You “just” need to add a hydraulic arrow. After which you can connect in one system any number of boilers (also any) with any number of circuits with any consumers.
However, I made a reservation: in addition to the hydraulic switch, two more pumps were added - one for each boiler.
How does the scheme with a hydraulic arrow and two boilers work?
Boiler pumps supply coolant from the hydraulic pump to the boilers, where it heats up and again enters the hydraulic pump. The coolant is disassembled from the hydraulic arrow by circuit pumps - everyone takes as much as he needs, without obstacles. If the flow rates through the boilers and through the circuits differ, then part of the coolant will simply fall or rise inside the hydraulic arrow, adding where it is lacking. And the whole system will work stably.
Connecting two boilers: detailed diagram
And, as always, I provide a detailed diagram of such a connection:
Reminder. I talked about this several times, but I’ll repeat it: circulation pumps and check valves, which for each consumer circuit, can be installed not only, as in the diagram, after the supply manifold. But even before the return manifold - all three, or some this way, some this way, the main thing is to observe the direction of flow.
In the diagram above, the pump manifold is assembled from separately purchased parts. And the hydraulic arrow, accordingly, is also separate. But you can simplify and speed up the assembly of the heating system by using a unit that combines a manifold with a hydraulic valve.
In order to save money, it is often used to connect two boilers into one heating system. When purchasing several thermal devices, you should know in advance what methods exist for connecting them to each other.
Since a wood-burning boiler operates in an open system, it is not easy to combine it with a gas heating device, which has a closed system. With harness open type water heats up to a temperature of one hundred degrees or higher at the highest level high pressure. To protect the liquid from overheating, an expansion tank is installed.
Through open type tanks part of the hot water, which helps lower the pressure in the system. But the use of such drain tanks sometimes causes oxygen particles to enter the coolant.
There are two ways to connect two boilers into one system:
- parallel connection gas and solid fuel boiler together with safety devices;
- series connection of two boilers of different types using a heat accumulator.
With a parallel heating system in large buildings, each boiler heats its own half of the house. The sequential combination of a gas and wood-burning unit forms two separate circuits, which are combined with a heat accumulator.
Application of a heat accumulator
A heating system with two boilers has the following structure:
- the heat accumulator and gas boiler are combined with heating devices in a closed circuit;
- from the wood-burning heating device to the heat accumulator energy flows, which are transferred to a closed system.
Using a heat accumulator, you can operate the system simultaneously from two boilers or only from a gas and wood heating unit.
Parallel closed circuit
To combine wood and gas boiler systems, the following devices are used:
- safety valve;
- membrane tank;
- pressure gauge;
- air vent valve.
First of all, shut-off valves are mounted on the pipes of the two boilers. A safety valve, an air vent device, and a pressure gauge are installed near the wood-burning unit.
A switch is placed at the branch from the solid fuel boiler to operate the small circle circulation. Fix it at a distance of one meter from the wood-burning heating device. A check valve is added to the jumper, blocking the access of water to part of the circuit of the evacuated solid fuel unit.
The supply and return are connected to the radiators. The return flow of coolant is divided by two pipes. One is connected through a three-way valve to the jumper. Before branching these pipes, a tank and pump are installed.
In a parallel heating system, a heat accumulator can be used. The installation diagram of the device with this connection consists of connecting to it the return and supply lines, supply and return pipes to the heating system. For joint or separate operation of boilers, taps are installed on all system units to shut off the flow of coolant.
You can combine two heating devices using manual and automatic control.
Manual connection
Turning the boilers on and off is carried out manually due to two coolant taps. The piping is carried out using shut-off valves.
Expansion tanks are installed in both boilers and are used simultaneously. Experts recommend not completely cutting off the boilers from the system, but simply simultaneously connecting them to the expansion tank, blocking the flow of water.
Automatic connection
For automatic adjustment For two boilers, a check valve is installed. It protects outages heating unit from malicious streams. Otherwise, the method of circulating coolant in the system is no different from manual control.
IN automatic system all main lines must not be blocked. The working boiler pump drives the coolant through the non-working unit. Water moves in a small circle from the place where the boilers are connected to the heating system through the idle boiler.
In order not to waste most of the coolant for an unused boiler, check valves are installed. Their work should be directed towards each other, so that the water from the two heating equipment is directed to the heating system. Valves can be installed on return flow. Also when automatic control A thermostat is needed to regulate the pump.
Automatic and manual control used in combination different types heating devices:
- gas and solid fuel;
- electric and wood;
- gas and electric.
You can also connect two gas or electric boilers to one heating system. Installing more than two connected heating units results in reduced system efficiency. Therefore, more than three boilers are not connected.
Advantages of a two-boiler system
The main positive aspect of installing two boilers in one heating system is the continuous maintenance of heat in the room. A gas boiler is convenient because it does not need to be constantly maintained. But in case he emergency shutdown or in order to save money, a wood-burning boiler will become an indispensable heating addition.
The heating system of two boilers can significantly increase the level of comfort. To the advantages of double thermal device belong to:
- selection of the main fuel type;
- the ability to control the entire heating system;
- increasing the operating time of equipment.
Connecting two boilers to one heating system is best solution for heating buildings of any size. This solution will allow you to continuously maintain heat in the house for many years.
Most rational system heating is one in which the coolant becomes hot due to the operation of two or three boilers. However, they can be the same in power and type. This rationality is explained by the fact that one heat generator operates on full power only a few weeks a year. At other times, you need to reduce its productivity. And this leads to a drop in its efficiency and an increase in heating costs.
Several boilers combined into one heating system allow you to more flexibly control the operation of the piping without loss of efficiency, since it is enough to turn off one or two devices. In addition, if one of them breaks down, the system continues to raise the temperature in the house.
Types of connection of two or more boilers
Using a larger number of identical boilers requires a special connection diagram. You can combine them into one system:
- Parallel.
- Cascade or sequentially.
- According to the scheme of primary-secondary rings.
Features of parallel connection
There are following features:
- The hot coolant supply circuits of both boilers are connected to the same line. These circuits must have safety groups and valves. The latter can be closed manually or automatically. The second case is only possible when automation and servos are used.
- The return circuits of two heating boilers are connected to another line. These circuits also have valves that can be controlled by the above-mentioned automation.
- The circulation pump is located on the return line in front of the junction of the return pipes of the two boilers.
- Both lines are always connected to hydraulic collectors. There is an expansion tank on one of the collectors. In this case, a make-up pipe is connected to the end of the pipe to which the tank is connected. Of course, at the connection point there is a check valve and shut-off valve. The first does not allow hot coolant to enter the make-up pipe.
- Branches extend from the collectors to radiators, heated floors, and an indirect heating boiler. Each of them is equipped with its own circulation pump and coolant drain valve.
Using such a piping arrangement without automation is very problematic, since it is necessary to manually close the valves located on the supply and return pipes of one boiler. If this is not done, the coolant will move through the heat exchanger of the switched off boiler. And this turns out:
- additional hydraulic resistance in the water heating circuit of the device;
- an increase in the “appetite” of the circulation pumps (they must overcome this resistance). Accordingly, energy costs are rising;
- heat losses for heating the heat exchanger of a switched-off boiler.
Therefore, it is necessary to correctly install the automation, which will cut off the switched-off device from the heating system.
Cascade connection of boilers
The concept of cascading boilers provides for the distribution of the heat load between several units, which can operate independently and heat the coolant as much as the situation requires.
Can be cascaded like boilers with stepped gas burners, and with modulated ones. The latter, unlike the former, allow you to smoothly change the heating power. It is worth adding that if boilers have more than two stages of gas supply regulation, then the third and remaining stages make their productivity less. Therefore, it is better to use units with a modulating burner.
At cascade connection the main load falls on one of two or three boilers. The additional two or three devices turn on only when needed.
The features of this connection are as follows:
- The supply lines and controllers are designed in such a way that the coolant circulation can be controlled in each unit. This allows you to stop the flow of water in disconnected boilers and avoid heat loss through their heat exchangers or casings.
- Connecting the water supply lines of all boilers to one pipe, and the coolant return lines to the second. In fact, the connection of boilers to the mains occurs in parallel. Thanks to this approach, the coolant at the inlet of each unit has the same temperature. This also avoids the movement of heated fluid between disconnected circuits.
The advantage of parallel connection is the preheating of the heat exchanger before turning on the burner. True, this advantage occurs when burners are used that ignite the gas with a delay after turning on the pump. Such heating minimizes the temperature difference in the boiler and avoids the formation of condensation on the walls of the heat exchanger. This applies to a situation where one or two boilers have been turned off for a long time and have had time to cool down. If they have recently turned off, then the movement of the coolant before turning on the burner allows you to absorb the residual heat that is preserved in the firebox.
Piping boilers with cascade connection
Its scheme is as follows:
- 2–3 pairs of pipes extending from 2–3 boilers.
- Circulation pumps, check valves and shut-off valves. They are located on those tubes that are designed to return the coolant to the boiler. Pumps may not be used if the unit design includes them.
- Stopcocks on hot water supply pipes.
- 2 thick pipes. One is intended for supplying coolant to the network, the other for return. Corresponding tubes extending from the boiler devices are connected to them.
- Security group on the coolant supply line. It consists of a thermometer, a calibration thermometer sleeve, a thermostat with manual release, a pressure gauge, a pressure switch with manual release, and a reserve plug.
- Hydraulic separator low pressure. Thanks to it, pumps can create proper circulation of coolant through the heat exchangers of their boilers, regardless of what the flow rate of the heating system is.
- Heating network circuits with shut-off valves and a pump on each of them.
- Multi-stage cascade controller. Its task is to measure the coolant at the output of the cascade (often temperature sensors are located in the safety group area). Based on the information received, the controller determines whether to turn on/off and how the boilers combined into one cascade circuit should operate.
Without connecting such a controller to the piping, operation of boilers in a cascade is impossible, because they must work as a single unit.
Features of the scheme of primary-secondary rings
This scheme provides for the organization of a primary ring through which the coolant must constantly circulate. Heating boilers and heating circuits are connected to this ring. Each circuit and each boiler is a secondary ring.
Another feature of this scheme is the presence circulation pump in every ring. The operation of a separate pump creates a certain pressure in the ring in which it is installed. The assembly also has a certain effect on the pressure in the primary ring. So, when it turns on, water comes out of the water supply pipe, entering the primary circle and changing the hydraulic resistance in it. As a result, a kind of barrier appears on the path of coolant movement.
Since the return pipe is connected to the circle first, and after it the supply pipe, the coolant, having received considerable resistance at the supply pipe, begins to flow into the return pipe. If the pump is turned off, the hydraulic resistance in the primary ring becomes very small and the coolant cannot float into the boiler heat exchanger. The piping continues to work as if the disconnected unit did not exist at all.
For this reason, there is no need to use one complex automation system to turn off the boiler. The only thing that is needed is to install a check valve between the pump and the water return pipe. The situation is similar with heating circuits. Only the supply and return lines are connected to the primary circuit in the opposite order: first the first, then the second.
It is advisable to include no more than 4 boilers in such a scheme. Usage additional devices inappropriate.
Universal combined scheme
This system has the following harness:
- Two common collectors or hydraulic collectors. The first one is connected to the boiler supply lines. To the second - return lines. On all lines there is shut-off valves. There are circulation pumps on the coolant return pipes.
- Diaphragm tank connected to the large return manifold.
- The indirect heating boiler is the connecting link between two collectors. On the pipe that connects the boiler to the supply manifold, there is a circulation pump and shut-off valve. The pipe connecting the boiler to the return manifold also has a valve.
- The safety group is installed on the coolant supply manifold.
- The make-up pipe is connected to the manifold, which is located on the hot water supply line. To prevent leakage of hot coolant through this pipe, a check valve is installed on it.
- A certain number of small hydraulic collectors (there may be two, three or more). Each of them is connected to the above-mentioned common manifolds. These hydraulic reservoirs and large reservoirs form the primary rings. The number of such rings is equal to the number of small hydraulic collectors.
- The heating circuits depart from small hydrocollectors. Each circuit has a miniature mixer and circulation pump.
poluchi-teplo.ru
How to properly connect two boilers into one system in parallel
Modernizing the heating system in a private home may require installing two boilers at once, connecting them into a common network. What sequence should be followed? How to connect two boilers into one system, what must be taken into account if there is a need to share a gas boiler with a solid fuel, electric or heating equipment, running on liquid fuel. How to connect two boilers together?
I would like to clarify right away that it’s easy to connect two boilers to different types fuel into one system is one of possible solutions lack of power problems installed equipment. It is also possible to connect more than two models into one network. For what purposes may you need to connect two boilers to one system? There are several good reasons explaining the advisability of this.- Lack of power. Incorrect calculation of equipment or additional attachment living area can lead to the fact that the boiler power may simply not be enough to maintain normal coolant temperature.
- Increased functionality. It may be necessary to connect two boilers to one system to, for example, increase the time battery life equipment. For example, if the main source of heat is a solid fuel boiler, then for its operation it is necessary to constantly add firewood, which is not always convenient, much less practical. After installing an electric or gas boiler heating device, you can solve this situation as follows. As soon as the firewood or coal has burned out and the coolant has begun to cool, additional heating equipment is switched on in the process and continues to heat the room until the owner adds a new batch of firewood in the morning.
As you can see, connect two heating boilers on different types of fuel, this is practical, in addition, it may be due to an urgent need associated with a lack of equipment performance.
How to connect two gas boilers in parallel
There are two connection schemes for gas and any other water heating equipment. You can connect two boilers to one heating system:- Sequentially - in this case, one unit will be installed after another. In this case, the load will be distributed unevenly, since the main boiler will constantly operate at full capacity, which can lead to its rapid failure.
- Parallel. In this case, the heated area will be divided into two parts. Heating will be carried out by two installed boilers. Parallel connection of two gas boilers is usually used in cottage houses and buildings with a large heated area.
For parallel connection, it is necessary to install a controller and also develop a cascade control circuit. Only a competent specialist can answer the question of how to connect two gas boilers in each specific case.
How to connect two boilers - gas and solid fuel?
Combining gas and solid fuel boilers into one system is a simpler task, for which it is necessary to take into account the main features that distinguish the operation of these two types of equipment. Models of gas and solid fuel equipment can be installed in one network sequentially. In this case, TT boilers will play the role of the main source of heat supply. The principle of their operation will be that gas equipment will turn on for heating only if the operation of the main unit for some reason becomes impossible. Also, usually a gas boiler is assigned the task of heating water, of course, if such a function is provided. During the design of such a system, these features must be taken into account. It will also be necessary to agree on the chosen scheme in the gas sector and obtain all the necessary permits there, including technical specifications and connection project.How to combine gas and liquid fuel boilers
For safety reasons, such a connection must create conditions under which it is possible safe work two types of equipment at once. To do this you need to do the following:- Install a general work control system water heating equipment. The combined use of liquid fuel and gas boilers implies the installation of common automation. It, in turn, is connected to control sensors, which send a signal to turn on if the main heat source stops working.
- Install control valves. Shut-off valves operating in automatic mode can also be used.
Advantages of installing several boilers on one network
Connect two boilers at the same time: floor-standing and wall mounted boilers may be necessary if the area of the room as a result construction work, increased sharply. Even if the equipment was initially purchased with a power reserve, it may not be enough to heat additional rooms of a larger area. In this case, an additional boiler is installed, connected to common system heating. The advantage of this solution is:- Possibility of simultaneous control over the operation of all equipment.
- Savings due to the choice of the main type of fuel.
- Possibility of longer operation of equipment.
Practice shows that it is possible to simultaneously install two or more boilers in one network. With everyone additional element overall performance and efficiency drops significantly. Therefore, the feasibility of simultaneous installation of four or more units of water heating equipment is completely absent.
avtonomnoeteplo.ru
How do two boilers work in a heating system?
The creation of a heating circuit, in which two boilers in the heating system operate either individually or together, is associated with the desire to provide redundancy or reduce heating costs. The joint operation of boilers in an integrated system has a number of connection features that should be taken into account.
Possible options- two boilers in one heating system:
- gas and electricity;
- solid fuel and electricity;
- solid fuel and gas.
Combined operation of gas and electric boilers
Combining a gas boiler with an electric boiler in one circuit, resulting in a heating system with two boilers, can be implemented quite simply. Both serial and parallel connection are possible. In this case, parallel connection is preferable, because you can leave one boiler running while the other is completely stopped, turned off or replaced. Such a system can be completely closed, and ethylene glycol for heating systems or ordinary water can be used as a coolant.
Combined operation of a gas and solid fuel boiler
This is the most difficult option for technical implementation. In a solid fuel boiler it is extremely difficult to control the heating of the coolant. Typically, such boilers operate in open systems, And overpressure in the circuit when overheating is compensated in the expansion tank. Therefore, it is impossible to directly connect a solid fuel boiler to a closed circuit.
For the joint operation of a gas and solid fuel boiler, a multi-circuit heating system has been developed, which consists of two independent circuits.
The gas boiler circuit operates on radiators and on a common heat exchanger with a solid fuel boiler and an open expansion tank. For the room in which both boilers are installed, it is necessary to meet the requirements for both gas and solid fuel boilers
Combined operation of solid fuel and electric boilers
For such a heating system, the operating principle depends on the type of electric boiler. If it is intended for open heating systems, then it can be easily connected to an existing open circuit. If the electric boiler is intended only for closed systems, then the best option will be – joint work on a common heat exchanger.
Dual fuel heating boilers
To increase the reliability of heating and to avoid interruptions in the operation of the heating system, dual-fuel heating boilers are used, operating on different types of fuel. Combination boilers are manufactured only in a floor-standing version due to the rather large weight of the unit. A universal unit may have one or two combustion chambers and one heat exchanger (boiler).
The most popular scheme is the use of gas and firewood to heat the coolant. It should be taken into account that solid fuel boilers can only operate in open heating systems. To realize the advantages of a closed system, an additional circuit for the heating system is sometimes installed in the tank of a universal boiler.
There are several types of dual-fuel combi boilers:
- gas + liquid fuel;
- gas + solid fuel;
- solid fuel + electricity.
Solid fuel boiler and electricity
One of the popular combination boilers is a solid fuel boiler with an installed electric heater. This unit allows you to stabilize the temperature in the room. Thanks to the use of heating elements, such a combination boiler has gained mass positive qualities. Let's look at how the heating system works in this combination.
When the fuel in the boiler is ignited and the boiler is connected to the electrical network, the heating elements immediately begin to work, heating the water. As soon as the solid fuel ignites, the coolant quickly heats up and reaches the thermostat response temperature, which turns off electric heaters.
The combination boiler runs only on solid fuel. After the fuel burns out, the water begins to cool in the heating circuit. As soon as its temperature reaches the thermostat threshold, it will turn on the heating elements again to heat the water. This cyclic process will help maintain a uniform temperature in the rooms.
To optimize heating circuits, heat accumulators in heating systems were invented, which represent a large volume capacity from 1.5 to 2.0 m3. During operation of the boiler, a large volume of water is heated from the circuit pipes passing through the storage tank, and after the boiler stops operating, the heated water slowly releases thermal energy into the heating system.
Heat accumulators allow you to maintain a comfortable temperature for quite a long time.
To winter time To avoid critical situations, reduce heating costs and ensure its reliability, many owners prefer to either install a system with two boilers using different fuels, or install a universal dual-fuel boiler. These heating options have certain advantages and disadvantages, but their main task– stable and comfortable heating - they provide it fully.
spetsotoplenie.ru
What is connecting a solid fuel and gas boiler into one system?
Connecting a solid fuel and gas boiler into one system solves the issue of fuel for the owner. A single-fuel boiler is inconvenient because if you do not replenish reserves in a timely manner, you may be left without heating. Combination boilers roads, and if such a unit breaks down seriously, all the heating options provided for in it will become unfeasible.
Perhaps you already have a solid fuel boiler, but want to switch to another one that is more convenient to use. Or the existing boiler does not have enough power, you need another one. In any of these cases, you will need to connect a solid fuel and gas boiler into one system.
Features of connecting two boilers
Connecting two boilers to one heating system creates difficulty in combining them: gas units are operated in closed system, solid fuel - in the open. Open harness The TD of the boiler allows you to heat water to a temperature of over 100 degrees, at a critically high pressure value (what is the piping of a solid fuel boiler).
To relieve pressure, such a boiler is equipped with an open-type expansion tank, and elevated temperatures are dealt with by releasing part of the hot coolant from this tank into the sewer. When using an open tank, airing of the system is inevitable; free oxygen in the coolant leads to corrosion of metal parts.
Two boilers in one system - how to connect them correctly?
There are two options:
- sequential scheme for connecting two boilers into one heating system: a combination of open (TD boiler) and closed (gas) sector of the system using a heat accumulator;
- installation of a solid fuel boiler in parallel with a gas boiler, with safety devices.
A parallel heating system with two boilers, gas and wood, is optimal, for example, for a cottage with a large area: each unit is responsible for its own half of the house.
In this case, a controller and cascade control capability are required. At sequential circuit Connecting gas and solid fuel boilers into one system results in two independent circuits connected by a heat accumulator (what is a heat accumulator for heating boilers).
Any boiler room is the heart of the system and. In this article I will tell you how to assemble a boiler room so that it at least has a well-functioning heating and water supply system. Using these algorithms, you can maximize the effect of the system.
Video:
I will teach you how to make calculations and assemble such a heating system.
In this article you will learn:
Who plans to let you down natural gas V boiler room, you need to familiarize yourself with the requirements for boiler houses with gas boilers.
Any heating project where it is planned to heat a house begins with calculating the heat losses of a given house. SNiPs, GOSTs and various literature have been developed on how to calculate houses for calculating heat losses. One of the SNiPs is SNiP II-3-79 “Construction Heat Engineering”.
I want to talk a little about thermal calculations. In fact, heat calculation is not carried out by some instruments, as some may assume. Any engineers at the design stage use pure or theoretical science, which allows, through only known materials from which the house is made, calculate the lost heat. Many engineers use special programs to speed things up, one of which I personally use.
The program is called: "Valtec Complex"
This program is absolutely free and can be downloaded on the Internet. To find this program, simply use the search in Yandex and enter the search line: “Valtec Complex program.” If you do not find this program on the Internet, then contact me and I will tell you the direct address. Just write in a comment on this page and I will answer there.
Solution.
A universal formula is used to solve:
W - energy, (W)
C - heat capacity of water, C = 1163 W/(m 3 °C)
Q - flow rate, (m 3)
t1 - Cold water temperature
t2 - Hot water temperature
Just insert our values, do not forget to take into account the units of measurement.
Answer: Each person needs 322 W/hour.
This type of filter filters out large particles in order to prevent clogging in the boiler. A boiler with such a filter will last much longer than without it.
Also installed on the return line. But they often put him on the service line.
The first reason why we install a check valve on the return line of the heating system.
The check valve is used to prevent the reverse movement of the coolant in cases where two boilers are installed in parallel. But this does not mean that it does not need to be placed on the return line when one boiler is installed.
For the second reason a check valve is placed on the supply line in order to prevent reverse movement of the coolant in order to prevent debris from entering the heating system through the supply line.
How to connect two boilers
Maximum connection level for two boilers with valves
Advantages of working two boilers in pairs
If one boiler fails, the heating system will continue to operate.
There is no need to buy one powerful boiler; you can buy two weak boilers.
Two weak boilers working together produce much more heated coolant, since some powerful boilers have a small passage diameter. Due to the small passage diameter, the coolant flow through the boiler, to put it mildly, remains insufficient for big house. Although there are schemes that allow you to increase consumption. We'll talk about this below.
Disadvantages of two working boilers in pairs
The cost of two weak boilers is much higher than one powerful boiler.
It would not be justified to operate two pumps. Although two pumps can operate in quite economical mode than one set at high speeds.
Regarding the selection of pipe diameter
As far as I know, there are three ways to determine:
The philistine way- this is the selection of diameter by determining the speed of water movement in the pipeline. That is, the diameter is selected so that the speed of water movement does not exceed 1 meter per second for heating. And for water supply, more is possible. In short, we saw it somewhere and copied it, repeating the diameter. They also find all sorts of recommendations from specialists. Some average is taken into account. In short, the philistine method is the least economical and allows for the most serious mistakes and violations.
Practice-proven- this is a method in which schemes are already known and special tables have been developed, which already contain all the diameters and indicate additional parameters for water flow and speed. This method is usually suitable for dummies who do not understand calculations.
The scientific method is the most ideal calculation
This method is universal and makes it possible to determine the diameter for any task.
I watched a lot of training videos and tried to find calculations for determining pipeline diameters. But I couldn’t find a good explanation on the internet. Therefore, for more than 1 year, my article on determining the diameter of a pipeline has existed on the Internet:
And some even use special programs for hydraulic calculations. Moreover, I even found incorrect and unqualified hydraulic calculations. Which are still circulating on the Internet and many continue to use an unreasonable method. In particular, the hydraulics of heating systems are considered incorrectly.
For precise definition diameter you need to understand the following:
Now attention!
The pump pushes the liquid through the pipe, and the pipe with all its turns provides resistance to movement.
The pump force and resistance force are measured by only one unit of measurement - meters. (meters of water column).
To push liquid through a pipe, the pump must cope with the force of resistance.
I have developed an article that describes in detail:
Any pump has two parameters: Pressure force and flow rate. Therefore, all pumps have pressure-flow graphs, which show along the curve how the flow rate changes depending on the resistance of fluid movement in the pipe.
To select a pump, you need to know the resistance created in the pipe at a certain flow rate. You must first know how much liquid will need to be pumped per unit of time (flow rate). At the indicated flow rate, find the resistance in the pipeline. Next, the pressure-flow characteristic of the pump will show whether such a pump is suitable for you or not.
In order to find resistance in a pipeline, the following articles have been developed:
At the design stage, you can find the flow rate of the entire system, just know heat losses a certain building. This article describes an algorithm for calculating coolant flow for certain heat losses:
Let's consider a simple problem
There is one boiler and a two-pipe dead-end. See image.
Pay attention to the tees, they are designated by numbers... When explaining, I will indicate this: Tee1, tee2, tee3, etc. Also note that the costs and resistances in each branch are indicated.
Given:
Find:
| Pipe diameters of each branch Select the pump pressure and flow rate. |
Solution.
Find the total consumption of the heating system.
Let us assume that the temperature of the supply line is 60 degrees, and the return line is 50 degrees.
then, according to the formula
1.163 - heat capacity of water, W/(liter °C)
W - power, W.
where T 3 =T 1 -T 2 is the temperature difference between the supply and return pipelines.
The temperature difference is set from 5 to 20 degrees. The smaller the difference, the greater the flow rate and, accordingly, the diameter increases. If the temperature difference is greater, the flow rate decreases and the pipe diameter may be smaller. That is, if you set the temperature difference to 20 degrees, the flow rate will be less.
Find the diameter of the pipeline.
For clarity, it is necessary to bring the diagram into block form
Since the resistance in the tees is very small, it should not be taken into account when calculating the resistance in the system. Since the resistance of the length of the pipe will be many times greater than the resistance in the tees. Well, if you are a pedant and want to calculate the resistance in the tee, then I recommend that in cases where the flow rate is greater for a 90-degree turn, then use an angle. If it is less, then you can close your eyes to it. If the coolant moves in a straight line, then the resistance is very small.
| Resistance1 = branch 1 from tee2 to tee7 Resistance2 = radiator branch2 from tee3 to tee8 Resistance3 = radiator branch3 from tee3 to tee8 Resistance4 = branch 4 from tee4 to tee9 Resistance5 = radiator branch5 from tee5 to tee10 Resistance6 = radiator branch6 from tee5 to tee10 Resistance7 = path from tee1 to tee2 Resistance8 = pipe path from tee6 to tee7 Resistance9 = pipe path from tee1 to tee4 Resistance10 = path from tee6 to tee9 Resistance11 = pipe path from tee2 to tee3 Resistance12= pipe path from tee8 to tee7 Resistance13 = path from tee4 to tee5 Resistance14= pipe path from tee10 to tee9 Resistance of the main branch = from tee1 to tee6 along the boiler line |
For each resistance it is necessary to select a diameter. Each resistance section has its own flow rate. For each resistance it is necessary to set the declared flow rate depending on the heat losses.
We find the costs at each resistance.
To find the flow rate in resistance1, you need to find the flow rate in radiator1.
Calculation of diameter selection is carried out cyclically:
Further calculations for this problem are included in another article:
Answer: Optimal minimum consumption equal to: 20l/m. At a flow rate of 20 l/m, the resistance of the heating system is: 1m.
Of course, it is still necessary to take into account the resistance of the boiler, which can be taken to be approximately 0.5 m. Depending on the passage diameters of the boiler itself. In general, to be more precise, it is necessary to calculate in the boiler itself through the tubes. How to do this is described here:
How to wire a water heating system for a very large house
There is a universal scheme for water heating systems, which allows you to make the system more advanced, functional and very productive.
Above I already explained why such elements are needed:
Hydroarrow- this is actually a hydraulic separator, a detailed explanation and calculation of the hydraulic arrows is explained here:
But I will repeat myself a little and explain some more details. Let's consider a circuit with a hydraulic separator and a manifold together.
V1 and V2 should not exceed a speed of 1 m/s; as the speed increases, unjustified resistance occurs at the inlet and outlet of the pipes.
V3 should not exceed a speed of 0.5 m/s; as the speed increases, resistance from one circuit to another is influenced.
F - The distance between the pipes is not regulated and is taken as minimal as possible in order to comfortably connect various elements(100-500mm)
R- The vertical distance is also not regulated and is accepted as a minimum of 100mm. Maximum up to 3 meters. But the distance (R) of the diameters of the four pipes (D2) would be more correct.
The main purpose of the hydraulic arrow is to obtain an independent flow rate that will not affect the boiler flow rate.
The main purpose of a collector is to split one stream into many streams so that the streams do not affect each other. That is, so that a change in one of the collector flows does not affect other flows. That is, a very slow movement of coolant occurs in the collector. Slow velocity in the reservoir has less effect on the flows leaving it.
We disassemble the inlet diameter from the boiler D1
One of the calculations of diameter is this formula:
It is necessary to strive for the minimum speed of coolant movement. The faster the coolant moves, the higher the resistance to movement. The greater the resistance, the slower the coolant moves and the weaker the system heats.
Task.
Let's try to increase the diameter to 32mm.
Then the schedule will be like this.
Maximum flow rate 29 l/m. The difference from the original is 4l/m.
It's up to you to decide whether the game is worth the trouble... Further increase will lead to a pointless waste of money on large diameters.
Next, I take into account that each boiler will have a flow rate of 29 l/m. the flow rate from two boilers will be 58 l/m. Now I want to calculate what diameter to choose for the pipe that connects two boilers and goes into the hydraulic valve.
Finding the diameter after the tee
Given:
At a flow rate of 58 l/m, the resistance was: 0.85 m, basically the resistance creates about 0.7 m. To reduce the resistance of the mud filter, it is enough to increase its diameter or the thread on it. The greater the permeability of the mud filter, the less resistance it contains.
Therefore, we make a decision: Do not increase the diameter, but increase the mud filter, with a thread of up to 1.5 inches.
With this effect, we will significantly increase the total heat flow from the boiler to the water gun.
Also, by this effect of increasing the flow through the boiler, we increase the efficiency of the boilers.
Also if we want to reduce the resistance check valve, then the thread on it should be increased. Therefore, we accept a 1.25-inch thread.
Ball valves should be selected in such a way that the internal passage does not narrow or increase, but exactly repeats the passage itself. Choose a passage in the direction of increasing diameter.
More information about hydraulic shooters:
According to the problem:
Heated floor consumption: 3439 l/h at a temperature difference of 10 degrees.
400m2 x 100W/m2 = 40000W
Regarding radiator heating, operating principle various schemes. I have not yet prepared articles on this topic, since most people know how to do it, at least approximately. But there are plans to touch upon this topic and prescribe strict laws and calculations for the development of circuits in space.
Regarding warm water floors
The diagram shows that warm water floors are connected through. The circuit forms through a three-way valve.
Mixing unit- this is a special pipeline chain that forms the mixing of two different flows. IN in this case For this purpose, two flows are mixed: the heated coolant from the collector and the cooled coolant returned from the heated floors. Such mixing, firstly, gives a lower temperature, and secondly, adds flow to the heated floors. Additional expense accelerates the flow of coolant through the pipes.
I also prepared a special video about how a three-way valve based on a servo drive works:
The most the perfect way The element used to remove air automatically is: Automatic air vent. But to use it effectively, it must be installed on the highest supply pipe of heating systems. In addition, you need to create an area of space in which the air will be separated.
See diagram:
That is, the coolant leaving the boiler must first rush upward to the air separation system. The air separation system consists of a tank with a thickness 6-10 times greater than the diameter of the pipe entering it. The air separator tank itself should be at its highest point. There should be a .
The inlet pipe should be at the top, and the outlet pipe should be at the bottom.
When the coolant has low pressure, gases begin to be released in it. Also, the hottest coolant has a more intense gas release.
That is, by pushing the coolant to the very top, we reduce its pressure and thereby the air begins to be released more intensely. Since the coolant immediately going into the air separator tank has the highest temperature and, accordingly, gas release will be intense.
Therefore, for ideal air release in a heating system, two conditions must be met: high temperature and low pressure. And low pressure is at its highest point.
For example, you can try installing a pump after the air separator tank, thereby reducing the pressure in the tank.
And why is this method of air release not used everywhere?
This method of releasing air has long been known!!! In addition, it greatly reduces the hassle of releasing air.
How to connect a solid fuel boiler
As you know, solid fuel boilers are at risk of overheating due to failure of the air shut-off mechanisms. For safe use Solid fuel boilers for high temperature heating systems use two main elements.
How a capacitive hydraulic separator works is described here:
Why are they dangerous? high temperatures for heating systems?
If you have plastic pipes such as polypropylene, metal-plastic, etc., then direct connections of such pipes to a solid fuel boiler are contraindicated.
The solid fuel boiler is connected only with steel and copper pipes, which can withstand temperatures over 100 degrees.
Pipes that can withstand high temperatures are assembled with temperature restrictions.
Three-way valves are mainly used with large bores and servo actuators. with mechanical movement of valves they have a very narrowed flow area, so check out the flow charts for these three-way valves.
The three-way valve in the boiler circuit serves to prevent low temperature With . Such a three-pass valve must allow the coolant to flow into the boiler at least 50 degrees.
That is, if the heating system is below 30 degrees, it begins to open the boiler circuit inside the boiler itself. That is, the coolant leaving the boiler immediately enters the boiler on the return line. If the boiler temperature is above 50 degrees, cold coolant begins to flow from (from the tank). This is necessary in order not to cause a strong temperature overload in the boiler circuit, since a large temperature difference causes condensation on the walls of the heat exchanger, and also reduces the favorable annealing of the firewood. In this mode, the boiler will last longer. Also, ignition of the boiler will be faster and more efficient than if the boiler were constantly supplied with ice coolant.
The temperature of the solid fuel boiler must be at least 50 degrees. Otherwise, you need to reduce the temperature of the three-way valve not 50, but below degrees to 30.
With low heating temperatures of 50 degrees, you need to take into account the decrease in temperature of the three-way valves. If you set the boiler to 50 degrees, then three way valve set the boiler circuit to 20-30 degrees, and at the outlet to 50 degrees. Also keep in mind that the higher the temperature pressure in the boiler, the higher the efficiency of the boiler. That is, a cooler coolant should flow into the boiler. Also, the greater the flow through the boiler, the higher the efficiency of the boiler. This is evidenced by heating engineering.
The flow rate through the boiler should be as high as possible for effective heat exchange (higher efficiency).
A three-way valve at the outlet to the heat consumer is needed in order to stabilize the temperature of the consumer and prevent high temperatures from entering.
Let's consider heating systems consisting of a Gas boiler and an Electric boiler. Why are such systems installed? There are several options here, or to duplicate the heating system, if it fails for some reason, the consumer will be able to use another one. But in most cases, the installation of an electric boiler is used for use at night, when the electricity tariff is minimal, subject to a formalized tariff for electric heating and the presence of a 2-tariff electricity meter. The economic benefit when using an electric boiler at night is 2.52 times. If electric heating is used as an auxiliary system.
Comparing performance and cost electric heating with gas.
If the efficiency of electric boilers is about 98%, then the majority of gas boilers have an efficiency of about 90%, with the exception of condensing boilers, which have an efficiency of more than 100%. However, it is worth taking into account that when calculating the efficiency of most gas boilers (especially imported ones produced in Germany, Italy and others), the calorific value of gas was taken into account of about 8250 kcal per 1 cubic meter of gas. However, in the current situation, gas is supplied via a mixed system. The minimum calorie content of mixed gas should not be lower than 7600 kcal. As practice shows, many gas consumers during the heating season state that the gas supplied to them is significantly lower than 7600 kcal. Therefore, with low-calorie gas, the efficiency of branded gas boilers will be as stated by the manufacturer.
In calculations we will use the caloric value of gas as 7600 kcal, since this is the minimum permissible calorie content according to existing legislation. If we compare the calorific value of gas and electricity at efficiency equal We will get 100%
7600 kcal = 8.838 kW = 1 cubic meter of gas.
In practice, 100% can only be obtained by condensing boilers, all others will actually work 82% or less. That is, when using low-calorie gas to generate 7600 kcal of heat, you will have to spend not 1 cubic meter of gas, but 1.18 cubic meters of gas.
If electric heating use as an auxiliary system.
| 7600 kcal | Fuel | Efficiency % | Consumption | Price | Bottom line | Benefit |
| Gas | 82 | 1.18 cc | 6,879 | 8,11 | 2.52 times | |
| Electro | 98 | 9.014 kW | 0,357* | 3,217 |
*In the calculation, we used a tariff of 0.357 UAH per 1 kW, provided that a tariff for electric heating was issued, and the main load on the boiler falls from 23.00 to 7.00, and electric heating acts as an additional system.
What you need to pay attention to when installing an electric boiler, when installing it in existing system heating, where the main source of heating was a gas boiler.
Fig. 1 Series connection diagram of the T c electric boiler gas boiler without a built-in security group and expansion tank. KE1 - electric boiler, KG1 - gas boiler without a built-in safety group and expansion tank, BR1 - expansion tank, RO - heating radiators, V - shut-off valves, VR - control valves, KZ1 - relief valve, PV - automatic air deaerator, M1 - pressure gauge, F1 filter.In most cases, each heating system is unique. Very often, the consumer has a gas boiler installed as a single module, i.e. circulation pump and expansion tank are already installed in the boiler. Many installers very often offer to save your money and offer to install an electric boiler in series, i.e. both boilers operate in a common flow. The meaning of saving is that you will be offered to purchase a cheap boiler that does not have an expansion tank or a circulation pump. Such an electric boiler will indeed be cheaper than a fully equipped one. Many people agree to such an offer without much thought. However, this is a dubious method of saving, since most of the functions with such a scheme are carried out by the gas boiler, and in the event of an emergency stop of the gas boiler, for example, failure circulation pump, or expansion tank, etc., etc. The entire system will stop.
On the one hand, you have two sources for heating, and on the other hand, you are highly dependent on the performance of the gas boiler. Conclusion - a series connection of an electric boiler will not always provide you with complete comfort.
The second method of installing an electric boiler in a heating system with a gas boiler is a parallel installation.
This installation method is considered the most correct, since you get two independent heating sources and if one fails, you can fully use the other. With a slightly larger initial investment, you will receive the most reliable and comfortable heating system.
