How to make a heat accumulator for heating with your own hands. How to make a heat accumulator (buffer tank) with your own hands, is it worth doing it Polypropylene heat accumulator
The internal structure and principle of operation of the heat accumulator for heating boilers is designed to ensure that the required temperature of the heat carrier 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
In fact, this is a tank with a built-in DHW coil and a heat-insulating casing. The purpose of the tank is to accumulate excess thermal energy. After turning off the main source of heating of the coolant, the tank replaces it for a certain time.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
The heat storage tank is a conventional metal barrel with external thermal insulation. A simple heat storage device, however, is highly efficient and indispensable for heating systems. The buffer tank in the section consists of several nodes:- 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, and carrying out repairs if necessary.
Purpose of heat accumulators
The basis of the operation of the buffer tank is due to the fact that the excess thermal energy is accumulated, after which it is used to heat the building and hot water. A heat accumulator in the heating system is needed to maintain a comfortable temperature in a residential building after the main source of thermal energy is turned off.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
The first and obvious drawback: the high cost of the tank. High-quality products made in the EU or in Russia will cost from 25,000 to 300,000 rubles. Another disadvantage: the large dimensions of the product. Often it is necessary to install tanks of 1000 or more liters, which take up a lot of space.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 that are not designed to provide hot water.
Which heat accumulator to choose
It is better to entrust the selection of storage capacity to specialists. You will need to choose a tank that is optimally suited for the type of heating equipment used. The selection of a heat accumulator for a solid fuel boiler and a heat pump may differ. Leading manufacturers in the operating instructions directly indicate for which type of heating system this or that buffer tank is intended. When choosing, pay attention to several technical characteristics:
- Storage container 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 coating 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
To select the required volume of the heat accumulator, you can go three ways. The first is related to the use of special online calculators. You will need to enter the following parameters:- heated area;
- boiler power;
- time of autonomous maintenance of temperature in the heating system after the boiler is turned off.
To get the 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;
- cp - specific heat capacity;
- T2 and T1 - initial and final temperature of water heating in the tank.
- 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
After performing the calculations and determining the desired technical characteristics, you can proceed to the selection of heat accumulators by manufacturer. Not only European products are represented on the market. There are heat accumulators for Russian-made heating boilers, which are not inferior in quality to eminent foreign equipment.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 storage tank occupies an integral place in modern heating systems.
At present, the period of constant increase in prices for the main types of energy carriers, the issue of energy saving and the use of highly economical heating systems is of particular relevance. Especially important is the efficiency of heating systems for country cottages, which use liquid or solid fuel boilers as a heat source.
Typically, the heating system of a private house includes:
- a heating boiler operating on various types of fuel or electricity;
- system of main pipelines;
- heating radiators (convectors).
To improve energy efficiency and reduce fuel consumption, modern heating systems include heat accumulators (heat accumulators). This device is a large volume container, which is included in the heating system, which has a different design and implements different methods of heat exchange.
Today, the industry produces various devices for accumulating thermal energy for domestic purposes. However, most of them have a high cost, a rather complicated connection and the need to insert additional devices into the heating system (temperature sensors, manual and controlled valves, as well as other devices).
At the same time, today there is a sufficient number of home-made designs of heat accumulators that you can make and connect with your own hands. At the same time, their cost in self-manufacturing will be much cheaper, and in terms of their functionality, they are not much inferior to factory designs.
Purpose and functionality of the heat accumulator
The use of heat accumulators is not justified for all types of systems. In the West, they are often used as part of solar heaters. In Russian private houses, they are mainly used in the following two cases:
- when connecting an electric heating boiler to a multi-tariff one, when at night the electric heater is turned on at full power and the battery effectively accumulates heat, and during the day the heating of the living space occurs due to the accumulated energy, and the boiler turns on only to maintain a certain temperature level;
- when heating a dwelling with a solid fuel boiler, when, due to the thermal energy accumulated during the day, a constant supply of coal or firewood is not required at night and the heater is operated in an economical mode.
In addition, the inclusion of a heat accumulator in the heating system can significantly expand its functionality, the main of which can be considered:
- implementation of provision of residential premises with hot water supply;
- stabilization of the temperature regime and microclimate of residential premises;
- a significant increase in the energy efficiency of the heating system, which makes it possible to reduce the cost of using energy;
- allows you to combine several different types of heaters into a single heating system;
- implementation of the possibility of accumulation of excess thermal energy generated by the heating boiler.
Prefabricated heat accumulator designs
Industrially manufactured heat accumulators are a steel tank (usually cylindrical) in the inner cavity of which there are one or more coils through which the main and additional heating circuits are circulated.
Some systems have additional water heating, which is provided by thermal electric heaters placed inside. Factory heat accumulators have various devices for automation and control of water heating.
Self-copying of such devices at home is quite problematic and will cost a little less than its cost in the store. The most complex elements are coils made of stainless or copper tubes, the winding of which is a rather difficult task when solving it at home.
No less complex are the issues of sealing the outlet fittings to which the heating system is connected, and their sealing. Thermal insulation of the battery tank is also a major problem.
The structure of the thermal energy accumulator, which is quite suitable for repetition at home, will be described below. The principle of its work is as follows:
- the coolant, during the operation of the heating boiler at full power, is partially sent to the heat accumulator;
- after turning off the boiler, the heated coolant from the heat accumulator, circulating along, provides heating for residential premises;
- if you place an additional coil inside the device case and connect it to a regular water main, hot water supply to the dwelling will be provided;
- switching the operation of the heating system when powered by a heating boiler or from a heat accumulator is provided by special shut-off and control valves, which can operate automatically or switch manually.
Heat accumulator connection diagram CO - heating system. 1 - automatic coolant distributor;
2 - circulation pump; 3; 4; 5 - shut-off and control valves;
6;7 - temperature sensors.
Tank volume calculation
Usually, in the recommendations for the independent manufacture of heat accumulators for heating private houses, the volume of its tank is more than 150.0 liters. However, the location and the area occupied by the tank depend on this parameter, therefore it is advisable to determine by the calculation method the volume of water needed to heat the room, which should contain the heat accumulator tank.
The initial data for the calculation are the following data:
Q is the specific thermal power required to heat the room in kilowatt-hours;
T is the operating time of the heat accumulator per day, hours
t 1 - temperature of the heat carrier at the inlet to the heating system, ° С;
t 2 - temperature of the coolant at the outlet of the system, ° С;
m is the mass of water, kilogram;
c is the thermal constant (specific heat capacity of the coolant).
The heat balance equation has the form:
Q × T = c× m×(t 1 – t 2 ) (1)
Solving this equation for the mass m we get the formula:
m = Q× T/[ c× (t 1 – t 2 )] (2)
For heating a private house with a heated area of 100.0 square meters, it is required to spend 10.0 kilowatts of thermal energy every hour. Let the operation of the heat accumulator be assumed with the heating boiler turned off for 5.0 hours per knock. We accept the temperature of the coolant at the inlet - t 1 \u003d 80.0 ° С; outlet t 2 =30.0°C. If water circulates in the system, then its specific heat capacity is c = 0.0012 kilowatts divided by a kilogram and a degree Celsius. Substituting the initial data in formula 2 will obtain the required mass of water:
m \u003d 10.0 × 5.0 / \u003d 833.33 kilograms
Thus, the capacity of the tank of the heat storage device must be at least 850.0 liters. Taking into account the thermal inertia of the heating system as a whole and the permissible decrease in the temperature of the coolant, the device will be able to operate in the inertial mode for an additional 2.0 ... 3.0 hours.
In this case, it should be taken into account that the thermal power of the heating boiler, for the normal functioning of the heat storage system, must exceed the thermal power required for heating the premises by 30.0% ... 50.0%.
For the manufacture of a heat accumulator, you can purchase a ready-made metal container of a suitable volume. Water tanks designed for watering garden plots are perfect. Some recommend using plastic containers (such as a Eurocube or a septic tank).
However, when choosing plastic vessels, even those designed for operating temperatures up to 80.0С ... 90.0С, you should know that the reliability of the entire system drops sharply, and it is unlikely that any owner will be pleased to be without heating in winter with a cubic meter of water spilled in the room.
The ideal solution would be to do it yourself. At the same time, knowing the volume of the tank and the area of \u200b\u200bthe room where it will be located, it is not difficult to independently determine the dimensions. For manufacturing, sheet steel with a thickness of at least 2.0 millimeters is suitable.
At the same time, there will be no difficulties with the installation (welding) of the inlet and inlet fittings. If you make a tank in the form of a parallelepiped or a cube, work on its further thermal insulation will be greatly facilitated.
Insulation of the device case
To increase the energy efficiency of the heat storage device and reduce heat losses through the walls of the housing into the atmosphere, it must be insulated. The ideal heat-insulating material is foam sheet, the thickness of which is 100.0 millimeters.
At the same time, the density of the material must be at least 25.0 kilograms per cubic meter (foam grades "PSB-S 25" and higher). It is easily processed, cut to size and it is easy to cut holes for fittings in it. Attach the foam () to the outer walls with glue.
You can also use rolled mineral wool (material "ISOVER"), with a density of 135.0 ... 145.0 kilograms per cubic meter. However, this material is somewhat more difficult to attach to the walls (especially to the bottom of the tank). However, mineral wool rolls are more optimal for insulating cylindrical containers.
Disadvantages of heat storage devices
The disadvantages of heat accumulators include:
- a significant increase in the volume of the coolant, which forces it to be used only as water;
- the need for a significant reserve volume of water, which makes the choice of structures with additional heating using thermal electric heaters more preferable;
- the capacity and dimensions of the tank without additional electrical heating require a large area, which is usually solved by arranging a mini boiler room.
Main conclusions
The inclusion of a storage water heat storage device in the heating system allows:
- use all the advantages of the "night" tariff when using heating electric boilers;
- save any kind of solid fuel;
- increase the energy efficiency of the heating system as a whole.
The heat accumulator is built into the heating system so that the temperature in the entire apartment or house is uniform, and gives off its heat gradually. This can be obtained due to the fact that thermal energy is accumulated very quickly, which is generated during the operation of a solid fuel boiler.
This energy is designed to minimize the heat loss of the house and, if possible, compensate for them by supplying a certain amount of heated coolant to the radiators of the heating system.
So, the principle of operation of this device is as follows: the coolant is sent to the battery in the upper part, and the cooled coolant is discharged from below. Due to this connection, mixing does not occur. With the passage of time and the circulation of the coolant, cold water gradually leaves the battery.
Due to this design, the radiator and the boiler work independently of each other and are able to function normally in their mode. It is worth noting that the radiators in this case will work on approximately the same principle as in a centralized heating system.
With the help of heat accumulators, it is possible not only to maintain a comfortable temperature in the room, but also to provide living people with hot water and greatly reduce the financial costs of heating itself. Do-it-yourself heat accumulator
If the owner of a house or apartment is going to make such a structure on his own, then at first he should find out exactly what functions it performs.
With the help of heat accumulators, it is possible not only to maintain a comfortable temperature in the room, but also to provide living people with hot water and greatly reduce the financial costs of heating itself. By installing such equipment, you can immediately combine several heat sources, forming one common circuit.
We carry out calculations
Before proceeding with the manufacture of a heat accumulator, it is necessary to make all the necessary calculations that will help you choose the right volume of the product. First of all, it should be taken into account that the required amount of thermal energy must match the level of heat loss.
You can try to use a fairly simple principle that does not take into account all sorts of additional factors, since this will be quite enough for heating a private house.
When calculating, it should be taken into account that for every ten square meters of heated area, 1 kW of heat is wasted. This value is very average, but it is best to start from this indicator.
For competent replenishment of heat losses, it is necessary to take into account the moment associated with the volume of water circulating through the heating system, as well as its temperature. Approximately, about 7 thousand kWh will be spent monthly only for heat losses for the house, the heated area of \u200b\u200bwhich is about one hundred square meters. For this reason, the volume of the accumulator should be selected in such a way that it can release a similar amount of heat in a specified period.
It should also be remembered that the temperature range in this battery will be 40 degrees - from 50 to 90. Moreover, these structures are able to function normally even when the boiler is turned off - their energy reserve is enough for eight hours of continuous operation.
The heat accumulator has a certain thermal insulation in its design so that the water does not give off heat to the walls of the tank. It is best to insulate it with modern type thermal insulation materials, as they are able to retain heat for a long time. In principle, a thermal insulation thickness of 10 cm will be sufficient. If the design turns out to be too bulky, then the thickness of this layer can be made somewhat smaller.
Necessary materials and tools
Before starting work, you should stock up on everything you need so that everything is at hand:
- Sheet insulation(the most high-quality product today is mineral wool) - 20 square meters will be quite enough;
- Pipes of suitable diameter through which the coolant will enter the tank;
- Copper tubes or ;
- Cement-sand mortar or a concrete slab of suitable thickness;
- foil tape;
- Sheet metal- you can take galvanized sheet, as it does not rust and does not lend itself to corrosive processes.
Manufacturing
When all the necessary calculations have been made, it was possible to determine the volume of the heat accumulator, and you have everything you need for assembly at hand, you can begin to assemble the structure itself.
If a metal barrel plays the role of a heat accumulator, then it must first be completely cleaned of debris, rust and other contaminants. It is also desirable to treat the product with anti-corrosion compounds, at least from the inside, but it is better to cover them on the outside so that rust does not form for as long as possible.
To do this, it is better to take phosphoric acid, cover the surface of the metal with it, and then, for better waterproofing, treat the barrel with four or even five layers of primer.
The next step is to make sure that the heat does not leave the barrel. This is to ensure that the water remains at a suitable temperature for a long period of time. In addition, thermal insulation is designed to prevent heating of the air surrounding the battery. This will save a lot of energy.
If it was not possible to get mineral wool, then instead of it you can take foam plastic, the thickness of which should be no more than 10 cm. It is quite easy to work with this material - cut and fasten. Moreover, it is quite lightweight.
In the case of mineral wool, it will have to be fixed with foil tape, the density of this insulation is much higher. If necessary, an additional outer casing can be made of tin or other sheet metal.
In the future, a coil should be made, inside which the coolant will move. It is made of copper tubes, the diameter of which should not exceed 30 mm. The length of this structural element directly depends on how large the volume of the heat accumulator is. On average, about 15 meters of this pipe is spent. This element must be connected to the boiler, as hot water will pass through it. The cold water located in the tank will begin to warm up precisely thanks to this coil.
The structure is almost complete. It is necessary to make two holes through which the inlet and outlet pipes will be supplied. In the future, they will need to install shut-off valves.
In the place where this barrel will be installed, a concrete slab should be laid or some other rigid base should be made so that the structure does not move out of place during operation. It can be laid out of brick or pour concrete on the floor yourself.
Modernization of the heat accumulator
The classical design of a heat accumulator was previously described, however, there are several elementary tricks with which you can make the operation of this device more efficient and economical:
- Below you can place another one, the functioning of which will be based on the use. This option is suitable for users who prefer green energy;
- If the heating system has several circuits of work, then it is best to divide the barrel inside into several sections. This will allow in the future to maintain the temperature at a very acceptable level for the longest possible time;
- If financial resources allow, then polyurethane foam can be taken as a heater. This material is much more expensive, but it retains heat much better. The water will keep the temperature for a very long time;
- You can install several pipes at once, which will make the heating system more complex, equip it with several circuits at once;
- It is allowed to install an additional heat exchanger together with the main one. The water heated in it will be used for various household needs - this is quite convenient.
How to connect
At the initial stage, the boiler should be installed according to the diagram. On the pipe that will go to the drive, you will need to put a special safety group and in order to prevent the occurrence of condensate. In the future, a heat accumulator should be connected to the system, and it will need to be connected to the pipe coming out of it.
- Heat accumulators are gaining more and more popularity today. largely due to its characteristics such as efficiency and economy.
- It is possible to load fuel into a boiler connected to a heating system with an integrated heat accumulator once a day, and if the design is more perfect, then the fuel will have to be added once every few days.
- The first start-up of the boiler should be carried out in the presence of appropriate specialists. They will have to check how well the entire system works, whether there is water circulation in the heating, whether there are any leaks, whether the heat accumulator is well insulated, and so on.
- The heat accumulator can be perfectly combined with boilers running on gas or electricity.
Installing a water heat accumulator in the heating system solves many problems at once. With solid fuel boilers, there are generally many benefits: less often to heat and the temperature in the house is more even. This device also helps to make heating more economical, since the boiler operates in the most optimal mode - with the active burning of firewood. Another heat accumulator (TA) allows you to heat with electricity is not so expensive. This is a good savings option for those who have a nightly rate with a significant difference in price compared to the daytime rate. The only thing that stops: high prices for heat storage tanks - hundreds of thousands. There is also a cheaper option - to make a heat accumulator with your own hands. It will cost 20-50 thousand - depending on the volume and the selected material.
Materials, design and insulation
Homemade storage tanks for heating systems are usually made in the form of a cube. Everyone chooses sizes and proportions based on the available area. What is their disadvantage? Most of them are non-hermetic. No, they don't leak and feel very good.
In a closed system, a sealed container is desirable - so that there is no air in the coolant, it is possible to maintain a stable pressure. To achieve this in artisanal conditions is not at all easy, although it is possible.
With and without heat exchanger
There are two types of heat accumulators that are put into heating: with a heat exchanger inside connected to the boiler and without it. In the second case, it's just a container with nozzles. Such TAs are installed if the coolant in the system and the boiler is the same, and if the pressure in all parts of the system is the same. The third limitation is temperature. In heating systems of this type, the temperature inside the boiler and on consumers (radiators, underfloor heating and other devices) can be the same.
At first glance, a heat accumulator without a heat exchanger seems to be more advantageous: direct water heating is more efficient than indirect heating (through a heat exchanger). The costs are less - since the heat exchanger is made of a copper pipe or stainless steel and the length of the pipe is several tens of meters.
But, if you let the water from the boiler through the coil, the boiler heat exchanger will last longer. After all, a small volume will circulate in this circle. The salts dissolved in it will quickly settle, and since there are no new “receipts”, there will be no other deposits. Without a coil, all the coolant in the system will be pumped (including the one in the tank), so the sediment will be ten times more.
What length of pipe to take for a heat exchanger
In most cases, heat accumulators are made with heat exchangers. For this, a coiled copper pipe or cast-iron radiators are used. With this, everything is clear. But how long should the pipe be or how many sections are in the radiator? This must be counted. The exact calculation is long and complicated, but approximately can be calculated as follows:
- According to experimental data, the radiator section has a heat transfer coefficient of about 500 W / sq. m * deg, an inch copper pipe - 800 W / sq. m * deg.
- We also accept that the average temperature difference in the coolant is 10°C.
- To calculate the planned heat reserve, we divide it by the heat transfer coefficient of the material (pipe or radiator). We get the heat transfer area for this case in square meters.
- We are looking for in the data what is the surface area of the material you have chosen (for 1 meter of pipe or 1 section of radiators). To find the footage or number of sections, we divide the resulting heat transfer area by the surface area.
This is an approximate calculation. The data will be a little overestimated, but it's not bad. It is much worse if they are underestimated - the coolant in the heat exchanger will boil before the water in the TA tank heats up. Therefore, it is better to take with a margin.
To make it a little clearer, we calculate the length of the pipe and the number of sections, if it is necessary to transfer 25 kW of heat to the water in the TA. 25000 W / 800 W / sq.m * hail = 3.21 m2. In the case of an inch tube, about 40 m will be required.
For radiators, the calculation is similar: 25000 W / 500 W / sq.m * hail = 5 m2. This is about 20 battery sections.
Which is better - radiators or pipes? In terms of practicality, radiators are better. If it suddenly turned out that the heat transfer made by the heat exchanger is insufficient, you can always add a couple of sections. It’s more difficult with a pipe - you won’t grow it. You will either have to take a longer piece, or be smart about something with the second circuit of the heat exchanger. True, there are still options - add fins (to increase the heat transfer area) or install a circulation pump that will create movement in the tank. This will increase heat transfer.
The pump is easier to install, but it will only work if there is power. So this option is not for all occasions. Unless you have an electric generator or other power source in case of power failure.
What materials are they made from
Independently capacity for heat storage in the heating system is made:
- From ordinary sheet steel 4 mm thick. The most budget option. It is bad that such a tank rusts. But there are technologies and coatings that will allow this process to be prevented/slowed down (description just below).
- From sheet stainless steel from 2 mm thick. There is a problem with the welds. If welded under normal conditions, the alloying metals in the heated area (seams) burn out, so that the seams rust and leak. You can solve the problem by buying a TIG torch and cooking in an argon environment.
- From Eurocube. This is a large plastic container. It doesn't rust, it's sealed. That's just the temperature of the liquid in it should not exceed 72-73 ° C, otherwise it will "lead". In order not to overheat, you will have to increase the volume or reduce the "downtime" between the furnaces.
In general, they make a heat accumulator from large barrels. Under a small system, you can weld two or three two-hundred-liter barrels. Such a container can be put in a small house - up to 60-70 squares.
So that a container made of ordinary steel does not rust, it must be covered with a sealed composition from the inside. For these purposes, a thick film is used, which covers the pools. It is welded to the desired size in place. There are also rubber-like paints or mastics. Some of them are also used for sealing pools, but many are used in various industries. Both films and mastics / paints you need to find those whose temperature regime of use exceeds 100 ° C (or better - 110 ° C). Another option is heat-resistant glass enamel.
When it comes to heat exchangers, they are made from a variety of materials:
Home-made heat exchangers for heat accumulators are usually made in the form of a spiral. For these purposes, annealed copper or corrugated stainless steel pipe is excellent. It is not a problem to bend them, even with a small diameter. These two materials are in the lead. But the corrugated pipe is not very good in terms of heat dissipation. Let it have a larger surface area, but the movement of the coolant along it is difficult. So this is not the best choice. Especially for boilers with low power.
Paired with powerful boilers and in storage tanks of large volumes (from a cube and more), cast-iron radiators performed well. This is a budget option, but it has serious drawbacks. The first is great inertia. Until the radiator itself heats up, there is no heat exchange with water. This increases the heating time of the TA. The second drawback is that cast iron rusts. Maybe not so fast, but still. To prevent rust particles from entering the system, place mud collectors at the outlet of the homemade buffer tank.
Warming
Since the main task is to save as much heat as possible, home-made heat accumulators must be insulated. The two most common materials for these purposes are high-density foam (at least 350 g / m³) and mineral wool. Mineral wool is better to take in mats, it is easier to work with it. In terms of thickness - they take 10 cm on the bottom and sides, the top can be insulated more carefully - 15 cm.
To make a self-made heat accumulator look more presentable, and in order to slightly improve heat saving, you can cover it with foil foam insulation on top of the thermal insulation, sheathe it with plywood, OSB or other sheet material.
A little more difficult with the insulation of the lower part of the buffer tank. Filled with water, it will weigh very solidly, so that many materials will simply crumble, and there will be very little sense from them. There are two solutions:
- As a heat-insulating layer, use foam / gas concrete blocks, on top of which lay several layers of basalt cardboard. It turns out good thermal insulation.
- Make a tank on legs or weld a frame on which to put the container. In this case, you can use any of the heaters - it can be put on mounting foam.
Cellular polycarbonate belongs to the unusual materials that were used to insulate heat accumulators. It itself retains heat well, as it is used in the construction of greenhouses. It can be laid in several layers, bringing the thermal insulation almost to the ideal. In this case, the lining with foil insulation makes more sense: the heat will be reflected back to the tank.
Stiffeners or frame
Do-it-yourself heat accumulator is often made of sheet metal. Its thickness is several millimeters. Even with a volume of 500-700 liters, such a solid capacity is obtained. When filled with water, the walls of the container swell to the sides - the water pressure is considerable.
These are the ties inside the heat accumulator - so that the walls are not squeezed out by water
So that the walls of the container do not sag, you can either weld stiffeners from the inside (as in the photo), or weld the frame from corners and metal strips, and then scald it with metal. When choosing the option with stiffeners, they must be welded along the long side (if any) with a distance of no more than 50 cm. Having welded the transverse strips on opposite sides of the cube, they are connected using metal strips or pins, welding them also with a not too large step .
Examples of homemade heat storage tanks for heating
TA for cheap heating with electricity
This heat storage tank was made for an electric boiler. With its help, heat is stored during the night tariff. The capacity turned out to be large, in order to speed up the process and have a certain power reserve in case of a decrease in the validity of the night tariff, three more heating elements of 2 kW each were embedded. They are connected by a "star" to a three-phase network.
According to materials:
- tank size - 1.5 * 1.5 * 0.75 m (capacity about 1.7 m³), sheet thickness - 4 mm (part of the sheet went 1.5 * 6 m);
- cast iron radiator - 7 sections;
- metal corner - welded around the perimeter of the upper part to fix the cover;
- rubber seal on a self-adhesive basis - to seal the same cover;
- metal fittings - fittings with external thread, shut-off valves;
- welding electrodes.
The process of assembling the container itself is simple - you need to:
- Boil all seams, clean, coat with a primer.
- Make holes for the pipes, install and scald the fittings.
- Weld "ties" inside the tank.
Heating elements are installed at the bottom - to heat the coldest layer
So that the walls do not "inflate" - Drill the corners in increments of 15-20 cm. These are the holes for the screed screws. then - strapping from the corner.
- Welding areas (all) should be cleaned, primed, painted.
- Prime and paint all surfaces inside and out.
- Clean, coat with a primer twice and paint the cast-iron battery / heat exchanger.
- Connect the battery to the conclusions made under the heat exchanger, fix it in the tank.
- Glue a rubber seal around the perimeter of the tank lid. It is better to glue the whole piece - it will be more airtight.
The finished tank is installed on a layer of high-density foam (10 cm), lined on the sides and top with a mineral wool mat 10 cm thick. The insulation was glued to the walls. During operation, the tank and components began to rust heavily. The magnesium anode installed inside helped to slow down the process.
Homemade sealed stainless steel tank
In a heating system with a coal-fired boiler with a capacity of 56 kW (heated area 190 m²), collected a heat accumulator with a volume of 4 cubes. Both the power of the boiler and the dimensions of the tank are taken with a very large margin - the owner wants to heat in the cold no more than 1 time per day, with a slight minus - once every two or three days. With these parameters, he succeeds. It is supposed to supply a coolant with a temperature not higher than 50 ° C to the system, so that the radiators in the rooms are installed with a double margin (). They stand on each radiator so that it is possible to regulate the temperature in each room separately. For a self-made heat accumulator, sheet stainless steel 2 mm thick was used.
Of the design features: homemade heat exchanger. It is also made of sheet metal. It consists of two plates, between which strips of metal are welded. These strips are guides for the flow of coolant. They do not reach one of the edges a little, they are located so that the flow goes in a "snake".
So "guides" for the flow of coolant from the boiler are welded
The size of the heat exchanger turned out to be large. To prevent the structure from walking, the cover, in addition to being scalded, was pulled over the area with studs, the installation sites were scalded with overlays from the same stainless steel. To check the tightness, a pressure test of 3.5 atm was carried out. Everything is intact, no leaks.
It is unlikely that questions will arise regarding welding of the hull itself. The only thing that might be interesting is that they cooked with an ordinary welding inverter, but with a TIG torch (purchased in a specialized store). An argon tank was also bought, so they cooked stainless steel in an argon environment.
A corner was scalded along the upper edge, studs were welded to the corner. They will be covered with a rubber seal.
Since the capacity is large, even dense foam will not withstand it. Therefore, a stand made of steel corner is welded under it.
All this is installed in the boiler room. The tank was covered on all sides with mineral wool 15 cm thick, OSB was sheathed over the insulation and painted. When finished, everything looks good.
According to the results of operation. In frosts of -25 ° C, it is necessary to heat once a day. At -7°C or -10°C - once every two days. With even warmer - and even less often.
How to make a buffer tank from a eurocube
If you decide to make a heat accumulator from a plastic container, be sure to pay attention to the temperature characteristics. Since the temperature of the coolant can reach 90 ° C, this should be the temperature that the plastic can withstand for a long time. There are few such European cubes and they are expensive. In principle, you can navigate by price. If the container is expensive, it may be suitable. Products made of low-pressure polyethylene (PE-HD) are characterized by high heat resistance. These containers are suitable for making a heat accumulator with your own hands.
It is easier to make a heat accumulator from an eurotank than from any other material. The container is ready, you just need to run the heat exchangers inside, cut through and insert functional devices and fittings. The main task is to carefully cut the holes - exactly under the fittings. Seal them with high-temperature sealants (non-acidic).
If you need to install heating elements from a Eurocube in a heat accumulator tank, it is better to cut out part of the wall, cut a plate from thick sheet aluminum. Pull the plate to the wall with bolts with paronite gaskets, carefully smearing everything with the same sealant.
Warming:
- sides - foil isol 5 mm. foil inside + 50 mm. EPPS
- top - 2 layers 10 mm. folgoizola + 50 mm XPS
- from below only 10 mm. folgoizol - a cube was placed on it during installation.
- The seams are additionally foamed. So EPP is safe.
Feedback from operation:
“Yesterday it got warmer to +2, so in the morning, at 7-00, it was 85 degrees, in TA, at 16-00 78 degrees, about 23-00, before turning on the heating elements - 75. As a result, the heating elements worked very little! But that's not always the case, sometimes it gets colder. Weather, wind, etc. - everything affects.
How to improve the efficiency of a solid fuel boiler? Reduce the cost of purchasing energy? Reduce the number of furnaces (the number of approaches for throwing / loading coal or firewood into the boiler) per day? The answer is to install a buffer capacity, the so-called. heat accumulator, and "charge" it with energy from the heat generator - heat the water in reserve. And then, as needed, spend it for the heating system. You can buy a heat accumulator ready-made - from the factory, or try to save money and make it yourself. We will talk about the successful implementation of homemade products in this article.
- How to make a heat accumulator for a solid fuel boiler from a tank.
- How to connect a buffer tank to a heating system with a solid fuel boiler.
- Experience in the use of a heat accumulator.
Homemade heat accumulator for a TT boiler from a tank from a fire engine
Sjava FORUMHOUSE user
We have expensive gas. Therefore, in addition to a 24 kW gas boiler, which I now heat the house with, I bought a solid fuel (TT) boiler with a capacity of 20 kW. Heated area - 135 sq. m. From it: 110 sq. m I heat with underfloor heating and another 25 sq. m radiators. TT boiler, after installation, paid off in almost a season. I believe that the installation of a heat accumulator (TA) will increase the efficiency of the heating system. In the off-season, with TA, I generally think of switching only to heating with a TT boiler and using a gas boiler as a reserve and for quick heating of the coolant. Then I plan to save even more - I will install a solar collector, and in the summer I will dump “free” energy from it into a buffer tank.
First, let's show the scheme of the heating system Sjava.
The circuit, after the commissioning of the heat accumulator, has undergone a slight change, which we will discuss below.
Now let's show how the user made a heat accumulator. The basis of the TA is a used barrel - a 1.5 cubic meter tank from a fire truck.
It is easier and cheaper to make a heat accumulator from a ready-made container than to cook a steel tank from zero on your own.
Important. If barrels / tanks from fuel and lubricants are used as a home-made container for TA(fuel and lubricants), then, in order to avoid accidents, because vapors retain flammability for many years, extra care must be taken when working especially welding.
V757V FORUMHOUSE user
I once got into a conversation with a fuel trucker, and he told me how they cook tanks at the oil depot. Pour water into the tank to the eyeballs. They put a raft with a burning candle at the top and slowly drain the water. Water gradually flows out, and everything that can burn quietly burns out as the container is emptied.
From the tank, measuring 2 (height) x 1.35 x 0.75 m, they cut off everything superfluous.
Because the heat accumulator is placed vertically so that the tank filled with water does not swell, the user made “ties” from a pipe with a diameter of 22 mm.
"Cables" are reinforced with washers, although, according to sjava, it's too much.
Pipe ties can be used as sleeves for installing thermometers or temperature sensors in TA.
The tank hatch is used as an inspection hatch and for inserting heating elements (tubular electric heaters) with built-in magnesium anodes 3 pcs. 2 or 3 kW.
The water in the TA will also be heated by electricity at a cheaper nightly rate.
Hatch details.
The bottom of the TA tank is reinforced with profile pipes with a section of 4x4 cm.
Welded pipes for tying TA with a boiler and a heating system.
The top of the TA is also reinforced, otherwise it will bulge from the pressure when the water is heated.
Welded homemade collector.
Couplings for heating elements are welded into the hatch.
The base for the TA is made of plywood and timber with a section of 100x100 mm with slots so that the pipes welded to the bottom of the tank do not press on the base.
The base for the heat accumulator is insulated with foam plastic.
In parallel with the manufacture of TA for the heating system, components came. thermostatic valve.
A circulation pump with taps, which will then be replaced with "American" ones.
Heating elements with magnesium anodes.
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Magnesium anodes protect TA metal from rust.
Cover seal Sjava made according to the original technology. First, the user sealed the cap with sealant. I screwed the cover on 16 bolts, but when testing the TA with a pressure of 2 bar, water began to ooze from under the roof. The do-it-yourselfer did not cut the rubber gasket. Too complicated, and there are no guarantees of tightness. Eventually Sjava made a silicone gasket.
Step by step instructions for making it:
- The place where the gasket is placed is painted, because silicone in contact with unprotected ferrous metal activates corrosion.
- With the help of hot glue, beads are glued around the circumference of the lid.
The inner collar is a piece of electrical cable, and the outer one is a packing tape.
Then the user, having previously calculated the volume of the gasket, took the cylinders with silicone, and filled the entire space between the shoulders, gradually smoothing the silicone with an old credit card.
The thickness of the gasket is 8 mm.
Sjava FORUMHOUSE user
I immediately warn you that silicone dries out for about a week. I removed the collars on the fourth day. When everything dried up, an elastic silicone mass was obtained. I drilled the holes later, at high speeds of the tool. The bolts enter with an interference fit, and when they are clamped with nuts, they additionally seal the junction. The budget of the engineering solution is 3 cylinders of sanitary silicone (2.5 cylinders actually took).
Rings (2 pcs.) for the lid are homemade, welded from two metal corners rolled around the circumference.
The assembly - tank-ring-lid-ring is first assembled on tacks and only then all the holes are drilled. This ensured high precision of mating parts.
Scheme of the neck of the heat accumulator cover.
So, a homemade heat accumulator is ready. Then the user proceeded to routine work - tying the HE with the boiler and connecting it to the heating system. And here's what happened.
Knots close up.
Schemes for connecting a buffer tank to a solid fuel boiler and a heating system
Topic Sjava aroused keen interest on the portal. Users began to discuss the scheme for connecting the TA to the boiler.
ZelGen FORUMHOUSE user
Looked at the scheme of the heating system. The question arose, why is the entrance to the TA located just above the middle of the tank? If the inlet is made from the top of the buffer tank, then the hot carrier from the TT boiler is immediately fed to the outlet, without mixing with the colder carrier in the TA. The container is gradually filled with hot coolant from top to bottom. And so, until the upper half of the TA warms up, which is approximately 500 liters, the hot carrier in the TA is mixed and cooled.
According to sjava, the input to the heat accumulator is made in such a way for better EC (natural circulation if the electricity is turned off) and to reduce unnecessary mixing of the coolant at a time when CO does not take heat or takes it away a little. Because the scheme of the heating system with TA laid out at the beginning is general, then the user sketched out more detailed options for the operation of the tank.
Advantages - if the light is turned off, then natural circulation works. The disadvantage is the inertia of the system.
An analogue of the first scheme, but if all thermal heads are closed in the heating system, then the upper part of the heat accumulator is the warmest and there is no intensive mixing. When the thermal heads are opened, the coolant is immediately supplied to the CO. This reduces inertia. There is also an EC.
The heat accumulator is placed parallel to the system. Advantages - fast supply of coolant, but natural circulation in the system is in doubt. Possible boiling of the coolant.
Development of the third scheme with closed thermal heads. The disadvantage is that there is a complete mixing of all layers of water in the heat accumulator, which is bad for natural circulation if there is no electricity.
This made it possible to change the connection scheme of the heat accumulator from parallel to serial. For example, the heating season has ended and the heat accumulator has cooled down, but it has become colder, then, without heating the heat accumulator, you can quickly heat the house with a boiler.
Operation of a heat accumulator with a solid fuel boiler: personal experience
The user's conclusions from the operation of the TA are interesting:
- The boiler enters the mode + 80-85 ° C in 10-15 minutes. As a result, there is no soot and smoke. After two or three furnaces, tar deposits and streaks from last year's condensate burned out. After two weeks of work in the optimal temperature regime, the boiler furnace became almost like new, now there is only ashes inside. Firewood in the boiler burns out completely, with maximum heat release, and the heat generator is not driven into smoldering mode.
If the coolant temperature is lowered below 60-65 °C, then conditions are created in the TTK combustion chamber for the appearance of condensate (harmful acids).
- A solid fuel boiler in tandem with a heat accumulator operates with maximum efficiency both in winter and in the off-season, at outdoor temperatures of 0 ° C - -5-10 ° C. Excess heat from a well-fired boiler is simply dumped into a heat accumulator, and then, as necessary, the coolant is consumed.
- Water in TA is "charged" in layers:
- Top - + 80 °C.
- Middle - + 65-70 °C.
- Lower part - +50-60 °C.
- When the boiler is not working, the water temperature in the lower part does not fall below the return temperature, and the top is gradually discharged. According to observations Sjava TA is “charged” to the above temperatures in 3-4 hours. If there is no frost on the street, and most of the underfloor heating branches are closed, then the heat removal to the CO decreases and the TA charge occurs faster.
- The thermostat is installed at the outlet of the flow from the heat accumulator to the heating system. At his command, if the water temperature drops to + 40 ° C, the gas boiler is turned on for reheating.
Sjava FORUMHOUSE user
With the blower fully open in the boiler, the temperature at the supply max + 90 °C. Usually the temperature is kept + 80-85 °C. The heat accumulator is charged in layers. First, the temperature of the top rises, and then the middle and bottom. For example, when the top is heated to the supply temperature, the temperature of the coolant in the middle of the heat exchanger starts to rise (the top remains 80-85 °C), then the temperature rises downwards.
The heat accumulator should be well insulated and placed vertically, because. hot water is concentrated at the top of the TA.
Questions arise, but is such a volume of TA enough for a house in cold weather? According to calculations Sjava for his cottage, at a temperature of -25 ° C, a heat accumulator of 5000 liters is needed. To quickly heat such a volume of water, a boiler with a capacity of 50-100 kW is required. But it is spent on an expensive system.