Let's start with what's in modern house located in the middle lane, there should be 2 boilers. It is not even necessary 2 boilers, but two independent sources of heat energy - that's for sure.
We have already written about what kind of boilers or energy sources they can be in the article "". It describes in more detail which boiler, which backup is needed and can be selected.
Today we will consider how to connect 2 or more heat generators to a single heating system and how to connect them. Why am I writing about 2 or more units of heating equipment? Because there can be more than 1 main boiler, for example, two gas boilers. And also there can be more than 1 reserve boiler, for example, on different types fuel.
Let us first consider a scheme in which we have two or more heat generators, which are the main ones and, heating the house, operate on the same fuel.
These are usually connected in a cascade in order to heat rooms from 500 sq.m. total area. Rarely enough they are connected together for main heating or solid fuel boilers.
We are talking specifically about the main heat generators, and about the heating of residential premises. For cascade and modular boiler houses for heating large industrial premises can include "batteries" of coal or fuel oil boilers in an amount of up to one dozen.
So, as mentioned above, they are connected to a cascade when a second identical boiler or slightly less power complements the first heat generator.
Usually in the off-season and light frosts, the first boiler in the cascade works. In frosts or if it is necessary to quickly warm up the premises, the second boiler in the cascade is connected to help it.
In a cascade, the main boilers are connected in series so that it is heated by the first heat generator. At the same time, of course, in this bundle it is possible to isolate each boiler and bypass, which allows water to bypass the isolated boiler.
In the event of a malfunction, any of the heat generators can be turned off and repaired, while the second boiler will regularly heat the water in the heating system.
There is no particular alternative to the system. As practice shows, it is better and more reliable to have 2 boilers with a capacity of 40 kW than one boiler with a capacity of 80 kW. This makes it possible to repair each individual boiler without stopping the heating system.
It also allows each of the boilers to operate at their full capacity when required. Whereas 1 boiler of high power would work only at half the power and with increased stroke.
We examined the main boilers above. Now let's consider the connection of backup boilers, which should be in the system of any modern home.
If backup boilers are connected in parallel, then this option has its pros and cons.
The advantages of parallel connection of reserve boilers are as follows:
Disadvantages of parallel connection of reserve boilers:
The indicated advantages and disadvantages of parallel connection can be applied both to the connection of the main and backup heat generator, and to the connection of two or more backup heat generators using any type of fuel.
If two or more boilers are connected in series, they will operate in the same way as the main boilers connected in a cascade. The first boiler will heat the water, the second boiler will heat it up.
In this case, the first is to put the boiler on the cheapest type of fuel for you. It can be wood, coal or waste oil boiler. And behind it in the cascade there can be any reserve boiler - even a diesel one, even a pellet one.
The main advantages of parallel connection of boilers:
Cons when using a parallel method of connecting backup heat generators in the boiler room:
Naturally, you cannot directly start up the supply from one boiler to the inlet of another. In this case, you will not be able to disconnect either the first or the second boiler, if necessary.
Although from the point of view of coordinated heating of boiler water, this method will just be the most effective. It can be realized if bypass bypass loops are installed for each boiler.
And here is a couple of reviews from users about the parallel and serial connection of heat generators in the heating system:
Anton Krivozvantsev, Khabarovsk Territory: I have it, it is the main one and heats the entire heating system. I am satisfied with Rusnit, a normal boiler, for 4 years of operation 1 heating element burned out, I changed it myself, there are all business for 30 minutes with a smoke break.
A KChM-5 boiler is connected to it, into which I built it. The steam locomotive turned out to be a noble one, heats well and, most importantly, the automation of the process is almost the same as that of an automatic pellet boiler.
These 2 boilers work in pairs for me, one after the other. The water that Rusnit did not heat is followed by KChM-5 and the pellet burner Pelletron-15. The system turned out as it should be.
There is one more review, now about the parallel connection of 2 boilers in the boiler room:
Evgeny Skomorokhov, Moscow: My main boiler is, it runs mainly on wood. My reserve boiler is the most common DON, which is included in the system with the first in parallel. It is rarely kindled, and indeed, I inherited it along with the house I bought.
But once or twice a year, in January, the old DON also has to be flooded, when the water in the system almost boils, but the house is still chilly. This is all due to poor insulation, I have not yet finished insulating the walls, and it would be good to insulate the attic ceilings better.
When the insulation is completed, I think I will not heat the old DON boiler at all, but I will leave it as a backup.
If you have any comments on this material, please write them in the comments form below.
It is not a secret for anyone that the centralized supply of heat to existing and newly constructed facilities becomes more and more problematic every year. In particular: the lack of the possibility of objective accounting, large losses of heat during transportation, subjectivity in determining the cost, the monopolistic nature of the activities of heat suppliers, the impossibility of increasing the existing capacity, and, consequently, the ban on connecting additional consumers - these are just some of the problems due to which the views of specialists turn to the side autonomous heating and hot water supply.
In this regard, in recent years in our country, block boiler houses, modular boiler houses or cascade boiler houses have become increasingly popular.
The Termona-Bel company promotes in the domestic market heating equipment The Czech company Thermona (Thermona), which has been working for many years in the direction of improving equipment for autonomous heating. One of the first in the world, the specialists of Thermona (Thermona) 13 years ago came up with the idea of creating cascade boiler houses on the basis of wall-mounted gas boilers with a capacity of 8 to 1440 kW.
A cascade based on THERM boilers is a series connection of several boilers (up to 16 units) into a single heating system with program control. The peculiarity of the connection and design of Therm boilers allows smooth regulation of the total power of all boilers in the cascade from the minimum power of one of the boilers. For example, when installing a cascade of 16 THERM TRIO 90 boilers, the total boiler room power will be 1440 kW, and the minimum - 36 kW, i.e. 2.5% of her maximum. For comparison, a modern boiler with a capacity of 1500 kW provides a regulation range from 1050 kW to 1500 kW, which is from 70 to 100% of the power.
In technology heating systems cascade boiler room based on THERM boilers is an innovative method for optimizing the operation of heating systems with high power. It is quite obvious that the heat loss of the facility, and, accordingly, the power of the boiler house is calculated based on the lowest temperatures in the region, and the actual load on the boiler house is much lower than the established one.
Practice has confirmed that during the heating season, approximately 80% of the operating period, the capacity of the boiler house is used no more than 50%, and during the operating season, the load is, on average, 25-45%. Consequently, with such an uneven and often low load, one large-capacity boiler (traditional system) will unnecessarily consume energy and ineffectively compensate for heat costs. In contrast to this, the cascade system smoothly ensures the operation of the boiler house at the required power (in a wide range) regardless of the season by connecting several small boilers in series one after the other. With the help of cascade control with programmed control, the problem of determining the optimal ratio of the power of the boiler room and the heating system is solved. Thus, in the off-season and during warm winters, a cascade boiler house can operate for a long time at low temperatures coolant, which reduces the cost of heat radiation and periods of standby modes of the system. At the same time, temperature conditions object, that is, the comfort of the user.
The use of THERM DUO, TRIO and KD boilers in a cascade allows you to achieve an optimal ratio of the occupied area to the installed power of the boiler room while maintaining one of the main advantages of cascade connection - an incomparably wide range of smooth power modulation. In the organization of the boiler room, single-circuit wall-mounted boilers with a capacity of 20, 28, 45 and 90 kW. It is possible to assemble in a cascade from 2 to 16 units, depending on the required power. All boilers are modern, technically advanced gas appliances with an efficiency of up to 94%, with a service life of at least 15-20 years.
A significant advantage of a cascade boiler house based on THERM boilers over traditional boiler houses is its high reliability and increased service life. The high reliability of the boiler room is achieved due to the joint operation of several boilers in one system, moreover, the failure of one of the boilers does not stop the operation of the heating system as a whole. The software underlying the operation of the cascade boiler house is designed in such a way that the sequence of starting the boilers changes every day. Therefore, if today the boiler starts up first, then the next day it becomes the last in the queue and it will start up only if it is necessary to operate the boiler room at full capacity. Due to this, the service life of each boiler increases, which leads to an increase in the service life of the boiler house as a whole. An undoubted advantage in a cascade boiler room is the ability to connect an indirect heating boiler to each boiler (with the exception of the manager). Thus, in a boiler room of 16 boilers, 15 boilers from 200 to 1000 liters each can be connected and thereby satisfy any need for hot water supply. The boiler automation gives preference to the preparation of hot water supply, and if there is no need for its preparation, the boiler switches to work in the heating system together with other boilers. When the cascade boiler room switches from winter to summer operation, the DHW preparation mode remains, the heating system pumps automatically start once a day, driving the coolant through the system, and the anti-freeze function remains active. The advantages of the cascade connection of boilers, undoubtedly, include the possibility of choosing a variety of boiler room options: location and placement. You can install the boiler room almost anywhere: in the basement or attic, in a specially made extension.
In the case of organizing a boiler room on the roof, a huge advantage of a cascade of wall-mounted boilers over stationary floor-standing boilers is their low weight and ease of delivery to the installation site. There is no need to use special cranes for lifting equipment during installation or dismantling. There is no need to dismantle the roof when replacing the boiler. Defective boiler components are replaced on site. The low weight of the equipment and its placement on the wall - allow you to avoid unwanted loads on the floors of the building. Diversion flue gas when using boilers in the "turbo" version, it is possible directly through the wall on which the boiler is mounted. This saves on the construction of an expensive stainless steel chimney. An indisputable advantage is the automatic regulation of the boiler room. The programmer provides control in accordance with the room temperature set for a given period of time. He attracts to work the required number of boilers from the cascade and at such a power that is really needed. The absence of a "human factor" excludes mistakes in management. In general, a universal building climate control system is being created. When the temperature in the room rises above the set one, the programmer turns off the operation of the boiler room, and if necessary, the thermostat of the air conditioning system turns on the air conditioning system. In the case of a decrease in temperature, everything happens in the reverse order. Boiler room control devices allow the dispatcher of the service organization to see the current state of all equipment from his computer via a modem.
Thermona-Bel company is official dealer of the Czech company Thermon on the territory of the Republic of Belarus. The main activities of the Termona-Bel company are wholesale and retail trade in boiler houses, training of interested specialists, installation and commissioning of boilers, warranty and service maintenance boiler houses, supply of spare parts for boilers and other activities aimed at promoting equipment in the territory of the Republic of Belarus.
Briefly, the main advantages of cascade boiler houses based on THERM boilers can be formulated as follows:
profitable investment;
economical operation due to a wide range of smooth power modulation (the minimum threshold is from 20% when installing 2 boilers and from 3% when installing 16 boilers);
full automation of management;
weather-dependent regulation;
remote control and management of the boiler room through a programmer or PC;
no need to keep full-time employees in the boiler room;
high operational reliability due to the operation of several boilers in one system;
increased service life of boiler equipment;
simplicity and clarity technical solution;
ease of installation and commissioning;
simple and intuitive control;
small area of the occupied space;
use of the floor for other components of the boiler room;
convenient connection of external tanks for the preparation of hot water supply;
the possibility of installing a high-power boiler room without an expensive chimney;
respect for environment.
Right choice a heat source can save a lot of money while maintaining the required comfort. When comparing the economic indicators of the operated residential buildings and other sites, before and after Therm cascade systems are installed, users often achieve incredible energy savings of up to 40% per year, so the return on investment is very fast and obvious!
As a rule, gas boilers in private houses are connected to the same circuit. But, this connection method has its drawbacks. Much more effective when the system is the use of multiple devices. The very same boiler piping scheme in this case can be cascade.
When gas boilers are connected to the heating circuit in series and form stage by stage, this is very convenient. At the same time, the control of the cascade cycle is general, and the owner can independently adjust the system parameters based on the conditions. While the rest of the parameters are adjusted automatically. Experts call this method of customization flexible.
Gas boilers connected on a cascade principle can be used to solve problems of heating residential buildings with a total area of not more than 500 square meters. And although these figures are not mandatory for use, the owner independently decides the advisability of installing an additional boiler if the area to be heated is larger.
In any case, gas boilers connected according to the cascade principle are very efficient to use. Those who installed them will be able to feel it very soon.
If you plan to connect gas boilers with a cascade type, you will need to independently determine the optimal scheme and calculate its parameters, taking into account all professional assessments important factors... For example, turning on boilers can be possible in a sequential way, without additional equipment, only if the pump of each gas boiler is able to pump the coolant through the heating circuit. For a residential building of a small area, this is quite enough.
But, if gas boilers are used for a large building consisting of several floors, then it is imperative to use a special hydraulic divider. This will optimize financial costs, guarantee higher comfort and rational consumption of blue fuel.
Connecting the circuit to only one heating device (the most common way of heating private houses) has its drawbacks. If several units are installed in the system (and not necessarily the main ones; we can talk about redundancy by two or more units on different types of fuel), then this gives a lot of advantages. There are various piping schemes for boilers (including gas ones), one of which is called cascade.
What is the peculiarity of this engineering solutions? All heat generators are connected to the heating circuit sequentially, that is, each of them represents one stage of it. But the control of the cascade is general, and the user can configure all the parameters of the system himself, depending on local conditions, and the automation will do the rest. This type of regulation is called “flexible”.
In what cases is it worth making a series connection of boilers? It is considered that in relation to residential buildings in which the total heated area is not less than 500 m 2. But this is not an axiom, and the owner has the right to determine himself the advisability of installing two (or more) units with their cascade connection to the system.
This scheme is the most effective (subject to certain conditions) and simple to execute. Sometimes it is much more profitable to purchase and mount exactly 2 (or 3) wall gas models medium (or even low) power, than to look for a separate room, to equip the foundation for one dimensional floor-standing boiler. For example, if the heating circuit provides heat not only to the house, but also to outbuildings - a shed, garage, greenhouse, and so on. There are more than enough options when the capabilities of one installation do not allow providing high-quality heating of the dwelling - the specifics of the climate, unfavorable location houses on the ground, illiterate thermal insulation of walls, deterioration of the building, and so on.
Are there any peculiarities of cascading connection? It is difficult to independently choose the optimal scheme, all the more to calculate all its parameters. This requires a professional assessment of all factors. Gas boilers can be switched on in series without additional devices only if the pump of each unit is capable of "pumping" the coolant along the entire circuit. As a rule, this is quite enough for a small private residential building.
But if the system is assembled according to a complex scheme, the building is oversized, several stories high, and you cannot do without a hydraulic divider (it is often called an “arrow”). In this case, another pump with a higher capacity is installed in the secondary circuit (load).
In order for the cascade to work as efficiently as possible, it is advisable to use two temperature sensors (internal and external) and an electronic controller in the system. The additional costs will pay off pretty quickly, not only in terms of comfort, but also at the expense of more.
Can all boiler models be combined in a cascade? No, and this is one of the difficulties. This possibility primarily depends on the features of the automation of gas units. If we analyze the reviews on thematic forums, then for a consistent inclusion the owners of private buildings are mainly guided by the German wall-mounted boilers of the Viessmann brand. With them, according to users, it is somewhat easier.
WITH lineup heating appliances"Viessmann", which are advisable to use for cascades, and their prices can be found. But these are not the only boilers that can be turned on in series. Baxi, Protherm, Vaillant, Buderus have proven themselves quite well in such schemes.
What is the advantage of cascading boilers? One of the main questions that most buyers ask. After all, the traditional scheme with one unit, radiators and pipes is a kind of stereotype, and a person who does not have special training, it is difficult to understand all the advantages of a cascade connection. Moreover, these are additional costs, and it is not known whether it is worth making everything so complicated.
That is why prudent owners always solve the problem of heating redundancy. With a cascade connection, it is leveled, since if necessary, any of the boilers can be temporarily excluded from the circuit (for maintenance or repairs) without compromising the quality of heating the house.
If you live in the Moscow region and come to the conclusion that the cascade connection of gas boilers is the best solution for your home, call 8 495 3084648. The specialists of the ALFATEP company will give a professional answer to any incomprehensible question. If the client wishes, they will draw up a project of the system, select necessary equipment, they will assemble it themselves, test it in operation and hand it over to the customer on a turnkey basis. In parallel, they will teach you how to correctly configure and control the cascade.
One of the first to organize the operation of boilers according to a cascade scheme was developed and implemented by Thermona company from the Czech Republic. Then, seeing the undeniable economic benefit from the use of cascades, this principle of joint use of several wall-mounted gas boilers (mainly condensing) was applied by companies such as Viessmann, Baxi, etc.
So what is a "cascade of boilers"
It is necessary to understand the difference between a cascade of boilers and their parallel connection, where each of the boilers works separately, but into one heating system (ventilation, etc.). These are completely different schemes. The cascade is a joint hydraulic and electrical connection several boilers, united by a single control system, and working to provide heating of the heat carrier for the same object.
There are cascade connections, where control is carried out by means of smooth power modulation - from the minimum one of the boilers to the maximum power of the entire boiler room (as, for example, in the same Thermona). There is another approach - controlling the operation of boilers by means of a cascade switch, which, during operation, turns off several boilers or turns them on without using the possibility of their individual modulation.
But, in any case, this is a system under a single control that receives data on the required temperatures - the "supply" of heating and room, and also has the ability to work using the data of the outside temperature sensor, that is, it is much more flexible and economical than one boiler or parallel switching on a group of boilers. In heating technology, the cascade system is a truly innovative method for optimizing high power systems.
Instead of one powerful boiler, which is forced to work even with insignificant heat losses of the object, in the cascade solution at different times there are as many boilers as necessary to compensate for the instant heat losses of the object. The required number of boilers switched on is electronically controlled. Such operation of the boiler room precisely ensures the optimal energy-saving mode.
Practice has confirmed that a separate boiler is used on average by 30% during the heating season. This is a small load and, therefore, ineffective work. In contrast, a cascade system provides the required power gradually, connecting several "small" boilers one after the other instead of one large one. With the help of cascade control with programmed control, unpleasant problems with determining the optimal ratio of boiler power to the level of heat consumption are eliminated.
A wide range of cascade power control allows the system to operate for a long time at low temperatures heating water, which reduces the cost of thermal radiation. The thermal comfort of the user is increased. An indisputable step forward is the separation of one or more boilers from the cascade boiler house to prepare hot water... These boilers operate in summer mode, without using the bulk of equipment intended only for heating.
At the same time, boilers with the ability to provide hot water, if there is no need for it, also serve the heating system. This feature allows you to take a fresh look at the determination of the total required power of the boiler room, subject to the possible accumulation of hot water in indirect heating boilers.
Technical features of the "cascade boiler room"
A significant step forward in the history of the development of cascade boiler houses was the communication system between boilers by means of not a cascade switch, but communication devices (interfaces) that allow the exchange of information between boilers and at the same time smoothly regulate the power of all boilers in the cascade.
This allows not only to achieve optimal power parameters at every moment of operation, but also to get instant access to information about the state of the entire boiler house and its operation parameters, as well as to diagnose malfunctions of boilers and other equipment. A modern cascade boiler room is really " intelligent system»With a completely autonomous mode of operation without service personnel.
The technical solution of the cascade boiler house has an optimal price, well thought out software and wide range of applications. Due to the fact that at different times any number of boilers from the cascade boiler room included in the system can operate, and there is a need to install a main heating pump, the capacity of which exceeds the capabilities of the boiler pump, installation of a hydraulic separator is required between the cascade circuit and the heating pump.
Boiler house manufacturers offer their own sizes and configurations of hydraulic dividers and when installing boiler rooms, it is imperative to listen to the manufacturers' requirements. Otherwise, an incorrectly selected low loss header (or incorrectly installed) can disrupt the entire operation of the boiler room. Necessary elements in the operation of a cascade boiler room there are temperature probes that measure the temperature at the "supply", sensors and regulators.
The system is designed in such a way that the temperature at the outlet of the boiler room can be maintained with an accuracy of 1 ° C, which is important for such systems as forced ventilation... A cascade boiler house is so economical that in some cases it pays for the investment in just one to three months. The principle of weather-dependent regulation of the temperature of the coolant in a cascade boiler room makes it possible to save up to 30% of gas or electricity.
For this, an outside temperature sensor must be integrated into the control system. Modern devices for GSM dialers, light and sound alarms, as well as Internet communications make it easy to monitor the state of the boiler room. The simplest way to organize a cascade is to use only communication interfaces in the complete set, without using a control interface, programmer and outside temperature sensor.
Such a scheme may be required when the cascade supplies the heating medium with the same set temperature (for example, 75-80 ° C). Such a complete set of the system is acceptable when preparing the heat carrier for the pool heat exchanger. In the case of a more complex organization of heat supply, programmers are used that make it possible to maintain a given temperature in the room, display the state of the boiler room, and notify about emergency stops of boilers.
To date, cascade control panels have been developed, which combine all the necessary functions for monitoring the state of boiler room equipment, adjusting temperatures in various heating circuits and transmitting data to the Internet. Such control systems are advanced developments in the field of modern dispatching of boiler houses. In a cascade boiler room, different manufacturers combine a different number of boilers.
Therefore, the maximum capacity of the boiler rooms must be checked with the representatives of the manufacturer. But in some cases, two or more cascades can be located in one boiler room.
Accommodation conditions
The advantage of a cascade of wall-mounted boilers is that it can be placed in any permitted place (attached, built-in, detached, roof boiler room, etc.). It is very convenient to install the cascade in a roof boiler room. Low weight of the main equipment, small amount of coolant, the possibility of forced smoke extraction from each boiler at a low cost chimney prefabricated - these are the advantages of a cascade of wall-mounted boilers in relation to one or two stationary boilers installed on the roof.
There were cases when it was necessary to add a cascade of wall-mounted boilers to a boiler-house of two stationary ones due to exceeding the maximum weight and the need to ensure a given heat load. The issue of repair and replacement of equipment during operation is also important. Definitely replace the stationary multi-ton boiler installed on the roof multi-storey building, much more difficult than repairing or replacing a wall-mounted boiler, the maximum weight of which is no more than 90-100 kg.
Boilers in the boiler room can be installed "in line" or "back to back". The second method reduces the linear dimensions of the boiler room if a large number of boilers are installed.
Potential customers of cascade boiler houses
Boiler houses of this type are applicable in all areas. National economy... But they find maximum application in autonomous heating systems of one or a group of objects located at a short distance from each other. The task is not to build a heating main, which, of course, has heat loss and needs periodic maintenance and replacement of linear elements.
Cascade boiler rooms are undeniably beneficial for hotels, restaurants, private houses, auto centers, large and small store buildings. In a word, these are boiler houses for those who know how to count money and for whom the slogans about energy saving and energy efficiency are not an empty phrase. The payback period for such a system is on average two to three years, and the service life is 15-20 years.
