We determine the discrepancy of pressure losses in two directions through the near and far risers using the formula:
where ΣΔp1, ΣΔp2 are, respectively, pressure losses when calculating directions through the far and near risers.
5. Calculation of heat losses by pipelines of the hot water supply system
Heat losses DQ, (W), in the calculated section of the supply pipeline or riser are determined according to the standard specific losses heat or by calculation using the formula:
where K is the heat transfer coefficient insulated pipeline, K=11.6 W/(m2-°C); tгср - average water temperature in the system, tгср,=(tн +tк)/2, °С; tн, - temperature at the outlet of the heater (temperature of hot water at the entrance to the building), °C; tk is the temperature at the most distant water tap, °C; h- Thermal efficiency insulation (0.6); / - length of the pipeline section, m; dH- outside diameter pipeline, m; t0 - temperature environment, °C.
The water temperature at the most remote water tap tk should be taken 5 °C lower than the water temperature at the entrance to the building or at the outlet of the heater.
The ambient temperature t0 when laying pipelines in furrows, vertical channels, communication shafts and sanitary cabin shafts should be taken equal to 23 ° C, in bathrooms - 25 ° C, in kitchens and toilet rooms of residential buildings, dormitories and hotels - 21 ° WITH .
Heating of bathrooms is carried out by heated towel rails, therefore, to the heat loss of the riser, heat loss from heated towel rails is added in the amount of 100p (W), where 100 W is the average heat transfer by one heated towel rail, n is the number of heated towel rails connected to the riser.
When determining circulation water flow rates, heat losses through circulation pipelines are not taken into account. However, when calculating hot water supply systems with heated towel rails on circulation risers, it is advisable to add the heat transfer of heated towel rails to the amount of heat loss by the supply heat pipes. This increases the circulation flow of water, improves the heating of heated towel rails and heating of bathrooms. The calculation results are entered into the table.
|
(tсрг-t0), °С |
Heat loss, W |
Notes |
||||||
|
q at a length of 1 m |
ΔQ on the site |
|||||||
|
Highway |
||||||||
|
ΔQ=1622.697W |
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|
Total riser losses ΔQ=459.3922 W |
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|
Total losses of the riser, including heated towel rails ΔQ=1622.284 W |
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|
Total riser losses ΔQ=459.3922 W |
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To maintain a constant temperature at water taps in residential and public buildings, hot water is circulated between the tap points and the heat generator. The amount of circulation flow is determined during the thermal calculation of the central heating system network. Depending on the magnitude of the circulation flow rate in the design sections, the diameters of the circulation pipelines are assigned. The amount of heat loss by the central heating system is determined as the sum of heat losses in network sections according to the formula
where is the specific heat loss of 1 running meter of pipeline.
When designing central heating systems with sectional units, heat loss of 1 linear meter of a pipeline can be assumed, depending on the type of pipeline, location and method of its installation. The heat loss of 1 running meter of pipes is given in Appendix 2. Heat loss by insulated pipelines of a quarterly network at different conditions gaskets are given in Appendix 3.
The circulating flow of hot water, according to clause 8.2, in the system is determined by the formula:
, l/s,
where Q ht – heat loss by hot water supply pipelines, kW;
t – temperature difference in the supply pipelines of the system from the water heater to the most remote water distribution point, С;
– circulation misregulation coefficient.
The values of Q ht and are taken at the same resistance of sectional units
Dt = 8.5С and b = 1.3.
In accordance with the recommendations of clause 9.16, we provide thermal insulation supply and circulation pipelines, including risers, except for connections to appliances and heated towel rails. As thermal insulation, we use molded mineral wool cylinders produced by Rokwool Russia.
Heat losses are determined for all supply pipelines of the hot water supply system. The calculation is carried out in the form of table 4. Specific heat losses are taken according to appendices 2 and 3.
|
Table 4. Calculation of heat loss through supply pipelines |
|||||||||
|
Pipe diameter, mm |
Number of risers or towel dryers |
Riser or pipeline length, m |
Total pipe length, m |
Specific heat loss, W |
Heat loss of risers, W |
Heat loss of main pipelines, W |
|||
|
Water risers |
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|
Heated towel rails |
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|
Main pipes in the basement |
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|
Total for one house: | |||||||||
|
Total for two houses: | |||||||||
|
Main pipes in the channel |
|||||||||
|
Total heat loss: Q ht = 29342 + 3248 = 32590 W = 32.59 kW |
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3.3. Hydraulic calculation of supply pipelines when supplying circulation calculations
Hydraulic calculations of supply pipelines for passing circulation flows through them are carried out in the absence of water intake. The amount of circulation flow is determined by the formula
, l/s.
For sectional units with the same resistance, we take Dt = 8.5°C and b = 1.3.
l/s, 
l/s*.
The circulation flow from the water heater is supplied through supply pipelines and water risers and discharged through circulation risers and circulation main pipelines to the water heater. Since the risers are the same, in order to replenish heat loss by pipes, the same circulation flow must pass through each water riser.
We determine the amount of circulation flow passing through the riser:
, l/s,
where n st is the number of water risers in a residential building.
Hydraulic calculations of supply and circulation pipelines are carried out according to the calculated direction relative to the dictating point. Specific pressure losses are taken according to Appendix 1. The calculation results are given in Table 5.
|
Table 5. Hydraulic calculation of supply pipelines for passage |
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|
circulation flow |
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|
Plot number |
Pipe diameter, mm |
Circulation flow, l/s |
Speed, m/s |
Pressure loss, mm |
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|
Location on |
H= il(1+Kl) |
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|
∑h l = 970.14 mm = | |||||||||
On payment of thermal energy during the inter-heating period
In the summer, in the receipts of St. Petersburg residents for housing public utilities the line “thermal energy loss in hot water” appeared. The wording of the position may differ, but the essence is the same - with the transition to seasonal heating payments, it became necessary to pay for the consumption of thermal energy associated with heat transfer through risers and heated towel rails. For example, in a letter from the Housing Committee of St. Petersburg, an explanation is given “about the procedure for paying for thermal energy for the circulation of hot water supply through heated towel rails.” The problem is that, in accordance with the existing legislation and regulatory framework, tariffs for thermal energy, including for hot water supply needs, can only be set in rubles/Gcal. Heat supply organizations (SUE "TEK SPb", TGK) do just that, issuing bills for heat energy according to the readings of metering units in Gcal at established tariffs (prices). Residents are charged for hot water supply according to indications apartment meters or according to consumption standards in cubic meters, which leads to a significant difference between the cost of thermal energy and the cost of hot water. This difference can be more than 30%. But what was it like before? During the period when the heating fee was calculated, the additional consumption of thermal energy for risers and heated towel rails was taken into account in the heating fee, the so-called ODN. But according to the Rules approved by the Decree of the Government of the Russian Federation dated April 16, 2013 No. 344, the heating fee for ODN has been cancelled. In accordance with the Rules, the calculation of the amount of payment for utility services is made based on the actual volumes of consumption of utility resources in accordance with the readings of common house meters. From which it follows that all thermal energy must be paid in full. As they say, bills have to be paid. The rules developed by the Ministry of Regional Development do not provide for the procedure for paying these costs. Currently, the Ministry of Regional Development of the Russian Federation is developing appropriate changes related to the specified heat consumption to include them in the Decrees of the Government of the Russian Federation No. 306 and No. 354. Before introducing these changes, the Tariff Committee of St. Petersburg recommended that amounts exceeding the consumption of thermal energy for hot water supply be attributed to design consumption 0.06 Gcal/cubic. m for the article “thermal energy for heating water for hot water supply.” (Letter No. 01-14-1573/13-0-1 dated June 17, 2013) Thus, the line that appears in the receipt is legal and fully complies with the requirements of Article 7 and Article 39 of the Housing Code of the Russian Federation.
This is published on the website of the Criminal Code.
SNiP 2.04.01-85*
Building codes and rules
Internal water supply and building drainage.
Internal cold and hot water supply systems
WATER PIPES
8. Calculation of the hot water supply network
8.1. Hydraulic calculations of hot water supply systems should be made based on the estimated hot water flow
Taking into account the circulation flow, l/s, determined by the formula
(14)
where is the coefficient accepted: for water heaters and the initial sections of systems up to the first water riser according to the mandatory Appendix 5;
for other sections of the network - equal to 0.
8.2. The circulating flow rate of hot water in the system, l/s, should be determined by the formula
(15)
where is the circulation misregulation coefficient;
Heat loss from hot water supply pipelines, kW;
Temperature difference in the supply pipelines of the system from the water heater to the most distant water supply point, °C.
Values and depending on the hot water supply scheme should be taken:
for systems that do not provide for water circulation through water risers, the value should be determined from the supply and distribution pipelines at = 10°C and = 1;
for systems in which water circulation is provided through water risers with variable resistance of the circulation risers, the value should be determined from the supply distribution pipelines and water risers at = 10°C and = 1; with the same resistance of sectional units or risers, the value should be determined by water risers at = 8.5 ° C and = 1.3;
for a water riser or sectional unit, heat loss should be determined from the supply pipelines, including the ring jumper, taking = 8.5°C and = 1.
8.3. Pressure losses in sections of pipelines of hot water supply systems should be determined:
for systems where it is not necessary to take into account the overgrowing of pipes - in accordance with clause 7.7;
for systems taking into account pipe overgrowth - according to the formula
where i is the specific pressure loss, taken in accordance with the recommended appendix 6;
Coefficient taking into account pressure loss in local resistance, the values of which should be taken:
0.2 - for supply and circulation distribution pipelines;
0.5 - for pipelines within heating points, as well as for pipelines of water risers with heated towel rails;
0.1 - for pipelines of water risers without heated towel rails and circulation risers.
8.4. The speed of water movement should be taken in accordance with clause 7.6.
8.5. The pressure loss in the supply and circulation pipelines from the water heater to the most remote water-drawn or circulation risers of each branch of the system should not differ for different branches by more than 10%.
8.6. If it is impossible to coordinate the pressures in the pipeline network of hot water supply systems by appropriately selecting pipe diameters, it is necessary to install temperature regulators or diaphragms on the circulation pipeline of the system.
The diaphragm diameter should not be taken less than 10 mm. If, according to calculations, the diameter of the diaphragms must be less than 10 mm, then it is permissible to install taps instead of the diaphragm to regulate the pressure.
It is recommended to determine the diameter of the holes of the control diaphragms using the formula
(17)
8.7. In systems with the same resistance of sectional units or risers, the total pressure loss along the supply and circulation pipelines between the first and last risers at circulation flow rates should be 1.6 times higher than the pressure loss in the sectional unit or riser with circulation deregulation = 1.3.
The diameters of the pipelines of the circulation risers should be determined in accordance with the requirements of clause 7.6, provided that at circulation flow rates in the risers or sectional units determined in accordance with clause 8.2, the pressure losses between the points of their connection to the distribution supply and collection circulation pipelines do not differ more than 10%.
8.8. In hot water supply systems connected to closed heating networks, the pressure loss in sectional units at the calculated circulation flow rate should be taken as 0.03-0.06 MPa (0.3-0.6 kgf/sq.cm).
8.9. In hot water supply systems with direct water withdrawal from the pipelines of the heating network, the pressure loss in the pipeline network should be determined taking into account the pressure in return pipeline heating network.
The pressure loss in the circulation ring of the system pipelines at circulation flow should, as a rule, not exceed 0.02 MPa (0.2 kgf/sq.cm).
8.10. In showers with more than three shower screens, the distribution pipeline should, as a rule, be provided in a loop.
One-way supply of hot water may be provided for manifold distribution.
8.11. When zoning hot water supply systems, it is allowed to provide for the possibility of organizing natural circulation of hot water in the upper zone at night.
A new column has appeared in receipts for utility services - hot water supply. It caused confusion among users, since not everyone understands what it is and why it is necessary to make payments on this line. There are also apartment owners who cross out the box. This entails the accumulation of debt, penalties, fines and even litigation. In order not to take matters to extreme measures, you need to know what DHW is, DHW heat energy and why you need to pay for these indicators.
What is DHW on the receipt?
DHW - this designation stands for hot water supply. Its purpose is to provide apartments in apartment buildings and other residential premises hot water with an acceptable temperature, but hot water supply is not the hot water itself, but the thermal energy that is spent on heating the water to an acceptable temperature.
Experts divide hot water supply systems into two types:
- Central system. Here the water is heated at a heating station. After this, it is distributed to apartments in multi-apartment buildings.
- Autonomous system. It is usually used in private homes. The principle of operation is the same as in the central system, but here the water is heated in a boiler or boiler and is used only for the needs of one specific room.
Both systems have the same goal - to provide home owners with hot water. Apartment buildings usually use a central system, but many users install a boiler in case hot water will be turned off, as has happened more than once in practice. An autonomous system is installed where there is no way to connect to central water supply. Only those consumers who use the central heating system pay for hot water supply. Autonomous circuit users pay utility resources, which are spent to heat the coolant - gas or electricity.
Important! Another column in the receipt related to DHW is DHW at one unit. Decoding ODN - general house needs. This means that the DHW column on one unit is the expenditure of energy on heating water used for the general needs of all residents of an apartment building.
These include:
- technical work that is performed before the heating season;
- pressure testing of the heating system carried out after repair;
- repair work;
- heating of common areas.
Hot water law
The law on hot water supply was adopted in 2013. Government Resolution No. 406 states that users central system heating companies are required to pay according to a two-part tariff. This suggests that the tariff was divided into two elements:
- thermal energy;
- cold water.
This is how DHW appeared on the receipt, that is, the thermal energy spent on heating cold water. Housing and communal services specialists came to the conclusion that risers and heated towel rails, which are connected to the hot water supply circuit, consume thermal energy for heating non-residential premises. Until 2013, this energy was not taken into account in receipts, and consumers used it free of charge for decades, since outside heating season The heating of the air in the bathroom continued. Based on this, officials divided the tariff into two components, and now citizens have to pay for hot water.
Water heating equipment
The equipment that heats the liquid is a water heater. Its breakdown does not affect the hot water tariff, but users are required to pay the cost of repairing the equipment, since water heaters are part of the property of homeowners in apartment building. The corresponding amount will appear in the receipt for the maintenance and repair of the property.
Important! This payment should be carefully considered by the owners of those apartments who do not use hot water, since their housing has a autonomous system heating. Housing and communal services specialists do not always pay attention to this, simply distributing the amount for water heater repairs among all citizens.
As a result, these apartment owners have to pay for equipment they did not use. If you discover an increase in the tariff for repairs and maintenance of property, you need to find out what this is connected with and contact management company for recalculation if the payment is calculated incorrectly.
Thermal energy component
What is this - a coolant component? This is heating cold water. The thermal energy component does not have a meter installed, unlike hot water. For this reason, it is impossible to calculate this indicator using a counter. How, in this case, is the thermal energy for hot water calculated? When calculating the payment, the following points are taken into account:
- tariff set for hot water supply;
- expenses spent on maintaining the system;
- cost of heat loss in the circuit;
- costs spent on coolant transfer.
Important! The cost of hot water is calculated taking into account the volume of water consumed, which is measured in 1 cubic meter.
The size of the energy fee is usually calculated based on the readings of the common hot water meter and the amount of energy in the hot water. Energy is also calculated for each individual apartment. To do this, water consumption data is taken, which is learned from the meter readings, and multiplied by specific consumption thermal energy. The received data is multiplied by the tariff. This figure is the required contribution, which is indicated on the receipt.
How to make your own calculation
Not all users trust the settlement center, which is why the question arises of how to calculate cost of hot water supply on one's own. The resulting figure is compared with the amount on the receipt and on the basis of this a conclusion is made about the correctness of the charges.
To calculate the cost of hot water supply, you need to know the tariff for thermal energy. The amount is also affected by the presence or absence of a meter. If there is one, then readings are taken from the meter. In the absence of a meter, the standard for the consumption of thermal energy used to heat water is taken. This standard indicator is established by an energy saving organization.
If in multi-storey building an energy consumption meter is installed and the housing has a hot water meter, then the amount for hot water supply is calculated based on general house metering data and the subsequent proportional distribution of the coolant among apartments. If there is no meter, the rate of energy consumption per 1 cubic meter of water and the readings of individual meters are taken.
Complaint due to incorrect calculation of receipt
If after self-calculation If there is a difference in the amount of contributions for hot water supply, you must contact the management company for clarification. If the organization's employees refuse to provide explanations on this matter, a written complaint must be submitted. Company employees have no right to ignore it. The response must be received within 13 working days.
Important! If no response is received or it is not clear from it why this situation arose, then the citizen has the right to file a claim with the prosecutor’s office or a statement of claim in court. The authority will consider the case and make an appropriate objective decision. You can also contact organizations that control the activities of the management company. Here the subscriber's complaint will be considered and an appropriate decision will be made.
Electricity used to heat water is not a free service. Payment for it is charged on the basis of the Housing Code Russian Federation. Each citizen can independently calculate the amount of this payment and compare the data obtained with the amount on the receipt. If any inaccuracy occurs, you should contact the management company. In this case, the difference will be compensated if the error is recognized.
2.2 Determination of heat loss and circulation flow rates in the supply pipelines of the hot water supply system
Circulation flow rate of hot water in the system, l/s:
,(2.14)
where> is the total heat loss from the supply pipelines DHW systems, kW;
The temperature difference in the supply pipelines of the system to the most remote water collection point is assumed to be 10;
Circulation misregulation coefficient, accepted 1
For a system with variable resistance of circulation risers, the value is determined from the supply pipelines and water risers at = 10 and = 1
Heat loss in areas, kW, is determined by the formula
Where: q - heat loss of 1 m of pipeline, W/m, taken according to Appendix 7
l - length of the pipeline section, m, taken according to the drawing
When calculating the heat loss of sections of water risers, the heat loss of a heated towel rail is taken to be 100 W, while its length is excluded from the length of the riser. For convenience, the calculation of heat loss is summarized in one table 2 with hydraulic calculation networks.
Let us determine the heat loss for the entire system as a whole. For convenience, it is accepted that risers located on the plan in mirror image are equal to each other. Then the heat loss of the risers located to the left of the input will be equal to:
1.328*2+0.509+1.303*2+2.39*2+2.432*2+2.244=15.659 kW
And the risers located on the right:
1.328*2+(0.509-0.144) +2.39*2+(0.244-0.155) =7.89 kW
The total heat loss per house will be 23.55 kW.
Let's determine the circulation flow:
l/s
Let us determine the calculated second consumption of hot water, l/s, in sections 45 and 44. To do this, we determine the ratio qh/qcir; for sections 44 and 45 it is equal to 4.5 and 5.5, respectively. According to Appendix 5, the coefficient Kcir = 0 in both cases, therefore, the preliminary calculation is final.
Provided for circulation circulation pump brand WILO Star-RS 30/7
2.3 Selection of water meter
acc. from clause a) clause 3.4, we check the condition 1.36m
3. Calculation and design of the sewerage system
The sewerage system is designed to remove from the building contaminants generated during sanitary and hygienic procedures, economic activity, as well as atmospheric and melt waters. Internal sewer network consists of outlet pipelines, risers, outlets, exhaust part, and cleaning devices. Discharge pipes are used to drain Wastewater from sanitary fixtures and transferring them to the riser. The outlet pipes are connected to the water seals of sanitary fixtures and laid with a slope towards the riser. Risers are designed to transport wastewater to the sewer outlet. They collect wastewater from drainage pipes and must have a diameter of at least largest diameter outlet pipe or outlet of a device connected to the riser.
In this project, the intra-apartment wiring is made of bell-shaped PVC pipes with a diameter of 50 mm, risers with a diameter of 100 mm are made of cast iron, also connected by sockets. Connection to risers is made using crosses and tees. The network is subject to inspections and cleaning to remove blockages.
3.1 Determination of estimated sewerage costs
Total maximum design water flow:
Where: - water consumption by the device is assumed to be 0.3 l/s, respectively. from app. 4; - coefficient depending on the total number of devices and the probability of their use Рtot
, (7)
Where: - general norm consumption per hour of greatest water consumption, l, taken in accordance with Appendix 4 to be equal to 20
Number of water consumers equal to 104 * 4.2 people
Number of sanitary fixtures, accepted 416 as ordered
Then, the product N*=416*0.019=7.9, therefore =3.493
The resulting value is less than 8 l/s, therefore, the maximum second wastewater flow:
Where: - consumption from sanitary - technical device with the highest water drainage, l/s, adopted according to Appendix 2 for a toilet with a flush tank equal to 1.6
3.2 Calculation of risers
The water consumption for risers K1-1, K1-2, K1-5, K1-6 will be the same, since an equal number of devices are connected to these risers, each with 52 devices.
We assume the diameter of the riser is 100 mm, the diameter of the floor outlet is 100 mm, the angle of the floor outlet is 90°. Maximum throughput 3.2 l/s. Estimated flow rate 2.95 l/s. Consequently, the riser operates in normal hydraulic mode.
The water consumption for risers K1-3, K1-4 will be the same, since an equal number of devices are connected to these risers, each with 104 devices.
Heat losses DQ, (W), in the calculated section of the supply pipeline or riser are determined by standard specific heat losses or by calculation using the formula:
Where TO - heat transfer coefficient of an insulated pipeline, K=11.6 W/(m 2 -°C); t g av - average water temperature in the system, t g avg,=(t n +t k)/2,°C; t n, - temperature at the outlet of the heater (temperature of hot water at the entrance to the building), °C; t to - temperature at the most distant water tap, °C; h- Thermal insulation efficiency (0.6); / - length of the pipeline section, m; d H - outer diameter of the pipeline, m; t 0 - ambient temperature, °C.
Water temperature at the most distant water tap t to should be taken 5 °C below the water temperature at the entrance to the building or at the outlet of the heater.
Ambient temperature t 0 when laying pipelines in furrows, vertical channels, communication shafts and shafts of sanitary cabins, it should be taken equal to 23 ° C, in bathrooms - 25 ° C, in kitchens and toilet rooms of residential buildings, dormitories and hotels - 21 ° C.
Bathrooms are heated by heated towel rails, so heat losses from heated towel rails are added to the heat loss of the riser in the amount 100p(W), where 100 W is the average heat transfer from one heated towel rail, P - number of heated towel rails connected to the riser.
When determining circulation water flow rates, heat losses through circulation pipelines are not taken into account. However, when calculating hot water supply systems with heated towel rails on circulation risers, it is advisable to add the heat transfer of heated towel rails to the amount of heat loss by the supply heat pipes. This increases the circulation flow of water, improves the heating of heated towel rails and heating of bathrooms. The calculation results are entered into the table.
| № | l, m | D, m | t 0 , o C | t g av -t 0, o C | 1-n | q, W/m | DQ, W | åDQ, W | Note |
| Boner 6 | |||||||||
| 1-3 | 0,840 | 0,0213 | 21,00 | 36,50 | 0,30 | 8,4996 | 7,139715 | 7,139715 | |
| 2-3 | 1,045 | 0,0268 | 21,00 | 36,50 | 0,30 | 10,6944 | 11,17566 | 18,31537 | |
| 3-4 | 2,9 | 0,0268 | 21,00 | 36,50 | 0,30 | 10,6944 | 31,01379 | 49,32916 | |
| 4-5 | 2,9 | 0,0335 | 21,00 | 36,50 | 0,30 | 13,3680 | 38,76723 | 88,09639 | åDQ=497.899+900= |
| 5-6 | 2,9 | 0,0423 | 21,00 | 36,50 | 0,30 | 16,8796 | 48,95086 | 137,0473 | =1397.899 W |
| 6-7 | 2,9 | 0,0423 | 21,00 | 36,50 | 0,30 | 16,8796 | 48,95086 | 185,9981 | |
| 7-8 | 2,9 | 0,0423 | 21,00 | 36,50 | 0,30 | 16,8796 | 48,95086 | 234,9490 | |
| 8-9 | 2,9 | 0,0423 | 21,00 | 36,50 | 0,30 | 16,8796 | 48,95086 | 283,8998 | |
| 9-10 | 2,9 | 0,0423 | 21,00 | 36,50 | 0,30 | 16,8796 | 48,95086 | 332,8507 | |
| 10-11 | 2,9 | 0,0423 | 21,00 | 36,50 | 0,30 | 16,8796 | 48,95086 | 381,8016 | |
| 11-12 | 4,214 | 0,048 | 5,00 | 52,50 | 0,30 | 27,5505 | 116,0979 | 497,8994 | |
| 12-13 | 4,534 | 0,048 | 5,00 | 52,50 | 0,30 | 27,5505 | 124,9140 | 622,8134 | |
| 13-14 | 13,156 | 0,048 | 5,00 | 52,50 | 0,30 | 27,5505 | 362,4545 | 985,2680 | |
| 14-15 | 4,534 | 0,060 | 5,00 | 52,50 | 0,30 | 34,4381 | 156,1425 | 1141,4105 | |
| 15-Input | 6,512 | 0,060 | 5,00 | 52,50 | 0,30 | 34,4381 | 224,2612 | 1365,6716 | |
| Riser 1 | |||||||||
| 1a-3a | 0,840 | 0,0213 | 21,00 | 36,50 | 0,30 | 8,4996 | 7,139715 | 7,139715 | åDQ=407.504+900= =1307.504 W |
| 2a-3a | 1,045 | 0,0268 | 21,00 | 36,50 | 0,30 | 10,6944 | 11,17566 | 18,31537 | |
| 3a-4a | 2,9 | 0,0268 | 21,00 | 36,50 | 0,30 | 10,6944 | 31,01379 | 49,32916 | |
| 4a-5a | 2,9 | 0,0268 | 21,00 | 36,50 | 0,30 | 10,6944 | 31,01379 | 80,34294 | |
| 5a-6a | 2,9 | 0,0268 | 21,00 | 36,50 | 0,30 | 10,6944 | 31,01379 | 111,3567 | |
| 6a-7a | 2,9 | 0,0335 | 21,00 | 36,50 | 0,30 | 13,3680 | 38,76723 | 150,1240 | |
| 7a-8a | 2,9 | 0,0335 | 21,00 | 36,50 | 0,30 | 13,3680 | 38,76723 | 188,8912 | |
| 8a-9a | 2,9 | 0,0335 | 21,00 | 36,50 | 0,30 | 13,3680 | 38,76723 | 227,6584 | |
| 9a-10a | 2,9 | 0,0335 | 21,00 | 36,50 | 0,30 | 13,3680 | 38,76723 | 266,4257 | |
| 10a-11a | 2,9 | 0,0335 | 21,00 | 36,50 | 0,30 | 13,3680 | 38,76723 | 305,1929 | |
| 11a-15 | 4,214 | 0,0423 | 5,00 | 52,50 | 0,30 | 24,2789 | 102,3112 | 407,5041 | |
| 15-Input | 6,512 | 0,060 | 5,00 | 52,50 | 0,30 | 34,4381 | 224,2612 | 631,7652 |
åQп=5591.598 W
Hydraulic calculation of circulation pipelines
The circulating water flow rate in the hot water supply system G c (kg/h) is distributed proportionally to the total heat losses:
where åQ c is the total heat loss by all supply pipelines, W; Dt is the difference in water temperature in the supply pipelines of the hot water supply system, Dt=t g -t to =5°C; c is the heat capacity of water, J/(kg°C).
The circulation flow rates of water in the main sections of the hot water supply system consist of the circulation flow rates of sections and risers that are located in front along the direction of water movement.
Riser 1:
Section 2
Riser 2:
Section 3:
Riser 3:
Section 4:
Hydraulic calculation of circulation pipelines open system hot water supply.
| № | l, m | G, l/s | D, mm | w, m/s | R, Pa/m | K m | DP, Pa | åDP, Pa | |
| Circulation ring through riser 1 | |||||||||
| 15-16 | 6,512 | 0,267093 | 0,040 | 0,21367 | 44,719 | 0,2 | 1954,602 | 1954,602 | |
| 11-15 | 4,214 | 0,073767 | 0,020 | 0,2313 | 123,301 | 0,2 | 2293,472 | 4248,074 | |
| 1-11 | 0,073767 | 0,015 | 0,4326 | 579,868 | 0,5 | 399529,12 | 403777,20 | ||
| 1’-11’ | 0,073767 | 0,015 | 0,4326 | 579,868 | 0,5 | 399529,12 | 803306,32 | ||
| 11’-15’ | 4,214 | 0,073767 | 0,020 | 0,2313 | 123,301 | 0,2 | 2293,472 | 805599,79 | |
| 15’-16’ | 6,512 | 0,267093 | 0,040 | 0,21367 | 44,719 | 0,2 | 1954,602 | 807554,39 | |
| Circulation ring through riser 2 | |||||||||
| 15-16 | 6,512 | 0,267093 | 0,040 | 0,21367 | 44,719 | 0,2 | 1954,602 | 1954,602 | |
| 14-15 | 4,534 | 0,181492 | 0,032 | 0,1915 | 44,4186 | 0,2 | 953,399 | 2908,001 | |
| 11-14 | 4,214 | 0,073767 | 0,020 | 0,2313 | 123,301 | 0,2 | 2293,472 | 5201,473 | |
| 1-11 | 0,073767 | 0,015 | 0,4326 | 579,868 | 0,5 | 399529,12 | 404730,59 | ||
| 1’-11’ | 0,073767 | 0,015 | 0,4326 | 579,868 | 0,5 | 399529,12 | 804259,72 | ||
| 11’-14’ | 4,214 | 0,073767 | 0,020 | 0,2313 | 123,301 | 0,2 | 2293,472 | 806553,19 | |
| 14’-15’ | 4,534 | 0,181492 | 0,032 | 0,1915 | 44,4186 | 0,2 | 953,399 | 807506,59 | |
| 15’-16’ | 6,512 | 0,267093 | 0,040 | 0,21367 | 44,719 | 0,2 | 1954,602 | 809461,19 | |
| Circulation ring through riser 3 | |||||||||
| 15-16 | 6,512 | 0,267093 | 0,040 | 0,21367 | 44,719 | 0,2 | 1954,602 | 1954,602 | |
| 14-15 | 4,534 | 0,181492 | 0,032 | 0,1915 | 44,4186 | 0,2 | 953,399 | 2908,001 | |
| 13-14 | 13,156 | 0,099485 | 0,020 | 0,3085 | 209,147 | 0,2 | 36749,54 | 39657,542 | |
| 11-13 | 4,214 | 0,073767 | 0,020 | 0,2313 | 123,301 | 0,2 | 2293,472 | 41951,014 | |
| 1-11 | 0,073767 | 0,015 | 0,4326 | 579,868 | 0,5 | 399529,12 | 441480,07 | ||
| 1’-11’ | 0,073767 | 0,015 | 0,4326 | 579,868 | 0,5 | 399529,12 | 841009,12 | ||
| 11’-13’ | 4,214 | 0,073767 | 0,020 | 0,2313 | 123,301 | 0,2 | 2293,472 | 843320,59 | |
| 13’-14’ | 13,156 | 0,099485 | 0,020 | 0,3085 | 209,147 | 0,2 | 36749,54 | 880052,13 | |
| 14’-15’ | 4,534 | 0,181492 | 0,032 | 0,1915 | 44,4186 | 0,2 | 953,399 | 881005,53 | |
| 15’-16’ | 6,512 | 0,267093 | 0,040 | 0,21367 | 44,719 | 0,2 | 1954,602 | 882960,13 | |
| Circulation ring through riser 4 | |||||||||
| 15-16 | 6,512 | 0,267093 | 0,040 | 0,21367 | 44,719 | 0,2 | 1954,602 | 1954,602 | |
| 14-15 | 4,534 | 0,181492 | 0,032 | 0,1915 | 44,4186 | 0,2 | 953,399 | 2908,001 | |
| 13-14 | 13,156 | 0,099485 | 0,020 | 0,3085 | 209,147 | 0,2 | 36749,54 | 39657,542 | |
| 12-13 | 4,534 | 0,006592 | 0,020 | 0,0201 | 11,2013 | 0.2 | 240,4178 | 39897,960 | |
| 11-12 | 4,214 | 0,073767 | 0,020 | 0,2313 | 123,301 | 0,2 | 2293,472 | 42191,432 | |
| 1-11 | 0,073767 | 0,015 | 0,4326 | 579,868 | 0,5 | 399529,12 | 441720,48 | ||
| 1’-11’ | 0,073767 | 0,015 | 0,4326 | 579,868 | 0,5 | 399529,12 | 841249,54 | ||
| 11’-12’ | 4,214 | 0,073767 | 0,020 | 0,2313 | 123,301 | 0,2 | 2293,472 | 843543,01 | |
| 12’-13’ | 4,534 | 0,006592 | 0,020 | 0,0201 | 11,2013 | 0.2 | 240,4178 | 843783,43 | |
| 13’-14’ | 13,156 | 0,099485 | 0,020 | 0,3085 | 209,147 | 0,2 | 36749,54 | 880532,87 | |
| 14’-15’ | 4,534 | 0,181492 | 0,032 | 0,1915 | 44,4186 | 0,2 | 953,399 | 881486,37 | |
| 15’-16’ | 6,512 | 0,267093 | 0,040 | 0,21367 | 44,719 | 0,2 | 1954,602 | 883440,97 | |
We determine the discrepancy of pressure losses in two directions through the near and far risers using the formula: DH ch - pressure loss in the water meter, m; H St - available free pressure at the bath mixer (3m); DH cm - losses in the mixer (5 m); N g - geometric height of water rise from the axis of the pipeline at the inlet to the axis of the highest located water tap (24.2 m).
The water meter is selected based on water flow at the inlet G and nominal diameter Dy By . Pressure loss in the water meter DH mid(m), are determined by the formula:
where S is the hydraulic resistance of the water meter, taken according to (0.32 m/(l/s 2)). We accept the VK-20 water meter.
Excessive inlet pressure:
Bibliography.
1. Building codes and regulations. SNiP 3.05.01-85. Internal sanitary systems. M: Stroyizdat, 1986.
2. Building codes and regulations. SNiP 2.04.01-85. Internal water supply and sewerage of buildings. M.: Stroyizdat, 1986.
3. Building codes and regulations. SNiP II-34-76. Hot water supply. M.: Stroyizdat, 1976.
4. Designer's Handbook. Heating, water supply, sewerage / Ed. I. G. Staroverova. - M.: Stroyizdat, 1976. Part 1.
5. Handbook of heat supply and ventilation / R.V. Shchekin, S.M. Korenevsky, G.E. Bem, etc. - Kyiv: Budivelnik, 1976. Part 1.
6. Heat supply: Textbook for universities / A. A. Ionin, B. M. Khlybov, etc.; Ed. A. A. Ionina. M.: Stroyizdat, 1982.
7. Heat supply (course design): Textbook for universities on special topics. “Heat and gas supply and ventilation” / V. M. Kopko, N. K. Zaitseva and others; Ed. V. M. Kopko. - Mn.: Higher. school, 1985.
8. Heat supply: Tutorial for university students / V. E. Kozin, T. A. Levina, A. P. Markov, etc. - M.: Vyssh. school, 1980.
9. Zinger N. M. Hydraulic and thermal conditions heating systems. - M.: Energoatomizdat, 1986.
10. Sokolov E.Ya. District heating and heating networks. - M.: MPEI Publishing House, 2001.
11. Setup and operation of water heating networks: Directory / V. I. Manyuk, Ya. I. Kaplinsky, E. B. Khizh and others - M.: Stroyizdat, 1988.
A new column has appeared in receipts for utility services - hot water supply. It caused confusion among users, since not everyone understands what it is and why it is necessary to make payments on this line. There are also apartment owners who cross out the box. This entails the accumulation of debt, penalties, fines and even litigation. In order not to take matters to extreme measures, you need to know what DHW is, DHW heat energy and why you need to pay for these indicators.
What is DHW on the receipt?
DHW - this designation stands for hot water supply. Its goal is to provide apartments in apartment buildings and other residential premises with hot water at an acceptable temperature, but hot water supply is not the hot water itself, but the thermal energy that is spent on heating the water to an acceptable temperature.
Experts divide hot water supply systems into two types:
- Central system. Here the water is heated at a heating station. After this, it is distributed to apartments in multi-apartment buildings.
- Autonomous system. It is usually used in private homes. The principle of operation is the same as in the central system, but here the water is heated in a boiler or boiler and is used only for the needs of one specific room.
Both systems have the same goal - to provide home owners with hot water. In apartment buildings, a central system is usually used, but many users install a boiler in case the hot water is turned off, as has happened more than once in practice. An autonomous system is installed where it is not possible to connect to the central water supply. Only those consumers who use the central heating system pay for hot water supply. Users of an autonomous circuit pay for utility resources that are spent to heat the coolant - gas or electricity.
Important! Another column in the receipt related to DHW is DHW at one unit. Decoding ODN - general house needs. This means that the DHW column on one unit is the expenditure of energy on heating water used for the general needs of all residents of an apartment building.
These include:
- technical work that is performed before the heating season;
- pressure testing of the heating system carried out after repair;
- repair work;
- heating of common areas.
Hot water law
The law on hot water supply was adopted in 2013. Government Decree No. 406 states that users of a central heating system are required to pay a two-part tariff. This suggests that the tariff was divided into two elements:
- thermal energy;
- cold water.
This is how DHW appeared on the receipt, that is, the thermal energy spent on heating cold water. Housing and communal services specialists came to the conclusion that risers and heated towel rails, which are connected to the hot water supply circuit, consume thermal energy to heat non-residential premises. Until 2013, this energy was not taken into account in receipts, and consumers used it free of charge for decades, since the air in the bathroom continued to be heated outside the heating season. Based on this, officials divided the tariff into two components, and now citizens have to pay for hot water.
Water heating equipment
The equipment that heats the liquid is a water heater. Its breakdown does not affect the hot water tariff, but users are required to pay the cost of repairing the equipment, since water heaters are part of the property of homeowners in an apartment building. The corresponding amount will appear in the receipt for the maintenance and repair of the property.
Important! This payment should be carefully considered by the owners of those apartments that do not use hot water, since their housing has an autonomous heating system installed. Housing and communal services specialists do not always pay attention to this, simply distributing the amount for water heater repairs among all citizens.
As a result, these apartment owners have to pay for equipment they did not use. If you discover an increase in the tariff for repairs and maintenance of property, you need to find out what this is connected with and contact the management company for recalculation if the payment was calculated incorrectly.
Thermal energy component
What is this - a coolant component? This is heating cold water. The thermal energy component does not have a meter installed, unlike hot water. For this reason, it is impossible to calculate this indicator using a counter. How, in this case, is the thermal energy for hot water calculated? When calculating the payment, the following points are taken into account:
- tariff set for hot water supply;
- expenses spent on maintaining the system;
- cost of heat loss in the circuit;
- costs spent on coolant transfer.
Important! The cost of hot water is calculated taking into account the volume of water consumed, which is measured in 1 cubic meter.
The size of the energy fee is usually calculated based on the readings of the common hot water meter and the amount of energy in the hot water. Energy is also calculated for each individual apartment. To do this, water consumption data is taken, which is learned from the meter readings, and multiplied by the specific heat energy consumption. The received data is multiplied by the tariff. This figure is the required contribution, which is indicated on the receipt.
How to make your own calculation
Not all users trust the payment center, which is why the question arises of how to calculate the cost of hot water supply yourself. The resulting figure is compared with the amount on the receipt and on the basis of this a conclusion is made about the correctness of the charges.
To calculate the cost of hot water supply, you need to know the tariff for thermal energy. The amount is also affected by the presence or absence of a meter. If there is one, then readings are taken from the meter. In the absence of a meter, the standard for the consumption of thermal energy used to heat water is taken. This standard indicator is established by an energy saving organization.
If an energy consumption meter is installed in a multi-storey building and the housing has a hot water meter, then the amount for hot water supply is calculated based on general building metering data and the subsequent proportional distribution of the coolant among apartments. If there is no meter, the rate of energy consumption per 1 cubic meter of water and the readings of individual meters are taken.
Complaint due to incorrect calculation of receipt
If, after independently calculating the amount of contributions for hot water supply, a difference is identified, you must contact the management company for clarification. If the organization's employees refuse to provide explanations on this matter, a written complaint must be submitted. Company employees have no right to ignore it. The response must be received within 13 working days.
Important! If no response is received or it is not clear from it why this situation arose, then the citizen has the right to file a claim with the prosecutor’s office or a statement of claim in court. The authority will consider the case and make an appropriate objective decision. You can also contact organizations that control the activities of the management company. Here the subscriber's complaint will be considered and an appropriate decision will be made.
Electricity used to heat water is not a free service. Payment for it is charged on the basis of the Housing Code of the Russian Federation. Each citizen can independently calculate the amount of this payment and compare the data obtained with the amount on the receipt. If any inaccuracy occurs, you should contact the management company. In this case, the difference will be compensated if the error is recognized.
