Buffer tank for solid fuel boiler

Many of us are concerned about efficiently heating our homes, particularly in light of the ongoing rise in energy costs. The buffer tank is a crucial part of a well-functioning heating system, especially when utilizing a solid fuel boiler. However, what is a buffer tank exactly, and why is it significant?

Consider your heating system to be a rush-hour motorway. There are instances when there is more traffic than the road can manage, which causes delays and congestion. It’s similar to having a traffic jam in your heating system when your solid fuel boiler produces more heat than your house requires at any given time. This is where the buffer tank comes into play; it functions much like a large parking lot, holding onto extra heat until your house requires it, so avoiding overheating and guaranteeing a constant, comfortable temperature.

Although buffer tanks come in a variety of sizes and forms, their main purpose is still to balance the supply and demand of heat in your house. Usually, they are insulated to keep heat loss to a minimum, maintaining energy efficiency and using less fuel. Additionally, they lessen the frequency of start-up and shut-down cycles, which over time can wear out the equipment and extend the life of your boiler.

However, in what way does a buffer tank help a solid fuel boiler system specifically? Boilers that run on solid fuels—such as coal, wood, or pellets—function differently from boilers that run on conventional gas or oil. Your home’s temperature may fluctuate because they produce heat in spurts rather than continuously. By mitigating these oscillations, a buffer tank creates a more stable and cozy interior environment.

The main purpose of the buffer tank

The buffer tank, also known as a heat accumulator, is designed to store generated heat energy for later, more sensible use in the home’s heating and hot water supply. It can be utilized with equipment that runs on solid fuel as well; let’s look at three particularly noteworthy and varied examples.

• The most commonly used variant is a bundle "solid fuel boiler – buffer tank". The operation of such a pair has already been mentioned in passing above, but now – a little more in detail.

There is always a noticeable cyclicity when using home solid fuel boiler equipment.

Thus, the boiler is filled with firewood for the first stage. When they ignite, maximum power is gradually attained rather than all at once. The highest temperatures are recorded during the fuel load’s maximum combustion phase. After that, there is a phase of gradually decreasing heat output, and when the tab completely burns out, the process of generating heat energy comes to an end. This is a feature shared by all boilers, short and long burning alike—the only distinction being the length of the periods (the only exceptions are those that have an automated pellet fuel supply).

It is not possible to attain the exact configurations of heat energy generation that are found in contemporary gas and electric boilers, with respect to the required current level of its consumption. Therefore, there may not be enough heat energy for the heating system to operate normally during the ignition period, reaching the rated output, cooling, and—more importantly—forced downtime of the boiler equipment. However, it is obviously excessive during the peak phase of combustion, and a significant portion of it literally "goes down the drain." This leads to needless fuel consumption and the requirement for frequent loading.

• Electric heating – an expensive option, and yet such boilers are put, and often – in conjunction with solid fuel boilers. However, it is naturally more profitable to use this principle of heat energy generation during the period of preferential tariffs – at night or on Sundays.

The use of the nightly discounted electricity rates for heating will be maximized with thermal storage.

The answer is to use the energy produced by the electric equipment during the day and turn it on to its maximum during the hours when the cost per kilowatt is lowest.

• Solar collectors are gradually ceasing to be "exotic". This free (if not to count the initial investment in equipment) source of heat energy is capable of, if not fully satisfy the need for it, then at least make a significant contribution to the common "piggy bank".

The effectiveness of using solar collectors for heating is contingent upon the presence of an accumulating tank.

It goes without saying that the availability of solar energy varies greatly depending on the time of day and the surrounding meteorological conditions. While relying solely on one of these sources of heat is not feasible, making the most of bright, sunny days is.

Prices for various manufacturers’ solid fuel boilers

solid fuel boiler

Evidently, the need to store heat energy during the times of maximum production for later, sensible use during the heating system’s operation phase, when heat input is either negligible or nonexistent, unites all of the aforementioned examples. In this capacity, buffer tanks (also known as heat accumulators) are used.

Their work is based on the straightforward premise that water with a high heat capacity is the starting "point." A cubic meter of air can be heated by four degrees with just one liter of water cooling down by one degree, according to a comparison of the thermal properties of various substances. Therefore, if energy is transferred to a specific volume of water that is enclosed in dependable thermal insulation during the peak energy production period, this "charge" might be sufficient to heat the building for a predetermined amount of time in the event that the external energy supply is cut off for any number of reasons.

Now let’s examine the diagram:

Operation of the buffer tank (heat accumulator) in general

In other words, a buffer tank, also known as a heat accumulator (TA in the diagram), is a vertically designed, solid, hermetically sealed, well-insulated tank, usually cylindrical in shape. The vessel is cut with multiple pairs of pipe connections; in the most basic scenario taken into consideration for this example, there are two pairs of pipe connections. One of them is linked to the solid fuel boiler (CT) on the "small circuit," and the other one is connected to the building’s general heating circuit (OK). Every circuit has its own coolant circulation system and is self-contained.

• The first stage of operation – the boiler is loaded and started. The pine circulation pump of this "small circuit" (Nkt) provides pumping of the coolant through the boiler heat exchanger. In this case, the boiler is supplied from the lower area of the heat accumulator, and the heated coolant is supplied to its upper part. At such scheme of work vertical mixing of the heat-carrier is weakly expressed – due to the essential difference in density of hot and colder liquid medium. In other words, there will be more pronounced gradual filling with hot water of the entire volume of the buffer tank.

It turns out that the fuel energy is not lost and is not released into the atmosphere (apart from the losses that are unavoidable and are indicated by the equipment’s passport efficiency). Because of the heat accumulator’s excellent thermal insulation, the heat energy produced by burning the fuel tab is stored for a long period of time—often for days or even longer.

• The second stage – the fuel charge is completely burned out, there is no inflow of heat energy. But the heating system does not stop working. Own circulation system with pump (Nock) ensures pumping of the heat carrier through the heat exchange devices (heating radiators). In this case, the supply pipe is connected in the upper part of the buffer tank, i.e. heated water is taken in, and cooled water is supplied from the bottom through the return pipe. And again – there is no intensive mixing, because of the difference in density. The heat accumulator gradually gives up its "heat charge", cooling from the bottom to the top.

Although the cycles in the example are depicted separately, energy is actually transferred to the radiators during the boiler firing process. As a result, the buffer tank gathers precisely the excess heat that is currently unclaimed. By choosing the best heat accumulator, installing and adjusting the entire heating system correctly, minimizing thermal energy losses, and utilizing the fuel’s full energy potential, the owners will have a fully "charged" storage heat source available by the time each wood is burned.

When it comes to electric boilers, the configuration is designed to optimize the amount of heat produced during the preferred tariff and subsequently utilize it during the day.

Variety of buffer tank designs and connection schemes

We will examine the design characteristics of the primary buffer tank types in this section of the publication, as they can differ significantly.

Basic design types of heat accumulators

Illustration	Characteristic features of the design of the heat accumulator	Features of application
	This is a buffer tank of the simplest construction. It realizes a direct connection of both the boiler circuit and the heating circuits, without the use of additional heat exchange devices.	The option applies in the following cases: – When the levels of permissible working pressure in the heating circuits and the boiler circuit, as well as in the buffer tank itself, have equivalent values; – When a single thermal fluid is used in all circuits. (If the above requirements cannot be met, the use of a buffer tank of this type is also allowed, but with an external heat exchanger – this will be discussed below). – When the boiler temperature coincides with the maximum permissible temperature values in the heating circuits. (This condition can also be leveled by installing on radiators of heating devices of quality regulation of their operation mode – special mixing units).
	An additional internal heat exchanger is located in the buffer tank. This is usually a coil made of smooth or corrugated pipe. The number of heat exchangers can be different. The diagram additionally shows a magnesium anode rod (center), which serves to protect the surfaces of the walls and heat exchangers from solid salt build-up. The lower potential of the anode attracts dissolved salt ions and this element must be cleaned or replaced from time to time.	Typical applications of the scheme: – When the correct operation of the boiler equipment requires pressure that exceeds the operating parameters of the heating circuits or the heat accumulator itself. – When a scheme with several sources of heat energy is used. (e.g. solid fuel + electric boiler, boiler + solar collector or geothermal heat pump). In this case, the order of connection is observed – the lower the thermal head of the source, the lower its heat exchange circuit should be located). – If, for technological reasons, different circuits require the use of different types of heat transfer fluid. This scheme is already characterized by active vertical mixing of the liquid, as the heat exchangers are located at the bottom, and the coolant heated from them, which is in the buffer tank, tends to rise upwards.
	A scheme similar to the first one, with direct connection of the circuits, but with an additionally integrated heat exchanger for the hot water supply system. The cold water is supplied from below. Most of the heat exchanger coils are usually concentrated in the upper part of the vessel. The heat exchanger shall be made of an alloy that complies with the sanitary standards for food water applications.	The optimum use of such a scheme is in the case of a stable hot water consumption in the household, with no pronounced peak periods of consumption.
	Buffer tank, in which the problem of hot water supply is solved by installing a storage tank – a kind of built-in indirect boiler.	This option would be preferable when the hot water consumption in the house is mainly high, but for a short period of time. Such a design is capable of providing peak flow, but requires quite a lot of time to fully heat back the built-in tank.
	In any of the previously given schemes it may be practiced to have multiple pairs of spigots spread over the height of the buffer tank.	This design feature makes it possible to connect circuits requiring different temperature head of the coolant, which ultimately greatly facilitates the fine-tuning of the operating modes of each of them, with minimal loads on the regulating mixing devices. In any vertical vessel there is a so-called temperature gradient, i.e. a difference in the temperature head over the height of the vessel. All that remains is to take advantage of this phenomenon correctly.

Principle schemes of buffer tanks connection

Now, you can acquaint yourself with the most common schemes for connecting buffer tanks based on the device’s features that have been taken into consideration.

Simplified graphic representation of the connection scheme	A brief description of the connection principle
	At functioning of this scheme parameters of temperature and pressure in the system are the same. Single coolant type. The temperature in the boiler supply pipe and at the outlet of the buffer tank is maintained at the same level, and the final regulation of the heating system is carried out at the radiators by quantitatively changing the coolant circulating through them.
	Despite the similarity with the first one, this scheme is more rational and efficient. Adjustment of the heating devices operation modes is already qualitative, i.e. according to the principle of changing the coolant temperature in each of the heat exchange points. For this purpose, additional mixing units with thermostatic principle of action are used. The accumulated thermal "charge" of the buffer tank is spent much more economically, which, accordingly, expands the possibilities of its use in terms of time.
	This scheme has already been mentioned in the table above. In conditions when it is necessary to ensure different pressure in the boiler and heating system circuits, or if there is a need to use different compositions of the coolant, circulation in the "small" circuit goes through the coil-heat exchanger built into the accumulator.
	This variant is for the same conditions as in the previous case, but when for a number of reasons the scheme shown in the line above cannot be realized. Options: – The contact area of the heat exchanger built into the buffer tank was insufficient for efficient heating of the heating medium for the heating circuits. – In the general scheme already installed heat accumulator of the simplest type, but modernization of the heating system leads to the need to separate the contours of the boiler and radiators. In order not to purchase a new expensive buffer tank, it will be more reasonable to build an "intermediate link" between the small circuit and the heat accumulator – an external heat exchanger.
	Uncomplicated in execution scheme with the organization of flow heating of water for domestic use. The variant is designed for uniform consumption, without pronounced mass hot water withdrawals.
	Buffer tank with integrated hot water supply tank. The situation is the opposite – such a scheme is more useful when the household water consumption pattern requires a single large volume of hot water, but then it is necessary to make a rather significant pause for the full heating of the next "portion".
	Scheme in which two independent heat sources are connected to the buffer tank. In the example shown it is, in addition to the solid fuel boiler, a solar collector, although a second (including electric) boiler can also take its place. [Depending on the applied equipment and specific operating conditions, one of the sources becomes the main one, and the second one either constantly contributes to the heat piggy bank, or is switched on as needed, when it is necessary to "warm up" the volume of the heat carrier.
	Multivalent scheme, when three (may be more) heat generators are used. In this case, a solid fuel boiler acts as a high-temperature source, which, again, can only act as an "accompaniment" to other, low-temperature sources, such as a heat pump (independent of either the time of year or the current weather conditions) and a solar collector. The electric boiler shown in the diagram more often plays an auxiliary role. The arrangement of the circuits is top-down, from top to bottom, as their heat head decreases.

Most people are aware that the schemes are provided in an extremely simplified format solely to serve as a visual aid for the principle of work. In actuality, a heating system with a buffer tank, connected energy sources, and a solid fuel boiler can function as a very intricate branching "organism" with an automated control and regulation system for operating modes. Expert specialists are responsible for the design and implementation of these systems.

We can demonstrate the design of the subsequent hardware filling as an example:

Multivalent system for the house’s hot water and heating

1. The solid fuel heating boiler is the primary source of high temperature heat.

Two: an extra electric boiler for heating that was turned on when there were favorable electricity rates.

3. A unique sub-mixing unit has been installed in the main boiler circuit to ensure rapid heating without the unfavorable effect of "cold return."

4. A solar station with a solar collector serves as an extra heat source. It might very well become the primary source of heating if the weather is clear.

5. The buffer tank, also known as the heat accumulator, which unifies the heating circuits and heat energy sources into a single system.

6. A conventional heating circuit that operates at a high temperature and uses convectors or radiators with quantitative temperature control.

7. Low-temperature heating: a "warm floor" of water with a separate mixing unit and coolant temperature regulation.

The eighth hot water supply circuit is flow-type, featuring a mixing unit and forced circulation to keep the water in the DHW pipes at the desired temperature.

Additionally, the buffer tank itself can serve as a direct source of heat energy. It is customary to install electric heating elements in them; these components are connected to thermostatic control equipment and are only turned on when required. TENS will compensate for the current heat deficit, so you can occasionally avoid melting the boiler again.

A thermostat is integrated into the flange-type heating element, making it ideal for future installation in the buffer tank.

These heating elements can be bought separately; in models made specifically for this use, the coupling or flange attachment system is fitted to the heat accumulator spigots. Furthermore, certain heating elements come pre-installed with a thermostatic regulator, meaning they don’t need an extra connection to external temperature sensors. When the temperature in the buffer tank drops below the predetermined minimum, they will activate on their own.

To summarize: What are the advantages and disadvantages of using buffer tanks??

The following are specific "pluses" of autonomous solid fuel heating systems with heat accumulators:

• The energy potential of solid fuel is utilized to the maximum extent possible. Accordingly, the efficiency of boiler equipment increases sharply.
• The system operation will require much less human intervention – from reducing the number of boiler fuel loads to expanding the possibilities of automating the control of operating modes of various heating circuits.
• The solid fuel boiler itself receives reliable protection from overheating.
• The system operation becomes smoother and more predictable, differentiated approach to heating of different premises is provided.
• There are great opportunities for modernization of the system, including – with the launch of additional sources of thermal energy, without dismantling the old ones.
• In most cases, the problem of hot water supply to the house is solved at the same time.

Some peculiar disadvantages exist, and you should be aware of them as well:

• A heating system equipped with a buffer tank is characterized by very high inertia. This means that from the initial ignition of the boiler to the nominal operating mode will take quite a long time. It is unlikely to be justified in a country house, which in the winter period the owners visit only on weekends – in such situations requires rapid heating.
• Heat accumulators are bulky and heavy (especially – when filled with water) designs. They require sufficient space and a well-prepared, reliable foundation. And – in the vicinity of the heating boiler. This is not possible in every boiler house. In addition to this, there are difficulties with delivery, unloading and often with bringing the tank into the room (it may not fit through the door). All this should be taken into account in advance.
• The disadvantages include the very high price of such devices, which sometimes even exceeds the cost of the boiler. This "minus", however, brightens the expected effect of savings from a more rational use of fuel.
• The heat accumulator will fully reveal its positive qualities only if the nameplate capacity of the solid fuel boiler (or the total capacity of other heat sources) will be at least twice higher than the calculated value required for effective heating of the home. Otherwise, the purchase of a buffer tank seems unprofitable.

And how do you figure out how much heat capacity a house needs to be heated? These thermotechnical calculations must be carried out when making a boiler purchase and scheduling the installation of heating radiators. You can finish the calculations on your own if you follow the algorithm that is fully described in the portal publication on heating calculations based on premises area. There’s a useful calculator there as well.

How to choose a buffer tank?

The main criteria for selecting a heat accumulator

There are several considerations that need to be made when selecting a heat accumulator, including the device’s design and installation specifics.

• First of all, the "thermal charge" of the buffer tank directly depends on its capacity. The total amount of water must be such that not a single kilowatt of energy "goes to the side", so that all excess heat is accumulated in the accumulator. The volume is calculated according to a special algorithm, and below in the article this question will be paid attention to it.
• The permissible pressure for which the vessel is designed is important. This indicator should not be lower than the pressure in any of the heating circuits.
• Both of the above parameters impose their imprint on the size and weight of the buffer tank. For heat accumulators designed for high pressure values, usually used tanks with toroidal top and bottom lids. If a device to the existing heating system is purchased, it is necessary to immediately consider the question of how it will be brought into the boiler room – it may be necessary to remove or even expand the doors. When estimating the weight of the product, the weight of the water when the tank is completely filled must be taken into account. Sometimes for a buffer tank it is even necessary to strengthen the site (underfill the foundation slab).

Many factors need to be considered when choosing a buffer tank, including its size, construction material, volume, and suitability for the intended space.

• Depending on the selected connection scheme and the tasks assigned to the heat accumulator, a model with or without the required number of heat exchangers is selected.
• An important criterion is the material of construction of the inner vessel of the thermal accumulator. It is preferable, of course, to choose stainless steel – it is more reliable and durable, but from the point of view of cost more favorable seem to be tanks made of carbon steel with a special coating that prevents corrosion.
• High-quality thermal insulation is the most important prerequisite for the efficiency of the buffer tank.
• It is necessary to familiarize with the possibility of connecting to the selected heat accumulator pipe circuits, additional heating elements, control and measuring devices, devices to ensure the safety of operation. The fact that welded connections are absolutely excluded – only flanged or threaded couplings are allowed is taken into account.
• In the immediate vicinity of the heat accumulator (in some models – directly on the tank) is installed safety group – pressure gauge and safety valve. Check the product passport – if they are not included in the factory delivery set, they must be purchased separately.
• When buying a buffer tank, you should think about the fact that it is desirable to install shut-off valves and visual control devices for temperature level (preferably also for pressure) on all used connections at once. If these elements are not included in the delivery set of the heat accumulator, you will have to buy them separately, but so that they exactly fit the chosen model.
• It is recommended to install dirt filters at all inlets to the buffer tank.
• Some models are equipped with an automatic air vent. If it is not available, it will have to be purchased for installation in a specially provided socket in the upper part of the appliance or in the topmost pipe of the vessel.

Recall that making any personal "improvements" to the buffer tank’s design is strictly prohibited because it directly affects the issues of guaranteeing the general safety of residing in the home.

The cost of heat accumulators for systems with heating

heat accumulators

How to calculate the required capacity of the thermal storage tank?

If the heating system is designed from the ground up, it is best to leave the calculations to qualified experts. On the other hand, there are instances in which independent calculations are required. For instance, a building may already have an electric or solid fuel boiler, but the owners have chosen to add a buffer tank to increase the system’s efficiency. What is the required minimum volume to make this work?

• Calculation is based on the formula for the amount of heat energy required to heat a certain mass of substance by a certain number of degrees:

Q is equal to m × c × Δt.

Q is the necessary quantity of heat;

M is the substance’s mass

С is its heat capacity in specifics.

Temperature differential, Δt.

• In our case we deal with water, so the tabular value of heat capacity of the substance is known

A = 1,16 kW/m³×°C and B = 4,19 kJ/kg×°C and 1,164 W/h/kg×°C.

Let us modify the expression in order to obtain the mass value:

M is equal to Q / (s × Δt).

• Since heat losses are inevitable in any case, we also take into account the efficiency factor of the boiler k (according to its data sheet):

Q / (k × s × Δt) = m.

• It would seem that everything? No, because in the process of boiler firing a part of energy will not be accumulated, but will be immediately consumed for heating needs, and it will not be necessary to accumulate it. So, it is necessary to calculate the value that will show the difference between the heat energy produced by the boiler and its current consumption.

The owners are aware of the boiler’s passport power (which must be calculated starting from the maximum). If the boiler has been used, the owners are undoubtedly aware of its "burrow," or the duration of time that the fuel charge burns completely (this can also be referred to as the boiler activity period).

The computation of the necessary heat required to heat the house—which was previously mentioned—can be done on their own by clicking on the suggested link.

As a result, figuring out how much residual heat needs to be kept in the buffer tank just requires basic math.

• And now it remains to determine Δt. And this is nothing but the temperature difference between the supply and return pipes at the boiler inlets. The necessary values can be obtained by the usual experimental way – take temperature readings at normal, steady-state operation of the heating system.

The final computation is easy to do with all of the initial data at hand. Although the value will be given in kilograms, it shouldn’t be too difficult to convert it to volumetric units for water given that its density is roughly equal to 1 kg per dm³.

The method of calculation for an electric boiler is the same. The sole distinction is that, naturally, the equipment’s operating time here does not correspond to the fuel tab’s burning time, but rather to the six-hour nightly preferential tariff, which runs from 00.00 to 06.00.

Many people give up on independent calculations because they are intimidated by mathematical and physical formulas. Don’t worry, a handy calculator that already has all the relationships listed below will help you quickly and precisely complete the calculation.

Calculator for calculating the minimum required volume of the buffer tank for the boiler

It should be known that the buffer capacity volume that results is a minimum volume. Stated differently, the model of choice should be chosen only as a kind of boundary or reference point, below which it is not permitted to go.

In the world of home heating and insulation, a buffer tank for a solid fuel boiler stands as a key player. This essential component acts as a reservoir, storing hot water produced by the boiler, ensuring a consistent and efficient supply of heat to your home. By maintaining a steady temperature, it minimizes the fluctuations often associated with solid fuel systems, promoting better energy utilization and comfort. The buffer tank also plays a crucial role in protecting the boiler from damage caused by frequent cycling, extending its lifespan and reducing maintenance costs. Whether you"re looking to enhance the performance of your heating system, improve energy efficiency, or simply enjoy a more comfortable living environment, investing in a buffer tank for your solid fuel boiler proves to be a smart and worthwhile decision.

A brief review of models of heat accumulators for solid fuel boilers

For the sake of completeness, the following is a quick rundown of the popular manufacturers’ heat accumulator models that are known for their high caliber output:

Model name, manufacturer	Illustration	Brief description of the model	Average price level (as of 10.2016)
"Tesy V 200 60 F40 P4", Bulgaria		Inexpensive, compact and lightweight heat accumulator without additional heat exchangers. For boilers with output up to 10 kW. Pressure – up to 3 bar. Internal volume – 200 liters. Dimensions: height 1200 with a diameter of 600 mm. Weight without water – 43 kg. Models in this range up to 500 liters are equipped with non-removable thermal insulation. Larger – thermal insulation is supplied optionally, by customer"s order.	35 th. rub.
"SunSystem P 500", Bulgaria		"Empty", without internal heat exchangers buffer tank, but with provided possibility to connect electric heaters (TEN). Volume – 500 liters, pressure – up to 3 bar. Recommended for solid fuel boilers up to 17 kW. Dimensions: height 1660 with cylinder diameter 850 mm. Empty weight – 111 kg.	48 th. rub.
"S-Tank AT 1000", Belarus		The 1000 liter model belongs to the line of inexpensive buffer tanks without built-in heat exchanger. Possibility to connect solid fuel boilers and other alternative heat sources. Working pressure – up to 6 bar, thickness of thermal insulation – 70 mm. Multidirectional, 90º turned mounting holes with 1 ½ inch female threads for circuits and ½ for instrumentation. Model size – height 2020 with diameter 920 mm. Weight in unfilled state – 130 kg. The product line includes thermal accumulators with volumes from 300 to 5000 liters.	50 – 60 thousand. rub.
"Hajdu PT 750 C", Hungary		Buffer tank with one built-in heat exchanger and possibility to install additional heaters. Volume – 750 liters, maximum pressure up to 6 bar, suitable for boilers up to 25 kW. Important – the products are not equipped with thermal insulation – it is either performed independently or ordered as an additional option for a separate fee. Height – 1910 mm, cylinder diameter – 790 mm. Empty weight – 171 kg.	78 ths. rubles.
"S-TANK AT MONO 1000", Belarus		Similar in structure and dimensions to the model shown above "S-Tank AT 1000", but with a built-in single heat exchanger, which expands the possibilities of using other heat sources. Empty weight – 175 kg.	85 thousand. rub
"Austria Email PSRR 500, Austria		High-quality, efficient model with two integrated heat exchangers. Volume of heat exchangers 7,9 and 11 liters with active heat exchange area 1.2 и 1.8 m² respectively. The inner tank is made of high-grade steel St 37-2. ECO SKIN 2 thermally insulated.0, minimizing heat losses. Volume – 500 liters. Permissible pressure – up to 3 bar. Suitable for boilers with heat output up to 13 kW. Dimensions: height 1275 with a diameter of 850 mm. Weight without water – 113 kg. Manufacturer provides 7 years warranty.	105 ths. rub.
"Heatleader MB215 500-0-0", Russia		Buffer tank with a flowing hot water circuit, with the possibility of organizing it on a recirculation scheme. Volume – 500 liters. Removable casing with 50 mm thick thermal insulation. Included – safety group with valve calibrated for maximum pressure in the tank of 6 bar. Dimensions – 2000×600×700 mm. Empty weight – 200 kg.	120 thousand. rubles. – with boiler steel tank. 150 thousand. rub. – with stainless steel tank.
"Nibe BUZ 750/200.91", Sweden		Production of a well-known Swedish company specializing in the production of heating equipment. High-quality model with built-in boiler tank for hot water supply. Total volume – 750 liters, of which 200 liters is occupied by the built-in tank. In addition to this, there is a built-in heat exchanger with a heat exchange area of 2.74 m² Maximum coolant pressure: in the tank – up to 3 bar, in the coil – up to 16 bar. Accordingly, the temperatures are 95 and 110 degrees. [Dimensions: 1468 × 964 × 1042 mm. Empty weight – 330 kg.	208 ths. rub.

Thus, it is evident that purchasing a buffer tank is a costly endeavor. The more justifications for the requirement, the more responsible it is to select the best model. See the link for a study on energy-saving electric heaters for homes.

Finally, here is a useful video that explains why buffer tanks are necessary in heating systems that use solid fuel boilers:

Feature	Description
Capacity	Size of the tank, typically measured in liters or gallons, determining how much water it can hold.
Material	The substance from which the tank is constructed, often stainless steel or enamel-coated steel for durability.
Insulation	The level of insulation around the tank, which affects heat retention and energy efficiency.
Connections	Types and number of connections for pipes, valves, and fittings, facilitating integration into the heating system.
Design	The tank"s shape and design features, influencing its compatibility with the boiler and available space.

Your heating system’s performance and efficiency can be greatly improved by adding a buffer tank to your solid fuel boiler. The buffer tank prevents your boiler from constantly cycling on and off by serving as a thermal store to guarantee a steady supply of hot water.

The capacity of a buffer tank to handle variations in heat demand is one of its main advantages. The boiler’s excess heat is kept in the tank during times of low demand, ready to be used when things pick up. This reduces energy waste and contributes to the maintenance of a more constant and cozy interior temperature.

Furthermore, by lessening the wear and tear brought on by frequent cycling, a buffer tank can increase the lifespan of your boiler. The buffer tank helps to prevent deposits and corrosion by enabling the boiler to run at a more consistent and efficient level. This eventually results in fewer repairs and lower maintenance costs.

Furthermore, adding a buffer tank to your heating system may make it possible to integrate renewable energy sources like heat pumps or solar thermal panels. You can lessen your dependency on fossil fuels and your carbon footprint by keeping any extra energy produced from these sources in the buffer tank.

To sum up, adding a buffer tank to your solid fuel boiler is a smart move that will pay off in many ways for comfort, efficiency, and environmental sustainability. These tanks maximize the performance of your heating system, resulting in cost savings and increased homeowner peace of mind by acting as a buffer between heat generation and consumption.

Video on the topic

Buffer tank

Heat accumulator or buffer tank. And why it is needed. Storage tank or buffer capacity principle

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