The supply of heat to a room is associated with a simple temperature schedule. The temperature values ​​of the water supplied from the boiler room do not change in the room. They have standard values ​​and range from +70ºС to +95ºС. This temperature schedule for the heating system is the most popular.

Adjusting the air temperature in the house

Not everywhere in the country has centralized heating, so many residents install independent systems. Their temperature graph differs from the first option. In this case, temperature indicators are significantly reduced. They depend on the efficiency of modern heating boilers.

If the temperature reaches +35ºС, the boiler will operate at maximum power. It depends heating element, Where thermal energy can be picked up by exhaust gases. If the temperature values ​​are greater than + 70 ºС, then the boiler performance drops. In that case, in his technical specifications efficiency is indicated at 100%.

Temperature schedule and its calculation

What the graph will look like depends on the outside temperature. The more negative the outside temperature, the greater the heat loss. Many people do not know where to get this indicator. This temperature is prescribed in regulatory documents. The temperature of the coldest five-day period is taken as the calculated value, and the lowest value over the last 50 years is taken.

Graph of the dependence of external and internal temperatures

The graph shows the relationship between external and internal temperatures. Let's say the outside temperature is -17ºС. Drawing a line upward until it intersects with t2, we obtain a point characterizing the temperature of the water in the heating system.

Thanks to the temperature schedule, you can prepare the heating system even for the most severe conditions. It also reduces material costs for installation heating system. If we consider this factor from the point of view of mass construction, the savings are significant.

inside premises depends from temperature coolant, A Also others factors:

• Outside air temperature. The smaller it is, the more negatively it affects heating;
• Wind. When strong wind occurs, heat loss increases;
• The temperature inside the room depends on the thermal insulation of the structural elements of the building.

Over the past 5 years, construction principles have changed. Builders increase the value of a home by insulating elements. As a rule, this applies to basements, roofs, and foundations. These expensive measures subsequently allow residents to save on the heating system.

Temperature chart heating

The graph shows the dependence of the temperature of external and internal air. The lower the outside air temperature, the higher the coolant temperature in the system will be.

A temperature schedule is developed for each city during the heating season. In small settlements, a boiler room temperature schedule is drawn up, which ensures required quantity coolant to the consumer.

Change temperature schedule Can several ways:

• quantitative - characterized by a change in the flow rate of coolant supplied to the heating system;
• qualitative - consists of regulating the temperature of the coolant before supplying it to the premises;
• temporary - a discrete method of supplying water to the system.

The temperature schedule is a schedule of heating pipes that distributes the heating load and is regulated using centralized systems. There is also an elevated schedule, it is created for closed system heating, that is, to ensure the supply of hot coolant to connected objects. When using open system it is necessary to adjust the temperature schedule, since the coolant is consumed not only for heating, but also for domestic water consumption.

The temperature graph is calculated using simple method. Hto build it, necessary initial temperature air data:

• external;
• indoors;
• in the supply and return pipelines;
• at the exit of the building.

In addition, you should know the nominal thermal load. All other coefficients are standardized by reference documentation. The system is calculated for any temperature schedule, depending on the purpose of the room. For example, for large industrial and civil facilities a schedule of 150/70, 130/70, 115/70 is drawn up. For residential buildings this figure is 105/70 and 95/70. The first indicator shows the supply temperature, and the second - the return temperature. The calculation results are entered into a special table, which shows the temperature at certain points of the heating system, depending on the outside air temperature.

The main factor when calculating the temperature schedule is the outside air temperature. The calculation table must be drawn up so that the maximum values ​​of the coolant temperature in the heating system (graph 95/70) ensure heating of the room. Room temperatures are provided regulatory documents.

heating devices

Temperature heating devices

The main indicator is the temperature of heating devices. The ideal temperature schedule for heating is 90/70ºС. It is impossible to achieve such an indicator, since the temperature inside the room should not be the same. It is determined depending on the purpose of the room.

In accordance with the standards, the temperature in the corner living room is +20ºС, in the rest – +18ºС; in the bathroom – +25ºС. If the outside air temperature is -30ºС, then the indicators increase by 2ºС.

Except Togo, exists norms For others types premises:

• in rooms where children are located – +18ºС to +23ºС;
• children's educational institutions – +21ºС;
• in cultural institutions with mass attendance – +16ºС to +21ºС.

Such an area temperature values designed for all types of premises. It depends on the movements performed inside the room: the more of them, the fewer topics air temperature. For example, in sports facilities people move a lot, so the temperature is only +18ºС.

Room temperature

There are certain factors, from which depends temperature heating devices:

• Outside air temperature;
• Type of heating system and temperature difference: for single pipe system– +105ºС, and for single-pipe – +95ºС. Accordingly, the differences in for the first region are 105/70ºС, and for the second – 95/70ºС;
• Direction of coolant supply to heating devices. At top feed the difference should be 2 ºС, at the bottom – 3ºС;
• Type of heating devices: heat transfer is different, so the temperature curve will be different.

First of all, the coolant temperature depends on the outside air. For example, the temperature outside is 0ºC. At the same time temperature regime in radiators it should be equal to 40-45ºС at the supply, and 38ºС at the return. When the air temperature is below zero, for example -20ºС, these indicators change. IN in this case the supply temperature becomes 77/55ºС. If the temperature reaches -40ºС, then the indicators become standard, that is, +95/105ºС at the supply, and +70ºС at the return.

Additional parameters

In order for a certain temperature of the coolant to reach the consumer, it is necessary to monitor the condition of the outside air. For example, if it is -40ºС, the boiler room should supply hot water with an indicator of +130ºС. Along the way, the coolant loses heat, but the temperature still remains high when it enters the apartments. The optimal value is +95ºС. To do this, an elevator unit is installed in the basements, which serves for mixing hot water from the boiler room and coolant from the return pipeline.

Several institutions are responsible for the heating main. The boiler room monitors the supply of hot coolant to the heating system, and the condition of the pipelines is monitored by city heating networks. The housing office is responsible for the elevator element. Therefore, in order to solve the problem of coolant supply to new home, you need to contact different offices.

Installation of heating devices is carried out in accordance with regulatory documents. If the owner himself replaces the battery, then he is responsible for the operation of the heating system and changes in temperature conditions.

Adjustment methods

Dismantling the elevator unit

If the boiler room is responsible for the parameters of the coolant leaving the warm point, then the housing office workers must be responsible for the temperature inside the room. Many residents complain about the cold in their apartments. This occurs due to a deviation in the temperature graph. In rare cases, it happens that the temperature rises by a certain value.

Heating parameters can be adjusted in three ways:

• Reaming the nozzle.

If the supply and return coolant temperatures are significantly underestimated, then it is necessary to increase the diameter of the elevator nozzle. This way, more liquid will pass through it.

How to do this? To begin with, it overlaps shut-off valves(house valves and taps at the elevator unit). Next, the elevator and nozzle are removed. Then it is drilled out by 0.5-2 mm, depending on how much it is necessary to increase the temperature of the coolant. After these procedures, the elevator is mounted in its original location and put into operation.

To ensure sufficient tightness of the flange connection, it is necessary to replace the paronite gaskets with rubber ones.

• Silence the suction.

In severe cold weather, when the problem of freezing of the heating system in the apartment arises, the nozzle can be completely removed. In this case, the suction may become a jumper. To do this, you need to plug it with a steel pancake 1 mm thick. This process is carried out only in critical situations, since the temperature in pipelines and heating devices will reach 130ºC.

• Adjustment of difference.

In the middle of the heating season, a significant increase in temperature may occur. Therefore, it is necessary to regulate it using a special valve on the elevator. To do this, the supply of hot coolant is switched to the supply pipeline. A pressure gauge is mounted on the return line. Adjustment occurs by closing the valve on the supply pipeline. Next, the valve opens slightly, and the pressure should be monitored using a pressure gauge. If you simply open it, the cheeks will sag. That is, an increase in pressure drop occurs in the return pipeline. Every day the indicator increases by 0.2 atmospheres, and the temperature in the heating system must be constantly monitored.

Heat supply. Video

You can learn how the heat supply of private and apartment buildings works in the video below.

When drawing up a heating temperature schedule, various factors must be taken into account. This list includes not only structural elements building, but the outside temperature, as well as the type of heating system.

To calculate the heat loss of a house, you need to know the thickness of the external walls and the material of the building. Calculation of the surface power of batteries is carried out using the following formula: Rud = P/Fact Where P is the maximum power, W, Fact is the radiator area, cm². Dependence of heat transfer on the outside temperature. According to the data obtained, a temperature regime for heating and a heat transfer graph are drawn up depending on the outside temperature. To change heating parameters in a timely manner, install a heating temperature regulator. This device connects to outdoor and indoor thermometers. Depending on the current indicators, the operation of the boiler or the volume of coolant flow into the radiators is adjusted. The weekly programmer is the optimal heating temperature regulator. With its help, you can automate the operation of the entire system as much as possible.

Heating system temperature graph

Advantages of the regulator:

1. The temperature scheme is strictly maintained.
2. Avoiding overheating of the liquid.
3. Fuel and energy efficiency.
4. The consumer, regardless of the distance, receives heat equally.

Table with temperature graph Operating mode of boilers depends on the weather environment. If we take various objects, for example, a factory premises, multi-storey and private house, all will have an individual thermal diagram.

Blog about energy

Attention

Looking through the statistics of visits to our blog, I noticed that search phrases such as, for example, “what should be the coolant temperature at minus 5 outside?” appear very often. I decided to post the old schedule for the quality regulation of heat supply based on the average daily outside air temperature.

Important

I would like to warn those who, based on these figures, will try to figure out their relationship with housing departments or heating networks: heating schedules for each individual settlement different (I wrote about this in the article regulating the coolant temperature). Heating networks in Ufa (Bashkiria) operate according to this schedule.

I would also like to draw your attention to the fact that regulation occurs based on the average daily outside air temperature, so if, for example, it is minus 15 degrees outside at night and minus 5 during the day, then the coolant temperature will be maintained in accordance with the schedule at minus 10 oC.

Temperature chart

The temperature of the coolant at the entrance to the heating system with high-quality regulation of heat supply depends on the temperature of the outside air, that is, the lower the temperature of the outside air, the higher the temperature the coolant should enter the heating system. The temperature schedule is selected when designing the heating system of a building; the size of the heating devices, the coolant flow in the system, and, consequently, the diameter of the distribution pipelines depend on it.
To indicate the temperature graph, two numbers are used, for example, 90-70°C - this means that at the estimated outdoor temperature (for Kyiv -22°C), to create a comfortable indoor air temperature (for housing 20°C), in The heating system must enter the coolant (water) at a temperature of 90°C, and leave it at a temperature of 70°C.

Heating system temperature graph 95 70 snip table

Info

Analysis and adjustment of operating modes is carried out using a temperature diagram. For example, the return of liquid with an elevated temperature will indicate high coolant costs.

Underestimated data will be considered a consumption deficit. Previously, for 10-story buildings, a scheme with calculated data of 95-70°C was introduced.

The buildings above had their own chart of 105-70°C. Modern new buildings may have a different layout, at the discretion of the designer. More often, there are diagrams of 90-70°C, and maybe 80-60°C. Temperature graph 95-70: Temperature graph 95-70 How is it calculated? A control method is selected, then a calculation is made. The calculated winter and reverse order of water supply, the amount of outside air, and the order at the break point of the diagram are taken into account. There are two diagrams: one of them considers only heating, the second considers heating with hot water consumption.

Heating temperature chart

In this case, the degree of air heating in residential premises should be at +22°C. For non-residential residents this figure is slightly lower - +16°C. For centralized system drawing up a correct temperature schedule for the heating boiler room is required to ensure optimal comfortable temperature in apartments.

The main problem is the lack feedback– it is impossible to regulate the coolant parameters depending on the degree of air heating in each apartment. That is why a temperature graph of the heating system is drawn up. A copy of the heating schedule can be requested from Management Company. With its help you can control the quality of the services provided. Autonomous heating Thermostat Make similar calculations for autonomous systems Heating a private home is often not necessary.

Temperature graph of sources and heating networks

The dependency schedule may vary. A specific diagram has a dependency on:

1. Technical and economic indicators.
2. CHP or boiler room equipment.
3. Climate.

High coolant values ​​provide the consumer with great thermal energy. Below is an example of a diagram, where T1 is the temperature of the coolant, Tnv is the outside air: A diagram of the returned coolant is also used.

A boiler house or thermal power plant can estimate the efficiency of the source using this scheme. It is considered high when the returned liquid arrives chilled. The stability of the circuit depends on the design values ​​of fluid flow high-rise buildings. If the flow through the heating circuit increases, the water will return uncooled, as the flow rate will increase. And vice versa, with minimal flow, return water will be sufficiently cooled.

The supplier's interest, of course, is in the supply of return water in a cooled state. But there are certain limits for reducing consumption, since a decrease leads to loss of heat.

The consumer’s internal temperature in the apartment will begin to drop, which will lead to a violation building codes and the discomfort of ordinary people. What does it depend on? The temperature curve depends on two quantities: outside air and coolant. Frosty weather leads to an increase in coolant temperature. When designing a central source, the size of the equipment, building and pipe size are taken into account. The temperature leaving the boiler room is 90 degrees, so that at minus 23°C, the apartments are warm and have a value of 22°C. Then the return water returns to 70 degrees. Such norms correspond to normal and comfortable living in the house.

Temperature graph of the heating system - calculation procedure and ready-made tables

For networks operating according to temperature schedules of 95-70°C and 105-70°C (columns 5 and 6 of the table), the water temperature in the return pipeline of heating systems is determined according to column 7 of the table. For consumers connected via an independent connection scheme, the water temperature in the forward pipeline is determined according to column 4 of the table, and in the return pipeline according to column 8 of the table.

The temperature schedule for regulating the heat load is developed from the conditions of daily supply of thermal energy for heating, ensuring the need of buildings for thermal energy depending on the temperature of the outside air, in order to ensure the temperature in the premises is constant at a level of at least 18 degrees, as well as covering the heat load of hot water supply with the provision DHW temperature in places of water supply not lower than + 60°C, in accordance with the requirements of SanPin 2.1.4.2496-09 “Drinking water.

Build for closed system heat supply schedule for central quality regulation of heat supply based on the combined load of heating and hot water supply (increased or adjusted temperature schedule).

Accept the calculated temperature of the network water in the supply line t 1 = 130 0 C, in the return line t 2 = 70 0 C, after the elevator t 3 = 95 0 C. Design temperature outdoor air for heating design tnro = -31 0 C. Design indoor air temperature tb = 18 0 C. Calculated heat flows accept the same. Hot water temperature in hot water supply systems tgv = 60 0 C, temperature cold water t c = 5 0 C. Balance coefficient for hot water supply load a b = 1.2. The connection diagram for water heaters of hot water supply systems is two-stage sequential.

Solution. Let us first carry out the calculation and construction of a heating and domestic temperature graph with the temperature of the network water in the supply pipeline for the break point = 70 0 C. Values ​​of network water temperatures for heating systems t 01 ; t 02 ; t 03 will be determined using calculated dependencies (13), (14), (15) for outside air temperatures t n = +8; 0; -10; -23; -31 0 C

Let us determine, using formulas (16), (17), (18), the values ​​of quantities

For t n = +8 0С values t 01, t 02 ,t 03 will accordingly be:

Calculations of network water temperatures are carried out similarly for other values. t n. Using the calculated data and accepting minimum temperature network water in the supply pipeline = 70 0 C, let's build a heating and household temperature graph (see Fig. 4). The break point of the temperature graph will correspond to the network water temperatures = 70 0 C, = 44.9 0 C, = 55.3 0 C, outdoor air temperature = -2.5 0 C. We reduce the obtained values ​​of the network water temperatures for the heating and domestic schedule in Table 4. Next, we proceed to the calculation of the increased temperature schedule. Having specified the value of underheating D t n = 7 0 C we determine the temperature of the heated tap water after the first stage water heater

Let us determine the balance load of hot water supply using formula (19)

Using formula (20), we determine the total temperature difference of the network water d in both stages of water heaters

Using formula (21), we determine the temperature difference of the network water in the first stage water heater for the range of outdoor air temperatures from t n = +8 0 C to t" n = -2.5 0 C

For the specified range of outdoor air temperatures, we determine the temperature difference of the network water in the second stage of the water heater

Let us determine using formulas (22) and (25) the values ​​of quantities d 2 and d 1 for outdoor temperature range t n from t" n = -2.5 0 C before t 0 = -31 0 C. So, for t n = -10 0 C these values ​​will be:

Let us similarly perform calculations of the quantities d 2 and d 1 for values t n = -23 0 C and t n = –31 0 C. The temperatures of the network water in both the supply and return pipelines for an increased temperature curve will be determined using formulas (24) and (26).

Yes, for t n = +8 0 C and t n = -2.5 0 C these values ​​will be

For t n = -10 0 C

Let us similarly perform calculations for the values t n = -23 0 C and -31 0 C. Obtained values d 2, d 1, , we summarize in table 4.

To plot the temperature of the network water in the return pipeline after the air heaters of ventilation systems in the range of outside air temperatures t n = +8 ¸ -2.5 0 C we use formula (32)

Let's determine the value t 2v for t n = +8 0 C. Let us first set the value 0 C. Let us determine the temperature pressure in the heater and, accordingly, for t n = +8 0 C and t n = -2.5 0 C

Let's calculate the left and right sides of the equation

Left side

Right side

Since numerical values the right and left sides of the equation are close in value (within 3%), we will accept the value as final.

For ventilation systems with air recirculation, we determine, using formula (34), the temperature of the network water after the air heaters t 2v for t n = t nro = -31 0 C.

Here the values ​​of D t ; t ; t correspond t n = t v = -23 0 C. Since this expression is solved by the selection method, we first set the value t 2v = 51 0 C. Determine the values ​​of D t k and D t

Since the left side of the expression is close in value to the right (0.99"1), the previously accepted value t 2v = 51 0 C will be considered final. Using the data in Table 4, we will construct heating-domestic and elevated temperature control schedules (see Fig. 4).

Table 4 - Calculation of temperature control schedules for a closed heat supply system.

t N	t 10	t 20	t 30	d 1	d 2	t 1P	t 2P	t 2V
+8	70	44,9	55,3	5,9	8,5	75,9	36,4	17
-2,5	70	44,9	55,3	5,9	8,5	75,9	36,4	44,9
-10	90,2	5205	64,3	4,2	10,2	94,4	42,3	52,5
-23	113,7	63,5	84,4	1,8	12,5	115,6	51	63,5
-31	130	70	95	0,4	14	130,4	56	51

Fig.4. Temperature control charts for a closed heating system (¾ heating and domestic; --- increased)

Construct an adjusted (increased) central quality regulation schedule for an open heat supply system. Accept the balance coefficient a b = 1.1. Accept the minimum temperature of the network water in the supply pipeline for the break point of the temperature graph of 0 C. Take the remaining initial data from the previous part.

Solution. First, we build graphs of temperatures , , , using calculations using formulas (13); (14); (15). Next, we will construct a heating and household graph, the break point of which corresponds to the temperature values ​​of the network water 0 C; 0 C; 0 C, and the outside air temperature is 0 C. Next, we proceed to calculate the adjusted schedule. Let's determine the balance load of hot water supply

Let us determine the ratio of the balance load for hot water supply to design load for heating

For a range of outdoor temperatures t n = +8 0 C; -10 0 C; -25 0 C; -31 0 C, we determine the relative heat consumption for heating using formula (29)`; For example for t n = -10 will be:

Then, taking the values ​​​​known from the previous part t c ; t h ; q; Dt we determine using formula (30) for each value t n relative costs of network water for heating.

For example, for t n = -10 0 C will be:

Let us perform calculations similarly for other values. t n.

Supply water temperature t 1p and reverse t 2p pipelines for the adjusted schedule will be determined using formulas (27) and (28).

Yes, for t n = -10 0 C we get

Let's do the calculations t 1p and t 2p and for other values t n. Let us determine using the calculated dependencies (32) and (34) the temperature of the network water t 2v after heaters of ventilation systems for t n = +8 0 C and t n = -31 0 C (in the presence of recirculation). When value t n = +8 0 C let’s first set the value t 2v = 23 0 C.

Let's define the values Dt to and Dt To

;

Since the numerical values ​​of the left and right sides of the equation are close, the previously accepted value t 2v = 23 0 C, we will consider it final. Let us also define the values t 2v at t n = t 0 = -31 0 C. Let us first set the value t 2v = 47 0 C

Let's calculate the values ​​of D t to and

We summarize the obtained values ​​of the calculated values ​​in Table 3.5

Table 5 - Calculation of the increased (adjusted) schedule for an open heat supply system.

t n	t 10	t 20	t 30	`Q 0	`G 0	t 1p	t 2p	t 2v
+8	60	40,4	48,6	0,2	0,65	64	39,3	23
1,9	60	40,4	48,6	0,33	0,8	64	39,3	40,4
-10	90.2	52.5	64.3	0,59	0,95	87.8	51.8	52.5
-23	113.7	63.5	84.4	0,84	1,02	113	63,6	63.5
-31	130	70	95	1	1,04	130	70	51

Using the data from Table 5, we will construct heating and domestic, as well as increased temperature schedules for network water.

Fig.5 Heating - household ( ) and increased (----) schedules of network water temperatures for an open heating system

Hydraulic calculation of main heat pipelines of a two-pipe water heating network of a closed heat supply system.

The design diagram of the heating network from the heat source (IT) to the city blocks (CB) is shown in Fig. 6. To compensate for temperature deformations, provide gland compensators. Take the specific pressure loss along the main line in the amount of 30-80 Pa/m.

Fig.6. Design diagram of the main heating network.

Solution. The calculation will be performed for the supply pipeline. Let us take the longest and busiest branch of the heating network from IT to KV 4 (sections 1,2,3) as the main line and proceed to its calculation. According to the hydraulic calculation tables given in the literature, as well as in Appendix No. 12 teaching aid, based on known coolant flow rates, focusing on specific pressure losses R in the range from 30 to 80 Pa/m, we will determine the pipeline diameters for sections 1, 2, 3 d n xS, mm, actual specific pressure loss R, Pa/m, water speed V, m/s.

Based on the known diameters in sections of the main highway, we determine the sum of the local resistance coefficients S x and their equivalent lengths L e. Thus, in section 1 there is a head valve ( x= 0.5), tee for passage when dividing the flow ( x= 1.0), Number of stuffing box compensators ( x= 0.3) on the section will be determined depending on the length of the section L and the maximum permissible distance between fixed supports l. According to Appendix No. 17 of the training manual for D y = 600 mm this distance is 160 meters. Therefore, in section 1 with a length of 400 m, three stuffing box expansion joints should be provided. Sum of local resistance coefficients S x in this area will be

S x= 0.5+1.0 + 3 × 0.3 = 2.4

According to Appendix No. 14 of the textbook (if TO e = 0.0005m) equivalent length l uh for x= 1.0 equals 32.9 m. Equivalent section length L uh will be

L e = l e × S x= 32.9 × 2.4 = 79 m

L n = L+ L e = 400 + 79 = 479 m

Then we determine the pressure loss DP in section 1

D P= R×L n = 42 × 479 = 20118 Pa

Similarly, we will perform a hydraulic calculation of sections 2 and 3 of the main highway (see Table 6 and Table 7).

Next, we proceed to the calculation of branches. Based on the principle of linking pressure loss D P from the flow division point to the end points (EP) for different branches of the system must be equal to each other. Therefore, when hydraulically calculating branches, it is necessary to strive to fulfill following conditions:

D P 4+5 = D P 2+3 ; D P 6 = D P 5 ; D P 7 = D P 3

Based on these conditions, we will find the approximate specific pressure losses for the branches. So, for a branch with sections 4 and 5 we get

Coefficient a, taking into account the share of pressure losses due to local resistance, will be determined by the formula

Then Pa/m

Focusing on R= 69 Pa/m we will determine pipeline diameters and specific pressure losses using hydraulic calculation tables R, speed V, pressure loss D R in sections 4 and 5. We will similarly perform the calculation of branches 6 and 7, having previously determined the approximate values ​​for them R.

Pa/m

Pa/m

Table 6 - Calculation of equivalent lengths of local resistances

Plot number	dн x S, mm	L, m	Type of local resistance	x	Qty	åx	l e, m	Lе,m
1	630x10	400	1. valve 2. stuffing box compensator	0.5 0.3 1.0	1 3 1	2,4	32,9	79
2	480x10	750	1. sudden contraction 2. stuffing box compensator 3. tee for passage when dividing the flow	0.5 0.3 1.0	1 6 1	3,3	23,4	77
3	426x10	600	1. sudden contraction 2. stuffing box compensator 3. valve	0.5 0.3 0.5	1 4 1	2,2	20,2	44,4
4	426x10	500	1. branch tee 2. valve 3. stuffing box compensator 4. tee for passage	1.5 0.5 0.3 1.0	1 1 4 1	4.2	20.2	85
5	325x8	400	1. stuffing box compensator 2. valve	0.3 0.5	4 1	1.7	14	24
6	325x8	300	1. branch tee 2. stuffing box compensator 3. valve	1.5 0.5 0.5	1 2 2	3.5	14	49
7	325x8	200	1. branch tee when dividing the flow 2.valve 3. stuffing box compensator	1.5 0.5 0.3	1 2 2	3.1	14	44

Table 7 - Hydraulic calculation of main pipelines

Plot number	G, t/h	Length, m	dнхs, mm	V, m/s	R, Pa/m	DP, Pa	åDP, Pa
L	Le	Lп
1 2 3	1700 950 500	400 750 600	79 77 44	479 827 644	630x10 480x10 426x10	1.65 1.6 1.35	42 55 45	20118 45485 28980	94583 74465 28980
4 5	750 350	500 400	85 24	585 424	426x10 325x8	1.68 1.35	70 64	40950 27136	68086 27136
6	400	300	49	349	325x8	1.55	83	28967	28967
7	450	200	44	244	325x8	1.75	105	25620	25620

Let us determine the discrepancy of pressure losses on the branches. The discrepancy on the branch with sections 4 and 5 will be:

The discrepancy on branch 6 will be:

The discrepancy on branch 7 will be.

Looking through the statistics of visits to our blog, I noticed that search phrases such as, for example, very often appear “What should the coolant temperature be at minus 5 outside?”. I decided to post the old one schedule for qualitative regulation of heat supply based on average daily outside air temperature. I would like to warn those who, based on these figures, will try to figure out the relationship with housing departments or heating networks: heating schedules for each individual settlement are different (I wrote about this in the article). Heating networks in Ufa (Bashkiria) operate according to this schedule.

I also want to draw attention to the fact that regulation occurs according to average daily outside air temperature, so if, for example, outside at night minus 15 degrees, and during the day minus 5, then the coolant temperature will be maintained in accordance with the schedule at minus 10 o C.

Typically, the following temperature charts are used: 150/70 , 130/70 , 115/70 , 105/70 , 95/70 . The schedule is selected depending on specific local conditions. House heating systems operate according to schedules 105/70 and 95/70. Main heating networks operate according to schedules 150, 130 and 115/70.

Let's look at an example of how to use a chart. Let's say the temperature outside is minus 10 degrees. Heat networks work according to temperature schedule 130/70 , which means when -10 o C the temperature of the coolant in the supply pipeline of the heating network should be 85,6 degrees, in the supply pipe of the heating system - 70.8 o C with a 105/70 schedule or 65.3 o C with a 95/70 schedule. The water temperature after the heating system should be 51,7 about S.

As a rule, the temperature values ​​in the supply pipeline of heating networks are rounded when assigned to a heat source. For example, according to the schedule it should be 85.6 o C, but at a thermal power plant or boiler house it is set to 87 degrees.

Temperature outdoor air Tnv, o S	Temperature of network water in the supply pipeline T1, o C			Water temperature in the heating system supply pipe T3, o C		Water temperature after the heating system T2, o C
	150	130	115	105	95
8	53,2	50,2	46,4	43,4	41,2	35,8
7	55,7	52,3	48,2	45,0	42,7	36,8
6	58,1	54,4	50,0	46,6	44,1	37,7
5	60,5	56,5	51,8	48,2	45,5	38,7
4	62,9	58,5	53,5	49,8	46,9	39,6
3	65,3	60,5	55,3	51,4	48,3	40,6
2	67,7	62,6	57,0	52,9	49,7	41,5
1	70,0	64,5	58,8	54,5	51,0	42,4
0	72,4	66,5	60,5	56,0	52,4	43,3
-1	74,7	68,5	62,2	57,5	53,7	44,2
-2	77,0	70,4	63,8	59,0	55,0	45,0
-3	79,3	72,4	65,5	60,5	56,3	45,9
-4	81,6	74,3	67,2	62,0	57,6	46,7
-5	83,9	76,2	68,8	63,5	58,9	47,6
-6	86,2	78,1	70,4	65,0	60,2	48,4
-7	88,5	80,0	72,1	66,4	61,5	49,2
-8	90,8	81,9	73,7	67,9	62,8	50,1
-9	93,0	83,8	75,3	69,3	64,0	50,9
-10	95,3	85,6	76,9	70,8	65,3	51,7
-11	97,6	87,5	78,5	72,2	66,6	52,5
-12	99,8	89,3	80,1	73,6	67,8	53,3
-13	102,0	91,2	81,7	75,0	69,0	54,0
-14	104,3	93,0	83,3	76,4	70,3	54,8
-15	106,5	94,8	84,8	77,9	71,5	55,6
-16	108,7	96,6	86,4	79,3	72,7	56,3
-17	110,9	98,4	87,9	80,7	73,9	57,1
-18	113,1	100,2	89,5	82,0	75,1	57,9
-19	115,3	102,0	91,0	83,4	76,3	58,6
-20	117,5	103,8	92,6	84,8	77,5	59,4
-21	119,7	105,6	94,1	86,2	78,7	60,1
-22	121,9	107,4	95,6	87,6	79,9	60,8
-23	124,1	109,2	97,1	88,9	81,1	61,6
-24	126,3	110,9	98,6	90,3	82,3	62,3
-25	128,5	112,7	100,2	91,6	83,5	63,0
-26	130,6	114,4	101,7	93,0	84,6	63,7
-27	132,8	116,2	103,2	94,3	85,8	64,4
-28	135,0	117,9	104,7	95,7	87,0	65,1
-29	137,1	119,7	106,1	97,0	88,1	65,8
-30	139,3	121,4	107,6	98,4	89,3	66,5
-31	141,4	123,1	109,1	99,7	90,4	67,2
-32	143,6	124,9	110,6	101,0	94,6	67,9
-33	145,7	126,6	112,1	102,4	92,7	68,6
-34	147,9	128,3	113,5	103,7	93,9	69,3
-35	150,0	130,0	115,0	105,0	95,0	70,0

Please do not rely on the diagram at the beginning of the post - it does not correspond to the data from the table.

Temperature graph calculation

The method for calculating the temperature graph is described in the reference book (Chapter 4, paragraph 4.4, p. 153).

This is quite labor intensive and long process, since for each outside air temperature several values ​​need to be counted: T 1, T 3, T 2, etc.

To our joy, we have a computer and a spreadsheet processor MS Excel. A work colleague shared with me a ready-made table for calculating the temperature graph. It was made at one time by his wife, who worked as an engineer for a group of modes in thermal networks.

In order for Excel to calculate and build a graph, you just need to enter a few initial values:

• design temperature in the supply pipeline of the heating network T 1
• design temperature in the return pipeline of the heating network T 2
• design temperature in the heating system supply pipe T 3
• Outdoor temperature T n.v.
• Indoor temperature T v.p.
• coefficient " n"(it is, as a rule, unchanged and equal to 0.25)
• Minimum and maximum cut of the temperature graph Cut min, Cut max.

All. nothing more is required from you. The calculation results will be in the first table of the sheet. It is highlighted with a bold frame.

The charts will also adjust to the new values.

The table also calculates the temperature of direct network water taking into account wind speed.