Heat accumulator for heating electric boilers. Heat accumulators for autonomous heating systems. Where is the heat accumulator used and how is it arranged

Internal organization and the principle of operation of the heat accumulator for heating boilers is designed to ensure that the required temperature of the coolant is maintained for 5-10 hours after the main energy source is turned off. The storage tank is placed in a harness with solid fuel and electric boilers. Can be connected to a heat pump and solar collectors.

What is buffer capacity

A correctly used principle of operation of a buffer tank in a heating system reduces heating costs and makes heating a building more comfortable. To make sure that it is expedient to connect a tank, it is necessary to consider its structure and principle of operation, as well as take into account the existing advantages and disadvantages.

Device and principle of operation

• Tank - made of sheet metal (with enamel coating), stainless steel. Branch pipes depart from the tank for connection to the heating system and the heat generator. The material of the tank largely determines the service life of the heat accumulator.
• Spiral heat exchanger- installed in models connected to heating systems with several types of heat carriers (heat pump, solar collectors). Made from stainless steel.
• Built-in DHW coil- some buffer tanks, in addition to maintaining the heating temperature of the coolant in the heating system, heat water for hot water supply.

In the case there is an inspection window for servicing the tank, removing scale and debris, carrying out repair work if necessary.

Purpose of heat accumulators

The purpose of installing a storage tank varies depending on the type of heat source:

The tasks and purposes of using heat accumulators are different. In some cases, the installation of a tank is an indispensable condition for operation, in others it is only a desired requirement that ensures comfortable and economical heating of the building.

Pros and cons of buffer capacity

Now about the benefits of connecting. There are several of them:

• Possibility of uninterrupted operation of solid fuel boilers- if a buffer tank is not installed in the heating system, the coolant begins to cool immediately after the firewood burns out. A drop in temperature is felt by a person after about 3 hours.
  Cooling down will be slower when a heat accumulator is connected. The water in the heating system will remain hot for about 5-10 hours (depending on the volume of the heat accumulator).
• Profitability - excess thermal energy is accumulated and used when the coolant cools down, which significantly reduces fuel costs.
• Safety - the operation of boilers with cast-iron heat exchangers is facilitated. After the tank, the water enters the boiler warm, which eliminates damage to the core from rapid cooling.
• Additional functions- in the device of some tanks there is a DHW coil. There is a simultaneous accumulation of the heated coolant and heating of hot water. The installation can satisfy the needs for hot water supply of residents of the house using single-circuit solid fuel or electric boilers not designed to provide hot water.

Which heat accumulator to choose

When choosing, pay attention to several technical characteristics:

• Storage tank material- a stainless steel tank is unreasonably expensive, especially considering that the battery receives a coolant from the heating system, which is less aggressive than water in the hot water supply. Enamelled finish using glass polymers, the optimal solution.
• Additional functions- it is possible to select a tank for various water consumers, connect heating systems using water as a coolant and special compositions (heat pump, solar collectors). Special mention should be made of tanks capable of heating water simultaneously with the accumulation of thermal energy.

How to calculate buffer capacity

• heated area;
• boiler power;
• time of autonomous maintenance of temperature in the heating system after the boiler is turned off.

To obtain exact value use the second method, according to the formulas for calculating the buffer capacity. During the calculations, several values ​​​​are calculated:

• accumulator accumulation time or water heating up to the temperature of 80-90°С;
• battery life;
• boiler power.

• Q = m×cp×(T2-T1)- according to the calculations, it will be possible to calculate how long it will take to accumulate sufficient thermal energy and find out possible losses. Values:
  • m - coolant flow rate;
  • wed - specific heat;
  • T2 and T1 - initial and final temperature of water heating in the tank.
  Using the formula, a heat accumulator is calculated for a solid fuel or electric boiler.
• Calculations for solar collectors are carried out somewhat differently. The formula Va=Sl × (Vn/Sn) is used. In order not to go into technical details in the calculations, you can use the following table:

And lastly, the capacity of the buffer tanks is chosen so that 30-50 liters of coolant account for 1 kW of boiler energy.

For convenience in the calculations, you can use the following table:

The determination of the minimum amount of heat produced in kW is carried out using the tables attached below.

Calculations for electric boilers, subject to the use of the night tariff:

The minimum required power to maintain the buffer tank connected to the solid fuel boiler in working condition:

Which company to buy a buffer drive

To facilitate the choice of buffer capacity, the following is a description of the most popular models for domestic consumers:

From the presented list of heat accumulators, you can choose equipment suitable for housing of any size, heated by an electric or solid fuel boiler, heat pump, with and without the possibility of heating hot water.

Immediately after connecting the buffer tank, fuel costs will decrease by 15-30%. More importantly, the boiler will no longer be subjected to hydraulic shocks, and the heating of the coolant in the heating system will become more uniform. The battery tank occupies an integral place in modern systems heating.

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

With a solid fuel boiler, this is difficult to implement, because it is not always possible to fill a new portion of firewood or coal on time, and the combustion process itself is uneven. A heat accumulator for heating boilers will help to correct the situation.

With a simple design and principle of operation, it is able to get rid of a number of inconveniences and shortcomings of the classical heating scheme.

Why do you need

The heat accumulator is a well-insulated large-capacity tank filled with a coolant, water. Due to the high heat capacity of water, when the entire volume is heated, a significant supply of thermal power is accumulated in the tank, which can be used for its intended purpose at a time when the boiler cannot cope or is completely inactive.

The heat accumulator actually increases the volume of the coolant in the heating circuit, the heat capacity and, accordingly, the inertia of the entire system. It will take more energy and time to heat the entire volume with a limited heating power, but it will also take a very long time to cool the battery. If necessary, hot water from the accumulator can be supplied to the heating circuit and maintain a comfortable temperature in the house.

To appreciate the benefits of a heat storage, it is easiest to consider a few situations to begin with:

• A solid fuel boiler only periodically heats the water. At the moment of ignition, the power is minimal, during active combustion, the power increases to a maximum, after the bookmark burns out, it decreases again and so the cycle repeats. As a result, the water temperature in the circuit constantly fluctuates in a fairly large range;
• To obtain hot water, an additional heat exchanger or an external boiler with indirect heating, which significantly affects the operation of the heating circuit;
• It is extremely difficult to connect additional heat sources to a heating system built around a solid fuel boiler. A complex interchange will be required, preferably with automatic control;
• Solid fuel boiler, even long burning constantly requires user attention. It is worth skipping the time for laying a new portion of fuel, as the coolant in the heating circuit is already starting to cool down, like the whole house;
• Often the maximum power of the boiler is excessive, especially in spring and summer, when maximum output is not required.

The solution for all of the above situations is a heat accumulator, moreover, uncompromising and the most affordable in terms of implementation and cost. It acts as a decoupling point between the solid fuel boiler and the heating circuit(s) and an excellent base platform for enabling additional functions.

By design, the heat accumulator can be:

• "empty" - a simple insulated container with a direct connection;
• with a coil or register of pipes as a heat exchanger;
• with built-in boiler tank.

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

Payment

The power accumulated by a heat accumulator (TA) is calculated based on the volume of the container, more precisely, the mass of the liquid in it, the specific heat of the liquid used to fill it, and the temperature difference, the maximum to which the liquid can be heated, and the minimum target, at which it can still be carried out. heat intake from the heat accumulator to the heating circuit.

• Q \u003d m * C * (T2-T1);
• m is the mass, kg;
• С – specific heat capacity W/kg*K;
• (T2-T1) - temperature delta, final and initial.

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

The stored energy should be enough 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 TA should be enough to cover the heat loss of the house;
• The time during which the coolant in the heat exchanger should be heated;
• The power of the main heat source.

For periodic operation of the boiler during the day

If it is needed to transfer the operation of the boiler only to night or day mode, when heat is supplied for a limited time, then the power of the TA should be enough to cover the heat loss of the house for the remaining time. At the same time, the power of the boiler should be enough to heat the TA within the prescribed period and, again, to heat the house.

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. It takes 120 kWh per day for full heating.

In this case, the battery is used for 14 hours, which means that it is necessary to accumulate 5 kW * 14 hours = 70 kW * hours of heat in it. If we take water as a heat carrier, then 1.75 tons or a TA volume of 1.75 m3 will be required. It is important that the boiler must also give out all the necessary heat within just 10 hours, that is, its power must be more than 120/10 \u003d 12 kW.

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

But in this case, it is not necessary for the TA to heat up in a short period of time. A one and a half margin of boiler power is enough to accumulate the required amount of heat in a week or two.

The calculation is approximate, without taking into account the decrease in the heat output of radiators depending on the temperature of the coolant and the 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 HT and the boiler, so that hot water enters the upper part of the HT, pushing cold water from the lower part into the boiler. Between the TA and the heating circuit, a circulation pump is installed to draw hot water from the upper part and transport it to the radiators.

However, this significantly increases the total heat capacity of the system, and at the initial start of heating, you will have to wait until the entire volume of the HA is heated before the heat reaches the radiators.

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

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

Of the advantages, only ease of connection and a minimum of elements used.

Switching circuit with mixing

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

The main part of the automation is installed on the supply pipeline: a three-way valve, thermostats, a safety group, etc. By default, a 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 TA and the target temperature in the radiators are reached, the overheating sensor installed in the boiler is activated and it turns off. While heating is required or the heat accumulator is not warmed up, the operation of the boiler continues.

If, for some reason, the boiler stopped producing rated power or turned off completely when the temperature on the supply line dropped, 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 distribution and on the return 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.

DIY

With a strong desire, you can build a storage tank with your own hands. Ideally, she should:

• with a margin to withstand the nominal pressure in the system;
• have an estimated volume;
• be protected from corrosion and high temperatures;
• be completely sealed.

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

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

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

It is almost impossible to weld a cylindrical container on your own. It is easier to build a box 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 a heat accumulator, prepare a special support platform, foundation, capable of withstanding the enormous weight of the equipment. Even the battery itself can weigh up to 400-500 kg. If its volume, for example, is 3 cubic meters, then when filled, its weight will exceed 3.5 tons.

Russian production

On Russian market there are not so many heat accumulators of domestic production, since only recently they began to be actively introduced into autonomous heating systems.

Heat accumulator for heating boilers

We continue our series of articles with a topic that will be of interest to those who heat their homes with solid fuel boilers. We will talk about the heat accumulator for heating boilers (TA) on solid fuels. This is a really necessary device that allows you to balance the operation of the circuit, smooth out the temperature drops of the coolant, while also saving money. We note right away that a heat accumulator for electric heating boilers is used only if the house has an electric meter with separate calculation of night and day energy. Otherwise, installing a heat accumulator for gas heating boilers does not make any sense.

How does a heating system with a heat accumulator work?

A heat accumulator for heating boilers is a part of the heating system designed to increase the time between loading solid fuel into the boiler. It is a reservoir in which there is no air access. It is insulated and has a fairly large volume. There is always water in the heat accumulator for heating, it also circulates throughout the circuit. Of course, an antifreeze liquid can also be used as a coolant, but still, due to its high cost, it is not used in circuits with TA.

In addition, there is no point in filling the heating system with a heat accumulator with antifreeze, since such tanks are placed in residential premises. And the essence of their application is to ensure that the temperature in the circuit is always stable, and, accordingly, the water in the system is warm. The use of a large heat accumulator for heating in country houses of temporary residence is impractical, and there is little sense from a small reservoir. This is due to the principle of operation of the heat accumulator for the heating system.

• The TA is located between the boiler and the heating system. When the boiler heats up the coolant, it enters the TA;
• then the water flows through the pipes to the radiators;
• The return line returns to the TA, and then immediately to the boiler.

Although the heat accumulator for the heating system is a single vessel, due to its large sizes the direction of flow at the top and bottom is different.

In order for TA to perform its primary function of heat storage, these streams must be mixed. The difficulty lies in the fact that the heat always rises, and the cold tends to fall. It is necessary to create conditions so that part of the heat sinks to the bottom of the heat accumulator in the heating system and heats the return coolant. If the temperature has evened out in the entire tank, then it is considered fully charged.

After the boiler fired everything that was loaded into it, it stops working and TA comes into play. The circulation continues and it gradually releases its heat through the radiators into the room. All this happens until the next portion of fuel enters the boiler again.

If the heat storage for heating is small, then its reserve will last for a very short time, while the heating time of the batteries increases, since the volume of the coolant in the circuit has become larger. Cons of using for temporary residences:

• the warm-up time increases;
• a larger volume of the circuit, which makes filling it with antifreeze more expensive;
• more high costs for installation.

As you understand, filling the system and draining water every time you arrive at your dacha is at least troublesome. Considering that the tank alone will be 300 liters. For the sake of several days a week, it is pointless to take such measures.

Additional circuits are built into the tank - these are metal spiral pipes. The liquid in the spiral does not have direct contact with the coolant in the heat accumulator for heating the house. These can be contours:

• low-temperature heating (warm floor).

Thus, even the most primitive single-circuit boiler or even a stove can become a universal heater. It will provide the whole house with the necessary heat and hot water simultaneously. Accordingly, the performance of the heater will be fully utilized.

In serial models manufactured under production conditions, additional heating sources are built in. These are also spirals, only they are called electric heating elements. There are often several of them and they can work from different sources:

• electricity grid;
• solar panels.

This heating is additional options and is not mandatory, consider this if you decide to make a heat accumulator for heating with your own hands.

Heat accumulator piping schemes

We dare to assume that if you are interested in this article, then most likely you decided to make a heat accumulator for heating and tie it yourself. You can come up with a lot of connection schemes, the main thing is that everything works. If you correctly understand the processes occurring in the circuit, then you can quite experiment. How you connect the HA to the boiler will affect the operation of the entire system. Let's first analyze the simplest heating scheme with a heat accumulator.

simple circuit strapping TA

In the figure you see the direction of movement of the coolant. Please note that upward movement is prohibited. To prevent this from happening, the pump between the TA and the boiler must pump a larger amount of coolant than the one that stands up to the tank. Only in this case will a sufficient retracting force be formed, which will take part of the heat from the supply. The disadvantage of such a connection scheme is the long heating time of the circuit. To reduce it, you need to create a boiler heating ring. You can see it in the following diagram.

TA piping scheme with a boiler heating circuit

The essence of the heating circuit is that the thermostat does not mix water from the TA until the boiler warms it up to the set level. When the boiler is warmed up, part of the supply goes to the TA, and the part is mixed with the coolant from the reservoir and enters the boiler. Thus, the heater always works with an already heated liquid, which increases its efficiency and the heating time of the circuit. That is, the batteries will get warm faster.

This method of installing a heat accumulator in a heating system allows you to use the circuit offline when the pump is not running. Please note that the diagram shows only the nodes for connecting the TA to the boiler. The circulation of the coolant to the radiators occurs in a different way, which also passes through the TA. The presence of two bypasses allows you to play it safe twice:

• the check valve is activated if the pump is stopped and the ball valve on the lower bypass is closed;
• in the event of a pump stop and breakdown check valve circulation is carried out through the lower bypass.

In principle, some simplifications can be made in such a construction. Given the fact that the check valve has a high flow resistance, it can be excluded from the circuit.

TA piping scheme without check valve for gravity system

In this case, when the light disappears, you will need to manually open the ball valve. It should be said that with such a wiring, the TA should be above the level of the radiators. If you do not plan that the system will work by gravity, then the piping of the heating system with a heat accumulator can be performed according to the scheme shown below.

Scheme of piping TA for a circuit with forced circulation

In TA, the correct movement of water is created, which allows ball after ball, starting from the top, to warm it up. Perhaps the question arises, what to do if there is no light? We talked about this in an article about alternative power sources for the heating system. It will be more economical and more convenient. After all, gravity circuits are made of large-section pipes, and besides, not always convenient slopes must be observed. If you calculate the price of pipes and fittings, weigh all the inconveniences of installation and compare it all with the price of a UPS, then the idea of ​​\u200b\u200binstallation alternative source nutrition will become very attractive.

Calculation of the volume of the heat storage

The volume of the heat accumulator for heating

As we have already mentioned, it is not advisable to use a small volume TA, while too large tanks are also not always appropriate. So the question arose of how to calculate the required volume of TA. I really want to give a specific answer, but, unfortunately, it cannot be. Although there is still an approximate calculation of a heat accumulator for heating. Let's say you don't know what heat loss your house is and you can't find out, for example, if it hasn't been built yet. By the way, to reduce heat loss, you need to insulate the walls of a private house under the siding. You can choose a tank based on two values:

• the area of ​​the heated room;
• boiler power.

Methods for calculating the volume of TA: room area x 4 or boiler power x 25.

It is these two characteristics that are decisive. Different sources offer their own calculation method, but in fact these two methods are closely related. Suppose we decide to calculate the volume of a heat accumulator for heating, starting from the area of ​​\u200b\u200bthe room. To do this, you need to multiply the quadrature of the heated room by four. For example, if we have little house 100 square meters, you will need a tank of 400 liters. This volume will reduce the loading of the boiler up to two times a day.

Undoubtedly, there are pyrolysis boilers that are loaded with fuel twice a day, only in this case the principle of operation is slightly different:

• fuel ignites;
• the air supply is reduced;
• the smoldering process begins.

In this case, when the fuel flares up, the temperature in the circuit begins to rise rapidly, and then smoldering keeps the water warm. During this very smoldering, a lot of energy escapes into the pipe. In addition, if a solid fuel boiler works in tandem with a leaky heating system, then at peak temperatures the expansion tank sometimes boils. In the truest sense of the word, water begins to boil in it. If the pipes are made of polymers, then this is simply fatal for them.

In one of the articles about polymer pipes we talked about their characteristics. TA takes away some of the heat and the tank can boil only after the tank is fully charged. That is, the possibility of boiling, with the right amount of TA, tends to zero.

Now let's try to calculate the volume of TA, based on the number of kilowatts in the heater. By the way, this indicator is calculated on the basis of the quadrature of the room. 1 kW is taken for 10 m. It turns out that in a house of 100 square meters there should be a boiler of at least 10 kilowatts. Since the calculation is always done with a margin, we can assume that in our case there will be a 15 kilowatt unit.

If you do not take into account the amount of coolant in the radiators and pipes, then one kilowatt of the boiler can heat approximately 25 liters of water in the TA. Therefore, the calculation will be appropriate: you need to multiply the boiler power by 25. As a result, we will get 375 liters. If we compare with the previous calculation, the results are very close. Only this is taking into account that the boiler power will be calculated with a gap of at least 50%.

Remember, the more TA, the better. But in this case, as in any other, one must do without fanaticism. If you put a TA for two thousand liters, then the heater simply cannot cope with such a volume. Be objective.

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Heat accumulator in the heating system

The heating system includes, in the usual view that has developed over the years, three elements - a heat source (boiler), pipelines and directly heating appliances(radiators). But if this private house with a solid fuel boiler (wood, peat briquette, coal) and you want to increase efficiency and save yourself from the need to constantly monitor the furnace, then it may be worth using such a unit as a heat accumulator in the system. [content]

The principle of operation of the heat accumulator

The main task performed by the heat accumulator is to increase the inertia of the heating system. To do this, increase the volume of the coolant and, consequently, the amount of heat accumulated by it. Thus, the battery is an insulated container embedded in the heating circuit.

As mentioned above, the battery significantly increases the inertia of the system, that is, although the coolant heats up longer, it accumulates more heat and gives it longer and reduces temperature fluctuations.

The internal structure of the heat accumulator

Thus, if the house is connected to central heating or the system uses gas or liquid fuel boilers operating in automatic mode, heat accumulators are simple extra costs material and funds. But there are cases when their use is more than justified:

1. If solid fuel boilers are used in the heating system (especially without bunker loading), and there is no way to ensure their constant maintenance (in a private house). In this case, the heat accumulator will provide a constant stable temperature in the room, and even be able to smooth out the inevitable surges during cleaning and ash removal;
2. If electrical water heating and a differentiated system of payment for electricity is applied. Heat accumulators will make it possible to accumulate heat during hours when the tariff is minimal, and in the future, heaters can be used at minimum power;
3. If the heating system has periods of peak analysis of thermal energy (most often this is due to the cost of heating water, for example, with intensive operation of showers), and installing an additional boiler is not practical. The battery will be able to provide heat transfer during these usually short periods of time.

Where the heat accumulator will be "superfluous"

Sometimes for heating systems, on the contrary, it is desirable to quickly set the temperature and decrease it, in this case, the increased amount of coolant accumulated by the storage tanks will only interfere with rapid heating and cooling and precise temperature control. In particular:

1. If heating is needed only for short periods of time and excessive fuel consumption is undesirable. For example, a boiler house is used to heat a dryer, which is used only occasionally. In this case, it does not make sense to heat the empty room from which the material is unloaded with the accumulated heat.
2. If, in addition to heating, a heat plant is also used to provide heat for some technological equipment and a quick and accurate change in temperature regimes is required, increased inertia will only interfere.

How heat accumulators crash correctly

If a forced circulation heating system is used, then the tie-in point does not play special significance, since the pump delivers thermal energy from the accumulator. You can choose any comfortable spot given that the battery has a decent size.

For its correct operation, it is necessary to correctly position the connecting pipes - the inlet (according to the movement of the thermal energy carrier in the system) at the bottom, the outlet at the top.

Heat accumulator connection diagram

If heating is used natural circulation, then the location of the tie-in plays an important role. Many people make the mistake of combining heat accumulators and expansion tanks. Expansion tank is located at the highest point of heating and hot water from it can begin to move, only cooling down through the pipes and increasing its density. For efficient operation, the heat accumulator must be located at the bottom of the heating supply pipe and as close as possible to the boiler.

Is it possible to assemble and install a thermal energy accumulator on my own?

From a constructive point of view, thermal energy accumulators are quite simple - this is a container with heat-insulated walls, equipped with nozzles for connecting to the heating system. Therefore, it will not be difficult for any person who has the skills of plumbing and welding to assemble or adapt containers for batteries.

The question of calculating the thermal insulation of the walls may only arise. But in this case, the principle “more is better than less” can be applied, since for tanks used as heat accumulators, due to their shape, there is no concept of effective thermal insulation radius.

The video below shows the installation diagram and the principle of operation of the heat accumulator:

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A heat accumulator for a heating system - the main advantages. Press!

The desire of many owners of private houses and cottages to use resources as efficiently as possible to heat their homes quite often faces the same problem - even when using all modern technologies insulation and energy saving, installation of the most economical heating boilers - there is no significant saving of resources.

In many ways, this is a consequence of mistakes made long before the question of prudent use of resources and the use of modern construction technologies was raised. But what about the new houses built according to all modern canons, has the limit of development really come?

For most, this will remain a rhetorical question, but for those who decide to use really scientific knowledge, and not excerpts from advertising booklets, it is worth thinking about including a new element in the heating system - a heat accumulator.

How the heating system works

In the modern understanding of the energy efficiency of heating installations, including a separate house or cottage, in recent times the emphasis has shifted significantly from the fuel consumption indicator for space heating to the indicator that characterizes the efficiency of energy use for the complete heat supply of the house.

Such a justified focus on energy efficiency allows us to take a fresh look at the problem of home heat supply, which includes two main tasks:

• House heating;
• hot water supply.

A new way to save energy in the heating system of a building today is the installation in the heating system additional equipment, whose function is to accumulate thermal energy and gradually consume it.

The use of a heat accumulator in the scheme of heating system devices, where the solid fuel boiler acts as the main source of energy, makes it possible to reduce fuel consumption by up to 50% without additional costs. heating season. But this is in the future, but for now it is quite clear to consider the principle of operation of this device.

The principle of operation of the system with a solid fuel boiler

The highest effect from connecting to the system will be in relation to solid fuel boilers.

The heat released during the combustion of fuel through the heat exchanger through the pipeline enters the registers or radiators, which are essentially the same heat exchangers, only they do not receive heat, but, on the contrary, give it to surrounding objects, air, in general, to the heating room.

Cooling down, the coolant - water in the batteries, goes down and again flows into the boiler heat exchanger circuit, where it heats up again. In such a scheme, there are at least two points associated with a large, if not a huge loss of heat:

• direct direction of movement of the coolant from the boiler to the registers and rapid cooling of the coolant;
• a small volume of coolant inside the heating system, which does not allow maintaining a stable temperature;
• the need to constantly maintain a consistently high temperature of the coolant in the boiler circuit.

It is important to understand that such an approach can only be called wasteful. After all, when laying fuel, first at a high combustion temperature in the premises, the air warms up quite quickly. But, as soon as the combustion process stops, the heating of the room will also end, and as a result, the temperature of the coolant will drop again, and the air in the room will cool.

Using a thermal storage

Unlike a standard heating system, a system equipped with a heat accumulator works a little differently. In its most primitive form, immediately after the boiler, the tank is installed as a buffer device.

A tank with multilayer thermal insulation is installed between the boiler and pipelines. The capacity of the tank, and it is calculated in such a way that the amount of coolant inside the tank is greater than in the heating system, contains the coolant heated from the boiler.

Several heat exchangers are introduced inside the tank for the heating system and for the hot water supply system. The internal volume of the accumulator heated from the boiler can maintain a high temperature for a long time and gradually release it for heating and water supply systems.

Given that the smallest tank has a volume of 350 liters of water, it is easy to calculate that by spending the same amount of fuel when using a heat accumulator, the effect will be much greater than with a direct heating system.

But this is the most primitive kind thermal device. A standard, designed to really work in the conditions of heat supply of a separate house, a heat accumulator can have:

The price of such batteries depends on many factors:

• tank material;
• the volume of the internal tank;
• the material from which the heat exchanger is made;
• manufacturer's firms;
• a set of additional equipment;

Specialist note: calculate correct work of the entire heating system, starting from the TT boiler and ending with the diameter of the steamers, in principle, you can do it yourself, but it should be borne in mind that the power of both the boiler and the installation itself must be designed to work in conditions of maximum low temperatures in the region.

More detailed information on this issue today can be found on the pages of Internet sites, both in text form and using the services of specialized online calculators, and of course in specialized companies involved in the development and installation of heat supply systems.

Everything is electronically controlled

Perhaps, for many, such a concept as a “smart home” has long been included in the usual rhythm of life.

A house in which electronics takes over many functions for the maintenance and management of systems cannot do without the participation of electronic components and the operation of the heating and water supply system with a heat accumulator.

To maintain a stable comfortable temperature, it is necessary not so much to constantly burn fuel in the boiler furnace, but to maintain a stable temperature in the heating system. And with such a task, the electronic control of the operation of the heat accumulator is quite coping.

Control board features:

In addition, the electronic component can be perfectly used as a controller for the operation of both a solid fuel boiler and electric heaters, and even as a use of the system. solar collector for maximum benefit and resource savings.

The economic effect of even including a heat accumulator in the heat supply scheme allows, as already mentioned, to reduce fuel costs in the heating season by up to 50%, and given that the price of energy carriers is constantly growing, such an investment becomes not only profitable, but already mandatory for new buildings.

Watch the video in which the user explains in great detail the scheme of the solid fuel boiler, coupled with a heat accumulator:

heat.guru

Heat accumulator in the heating system: familiarity with the principle of operation, design and installation options

Why are heat accumulators needed in heating systems? How are they arranged? How to include a heat accumulator in a common circuit when installing a heating system with your own hands? Let's try to figure it out.

The hero of our article is in the photo on the right.

First meeting

What is a storage tank for heating?

In the simplest version - a tall cylindrical or square tank with several nozzles on different height from the base. Volume - from 200 to 3000 liters (the most popular models are from 0.3 to 2 cubic meters).

The list of options and options is quite large:

• The number of nozzles can vary from four to a couple of dozen. It all depends on the configuration of the heating system and on the number of independent circuits.
• The thermal accumulator of water heating can be thermally insulated. 5-10 centimeters of foamed polyurethane foam will significantly reduce untargeted heat losses if the tank is located outside the heated room.

Tip: even if the tank is inside the house and, it would seem, its heat transfer helps the radiators to perform their functions, thermal insulation will not hurt. The amount of heat emitted by a tank with a volume of 0.3-2 cubic meters is VERY large. Our plans do not include organizing a round-the-clock sauna.

• The wall material can be either black steel or stainless steel. It is clear that in the second case longer term services of a heat accumulator, but its price is also higher. By the way, in closed system water quickly becomes chemically inert, and the corrosion process of black steel is greatly slowed down.
• The tank can be divided into communicating sections by several horizontal partitions. In this case, the stratification of water by temperature inside its volume will be more pronounced.
• Flanges for mounting tubular electric heaters can be located on the tank. In fact, with sufficient power, the accumulator for heating systems will turn into a full-fledged electric boiler.
• The heat storage tank can be equipped with a heat exchanger for the preparation of hot drinking water. Moreover, it can be a flow-through plate heat exchanger, and a storage tank inside the main tank. Compared to the amount of heat stored in the tank, the cost of heating water will in any case be negligible.
• An additional heat exchanger for connecting the solar collector can be located at the bottom of the tank. It is at the bottom - to ensure efficient heat transfer from the collector to the storage tank, even at low efficiency (for example, at dusk).

So the heat accumulator is used in the solar heating system.

Functions

It is easy to guess that heating heat accumulators are needed in order to accumulate thermal energy in reserve. But even without them, the heating seems to work, and not bad. In what cases is their use justified?

solid fuel boiler

For solid fuel boilers (with or without a water circuit), the most efficient mode of operation is in which the fuel burns with a minimum amount of residues (including not only ash, but also acids and tar) and maximum efficiency - full power. Power adjustment is usually carried out by restricting air access to the furnace - with unambiguous consequences.

However, dispose of all thermal power- means for a short time heat the radiators almost red-hot, and then let them cool. This mode is extremely inefficient, leads to accelerated wear of pipes, their connections and provides uncomfortable temperature regime in home.

This is where a heating system with a heat accumulator comes to the rescue:

• The heat generated by the boiler at full power is utilized to heat the water in the tank.
• After the fuel burns out, the water continues to circulate between the storage tank and the radiators, taking away heat from it GRADUALLY.

As a bonus, we get a much rarer kindling of the boiler, which will save us both strength and time.

The buffer tank will allow the solid fuel boiler to operate optimally.

Electric boiler

What is the advantage of thermal storage heating when electricity is used as a heat source? After all, all modern electric boilers can smoothly or stepwise regulate power and do not need frequent maintenance?

The key phrase is the night rate. The cost of a kilowatt-hour in the presence of a two-tariff meter can be VERY different at night, when the power systems are unloaded, and during the day, at the peak of consumption.

By varying tariffs, power engineers distribute electricity consumption more evenly; well, this is in our favor:

1. At night, the programmable boiler turns on by a timer and heats the accumulator for heating to its maximum operating temperature at 90 degrees.
2. Happy accumulated thermal energy used for home heating. The flow rate of the heat carrier for heating systems is dosed by adjusting the performance of the circulation pump.

A heat accumulator in combination with a two-tariff meter will help to significantly save on heating.

Multi-circuit heating

Another very useful function of the storage tank is the ability to use it simultaneously with the accumulation of energy as a hydraulic gun. What is it and why is it needed?

Recall that there are usually more than four nozzles on the body of a tall tank. Although, it would seem, quite enough entry and exit. At different levels, water with different temperatures can be taken from the storage tank; as a result, we can get, most typically, a high-temperature circuit with radiators and low temperature heating- warm floor.

Please note: pumps with thermal control circuits will still be needed. At different times of the day at the same level of the tank, the water temperature will vary greatly.

Branch pipes can be used not only as outlets for heating circuits. Several boilers different types can also be connected to a heat accumulator.

Connection and thermal capacity

What does a heating system with a heat accumulator look like?

Heat accumulators for heating are connected in the same way as hydraulic arrows and, in general, differ from them only in thermal insulation and volume. They are placed between the supply and return pipelines leading from the boiler. The supply is connected to the top of the tank, the return to the bottom.

The secondary circuits are powered depending on what temperature of the coolant they require: high-temperature heating draws water from the top of the tank, low-temperature heating from the bottom.

Principal connection diagram.

The instruction for calculating the thermal capacity is based on a simple formula: Q = mc(T2-T1), where:

• Q - accumulated heat;
• m is the mass of water in the tank;
• c - specific heat capacity of the coolant in J / (kg * K), for water equal to 4200;
• T2 and T1 - initial and final temperatures of the coolant.

Let's say a heat accumulator with a volume of two cubic meters at a temperature delta of 20C (90-70) and using water as a coolant can accumulate 2000kg (we will take the density of water as 1kg / l, although at 90C it is slightly less) x4200 J / (kg * K) x20 = 168000000 Joules.

What does this amount of energy mean? The tank can deliver 168 megawatts of thermal power in one second or, more realistically, 5 kilowatts in 33,600 seconds (9.3 hours).

Conclusion

As usual, you can learn more about heat accumulators by watching the video attached to the article (see also the water heating scheme for a private house).

Corrugated pipe for heating

When heating a house, it often happens that in daytime during the day there is an opportunity to generate heat in excess, and at night it is not enough. There is also the opposite situation, in which it is more profitable to use heating at night. Such moments will help smooth out the heat accumulator for heating. But you need to know how to choose it correctly, install it and connect it to the system. Detailed information on this topic you can learn from this article.

When you need a heat accumulator

This simple element of the heating system in the form of an insulated water tank is recommended to be installed in such cases:

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

For reference. There are also water heat accumulators for greenhouses, used to store 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 shut off the air to lower the temperature in the furnace, then the efficiency also decreases. The homeowner also has a lot of worries about the frequency of burning, the firewood has burned out - you have to load new ones, it is extremely inconvenient to do this in the middle of the night. The solution is simple: you need a storage tank that accumulates the previously generated heat to use it 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 do not use electricity during the day. And here the heat accumulator in the heating system will allow you to organize the optimal schedule for the operation of the heat source, giving out to the system hot water while the heat generator is idle.

Important. For joint work with a heat accumulator, the boiler must have at least one and a half reserves in terms of thermal power. Otherwise, he 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, in the daytime they are even ventilated. In order to accumulate solar energy for use at night, you can use the simplest heat accumulator of Lezhebok to heat the ground. This is a black polymer sleeve filled with water and laid directly on the bed, it does not allow the soil to cool down at night. To absorb more heat, barrels of water, painted black, are placed inside the greenhouse.

Heat accumulator calculation

A container for the accumulation of thermal energy can be either purchased ready-made or made independently. But a natural question arises: what capacity should the tank be? After all, a small tank will not give the desired effect, and too much will cost a pretty penny. The answer to this question will help to 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 quadrature;
• duration of inactivity of the main heat source.

Let's determine the capacity of the storage tank using an example standard house area of ​​100 m2, for heating which requires an amount of heat in the amount of 10 kW. Assume that the net downtime of the boiler is 6 hours, the average temperature of the heat carrier in the system is 60 °C. Logically, during the period of time while the heating unit is idle, the battery must 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, which is more household boilers still unable. The required capacity of the 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, in our case it is 60 kW;
• 0.0012 kW / kg ºС is the specific heat capacity of water, in more familiar units of measurement - 4.187 kJ / kg ºС;
• Δt is the difference between the maximum temperature of the coolant in the tank and the heating system, ºС.

So, the water accumulator should contain 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 is enough if the boiler is inactive for 6 hours.

It follows from the previous section that it will not be possible to get rid of an ordinary 200-liter barrel, unless its capacity is at least half a cube. This is enough for a house of 30 m2, and then not for long. In order not to waste time and energy in vain, it is necessary to

From the point of view of placement in the boiler room, it is better to make a container rectangular shape. Dimensions are arbitrary, the main thing is that their product is equal to the calculated volume. Perfect option- stainless steel tank, but ordinary metal is also suitable.

At the top and bottom, a do-it-yourself heat accumulator must be provided with nozzles for connecting to the system. So that the steel walls do not bulge outward with water pressure, the structure must be tightened with ribs or jumpers.

The battery tank must be well insulated, including from below. For this purpose, foam with a density of 15-25 kg / m3 is suitable, or mineral wool in plates not less than 105 kg/m3 of density. Optimal Thickness heat-insulating layer - 100 mm. The resulting apparatus, 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, then you should install it yourself on a metal stand, not forgetting to insulate lower part. The goal is to raise the tank above the level of the batteries.

Wiring diagram

After the tank is in place, it must be properly connected to the piping network. Most Popular standard scheme connection of the heat accumulator shown in the figure:

To implement it, you 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 condensate in the solid fuel boiler, this is what the valve on the left side of the diagram does.

The heat carrier 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 in automatic mode, focusing on the sensor or using a thermostat. One of the schemes of a heating system with a heat accumulator (buffer tank) is shown in the video.

Conclusion

A heat storage tank can make life easier for owners of solid fuel boilers. They don't have to worry about loading fuel at night, which is a big plus. And the heat generator itself will begin to work in an economical mode, developing the highest efficiency. As for electric boilers, then the benefit when installing the drive is obvious.