% of the energy resources consumed by the national economy. Wherein apartment buildings, built in 1950-1960 years spend for heating needs from 350 to 600 kW * h per 1 m 2. For comparison, we point out that this figure is 260 kWh in Germany, and 135 kWh in Sweden and Finland 3.
The most promising areas of energy conservation 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 heat supply systems in the form of mini-boiler houses are becoming promising inplaces where natural gas is used as fuel. From an environmental point of view, they also contribute to an improvement in the state of the air basin, since due to a decrease in the amount of burnt gas, the amount of flue gases decreases, and gas emissions contain 2-3 times less harmful substances in 1 m 3 than large district boiler houses. But decentralized heat supply based on small individual boiler houses is effective at a low heat load density (one-, two-story buildings in rural and other settlements).
Naturally, given the existing well-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 objects that do not allow drops in heat supply (schools, hospitals), or consumers that 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 low throughput of heating networks or insufficient! pressure drop between the direct and return lines;
When constructing facilities in small towns, where district heating is poorly developed, and individual facilities are introduced separately.
The main element of the autonomous power plant is the combined gas wall water heaters, in the case of which there is a silent circulation pump and a membrane expander. Hot water from the water heater to metal pipesstacked in concrete preparation floor or in a skirting board of a special design, divorced from room to room.
Operating experience of a 72-apartment nine-storey residential building in microdistrict No. 17g. Gomel with this fundamentally new for our country heat supply system, developed by the Institute "Gomelgrazhdanproekt", has shown its reliability and efficiency. So, in November 1999, a family of 4 people living in a three-room apartment consumed 150 m 3 of gas for heating, hot water supply and cooking ;: Moreover, a third of this amount was consumed directly in the kitchen.The performed calculations showed that with a traditional heating system for a similar apartment from a common building system connected to an external source for heating and hot water supply, about 500 m 3 of gas would be required.
High efficiency of the proposed apartment heating system is achieved due to:
Relatively high efficiency gas water heaters (“85%);
Elimination of heat loss outside the apartments;
The absence of excessive consumption of heat in off-season periods (according to available data, it is up to 20%);
Possibilities of apartment accounting and room-by-room temperature control inside the apartment.
In addition, the apartment heating and hot water supply system has significantly reduced the number of metering devices. Instead of the currently used gas meters, heating, hot and cold water supply, it is enough to install only two devices to measure the gas consumption and cold water... In addition, there is no need to lay 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 leaf and window sash, but using a manually controlled adjusting valve or an automatic thermostatic head, thereby saving own money for heating the apartment 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 the existing centralized heat supply sources.
The experience of autonomous boiler houses shows that they are reliable and economical. With heat supply from these boiler houses, the consumer receives heat 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 industrial and energy developed countries, there is a very rapid increase 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 premises with a constant stay of people, it has been established that the average temperature of the heated floor should not exceed 26 ° С, and for paths around the pools - not more than 30 ° С. One of such electric heating systems is the Teplolux cable system. It is installed in 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 (in conjunction 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 polymer heating electrical wiring created by him, consisting of hundreds of the finest polymer fibers processed according to the original technology with a special solution and connected in a bundle, provides, with the same power consumption, a temperature rise that is much higher 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 cemented. You can also place wires under tiles, various linoleums, carpets, under boarding and parquet floors. In any case, the floor temperature recommended by doctors will be provided at 25 ° C, and at 20 ... 22 ° C. For reliability, you can include an automatic thermostat in the network.
The cost of heating and operation in this way is 1.5-2 times lower compared to others known methods, including similar foreign heating floor systems, where metal conductors are used. But the disadvantage of metal conductors is the eddy currents that accompany it, undesirable for the body. The polymer conductor generates an electromagnetic field 2-10 times weaker, which does not 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 satisfied, where the novelty has been used for 3 years and, in addition to saving energy resources for heating, contributes to the preservation of livestock and their weight gain. According to the research conducted by the scientists of the BelNII Livestock Research Institute of animal husbandry with heated floors, it was found that the safety and weight gain of piglets increases, 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 in the country.
The simplicity of the installation and operation of heating floors, the low cost and consumption of electricity in comparison with traditional heating technologies were appreciated by the owners of more than 1.5 thousand apartments and private houses, summer cottages and garages, offices and shops in the republic, increasing their comfort in living and working. To this it should be added that the costs of arranging heating are 10-12 US dollars and are compensated 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 profitable to use air heating based on heat generators.
