A heat accumulator, also known as a thermal accumulator, or a buffer tank, is gaining more and more popularity every year as one of the important elements of the heating system of a private house.
Moreover, in some European countries, the use of solid fuel heating boilers is generally prohibited, and the list of such countries is constantly updated. Yes, and in our country, the pace of sales of heat accumulators for heating boilers shows a steady increase from year to year.
Some domestic manufacturers have launched the production of thermal batteries designed specifically for Russian conditions and climatic features of our country. Let's try to figure out what the purpose of this type of equipment is, what are its features, and most importantly, what the installation of a heat accumulator will give to a particular owner of a private house, and how to choose exactly what is needed.
Heat accumulator and its use with heat sources of various types
The principle of operation of a heat accumulator is very simple: it the main task- accumulate thermal energy when there is an excess of it in the heating system, and to give this heat during its deficit, i.e. when the heat source is not working. From this follows the main conclusion - the most efficient use of heat accumulators with heat sources, which have a pronounced periodic nature of work.
These include the majority, very common both in Russia and abroad. And also rapidly gaining popularity, especially in the south,. It is clear that solid fuel boilers they heat water only during the fire, and solar collectors are useless at night.
But that's not all, even electric heating boilers in combination with heat storage can be more efficient. If the difference between daytime and nighttime electricity tariffs is significant, for example, the nighttime tariff is more than 2 times less than the daytime one, you can make the heating system in the house in such a way that it works only at night, and heat the house during the day due to the heat accumulated in the heat accumulator . By the way, taking into account the explosive growth of electricity tariffs, the economic feasibility of such a decision becomes relevant.
Another factor determining the efficiency of using heat accumulators is that a heat accumulator can become a link that combines several heat sources at once. In other words, when needed - for example, when the cost solar collectors will decrease even more, and the efficiency will increase - you will be able to rebuild the heating system in your house without significant changes in such a way as to heat the premises to the maximum due to cheap solar energy, but at the same time, when there is no sun, use a solid fuel boiler.
In this case, it becomes possible to fully accumulate all the excess heat, and then give it away as needed. In fact, the heat accumulator allows the use of various sources of thermal energy at the current minimum cost and at the same time ensures the stability of the system by switching between them. Of course, not every heat accumulator has such an opportunity - you should select the desired model in advance.
Heat accumulator in a system with a solid fuel boiler
Currently, heat accumulators are most often used in heating systems with solid fuel boilers. Feature solid fuel boilers - optimal mode their functioning is associated with the complete combustion of fuel, i.e. achieved when operating at maximum power. Otherwise, as a result of incomplete combustion of the fuel, toxic gases are formed, the heat exchange surfaces inside the boiler become clogged, soot appears in the chimney, which leads to deterioration in performance and even failure of the boiler, which is unsafe for the house and its inhabitants.
So, it is best when the boiler is working "at full". This mode is quite justified in the cold, but most the heating system of the house simply does not need a year of the amount of heat received in excess - it will be too hot. If you do not have a heat accumulator, the only way out is to "heat the street", i.e. open vents. This is both expensive and inefficient.
Therefore, a buffer tank is built into the heating system - it takes away excess thermal energy, which otherwise would simply be wasted aimlessly, in order to subsequently use them for their intended purpose, without spending fuel on this!
In short, a heating system with a solid fuel boiler and a heat accumulator works like this. During operation, the solid fuel boiler not only supplies the heated coolant to the heating system of the house, but also heats it up in the heat accumulator tank. After the boiler stops working, the house, accordingly, begins to cool. At this moment, the air temperature or the heat carrier temperature sensor in the heating system sends a signal to turn on the circulation pump, which ensures the supply of the heat carrier accumulated in the heat accumulator tank to the house heating system.
When the temperature of the air (heat carrier) rises to the set value, the sensor turns off the pump and the heat supply stops. At the same time, the temperature of the coolant in the tank decreases slightly, because part of the energy was transferred to the heating system. It should be noted that due to the good thermal insulation of the heat accumulator, the coolant, being inside the tank, cools down very slowly by itself. Cycles of turning on and off the pump continue until the temperature of the coolant in the heat accumulator remains higher than in the heating system. And the house will not cool down.
Experts estimate the economic effect of installing a heat accumulator in different ways. This effect depends on many factors, some of which will be discussed below. On average, it ranges from 20%, i.e. every 5th ruble is saved. Note that the heat accumulator is especially effective in the off-season, with its frequent temperature fluctuations.
And here comes another useful property heat accumulator - in addition to improving the safety of your home and saving you money, it also gives you comfort. Firstly, with the advent of a buffer tank in your house, you will have to load fuel into the boiler much less often. If you have calculated and installed everything correctly, if in your house good thermal insulation, using a heat accumulator, you can heat your solid fuel boiler not several times a day, but up to 1 time in 2 days.
Secondly, the heat accumulator is able to smooth out the "temperature jumps" associated with the cooling of the coolant in the heating system, because. this system becomes more stable and inertial. Thirdly, it helps to simplify the maintenance of a solid fuel boiler and even increase its service life. Fourth, with the help of a heat accumulator, you can additionally provide your home hot water, But this opportunity not available on all models.
How to choose the right heat accumulator
First you have to calculate the volume of the heat accumulator. This is important because depend on volume dimensions buffer capacity. It should be remembered that you still need to find the “right” place in the house in order to first bring in a heat accumulator of considerable width and height through the doorways, and then also install it next to the solid fuel boiler, as is most often the case in practice. Of course accurate calculations can only be done by a specialist, because this requires taking into account many specific factors, but in any case, you need to understand what kind of buffer capacity you are buying.
The volume of the heat accumulator directly depends on the power of the solid fuel heating boiler. There are several methods preliminary calculation based on determining the ability of a solid fuel boiler to heat the required volume of working fluid to a temperature of at least 40 ° C during the combustion of one full load fuel, i.e. in about 2-3 hours. It is believed that in this way the maximum efficiency of the boiler is achieved with maximum fuel economy.
But, as a rule, for a start, you can use the following calculation method: 1 kW of power of a solid fuel boiler must correspond to at least 25 liters, but not more than 50 liters of the volume of the heat accumulator connected to it.
Thus, with a heating boiler power of 15 kW, the capacity of the heat accumulator must be at least: 15 * 25 \u003d 375 liters. And no more than 15 * 50 = 750 liters. It is better to choose with a margin, i.e. about 400-500 liters.
In general, manufacturers of heat accumulators offer products of various volumes - from 40 to 10,000 liters. Attention! Heat accumulators with a capacity of more than 500 liters may not fit through the doorway of your house.
What type of heat storage is right for you
The type depends on your needs, ie. how exactly you want to use it. There are 4 conditional type thermal accumulators:
- A simple body accumulator, for connection to a single heat source;
- Buffer tank for the simultaneous connection of several heat sources, such as a solid fuel heating boiler and a solar collector. It differs from the previous type by the presence of a lower coil;
- A heat accumulator with a DHW coil is designed for both heating and production hot water in flow mode;
- A heat accumulator with an internal tank for hot water supply (tank-in-tank design) is used both for heat storage in the heating system and for the preparation and accumulation of hot water used in everyday life.
Alexander Fedotov, Head of Sales Department
“The choice of a heat accumulator depends on the goals that the heating system is designed to solve. This could be heating the building or providing heating and hot water. In the first case, a conventional insulated tank can be used, in the second case we are talking about a device with various built-in heat exchangers.
When choosing a heat accumulator, it is necessary to take into account the type of the main heat source and their quantity in the heat supply system. Important factors are also the power of the heat appliance and the hourly heat consumption».
In addition, the heat accumulator can be additionally equipped with one or more ami for autonomous water heating, when necessary.
The price of a heat accumulator depends on its volume, type, as well as on additional options and, of course, on the manufacturer's brand.
Making a heat accumulator with your own hands
The Internet is replete with various kinds of recommendations for craftsmen on how to make a heat accumulator on their own, assuring that there is nothing difficult in this. On the one hand, the abundance of these recommendations once again emphasizes the importance of heat accumulators in the heating system - useless things are not discussed. On the other hand, it makes a sane person think: when it is necessary to make a choice between buying a heat accumulator from a certified manufacturer and paying a little more, or making it “in the garage” but saving your money, you need to think first of all about the consequences.
What is a heat accumulator ✮Large selection of heat accumulators on the website portal
Because even the greatest folk craftsman, when constructing a heat accumulator from an iron barrel, as is often recommended on various sites, must understand what such imaginary savings will lead to. Firstly, the temperature of the coolant inside the heat accumulator can be close to 100°C, and secondly, there is an increased pressure inside the system. No one can predict how the handicraft buffer tank will behave during operation. Whether it is worth putting your home at risk is an open question. Everyone makes a choice.
A heat accumulator is a unit for collecting and increasing heat for the purpose of its further use. The device is used in private houses, apartments, enterprises, as well as for engine preheating. The heat accumulator for the heating system allows you to reduce energy costs for space heating and hot water supply. The units are installed in the piping of a solid fuel boiler or connected to a solar system.
Purpose of the unit
The operation of a solid fuel boiler in the heating system is a certain cyclicity. First, fuel is placed in it, ignited, and then the boiler gradually reaches maximum power and transfers thermal energy through the coolant to the heating system.
The laying of firewood gradually burns out, heat transfer decreases, and the coolant cools down. During the period of peak power, part of the thermal energy remains unclaimed, and during the burnout of the fuel, on the contrary, it will not be enough. To repeat the cycle, you must again bookmark solid fuel.
Partially, this problem can be solved by a long-burning pyrolysis boiler, but during its operation, the peaks in the production and consumption of thermal energy often do not coincide. To resolve this situation, an energy storage device is installed for the heating system, which is known as a buffer tank or heat storage.
Piping of a solid fuel boiler with a heat accumulator
The operation of this unit is based on the high heat capacity of water. If during the period of maximum power of the boiler a certain amount of water is heated, then later its energy potential can be used for heating needs.
For example, water, when cooled by 1 ° C, can heat 1 m³ of air by 4 ° C. The simplest heat accumulator for heating boilers is a vertical container with four pipes cut into different directions. There are heat accumulators with a variety of storage materials:
On one side of the body, two pipes are connected to the boiler pipelines, and on the other - to the heating system. After starting the heater, the circulation pump starts pumping the coolant through the buffer tank.
Cold coolant enters the lower part of the storage tank, and hot coolant enters the upper part. Due to the significant difference in density, the water will not mix, and the hot coolant will gradually fill the entire container.
Usually, the volume of a thermal accumulator for heating is calculated in such a way that one bookmark of fuel is enough to completely fill the tank with hot water. That is, all the energy of the boiler, excluding losses, is converted into heat, which will be accumulated in the storage tank.
Thermal insulation allows you to keep the high temperature of the water for a long time. When the boiler stops working, the heating system continues to function. Thanks to the pump, hot water from the battery enters the pipelines and home heating appliances.
In place of the hot coolant, cooled water again enters the buffer tank through the lower branch pipe from the return line of the pipeline. Using electric boiler The heating circuit with a heat storage can be used at night when the discounted rate is in effect.
Schemes of boiler rooms with a heat accumulator
All storage tanks are vertical cylindrical tanks. They differ from each other only in the elements located inside the structure. There are several types of thermal accumulators:
All such designs can be produced in various variations depending on the complexity of the heating scheme, the number and types of heaters and water circuits used. Complex devices are easy to identify by the numerous nozzles coming out of the tank.
Heat accumulator or Buffer tank. And why is it needed. Storage tank or buffer capacity principle
Heat accumulator for heating boilers
We continue our series of articles with a topic that will be of interest to those who heat their homes with solid fuel boilers. We will talk about the heat accumulator for heating boilers (TA) on solid fuels. This is a really necessary device that allows you to balance the operation of the circuit, smooth out the temperature drops of the coolant, while also saving money. We note right away that a heat accumulator for electric heating boilers is used only if the house has an electric meter with separate calculation of night and day energy. Otherwise, installing a heat accumulator for gas heating boilers does not make any sense.
How does a heating system with a heat accumulator work?
A heat accumulator for heating boilers is a part of the heating system designed to increase the time between loading solid fuel into the boiler. It is a reservoir in which there is no air access. It is insulated and has a fairly large volume. There is always water in the heat accumulator for heating, it also circulates throughout the circuit. Of course, an antifreeze liquid can also be used as a coolant, but still, due to its high cost, it is not used in circuits with TA.
In addition, there is no point in filling the heating system with a heat accumulator with antifreeze, since such tanks are placed in residential premises. And the essence of their application is to ensure that the temperature in the circuit is always stable, and, accordingly, the water in the system is warm. The use of a large heat accumulator for heating in country houses temporary residence is impractical, and a small reservoir is of little use. This is due to the principle of operation of the heat accumulator for the heating system.
- The TA is located between the boiler and the heating system. When the boiler heats up the coolant, it enters the TA;
- then the water flows through the pipes to the radiators;
- The return line returns to the TA, and then immediately to the boiler.
Although the heat accumulator for the heating system is a single vessel, due to its large size, the flow direction at the top and bottom is different.
In order for TA to perform its primary function of heat storage, these streams must be mixed. The difficulty lies in the fact that heat always rises, and the cold seeks to descend. It is necessary to create conditions so that part of the heat sinks to the bottom of the heat accumulator in the heating system and heats the return coolant. If the temperature has evened out in the entire tank, then it is considered fully charged.
After the boiler fired everything that was loaded into it, it stops working and TA comes into play. The circulation continues and it gradually releases its heat through the radiators into the room. All this happens until the next portion of fuel enters the boiler again.
If the heat storage for heating is small, then its reserve will last for a very short time, while the heating time of the batteries increases, since the volume of the coolant in the circuit has become larger. Cons of using for temporary residences:
- the warm-up time increases;
- a larger volume of the circuit, which makes filling it with antifreeze more expensive;
- higher installation costs.
As you understand, filling the system and draining water every time you arrive at your dacha is at least troublesome. Considering that the tank alone will be 300 liters. For the sake of several days a week, it is pointless to take such measures.
Additional circuits are built into the tank - these are metal spiral pipes. The liquid in the spiral does not have direct contact with the coolant in the heat accumulator for heating the house. These can be contours:
- low-temperature heating (warm floor).
Thus, even the most primitive single-circuit boiler or even a stove can become a universal heater. It will provide the entire house with the necessary heat and hot water at the same time. Accordingly, the performance of the heater will be fully utilized.
In serial models manufactured under production conditions, additional heating sources are built in. These are also spirals, only they are called electric heating elements. There are often several of them and they can work from different sources:
- circuit;
- solar panels.
This heating is additional options and is not mandatory, consider this if you decide to make a heat accumulator for heating with your own hands.
Heat accumulator piping schemes
We dare to assume that if you are interested in this article, then most likely you decided to make a heat accumulator for heating and tie it yourself. You can come up with a lot of connection schemes, the main thing is that everything works. If you correctly understand the processes occurring in the circuit, then you can quite experiment. How you connect the HA to the boiler will affect the operation of the entire system. Let's first take a look at the most a simple circuit heating with a heat accumulator.
A simple TA strapping scheme
In the figure you see the direction of movement of the coolant. Please note that upward movement is prohibited. To prevent this from happening, the pump between the TA and the boiler must pump a larger amount of coolant than the one that stands up to the tank. Only in this case will a sufficient retracting force be formed, which will take part of the heat from the supply. The disadvantage of such a connection scheme is long time circuit heating. To reduce it, you need to create a boiler heating ring. You can see it in the following diagram.
TA piping scheme with a boiler heating circuit
The essence of the heating circuit is that the thermostat does not mix water from the TA until the boiler warms it up to the set level. When the boiler is warmed up, part of the supply goes to the TA, and the part is mixed with the coolant from the reservoir and enters the boiler. Thus, the heater always works with an already heated liquid, which increases its efficiency and the heating time of the circuit. That is, the batteries will get warm faster.
This method of installing a heat accumulator in a heating system allows you to use the circuit offline when the pump is not running. Please note that the diagram shows only the nodes for connecting the TA to the boiler. The circulation of the coolant to the radiators occurs in a different way, which also passes through the TA. The presence of two bypasses allows you to play it safe twice:
- the check valve is activated if the pump is stopped and the ball valve on the lower bypass is closed;
- in the event of a pump stop and breakdown check valve circulation is carried out through the lower bypass.
In principle, some simplifications can be made in such a construction. Given the fact that the check valve has a high flow resistance, it can be excluded from the circuit.
TA piping scheme without check valve for gravity system
In this case, when the light disappears, you will need to manually open the ball valve. It should be said that with such a wiring, the TA should be above the level of the radiators. If you do not plan that the system will work by gravity, then the piping of the heating system with a heat accumulator can be performed according to the scheme shown below.
TA piping scheme for circuit with forced circulation
In TA, the correct movement of water is created, which allows ball after ball, starting from the top, to warm it up. Perhaps the question arises, what to do if there is no light? We talked about this in an article about . It will be more economical and more convenient. After all, gravity circuits are made of large-section pipes, and besides, not always convenient slopes must be observed. If you calculate the price of pipes and fittings, weigh all the inconveniences of installation and compare it all with the price of a UPS, then the idea of \u200b\u200binstallation alternative source nutrition will become very attractive.
Calculation of the volume of the heat storage
The volume of the heat accumulator for heating
As we have already mentioned, it is not advisable to use a small volume TA, while too large tanks are also not always appropriate. So the question arose of how to calculate the required volume of TA. I really want to give a specific answer, but, unfortunately, it cannot be. Although there is still an approximate calculation of a heat accumulator for heating. Let's say you don't know what heat loss your house is and you can't find out, for example, if it hasn't been built yet. By the way, to reduce heat loss, you need . You can choose a tank based on two values:
- the area of the heated room;
- boiler power.
Methods for calculating the volume of TA: room area x 4 or boiler power x 25.
It is these two characteristics that are decisive. Different sources offer their own calculation method, but in fact these two methods are closely related. Suppose we decide to calculate the volume of a heat accumulator for heating, starting from the area of \u200b\u200bthe room. To do this, you need to multiply the quadrature of the heated room by four. For example, if we have little house 100 square meters, you will need a tank of 400 liters. This volume will reduce the loading of the boiler up to two times a day.
Undoubtedly, and so it is pyrolysis boilers, in which fuel is laid twice a day, only in this case the principle of operation is slightly different:
- fuel ignites;
- the air supply is reduced;
- the smoldering process begins.
In this case, when the fuel flares up, the temperature in the circuit begins to rise rapidly, and then smoldering keeps the water warm. During this very smoldering, a lot of energy escapes into the pipe. In addition, if a solid fuel boiler works in tandem with a leaky heating system, then at peak temperature expansion tank sometimes boils. In the truest sense of the word, water begins to boil in it. If the pipes are made of polymers, then this is simply fatal for them.
In one of the articles about TA, it takes some of the heat and the tank can boil only after the tank is fully charged. That is, the possibility of boiling, with the right amount of TA, tends to zero.
Now let's try to calculate the volume of TA, based on the number of kilowatts in the heater. By the way, this indicator is calculated on the basis of the quadrature of the room. 1 kW is taken for 10 m. It turns out that in a house of 100 square meters there should be a boiler of at least 10 kilowatts. Since the calculation is always done with a margin, we can assume that in our case there will be a 15 kilowatt unit.
If you do not take into account the amount of coolant in the radiators and pipes, then one kilowatt of the boiler can heat approximately 25 liters of water in the TA. Therefore, the calculation will be appropriate: you need to multiply the boiler power by 25. As a result, we will get 375 liters. If we compare with the previous calculation, the results are very close. Only this, taking into account that the boiler power will be calculated with a gap of at least 50%.
Remember, the more TA, the better. But in this case, as in any other, one must do without fanaticism. If you put a TA for two thousand liters, then the heater simply cannot cope with such a volume. Be objective.
A heat accumulator is a device capable of accumulating thermal energy from a heat source when it is produced in excess, and then using its reserve if necessary.
The heat source can be a heating boiler, stove, solar collector, etc.
In fact, any massive body that has a temperature greater than absolute zero has a store of thermal energy. The amount of accumulated heat depends on the degree of heating and body weight.
For example, any building made of brick, stone or concrete blocks (materials capable of accumulating heat) is a heat accumulator, the continuous operation of which few people pay attention to. But it is precisely thanks to the heat reserve accumulated by the walls of the house that it is cool in a hot day and warm at night when the outside temperature drops, the system works natural ventilation, and there are no sharp jumps in temperature during a short-term shutdown of heating or during ventilation.
Another example of a heat accumulator is a Russian stove or any other stone or brick heating stove. When burning firewood, the stove array accumulates thermal energy, and then, cooling down, gives it to the surrounding space.
The greater the weight of the oven, the more heat it has and the longer it can maintain comfortable temperature in room. It is for this reason that the traditional Russian stove is made massive, weighing up to one and a half tons or more, and it is heated periodically: once a day.
Traditionally, stones or baked bricks were used to accumulate heat, but their use is justified only for stove heating, the use of which in simple modern houses not always convenient. For heating modern dwelling more often they use not furnaces, but heating boilers.
Which boilers need a heat accumulator?
A heat accumulator is necessary only for boilers that operate periodically: coal or wood. Boilers operating uninterruptedly (gas or electric), equipped with continuous fuel supply systems, long-burning boilers do not need heat accumulation.
Solid fuel traditional boilers need periodic laying of firewood, the time of complete combustion of fuel in them is no more than 3 hours. At the end of the combustion process, the coolant in the heating system will not only cool down to the temperature of the air in the room, but also in the places of the boundary laying of the pipeline (along the floor, in the basement, in the attic) can freeze, forming ice plugs in the heating system blocking the circulation of water.
Under these circumstances, it is no longer comfortable conditions in the house, but about the integrity and safety of the heating system. The main task of heat accumulation in systems with a solid fuel heating boiler is to create a reserve of thermal energy, the use of which during the idle period of the boiler will help to avoid a sharp drop in temperature in the room and avoid freezing of the coolant.
Heat accumulator device
A heat accumulator for a heating boiler should be convenient not only for heat accumulation, but also for its further use. The only substance suitable for solving the problem is the coolant. It can be water or antifreeze placed in an impressive container included in the heating system.
To preserve heat, the container is additionally insulated: sheathed with mineral wool, foil, heat-insulating panels, installed on an insulated base.
The volume of the heat accumulator is chosen according to the principle, the more the better, but usually we are talking about a capacity of 2-5 m3. Another important addition: the tank must be airtight, with two holes: for connecting the pipeline.
The heat accumulator is connected to the heating system in parallel with the boiler according to the principle of a heating device with connection to both the supply and the return. Must be installed on delivery shut-off valves, which allows you to change the direction of movement of the coolant, letting it either only to the heating devices, or only to the heat accumulator, or at the same time both there and there. As a rule, this is a three-way valve.
How does a heat accumulator work in a heating system?
With intensive burning of firewood in a solid fuel boiler, maximum heat generation occurs, which allows heating not only the radiators in the house, but also the water supply in the battery. After the firewood burns out, the heat from the boiler stops flowing, but the circulation of the coolant in the system continues: cold water rolls down, and a hotter coolant from the battery enters the system.
Return water, returning to the heating boiler, also passes through the accumulator. If the return temperature is higher than the temperature of the water in the tank, then the liquid inside is additionally heated by the return. If the return is cold, then, on the contrary, it is heated before entering the boiler, which reduces the temperature difference between the hot boiler and cold return water.
The larger the battery, the longer the system can work without "recharging".
Practical use
A heat accumulator in a heating system with a solid fuel boiler can be safely called a real find for its owners. It is this simple device that allows you to leave the house for several hours even in severe frosts, without fear for the safety of the heating system, sleep peacefully at night, without jumping up to the boiler to lay a new portion of firewood and not be afraid of the destruction of the boiler when too cold coolant enters it.
A three-way valve is used to control the operation of the heating system with a heat accumulator.
With it, you can open the movement of the hot coolant only to the heating devices, which is usually done if you want to quickly warm up the room. If the house is already hot, and the boiler continues to work, you can turn off the water supply to the radiators and send it only to the heat accumulator.
For simultaneous heating of heating devices and a heat accumulator, an intermediate position of the tap is selected.
Heat accumulator and circulation pump
As a rule, solid fuel boilers are used in gravity heating systems. In this case, the heat accumulator works due to natural convection: a cold coolant enters it through the lower pipe, and a more heated liquid flows upwards to the heating devices.
In systems with a circulation pump, the heat accumulator also works, but here the speed of the coolant is set by the pump, which undoubtedly has a positive effect on the operation of the entire heating system.
On the advantages and disadvantages
The installation of a heat accumulator makes the operation of the heating system stable, excluding sudden temperature changes not only in the house, but also in the flow of coolant into the boiler.
The only drawback of a heat storage tank is its size: a small capacity does not allow heat to be stored and used, and it is not always possible to find enough space for a large volume tank. Yes, and to install the tank, you will have to strengthen the foundation or place it in the basement.
Heat accumulator for heating boilers
Why do you need a heat accumulator for heating boilers? How is it set up and how does it work? Practical application of the heat accumulator
Heat accumulator for boiler
When designing a heating system, the main goals are comfort and reliability. The house should be warm and comfortable, and for this, hot coolant must always flow into the radiators without delays and temperature fluctuations.
With a solid fuel boiler, this is difficult to implement, because it is not always possible to fill a new portion of firewood or coal on time, and the combustion process itself is uneven. A heat accumulator for heating boilers will help to correct the situation.
With a simple design and operation principle, it is able to get rid of a number of inconveniences and shortcomings. classical scheme heating.
Why do you need
The heat accumulator is a well-insulated large-capacity tank filled with a coolant, water. Due to the high heat capacity of water, when the entire volume is heated, a significant supply of thermal power is accumulated in the tank, which can be used for its intended purpose at a time when the boiler cannot cope or is completely inactive.
The heat accumulator actually increases the volume of the coolant in the heating circuit, the heat capacity and, accordingly, the inertia of the entire system. It will take more energy and time to heat the entire volume with a limited heating power, but it will also take a very long time to cool the battery. If necessary, hot water from the accumulator can be supplied to the heating circuit and maintain a comfortable temperature in the house.
To appreciate the benefits of a heat storage, it is easiest to consider a few situations to begin with:
- A solid fuel boiler only periodically heats the water. At the moment of ignition, the power is minimal, during active combustion, the power increases to a maximum, after the bookmark burns out, it decreases again and so the cycle repeats. As a result, the temperature of the water in the circuit constantly fluctuates in a fairly large range,
- To obtain hot water, it is necessary to install an additional heat exchanger or an external boiler with indirect heating, which significantly affects the operation of the heating circuit,
- It is extremely difficult to connect additional heat sources to a heating system built around a solid fuel boiler. A complex interchange will be required, preferably with automatic control,
- A solid fuel boiler, even for a long time burning, constantly requires the attention of the user. It is worth skipping the time for laying a new portion of fuel, as the coolant in the heating circuit is already starting to cool down, like the whole house,
- Often the maximum power of the boiler is excessive, especially in spring and summer, when maximum output is not required.
The solution for all of the above situations is a heat accumulator, moreover, uncompromising and the most affordable in terms of implementation and cost. It acts as a decoupling point between the solid fuel boiler and the heating circuit(s) and an excellent base platform for enabling additional functions.
By design, the heat accumulator can be:
- "empty" - a simple insulated container with a direct connection,
- with coil or pipe register as heat exchanger,
- with built-in boiler tank.
With a full body kit, the heat accumulator is capable of:
- Accumulate and store a significant amount of thermal energy, primarily excess, with its subsequent return to the heating circuit. Even if you miss one or two refills of wood and the boiler stops, the temperature in the house will drop by only a couple of degrees. For electric boilers, it is possible to set a schedule according to which electricity will be consumed only at night at a reduced rate, while during the day the heat will come from the heat accumulator,
- If there is a lower heat exchanger, connect additional heat sources, a solar collector, a spare boiler running on gas or diesel fuel, a geothermal heat pump,
- With built-in heating elements, be used as a backup source of heat in case the solid fuel boiler is not working or is turned off for maintenance and repair,
- In the presence of an upper heat exchanger - for connecting a DHW circuit or an indirect heating boiler. Some models of heat accumulators are equipped with a ready-made boiler located inside the main tank instead of a heat exchanger,
- Implement additional protection in systems with forced circulation in case of a power outage, preventing overheating of the water in the boiler. Considering the tank as a hydraulic decoupling unit, it can be connected in a mixed circuit with a boiler, above it and pipes larger diameter to maintain natural circulation. At the same time, distribution to the radiators will be carried out by the pump forcibly.
The power accumulated by a heat accumulator (TA) is calculated based on the volume of the container, more precisely, the mass of the liquid in it, the specific heat of the liquid used to fill it, and the temperature difference, the maximum to which the liquid can be heated, and the minimum target, at which it can still be carried out. heat intake from the heat accumulator to the heating circuit.
- Q \u003d m * C * (T2-T1),
- m - mass, kg,
- C - specific heat W / kg * K,
- (T2-T1) - temperature delta, final and initial.
If the water in the boiler and, accordingly, in the TA is heated to 90ºС, and the lower threshold is taken equal to 50ºС, then the delta is equal to 40ºС. If we take water as filling TA, then one ton of water, when cooled by 40ºС, releases approximately 46 kWh of heat.
Heat accumulator for boiler
In the article you can read what a heat accumulator for a boiler is and how to choose it. Heat accumulator connection diagram and manufacturers.
Heat accumulator, its device and principle of operation.
Good day everyone! If you have landed on this page of my blog, then you are interested in at least 2 questions:
- What is a heat accumulator?
- How is a heat accumulator arranged?
I will start answering these questions in order.
What is a heat accumulator?
In order to answer this question, a definition needs to be given. It sounds as follows, a heat accumulator is a container in which a large volume of hot coolant accumulates. Outside, the container is covered with thermal insulation made of mineral wool or polyethylene foam.
Why do you need a heat accumulator?
You ask: “Why do we need this overgrown thermos?” Everything is very simple here, it allows you to optimally use the heat given off by the boiler. Paired with a heat accumulator, a powerful boiler (most often solid fuel) always works. The boiler quickly and non-stop transfers heat from the burned fuel to the heat accumulator, and it, in turn, slowly and in the right mode gives this heat to the heating system. The volume of the system is much smaller than the capacity of the battery. This allows you to "stretch" the heat from the fuel over time. It turns out, in fact, a long-burning boiler. When the battery capacity is heated, the boiler constantly works on full power, and this avoids the appearance of tarry condensate in the chimney and boiler.
How is a heat accumulator arranged?
As mentioned above, TA is a container in which hot water (or other coolant) accumulates. To make it clear, look at the following figure:
The tank has several nozzles for connecting various equipment:
- Thermal energy generator - boiler, solar collector, heat pump.
- Plate heat exchanger for heating hot water.
- Various boiler equipment - safety group, expansion tank and so on.
Water container materials.
Heat accumulator connection diagram.
Now let's look at how the battery is included in the heating system:
From this diagram it can be seen that the TA is included in the heating system as a hydraulic separator (hydraulic arrow). I recommend reading a separate article dedicated to this useful device. I will say briefly that such a switching scheme excludes the mutual influence of different circulation pumps and allows you to provide the boiler with the required volume of coolant, which has a positive effect on the life of the heat exchanger.
Heat accumulator and hot water supply.
Another important issue is the device in the house of hot water. Here TA can also come to the rescue. Of course, it is impossible to use water directly from the heating system for sanitary needs. But there are at least two solutions here:
- Connection to the TA of a plate heat exchanger, in which sanitary water will be heated - is used in the most simple models TA.
- Purchase of a heat accumulator with a built-in DHW system - it can be implemented using either a separate heat exchanger (coil) or according to the “tank in tank” scheme.
You can, of course, also purchase an indirect heating boiler separately, but I believe that this can only be done if you have the necessary space in your boiler room.
A heat accumulator is another way to increase the time between fuel fillings in the boiler. In addition, TA can be used in systems with solar collectors and heat pumps. Most often, TA is used as a replacement for long-burning boilers. The alternative is certainly interesting and worthy of your attention. This concludes my story. I look forward to your questions in the comments.
Heat accumulator, its device and principle of operation
Heat accumulator, its device and principle of operation. What is a heat accumulator? Why do you need a heat accumulator? Materials of the water-containing capacity of the heat accumulator. Heat accumulator and hot water supply.
For heating suburban facilities, solid fuel boilers are used if other types of fuel are not available or unreasonably expensive. To everyone heating season the owner of the cottage has to procure the necessary supply of firewood and coal, the volume of which depends on the area of the object and the quality of its thermal insulation, as well as the severity of climatic conditions in the region of residence. Most models of solid fuel boilers can provide a comfortable temperature in the house if they are heated twice a day at a strictly defined time. If you shift the ignition time of the fuel in the combustion chamber of the unit, then it becomes cold in the living room. An exception is long-burning boilers, which can maintain the required temperature in the house for several days. The same result can be achieved from a conventional solid fuel boiler, if an additional unit is included in the heating system, capable of accumulating excess heat generated by the unit when burning a portion of fuel. Such nodes include buffer tanks or heat accumulators, which are also called drives.
Installing a heat accumulator allows you to:
- organize boiler maintenance at a convenient time of the day,
- increase the time between successive fuel loads without reducing the comfort of living in the house,
- optimize house maintenance costs by reducing purchases of solid fuels.
The use of solid fuel boilers in conjunction with buffer tanks allows you to reduce the cost of solid fuel at times, while ensuring the required level of comfort in the house. The return on the installation of a storage tank can be significantly increased if intelligent controllers and sensors are used in the operation of the heating system. When the set temperature values are reached in the premises of the house, the supply of coolant to the heating devices is stopped.
The heat released by the boiler that continues to operate is accumulated in the buffer tank, and then it is given off to the cooled coolant, which begins to circulate through the system, bypassing the burned-out boiler. The larger the volume of the buffer tank, the longer the house will be heated due to the thermal energy accumulated in it.
Advantages of using a thermal storage tank in a heating system country house connected to several heat generators
Heat accumulator for heating boilers: device, types, connection principles
Installation of a heat accumulator is necessary to increase the performance of a solid fuel boiler and reduce fuel consumption.
The internal structure and principle of operation of the heat accumulator for heating boilers is designed to ensure that the required temperature of the heat carrier is maintained for 5-10 hours after the main energy source is turned off. storage tank is placed in a harness with solid fuel and electric boilers. Can be connected to a heat pump and solar collectors.
What is buffer capacity
In fact, this is a tank with a built-in DHW coil and a heat-insulating casing. The purpose of the tank is to accumulate excess thermal energy. After turning off the main source of heating of the coolant, the tank replaces it for a certain time.A properly used principle of operation of a buffer tank in a heating system reduces heating costs and makes heating a building more comfortable. To make sure that it is expedient to connect a tank, it is necessary to consider its structure and principle of operation, as well as take into account the existing advantages and disadvantages.
Device and principle of operation
The heat storage tank is a conventional metal barrel, With external thermal insulation. A simple heat storage device, however, is highly efficient and indispensable for heating systems. The buffer tank in the section consists of several nodes:- Tank - made of sheet metal(enamelled), stainless steel. Branch pipes depart from the tank for connection to the heating system and the heat generator. The material of the tank largely determines the service life of the heat accumulator.
- Spiral heat exchanger- installed in models connected to heating systems with several types of heat carriers (heat pump, solar collectors). Made from stainless steel.
- Built-in DHW coil- some buffer tanks, in addition to maintaining the heating temperature of the coolant in the heating system, heat water for hot water supply.
In the case there is an inspection window for servicing the tank, removing scale and debris, carrying out repair work if necessary.
Purpose of heat accumulators
The basis of the operation of the buffer tank is due to the fact that the excess thermal energy is accumulated, after which it is used to heat the building and hot water. A heat accumulator in the heating system is needed to maintain a comfortable temperature in a residential building after the main source of thermal energy is turned off.The purpose of installing a storage tank varies depending on the type of heat source: 
The tasks and purposes of using heat accumulators are different. In some cases, the installation of a tank is an indispensable condition for operation, in others it is only a desired requirement that ensures comfortable and economical heating building.
Pros and cons of buffer capacity
The first and obvious drawback: the high cost of the tank. High-quality products made in the EU or in Russia will cost from 25,000 to 300,000 rubles. Another disadvantage: the large dimensions of the product. Often it is necessary to install tanks of 1000 or more liters, which take up a lot of space.Now about the benefits of connecting. There are several of them:
- Possibility of uninterrupted operation of solid fuel boilers- if a buffer tank is not installed in the heating system, the coolant begins to cool immediately after the firewood burns out. A drop in temperature is felt by a person after about 3 hours.
Cooling down will be slower when a heat accumulator is connected. The water in the heating system will remain hot for about 5-10 hours (depending on the volume of the heat accumulator). - Profitability - excess thermal energy is accumulated and used when the coolant cools down, which significantly reduces fuel costs.
- Safety - the operation of boilers with cast-iron heat exchangers is facilitated. After the tank, the water enters the boiler warm, which eliminates damage to the core from rapid cooling.
- Additional functions- in the device of some tanks there is a DHW coil. There is a simultaneous accumulation of the heated coolant and heating of hot water. The installation can satisfy the needs for hot water supply of residents of the house using single-circuit solid fuel or electric boilers not designed to provide hot water.
Which heat accumulator to choose
It is better to entrust the selection of storage capacity to specialists. You will need to choose a tank that is optimally suited for the type of heating equipment used. The selection of a heat accumulator for a solid fuel boiler and a heat pump may differ. Leading manufacturers in the operating instructions directly indicate for which type of heating system this or that buffer tank is intended. When choosing, pay attention to several specifications:
- Storage tank material- a stainless steel tank is unreasonably expensive, especially considering that the battery receives a coolant from the heating system, which is less aggressive than water in the hot water supply. Enamelled coating using glass polymers, the optimal solution.
- Additional functions- it is possible to select a tank for various water consumers, connect heating systems using water as a coolant and special compositions (heat pump, solar collectors). Special mention should be made of tanks capable of heating water simultaneously with the accumulation of thermal energy.
How to calculate buffer capacity
To select the required volume of the heat accumulator, you can go three ways. The first is related to the use of special online calculators. You will need to enter the following parameters:- heated area;
- boiler power;
- time of autonomous maintenance of temperature in the heating system after the boiler is turned off.
To get the exact value, use the second method, according to the formulas for calculating the buffer capacity. During the calculations, several values are calculated:
- accumulator accumulation time or water heating up to the temperature of 80-90°С;
- battery life;
- boiler power.
- Q = m×cp×(T2-T1)- according to the calculations, it will be possible to calculate how long it will take to accumulate sufficient thermal energy and find out possible losses. Values:
- m - coolant flow rate;
- cp - specific heat capacity;
- T2 and T1 - initial and final temperature of water heating in the tank.
- Calculations for solar collectors are carried out somewhat differently. The formula Va=Sl × (Vn/Sn) is used. In order not to go into technical details in the calculations, you can use the following table:
And lastly, the capacity of the buffer tanks is chosen so that 30-50 liters of coolant account for 1 kW of boiler energy.
For convenience in the calculations, you can use the following table:
Definition minimum quantity the heat produced in kW is done using the tables attached below.
Calculations for electric boilers, subject to the use of the night tariff:
Minimum required power to maintain a buffer tank connected to a solid fuel boiler in working condition:
Which company to buy a buffer drive
After performing the calculations and determining the desired technical characteristics, you can proceed to the selection of heat accumulators by manufacturer. Not only European products are represented on the market. There are heat accumulators for heating boilers Russian production, which are not inferior in quality to eminent foreign equipment.To facilitate the choice of buffer capacity, the following is a description of the most popular models for domestic consumers: 
From the presented list of heat accumulators, you can choose equipment suitable for housing of any size, heated by an electric or solid fuel boiler, heat pump, with and without the possibility of heating hot water.
Immediately after connecting the buffer tank, fuel costs will decrease by 15-30%. More importantly, the boiler will no longer be subjected to hydraulic shocks, and the heating of the coolant in the heating system will become more uniform. The battery tank occupies an integral place in modern systems heating.
