There are several hydraulic calculation methods for indoor hot water heating systems

Hydraulic calculations for pressurized pipes:

1. The water pressure of the water source is determined, and the pipe diameter D is determined according to the reasonable flow rate V (or economic flow rate).

d= [4q ( v)] According to the calculated value, close to the selected standard pipe diameter) 2, the length of the pipe and the pressure difference between the two ends are known, and the pipe diameter is determined.

The flow rate q is not only related to the inner diameter of the pipe d, but also related to the pressure drop (pressure slope) i per unit length of the pipe, i=(p1-p2) lThe specific relationship can be derived as follows:

The pressure slope of the pipe can be calculated using the Sheverev formula i=

The flow rate of the pipeline Q = ( d 2 4) v - 2) the flow velocity v is eliminated by the second formula: q = (i in kpa m) pipe diameter: d = (d in m).

This is the formula for finding the pipe diameter for the flow rate and pressure slope of the known pipe.

For example, if a pipeline is 100m long, the starting pressure of the pipeline is p1=96kpa, and the end pressure is p2=20kpa, the flow rate of the pipeline through l s is required, and the pipe diameter is determined by trying.

Pressure slope i=(p1-p2) l=(96-20) 100=flow rate q= l s= m 3 s

Pipe diameter d= = =400mm

Hassen's William formula can also be used: i=105c (i is in kpa m).

Steel pipe, cast iron pipe: c=100, i= q = i copper pipe, stainless steel pipe: c=130, i= q = i plastic pipe:

c=140，i= ^ q = i ^c=150，i= ^ q = i ^

First of all, you need to determine the amount of heat you need, your base water temperature, the water temperature you need, and get the amount of heat you need.

Then you need to take this hourly heat away through the circulation of the water pump and transfer it to the unit that needs it.

Then you can get the flow rate of the pump, and another parameter of the pump is the head, how to calculate the head, it depends on the height of your system.

g=[q/c(tg-th)]×3600=

where g - calculated water flow, kg h, q - heat user design heat load, w, c - specific heat of water, c = 4187j kgo

The design supply and return temperature is generally estimated at 2 kg h per square meter of floor area. For the steam heat exchanger unit, because the temperature difference between the supply and return water is designed to be calculated according to 20, the water volume is often taken kg h.

g=[q/c(tg-th)]×3600=。

Typically, it is estimated at 2 kg h per square meter of floor area. For the steam heat exchanger unit, because the temperature difference between the supply and return water is designed to be calculated according to 20, the water volume is often taken kg h.

In the central heating system, the change of outdoor temperature is usually used as the basis for adjustment to adapt to the change of heat load of the heating system. According to the different adjustment locations, heat supply regulation is divided into centralized regulation, local regulation and individual regulation. Centralized adjustment is adjusted at the heat source, local adjustment is adjusted at the heat station or user system entrance, and individual adjustment is adjusted at the heat dissipation equipment, mainly relying on the action of the temperature control valve.

For hot water heating systems, the circulating water flow is calculated by the following formula:

g = [q c(tg-th)] 3600 = where: g - calculated water flow, kg h

Q-Thermal user design heat load, w

c - specific heat of water, c = 4187 j kgo

tgth design for return water temperature,

In general, it is estimated on a per square metre floor area2. For the steam heat exchanger unit, the water volume is often taken because the temperature difference between the supply and return water is calculated according to 20.

The steam consumption of the heating system can be calculated as follows:

g = where: g - steam design flow, kg h

Q - Heating system heat load, W

r- latent heat of vaporization of steam, kj kg

h-Enthalpy difference of condensate from saturation to discharge, kj kg

The water capacity of the hot water heating system is about 30 tons of 10,000 square meters!

Folded it yourself, according to your floor area!!

g=[q/c(tg-th)]×3600=

where g - calculate the water flow, kg h, q - heat user design heat load.

w, c - specific heat of water.

c=4187j/ kgo℃

The design supply and return temperature is generally estimated at 2 kg h per square meter of floor area. For the steam response rotten heat exchanger unit, because the temperature difference between the supply and return water is calculated according to 20, the water volume is often taken kg h.

Hello, dear, I am happy to answer for you: what is the difference between the hydraulic calculation of the outdoor hot water heating pipe network and the gravity circulation disturbance network Answer: Hello dear, There are the following three differences:

The gravity flow pipeline is open, and there is a gap between the fluid and the pipe, like a river; The pressure flow pipeline is sealed, and there is no gap between the fluid and the pipe; The lead lifting of the fluid in the gravity flow pipeline is carried out by gravity, while the fluid in the pressure pipeline is propelled by the pressure of the front-end pump body. The fluid in the gravity flow pipeline is generally laminar, while the fluid in the pressure pipeline is generally a spiral turbulent movement. Urban sewer is gravity flow pipeline, fire fighting, tap water and other pressure flow pipes.

Answers]: a, c, d

See the Code for Design of Water Supply and Drainage in Buildings. Item A refers to Article 1 of the Code to determine the circulating flow rate of the circulating return pipe diameter pipeline through water conservancy calculation, and there is no residual flow concept; Items b and c refer to the provisions of Article 1 of the specification to explain that in the case of regular hot water, the water consumption is more concentrated, so in the case of hot water, the hot water circulation is not considered; Item d is referred to Article 1 of the specification, which should be determined according to the second flow rate of the corresponding Kai Belt main pipe. Note that the "Design Flow" bureau age may be the maximum hour flow, or it may be the design second flow, etc.

1. First of all, the total heat load and the heat load of each room are known;

2. Determine the temperature of supply and return;

3. Draw a rough water system diagram;

4. Calculate the flow rate according to the heat load and the temperature difference between the supply and return water;

5. Carry out hydraulic balance calculation, calculate the diameter of each main pipe, riser and branch pipe and the total resistance of the system;

6. After that, the pump is selected according to the resistance of the most unfavorable loop.

The basic steps are like this.

Know the area and heat load of the house, and use the hot water pipe hydraulic calculation table to find the pipe diameter.

Dear, hello Know the area and heat load of the house, how to find the pipe diameter with the hydraulic calculation table of the hot water pipe: the ** on hand is 95 degrees of water supply and 70 degrees of backwater. The water supply and return temperature of the actual project generally does not reach 95 70, and the g in the table is the flow rate, and the state and you divide it by the heat load (water supply temperature - return water temperature) is this flow g.

PM is the specific friction resistance, the economic specific friction resistance in the textbook is 60 120, we often use 30 90, you find the g, and then control the specific friction resistance between 30 90, you can determine the pipe diameter and flow rate. Bucket reform.

For example: know the heating area of 1w square meters, know the heat load of 430kw, the temperature difference of 10 degrees, and find the pipe diameter:

kw= , converted into calories as: 368571 kcal, rounded to 370,000 kcal;

2. The circulating water volume is: 370,000 kcal 10 degrees = 37,000 kg hours (flow);

4. The economic flow rate of the heating pipeline is about: meters and seconds;

5. Calculation of pipeline diameter: a. flow rate = pipeline cross-sectional area x water velocity x 3600 seconds = area meter seconds x 3600 seconds x 1 ton cubic meter = 37 tons per hour;

b. Area = square meters; The diameter of the pipe is: m, 72 mm, round to DN80, optional: 89 pipes.

Send me the hydronic calculation sheet for the hot water pipe, and I'll do the math for you.