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Upper springs are built at the ends of the heating systems, and a third large boiler goes into operation. Other customers' communications were exhausted by capacity reserves, and the system required the continuation of the construction of the second phase, in accordance with the original intentions. A subsequent in-depth review of heat management in the Liberian metropolitan area resulted in a number of measures, as well as a decision to terminate the centralized resource. Powerful mobile sources were deployed at the ends of the system, and some previously shutdown boiler houses were returned to service.

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Introduction

Heat consumption industrial enterprises makes up the majority of the total heat consumption. Every year the share of centralized heat supply of industrial enterprises from thermal power plants is growing, which makes it possible to eliminate a large number of industrial boilers and thereby reduce air pollution by emissions of combustion products.

Industrial enterprises receive steam for technological needs and hot water both for technology and for heating and ventilation. Of great importance are heating network, steam and water, through which steam and hot water to consumers. The process steam condensate return system at the CHPP is also extremely important. The production of heat for industrial enterprises requires large amounts of fuel burned in the furnaces of steam generators of combined heat and power plants and boiler houses.

For CHP and boiler houses, network districts, improving the quality of labor means achieving defect-free work. To do this, it is necessary to carry out a whole system of measures, which include advanced training, personnel training, and a system of preventive repairs.

The efficiency of production is ensured by its high technical and economic indicators, among which the most important are the specific fuel consumption for the supplied heat and electricity.

Thermal consumption is the use of thermal energy for a variety of domestic and industrial purposes (heating, ventilation, air conditioning, showers, baths, laundries, various technological heat-using installations, etc.).

When designing and operating heat supply systems, the following must be taken into account: a) type of heat carrier (water or steam); b) coolant parameters (temperature and pressure); c) maximum hourly heat consumption; d) change in heat consumption during the day (daily schedule); e) annual heat consumption; f) change in heat consumption during the year (annual schedule); g) the nature of the use of the coolant by consumers (direct intake from the heating network or only heat extraction).

Heat consumers present to the heat supply system different requirements. Despite this, heat supply must be reliable, economical and satisfy all heat consumers in a quality manner.

Heat consumers can be divided into two groups: a) seasonal consumers; b) year-round consumers.

Seasonal consumers use heat not all year round, but only during some part of it (season), while the heat consumption and its change in time depend mainly on climatic conditions (outdoor temperature, solar radiation, wind speed and direction, air humidity). The main value is the temperature of the outside air; the influence of others climatic factors heat consumption is often neglected.

Seasonal consumers of heat are: a) heating; b) ventilation (with air heating in heaters); c) air conditioning (obtaining air of a certain quality, purity, temperature and humidity).

Year-round consumers use heat throughout the year. This group includes: a) technological consumers of heat; b) hot water supply for household consumers.

If for seasonal consumers the heat consumption practically depends on one factor - the outside air temperature, then for year-round consumers - on many different factors. Thus, the technological consumption of heat depends on the production technology, the type of products produced, the type of equipment, the mode of operation of the enterprise, etc. Climatic conditions have very little effect on the heat consumption of year-round consumers.

Year-round consumers provide the most economical operation of the CHPP throughout the year, while seasonal load due to its uneven annual schedule and especially in view of the presence of a summer dip leads to a decrease in the efficiency of the CHP.

The further development of hot water supply, air conditioning and refrigeration planned in our country will not only further improve living conditions population, but will also have a positive effect on the efficiency of heat supply systems.

1. Schedule of central quality regulation

One of the main ways to control heat supply by a source of district heating is to generate heat with optimal, economically most profitable parameters (qualitative regulation of heat supply). To determine such optimal parameters coolant, a temperature graph is plotted.

The construction of the graph is based on determining the dependence of the temperature of network water in the supply and return lines on the temperature of the outside air.

Calculation of coolant temperatures in the supply and return lines of the heating network at various temperatures outdoor air is carried out according to the formulas:

where t v.r - the estimated air temperature inside the room, about C, we accept according to Appendix 3

Dt - temperature difference of the heating device, o C

where f e is the calculated temperature of the water entering the heating devices (after mixing in the elevator), o C, equal to

where a is the mixing ratio, equal to the ratio of the amount return water, mixed by the elevator to the amount of water coming from the heating network (assumed a = 1 ... 2.5)

Df - estimated water temperature difference in a warm network at an external heating temperature, o C:

Df \u003d f p? f about \u003d 140? 70 \u003d 70

and - estimated temperature difference in the local heating system, o C

i \u003d f e -f o \u003d 93.33-70 \u003d 23.33

t n.o - design outdoor air temperature for heating design, o C, determined according to Table 1.3 for Kazan, t n.o =? 29.

t? n - accepted arbitrary values ​​of outdoor air temperatures in the temperature range from t n.o to t v.r, o C

Att? n= t But= ? -29 OWITH

Further calculation is carried out similarly, setting the outdoor air temperatures t? n \u003d -12, -10, -8, ..., +8 o C. We summarize the calculation in table 1.

Table 1 - Construction of the CCR schedule

Based on the data obtained, we build a schedule of central quality regulation.

2. Determination of the calculated heat consumption

To determine the estimated heat costs, we will compile a table of characteristics of buildings that are part of an industrial enterprise for which a heat supply system is being designed.

Table 2 - Characteristics of buildings

Designation	Purpose of the building		t w.r. , o C	Specific characteristic, W / (m 3 K)	Quantity, pcs	Internal heat generation, kW	Steam consumption, t/h
				heating, q o	ventilation, q in	wash basins
	Administrative
	Dining room
	machine shop
	machine shop
	Repair shop

We determine the calculated heating load Q o, W

Q o \u003d q o V (t v.r? t n.o), (5)

where q o - specific heating characteristic buildings, W / (m 3 K);

V - construction volume of the building according to the external measurement, m 3.

t v.r - design air temperature, indoors, o C;

t n.o - outdoor air temperature for heating design, o C

Q A o. max \u003d 0.298 18750 (18 + 29) \u003d 262612.5

Q B o. max \u003d 0.45 8000 (16 + 29) \u003d 162000

Q 3 about. max \u003d 0.448 37500 (16 + 29) \u003d 756000

Q max \u003d 0.448 37500 (16 + 29) \u003d 756000

Q And about. max \u003d 0.38 50000 (18 + 29) \u003d 893000

The main task of heating is to maintain the temperature of the premises at a given level. To do this, it is necessary to maintain a balance between the heat losses of the building and the heat gain. Thus, when determining the estimated heat consumption for heating industrial buildings it is necessary to take into account the amount of internal heat generation from the process equipment of workshops, which are quite stable and often represent a significant proportion of the calculated heating load, as well as infiltration losses reaching 25-30% of heat loss through external fences. Hence,

Q? O. max =m Q o . max - Q ext, (6)

where m is the infiltration coefficient; for public buildings take m=1, for industrial buildings m=1.25…1.3;

Q ext? internal heat generation, W;

Q? And about. max=1 262612.5=262612.5

Q? b o. max=1 162000-90000=72000

Q? Z o. max=1.3 756000=982800

Q? s o. max=1.3 756000=982800

Q? and about. max=1.3 893000=1160900

Q in. max \u003d q in V (t v.r?t n.v), (7)

where q in - specific heat consumption for ventilation, W / (m 3 K);

t n.v? estimated outdoor air temperature for ventilation design, o C; for Kazan according to table 1.3 t present \u003d -18 o C

To reduce the calculated heat consumption for ventilation, the minimum outdoor temperature, which is used to calculate ventilation units, t n.v. is taken, as a rule, higher than the calculated temperature for heating t n.d. According to current standards, the design outdoor air temperature for ventilation design is defined as the average temperature of the coldest period, which is 15% of the duration of the entire heating period. The only exceptions are industrial workshops with a large emission of hazards, for which t n.v. taken equal to t n.o (such shops include iron foundry, steel foundry, thermal, forge, copper foundry, metal coating shop)

Q A c. max \u003d 0.113 18750 (18 + 18) \u003d 76275

Q b c. max =0.8 8000 (16+18)=217600

Q max \u003d 0.15 37500 (16 + 18) \u003d 191250

Q max \u003d 0.15 37500 (16 + 18) \u003d 191250

Q and c. max =0.1 50000 (18+18)=180000

where 1.2 is a coefficient that takes into account the cooling of hot water in subscriber hot water supply systems;

m - the number of showers, pcs;

a - the rate of consumption of hot water in the shower, a \u003d 60 l / person;

t cm1 - temperature of the mixture of hot and cold water in the shower t cm1 \u003d 37 ° C;

t x.v - cold temperature tap water t x.v =5 about C;

n - number of washbasins, pcs;

b - hot water consumption rate for the washbasin, b=5 l/h;

t cm2 - temperature of the mixture of hot and cold water in the washbasin t cm2 =35 o C;

c p is the heat capacity of water c p = 4.19 kJ/(kg K);

All calculations of thermal loads are summarized in table 3

Table 3 - Estimated thermal loads enterprises

Designation	Purpose of buildings
	Administrative
	Dining room
	machine shop
	machine shop
	Repair shop

3. Plotting heat consumption graphs

The graph of heat consumption for certain types of heat consumption and the total graph of heat consumption are built on three points corresponding to three average daily outdoor temperatures: t n, t n.v and t n.o.

At the same time, it should be taken into account that in buildings with internal heat release, the beginning heating season occurs at a lower temperature t n, o C

To determine the missing heat loads for heating and ventilation, the following formulas for recalculating heat loads are used:

The calculation is carried out separately for each building for outdoor temperatures of +8 o C, +5.2 o C, +4.65 o C, 0 o C, -2 o C, -14 o C, followed by summation by load type.

The calculation results are summarized in Table 4.

Table 4 - Calculation of loads for plotting heat consumption

Designation	Purpose of buildings	Heat consumption, W
	Administrative
	Dining room
	machine shop
	machine shop
	Repair shop
for all buildings

The heat load on hot water supply is year-round, during the heating period it is conditionally assumed to be constant, independent of the outside temperature. Therefore, the graph of heat consumption for hot water supply is a straight line parallel to the x-axis.

In the summer period (the range of standing time t n from n about to n = 8400 h) there are no heat loads for heating and ventilation, the load on hot water supply will be 80% of the winter load on hot water supply

The right side of the graph represents the dependence of the total heat load corresponding to certain average daily outdoor temperatures (from the left side of the graph) on the duration of these temperatures (the number of hours during the heating period with average daily outdoor temperatures equal to or below the data).

To build the right side of the graph, we determine the duration of standing temperatures for Kazan

Table 5 - Duration of standing outdoor temperatures

Based on the data obtained, we build an annual heat consumption graph for the duration of heat loads.

4. Determination of the estimated costs of network water

heat network water heating

The estimated costs of network water are determined separately for each type of load

Estimated consumption of network water for heating G o, kg / s

where f p, f o - the temperature of the network water in the supply and return pipelines at a temperature t n.o;

с - heat capacity of water, kJ/(kg K)

Estimated consumption of network water for ventilation G in, kg / s

where is f? p, f? o - the temperature of the network water in the supply and return pipelines at a temperature t n.v (except for buildings C, D, D, E, N, P for which the estimated costs of the network water are calculated at a temperature t n.o), we determine from the schedule of the TsKR vacation warmth

Estimated consumption of network water for hot water supply G hw, kg / s

where is f? p, f? o - network water temperature in the supply and return pipelines at a temperature t n.i; determined from the schedule of the CCR heat supply

The estimated costs of network water for each building are summarized in Table 6.

Table 6 - Estimated consumption of network water

Designation	Purpose of buildings
	Administrative
	Dining room
	machine shop
	machine shop
	Repair shop

To plot the consumption of network water, except for the calculated ones, i.e. maximum, the same formulas are used to determine other characteristic values ​​of network water flow rates.

We present the calculation in table 7

Table 7 - Consumption of network water depending on t outside air

Designation	Purpose of buildings	Network water consumption, kg/s
	Administrative
	Dining room
	machine shop
	machine shop
	Repair shop
for all buildings

Based on the obtained data, we build graphs of network water consumption for each type of load for all buildings, as well as the total graph of network water consumption for all types of load

5. Hydraulic calculation of the heat network

The main task of hydraulic calculation is to determine the diameters of pipelines, as well as pressure losses in sections of heating networks. Hydraulic calculation closed system The heat supply is carried out for the supply pipeline, taking the diameter of the return pipeline and the pressure drop in it to be the same as in the supply pipeline.

Before performing a hydraulic calculation, a design scheme for heat networks is developed. The section numbers are put on it (first along the main line, and then along the branches), coolant flow rates, kg / s, section lengths, m. The main line is the most extended and loaded branch of the network from the heat source (connection point) to the most remote consumer.

The calculation consists of two stages: preliminary and verification

5.1 Preliminary calculation

We determine the coefficient that takes into account the proportion of pressure losses in local resistances b

where G is the flow rate of the coolant in the area, kg/s.

We preliminarily determine the approximate pressure loss R l, Pa / m

where Dr n - the value of specific friction losses, Pa / m, we accept according to the recommendations:

On sections of the main highway 20-40, but not more than 80 Pa / m;

On branches - according to the available pressure drop, but not more than 300 Pa / m

The diameter of the pipeline is determined by the formula

where is the coefficient determined according to Appendix 7; for pipes with equivalent roughness k e =0.0005;

G - coolant flow in the area, kg / s

The data obtained as a result of the calculation are summarized in table 8

Table 8 - Preliminary hydraulic calculation

						d standard	Speed
						d n Chd st, mm

Assuming that the density of water is 1000 kg / m 3, we check the speed of water in the pipeline, which should not exceed 3.5 m / s

5.2 Verification calculation

After determining the diameters of the heat pipelines, an installation scheme is developed, which consists in arranging fixed supports, compensators and shut-off and control valves on the route of the heating networks. In the areas between the nodal chambers, i.e., the chambers in the branch nodes, fixed supports are placed, the distance between which depends on the diameter of the heat pipe, the type of compensator and the method of laying heat networks. A fixed support is installed in each nodal chamber. A compensator is provided in the area between two fixed supports. Turns of the heating network route at an angle of 90-130° are used for self-compensation of temperature elongations, and fixed supports are installed in places of turns at an angle of more than 130°. Fixed supports are placed on heat pipes of larger diameter, stop valves installed on all branches and on the main sections through one or two branches. In chambers on branches to individual buildings with a branch diameter of up to 50 mm and a length of up to 30 m, it is allowed not to install stop valves. In this case, fittings should be provided that ensure the shutdown of a group of buildings with a total heat load of up to 0.6 MW.

Determine the actual linear specific pressure drop R? l, Pa/m:

Where A b R - coefficient determined according to Appendix 7

A b R =13,62 10- 6

Determine the equivalent length of local resistances, m

where is A? - coefficient determined according to Appendix 7

Uo - the sum of the coefficients of local resistances installed on the site.

plot 1:

Uo \u003d 1 + 1.7 + 0.5 \u003d 3.2

plot 2:

Tee-pass, gate valve, P-arr. compensator with smooth bends

Uo \u003d 1 + 1.7 + 0.5 \u003d 3.2

plot 3:

Tee-pass, gate valve (2 pcs), two-seam welded elbow 90 °,

P-arr. compensator with smooth bends

Uo=1+2 0.5+0.6+1.7=4.3

plot 4:

Uo=1.5+2 0.5=2.5

plot 5:

Branch tee, gate valve (2 pcs)

Uo=1.5+2 0.5=2.5

plot 6:

Branch tee, gate valve (2 pcs)

Uo=1.5+2 0.5=2.5

plot 7:

Branch tee, gate valve (2 pcs)

Uo=1.5+2 0.5=2.5

Then we determine the pressure loss in the area, Pa

After determining the pressure loss in each section of the heating network, we calculate the pressure in the supply H p i and return H about i pipelines, as well as the available pressure H p i at the end of each section.

At the end of the first section for the supply line H p1, Pa, is determined by the formula:

N p1 \u003d N n -Dr 1 (22)

where N n - pressure in the supply line at the connection point

For subsequent sections, the final pressure of the section from which the calculated one exits is taken as the initial pressure.

The pressure at the beginning of the first section for the return line H o1, m.a.c., is determined by the formula:

N o1 \u003d N to + Dr 1 (23)

where N to - pressure in the return line at the connection point

For subsequent sections, the initial pressure of the section from which the calculated one exits is taken as the final pressure.

Available pressure on the site H p, Pa

H p i \u003d H p i + H o i (24)

We summarize the calculation in table 9

Table 9 - Verification calculation of the heat network

When linking branches, the diameters of the pipeline in each section are selected so that the pressure loss, Dr, on the branches is approximately the same. For this scheme, the following conditions must be met

Dr 3 \u003d Dr 6 \u003d Dr 7 (1216.02 \u003d 1085.01 \u003d 1125.36)

Dr 4 \u003d Dr 5 \u003d Dr 2-7 (3615.77 \u003d 3483.9 \u003d 3593.7)

The discrepancy between the largest and smallest value of the first equality is:

The discrepancy between the largest and smallest value of the second equality:

Since the difference does not exceed 10%, we assume that the required equalities are satisfied.

6. Building a piezometric graph

After performing the hydraulic calculation of water heating networks, they begin to plot pressures for the calculated main and characteristic branches. The pressure measured from the axis of the heat pipe laying is called piezometric, and the pressure graph is called a piezometric graph.

The piezometric graph allows you to: determine the pressure in the supply and return pipelines, as well as the available pressure at any point in the heating network; taking into account the terrain, the available pressure and the height of the buildings, select consumer connection schemes; select automatic regulators, elevator nozzles, throttle devices for local heat consumption systems; select mains and make-up pumps.

Piezometric graphs are built for the hydrostatic and hydrodynamic regimes of the heat supply system. The origin of coordinates is taken as the lowest elevation of the terrain contours. In the accepted scale, the terrain along the heating main and the height of the attached buildings are depicted. A static pressure line is built, the value of which should be at least 5 m higher than the local heat consumption systems, ensuring their protection from "exposing", and at the same time should be less than 10 m (or more) of the maximum operating pressure for local systems .

The value of the maximum working pressure of local heat consumption systems is: for heating systems with steel heaters and for heaters - 80 m; for heating systems with cast-iron radiators - 60 m; for independent connection schemes with surface heat exchangers - 100 m.

The hydrostatic head in heat supply systems with water as the heat carrier must be determined for a network water temperature of 100 °C.

Then proceed to the construction of head graphs for the hydrodynamic regime. On the ordinate axis, first, the difference between the lowest elevation of the terrain and the elevation of the axis of the heat pipe in the chamber for connecting the industrial enterprise to the main networks is plotted, then the values ​​​​of the initial and final pressures of the heating network in this chamber (H p and H o). After that, pressure graphs of the supply and return lines of the heating network are plotted based on the data in Table. 9.

Under the piezometric graph, a straightened single-line diagram of the heating main with branches is placed, the numbers and lengths of sections, pipeline diameters, coolant flow rates, available pressures at nodal points are indicated.

To build a piezometric graph, the initial, H p, final, H o and available, H p pressure in the areas, are translated into m. according to the formula:

where g - free fall acceleration, m/s 2 , g=9.81;

c - water density, kg / m 3, taken equal to 1000.

Pressure in the supply, h n, m.w.o.st., and return, h k, m.w.st., pipeline at the connection point

The translation results are summarized in table 10

	at the end of the lesson	at the beginning of the school

7. The choice of schemes for connecting buildings to the heating network

The choice of schemes for connecting heating systems to a heating network is made on the basis of a piezometric graph.

In this case, building A must be connected according to an independent scheme, since its absolute elevation is higher than the pressure line in the return pipeline. The remaining buildings can be connected to the system according to a dependent scheme with an elevator, since the available pressure in the system is more than 15 m.a.c., however, when taking into account current trends heat supply, it is most preferable to connect them according to a dependent scheme with pump mixing.

8. Hydraulic calculation of steam pipelines

The task of hydraulic calculation of steam pipelines is to determine the diameters of pipelines and pressure losses by sections, based on the steam flow rate, the available pressure drop (pressure difference at the beginning P n and end P k of the steam pipeline), taking into account the change in steam density due to pressure drop and changes in steam temperature due to losses heat in environment.

For hydraulic calculation, a calculation and installation diagram of steam pipelines is developed by analogy with the diagrams of a heat network.

The calculation consists of preliminary and verification

8.1 Preliminary calculation

In the preliminary calculation, it is considered that pressure losses along the length of the steam pipeline occur evenly. Then the average specific pressure drop R, Pa/m, is found by the formula

where R n, R k - steam pressure at the beginning and at the end of the steam pipeline, Pa;

Y? - the length of the steam pipeline (from the connection chamber to the most distant consumer), m;

b cf - average coefficient of local pressure losses

For a steam pipeline consisting of sections with different steam flow rates, the following is determined:

where b i , ? i - coefficient of local pressure losses and section length

where G - steam consumption in the area under consideration, t/h;

z - coefficient equal to 0.05..0.1 for steam networks; accept z=0.07

Approximate drop in steam pressure in the area, Pa

Steam pressure at the end of the design section, Pa

Hydraulic calculation of steam pipelines is carried out according to the average steam density in the calculated section, kg / m 3

where c n, c k - vapor density at the beginning and at the end of the section, determined by the corresponding pressure and temperature of the vapor, kg / m 3.

In the preliminary calculation, the drop in the temperature of superheated steam for every 100 m is assumed to be Df = 2.0 ... 2.5 o C.

Steam temperature at the end of the calculated section, ° С

Average steam temperature in the area, o C

Steam pipeline diameter, m

where is the coefficient determined according to Appendix 7; for pipes with equivalent roughness k e = 0.0002

The data obtained as a result of the calculation are summarized in table 11

Table 11 - Initial calculation of pressure drop across the steam pipeline

Since there are no indications of the superheat temperature of the steam, we assume that the steam is initially dry and saturated.

Let's determine the diameters of the steam pipelines by presenting the calculation in the form of table 12

Table 12 - Determination of steam pipe diameters

	s n, kg / m 3	with k, kg / m 3	s cf, kg / m 3

The conditions are satisfied, therefore, the diameters of the steam pipelines for the sections are chosen correctly.

8.2 Verification calculation

By analogy with hydraulic calculation heating network, the standard diameter of the steam pipeline is determined and its wiring diagram is drawn up.

Local resistances for each section are determined according to the wiring diagram:

plot 1:

Tee-pass, gate valve, P-arr. compensator with smooth bends

Uo \u003d 1 + 1.7 + 0.5 \u003d 3.2

plot 2:

Tee-pass, gate valve (2 pcs), P-arr. compensator with smooth bends, welded two-seam bend 90 °

Uo \u003d 1 + 1.7 + 0.5 2 + 0.6 \u003d 4.3

plot 3:

Branch tee, gate valve (2 pcs)

Uo=1.5+2 0.5=2.5

plot 4:

Branch tee, gate valve (2 pcs)

Uo=1.5+2 0.5=2.5

We find the actual values ​​of the specific pressure loss R? l, Pa/m:

Where A R - coefficient determined according to the application according to adj. 7; for pipes with equivalent roughness k e = 0.0002 A R =10,6 10- 3

Using formulas (20)-(21), we determine the equivalent length of local resistances and the vapor pressure at the end of the calculated section.

A value? determined according to Appendix 7 for pipes with equivalent roughness k e \u003d 0.0002 A? =76.4.

The definition of the actual pressure loss for each section is presented in the form of table 13

Table 13 - Determination of actual pressure losses

				s cf, kg / m 3

The actual steam temperature at the end of the calculated section is determined by the formula

where q i - specific heat losses by an insulated steam pipeline, W / m, are determined according to Appendix 9

c i - specific heat capacity of steam, corresponding to the average steam pressure in the area, kJ / (kg K);

G i - steam consumption in the area, t/h

We present the calculation in the form of a table 14

Table 14 - Determination of steam temperature at the end of the section

					s, kJ/(kg K)

Recalculation is not required, since the recommended speed is observed for the selected diameters. During the calculation, it was found that condensate may fall out at the end sections (f c i is lower than the saturation temperature of the steam corresponding to the pressure P c i), therefore, steam traps must be installed along the entire route.

9. Hydraulic calculation of the condensate pipeline

The hydraulic calculation of the condensate pipeline is carried out similarly to the pipelines of water heating networks.

The diameter of the condensate pipeline is determined by the condensate flow rate and the specific pressure drop along the length R l, which should be no more than 100 Pa / m.

First of all, the main settlement highway is calculated, then the remaining sections are calculated with the obligatory linking of all branches.

9.1 Preliminary calculation of the condensate pipeline

We carry out the calculation according to the formulas given in paragraph 5.1 on the basis of the calculation scheme.

We determine according to Appendix 7; for pipes with equivalent roughness k e = 0.0002

The data obtained as a result of the calculation are summarized in table 15

Table 15 - Preliminary calculation of the condensate pipeline

						d standard	Speed
						d n Chd st, mm

9.2 Verification calculation of the condensate line

We carry out the calculation according to the formulas given in clause 5.2

Odds A b R , A? determined according to Appendix 7

A b R =10,92 10- 6

According to the wiring diagram, we determine the local resistances for each section:

plot 1:

Tee-pass, gate valve, P-arr. compensator with smooth bends

Uo \u003d 1.5 + 1.7 + 0.5 \u003d 3.7

plot 2:

Tee-pass, gate valve (2 pcs.), P-arr. compensator with smooth bends, welded two-seam bend 90 °

Uo=1.5+1.7+0.5 2+0.6=4.8

plot 3:

Branch tee, gate valve (2 pcs)

Uo=2+2 0.5=3.0

plot 3:

Branch tee, gate valve (2 pcs)

Uo=2+2 0.5=3.0

The calculation results are summarized in table 16

Table 16 - Verification calculation of the condensate pipeline

10. Building a longitudinal profile of the heating network

A longitudinal profile is built along the heating network route. On the longitudinal profile they show: marks of the earth's surface (design - with a solid line, existing - with a dashed line); intersected network engineering and structures; marks of the bottom of the pipe of the heating network, the bottom and ceiling of the channel; the depth of the heat pipe; slope and length of sections of the heating network; heat pipe diameter and channel type; in addition, a detailed plan of the route is given, indicating the angles of rotation, branches, fixed supports, compensators and thermal chambers. With the above-ground laying method, marks are given for the top of the supporting structure and the bottom of the heat pipe.

The slope of the heat pipe, regardless of the laying method, must be at least 0.002. The number of junctions of sections with reverse slopes should be as small as possible.

At the lowest points of the heat pipeline, drainage outlets are provided, and at the highest points, air vents are provided, which are placed in the chambers.

According to TKP 45-4.02-182-2009 (02250) Heat networks, the depth of heat networks from the ground to the top of the channel overlap must be at least 0.5 m, to the top of the chamber overlap - at least 0.3 m, to the top of the heat pipe shell at channelless laying - at least 0.7 m. The height of the above-ground laying of heat pipelines from the ground surface to the bottom of the insulating structure must be at least 0.5 m, in some cases this distance may be reduced to 0.35 m.

11. Thermal calculation

task thermal calculation V term paper is the determination of the thickness of the heat-insulating layer according to the formula:

where d is the outer diameter of the pipeline, m;

l and - coefficient of thermal conductivity of the heat-insulating layer, W / (m o C);

R and - thermal resistance of the insulation layer, (m o C) / W;

According to the initial data for the heating network:

thermal insulation - bitumen perlite (l and \u003d 0.12 W / (m o C))

heating network laying - channelless

Thermal resistance of the insulation layer:

where Rsum is the total thermal resistance of the insulation layer and other additional thermal resistances in the path of the heat flow, (m o C) / W

where t w is the average temperature of the coolant over the period of operation, o C

for the supply line - 90

for the return line - 70

t e - average annual ambient temperature, o C; with channelless laying - the average annual temperature of the soil; for the city of Kazan t gr \u003d + 1 o C;

q e - standard linear heat flux density, W/m

The second component depends on the method of laying the heating network.

For underground channel laying:

R p.s - thermal resistance of the surface of the insulating layer, m ° C / W, determined by the formula:

b e - heat transfer coefficient from the surface of thermal insulation to the surrounding air, W / (m 2 ° C), which is taken when laying in channels b e \u003d 8 W / (m 2 ° C).

Thermal resistance of the channel surface (R p.k), m ° C / W, is determined by:

d w.e. - internal equivalent diameter of the channel, m

The thermal resistance of the channel wall (R k), m ° C / W, is determined by:

l st - thermal conductivity of the channel wall, for reinforced concrete l st \u003d 2.04 W / (m 2 ° C);

d A.D. - outer equivalent diameter of the channel, determined by the outer dimensions of the channel, m.

The calculation is carried out for each pipeline separately

Ground resistance:

where gr is the coefficient of thermal conductivity of the soil, we take it according to

2.5 W/(m o C)

h - depth of laying the axis of the heat pipe, h=1m

dne is the outer equivalent diameter, we take it conditionally equal to the diameter of the heat pipe together with the limiting thickness of the insulation for these conditions.

Additional thermal resistance, taking into account the mutual influence of pipes in channelless laying:

For the supply pipeline:

For the return pipeline:

where b is the distance between the axes of the pipelines, m; taken depending on their nominal bore diameters according to Table 11.1

First, let's calculate the total thermal resistance of the insulation layer and other additional thermal resistances in the path of the heat flow. We present the calculation in the form of a table 17

Table 17 Total thermal resistance of the insulation layer

	d n Chd st, mm

We calculate the value of the second component and the total resistance of thermal insulation, the calculation will be presented in the form of table 18.

Table 18. Calculation of the total resistance of thermal insulation

Now we calculate the thickness of the thermal insulation and select the standard values. We present the calculation in the form of a table 19

Table 19. Calculation of the thickness of thermal insulation.

Since there are no instructions regarding the laying of steam and condensate networks in the assignment for the course work, we take for calculation the most common method for laying technological steam pipelines for enterprises - above-ground laying.

Calculation of the thickness of the insulation layer in we go by the formula (37)

t w - average temperature of the coolant over the period of operation

t e - average annual ambient temperature, C, for air laying of networks we accept the average ambient temperature for the period of operation: t e \u003d 4.1 o C

When laying the route in the air, we get:

where b o is the heat transfer coefficient from the surface of thermal insulation to the surrounding air, we take it equal to b o \u003d 26 W / (m o C)

d - outer diameter of the pipeline, m

For isolation we take mineral wool with a thermal conductivity of 0.08 W / (m o C). The determination of the thickness of thermal insulation for a steam pipeline is presented in the form of table 20.

Table 20. Determining the thickness of thermal insulation for a steam pipeline

Determination of the thickness of thermal insulation for the condensate pipeline is presented in the form of table 21

Table 21. Determining the thickness of thermal insulation for a condensate pipeline

Literature

1. Sources and systems of heat supply of industrial enterprises: method. instructions for coursework and practice. one-on-one lessons. discipline for students of specialties 1-43 01 05 "Industrial heat power engineering" and 1-43 01 07 " Technical operation power equipment of organizations "full-time and part-time forms of education / I.R. Pogartsev, T.S. Yufanova, E.M. Zvezdkina. - Gomel: GGTU named after P.O. Sukhoi, 2008.-39p.

2. Designer's guide. Design of thermal networks / ed. A.A. Nikolaev. - Moscow: Stroyizdat, 1965. - 360 p.

3. Sokolov E.Ya. Heat supply and thermal networks: textbook. for universities / E.Ya. Sokolov. - 7th ed. - Moscow: MEI Publishing House, 2001. - 472 p.

4. V.I. Manyuk, Ya.I. Kaplinsky, E.B. Hizh, A.I. Manyuk, V.K. Ilyin Adjustment and operation of water heating networks / Handbook. 3rd edition - Stroyizdat, Moscow, 1988

5. TCP 45.4.02-182-2009 (02250) Heating networks / Ministry of Architecture and Construction of the Republic of Belarus Minsk 2010

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Ministry of Education and Science

SEI HPE "Bratsk State University"

Faculty of Energy and Automation

Department of Industrial Heat Power Engineering

Discipline abstract

"Heat and ventilation"

Modern systems heat supply

Development prospects

Performed:

St group TGV-08

ON THE. Snegirev

Supervisor:

Professor, Ph.D., Department of PTE

S.A. Semenov

Bratsk 2010

Introduction

1. Types of central heating systems and the principles of their operation

4.2 Gas heating

4.3 air heating

4.4 Electric heating

4.5 Piping

4.6 Boiler equipment

5. Prospects for the development of heat supply in Russia

Conclusion

List of used literature

Introduction

Living in temperate latitudes, where the main part of the year is cold, it is necessary to provide heat supply to buildings: residential buildings, offices and other premises. Heat supply provides comfortable living if it is an apartment or a house, productive work if it is an office or a warehouse.

First, let's figure out what is meant by the term "Heat supply". Heat supply is the supply of building heating systems hot water or by ferry. The usual source of heat supply is CHP and boiler houses. There are two types of heat supply for buildings: centralized and local. With a centralized supply, certain areas (industrial or residential) are supplied. For effective work centralized heating network, it is built by dividing it into levels, the work of each element is to perform one task. With each level, the task of the element decreases. Local heat supply - the supply of heat to one or more houses. Centralized networks heating supplies have a number of advantages: reduced fuel consumption and cost reduction, use of low-grade fuel, improved sanitation of residential areas. The district heating system includes a source of thermal energy (CHP), a heat network and heat-consuming installations. CHP plants produce heat and energy in combination. Sources of local heat supply are stoves, boilers, water heaters.

Heating systems are characterized by different water temperatures and pressures. It depends on customer requirements and economic considerations. With an increase in the distance over which it is necessary to “transfer” heat, economic costs increase. At present, the heat transfer distance is measured in tens of kilometers. Heat supply systems are divided according to the volume of heat loads. Heating systems are seasonal, and hot water systems are permanent.

1. Types of central heating systems and the principles of their operation

District heating consists of three interrelated and sequential stages: preparation, transportation and use of the heat carrier. In accordance with these stages, each system consists of three main links: a heat source (for example, a combined heat and power plant or a boiler house), heat networks (heat pipelines) and heat consumers.

In decentralized heat supply systems, each consumer has its own heat source.

Heat carriers in central heating systems can be water, steam and air; the corresponding systems are called systems of water, steam or air heating. Each of them has its own advantages and disadvantages. heat supply central heating

The advantages of a steam heating system are its significantly lower cost and metal consumption compared to other systems: when condensing 1 kg of steam, approximately 535 kcal is released, which is 15-20 times more than the amount of heat released when 1 kg of water cools in heating devices, and therefore steam pipelines have a much smaller diameter than pipelines of a water heating system. In steam heating systems, the surface of the heating devices is also smaller. In rooms where people stay periodically (industrial and public buildings), the steam heating system will make it possible to produce heating intermittently and there is no danger of freezing of the coolant with subsequent rupture of pipelines.

The disadvantages of the steam heating system are its low hygienic qualities: dust in the air burns on heaters heated to 100 ° C or more; it is impossible to regulate the heat transfer of these devices and for most of the heating period the system must work intermittently; the presence of the latter leads to significant fluctuations in air temperature in heated rooms. Therefore, steam heating systems are arranged only in those buildings where people stay periodically - in baths, laundries, shower pavilions, train stations and clubs.

Air heating systems consume little metal, and they can ventilate the room at the same time as heating the room. However, the cost of an air heating system for residential buildings is higher than other systems.

Water heating systems have a high cost and metal consumption compared to steam heating, but they have high sanitary and hygienic qualities that ensure their wide distribution. They are arranged in all residential buildings with a height of more than two floors, in public and most industrial buildings. Centralized regulation of heat transfer of devices in this system is achieved by changing the temperature of the water entering them.

Water heating systems are distinguished by the method of water movement and design solutions.

According to the method of moving water, systems with natural and mechanical (pumping) motivation are distinguished. Water heating systems with natural impulse. The schematic diagram of such a system consists of a boiler (heat generator), a supply pipeline, heating devices, a return pipeline and an expansion vessel. The water heated in the boiler enters the heating devices, gives them part of its heat to compensate for heat losses through the external fences of the heated building, then returns to the boiler and then the water circulation is repeated. Its movement occurs under the influence of a natural impulse that occurs in the system when the water is heated in the boiler.

The circulation pressure created during the operation of the system is spent on overcoming the resistance to the movement of water through the pipes (from the friction of water against the walls of the pipes) and on local resistances (in bends, taps, valves, heaters, boilers, tees, crosses, etc.) .

The value of these resistances is the greater, the higher the speed of water movement in the pipes (if the speed doubles, then the resistance quadruples, i.e., in a quadratic dependence). In systems with natural induction in buildings with a small number of storeys, the magnitude of the effective pressure is small, and therefore they should not be allowed to high speeds movement of water in pipes; therefore, pipe diameters must be large. The system may not be economically viable. Therefore, the use of systems with natural circulation is allowed only for small buildings. The range of such systems should not exceed 30 m, and the value of k should not be less than 3 m.

When the water in the system is heated, its volume increases. To accommodate this additional volume of water in heating systems, an expansion vessel 3 is provided; in systems with upper wiring and natural impulse, it simultaneously serves to remove air from them, which is released from the water when it is heated in boilers.

Water heating systems with pump impulsion. The heating system is always filled with water and the task of the pumps is to create the pressure necessary only to overcome the resistance to the movement of water. In such systems, natural and pumping impulses operate simultaneously; total pressure for two-pipe systems with top wiring, kgf/m2 (Pa)

For economic reasons, it is usually taken in the amount of 5-10 kgf / m2 per 1 m (49-98 Pa / m).

The advantages of systems with pumping induction are the reduction in the cost of pipelines (their diameter is smaller than in systems with natural induction) and the ability to supply heat to a number of buildings from one boiler house.

The devices of the described system, located on different floors of the building, operate in different conditions. The pressure p2, which circulates water through the device on the second floor, is about twice as high as the pressure p1 for the device on the lower floor. At the same time, the total resistance of the pipeline ring passing through the boiler and the device on the second floor is approximately equal to the resistance of the ring passing through the boiler and the device on the first floor. Therefore, the first ring will work with excess pressure, more water will enter the device on the second floor than it is necessary according to the calculation, and accordingly the amount of water passing through the device on the first floor will decrease.

As a result, overheating will occur in the room of the second floor heated by this device, and underheating will occur in the room of the first floor. To eliminate this phenomenon, special methods calculation of heating systems, as well as use installed on hot eyeliner to appliances with double adjustment taps. If you close these taps at the appliances on the second floor, you can completely extinguish the excess pressure and thereby adjust the water flow for all appliances located on the same riser. However, the uneven distribution of water in the system is also possible for individual risers. This is explained by the fact that the length of the rings and, consequently, their total resistance in such a system for all risers are not the same: the ring passing through the riser (closest to the main riser) has the least resistance; the greatest resistance has the longest ring passing through the riser.

It is possible to distribute water to separate risers by appropriately adjusting the plug (pass-through) taps installed on each riser. For water circulation, two pumps are installed - one working, the second - spare. Near the pumps, they usually make a closed, bypass line with a valve. In the event of a power outage and the pump stops, the valve opens and the heating system operates with natural circulation.

In a pump-driven system, the expansion tank is connected to the system before the pumps, and therefore the accumulated air cannot be expelled through it. To remove air in previously installed systems, the ends of the supply risers were extended with air pipes on which valves were installed (to turn off the riser for repairs). The air line at the point of connection to the air collector is made in the form of a loop that prevents the circulation of water through the air line. Currently, instead of such a solution, air valves are used, screwed into the top plugs of radiators installed on the top floor of the building.

Heating systems with lower wiring are more convenient in operation than systems with upper wiring. So much heat is not lost through the supply line and water leakage from it can be detected and eliminated in a timely manner. The higher the heater is placed in systems with lower wiring, the consequently more pressure present in the ring. The longer the ring, the greater its total resistance; therefore, in a system with a lower wiring excess pressure appliances on the upper floors have much less than in systems with top wiring and, therefore, their adjustment is easier. In systems with a lower wiring, the magnitude of the natural impulse decreases due to the fact that, due to cooling in the supply risers, the ode begins to slow down its movement from top to bottom, so the total pressure acting in such systems

Currently, single-pipe systems are widely used, in which radiators are connected to one riser with both connections; such systems are easier to install and provide more uniform heating of all heating devices. The most common single-pipe system with bottom wiring and vertical risers.

The riser of such a system consists of lifting and lowering parts. Three-way valves can pass the calculated amount or part of the water into the devices in the latter case, the rest of its amount passes, bypassing the device, through the closing sections. The connection of the lifting and lowering parts of the riser is made by a connecting pipe laid under the windows of the upper floor. Air cocks are installed in the upper plugs of the devices located on the upper floor, through which the mechanic removes air from the system during the start-up of the system or when it is abundantly replenished with water. In single-pipe systems, the water passes through all the appliances in sequence, and therefore they must be carefully adjusted. If necessary, the heat transfer of individual devices is adjusted using three-way valves, and the water flow through individual risers - through passage (plug) valves or by installing throttling washers in them. If an excessively large amount of water is supplied to the riser, then the heaters of the riser, which are the first in the direction of water movement, will give off more heat than is necessary according to the calculation.

As you know, the circulation of water in the system, in addition to the pressure created by the pump and natural impulse, is also obtained from the additional pressure Ap, resulting from the cooling of water when moving through the pipelines of the system. The presence of this pressure made it possible to create apartment water heating systems, the boiler of which is not buried, but is usually installed on the kitchen floor. In such cases, the distance, therefore, the system works only due to the additional pressure resulting from the cooling of the water in the pipelines. The calculation of such systems differs from the calculations of heating systems in a building.

Systems of apartment water heating are now widely used instead of furnace heating in one- and two-story buildings in gasified cities: in such cases, instead of boilers, automatic gas water heaters(LGV), providing not only heating, but also hot water supply.

2. Comparison of modern heat supply systems of a thermal hydrodynamic pump type TC1 and a classic heat pump

After the installation of hydrodynamic heat pumps, the boiler room will become more like pumping station than for a boiler room. Eliminates the need for a chimney. There will be no soot and dirt, the need for maintenance personnel will be significantly reduced, the automation and control system will completely take over the processes of managing heat production. Your boiler room will become more economical and high-tech.

Schematic diagrams:

Unlike a heat pump, which can produce a heat carrier with a maximum temperature of up to +65 °C, a hydrodynamic heat pump can heat the heat carrier up to +95 °C, which means that it can be easily built into already existing system building heat supply.

In terms of capital costs for the heat supply system, a hydrodynamic heat pump is several times cheaper than a heat pump, because does not require a low-potential heat circuit. Heat pumps and thermal hydrodynamic pumps, similar in name, but different in terms of the principle of transformation electrical energy into thermal.

Like a classic heat pump, a hydrodynamic heat pump has a number of advantages:

Profitability (a hydrodynamic heat pump is 1.5-2 times more economical than electric boilers, 5-10 times more economical than diesel boilers).

· Absolute environmental friendliness (the possibility of using a hydrodynamic heat pump in places with limited MPE standards).

· Complete fire and explosion safety.

· Does not demand water treatment. During operation, as a result of the processes taking place in the heat generator of a hydrodynamic heat pump, degassing of the coolant occurs, which has a beneficial effect on the equipment and devices of the heat supply system.

· Fast installation. If there is a connected electric power, installation of an individual heating point using a hydrodynamic heat pump can be produced in 36-48 hours.

· Payback period from 6 to 18 months, due to the possibility of installation in an existing heating system.

Time to overhaul 10-12 years old. The high reliability of the hydrodynamic heat pump is inherent in its design and confirmed by many years of trouble-free operation of hydrodynamic heat pumps in Russia and abroad.

3. Autonomous heating systems

Autonomous heat supply systems are designed for heating and hot water supply of single-family and detached residential buildings. An autonomous heating and hot water supply system includes: a heat supply source (boiler) and a network of pipelines with heating devices and water fittings.

Advantages autonomous systems heating supplies are as follows:

Lack of expensive external heating networks;

Possibility of quick implementation of installation and commissioning of heating and hot water supply systems;

low initial costs;

simplification of the solution of all issues related to construction, as they are concentrated in the hands of the owner;

· reduction of fuel consumption due to local regulation of heat supply and absence of losses in heat networks.

Such heating systems, according to the principle of accepted schemes, are divided into schemes with natural circulation of the coolant and schemes with artificial circulation of the coolant. In turn, schemes with natural and artificial circulation of the coolant can be divided into one- and two-pipe. According to the principle of coolant movement, schemes can be dead-end, associated and mixed.

For systems with natural induction of the coolant, schemes with upper wiring are recommended, with one or two (depending on the load and design features houses) main risers, with expansion tank installed on the main riser.

A boiler for one-pipe systems with natural circulation can be flush with the lower heaters, but it is better if it is buried, at least to the level concrete slab, in a pit or installed in the basement.

The boiler for two-pipe heating systems with natural circulation must be buried in relation to the lower heating device. The depth of penetration is specified by calculation, but not less than 1.5-2 m. Systems with artificial (pumping) induction of the coolant have a wider range of applications. You can design circuits with top, bottom and horizontal wiring of the coolant.

Heating systems are:

water;

air;

electric, including those with a heating cable laid in the floor of heated rooms, and accumulator thermal furnaces (designed with the permission of the energy supply organization).

Water heating systems are designed vertically with heating devices installed under window openings, and with heating pipelines embedded in the floor structure. In the presence of heated surfaces, up to 30% of the heating load should be provided by heating devices installed under window openings.

Apartment air heating systems combined with ventilation should allow operation in full circulation mode (no people) only on external ventilation (intensive domestic processes) or on a mixture of external and internal ventilation in any desired ratio.

The supply air undergoes the following treatment:

taken from the outside (in the volume sanitary standard per person 30 m3/h) mixed with recirculated air;

· it is cleared in filters;

heated in heaters;

It is supplied to the serviced premises through a network of air ducts made of metal or embedded in building structures.

Depending on the external conditions, the system must ensure the operation of the unit in 3 modes:

in the outdoor air

Full recirculation

on a mixture of external air recirculation.

4. Modern heating and hot water systems in Russia

Heaters are an element of the heating system, designed to transfer heat from the coolant to the air to the enclosing structures of the serviced premises.

A number of requirements are usually put forward for heating appliances, on the basis of which one can judge the degree of their perfection and make comparisons.

· Sanitary and hygienic. Heating appliances should, if possible, have a lower housing temperature, have smallest area horizontal surface to reduce dust deposits, allow unhindered removal of dust from the housing and enclosing surfaces of the room around them.

· Economic. Heating appliances should have the lowest reduced costs for their manufacture, installation, operation, and also have the lowest metal consumption.

· Architectural and construction. The appearance of the heater must correspond to the interior of the room, and the volume occupied by them must be the smallest, i.e. their volume per unit of heat flow should be the smallest.

· Production and installation. Maximum mechanization of work in the production and installation of heating devices should be ensured. Heating appliances. Heating appliances must have sufficient mechanical strength.

· Operational. Heating devices must ensure the controllability of their heat transfer and provide heat resistance and water tightness at the maximum allowable hydrostatic pressure inside the device under operating conditions.

· Thermotechnical. Heating appliances should provide the highest density of specific heat flux per unit area (W/m).

4.1 Water heating systems

The most common heating system in Russia is water. In this case, the heat is transferred to the premises with hot water contained in the heating devices. Most the usual way - water heating with natural water circulation. The principle is simple: water moves due to differences in temperature and density. Lighter hot water rises from the heating boiler upwards. Gradually cooling down in the pipeline and heating appliances, it becomes heavier and tends down, back to the boiler. The main advantage of such a system is independence from the power supply and a fairly simple installation. Many Russian craftsmen cope with its installation on their own. In addition, a small circulation pressure makes it safe. But for the system to work, pipes of increased diameter are required. At the same time, reduced heat transfer, limited range and a large amount of time required to start, make it imperfect and suitable only for small houses.

more modern and reliable schemes heating with forced circulation. Here water is set in motion by work circulation pump. It is installed on the pipeline supplying water to the heat generator and sets the flow rate.

Quick start of the system and, as a result, quick heating of the premises is an advantage pumping system. The disadvantages include that when the power is turned off, it does not work. And this can lead to freezing and depressurization of the system. The heart of the water heating system is the source of heat supply, the heat generator. It is he who creates the energy that provides heat. Such a heart - cauldrons on different types fuel. The most popular gas boilers. Another option is a diesel fuel boiler. Electric boilers compare favorably with the absence of an open flame and combustion products. Solid fuel boilers not convenient to use due to the need for frequent heating. To do this, it is necessary to have tens of cubic meters of fuel and space for its storage. And add here the labor costs for loading and harvesting! In addition, the heat transfer mode of a solid fuel boiler is cyclical, and the air temperature in heated rooms fluctuates markedly during the day. A place to store fuel supplies is also necessary for oil-fired boilers.

Aluminum, bimetal and steel radiators

Before choosing any heating device, it is necessary to pay attention to the indicators that the device must meet: high heat transfer, low weight, modern design, small capacity, light weight. The most main characteristic heater - heat transfer, that is, the amount of heat that should be in 1 hour per 1 square meter of heating surface. The best device is considered to be the one with the highest this indicator. Heat transfer depends on many factors: the heat transfer medium, the design of the heating device, the method of installation, the color of the paint, the speed of water movement, the speed of washing the device with air. All devices of the water heating system are divided by design into panel, sectional, convectors and columnar aluminum radiators or steel.

Panel heating appliances

Manufactured from cold rolled high quality steel. They consist of one, two or three flat panels, inside of which there is a coolant, they also have ribbed surfaces that heat up from the panels. Heating of the room occurs faster than when using sectional radiators. The above panel radiators water heating come with lateral or bottom connection. Side connection is used when replacing an old radiator with side connection or if the slightly unaesthetic appearance of the radiator does not interfere with the interior of the room.

Sectional water heating devices

Made from steel, cast iron or aluminium. They use the convective method of heating the room, that is, they give off heat due to the circulation of air through them. Air passes through the convector from top to bottom and heats up from a large number warm surfaces.

Convectors

Provide circulation of air in the room when warm air goes up and cold air on the contrary, it goes down and, passing through the convector, heats up again.

Steel water heating radiator can be both sectional and panel type. Steel is most often exposed to corrosion and therefore these radiators are most suitable for enclosed spaces. Two types of radiators are produced: with horizontal channels and with vertical channels.

Aluminum radiators

Aluminum radiators for water heating are lightweight and have good heat dissipation, aesthetic, but expensive. Often they don't last high pressure in system. Their advantage is that they heat the room much faster than cast-iron radiators do.

Bimetal radiators

Bimetallic water heating radiators consist of aluminum case and steel pipes through which the coolant moves. Their main advantage over other radiators is durability. Their operating pressure reaches up to 40 atm, while aluminum water heating radiators operate at a pressure of 16 atm. Unfortunately, at the moment on the European market it is very rare to find data for sale. bimetal radiators water heating.

Cast iron radiators columnar type - this is almost the most common type of radiators. They are durable and practical to use. Cast iron radiators are produced in two-column sections. These heaters can be operated at the highest working pressure. Their disadvantage is a lot of weight and inconsistency with the design of the room. The above radiators are used in systems with poor preparation of the coolant. They are quite inexpensive in price.

4.2 Gas heating

The next most frequently used type of heating in Russia country house- gas. In this case, heaters adapted for gas combustion are installed directly in heated rooms.

gas ovens economical and have high thermal performance. Distinctive feature such furnaces - the uniformity of heating of the outer surface. As additional sources of heat, gas fireplaces are used, which also give special comfort to the interior.

Dignity gas heating lies primarily in the relatively low cost of natural gas. Its use allows you to automate the process of fuel combustion, significantly increases the efficiency of heating equipment, and reduces operating costs. But it is explosive and unacceptable for self-manufacturing and installation.

4.3 Air heating

Air heating systems are distinguished depending on the method of creating air circulation: gravitational and fan. Gravity air system heating is based on the difference in air density at different temperatures. During the warm-up process, natural air circulation in the system occurs. The fan system uses electric fan, which increases the air pressure and distributes it through the air ducts and rooms (forced mechanical circulation).

The air is heated in heaters heated from the inside by water, steam, electricity or hot gases. The heater is placed either in a separate fan chamber (central heating system) or directly in the room that is heated (local system).

The absence of a freezing coolant makes this type of heating successful for houses with intermittent use. Air heating will quickly warm up the house, and automatic regulators will maintain the temperature you set. The disadvantages of such heating can only be attributed to the danger of the spread of harmful substances by moving air.

4.4 Electric heating

Systems of direct stationary electric heating are very reliable, environmentally friendly and safe. Up to 70% of low-rise buildings in Scandinavia and Finland are heated by electricity. Equipment for electric heating can be divided into 4 groups: - wall-mounted electric convectors; - ceiling heaters; - cable and film systems for floor and ceiling heating; - control thermostats and programmable devices.

This variety makes it easy to choose suitable option for each specific room. Equipment and operating costs for electrical systems are very low. Systems can automatically turn on and off to maintain the temperature at a given level. Let's say lower it to a minimum for the duration of your absence. This feature significantly saves energy costs. Rising prices for different kinds fuels make electric heating very attractive for owners of private houses. The disadvantage of electric heating systems is that you will have to install additional equipment to provide the house with hot water. In addition, we still have long blackouts, and the owners of such a system should consider an additional source of heating - just in case.

4.5 Piping

Pipelines for supplying coolant to heating appliances can be made of steel water and gas pipes, copper pipes and from polymeric materials ( metal-plastic pipes, polypropylene pipes and cross-linked polypropylene pipes). Lines made of steel pipes are not suitable for concealed connections to radiators. All other pipes can be "hidden" under finishing materials subject to certain system installation technologies. It should also be noted that it is not allowed to install a heating system from copper pipes if aluminum sectional radiators are selected as heating devices.

4.6 Boiler equipment

As a rule, heating of urban dwellings is provided from centralized boiler houses and city heating networks, while heating country houses is mainly carried out from own (autonomous) heat sources and only occasionally from a boiler house operating for a group of buildings.

The market for boiler equipment in Russia is quite saturated. Almost all leading Western companies producing boiler equipment have their own representative offices here. Although Russian boilers are widely represented on the market, they still cannot compete with imported samples in terms of consumer qualities. At the same time, almost all Western manufacturers develop and supply Russian market boilers adapted to our conditions:

multi-fuel boilers;

· gas boilers operating without electricity.

Multi-fuel boilers

Almost all companies produce boilers operating on liquid fuel and gas, and some companies add the option solid fuel. It should be noted that multi-fuel boilers, due to the design of the burner, are quite noisy.

gas boilers working without electricity

Now the majority of boilers are designed to work in heating systems with forced circulation of the coolant, and, in a typical case of a power outage in Russia, the boiler simply stops and does not work until there is electricity.

Boiler control systems

The control system for boiler equipment, depending on the purpose of the boiler room (only heating of one building, heating and hot water supply, the presence of underfloor heating circuits, heating and hot water supply of several buildings), can vary from the simplest, made on thermostatic controllers, to complex with microprocessor control.

5. Prospects for the development of heat supply in Russia

The main factors determining the prospects for the development of heat supply in Russia include:

1. A course towards restructuring the unified energy system with the formation of a 3-level system of enterprises: heat producers, heat networks and energy sellers. The restructuring will be accompanied by a redistribution of ownership in the energy complex in favor of private entrepreneurship. It is expected to attract large investments, including from abroad. In this case, the restructuring will affect the "large" energy sector.

2. Housing and communal reform associated with the reduction and removal of subsidies to the population in payment utilities, including thermal energy.

3. Stable economic growth in the construction industry.

4. Integration into the country's economy of advanced heat and power technologies of Western countries.

5. Revision of the regulatory framework for thermal power engineering, taking into account the interests of large investors.

6. Approximation of domestic prices for fuel and energy resources to world prices. Formation of a “deficit” of fuel resources of export potential in the domestic market, primarily natural gas and oil. Increasing the share of coal and peat in the country's fuel balance.

7. Formation of a balance of municipal and market mechanisms for the organization and management of regional heat supply.

8. Formation of modern accounting and billing systems in the market for the production, supply and consumption of thermal energy.

Conclusion

Russia belongs to the countries with a high level of heat supply centralization. Energy, environmental and technical advantage district heating over autonomous in a monopoly state property considered a priori. Autonomous and individual heat supply of individual houses was taken out of the scope of energy and developed according to the residual principle.

In the district heating system, CHPPs are widely used - enterprises for the combined generation of electricity and heat. Technologically, CHPPs are focused on the priority of power supply, the heat produced by the process is in demand to a greater extent in the cold season, and discharged into the environment - in the warm season. It is far from always possible to harmonize the modes of production of heat and electric energy with the modes of their consumption. Nevertheless, high level of the large power industry predetermined the “technological independence” and even a certain export potential of the country, which cannot be said about the small heat power industry. Low prices for fuel resources, economically unjustified price of thermal energy did not contribute to the development of "small" boiler building technologies.

Heat supply is an important industry in our life. It brings warmth to our home, provides coziness and comfort, as well as hot water supply, which is necessary every day in the modern world.

Modern heat supply systems significantly save resources, are more convenient to use, meet sanitary and hygienic requirements, are smaller in size and look more aesthetically pleasing.

Bibliography

1. http://www.rosteplo.ru

2. http://dom.ustanovi.ru

3. http://www.boatanchors.ru

4. http://whttp://www.ecoteplo.ru