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. The 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 correctly 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 (with enamel coating), 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, and carrying out repairs 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 of the 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 that are 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 technical characteristics:
- 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:
The determination of the minimum amount of heat produced in kW is carried out using the tables attached below.
Calculations for electric boilers, subject to the use of the night tariff:
The minimum required power to maintain the buffer tank connected to the 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 Russian-made heating boilers, 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 storage tank occupies an integral place in modern heating systems.
In our homes, this is exactly the kind of heating - we would not put bad things on ourselves.
My team and I installed the same heating system in more than 60 houses.
Submit an application
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A heat accumulator and a nightly electricity tariff are the most profitable and cheapest system after the main gas.
All other heating options - wood pallets, wood boilers, diesel fuel - in any case are more expensive. And you need to bother with them, constantly make sure that there is firewood or gas.
Here is a diagram of my heating system.
rice. storage tank in the heating system
What we have?
From the heat accumulator through the heat head (you can adjust the temperature), the coolant is supplied to the floors. Here I also have a coil wound, which removes heat from the heat accumulator, and from it, from the coil, the coolant goes to the floors.
Accordingly, the heating of the heat accumulator occurs due to the heating elements, i.e. electricity. And plus, if there is not enough heat, I also connect a wood-burning boiler (but in 4 winters I heated it a maximum of 10 times, and then purely for the sake of maintaining its functionality, I drove the pumps, cleaned the chimney with fire, etc.)
As for the main gas, why don't I use it?
I have two pipes running along the site. But the owners set very high price tags for connections. One asks for 800 thousand rubles, the other 1.1 million rubles. Well, it's not serious at all.
I calculated and it turned out that such a connection will pay off for me in 66 years. That is, the pipes are not public, but private.
That is, if connecting to gas costs 300,000 rubles (I include here the gas project, bringing gas into the house, piping it with your heating system), then there is probably some logic here. So that it pays off for you (and then it will pay off for you for 20 years).
Now let's return to the heating system of the frame house with the help of a heat accumulator and a nightly electricity tariff.
In what cases is this relevant?
➤ First - and most importantly - good insulation of your home. Properly made project and insulation in the walls of 150-200 mm, and in the ceiling of 200-250 mm of basalt wool.
➤ The second is the availability of dedicated electricity capacity. You should have at least 15 kW. That is, if you have a category of land for permanent residence, then by default the power engineers provide you with 15 kW of power in three phases. It's enough.
➤ The third parameter is the presence of a night tariff. If you, for example, connect to the Moesk system, they will offer you a nightly rate (from 11 pm to 7 am) by default.
We will use this tariff to the maximum, when electricity is three times cheaper than during the day.
When is the best time to lay the heating system at home and do it?
This is best thought out during the design phase of your home. Because the most efficient heating system with a heat accumulator works in conjunction with underfloor heating.
I have seen when a heat accumulator is used in conjunction with radiators. But the downside is that the heat accumulator is a large capacity. It is quite difficult to heat it, you need a lot of power. And in principle, it can be heated to 80-85 ºС, and the radiator will take it all off in 3-4 hours. By evening, the house will be cold.
When using a gas boiler, we do not need to independently maintain a certain temperature in the heating circuit - this is done by automation. But everything changes when a solid fuel boiler is installed in the house. The fuel in it burns unevenly, which leads to cooling or overheating of the heating system. A heat accumulator for heating will help to compensate for these fluctuations and stabilize the temperature in the circuit. A capacious storage tank will be able to retain an excess of thermal energy, gradually giving it to the heating system.
In this review, we will look at:
- How do heat accumulators for heating systems work;
- How to calculate the required volume of the battery tank;
- How are storage tanks connected?
- The most popular models of thermal storage devices.
Let's go through these points in more detail.
The principle of operation of heat accumulators
If you install a solid fuel boiler in the house, there will be a severe need to regularly add new portions of firewood. It's all about the limited volume of the combustion chamber - it cannot accommodate an unlimited number of logs. Yes, and systems for their automatic supply have not yet been invented, if we do not take into account pellet boilers with automation. In other words, you will have to monitor the operation of the heating system yourself.
These boilers develop maximum power at the moment when firewood blazes merrily in them. At this point, they give a lot of extra energy, so users dose the firewood carefully, putting them in one log at a time. Otherwise, the house will be too hot. There is nothing good in this, because because of this, the number of approaches increases, which is already high. The problem is solved with the help of a heat accumulator.
A thermal accumulator for heating is a storage tank in which a hot coolant accumulates. Moreover, energy is given to the heating circuit in a strictly dosed manner, which ensures temperature stability. Due to this, households get rid of temperature fluctuations and frequent approaches for laying firewood. Accumulation tanks are able to accumulate excess heat energy and smoothly release it to the heating circuits.
Let's try to explain the principle of working on the fingers:
The simplicity of the design of the thermal accumulator not only increases the reliability of the unit, but also simplifies repairs and scheduled maintenance.
- The heating boiler installed in the heating system with a heat accumulator is loaded with firewood and produces a large amount of thermal energy;
- The received energy is sent to the thermal battery and accumulates there;
- At the same time, with the help of a heat exchanger, heat is taken in for the heating system.
A buffer tank for heating (aka a heat accumulator) operates in two modes - accumulation and return. In this case, the power of the boiler may exceed the required heat output for heating the home. While firewood is burning in the firebox, heat will accumulate in the thermal accumulator. After the logs go out, energy will be taken from the battery for a long time.
The heat accumulators of Lyzhebok for hotbeds and greenhouses are arranged in approximately the same way - during the day they accumulate heat from the sun, and at night they give it away, warming the plants and preventing them from freezing. They just look a little different.
Heat accumulators for heating systems are also necessary if solar panels or heat pumps are used as a heat source. The same batteries cannot provide heat around the clock, since at night their efficiency drops to zero. During daylight hours, they will not only heat the house, but also accumulate thermal energy in the storage tank.
Heat accumulators can be useful when using electric boilers . Such a scheme justifies itself on a two-tariff payment system. In this case, the system is configured so that heat is accumulated at night, and heat is released during the day. Thanks to this, consumers have the opportunity to save money on electricity consumption.
Varieties of heat accumulators
The heat accumulator for the heating system is a capacious tank equipped with solid thermal insulation - it is she who is responsible for minimizing heat loss. With the help of one pair of pipes, the battery is connected to the boiler, and with the help of another pair - to the heating system. Also, additional pipes can be provided here for connecting a DHW circuit or additional sources of thermal energy. Let's look at the main types of heat accumulators for heating systems:
With the presence of a circulation pump, it becomes possible to use several buffer tanks at once, which allows you to evenly heat several rooms at once.
- Buffer tank - is a simple tank, devoid of internal heat exchangers. The design provides for the use of the same coolant in the boiler and batteries, at the same allowable pressure. If it is planned to pass one coolant through the boiler, and another through the batteries, an external heat exchanger should be connected to the heat accumulator;
- Heat accumulators for individual heating with lower, upper or several heat exchangers at once - such heat accumulators allow you to organize two independent circuits. The first circuit is a tank connected to the boiler, and the second is a heating circuit with batteries or convectors. The heat carriers do not mix here, in both circuits there may be different pressures. Heating is carried out using a heat exchanger;
- With a flow heat exchanger of the DHW circuit or with a tank - for organizing hot water supply. In the first case, water can be consumed all day and evenly. The second scheme provides for the accumulation of water in order to quickly return it at a certain time (for example, in the evening, when everyone takes a shower before going to bed) - indirect boilers that accumulate water are arranged in a similar way.
The design of heat accumulators for heating can be very different, the choice of the appropriate option depends on the complexity of the heating system, its characteristics and the number of hot coolant sources.
Some heat accumulators are equipped with heating elements with thermostats, which makes it possible to provide consumers with heat at night, when the coolant has already cooled down, and there is no one to throw firewood into the furnace. They are also useful when using heat pumps and solar panels.
Calculation of the volume of the heat accumulator
We have come close to the most difficult issue - to calculate the required volume of the heat accumulator. To do this, we will use the following formula - m=W/(K*C*Δt). The letter W denotes the amount of excess heat, K is the efficiency of the boiler (indicated as a decimal fraction), C is the heat capacity of water (heat carrier), and Δt is the temperature difference, determined by subtracting the temperature of the heat carrier on the return pipe from the temperature on the supply pipe. For example, it can be 80 degrees at the outlet and 45 degrees at the return - in total we get Δt = 35.
First, let's calculate the amount of excess heat. Suppose that for a house of 100 square meters. m. we need 10 kW of heat per hour. The burning time on one bookmark of firewood is 3 hours, and the boiler power is 25 kW. Consequently, in 3 hours the boiler will generate 75 kW of heat, of which only 30 kW must be sent for heating. In total, we have 45 kW of excess heat left - this is enough for another 4.5 hours of heating. In order not to lose this heat and not to reduce the amount of loaded firewood (otherwise we will simply overheat the system), you should use a heat accumulator.
As for the heat capacity of water, it is 1.164 W * h / kg * ° C - if you do not understand physics, just do not go into details. And remember that if you use a different coolant, then its heat capacity will be different.
Having carried out the necessary calculations, using our advice, you can easily choose a model that most accurately satisfies all your requests.
In total, we have all four values \u200b\u200b- this is 45,000 W of heat, the efficiency of the boiler (suppose 85%, which will be 0.85 in fractional terms), the heat capacity of water is 1.164 and the temperature difference is 35 degrees. We carry out calculations - m \u003d 45000 / (0.85 * 1.164 * 35). With these figures, the volume is 1299.4 liters. We round up and get the capacity of the heat accumulator for our heating system equal to 1300 liters.
If you can’t do the calculations yourself, use special calculators, auxiliary tables or the help of specialists.
Wiring diagrams
The simplest scheme for connecting a heat accumulator to a solid fuel boiler involves the use of the same coolant at equal pressure in the boiler and the heating system. For these purposes, the simplest storage tank without heat exchangers is suitable. Two pumps are installed on the return pipes - by adjusting their performance, we will ensure temperature control in the heating system. There is also a similar scheme using a three-way valve - it allows you to control the temperature by mixing the hot coolant and the cooled coolant from the return pipe.
Heat accumulators with a built-in heat exchanger are designed to work in heating systems with high heat carrier pressure. To do this, heat exchangers are located inside them, connected through a circulation pump to the boilers - this is how a supply circuit is formed. The internal capacity of the storage tank with a second circulation pump and batteries forms a heating circuit. Both circuits can circulate different heat transfer fluids, such as water and glycol.
The scheme of a solid fuel boiler with a heat accumulator and a DHW circuit allows for the supply of hot water without the use of double-circuit equipment. For this, internal flow heat exchangers or built-in tanks are used. If hot water is needed throughout the day, we recommend buying and installing a heat accumulator with a flow exchanger. For peak one-time consumption, batteries with hot water tanks are optimal.
Bivalent and multivalent connection schemes have also been developed - they provide for the use of several heat sources at once for heating operation. For this, heat accumulators with several heat exchangers can be used.
Popular Models
It's time to deal with the most popular models of heat accumulators for heating systems. We will consider the products of domestic and foreign manufacturers.
The manufacturer of Prometheus heat accumulators is the Novosibirsk company SibEnergoTerm. It produces models with a volume of 230, 300, 500, 750 and 1000 liters. The equipment warranty is 5 years. Heat accumulators are endowed with four outlets for connection to heating and heat sources. For the conservation of the accumulated energy, a layer of thermal insulation made of mineral wool is responsible. Working pressure is 2 atm., Maximum - 6 atm. When buying equipment, consider its dimensions - for example, the diameter of a 1000-liter model is 900 mm, which is why its body may not fit in standard doorways 80 cm wide.
The price of the presented heat accumulator for heating systems varies in the range from 65 to 70 thousand rubles.
Another capacious heat accumulator for 1000 liters of water. It is equipped with one or two smooth-tube heat exchangers, but lacks thermal insulation, which must be taken into account when installing it - it will have to be purchased separately. The case diameter is 790 mm, but if thermal insulation is added to it, then the diameter grows to 990 mm. The maximum temperature in the heating system is +110 degrees, in the DHW circuit - up to +95 degrees.
These heat accumulators are represented by modifications with six or ten connections. There are also terminals for temperature sensors on board. The capacity of the tanks is 960 liters, the working pressure is up to 3 bar. The thickness of the heat-insulating layer is 80 mm. The use of other liquids as a heat carrier, except for water, is not allowed - this applies to both circuits, and not just the heating circuit. If necessary, it is possible to connect several heat accumulators in series into a single cascade.
Homemade heat accumulators
Nothing prevents you from assembling a heat accumulator for a heating system with your own hands - for this you need to make calculations and draw a drawing, focusing on the required capacity. Tanks are constructed from sheet metal 1-2 mm thick, cut with a plasma cutter, cutting machine or welding machine. Heat exchangers are organized from metal straight or corrugated pipes. And in order to avoid rapid corrosion of the metal, it is necessary to purchase a magnesium anode. Basalt wool can be used as thermal insulation.
As a bonus, we present a detailed drawing of a heat accumulator with a capacity of 500 liters - this is enough to maintain the heating system in a small house.
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