Thermal accumulator for heating. Heating with heat accumulator at night electricity tariff Warm water accumulator for home

Solid fuel boiler systems cannot operate for a long time without human intervention, who must periodically load firewood into the firebox. If this is not done, the system will begin to cool down and the temperature in the house will drop. In the event of a power outage when the furnace is fully ignited, there is a danger of boiling of the coolant in the jacket of the unit and its subsequent destruction. All these problems can be solved by installing a heat accumulator for heating boilers. It will also be able to perform the function of protecting cast iron installations from cracking when there is a sharp change in the temperature of the supply water.

Connecting a solid fuel boiler with a heat accumulator

Calculation of the buffer tank for the boiler

The role of the heat accumulator in general scheme heating system is as follows: during the operation of the boiler in normal mode, accumulate thermal energy, and after the firebox extinguishes, release it to the radiators for a certain period of time. Structurally, a heat accumulator for a solid fuel boiler is an insulated water container of rated capacity. It can be installed both in the furnace room and in a separate room of the house. It makes no sense to place such a tank outside, since the water in it will cool much faster than inside the building.

Taking into account the availability of free space in the house, the calculation of a heat accumulator for a solid fuel boiler in practice is carried out as follows: The capacity of the tank is taken from the ratio of 25-50 liters of water per 1 kW of power required to heat the house. For more accurate calculation buffer tank for the boiler, it is assumed that the water in the tank will heat up to 90 ⁰C during operation of the boiler installation, and after turning off the latter it will release heat and cool down to 50 ⁰C. For a temperature difference of 40 ⁰C, the heat output values ​​for different tank volumes are presented in the table.

Table of heat output values ​​for different tank volumes

Even if there is space in a building to install a large tank, it does not always make sense. It should be remembered that a large amount of water will need to be heated, then the power of the boiler itself should initially be 2 times greater than what is needed to heat the home. A tank that is too small will not perform its functions, as it will not be able to accumulate enough heat.

The selection of a heat accumulator for a solid fuel boiler is influenced by the availability of free space in the room. When purchasing a large storage tank, you will need to provide a foundation, since equipment with a significant mass cannot be placed on ordinary floors. If, according to calculations, a tank with a volume of 1 m3 is required, and there is not enough space for its installation, then you can purchase 2 products of 0.5 m3 each, placing them in different places.

Heat accumulator for solid fuel boiler

Another point is the presence of a hot water system in the house. In the case where the boiler does not have its own water heating circuit, it is possible to purchase a heat accumulator with such a circuit. Of no small importance is the value of the operating pressure in the heating system, which residential buildings traditionally should not exceed 3 Bar. IN in some cases the pressure reaches 4 bar if a powerful heat source is used homemade unit. Then the heat accumulator for the heating system will have to be selected in a special design - with a torispherical cover.

Some factory hot water accumulators are equipped with an electric heating element installed in the upper part of the tank. This technical solution will not allow the coolant to completely cool down after stopping the boiler, the upper zone of the tank will be heated. There will be a supply of hot water for household needs.

Simple switching circuit with mixing

The storage device can be connected to the system by different schemes. The simplest connection of a solid fuel boiler with a heat accumulator is suitable for working with gravity coolant supply systems and will operate in the event of a power outage. To do this, the tank must be installed above the heating radiators. The scheme includes circulation pump, thermostatic three-way valve and check valve. At the beginning of the heating cycle, water, driven by the pump, flows through the supply pipe from the heat source through the three-way valve to the heating devices. This continues until the supply temperature reaches a certain value, for example 60 ⁰C.

At this temperature, the valve begins to mix cold water into the system from the lower pipe of the tank, maintaining at the outlet set temperature 60 ⁰С. Through the upper pipe, directly connected to the boiler, heated water will begin to flow into the tank, and the battery will begin to charge. When the wood in the firebox is completely burned, the temperature in the supply pipe will begin to drop. When it drops below 60 ⁰C, the thermostat will gradually shut off the supply from the heat source and open the flow of water from the tank. That, in turn, will gradually fill up cold water from the boiler and at the end of the cycle the three-way valve will return to its original position.

The check valve, connected in parallel to the three-way thermostat, comes into operation when the circulation pump stops. Then the boiler with the heat accumulator will work directly, the coolant will go to the heating devices directly from the tank, which will be replenished with water from the heat source. In this case, the thermostat does not take part in the operation of the circuit.

Hydraulic split circuit

Another, more complex connection scheme involves an uninterrupted supply of electricity. If this cannot be ensured, then it is necessary to provide for connection to the network through an uninterruptible power supply. Another option is to use diesel or gasoline power plants. In the previous case, the connection of the heat accumulator to the solid fuel boiler was independent, that is, the system could operate separately from the tank. In this scheme, the battery acts as a buffer tank (hydraulic separator). A special mixing unit (LADDOMAT) is built into the primary circuit, through which water circulates when the boiler is ignited.

Connecting a heat accumulator to a solid fuel boiler

Block elements:

• circulation pump;
• three-way thermostatic valve;
• check valve;
• sump;
• Ball Valves;
• temperature control devices.

Differences from the previous scheme - all devices are assembled into one block, and the coolant goes into the tank, and not into the heating system. The operating principle of the stirring unit remains unchanged. This connection of a solid fuel boiler with a heat accumulator allows you to connect as many heating branches as you like at the outlet of the tank. For example, to power radiators and floor or air system heating. Moreover, each branch has its own circulation pump. All circuits are separated hydraulically, excess heat from the source is accumulated in the tank and used when necessary.

Advantages and disadvantages

Heating system with a heat accumulator, in which the heat source is solid fuel installation, has a lot of advantages:

• Increasing comfortable conditions in the house, since after the fuel is burned, the heating system continues to heat the house with hot water from the tank. No need to get up in the middle of the night and load a portion of firewood into the firebox.
• The presence of the container protects the boiler water jacket from boiling and destruction. If the electricity is suddenly turned off or the thermostatic heads installed on the radiators turn off the coolant because the desired temperature has been reached, the heat source will heat the water in the tank. During this time, the electricity supply may be restored or the diesel generator will be started.
• The supply of cold water from the return pipeline to the hot cast iron heat exchanger is excluded after the circulation pump is suddenly turned on.
• Heat accumulators can be used as hydraulic separators in a heating system (hydraulic arrows). This makes the operation of all branches of the circuit independent, which provides additional savings in thermal energy.

The higher cost of installing the entire system and the requirements for equipment placement are the only disadvantages of using storage tanks. However, this investment and inconvenience will be followed by minimal operating costs in the long run.

When heating a house, it often happens that during the daytime it is possible to generate heat in excess, but at night there is not enough of it. There is also the exact opposite situation, in which it is more profitable to use heating at night. A heat accumulator for heating will help smooth out such moments. But you need to know how to select it correctly, install it and connect it to the system. You can get detailed information on this topic from this article.

When is a heat accumulator needed?

This simple element heating system It is recommended to install it in the form of an insulated water tank in the following cases:

• for the most efficient operation of a solid fuel boiler;
• together with an electric heat generator operating at a reduced night tariff.

For reference. There are also water heat accumulators for greenhouses used to preserve solar energy received during the day.

The operation of solid fuel boilers has its own characteristics. The heat generator operates with high efficiency only when operating at maximum modes; if you cut off the air to it to lower the temperature in the furnace, then the operating efficiency also decreases. The homeowner also has a lot of worries about the frequency of heating, the firewood has burned out - he needs to load new ones, which is extremely inconvenient to do in the middle of the night. The solution is simple: you need a storage tank that accumulates previously generated heat for use after the firewood burns out in the firebox.

The opposite situation occurs with an electric boiler connected to the network through a multi-tariff meter. To save money, you need to get maximum heat at night, when the tariff is low, and not use electricity during the day. And here the heat accumulator in the heating system will allow you to organize an optimal operating schedule for the heat source, supplying hot water to the system while the heat generator is inactive.

Important. To work together with a heat accumulator, the boiler must have at least one and a half reserve thermal power. Otherwise, it will not be able to simultaneously heat the water in the heating system and the storage tank.

A similar situation with excess heat occurs in greenhouses; they are even ventilated during the daytime. In order to accumulate solar energy for use at night, you can use the simplest heat accumulator Lezhebok to heat the ground. This is a black polymer sleeve filled with water and laid directly over the bed; it prevents the soil from cooling at night. To absorb more heat, barrels of water painted black are placed inside the greenhouse.

Heat accumulator calculation

A container for storing thermal energy can be either purchased ready-made or made independently. But a logical question arises: how big should the tank be? After all, a small tank will not give the desired effect, and too large will cost a pretty penny. The answer to this question will help you find the calculation of the heat accumulator, but first you need to determine the initial parameters for the calculations:

• heat loss of the house or its square footage;
• duration of inactivity of the main heat source.

Let us determine the capacity of the storage tank using the example of a standard house with an area of ​​100 m2, which requires an amount of heat of 10 kW to heat. Let’s assume that the boiler’s net downtime is 6 hours, and the average coolant temperature in the system is 60 °C. Logically, during the period of time while the heating unit is inactive, the battery should supply 10 kW to the system every hour, for a total of 10 x 6 = 60 kW. This is the amount of energy that should be accumulated.

Since the temperature in the tank should be as high as possible, for calculations we will take a value of 90 ° C; household boilers are still incapable of anything more. The required capacity of a heat accumulator, expressed in mass of water, is calculated as follows:

• m = Q / 0.0012 Δt

In this formula:

• Q is the amount of accumulated thermal energy, for us it is 60 kW;
• 0.0012 kW / kg ºС is specific heat water, in more conventional units of measurement - 4.187 kJ / kg ºС;
• Δt – difference between the maximum temperature of the coolant in the tank and the heating system, ºС.

So, the water accumulator should hold 60 / 0.0012 (90 – 60) = 1667 kg of water, which is approximately 1.7 m3 in volume. But there is one point: the calculation is made at the lowest temperature outside, which happens infrequently, excluding the northern regions. In addition, after 6 hours, the water in the tank will only cool down to 60 ºС, which means that in the absence of cold weather, the battery can be “discharged” further until the temperature drops to 40 ºС. Hence the conclusion: for a house with an area of ​​100 m2, a storage tank with a volume of 1.5 m3 will be enough if the boiler is inactive for 6 hours.

From the previous section it follows that you won’t be able to get away with an ordinary 200 liter barrel, unless its capacity is at least half a cube. This is enough for a house with an area of ​​30 m2, and even then not for long. In order not to waste time and effort, you need to

From the point of view of placement in the boiler room, it is better to make a rectangular container. The dimensions are arbitrary, the main thing is that their product is equal to the calculated volume. Perfect option– the tank is made of stainless steel, but ordinary metal will also do.

At the top and bottom, a self-made heat accumulator must be equipped with pipes for connection to the system. To prevent the steel walls from bulging outward under water pressure, the structure must be strengthened with ribs or jumpers.

The battery tank must be properly insulated, including from below. For this purpose, foam plastic with a density of 15-25 kg/m3 or mineral wool in slabs with a density of at least 105 kg/m3 are suitable. The optimal thickness of the thermal insulation layer is 100 mm. The resulting device, filled with coolant, will have a decent weight, so a foundation will be required for its installation.

Advice. If you need a container for a gravity heating system, you should install it yourself on a metal stand, not forgetting to insulate the lower part. The goal is to raise the tank above the level of the batteries.

Connection diagram

After installing the tank in place, it must be correctly connected to the pipeline network. The most popular standard connection diagram for a heat accumulator is shown in the figure:

To implement it, you will need 2 circulation pumps and the same number of three-way valves. Pumps provide circulation in separate circuits, and valves provide the required temperature. In the boiler circuit it should not fall below 55 ºС in order to avoid the appearance of condensation in the solid fuel boiler; this is what the valve on the left side of the diagram does.

The coolant in the heating pipelines is heated depending on the heat demand, and therefore the connection of the heat accumulator on the other side is also carried out through the mixing unit. The valve can control the water temperature automatically, based on a sensor or using a thermostat. One of the diagrams of a heating system with a heat accumulator (buffer tank) is presented in the video.

Conclusion

A heat-accumulating container can significantly make life easier for owners of solid fuel boilers. They won't have to worry about loading fuel at night, which is a big plus. And the heat generator itself will operate in an economical mode, developing the highest efficiency. As for electric boilers, the benefits of installing a storage tank are obvious.

Often, homeowners are unable to buy modern heating equipment, so they are looking for alternative solutions. Take, for example, a buffer tank (otherwise known as a heat accumulator), an indispensable item for heating systems with a solid fuel boiler. A storage tank with a volume of 500 liters costs approximately 600-700 USD. That is, the price of a thousand-liter barrel reaches 1000 USD. e. If you make a heat accumulator with your own hands, and then install the tank in the boiler room yourself, you will be able to save half of the specified amount. Our task is to talk about manufacturing methods.

Where is a heat accumulator used and how is it designed?

A thermal energy storage device is nothing more than an insulated iron tank with pipes for connecting water heating lines. The buffer tank performs 2 functions: it accumulates excess heat and heats the house during periods when the boiler is inactive. The heat accumulator replaces the heating unit in 2 cases:

1. When heating a home or with a boiler that burns solid fuel. The storage tank works for heating at night, after wood or coal burns out. Thanks to this, the homeowner can relax in peace, rather than running to the boiler room. It is comfortable.
2. When the heat source is an electric boiler, and electricity consumption is recorded using a multi-tariff meter. Energy at the night rate is half the price, so during the day the heating system is completely powered by the heat accumulator. It's economical.

Important point. A hot water accumulator tank increases the efficiency of a solid fuel boiler. After all maximum efficiency heat generator is achieved with intense combustion, which cannot be constantly maintained without a buffer tank that absorbs excess heat. The more efficiently wood is burned, the less it is consumed. This also applies gas boiler, whose efficiency decreases in low combustion modes.

A storage tank filled with coolant operates on a simple principle. While the heat generator is heating the rooms, the water in the tank is heated to a maximum temperature of 80-90 ° C (the heat accumulator is charging). After the boiler is turned off, hot coolant from the storage tank begins to flow to the radiators, providing heating for the house for a certain time (the heat battery is discharged). The duration of operation depends on the volume of the tank and the outside air temperature.

The simplest factory-made storage tank for water, shown in the diagram, consists of the following elements:

• the main tank is cylindrical in shape, made of carbon or stainless steel;
• thermal insulation layer 50-100 mm thick, depending on the insulation used;
• outer skin – thin painted metal or polymer cover;
• connecting fittings embedded into the main container;
• immersion sleeves for installing a thermometer and pressure gauge.

Note. More expensive models of heat accumulators for heating systems are additionally equipped with coils for hot water supply and heating from solar collectors. Another useful option is a block of electric heating elements built into the upper zone of the tank.

Factory production of heat storage devices

If you are seriously concerned about installing a heat accumulator and decide to make it yourself, then first you should familiarize yourself with the factory assembly technology.

It is unrealistic to repeat the technological process in a home workshop, but some techniques will be useful to you. At the enterprise, the hot water storage tank is made in the form of a cylinder with a hemispherical bottom and a lid in the following order:

1. Sheet metal 3 mm thick is fed to a plasma cutting machine, where it is used to produce blanks for end caps, housing, hatch and stand.
2. On lathe Main fittings with a diameter of 40 or 50 mm (thread 1.5 and 2”) and immersion sleeves for control devices are manufactured. A large flange for the inspection hatch, about 20 cm in size, is also machined there. A pipe for insertion into the body is welded to the latter.
3. The body blank (the so-called shell) in the form of a sheet with holes for fittings is directed to rollers that bend it to a certain radius. To get a cylindrical container for water, all that remains is to butt weld the ends of the workpiece.
4. A hydraulic press presses hemispherical caps from metal flat circles.
5. The next operation is welding. The order is as follows: first, the body is welded using tacks, then the lids are tacked to it, then all the seams are completely welded. At the end, fittings and an inspection hatch are attached.
6. The finished storage tank is welded to the stand, after which it undergoes 2 permeability tests - air and hydraulic. The latter is produced at a pressure of 8 bar, the test lasts 24 hours.
7. The tested tank is painted and insulated with basalt fiber no less than 50 mm thick. The top of the container is sheathed with thin sheet steel with a colored polymer coating or covered with a thick cover.

Reference. To insulate the tank, manufacturers use different materials. For example, Russian-made Prometheus heat accumulators are insulated with polyurethane foam.

Most factory heat accumulators are designed for a maximum pressure of 6 Bar at a coolant temperature in the heating system of 90 °C. This value is twice the response threshold of the safety valve installed in the safety group of solid fuel and gas boilers (limit - 3 Bar). The production process is shown in detail in the video:

We make a heat battery ourselves

You have decided that you cannot do without a buffer tank and want to make it yourself. Then get ready to go through 5 stages:

1. Calculation of the volume of the heat accumulator.
2. Choosing a suitable design.
3. Selection and preparation of materials.
4. Assembly and leak testing.
5. Installation of the tank and connection to the water heating system.

Advice. Before calculating the volume of the barrel, think about how much space in the boiler room you can allocate for it (in terms of area and height). Clearly decide how long the water heat accumulator should replace the inactive boiler, and only then proceed to the first stage.

How to calculate tank volume

There are 2 ways to calculate the capacity of a storage tank:

• simplified, offered by manufacturers;
• accurate, carried out according to the formula for the heat capacity of water.

The essence of the enlarged calculation is simple: for each kW of boiler plant power, a volume equal to 25 liters of water is allocated in the tank. Example: if the productivity of the heat generator is 25 kW, then the minimum capacity of the heat accumulator will be 25 x 25 = 625 l or 0.625 m³. Now remember how much space is allocated in the boiler room and adjust the resulting volume to the actual size of the room.

Reference. Those who want to weld a homemade heat accumulator often wonder how to calculate the volume of a round barrel. Here it is worth recalling the formula for calculating the area of ​​a circle: S = ¼πD². Substitute the diameter of the cylindrical tank (D) into it, and multiply the result by the height of the tank.

You will get more accurate dimensions of the heat accumulator if you use the second method. After all, a simplified calculation will not show how long the calculated amount of coolant will last under the most unfavorable weather conditions. The proposed method is based on the indicators you need and is based on the formula:

m = Q / 1.163 x Δt

• Q – the amount of heat that needs to be accumulated in the battery, kWh;
• m – estimated mass of coolant in the tank, tons;
• Δt – difference in water temperatures at the beginning and end of heating;
• 1.163 W h/kg °C is the reference heat capacity of water.

Let's explain further with an example. Let's take a standard house of 100 m² with an average heat consumption of 10 kW, where the boiler must be idle for 10 hours a day. Then it is necessary to accumulate 10 x 10 = 100 kWh of energy in the barrel. The initial water temperature in the heating network is 20 °C, heating occurs up to 90 °C. We calculate the mass of the coolant:

m = 100 / 1.163 x (90 - 20) = 1.22 tons, which is approximately 1.25 m³.

note that thermal load 10 kW is taken approximately; in an insulated building with an area of ​​100 m², heat loss will be less. Point two: so much heat is needed on the coldest days, of which there are 5 for the whole winter. That is, a heat accumulator for 1000 liters is sufficient with a large margin, and taking into account the seasonal temperature difference, you can easily keep within 750 liters.

Hence the conclusion: in the formula you need to substitute the average heat consumption for the cold period, equal to half of the maximum:

m = 50 / 1.163 x (90 - 20) = 0.61 tons or 0.65 m³.

Note. If you calculate the volume of the barrel based on the average heat consumption, in severe frosts it will not be enough for the calculated period of time (in our example - 10 hours). But you will save money and space in the furnace room. More information on making payments is presented in.

About the design of the container

To make your own heat accumulator, you will have to defeat one insidious enemy - the pressure exerted by the liquid on the walls of the vessel. Do you think why factory tanks are made cylindrical, and the bottom and lid are hemispherical? Yes, because such a container can withstand the pressure of hot water without additional reinforcement.

On the other hand, few people have the technical ability to form metal on rollers, not to mention drawing semicircular parts. We offer the following ways to resolve the issue:

1. Order a round internal tank from a metalworking enterprise, and carry out the insulation and final installation work yourself. It will still cost less than buying a factory-assembled heat accumulator.
2. Take a ready-made cylindrical tank and make a buffer tank on its base. We will tell you where to get such tanks in the next section.
3. Weld a rectangular heat accumulator from sheet iron and strengthen its walls.

Advice. In a closed heating system with a solid fuel boiler, where excess pressure can jump to 3 Bar or higher, it is strongly recommended to use a cylindrical heat accumulator.

In an open heating system with zero water pressure, you can use a rectangular tank. But do not forget about the hydrostatic pressure of the coolant on the walls; add to it the height of the water column from the container to expansion tank, installed at the highest point. That is why the flat walls of a homemade heat accumulator should be reinforced, as shown in the drawing of a 500 liter capacity tank.

A properly reinforced rectangular storage tank can also be used in a closed heating system. But in the event of an emergency pressure surge from overheating of the TT boiler, the tank will leak with a 90% probability, although you may not notice a small crack under the insulation layer. Watch the video to see how the unstrengthened metal of the vessel bulges when filled with water:

Reference. It makes no sense to weld directly onto the walls stiffeners made of corners, channels and other rolled metal. Practice shows that the pressure force bends corners of a small section along with the wall, and tears off large ones at the edges.

Making a powerful frame from the outside is impractical, the consumption of materials is too high. A compromise option is the internal spacers shown in the drawing of a homemade heat accumulator.

Selection of materials for the tank

You will make your task much easier if you find a ready-made cylindrical tank, initially designed for a pressure of 3–6 bar. What containers can be used:

• propane cylinders of different capacities;
• discarded process tanks, for example, receivers from industrial compressors;
• receivers from railway cars;
• old iron boilers;
• internal tanks of containers for storing liquid nitrogen, made of stainless steel.

Note. In extreme cases, a steel pipe of suitable diameter will do. Flat covers can be welded to it, which will have to be reinforced with internal braces.

To weld a square tank, take sheet metal 3 mm thick, no more is needed. Make of rigidity round pipesØ15-20 mm or profiles 20 x 20 mm. Select the size of the fittings according to the diameter of the boiler outlet pipes, and for cladding, buy thin steel (0.3-0.5 mm) with powder painting.

A separate question is how to insulate a heat accumulator that you welded yourself. The best option– basalt wool in rolls with a density of up to 60 kg/m³ and a thickness of 60-80 mm. Polymers such as polystyrene foam or extruded polystyrene foam should not be used. The reason is mice that love warmth and in the fall can easily settle under the lining of your storage tank. Unlike polymer insulation, they do not chew basalt fiber.

Now we will indicate other options for ready-made vessels that are not recommended for use for heat accumulators:

1. An improvised tank made from a Eurocube. Such plastic containers are designed for a maximum content temperature of 70 °C, but we need 90 °C.
2. Heat accumulator made of an iron barrel. Contraindications: thin metal and flat tank lids. Instead of strengthening such a barrel, it is easier to take a good steel pipe.

Assembly of a rectangular heat accumulator

We would like to warn you right away: if you have mediocre welding skills, then it is better to order the manufacture of the tank externally according to your drawings. The quality and tightness of the seams is of great importance; at the slightest leak, the storage container will leak.

For a good welder there will be no problems here, you just need to understand the order of operations:

1. Cut metal blanks to size and weld the body without a bottom and a lid using tacks. To secure the sheets, use clamps and a square.
2. Cut holes in the side walls for the stiffeners. Insert the prepared pipes inside and scald their ends from the outside.
3. Grab the bottom and lid to the tank. Cut holes in them and repeat the operation with the installation of internal braces.
4. When all the opposite walls of the container are securely connected to each other, begin continuous welding of all seams.
5. Install supports from pipe sections at the bottom of the tank.
6. Insert the fittings at a distance of less than 10 cm from the bottom and lid, as shown in the photo below.
7. Weld metal brackets to the walls, which will serve as brackets for attaching the insulating material and sheathing.

Advice on installing internal struts. To ensure that the walls of the heat accumulator effectively resist bending and do not break due to welding, extend the ends of the stretch marks outward by 50 mm. Then additionally weld stiffeners from a steel sheet or strip to them. ABOUT appearance don’t worry, the ends of the pipes will then disappear under the cladding.

A few words about how to insulate a heat accumulator. First, check it for leaks by filling it with water or lubricating all the seams with kerosene. Thermal insulation is quite simple:

• clean and degrease all surfaces, apply primer and paint to protect them from corrosion;
• wrap the tank with insulation without squeezing it, and then secure it with a cord;
• cut the facing metal, make holes in it for the pipes;
• Screw the casing to the brackets with self-tapping screws.

Screw the cladding sheets so that they are connected to each other with fasteners. That's it for making a homemade heat accumulator for open system heating is finished.

Installation and connection of the tank to heating

If the volume of your heat accumulator exceeds 500 liters, then it is not advisable to place it on a concrete floor; it is better to arrange a separate foundation. To do this, dismantle the screed and dig a hole to a dense layer of soil. Then fill it with broken stone (rubble), compact it and fill it with liquid clay. Pour a 150 mm thick reinforced concrete slab in wooden formwork on top.

The correct operation of a heat accumulator is based on the horizontal movement of hot and cooled flow inside the tank when the battery is “charging”, and the vertical flow of water during “discharging”. To organize such battery operation, you need to perform the following steps:

• the circuit of a solid fuel or other boiler is connected to a water storage tank through a circulation pump;
• the heating system is supplied with coolant using a separate pump and mixing unit with a three-way valve that allows it to be taken from the battery required amount water;
• the pump installed in the boiler circuit should not be inferior in performance to the unit supplying coolant to the heating devices.

The standard connection diagram for a heat accumulator with a TT boiler is shown above in the figure. The balancing valve on the return line serves to regulate the coolant flow based on the water temperature at the inlet and outlet of the tank. Our expert Vladimir Sukhorukov will tell you how to properly strap and set up in his video:

Reference. If you live in the capital of the Russian Federation or the Moscow region, then regarding the connection of any heat accumulators, you can consult personally with Vladimir, using the contact information on his official website.

Budget storage tank made from cylinders

For those homeowners whose boiler room area is very limited, we suggest making a cylindrical heat accumulator from propane cylinders.

The 100 l design, developed by another of our masters, is designed to perform 3 functions:

• unload the solid fuel boiler when overheating, taking in excess heat;
• heat water for household needs;
• provide heating of the house for 1-2 hours in case of extinguishing of the TT boiler.

Note. The battery life of the heat accumulator is short due to its small volume. But it will fit in any furnace room and will be able to remove heat from the boiler after a power outage, since it is connected directly, without a pump.

To assemble the storage tank you will need:

• 2 standard propane cylinders;
• at least 10 m of copper tube Ø12 mm or stainless corrugation of the same diameter;
• fittings and sleeves for thermometers;
• insulation – basalt wool;
• painted metal for cladding.

You need to unscrew the valves from the cylinders and cut off the caps with a grinder, filling them with water to prevent the remaining gas from exploding. We carefully bend the copper tube into a coil around another pipe of a suitable diameter. Then we proceed like this:

1. Using the presented drawing, drill holes in the future heat accumulator for pipes and sleeves for thermometers.
2. Secure by welding several metal brackets inside the cylinders for mounting the DHW heat exchanger.
3. Place the cylinders one on top of the other and weld them together.
4. Install a coil inside the resulting tank, releasing the ends of the tube through the holes. Use gland packing to seal these areas.
5. Attach the bottom and lid.
6. Insert an air vent into the lid and a drain valve into the bottom.
7. Weld the brackets to secure the casing. Make them different lengths to ready product had a rectangular shape. It will be inconvenient to bend the cladding in a semicircle, and it will not be aesthetically pleasing.
8. Insulate the tank and fasten the casing with self-tapping screws.

The design feature of this heat accumulator is that it is connected to a solid fuel boiler directly, without a circulation pump. Therefore, for docking they use steel pipesØ50 mm, laid with a slope, the coolant circulates by gravity. To supply water to the heating radiators, a pump + three-way mixing valve is installed after the buffer tank.

Conclusion

On many Internet resources there is a statement that making a heat accumulator with your own hands is a piece of cake. If you study our material, you will understand that such statements are far from reality; in fact, the issue is quite complex and serious. You can’t just take a barrel and attach it to a solid fuel boiler. Hence the advice: think carefully about all the nuances before starting work. And without a welder’s qualifications, it’s not worth taking on a buffer tank; it’s better to order it from a specialized workshop.

Heating with wood or coal is not very pleasant. You have to heat it often, especially in cold weather; it takes a lot of time and effort. In addition, the fluctuating temperature - sometimes cold, sometimes hot - does not bring joy either. These problems can be solved by installing a heat accumulator (heat accumulator) for heating.

What is a heat accumulator for heating?

In the simplest case, a heat accumulator for a heating system is a container filled with coolant (water). This container is connected to the heating water boiler and to the heating system (through pipes of a suitable diameter). In more complex devices, a heat exchanger is located inside the container, connected to the heating boiler. The hot water supply comb can also be powered from this container through another heat exchanger.

Heat accumulators for heating are usually made of steel - regular, structural or stainless steel. They can be cylindrical or parallelepiped-shaped (square). Since they are designed to retain heat, much attention is paid to insulation.

What is it needed for

Installation of a thermal accumulator (TA) for individual heating can solve several problems at once. Most often, TAs are placed where they are heated with wood or coal. In this case, the following tasks are solved:

• A water tank is a guarantee that the water in the system will not overheat (if the length of the heat exchanger and the tank capacity are correctly calculated).
• Using the heat accumulated in the coolant, normal temperature is maintained after the fuel load has burned out.
• Due to the fact that there is a reserve of heat in the system, you need to heat it less often.

All these considerations force you to buy a very expensive heat accumulator for heating.

Some craftsmen make. This is an economical option, but it also costs at least 20-50 thousand rubles. With a purchased TA you will have to spend many times more than with a homemade one.

Heat accumulators are not cheap, but the result of their use is worth it. Firstly, it increases safety (the heating system will not boil, pipes will not burst, etc.). Secondly, you won’t have to heat it so often. Thirdly, a more stable temperature, since the container with water is a buffer that smoothes out temperature fluctuations that characterize heating with wood and coal (it’s hot, then it’s cool). Therefore, these devices are also called “ buffer capacity for heating."

Connecting two boilers via a buffer tank is easy and simple

Separately, it is worth mentioning the saving of firewood and coal. In a heating system without TA, on relatively warm days it is necessary to limit the access of air, reducing the combustion intensity. Otherwise the house is too hot. Since conventional solid fuel (SF) boilers are not particularly designed for such modes, the efficiency of the boiler in this case is very low. Most of the heat simply flies into the chimney. In the case of an installed water heat accumulator, everything is exactly the opposite: you do not need to limit combustion. The faster the water heats up, the better. It is only important to correctly calculate the system parameters.

Another option is a heat accumulator for heating with a built-in tubular electric heater (TEH). This makes it possible to further increase the time between starts of the solid fuel boiler. Moreover, if there is a night tariff in your region, you can turn on the electric heating at night. Then it won’t hurt your wallet so much. You can also solve the problem of insufficient power of the selected and installed heating boiler.

There are other areas of application. For example, some owners install two boilers. To reserve just in case, since one type of fuel is not always available. This practice is quite common. Connecting them via a heat accumulator greatly simplifies the wiring. There is no need to install a lot of shut-off and control valves. Put the boilers into a heat accumulator - and that’s all there is to it. By the way, you can connect to the same container. They also easily fit into such a scheme. By the way, the heat stored on a sunny day with the help of solar collectors can be heated for up to two days.

Owners of electric boilers install a buffer tank to save money. Yes, this increases the volume of coolant that has to be heated, but the boiler is started during the reduced tariff - at night. During the day, the temperature is simply maintained by the heat that is “stored” in the heat accumulator. How profitable this method is depends on the region. In some regions, night rates are significantly lower than day rates, i.e. It is quite possible to make heating cheaper.

How to calculate the volume of TA

In order for a heat accumulator for heating to perform its functions, its volume must be selected correctly. There are several methods:

• by heated area;
• by boiler power;
• according to the time available.

Most of the methods are based on experience. For this reason, there is a “fork” in the recommendations. For example, from 35 to 50 liters per square meter of heated area. How exactly to determine the number? It is worth taking into account the region of residence and the degree of insulation of the house. If you live in a region with not the most severe winters or the house is well insulated, it is better to take it at the lower limit or so. Otherwise - on the top.

When choosing the volume of a heat accumulator for heating, two points must also be taken into account. The first is that a large amount of water will allow you to heat it much less often. Due to the stored heat, the temperature can be maintained for a long time. But, on the other hand, the time it takes to “accelerate” this volume to the required temperature greatly increases (heating to 85-88°C is considered normal). In this case, the system becomes very inertial. You can, of course, take a more powerful boiler, but paired with a buffer tank, this will cost a considerable amount. Therefore, you have to maneuver, finding the optimal solution.

By heated area

You can select the volume of the heat accumulator for the heating system according to the area of ​​the room. It is believed that by ten square meters 35 to 50 liters are required. The selected value is multiplied by the quadrature divided by ten to obtain the desired volume.

For example, in the heating system of a house with an area of ​​120 m² with average insulation, it is better to install a heat accumulator for heating 120 m² / 10 * 45 l = 12 * 45 = 540 liters. This will not be enough for the Middle Zone, so you should look at containers with a volume of approximately 800 liters.

In general, to make it easier to navigate, for a house with an area of ​​160-200 square meters, located in Middle lane, with average insulation, the optimal tank volume is 1000-1200 liters. Yes, with such a volume, you will have to heat it more often in cold weather. But this will not undermine your budget too much, and will allow you to live quite comfortably almost all winter.

By boiler power

Since the boiler will have to work on heating the water in the tank, it makes sense to calculate the volume based on its capabilities. In this case, 50 liters of capacity are taken per 1 kW of power.

You can make it even simpler - use the table (the values ​​that are optimal in terms of cost and performance are shaded in yellow)

The calculation is simple. For a 20 kW boiler, a TA of 1000 liters is suitable. With such a volume of heat storage for heating, you will have to heat it twice a day.

According to the desired duration of downtime and heat loss

This method is more accurate, as it allows you to select dimensions specifically for the parameters of your home (heat loss) and your wishes (duration of downtime).

Let's calculate the volume of a heat accumulator for a house with a heat loss of 10 kW/hour and an idle time of 8 hours. We will heat the water to 88 °C, and it will cool down to 40 °C. The calculation is as follows:

For these conditions, required capacity thermal accumulator for heating - 1500 liters. This is because heat loss of 10 kW/hour is too much. This is a house with virtually no heating.

Types of buffer tanks, features of their use

We will talk about the “filling” of heat accumulators for heating. Outwardly, they all look the same, but the inside may be completely empty, or there may be heat exchangers. Usually this is a pipe - smooth or corrugated - twisted into a spiral. It is by the presence, quantity and location of these spirals that a heat accumulator for heating is distinguished.

Buffer tanks for heating systems come with different “fillings”

Without heat exchanger

Essentially, it is just a thermally insulated tank with direct connection to the boiler and consumers. Such a heat accumulator can be used in systems where the same coolant is acceptable. For example, you can’t connect the hot water supply like that. Even if water is used as a coolant, its composition is far from drinking water or even that which can be used for domestic needs. As a technical one, it’s possible, but not in all cases.

The second limitation is the pressure on consumers. In any operating mode, the operating pressure of consumers must be no lower than the pressure in the boiler and the tank itself. Since the system is single, the pressure will be common. Everything is clear here and no explanation is required.

The third limitation is temperature. The maximum temperature at the boiler outlet should not exceed the permissible temperatures of all other system components. This also requires no explanation.

A heat accumulator without a heat exchanger is simply a sealed insulated container with pipes for connecting the boiler and consumers

Basically, this is the most cheap option heat accumulator for heating, but the choice is not the best. The fact is that the boiler heat exchanger will not last long. The entire considerable volume of water will be pumped through it and a considerable amount of salts will be deposited. And if there is also a water consumption - as a hot water supply - then the source of salts will become inexhaustible, as it will be replenished with fresh water from the tap. So we install a heat accumulator without a heat exchanger as a last resort - if we really don’t have the funds for more expensive devices.

With a heat exchanger in the lower or upper part of the tank, with two (bivalent)

Installing a heat exchanger connected to the boiler solves many problems. A small volume of coolant circulates through this circle and does not mix with the rest. So a lot of salts will not be deposited on the boiler heat exchanger. In addition, problems with pressure and temperature are eliminated. Since the circuit is closed, the pressure in it does not affect the rest of the system and can be any within a reasonable range.

Temperature restrictions remain: it is important that the coolant does not boil. But this can be solved - there are special ways to solve it.

But where is it better to install the heat exchanger from the boiler in the heat accumulator - at the top or at the bottom? If you place it at the bottom, there will be constant movement in the container. The heated coolant will rise up, the colder one will fall down. This way all the water in the container will be more or less the same temperature. This is good if you need the same temperature for all consumers. In such cases, heat accumulators with a lower heat exchanger are chosen.

If the boiler spiral is located in the upper part, the coolant is heated layer by layer. The most heat It turns out in the upper part, gradually decreasing downwards. This temperature stratification can be useful if you supply water at different temperatures. For example, you can feed it hotter into radiators. The pipes going to them must be connected to the topmost terminals. The heated floor needs a warm coolant - we take it from the middle. So this is a good option too.

There are also heat accumulators with two heat exchangers. Outputs from different heat sources are connected to them. This can be two boilers, boiler + solar collectors, other options. Here you just have to decide which source to connect up and which down. In some TA models, spiral heat exchangers are nested one inside the other. Then everything is simpler - you figure out which source can heat the larger volume, and connect it to an external heat exchanger. The second is to the internal.

Options for DHW

Installing a heat accumulator solves the problem of hot water supply. There are several ways to provide water heating for technical needs.

As already mentioned, heated water can be taken directly from the tank. But its quality will be technical. Do you want to use this for showering, bathing, washing dishes - no questions asked. No - you will have to install a heat accumulator with a special heat exchanger, connect it to a cold water comb, and tie it up. But the water will be of proper quality.

Another option is a heat accumulator with a built-in hot water tank. It is used for those cases when warm water is needed at a time when the coolant is not actively heated. The tank located in the upper part retains heat, so that even when the rest of the volume cools down, the water remains warm. Tanks can be additionally equipped with heating elements. This will make it possible to have water at the desired temperature in any case.

What are the benefits of a heat accumulator for heating with a built-in hot water tank? Space is saved. To place a heat exchanger and an indirect heating boiler next to each other will require much more space. The second advantage is that there are small cost savings. Minus - if the buffer tank fails, you lose both hot water and heating.

When designing a heating system, the main goals are comfort and reliability. The house should be warm and cozy, and for this, hot coolant should always flow into the radiators without delays or temperature surges.

This is difficult to achieve with a solid fuel boiler, 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 correct the situation.

With a simple design and principle of operation, it can eliminate a number of inconveniences and disadvantages classical scheme heating.

Why is it needed?

The heat accumulator is a well-insulated large-capacity tank filled with coolant and water. Due to the high heat capacity of water, when the entire volume is heated, a significant reserve 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 coolant in the heating circuit, the heat capacity and, accordingly, the inertia of the entire system. Heating the entire volume will require more energy and time with limited heating power, but the battery will also take a very long time to cool down. If necessary, hot water from the battery can be supplied to the heating circuit and maintain a comfortable temperature in the house.

To evaluate the benefits of a heat accumulator, it is easiest to consider several situations first:

• 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 drops again and so the cycle repeats. As a result, the water temperature in the circuit constantly fluctuates over a fairly wide 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 decoupling will be required, preferably with automatic control;
• Solid fuel boiler, even long burning, constantly requires the user's attention. As soon as you miss the time for adding a new portion of fuel, the coolant in the heating circuit is already beginning to cool down, like the whole house;
• Often the maximum boiler power 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, and an uncompromising one at that. 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 a coil or pipe register as a heat exchanger;
• with built-in boiler tank.

With a full body kit, the heat accumulator is capable of:

Calculation

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 capacity 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 = m*C*(T2-T1);
• m – mass, kg;
• C – specific heat capacity W/kg*K;
• (T2-T1) – temperature delta, final and initial.

If the water in the boiler and, accordingly, in the heating element is heated to 90ºС, and the lower threshold is taken equal to 50ºС, then the delta is equal to 40ºС. If we take TA water as filling, then one ton of water, when cooled to 40ºC, releases approximately 46 kW*hours of heat.

The stored energy should be sufficient for the intended use of the heat accumulator.

To select the required volume of the heat accumulator, it is necessary to determine:

• The time during which the accumulated energy in the heat exchanger should be enough to cover the heat loss of the house;
• The time during which the coolant in the heat exchanger must heat up;
• Power of the main heat source.

For periodic operation of the boiler during the day

If it is needed to switch the boiler operation only to night or day mode, when heat is supplied for a limited time, then the TA power should be enough to cover the heat loss of the house for the remaining time. At the same time, the boiler’s power should be enough to heat the heating unit in a timely manner and, again, to heat the house.

Let's assume that a solid fuel boiler is used with firewood only during the day for 10 hours, the estimated heat loss of the house for the coldest period of the year is 5 kW. 120 kW*hours are required per day for full heating.

The battery is used for 14 hours, which means that it needs to accumulate 5 kW * 14 hours = 70 kW * hours of heat. If you take water as a coolant, you will need 1.75 tons or a heat exchange volume of 1.75 m3. It is important that the boiler must produce all the necessary heat within just 10 hours, that is, its power must be more than 120/10 = 12 kW.

If the heat accumulator is used as a backup option in case of boiler failure, then the stored energy should be enough for at least a day or two to cover all heat losses in the house. If we take the same 100 m2 house as an example, then heating it will require 240 kW*hours in two days, and a heat accumulator filled with water must have a volume of at least 5.3 m3.

But in this case, the TA does not necessarily have to heat up in a short period of time. A boiler power reserve of one and a half is enough to accumulate the required amount of heat in a week or two.

The calculation is approximate, without taking into account the reduction in the thermal power of radiators depending on the temperature of the coolant and air in the room.

In the simplest case, the heat accumulator is connected in series between the boiler and the heating circuit. A circulation pump is installed between the heat exchanger and the boiler so that hot water flows into top part TA, pushing cold water from the bottom into the boiler. A circulation pump is installed between the heat exchanger and the heating circuit to draw hot water from the upper part and transport it to the radiators.

However, this significantly increases the overall heat capacity of the system, and when starting the heating initially, you will have to wait until the entire volume of the heat exchanger is heated before the heat reaches the radiators.

Another option for switching on is parallel to the heating boiler. This option works well in combination with a gravity heating system. The upper outlet of the heat accumulator is connected to the highest point of the distribution box, and at the lower point - to the boiler.

The disadvantages are the same as in the first case; the entire volume of coolant in the system and in the heater is heated, which significantly increases the time to start heating.

The only advantages are ease of connection and a minimum of elements used.

Switching scheme with mixing

The best thing use a switching circuit with mixing or hydraulic isolation. Three-way valves with a thermostat are used. The heat accumulator is installed as a separate element of the system, parallel to the heating circuit.

The main part of the automation is installed on the supply pipeline: three-way valve, thermostats, safety group, etc. By default, the three-way valve directs the coolant from the boiler to the radiators until the room temperature reaches the required level.

As soon as there is no need for active heating, the valve transfers part of the coolant from the boiler to the heat accumulator, discharging excess heat.

When the maximum water temperature in the heater and the target temperature in the radiators are reached, the overheating sensor installed in the boiler is triggered and it turns off. While heating is required or the heat accumulator is not warmed up, the boiler continues to operate.

If for some reason the boiler stops producing rated power or switches off completely when the temperature on the supply line drops, water from the heat accumulator is mixed into the heating circuit, replenishing the heat loss of the system.

You can use several three-way valves on the supply and return lines and a group of thermostats. As an option, ready-made assemblies for connecting heat accumulators are available for sale - an automatic mixing unit, for example LADDOMAT.

With your own hands

If you really want, you can build a storage tank with your own hands. Ideally she should:

• withstand the nominal pressure in the system with a reserve;
• have a calculated volume;
• be protected from corrosion and high temperatures;
• be completely sealed.

For manufacturing, you should take sheet steel, preferably stainless steel with a thickness of at least 3 mm, taking into account the total load and pressure.

The standard TA shape is a tall cylinder with a semicircular base and lid. The ratio of diameter to height is selected to be approximately 1 to 3-4 to promote better heat distribution inside the container.

In this case, hot water is taken from the highest point to the radiators. Just above the center, the water is diverted to the heated floor circuit, and at the lowest point of the TA the return line is connected to the heating boiler.

It is almost impossible to weld a cylindrical container yourself. It is easier to build a parallelepiped with a similar configuration and aspect ratio. All corners should be further strengthened.

The container must be insulated. For this, it is better to use basalt or mineral wool with a thickness of at least 150 mm to reduce heat loss through the walls.

To install the heat accumulator, you should prepare a special support platform, foundation, capable of supporting the enormous weight of equipment. Even the battery itself can weigh up to 400-500 kg. If its volume is, for example, 3 cubic meters, then when filled its weight will exceed 3.5 tons.

Russian made

There are not many domestically produced heat accumulators on the Russian market, since only recently they began to be actively introduced into autonomous heating systems.