Calculation of water supply with an example. Calculation of key indicators characterizing the technical level of water supply systems How to calculate the reserve power of cold water supply

An important part of monitoring is determining the utilization rate of the production capacity of water supply networks and structures. The coefficient of utilization of the production capacity of water intake structures (water treatment facilities, water supply networks) is determined by the ratio of the amount of actual water supply per day to the installed design capacity of water supply per day. The water supply capacity reserve can be used when commissioning additional housing stock or other consumer facilities. However, it is necessary to compare the availability of additional capacity with existing reserves, for example, with the additional capacity of treatment facilities, with the throughput of filters, and the presence of intermediate reservoirs. The study of the use of power of water supply systems should be supplemented by an analysis of data on the length of water supply and street networks, water losses during accidents, and data on the number of accidents.

The second information block provides information for a real assessment of the condition of water supply systems and includes the following group of indicators - see. table 30.

Table 30. Indicators of the technical level of water supply systems

	Indicator name	base period	reporting period	forecast period
1.	Production capacity utilization rate of water intake structures, %	40,19	41,79	43,88
2.	Production capacity utilization rate of water treatment facilities, %	46,92	50,15	50,65
3.	Water pipeline production capacity utilization rate, %	45,90	45,56	45,76
4.	Specific consumption energy for raising water, kW. hour/m3	0,70	0,68	0,59
5.	Specific energy consumption for water treatment, kW. hour/m3	0,050	0,050	0,043
6.	Specific energy consumption for water transportation, kW. hour/m3	0,650	0,640	0,555
7.	Accident coefficient, characterizing the number of accidents in water supply networks per 1 km of network; number of accidents/100 km/year	11,02	11,47	9,04
8.	Proportion of accidents on water supply networks exceeding the liquidation period to the total number of accidents, %		4,65	2,86
9.	Ratio of the number of constructed and reconstructed water supply networks to the total length of the enterprise networks, %	1,38	2,67	2,98

1. Factor of utilization of production capacity of water intake structures (KIPM water construction), %.

2. Factor of utilization of production capacity of water treatment facilities (CIPM soor. water.), %

3. Coefficient of utilization of water supply production capacity (KIPM water supply), %

4. Specific energy consumption for lifting (water treatment, water transportation), kW. hour/m3

5. Accident coefficient, characterizing the number of accidents in water supply networks per 1 km of network (CA water); number of accidents/km/year

6. The share of accidents on water supply networks with exceeding the liquidation period to the total number of accidents, % (YES water)

7. Ratio of the number of constructed and reconstructed water supply networks to the total length of the enterprise networks, (KR water)%

(9.1),

where M is fact. V. coor. - actual capacity of water intake structures, thousand m3/day; M project. V. coor. - design capacity of water intake structures, thousand m3/day.

(9.2),

where M is fact. coor. water - actual capacity of water treatment facilities, thousand m3/day; M project. coor. water . - design capacity of water treatment facilities, thousand m3/day.

(9.3),

where M is fact. water supply - actual water supply capacity, thousand m3/day; M project. water supply . - design capacity of water supply structures, thousand m3/day.

The indicator (OP) is calculated using the formula.

Representatives of many large enterprises and organizations are currently interested in the issue of introducing mandatory payment for power reserves. IN Lately At the level of the Russian Government, the issue of mandatory payment for the “surplus” of the available maximum power allocated to consumers is being actively discussed - that is, the introduction of the so-called capacity reserve fee. Currently, there are already developed draft resolutions of the Government of the Russian Federation, which oblige all consumers-legal entities (except for the population and equivalent categories - they do not pay for the power reserve) to pay for the maximum power reserve if several conditions are met. It is worth noting separately that for now this is just a project and consumers do not need to worry about additional costs for energy supply. But we have to admit that with a high degree of probability, the published projects will actually be signed and a fee will be charged for the maximum power reserve.

Therefore, consumers need a clear understanding of how payment for the maximum power reserve will be made and what actions need to be taken to minimize the cost of paying for the reserve.

In accordance with the existing draft resolution, the power reserve is defined as the difference between the maximum power and the network power. At the same time, the amount of network power for consumers with a maximum power of at least 670 kW is determined in the general procedure provided for determining the amount of network power (as when calculating consumers in the 4th price category), and for consumers less than 670 kW is determined as the product of a coefficient of 0.002667 and actual consumption of electrical energy for the billing period.

Then, after determining the power reserve, the electricity supplier (electricity grid company) compares the obtained result of calculating the power reserve with the maximum power value. If the power reserve is a value exceeding 40% of the maximum power agreed upon with the electric grid company, and also for a long period of time previously this condition was met for such a consumer (at least 12 months in a row), then the electric grid company (electricity supplier) has the right to present to the consumer calculated cost of power reserve.

The cost of the power reserve is calculated as the product of the reserve itself, the rate for the maintenance of networks of the two-rate version of the tariff for electricity transmission and the reducing coefficient of payment for the reserve. This coefficient in the first year of application of this procedure is 0.05, in the second 0.1, in the third year - 0.15 and in the fourth and subsequent years - 0.2.

It is worth noting that the electric grid company, before invoicing consumers with power reserves, is obliged to inform consumers about the opportunity to refuse part of the maximum power in favor of the electric grid company.

A water supply system is a set of pipelines and devices that ensure an uninterrupted supply of water to various sanitary fixtures and other devices that require it to operate. In its turn water supply calculation- this is a set of measures, as a result of which the maximum second, hourly and daily water consumption is initially determined. Moreover, not only the total liquid consumption is calculated, but also the consumption of cold and hot water separately. The remaining parameters described in SNiP 2.04.01-85 * "Internal water supply and sewerage of buildings", as well as the diameter of the pipeline, are already dependent on water consumption indicators. For example, one of these parameters is the nominal diameter of the meter.

This article presents example of calculating water supply for internal water supply for a private 2-storey house. As a result of this calculation, the total second water flow and the diameters of pipelines for plumbing fixtures located in the bathroom, toilet and kitchen were found. It also defines the minimum cross-section for the entrance pipe to the house. That is, we mean a pipe that originates at the source of water supply and ends at the point where it branches to consumers.

Regarding the other parameters given in the mentioned regulatory document, then practice shows that it is not necessary to calculate them for a private house.

Example of water supply calculation

Initial data

The number of people living in the house is 4 people.

The house has the following sanitary fixtures.

Bathroom:

Bathroom with faucet - 1 pc.

San. node:

Toilet with flush tank - 1 pc.

Kitchen:

Washbasin with mixer - 1 pc.

Calculation

Formula for maximum second water flow:

q с = 5 q 0 tot α, l/s,

Where: q 0 tot - total liquid consumption of one consumed device, determined in accordance with clause 3.2. We accept by adj. 2 for the bathroom - 0.25 l/s, wc. node - 0.1 l/s, kitchen - 0.12 l/s.

α - coefficient determined according to app. 4 depending on the probability P and the number of plumbing fixtures N.

Determining the probability of operation of sanitary fixtures:

P = (U q hr,u tot) / (q 0 tot ·N·3600) = (4·10.5) / (0.25·3·3600) = 0.0155,

Where: U = 4 people - number of water consumers.

q hr,u tot = 10.5 l - the total rate of water consumption in liters by the consumer at the hour of greatest water consumption. We accept according to the adj. 3 for an apartment-type residential building with water supply, sewerage and bathtubs with gas water heaters.

N = 3 pcs. - number of plumbing fixtures.

Determining water flow for a bathroom:

α = 0.2035 - we accept according to the table. 2 adj. 4 depending on NP = 1·0.0155 = 0.0155.

q s = 5·0.25·0.2035 = 0.254 l/s.

Determination of water consumption for toilets. node:

α = 0.2035 - exactly the same as in the previous case, since the number of devices is the same.

q s = 5·0.1·0.2035 = 0.102 l/s.

Determining water consumption for the kitchen:

α = 0.2035 - as in the previous case.

q s = 5·0.12·0.2035 = 0.122 l/s.

Determination of the total water consumption for a private house:

α = 0.267 - since NP = 3·0.0155 = 0.0465.

q s = 5·0.25·0.267 = 0.334 l/s.

Formula for determining the diameter of the water supply pipe in the design area:

d = √((4 q с)/(π·V)) m,

Where: d is the internal diameter of the pipeline in the calculated section, m.

V - water flow speed, m/s. We take it equal to 2.5 m/s according to clause 7.6, which states that the speed of the liquid in the internal water supply cannot exceed 3 m/s.

q c is the fluid flow rate in the area, m 3 /s.

Determining the internal cross-section of a bathroom pipe:

d = √((4 0, 000254)/(3.14·2.5)) = 0.0114 m = 11.4 mm.

Determination of the internal section of the pipe for the bathroom. node:

d = √((4 0, 000102)/(3.14·2.5)) = 0.0072 m = 7.2 mm.

Determining the internal cross-section of a kitchen pipe:

d = √((4 0, 000122)/(3.14·2.5)) = 0.0079 m = 7.9 mm.

Determining the internal cross-section of the entrance pipe to the house:

d = √((4 0, 000334)/(3.14·2.5)) = 0.0131 m = 13.1 mm.

Conclusion: To supply water to a bathtub with a mixer, a pipe with an internal diameter of at least 11.4 mm is required, the toilet bowl to the bathroom. node - 7.2 mm, washbasin in the kitchen - 7.9 mm. As for the inlet diameter of the water supply system into the house (to supply 3 appliances), it must be at least 13.1 mm.