The heat accumulator for heating boilers: device, purpose + DIY manufacturing instructions

Alexey Dedyulin
Checked by a specialist: Alexey Dedyulin
Author: Natalya Listyeva
Last update: April 2019

How to organize the operation of an autonomous heating system in an economical mode? It is necessary to install a heat accumulator for heating boilers. As a result, efficiency will increase significantly while reducing fuel costs, and the overall cost of maintaining real estate will also decrease.

We will talk about how the unit works, allowing you to collect and store the heat generated by the boiler. We have described in detail all the device options used in everyday life. In our article, we describe the scope of application of heat accumulators and operating rules.

What is a heat accumulator?

A heat accumulator is a buffer tank designed to accumulate excess volumes of heat generated during operation of the boiler. The saved resource is then used in the heating system between scheduled loads of the main fuel resource.

Connecting a properly selected battery allows you to reduce the cost of purchasing fuel (in some cases up to 50%) and makes it possible to switch to the mode of one load per day instead of two.

Heat accumulator in the heating system
In addition to the function of accumulating the generated heat, the buffer tank protects the cast-iron units from cracking in the event of an unexpected and sharp temperature drop in the working network water

If you equip the equipment with smart controllers and temperature sensors, and automate the heat supply from the storage tank to the heating system, the heat transfer will increase significantly, and the number of portions of fuel loaded into the combustion chamber of the heating unit will decrease markedly.

Features of the internal and external devices

The heat accumulator is a tank in the form of a vertical cylinder made of black or stainless steel sheet of high strength.

On the inner surface of the device there is a layer of bakelite varnish.It protects the buffer tank from the aggressive influence of industrial hot water, weak solutions of salts and concentrated acids. Powder paint resistant to high thermal loads is applied to the outside of the unit.

Heat accumulator with solid fuel boiler
The tank volume varies from 100 to several thousand liters. The most roomy models have large linear dimensions, making it difficult to place equipment in the limited space of a home boiler room

External thermal insulation is made of recycled polyurethane foam. The thickness of the protective layer is about 10 cm. The material has a specific complex weave and an internal polyvinyl chloride coating.

This configuration does not allow particles of dirt and small debris to accumulate between the fibers, provides a high level of water resistance and increases the overall wear resistance of the heat insulator.

Different types of heat accumulators
A heat insulator is not always included with the heat accumulator. Sometimes you have to buy it separately, and then independently mount it on the unit

The surface of the protective layer is covered with a good quality faux leather cover. Due to these conditions, the water in the buffer tank cools much more slowly, and the level of total heat loss of the entire system is significantly reduced.

The principle of operation of a heat-saving product

The thermal battery operates according to the simplest scheme. A pipe from a gas, solid fuel or electric boiler is supplied from above to the unit.

Hot water enters the storage tank through it. Cooling down in the process, it drops down to the location of the circular pump and with its help is fed back to the main passage to return to the boiler for the next heating.

The heat accumulator connected to the boiler
The installation of a heat accumulator prevents overheating of the coolant at the moment when the boiler is operating at full power and provides maximum heat transfer with economical fuel consumption. This reduces the load on the heating system and extends its service life.

A boiler of any type, regardless of the type of fuel resource, works in steps, periodically turning on and off to achieve the optimum temperature of the heating element.

When work stops, the coolant enters the tank, and in the system it is replaced by a hot liquid that has not cooled due to the presence of a heat accumulator. As a result, even after the boiler is turned off and in passive mode until the next fueling, the batteries remain hot for some time, and warm water comes from the tap.

Varieties of heat storage models

All buffer tanks perform almost the same function, but have some design features.

Manufacturers produce storage units of three types:

  • hollow (not having internal heat exchangers);
  • with one or two coilsproviding more efficient functioning of the equipment;
  • with integrated water tanks small diameter, designed for the correct operation of the individual complex of hot water supply of a private house.

Connect the heat accumulator to the heating boiler and the communication wiring of the home heating system by means of threaded holes located in the external case of the unit.

How does a hollow aggregate work?

The device, which does not have a coil or a built-in boiler inside, is one of the simplest types of equipment and is cheaper than its more sophisticated counterparts.

It is connected to one or several (depending on the needs of the owners) sources of energy supply through central communications, and then through pipes 1 ½ it is routed to consumption points.

It is planned to install an additional heating element that operates on electrical energy.The unit provides high-quality heating of residential real estate, minimizes the risk of coolant overheating and makes the operation of the system completely safe for the consumer.

Hollow heat accumulator
When the apartment building already has a separate hot water supply system and the owners do not plan to use solar thermal sources to heat the room, it is advisable to save money and install a hollow buffer tank in which the entire useful area of ​​the tank is given to the coolant, and not occupied by coils

Heat accumulator with one or two coils

A heat accumulator equipped with one or two heat exchangers (coils) is a progressive version of equipment with a wide range of applications. The upper coil in the design is responsible for the selection of thermal energy, and the lower one carries out intensive heating of the buffer tank itself.

Heat accumulator circuit with coils
A device equipped with heat exchangers has a higher price than a hollow unit, but the costs are quite justified. The device significantly expands the functionality of the system and makes its operation much more efficient.

The presence of heat exchange nodes in the unit allows you to get hot water for domestic use around the clock, heat the tank from the solar collector, heat the house paths and make the most efficient use of useful heat for any other convenient purposes.

Module with internal boiler

The heat accumulator with a built-in boiler is a progressive unit that not only accumulates excess heat generated by the boiler, but also ensures the supply of hot water to the tap for domestic purposes.

The internal boiler tank is made of stainless alloy steel and equipped with a magnesium anode. It reduces the level of water hardness and prevents the formation of scale on the walls.

Large capacity heat accumulator
The owners choose the appropriate amount of buffer capacity on their own, but experts say that buying a tank of less than 150 liters makes no practical sense.

This type of unit is connected to various energy sources and works correctly with both open and closed systems. It controls the temperature level of the current coolant and protects the heating system from overheating of the boiler.

Optimizes fuel consumption and reduces the number and frequency of downloads. It is combined with solar collectors of any models and can function as a substitute for the hydraulic needle.

Scope of the heat accumulator

The heat accumulator collects and stores the energy generated by the heating system, and then helps to use it as rationally as possible for efficient heating and providing the living quarters with hot water.

Oversized branded heat accumulator
To purchase a device for accumulating excess heating resource is necessary only in specialized stores. The seller must provide the buyer with a certificate of product quality and complete instructions for use

It works with different types of equipment, but is most often used in combination with solar collectors, solid fuel and electric boilers.

Solar thermal battery

The solar collector is a modern type of equipment that allows you to use free solar energy for everyday household needs. But without a heat accumulator, the equipment is not able to fully function, since solar power acts unevenly. This is due to the change of time of day, weather conditions and seasonality.

Roof solar collector
A solar collector equipped with a heat accumulator is placed on the south side of the site. There, the device absorbs maximum energy and gives an effective return

If the heating and water supply system is powered only from a single source of energy (the sun), at some point the residents may have serious problems with the supply of the resource and getting the usual comfort elements.

The heat accumulator will help to avoid these unpleasant moments and make the most rational use of clear, sunny days for energy storage. To work in the solar system, he uses the high heat capacity of water, 1 liter of which, cooling down just a degree, emits the thermal potential for heating 1 cubic meter of air by 4 degrees.

Solar collector and heat accumulator
The solar collector and heat accumulator make up a single system, which makes it possible to use solar energy as the only source for heating a house

During peak solar activity, when solar collector It collects the maximum amount of light and energy production significantly exceeds consumption, the heat accumulator accumulates surpluses and delivers them to the heating system when the supply of the resource from the outside decreases or even stops, for example, at night.

With options and schemes alternative heating for suburban property, the following article, which we advise you to read, will familiarize you.

Solid fuel boiler buffer tank

Cycling is a feature of work solid fuel boiler. At the first stage, firewood is loaded into the furnace and heating takes place for some time. Maximum power and the highest temperatures are observed at the peak of the burning of the bookmark.

Then the heat transfer gradually decreases, and when the firewood finally burns out, the process of generating useful heating energy stops. According to this principle, all boilers operate, including long burning appliances.

It is not possible to precisely configure the unit for the generation of thermal energy with reference to the level of consumption required at any given moment. This function is available only in more advanced equipment, for example, in modern gas or electric heating boilers.

Therefore, directly at the time of ignition and during the actual power output, and then in the process of cooling down and the forced passive state of the equipment, thermal energy for proper heating and hot water heating may simply not be enough.

But during the peak functioning and the active phase of fuel combustion, the amount of energy released will be excessive and most of it will literally “fly into the pipe”. As a result, the resource will be spent irrationally, and the owners will have to constantly load new portions of fuel into the boiler.

Large buffer tank
In order for the house to be heated for a long time after turning off the solid fuel boiler, you need to purchase a large buffer capacity. It will not be possible to accumulate a substantial amount of the resource in a small tank and its purchase will be a waste of money

The solution of this problem is the installation of a heat accumulator, which at the time of increased activity will accumulate heat in the tank. Then, when the wood burns out and the boiler goes into a passive standby mode, the buffer will transfer the collected energy coolant, which will warm up and begin to circulate through the system, heating the room bypassing the cooled device.

Reservoir for electrical system

Electric heating equipment is a rather expensive option, but it is sometimes installed, moreover, as a rule, in combination with a solid fuel boiler.

Usually electric type of heating suit where other sources of heat are unavailable for objective reasons. Of course, with this method of heating, electricity bills are seriously increased and home comfort costs owners a lot of money.

Buffer tank near the boiler
A buffer tank must be installed directly next to the boiler. The equipment has solid dimensions and in a private house a special room will have to be allocated for it. The system will fully pay for itself in 2-5 years

In order to reduce the cost of paying for electricity, it is advisable to use the equipment to the maximum during the period of preferential tariffication, that is, at night and on weekends.

But such an operating mode is possible only if there is a capacious buffer tank where energy generated during the grace period will accumulate, which can then be spent on heating and supplying hot water to residential premises.

DIY energy storage

The most simple model of a heat accumulator can be made with your own hands from a finished steel barrel. If this is not available, you will have to purchase several sheets of stainless steel with a thickness of at least 2 mm and weld from them a suitable-sized container in the form of a vertical cylindrical tank.

Eurocube in the trunk
It is not recommended to use a eurocube for the manufacture of a heat accumulator. It is designed for contact with a coolant having an operating temperature of up to + 70 ºС and simply can not withstand hotter liquids

DIY Making Guide

To heat the water in the buffer, you will need to take a copper tube with a diameter of 2-3 centimeters and a length of 8 to 15 m (depending on the size of the tank). It will have to be bent into a spiral and placed inside the tank.

The battery in this model will be the top of the barrel. From there it is necessary to withdraw the branch pipe for the exit of hot water, and from the bottom to make the same for the cold entry. Equip each branch with a crane to control the flow of liquid into the accumulation zone.

Steel rectangular tank
In an open heating system, a rectangular steel tank can be used as a buffer tank. In a closed system, this is excluded due to possible jumps in internal pressure

At the next stage, it is necessary to check the container for leaks, filling it with water or lubricating the welds with kerosene. If there is no leak, you can proceed to create an insulating layer that will allow the liquid inside the tank to stay hot for as long as possible.

How to insulate a homemade unit?

First, the outer surface of the container must be thoroughly cleaned and degreased, and then primed and painted with heat-resistant powder paint, thus protecting it from corrosion.

Then wrap the tank with glass wool insulation or rolled basalt cotton wool with a thickness of 6-8 mm and secure it with cords or ordinary tape. If you wish, cover the surface with sheet metal or “wrap” the tank in a foil film.

Damaged heat insulator for heat accumulator
Do not use extruded polystyrene foam or polystyrene for insulation. With the onset of cold weather, mice can be found in these materials looking for a warm place for winter living

In the outer layer, cut openings for the branch pipes and connect the tank to the boiler and heating system.

The buffer tank must be equipped with a thermometer, internal pressure sensors and an explosive valve. These elements allow you to control the potential overheating of the barrel and occasionally relieve excess pressure.

Accumulated resource consumption rate

It is impossible to accurately answer the question of how quickly the heat accumulated in the battery is consumed.

How long will it work heating system on a resource collected in a buffer tank depends on such items as:

  • Actual storage capacity
  • level of heat loss in a heated room;
  • outdoor temperature and current season;
  • set values ​​of temperature sensors;
  • useful area of ​​the house, which must be heated and supplied with hot water.

Heating a private house with a passive state of the heating system can be carried out from several hours to several days. At this time, the boiler "rests" from the load and its working resource is enough for a greater amount of time.

Rules for safe use

Do-it-yourself heat accumulators made at home have special safety requirements:

  1. Hot elements of the tank should not adjoin or in any other way come into contact with flammable and explosive materials and substances.Ignoring this item can provoke a fire of certain objects and a fire in the boiler room.
  2. A closed heating system assumes a constant high pressure of the coolant circulating inside. To ensure this point, the design of the tank must be completely tight. In addition, it is possible to strengthen its body with stiffening ribs, and equip the lid on the tank with durable rubber gaskets that are resistant to intense operating loads and elevated temperatures.
  3. If an additional heating element is present in the design, it is necessary to very carefully insulate its contacts, and the tank must be grounded. In this way, it will be possible to avoid electric shock and short circuit, which can disable the system.

Subject to these rules, the operation of a self-made heat accumulator will be completely safe and will not cause the owners any problems and troubles.

Conclusions and useful video on the topic

How to correctly calculate the capacity of the heat accumulator for a home heating boiler that runs on solid fuel. All the nuances and details of the necessary calculations.

How to make a large-capacity heat accumulator with a convenient and practical removable cover with your own hands. Step-by-step instructions with explanations.

Why is it beneficial to use heat accumulators in a home heating system. A good example of cost savings with a significant increase in the level of comfort in a residential building.

Installing a heat accumulator for a home heating system is very profitable and economically justified. The presence of this unit reduces the labor involved in kindling the boiler and allows you to bookmark the heating resource not twice a day, but only once.

The fuel consumption required for the correct operation of heating equipment is significantly reduced. The use of the generated heat is carried out in the optimal mode and is not wasted. The costs of heating and hot water are reduced, and living conditions are becoming more convenient, comfortable and enjoyable.

Tell us how the heat calculator was installed on your boiler. Share the technological subtleties of the process and impressions about the efficiency of the device. Please leave comments in the block below, post photos, ask questions about controversial issues.

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Visitors Comments
  1. Sergei

    If there is no stainless steel tank or there are no funds for the manufacture of a thermal accumulator from the specified material, then this device can be made from a metal barrel with a volume of at least 200 liters. It is better to use mineral wool as insulation, wrapping it with thick foil or thin metal from the outside. For such a design, one coil from a copper pipe is enough, in addition, it can be combined with a heating element. Be sure to install two taps that block the water at the inlet and outlet.

  2. Stepan

    I was dealing with this buffer. I wanted to save on his purchase, because the finished ones are expensive, and when you are building, there is little money.
    I decided to weld such a tank myself. I had lumps of iron, I cut as much as I could per ton of water, so that with a margin.True, the heating master immediately rejected my product, such as a rectangular one, it is impossible, from pieces of different sizes, too. Well, I'm stubborn, cooked as I thought. We began to fill it, and he broke. And it’s without pressure, just the weight of water.
    I had to order at the factory, already in the form of a barrel, then sheathe it with insulation and make the filling. But anyway, it turned out to be more profitable than buying ready-made for my volume. In the boiler room there is no special beauty.