Currently, during the period of constant increase in prices for main types of energy resources, the issue of energy saving and the use of highly economical heating systems is of particular relevance. The efficiency of heating systems is especially important for country cottages, which use liquid or solid fuel boilers as a heat source.

Typically, the heating system of a private home includes:

• heating boiler running on various types fuel or electricity;
• main pipeline system;
• heating radiators (convectors).

To increase energy efficiency and reduce fuel consumption, modern heating systems include thermal accumulators (heat accumulators). This device is a large-volume container that is included in the heating system and has different design and implementing different ways heat exchange.

Today, industry produces a variety of thermal energy storage devices for household purposes. However, most of them have a high cost, a rather complex connection and the need to insert additional devices into the heating system (temperature sensors, manual and controlled valves, as well as other devices).

At the same time, today there are a sufficient number of homemade designs of heat accumulators that you can make and connect with your own hands. At the same time, their cost if manufactured independently will be much cheaper, and in terms of functionality they are not much inferior to factory designs.

Purpose and functionality of a heat accumulator

The use of heat accumulators is not justified for all types of systems. In the West, they are often used as part of solar heaters. In Russian private homes they are mainly used in the following two cases:

• when connecting an electric heating boiler to a multi-tariff boiler, when at night the electric heater is turned on at full power and the battery effectively accumulates heat, and during the day the living space is heated using the accumulated energy, and the boiler is turned on only to maintain a certain temperature level;
• when heating a home with a solid fuel boiler, when due to the thermal energy accumulated during the day there is a constant surge coal or firewood is not required at night and the heater operates in economical mode.

In addition, the inclusion of a heat accumulator in the heating system can significantly expand it functionality, the main of which can be considered:

• implementation of hot water supply for residential premises;
• stabilization of the temperature regime and microclimate of residential premises;
• a significant increase in the energy efficiency of the heating system, which makes it possible to reduce energy use costs;
• allows you to combine several different types of heaters into a single one heating system;
• implementation of the possibility of accumulating excess thermal energy generated by the heating boiler.

Designs of factory-made heat accumulators

Industrially manufactured thermal accumulators are a steel tank (usually cylindrical) in the internal cavity of which one or more coils are placed through which the main and additional heating circuits circulate.

Some systems have additional water heating, which is provided by thermal electric heaters located inside. Factory heat accumulators have various devices automation and control of water heating.

Self-copying such devices at home is quite problematic and will not cost much less than the cost in a store. The most complex elements are coils made of stainless or copper tubes, the winding of which is sufficient challenging task when solving it at home.

No less complex are the issues of sealing the outlet fittings to which the heating system is connected and their sealing. Thermal insulation of the battery tank is also a major issue.

Below we will describe the design of a thermal energy accumulator, which is quite suitable for repetition at home. The principle of its operation is as follows:

• the coolant, when the heating boiler is operating at full capacity, is partially directed to the heat accumulator;
• after the boiler is turned off, the heated coolant from the heat accumulator, circulating through, provides heating of living quarters;
• if you place an additional coil inside the device body and connect it to a regular water main, hot water supply to the living space will be provided;
• switching the operation of the heating system when powered from a heating boiler or from a heat accumulator is provided by special shut-off and control valves, which can be activated automatically or switched manually.

Heat accumulator connection diagram

CO – heating system. 1 – automatic coolant distributor;

2 – circulation pump; 3; 4; 5 – shut-off and control valves;

6;7 – temperature sensors.

Calculation of tank volume

Typically, in recommendations for the independent production of heat accumulators for heating private houses, the volume of its tank is taken to be more than 150.0 liters. However, the location and area occupied by the tank depends on this parameter, so it is advisable to determine by calculation method the volume of water required to heat the room, which the thermal energy accumulator tank should accommodate.

The initial data for the calculation are the following data:

Q – specific thermal power required to heat the room in kilowatt-hours;

T – operating time of the heat accumulator per day, hours

t 1 – coolant temperature at the inlet to the heating system, °C;

t 2 – coolant temperature at the outlet of the system, °C;

m – mass of water, kilogram;

с – thermal constant ( specific heat coolant).

The heat balance equation has the form:

Q × T = c× m×(t 1 – t 2 ) (1)

Solving this equation for mass m we obtain the formula:

m = Q× T/[ c× (t 1 – t 2 )] (2)

For heating a private house with a heated area of ​​100.0 square meters it is required to expend 10.0 kilowatts of thermal energy every hour. Let the heat accumulator be assumed to operate with the heating boiler turned off for 5.0 hours at a time. We take the coolant temperature at the inlet – t 1 =80.0°C; at the outlet t 2 =30.0°C. If water circulates in the system, then its specific heat capacity is c = 0.0012 kilowatts divided per kilogram and per degree Celsius. Substituting the initial data into formula 2, you will get the required mass of water:

m = 10.0×5.0/ = 833.33 kilograms

Thus, the capacity of the heat storage device tank must be at least 850.0 liters. Taking into account the thermal inertia of the heating system as a whole and the permissible decrease in coolant temperature, the device will be able to operate in inertial mode for an additional 2.0...3.0 hours.

It should be taken into account that the thermal power of the heating boiler, for the normal functioning of the heat storage system, must exceed that required for heating the room thermal power by 30.0%...50.0%.

To make a heat accumulator, you can purchase a ready-made metal container of a suitable volume. Water tanks designed for watering garden plots are perfect. Some recommend using plastic containers (such as a Eurocube or septic tank).

However, when choosing plastic vessels, even those designed for operating temperatures of up to 80.0C...90.0C, you should be aware that the reliability of the entire system drops sharply, and it is unlikely that any owner will be pleased to find himself without heating in the winter with a cubic meter of water spilled in the room.

The ideal solution would be to make it yourself. At the same time, knowing the volume of the tank and the area of ​​​​the room where it will be located, it is not difficult to independently determine the dimensions. For manufacturing, sheet steel with a thickness of at least 2.0 millimeters is suitable.

In this case, there will be no difficulties with the installation (welding) of the inlet and inlet fittings. If you make a tank in the shape of a parallelepiped or cube, the work on its further thermal insulation will be greatly facilitated.

Insulation of the device body

To increase the energy efficiency of a heat storage device and reduce heat losses through the walls of the housing into the atmosphere, it must be insulated. The ideal heat-insulating material is considered to be sheet foam, the thickness of which is 100.0 millimeters.

In this case, the density of the material must be at least 25.0 kilograms per cubic meter (foam grade “PSB-S 25” and higher). It is easy to process, cut to size, and you can easily cut holes for fittings in it. Attach foam plastic () to the outer walls using glue.

You can also use rolled mineral wool (ISOVER material), with a density of 135.0...145.0 kilograms per cubic meter. However, this material is somewhat more difficult to attach to the walls (especially to the bottom of the tank). However, mineral wool rolls are more optimal for insulating cylindrical containers.

Disadvantages of heat storage devices

The disadvantages of heat accumulators include:

• a significant increase in the volume of coolant, which makes it necessary to use only water;
• the need for a significant reserve volume of water, which makes the choice of designs with additional heating using thermal electric heaters more preferable;
• The capacity and dimensions of the tank without additional electrical heating require a significant area, which is usually solved by installing a mini boiler room.

Main conclusions

The inclusion of a water heat storage device in the heating system allows you to:

• use all the advantages of the “night” tariff when using electric heating boilers;
• save any types of solid fuel;
• increase the energy efficiency of the heating system as a whole.

- This is a special container with liquid that is capable of accumulating coolant energy and releasing it back. Such a device can significantly reduce fuel costs and significantly increase the efficiency (efficiency) of the heating system.

Application of thermal accumulator

A storage container with water is used for houses with periodic heating, namely:

1. For electric boilers equipped with a multi-tariff meter, which operate economically exclusively at night (the cost of electricity at night is 3 times cheaper than during the day).
2. For solid fuel boilers that stop working at night due to the need to periodically add firewood or coal.

The use of such installations in the system not only extends its service life, but also performs a number of other useful functions.

Advantages of a thermal accumulator

The device performs the following functions:

1. It accumulates heat energy, thereby significantly saving fuel.
2. Allows you to connect several heat energy sources in one system (heliometric system, heating element, boiler, etc.).
3. Increases boiler efficiency.
4. Protects all elements from overheating.
5. Heats the water.
6. Controls temperature regime indoors.

Regardless of the advantages of the installation, there are also several disadvantages.

Disadvantages of a thermal battery

The disadvantages include:

1. The amount of water depends on the capacity of the heat storage tank. It acts as a limiter, which is quickly consumed, so you will need additional system for heating.
2. Large tanks require free space to install, in the form of a separate room (boiler room).

Principle of operation

The heat accumulator accumulates energy due to direct or indirect heating in the system, and the temperature reaches its maximum level. As soon as the boiler stops working, the device begins to release the energy accumulated from the heated water back to the coolant.

In order for the heat accumulator to work efficiently, it should be connected as close as possible to the coolant outlet pipe. The design must also meet the following requirements:

1. Correctly selected tank volume, which depends on the heated area.
2. High-quality thermal insulation of the walls, which reduces the level of heat loss.
3. Performing the DHW function (hot water supply).

Heat accumulator – vertical sealed container(tank), which is covered with insulation and has 4 pipes for supplying and discharging water (2 on top and 2 on bottom). The material used for the tank is black or stainless steel, which can be coated with enamel.

Heat accumulator connection diagram

Types of heat accumulators

Classification of storage tanks:

1. Depending on the design of the device there are:
   • Heat accumulators with a built-in coil or heating element.
   • Devices with two or more coils or heating elements.
   • Combined devices where a heating element and a coil are used simultaneously.
2. Depending on the installation location:
   • Thermosiphons - mounted on. They consist of two tanks (internal and external), between which a 50 mm thick heat insulator is installed. The insulator material is polyurethane foam.
   • Buffer containers - similar containers are mounted indoors. The design is the same as that of thermosyphons.
3. Depending on the DHW function:
   • Models with hot water supply.
   • Models without DHW.

The design of the device is very complex, which is why the cost of factory-produced models is so high. To save money, you can build such an installation yourself.

Do it yourself

To develop the installation, you can use steel barrels or ordinary sheets of steel. The shape of the tank can be either cylindrical or square. But before starting production, it is necessary to carry out calculations of volumes, power and thermal insulation.

To find out the volume of the tank, you need to calculate how much liquid should be in the heat accumulator. We use the following formula:

where: Q is the heat energy consumption in the entire system, kW;

c is the heat capacity of water, which is 4.187 kJ/kg ºС or 0.0012 kW/kg ºС;

∆T – Difference between the maximum and minimum values ​​of liquid temperatures in the container and pipeline ºС.

Example! For a room with an area of ​​100 m2, on average, 10 kW of thermal power is required per hour. For 8 hours of inactivity of the heat generator, you will need to accumulate 80 kW. The maximum water temperature is 90ºС, and the minimum is 50ºС. We substitute the data into the formula: m= 80/(0.0012*(90-50))=1667 kg.

It follows from this that the approximate volume of the tank should be 1.7 m 3. Such a tank will provide the heating system with a flow at a temperature of 50ºC for 8 hours. Then the room will gradually cool down and after 3-4 hours the battery will be completely discharged.

Important! In order for the device to have time to fully recharge while the boiler is operating, it needs to have an additional power reserve.

The calculation of the thickness of the thermal insulation directly depends on the power needed to heat the boiler room. The thermal conductivity of insulating materials is 0.040 W/m ºС.

Let's find out how much heat will penetrate into the boiler room, use the formula:

q=S*(Tmax-20)*L/d,(W)

where: S – surface area of ​​the tank without bottom, sq. m.;

Tmax – maximum water temperature, ºС;

20 – indoor air temperature, ºС;

L – thermal conductivity of insulating materials, W/m ºС;

d – heat insulator thickness, m.

Formula for the surface area of ​​a tank without a bottom:

Soс = m/h (sq.m.)

where: Soc – tank base area;

d – circle diameter, mm;

h – tank height, m.

Example! If the height of the tank is 2 m, then Soс = 1.667/2 = 0.834 sq. m. This area will be for a circle with a radius of 1030 mm. Hence S = 0.834+3.14*1.03*2 = 7.30 sq. m.

Using a heat insulator with a thickness of 0.1 m, 204.4 W of heat will flow from the heat accumulator to the boiler room.

q=7.3*(90-20)*0.040/0.1=204.4 W

If this indicator is not suitable, then the insulation thickness must be reduced.

Required materials and tools

To make a heat accumulator, you will need a container with a volume of more than 150 liters. Making such a container yourself is somewhat problematic, but possible. As alternative option you can use Soviet-made tanks, which are made of of stainless steel.

They were previously used by canteens to heat water. And if you couldn’t get hold of such a rarity, any steel container with a wall thickness of 5 mm or more will do. Most affordable option- barrel.

For work you will need the following materials:

1. tank with a capacity of more than 150 liters;
2. thermal insulation material;
3. copper pipes with a diameter of 20-30 mm (coil) or heating elements;
4. thermometer;
5. pipes;
6. fasteners for thermometer and coil (heating element);
7. electric heater with a power of 800 W and a length of approximately 2 m.
8. welding machine;
9. tools.

Several materials can be used as a coolant for the device, the heat capacity of which is presented in the table:

Based on these data, the most accessible and effective material is water.

Manufacturing

Let's take a closer look at how to build a storage tank from a barrel. Device installation steps:

1. Select a barrel the required volume.
2. Clean it, remove dust and debris, get rid of corrosion.
3. Strengthen the barrel with outside stiffening ribs(especially when the heat accumulator is designed for more than 5m3).
4. The bolts need to be welded flange the size of the lid.
5. Increase the thickness of the cover, welding stiffeners to it.
6. Polish inner surface barrels and then treated with phosphoric acid. Then prime the surface 4-6 times and cover with several layers of heat-resistant paint.
7. Weld heating elements or coils inside and make holes for the pipes.

   Important! If opportunities allow, you can use powder coating instead of the standard painting system. The surface should be covered with it after installing the coils. This method allows you to achieve a layer of heat-resistant polymer of equal thickness, which will perfectly protect against corrosive processes.

8. Weld the pipes, check the tightness of the installation, inspect the coil and all seams, holes and the surface of the tank itself.
9. Make an outer cylinder.
10. Sand, prime and treat with silver outside surface of the barrel.
11. Wrap the barrel with aluminum foil and then insulate mineral wool.

There are several safety requirements for homemade installations:

• Contact with hot parts of the installation is prohibited. with flammable and explosive materials.
• Due to the high internal pressure and closed system, maximum tightness must be ensured, install stiffeners and special rubber gaskets for the lid.
• In case of using additional heating in the form of heating elements, it is necessary to insulate all contacts and ground the tank.

Insulation

The following can be used as a heat-insulating material:

1. Polystyrene foam 10 cm thick and density 25 kg/m 3. This material is very convenient to use. It is easy to glue it to metal walls and simply cut holes for the pipes.
2. Mineral wool 10 cm thick and density 135-145 kg/m 3. It is more problematic to attach it to the device.
3. Roll insulation ISOVER. It is used for round tanks made from barrels. It is difficult to attach the material to the barrel, especially in the lower part.

The best option for insulation is a material that does not emit toxic fumes when heated. Foam plastic, unfortunately, does not meet this condition. And mineral wool should not contain phenol-formaldehyde resins. Perfect option for insulation - basalt wool.

Installation and connection

To connect the device, you will first need to select a location for installation. The best option would be to locate it as close as possible to the boiler, then the temperature of the medium will be high and the heating rate of the liquid in the container will increase.

The second stage is the construction of an additional foundation for the installation, since its weight is more than 2 tons. If the system provides hot water supply, you will need to install a water supply system.

Connection diagram homemade device everyone has their own. An approximate connection method for one operating boiler consists of the following steps:

1. Passes through the tank return pipeline , so there should be a 1.5-inch inlet and outlet at its ends.
2. First of all, it is necessary to connect the boiler return to the tank, placing between them. It is required to distribute water from the barrel to expansion tank, shut-off valve and into the heating device.
3. A shut-off valve is also installed on the supply side and a circulation pump.
4. The supply line should be connected in the same way as the return line., but without installing heat pumps.

If the number of circuits is more than two, then the connection diagram will become significantly more complicated.

The heat accumulator should be additionally equipped with a thermometer, an explosion valve and sensors that monitor the pressure level inside. Due to the constant accumulation of heat in the barrel, overheating may occur, so excess pressure should be periodically released.

Making Tips:

1. For storage tanks from scratch, the best option would be to use sheet metal 2 mm thick.
2. The installation can also be welded from stainless steel., but it will cost a little more.
3. To simplify the manufacturing and insulation process, it is better to make a heat accumulator rectangular shape.
4. Do not use plastic barrels for installation, they cannot withstand high temperatures. The exception is barrels marked up to 100 ºС.
5. Must be installed in the lid safety valve , with which to release excess pressure.
6. The factory coil can be replaced with a steel corrugated hose, which will increase the total heat exchange area.
7. To plastic tanks didn't lose their shape they must be enclosed in a lattice frame.
8. Small thermal accumulators can be used for water heated floors as make-up.

Content

If a solid fuel boiler is installed in the house, and we're talking about about the convenience and effectiveness of its use, you should purchase or make a heat accumulator with your own hands. IN Western Europe counts mandatory installation heat accumulator if the house is heated by a boiler running on solid fuel. In our country, the mandatory presence of this unit in the system has not yet been regulated, but homeowners who care about saving have managed to appreciate the advantages of the device.

Thermal accumulator of a solid fuel boiler

Advantages of a thermal accumulator

A traditional Russian stove has two significant advantages over a modern solid fuel boiler:

• if its design is done correctly, fuel combustion in the furnace always occurs at the optimal temperature, due to which the fuel releases maximum thermal energy with the formation of a minimum amount of combustion products;
• The massive brick body of the stove heats up and then releases heat into the room for a long time, that is, it acts as a heat accumulator, allowing you to reduce the number of fireboxes per day.

In order for a solid fuel boiler to function optimally, fully burning fuel, it must operate at its rated power. But when buying a boiler unit for heating a house, the power is chosen based on the coldest days in the region, but these accumulate for no more than two weeks during the winter. Thus, almost all heating season The boiler operates in a limited oxygen supply mode, which reduces its efficiency; fuel is wasted inefficiently, as it releases less heat during combustion.

TA strapping diagram

To avoid this problem, a heat accumulator is connected to the boiler unit - a reservoir of water that accumulates heat during operation of the boiler and supplies heated water to the heating system when the boiler is turned off at night and the temperature of the coolant has dropped.

Note! It is economically profitable to include a thermal accumulator in a heating system with an electric boiler unit if the region has a division into day and night tariffs. In this case, the boiler is turned on only at night to heat the water in the heat accumulator and in the heating system. This allows you to significantly reduce energy costs.

Device operation

Manufacturers produce a heat accumulator for a boiler in the form of a cylindrical water tank into which coils are immersed to circulate the coolant of different heating circuits and the boiler unit.

The water in the tank absorbs excess thermal energy during the operation of the boiler, which heats the coolant and prepares water for the hot water system. Solid fuel boiler (if we are not talking about boilers long burning or an automatic pellet unit) requires quite frequent loading of firewood or coal, so it is stopped at night.

This leads to a gradual cooling of the coolant circulating in the system. Automatic feeding heated water from a heat accumulator to radiators or a heated floor system allows you to maintain heated rooms in the house longer comfortable temperature.

Design features of the heat accumulator

Models offered by manufacturers vary in design and functionality.

Eg, For the sake of convenience and economy, you can heat water in a container in several ways:

• connecting to the boiler for heating;
• installing a heating element in the heat accumulator;
• by connecting the container to the solar collector.

However, the cost of factory-made heat accumulators is quite high, so many homeowners prefer to make a heat accumulator for a solid fuel boiler with their own hands.

When self-made the device is usually not equipped with coils, choosing the simplest option - a container with installed pipes in the upper and lower parts. The supply and return pipes from the boiler are connected to the first pair of pipes, and the supply and return pipes of the heating system are connected to the pair of pipes installed on the opposite side of the tank.

Design and purpose of the capacitive tank

But if there is a desire, time, suitable tools And financial opportunities, you can make a heat accumulator for heating with your own hands by copying a factory-made model or developing your own design. Used for making coils copper pipe, it is also necessary to take care of sealing the places where the ends of the coil are brought out. This approach is primarily in demand when there is a solar collector.

The container requires high-quality thermal insulation, thanks to which the water temperature remains high longer.

Attention! If the heating system does not provide for forced circulation of the coolant, the heat accumulator is installed on a stand made of pipes or an angle to be placed above the level of the radiators - in this case, the heated water can move by gravity. A tube must be installed on the upper horizontal surface of the container to communicate with the atmosphere.

Materials for making containers

Ideally, the tank is made of stainless steel so that the device can function for many years without the risk of corrosion. But the use of such material seriously increases the cost of the design.

A homemade heat accumulator can be made from a metal barrel of suitable volume if the wall thickness is at least 3 mm. The ends of the barrel are sealed with airtight lids.

Homemade heat accumulator

The tank can also be welded from sheet metal with a thickness of 3 mm, in which case it is more convenient to make it rectangular. Moreover, this design simplifies the calculations of the required volume.

You should not use barrels made of polymer materials, since the water in the heat accumulator can heat up to 90 degrees. The exception is polymer containers, the marking of which indicates that the material can withstand heating up to 100 degrees.

A plastic container such as a Eurocube can only be used as a heat accumulator for a heated floor system. The Eurocube material is designed for maximum heating of up to 70 degrees, and coolant heated to 45-50 degrees is supplied to the heated floor circuit.

Thermal accumulator from Eurocube

Insulation

The better the tank is insulated, the less fuel is required to heat the entire volume of water, and the longer the coolant will maintain a high temperature.

You may come across advice to insulate rectangular tanks with sheets of polystyrene foam - it is affordable, is not afraid of moisture and is easy to glue to flat surface heat-resistant composition. However, this is not the best option, since the steel walls of the container become very hot, and polystyrene foam emits when heated. harmful substances.

Reliable option heat accumulator insulation - basalt wool

It is better to perform insulation using rolled material from basalt wool, intended for thermal insulation of chimneys. If you decide to use conventional insulation made of mineral or stone wool, it is necessary to ensure that it does not contain phenol-formaldehyde resins, which also release substances hazardous to health when exposed to high temperatures.

Note! The recommended density of mineral wool thermal insulator is 135-145 kg/m3.

The protective casing is made from sheet metal. It simultaneously protects the heat insulator from moisture and external influences, and serves as a reflector for thermal radiation passing through the insulating layer.

TA installation location

It is worth thinking about installing a heat accumulator at the stage of designing a heating system.

Important! Since the boiler unit will have to heat not only the coolant and water for the hot water system, but also the water in a large-volume tank, the load on the boiler increases significantly. This means that you should purchase a solid fuel boiler, the power of which is approximately 1.5 times higher than the calculated one.

Solid fuel boilers are designed for installation in a specially designated room. When designing a boiler room, you should consider the place where the heat storage device will be installed. It must be freely accessible in order to connect the container to the pipeline.

If it is not possible to place a tank of the required volume in close proximity to the boiler, you can connect two or more small heat accumulators in series.

For a solid fuel boiler, it is necessary to provide a specially designated place - a boiler room

Design calculation

Before preparing drawings and developing diagrams for connecting the heat accumulator to the boiler and pipelines, a number of calculations must be performed.

First of all, it is necessary to calculate the thermal performance of the heating system. But the indicator should be average, and not with a reserve for frosty days, otherwise the volume of the tank will be excessively large and a high-power boiler will be required to heat it.

A rational solution is a full calculation of the heat loss of the house, but here it is more convenient to use the simplified principle, according to which 10 m2 of house area requires 1 kW of heat to warm it up very coldy. The average value will be less than half. Thus, to heat your house of 100 m2, you need a maximum of 10 kW, and on average 5 kW.

It should be assumed that the period of time during which the system should operate when the boiler is not working is 8 hours. That is, if 5 kW is required per hour, then the required supply of thermal energy for 8 hours will be 8 × 5 = 40 kW.

The maximum water temperature in the tank will be 90 degrees, and optimal temperature The coolant in the local radiator system is approximately 60 degrees, so we find the temperature difference, it will be equal to 30 degrees.

• m = Q / c Δt
• Q – thermal energy consumption (we have 40 kW);
• Δt – temperature difference (ours is 30°C);
• с – the value of the specific heat capacity of water equal to 0.0012 kW / kg ºС (4.187 kJ / kg ºС);

We carry out the calculations: m = 40 / 0.0012 x 30 = 1111 kg, that is, if rounded up, the volume of the tank should be about 1.2 m 3. Knowing the required volume and using simple geometric formulas, you can calculate the dimensions of a cylindrical or rectangular tank.

Such a device is capable of maintaining the temperature of the coolant in the radiators at 60 degrees for 8 hours, then the temperature will gradually decrease, but it will take about another 3-4 hours until the rooms completely cool down.

Manufacturing stages

When considering how to make a heat accumulator yourself, you need to pay attention to the requirements for the container - it must be strong enough to withstand operating pressure in the system, this parameter is usually 3 atmospheres.

If a used tank is used as a reservoir metal barrel, you should thoroughly clean its inner surface from traces of corrosion.

Before making a thermal energy storage device, decide how it will be used in the circuit. Typically, a thermal accumulator is installed as a hydraulic separator. In this case, four fittings cut into it. For ease of connection, the length of the fittings should be greater than the thickness of the insulation.

TA with embedded fittings

A pair of fittings are cut into the upper and lower parts on the side of the boiler, the second pair - symmetrically on the opposite side, the heating circuit will be connected to them. Tees with thermometers are connected to the pipes installed in the lower part of the container.

The container with installed fittings should be wrapped in foil, creating a reflective layer. A thermal insulator is attached on top. The rolled material can be secured with wire, tightening the loops by twisting the free ends.

It is advisable to cover the completed thermal insulation layer with a casing, for the manufacture of which thin sheet metal is suitable.

Note! By adding a heating element to the design, you can use electricity to heat the coolant in emergency situations - in case of fuel shortages, boiler breakdown, etc.

Conclusion

Even the simplest heat accumulator for heating boilers can significantly improve a heating system with a solid fuel boiler. Its installation makes it possible to maintain a comfortable temperature level in the house for several hours by extinguishing the fire in the boiler. You have to heat your house less often, which reduces energy costs.

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 operating principle, 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;
• Connect to a heating system built around a solid fuel boiler additional sources heat is extremely difficult. A complex decoupling will be required, preferably with automatic control;
• A solid fuel boiler, even one that burns for a long time, 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 must 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 the 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 out 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 circuit 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.

Upon reaching maximum temperature water in the heater and the target temperature in the radiators, the sensor installed in the boiler is triggered by overheating 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

At great desire 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, with the most top point hot water is being supplied 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

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

Installing a water heat accumulator in the heating system solves many problems at once. WITH solid fuel boilers There are generally many benefits: less heating and more even temperature in the house. This device also helps make heating more economical, since the boiler operates in the most optimal mode - with active burning of wood. A heat accumulator (TA) also makes it possible to heat with electricity at a lower cost. This a good option save for those who have a night rate with a significant difference in price relative to the day rate. The only thing stopping us: high prices for heat storage tanks - hundreds of thousands. There is also a cheaper option - making a heat accumulator with your own hands. It will cost 20-50 thousand - depending on the volume and the chosen material.

Materials, design and insulation

Homemade storage tanks for heating systems are usually made in the form of a cube. Everyone chooses sizes and proportions based on the available area. What is their disadvantage? Most of them are leaky. No, they don't leak and feel very good.

In system closed type, a sealed container is desirable - so that there is no air in the coolant, stable pressure can be maintained. Achieving this in artisanal conditions is not at all easy, although it is possible.

With and without heat exchanger

There are two types of heat accumulators that are installed in heating: with a heat exchanger inside connected to the boiler and without it. In the second case, it is just a container with pipes. Such heat exchangers are installed if the coolant in the system and the boiler is the same, and if the pressure in all parts of the system is the same. The third limitation is temperature. In heating systems of this type, the temperature inside the boiler and at consumers (radiators, heated floors and other devices) can be the same.

At first glance, a heat accumulator without a heat exchanger seems more advantageous: direct heating of water is more efficient than indirect heating (through a heat exchanger). Costs are lower - since the heat exchanger is made of copper pipe or stainless steel and the length of the pipe is several tens of meters.

But, if you run water from the boiler through a coil, the boiler heat exchanger will last longer. After all, a small volume will circulate in this circle. The salts dissolved in it will quickly settle, and since there are no new “arrivals”, there will be no other deposits. Without a coil, all the coolant in the system (including that in the tank) will be pumped, so there will be tens of times more sediment.

What length of pipe should I take for the heat exchanger?

In most cases, heat accumulators are made with heat exchangers. For this purpose, use a copper pipe rolled into a spiral or cast iron radiators. This is all clear. But how long should the pipe be or how many sections in the radiator? This must be taken into account. The exact calculation is long and complex, but approximately it can be calculated as follows:

• According to experimental data, the radiator section has a heat transfer coefficient of about 500 W/sq.m*deg, an inch copper pipe - 800 W/sq.m*deg.
• We also assume that the average temperature difference in the coolant is 10°C.
• To calculate the planned heat reserve, divide it by the heat transfer coefficient of the material (pipe or radiator). We obtain the heat exchange area for this case in square meters.
• We look in the data for the surface area of ​​the material you have chosen (1 meter of pipe or 1 section of radiators). To find the footage or number of sections, divide the resulting heat transfer area by the surface area.

This is a rough estimate. The data will be a little high, but that's not bad. It is much worse if they are underestimated - the coolant in the heat exchanger will boil before the water in the heat exchanger heats up. Therefore, it is better to take it with a reserve.

To make it a little clearer, let’s calculate the length of the pipe and the number of sections if we need to transfer 25 kW of heat to the water in the heat exchanger. 25000 W /800 W/sq.m*grad = 3.21 m2. In the case of an inch tube, about 40 m will be required.

For radiators, the calculation is similar: 25000 W /500 W/sq.m*deg = 5 m2. This is about 20 battery sections.

Which is better - radiators or pipes? From a practicality point of view, radiators are better. If it suddenly turns out that the heat transfer of the heat exchanger made is insufficient, you can always add a couple of sections. It’s more difficult with a pipe - you can’t grow it. You'll either have to take a longer piece, or do something clever with the second circuit of the heat exchanger. There are, however, other options - add fins (to increase the heat transfer area) or install a circulation pump that will create movement in the container. Due to this, heat transfer will increase.

It is easier to install the pump, but it will only work if there is a power supply. So this option is not for all occasions. Unless you have an electric generator or other power source in case of a power outage.

What materials are they made from?

To make a container for storing heat in a heating system yourself:

• Made from ordinary sheet steel 4 mm thick. Most a budget option. The bad thing is that such a tank rusts. But there are technologies and coatings that will prevent/slow down this process (description below).
• Made from stainless steel sheets with a thickness of 2 mm. The problem here is the welds. If welded under normal conditions, in the heating area (seams) the alloying metals burn out, so the seams rust and flow. You can solve the problem by purchasing a TIG torch and cooking in an argon environment.
• From the Eurocube. This is a large plastic container. It does not rust and is sealed. But the temperature of the liquid in it should not exceed 72-73°C, otherwise it will “lead”. In order not to overheat, you will have to increase the volume or reduce the “downtime” between fireboxes.

In general, they make a heat accumulator from large barrels. For a small system, you can weld two or three two-hundred-liter barrels. This container can be placed in small house- up to 60-70 squares.

To prevent a container made of ordinary steel from rusting, the inside must be coated with a sealed compound. For these purposes, a thick film is used to cover the pools. It is welded to the required dimensions locally. There are also rubber-like paints or mastics. Some of them are also used for sealing swimming pools, but many are used in various industries. For both films and mastics/paints, you need to find those whose operating temperature exceeds 100°C (or better yet, 110°C). Another option is heat-resistant glass enamel.

When it comes to heat exchangers, they are made from a variety of materials:

Homemade heat exchangers for heat accumulators are usually made in the form of a spiral. Annealed copper or corrugated stainless steel pipe is excellent for these purposes. Bend them is not a problem, even with a small diameter. These two materials are the leaders. But corrugated pipe not very good in terms of heat transfer. Let her larger area surface, but the movement of coolant along it is difficult. So this is not the best choice. Especially for boilers with low power.

Paired with powerful boilers and in large-volume storage tanks (from a cube or more), cast iron radiators have performed well. This is a budget option, but it has serious drawbacks. The first is great inertia. Until the radiator itself heats up, there is no heat exchange with water. This increases the heating time of the TA. The second drawback is that cast iron rusts. Maybe not so fast, but still. To prevent rust particles from getting into the system, place mud collectors at the outlet of the homemade buffer tank.

Insulation

Since the main task is to retain as much heat as possible, homemade heat accumulators must be insulated. The two most common materials for these purposes are high-density foam (at least 350 g/m³) and mineral wool. It is better to take mineral wool in mats, it is easier to work with. In terms of thickness - take 10 cm for the bottom and sides, the top can be insulated more thoroughly - 15 cm.

To make a self-made heat accumulator look more presentable, and in order to slightly improve heat conservation, you can cover it with foil foam insulation on top of the thermal insulation, sheath it with plywood, OSB or other sheet material.

It’s a little more difficult to insulate the lower part of the buffer tank. Filled with water, it will weigh quite significantly, so many materials will simply crumple, and there will be very little use from them. There are two solutions:

• Use foam/gas as a thermal insulation layer concrete blocks, on top of which lay several layers of basalt cardboard. It turns out to be good thermal insulation.
• Make a tank on legs or weld a frame on which to place the container. In this case, you can use any of the insulation - it can be placed on polyurethane foam.

Unusual materials that have been used to insulate heat accumulators include cellular polycarbonate. It itself retains heat well, as it is used in the construction of greenhouses. It can be laid in several layers, bringing the thermal insulation to almost ideal. In this case, covering with foil thermal insulation makes more sense: the heat will be reflected back to the tank.

Stiffeners or frame

Do-it-yourself heat accumulators are often made from sheet metal. Its thickness is several millimeters. Even with a volume of 500-700 liters, this is a solid capacity. When filled with water, the walls of the container swell to the sides - the water pressure is considerable.

These are the ties inside the heat accumulator - so that the walls are not squeezed out by water

To prevent the walls of the container from bending, you can either weld stiffening ribs from the inside (as in the photo), or weld a frame from corners and metal strips, and then weld it with metal. When choosing an option with stiffeners, they must be welded according long side(if there is one) with a distance of no more than 50 cm. Having welded the transverse strips on opposite sides of the cube, they are connected using metal strips or pins, welding them also with a not too large step.

Examples of homemade heat storage tanks for heating

TA for cheap heating with electricity

This heat storage tank was made for an electric boiler. With its help, heat is stored during the night tariff. The capacity turned out to be large, in order to speed up the process and have a certain power reserve in case the validity period of the night tariff was reduced, three more heating elements of 2 kW each were installed. They are connected as a star to a three-phase network.

Based on materials:

• tank size - 1.5 * 1.5 * 0.75 m (capacity about 1.7 m³), ​​sheet thickness - 4 mm (part of the sheet 1.5 * 6 m went);
• cast iron radiator - 7 sections;
• metal corner - welded around the perimeter of the upper part to fix the lid;
• rubber compressor on a self-adhesive basis - to seal the same lid;
• metal fittings - fittings with external thread, shut-off valves;
• electrodes for welding.

The process of assembling the container itself is simple - you need to:

• Boil all seams, clean, coat with primer.
• Make holes for the pipes, install and weld the fittings.
• Weld the “ties” inside the tank.”

  
  The heating elements are installed at the bottom - heat the coldest layer
  So that the walls do not “swell”
  

• Drill the corners in increments of 15-20 cm. These are holes for the tie screws. then - a harness from the corner.
• Clean weld areas (all), prime, paint.
• Prime and paint all surfaces inside and out.
• Clean, coat with primer twice and paint the cast iron battery/heat exchanger.
• Connect the battery to the terminals made for the heat exchanger and secure it in the tank.
• Glue a rubber seal around the perimeter of the tank lid. It is better to glue it as a whole piece - it will be more airtight.

The finished tank is installed on a layer of high-density polystyrene foam (10 cm), lined on the sides and top with a mineral wool mat 10 cm thick. The insulation is glued to the walls. During operation, the tank and components began to rust heavily. A magnesium anode installed inside helped slow down the process.

Homemade sealed stainless steel tank

Into a heating system with a coal boiler with a capacity of 56 kW (heated area 190 m²), assembled a heat accumulator with a volume of 4 cubic meters. Both the power of the boiler and the dimensions of the tank are taken with a very large margin - the owner wants to heat in cold weather no more than once a day, with a slight minus - once every two or three days. With such parameters he succeeds. It is supposed to supply coolant to the system with a temperature of no higher than 50°C, so the radiators in the rooms are installed with a double reserve (). Each radiator is installed so that it is possible to regulate the temperature in each room separately. For a homemade heat accumulator, stainless steel sheet 2 mm thick was used.

Design features: homemade heat exchanger. It is also made of sheet metal. It consists of two plates, between which strips of metal are welded. These strips are guides for the flow of coolant. They do not reach one of the edges a little, they are located so that the flow goes like a “snake”.

This is how “guides” are welded for the flow of coolant from the boiler

The size of the heat exchanger turned out to be large. To prevent the structure from moving, the lid, in addition to being scalded, was tightened over the area with pins, and the installation sites were scalded with plates made of the same stainless steel. To check the tightness, a pressure test of 3.5 atm was carried out. Everything is intact, there are no leaks.

There are unlikely to be any questions regarding the welding of the body itself. The only thing that might be interesting is that we welded with a regular welding inverter, but with a TIG torch (purchased at a specialized store). An argon tank was also purchased, so the stainless steel was cooked in an argon environment.

A corner was welded along the upper edge, and studs were welded to the corner. A cover with a rubber seal will be installed on them.

Since the container is large, even dense foam plastic will not support it. Therefore, a stand from a steel corner was welded under it.

All this is installed in the boiler room. The tank was covered on all sides with 15 cm thick mineral wool, OSB was sheathed on top of the insulation and painted. IN finished form everything looks good.

Based on the results of operation. In frosts of -25°C, you have to heat it once a day. At a temperature of -7°C or -10°C - once every two days. When it’s even warmer, it’s even less common.

How to make a buffer tank from a Eurocube

If you decide to make a heat accumulator from plastic container, be sure to pay attention to the temperature characteristics. Since the temperature of the coolant can reach 90°C, this should be the temperature that the plastic can withstand for a long time. There are few such Eurocubes and they are expensive. In principle, you can navigate by price. If the container is expensive, this may be suitable. Polyethylene products are characterized by high heat resistance low pressure(PE-HD). These containers are suitable for making a heat accumulator with your own hands.

It is easier to make a heat accumulator from a Eurotank than from any other material. The container is ready, you just need to run the heat exchangers inside, cut through and insert functional devices and fittings. the main task— carefully cut the holes exactly for the fittings. They are sealed using high-temperature sealants (non-acidic).

If you need to install heating elements in a heat accumulator tank made from a Eurocube, it is better to cut out part of the wall and cut out a plate from thick sheet aluminum. Attach the plate to the wall with bolts with paronite gaskets, carefully covering everything with the same sealant.

Insulation:

• sides - foil insulation 5 mm. foil inside + 50 mm. EPPS
• top - 2 layers 10 mm. foil insulation + 50 mm EPS
• bottom is only 10 mm. folgoizol - the cube was placed on it during installation.
• The seams are additionally foamed. So the EPS is safe.

Feedback from use:

“Yesterday it warmed up to +2, so in the morning, at 7-00, it was 85 degrees, in the TA, at 16-00, 78 degrees, around 23-00, before turning on the heating elements - 75. As a result, the heating elements worked very little! But this is not always the case; sometimes it cools down more. Weather, wind, etc. all have an impact.”