The effectiveness of our heating systems is essential to maintaining a warm and comfortable home. The rate at which the coolant moves through the system is one element in this equation that is frequently disregarded. Our energy bills and the comfort of our homes can both be significantly impacted by comprehending and optimizing this speed.
Imagine that your home’s circulatory system is similar to your heating system, with coolant serving as the blood that carries heat from the boiler to the radiators or subfloor pipes. Similar to how blood must flow at the proper rate to efficiently distribute nutrients, your heating system’s coolant must flow at the ideal speed to guarantee uniform heating throughout your living areas.
What does the term "speed of the coolant" actually mean, then? In a nutshell, it describes how fast the heated water or steam moves through the heating system’s pipes. Depending on the unit of measurement used in your area, this speed is usually expressed in meters per second or feet per minute.
Why does the coolant’s speed matter? To put it another way, consider this: if the coolant flows too slowly, it may take longer for the heat to distribute throughout your house, which could result in uncomfortable temperatures. Conversely, if coolant flows through the system too rapidly, it might not have enough time to effectively transfer heat to the surrounding air, wasting energy and raising heating costs.
Finding the ideal balance is the key to maximizing the coolant’s speed. The process entails modifying variables like pump settings, pipe diameter, and heating system layout to guarantee that the coolant flows at a rate that optimizes comfort and efficiency. A warmer, more energy-efficient home can be had by homeowners without going over budget if they take the time to fine-tune these parameters.
- Hydraulic heating calculation, taking into account the pipeline
- The flow rate of the coolant
- The speed of the coolant
- The choice of the main circuit
- Conclusion
- Hydraulic calculation of the heating system, taking into account pipelines.
- Hydraulic calculation of the heating system
- The flow rate of the coolant
- The speed of the coolant
- Pipe pressure losses
- Video on the topic
- Video 9 TM 4.1 Cumulator consumption in heating systems
- What is the maximum speed of the coolant in the heating system?
- At what speed should the circulation pump work.
Hydraulic heating calculation, taking into account the pipeline
Differential hydraulic heating systems
A few system operational parameters must be considered in order to perform an accurate hydraulic calculation of the heating system. This comprises the coolant’s velocity, flow rate, hydraulic resistance of the pipeline and shut-off valves, inertia, and other factors.
These parameters might not appear to be connected to one another. However, this is incorrect. Because of their direct relationship, they must be relied upon during analysis.
Let’s illustrate this relationship with an example. The resistance of the pipeline will rise instantly if the coolant’s speed is increased. Increased consumption causes the system’s hot water to flow more quickly, which raises resistance. The resistance of the pipeline decreases when the diameter of the pipes increases because the coolant moves more slowly.
What is the topic of discussion? All of this can be calculated so that the materials that are purchased will cost less. This represents the financial aspect of the issue.
There are four primary parts to the heating system:
- Boiler.
- Pipes.
- Heating devices.
- Locking and regulatory reinforcement.
Every one of these parts has unique resistance characteristics. Leading manufacturers must inevitably mention them because hydraulic properties are subject to change. They are mostly determined by the shape, style, and even material used to construct the heating system’s component parts. And when performing a hydraulic heating analysis, these particular qualities are the most crucial ones.
What qualities are hydraulic? These pressure losses are particular. That is to say, there is always resistance from the walls or the side of any type of heating element, be it a radiator, boiler, valve, or pipe. As a result, the coolant loses pressure and speed as it passes through them.
In the realm of house heating and insulation, the speed at which the coolant flows through the heating system plays a crucial role in its efficiency and effectiveness. This speed, often referred to as the flow rate, determines how quickly heat is distributed throughout the house. If the coolant flows too fast, it may not have enough time to absorb and carry sufficient heat, resulting in uneven heating and wasted energy. On the other hand, if the flow rate is too slow, heat distribution can be sluggish, leading to cold spots and discomfort. Achieving the optimal flow rate requires careful calibration of the heating system, considering factors like the size of the house, the type of heating system, and the insulation levels. By striking the right balance in coolant speed, homeowners can ensure consistent warmth, energy savings, and overall comfort in their living spaces.
The flow rate of the coolant
Using a basic heating circuit that consists of a heating boiler and heating radiators with kilowatt heat consumption as an example, we can demonstrate how a hydraulic heating calculation is made. And there are ten of these radiators in the system.
It’s crucial to correctly divide the plan into its component parts and to follow one rule: the pipe diameters shouldn’t change within any one section.
The pipeline that runs from the boiler to the first heating device makes up the first section. The pipeline connecting the first and second radiators is the second section. And so forth.
How does heat transfer happen and how does the coolant’s temperature drop? As the coolant enters the first radiator, it contributes a portion of the heat that is lowered by one kilowatt. The hydraulic calculation under 10 kilowatts is made in the first section. But there are already nine in the second section. And so on, decreasing.
Please be aware that this analysis is done independently for the supply circuit and the return.
You can figure out the coolant flow rate using the following formula:
C x (tr-too) / (3.6 x qCu) = G
Que is the site’s estimated thermal load. In our example, it is 10 kW at the first site and 9 kW at the second.
C: the water’s specific heat capacity, which is indicated by a constant value of 4.2 kJ/kg x s;
Tr is the coolant temperature at the site’s entrance;
To-the coolant’s temperature as you leave the location.
The speed of the coolant
The heating system has a minimum hot water speed at which the heating process operates at its best. The speed is 0.2-0.25 m/s. Should it drop, air will start to emerge from the water, causing air traffic congestion to form. Consequences: the boiler will boil and the heating will not function.
This is the bottom threshold; the upper limit should not be higher than 1.5 m/s. Overdoing puts the pipeline’s ability to produce noise at risk. 0.3–0.7 m/s is the most acceptable range for an indicator.
The characteristics of the material used to make the pipes must be considered if an accurate calculation of the water’s speed needs to be done. The roughness of the pipes’ interior surfaces is considered, particularly in this instance. Hot water, for instance, travels through steel pipes at a rate of 0.25–0.5 m/s, copper pipes at 0.25–0.7 m/s, and plastic pipes at 0.3–0.7 m/s.
The choice of the main circuit
Circuits for heating and boiler are divided by a hydraulic arrow.
Here, the one-pipe and two-pipe schemes need to be examined independently. In the first scenario, the calculation needs to be run via the riser with the highest load, which has a lot of installed shut-off valves and heating devices.
In the second scenario, the outline with the highest load is chosen. You must base your calculation on it. Hydraulic resistance will be substantially reduced in all other contours.
The lowest floor’s most heavily loaded ring is chosen if the horizontal pipe interchange is taken into account. The heat load indicates the workload.
Conclusion
The home’s heating
Let’s now review. As you can see, many factors need to be considered in order to perform a hydraulic analysis of the home’s heating system. The example was deliberately kept simple because, for example, it is very hard to understand a two-pipe heating system in a three-story house. You will need to get in touch with a specialized bureau to conduct this kind of analysis, where experts will examine the entire "On Bones" heating project.
It will be essential to consider more than just the aforementioned signs. Here, you will need to activate the system’s mode of operation, circulation pump power, temperature drop, loss of pressure, and so forth. Although there are numerous indicators, they are all included in GOST, so the expert can quickly sort things out.
The heating boiler’s power, the diameter of the pipes, the number and presence of shut-off valves, and the pump’s power are the only variables that need to be entered into the calculation.
Hydraulic calculation of the heating system, taking into account pipelines.
Heating system hydraulic calculation with pipelines taken into consideration.
All of the primary hydraulic parameters—such as the coolant’s flow rate, the hydraulic resistance of the pipelines and reinforcement, its speed, etc.—will be used in our additional computations. You must base your calculations on the full relationship that exists between these parameters.
For example, if you increase the speed of the coolant, at the same time the hydraulic resistance in the pipeline will increase. If we increase the flow rate of the coolant, taking into account the pipeline of a given diameter, the coolant speed will simultaneously increase, as well as hydraulic resistance. And the larger the diameter of the pipeline is, the less the coolant speed and hydraulic resistance will be. Based on the analysis of these relationships, you can turn the hydraulic calculation of the heating system (the calculation program is on the network) into an analysis of the efficiency and reliability of the entire system, which, in turn, will help reduce the costs of the materials used.
The heat generator, heating devices, pipeline, shut-off, and regulatory reinforcement are the four main parts of the heating system. Each of these components has unique hydraulic resistance characteristics that need to be considered when performing calculations. Keep in mind that hydraulic properties change over time. Prominent producers of materials and heating apparatus consistently provide details on particular pressure losses (hydraulic properties) related to their manufactured goods.
For instance, the nomogram above, which shows the precise loss of pressure or pressure in the pipeline for one meter of linear pipe, greatly simplifies the computation for Firat’s polypropylene pipelines. You can easily follow the relationships between the traits listed above by analyzing the nomogram. The fundamental idea behind hydraulic calculations is this.
Coolant consumption in hydraulic water heating system calculations
We believe that you have already made the comparison between "number of coolant" and "coolant consumption." Therefore, the type of thermal load that the coolant is subjected to when heat is transferred from the heat generator to the heating device will directly affect the coolant’s flow rate.
The hydraulic calculation includes figuring out the coolant’s level and flow rate in relation to the specified area. The plot in the calculation section has a constant diameter and a steady coolant flow rate.
Example of hydraulic calculation for heating systems
If the branch includes ten kilowatt radiators, and the heat carrier consumption was calculated on the transfer of heat energy at 10 kilowatts, then the calculated section will be a cut from the heat generator to the radiator, which is the first in the branch. But only on condition that this section is characterized by a constant diameter. The second section is located between the first radiator and the second radiator. At the same time, if in the first case the transfer of 10-kilowatt thermal energy was calculated, then in the second section the estimated amount of energy will be already 9 kilowatts, with a gradual decrease as calculations are carried out. Hydraulic resistance should be calculated simultaneously for the supply and reverse pipeline.
The coolant flow rate must be determined as part of the hydraulic calculation for a single-pipe heating system.
For the site that was determined using the formula below:
Que: The calculation site’s single load, expressed in watts. For instance, in our scenario, the first site’s heat load will be 10,000 watts, or 10 kilowatts.
C stands for specific heat capacity for water, which is a constant of 4.2 kJ/(kg • ° C).
TG is the heating system’s hot coolant temperature.
T is the heating system’s cold coolant temperature.
Calculating the heating system hydraulically: coolant flow rate
There should be a threshold value between 0.2 and 0.25 m/s for the minimum coolant rate. Less speed will cause the coolant’s excess air to be released. Air traffic jams will then start to appear in the system, which may result in the heating system refusing to operate entirely or partially. Regarding the upper threshold, the coolant speed ought to be between 0.6 and 1.5 m/s. It is unlikely that hydraulic noises will develop in the pipeline if the speed does not increase above this indicator. Based on practical experience, the ideal speed range for heating systems is between 0.3 and 0.7 m/s.
If there is a need to calculate the coolant speed range more accurately, then you will have to take into account the parameters of the material of the pipelines in the heating system. More precisely, you will need a roughness coefficient for an internal pipeline surface. For example, if we are talking about pipelines made of steel, then the speed of the coolant at 0.25 – 0.5 m/s is considered optimal. If the pipeline is polymer or copper, then the speed can be increased to 0.25 – 0.7 m/s. If you want to play it safe, carefully read what speed is recommended by manufacturers of equipment for heating systems. A more accurate range of the recommended speed of the coolant depends on the material of the pipelines used in the heating system, or rather on the coefficient of roughness of the inner surface of the pipelines. For example, for steel pipelines, it is better to adhere to the heat carrier speed from 0.25 to 0.5 m/s for copper and polymer (polypropylene, polyethylene, metal -plastic pipelines) from 0.25 to 0.7 m/С or use the manufacturer"s recommendations if they are available.
Pressure loss in the hydraulic resistance calculation of the heating system
Pressure loss on a particular system segment, also referred to as "hydraulic resistance," is the total of all losses in local resistances and hydraulic friction. This indicator’s PA value is determined using the following formula:
(ρ * ν2) / 2) * σζ = r * l + Δ ski
Where ν is the coolant speed in milliseconds (m/s).
The coolant’s density, expressed in kg/m3, is denoted by ρ.
The pressure in the pipeline, expressed in pa/m, is denoted by R.
The estimated length of the pipeline at the location, expressed in meters, is l.
Σζ is the total of the shut-off-regulating reinforcement’s coefficient and the local resistances in the equipment’s vicinity.
The total of all the hydraulic resistances of the sections that were calculated is the general hydraulic resistance.
Hydraulic calculation for a two-pipe heating system: selecting the primary branch
In the event that the coolant in the system exhibits a passing movement, the lower heating device of a two-pipe system will select the most loaded riser ring. A ring through the most heavily loaded riser for a single-pipe system.
In a two-pipe system, the lower heating ring is chosen for the farthest-reaching risers that are loaded if the coolant movement in the system is dead-end. As a result, in a single-pipe heating system, the most loaded rings from distant risers are used to choose a ring.
In the case of a horizontal heating system, the lowest floor’s most heavily loaded branch is used to choose a ring. When we talk about loading, we mean the previously mentioned "thermal load" indicator.
Hydraulic calculation of the heating system
Using hydraulic calculation, you can choose the right diameters and length of the pipes, correctly and quickly balance the system using radiator valves. The results of this calculation will also help to choose the right circulation pump. As a result of the hydraulic calculation, the following data must be obtained: M – the heat carrier consumption for the entire heating system, kg/s; Δp – pressure loss in the heating system; Δp1. Δp2. Δpn. -loss of pressure from the boiler (pump) to each radiator (from the first to the nd);
The flow rate of the coolant
The flow rate of the coolant is calculated by the formula: , where Q is the total power of the heating system, kW; The heat loss of the CP building is taken from the calculation of the specific heat capacity of the water, KJ/(kg*hail.C); For simplified calculations, we accept 4.19 kJ/(kg*degrees.C) Δpt – the temperature difference at the entrance and output; We usually take the boiler feed and return Coolant flow rate (only for water) q = kW; Δt = o C; m = l/s, you can also calculate the flow rate of the coolant on any section of the pipe. Sites are selected so that the pipe has the same water speed. Thus, division into areas occurs to the tee, or to reduction. It is necessary to smack by power all radiators to which the coolant flows through each section of the pipe. Then substitute the value in the formula above. These calculations must be done for pipes before each radiator.
The speed of the coolant
Then, using the obtained heat carrier consumption values, it is necessary to calculate for each section of the pipes in front of the radiators The speed of water in the pipes according to the formula : where V is the speed of the coolant, m/s; M – the flow rate of the coolant through the pipe section, kg/s ρ – water density, kg/cube.m. can be taken equal to 1000 kg/cube.m. f – the cross -sectional area of the pipe, sq.m. You can count by the formula: π * r 2. where R is the inner diameter divided by 2 Coaling calculator of the coolant m = l/s; mm pipe on mm; V = m/s
Pipe pressure losses
Next, you must compute for every site. Friction pressure loss in the pipe as determined by the following formula (feed and return are included): ΔPPtr – pressure loss due to friction in the pipe, pa; R – specific frictional losses in the pipe, pa/m; the length of the site, m, in the pipe manufacturer’s reference literature;
| Speed of Coolant | Impact on Heating System |
| Low | Slower heating, reduced efficiency |
| Medium | Balanced heating, moderate efficiency |
| High | Rapid heating, higher efficiency |
Maintaining ideal comfort and efficiency in your home’s heating system requires an understanding of the coolant’s speed. As we’ve seen, how quickly water moves through the system determines how quickly the temperature in your house rises or falls. You can fine-tune your heating system to better fit your needs and preferences by changing the coolant’s speed.
The most important lesson is that, in order to achieve more even heat distribution, a slower flow rate must be balanced with a faster flow rate for rapid heating. Finding the sweet spot that optimizes comfort and energy efficiency is crucial. Depending on your home’s size, the kind of heating system you have, and the climate where you live, this might need some trial and error.
Moreover, the lifespan and efficiency of your heating system can be affected by the coolant’s speed. Overflowing flow rates can overstress components, causing premature wear and possibly expensive repairs. However, a flow rate that is too slow could lead to inadequate heat delivery, which would be uncomfortable and unsatisfactory.
Ultimately, striking a harmonious balance between comfort, efficiency, and longevity is what it means to keep the coolant speed at the proper level. Maintaining optimal performance and extending the lifespan of your heating system requires routine maintenance, which includes checking and adjusting the flow rate as necessary. You can enjoy a warm and comfortable home while reducing energy waste and expenses by being proactive and knowledgeable.
