Storage tank for heating boilers

No possibility to use as an energy source for home heating relatively inexpensive natural gas is forcing the owners of houses to find other acceptable solutions.For example, in regions where there are no special problems with the workpiece or the purchase of firewood to the aid of solid fuel boilers.It happens so that the only alternative becomes electrical energy.In addition, the increasingly used new technology to be sent to the heating needs of the solar energy.

All of these approaches are not without drawbacks.For example, they include the unevenness expressed by the frequency of the thermal energy input.In the case of electric boiler main negative factor is the high cost of energy consumed.Obviously, to significantly raise the heating efficiency, improve efficiency, uniformity of its work, to simplify maintenance operations to help in the general scheme including a special device, which would accumulate in the unclaimed current thermal energy and release it as required.It is this function is performed by heat accumulator for heating boilers.

The main purpose of the storage tank heating system

• simplest heating with solid fuel boiler has a pronounced cyclical operation.After loading the wood and ignition, the boiler is gradually emerging at the maximum power, actively transmitting heat to the heating circuits.But as the burning heat load starts to decrease gradually, and coolant that passeth by radiators, cooling down.

It turns out that during the peak heat generation, it may remain unclaimed, as configured, equipped with thermostatically controlled heating system excess will not take.But during the fuel has burnt out, and the more idle thermal power boiler is clearly lacking.As a result, the capacity of the fuel is consumed just wasted, but the owners have to frequently deal with loading firewood.

a certain extent of the problem can be reduced by installing a long burning boiler, but completely removed - it is impossible.The discrepancy between the peak heat generation and consumption can be quite substantial.

• In the case of electric boiler to the fore the high cost of energy consumption, which makes owners think about the maximum use of the equipment during the term of preferential tariffs and night to minimize consumption in the daytime.

benefits of using a differentiated charging

electricity With the right approach to the consumption of electricity feed-in tariffs could bring very tangible savings.This is described in detail in a special publication portal dedicated two-tariff electricity meters .

begs the obvious solution - to accumulate heat at night to reach the minimum consumption of its day.

• Even more pronounced periodicity of heat generation in the case of the use of solar collectors.There can be traced not only dependent on time of day (delivery generally zero at night).

defies comparison heating peaks in bright sunny day or in cloudy weather.It is understood that directly raise your heating system depending on the current "whims" of nature - can not be, but neglect such a powerful additional source of energy is also not desirable.Clearly, what is required for a buffer device.

These three examples, in spite of their diverse, united by one common factor - the apparent discrepancy between the peak heat generation with its uniform rational use for heating.To address this imbalance, and serves as a special instrument, called accumulator tank (heat storage, buffer capacity).

principle of its operation is based on a high heat capacity of water.If a significant amount of its revenues in the period of peak heat energy to warm up to the required level, then for a certain period can be used for heating the accumulated energy potential.For example, when compared to thermal indicators, that only one liter of water under cooling at 1 ° C is able to heat the air as much as a cubic meter 4 ° C.

heat accumulator is always a bulk tank with an effective external thermal insulation, connected to the circuit (s) of the heat source and heating circuits.The simplest scheme is better to consider the example:

easiest on the thermal receiver design (TA) - a vertically arranged bulk tank, in which two opposite sides are cut four pipe.On the one hand it is connected to the contour of solid fuel boilers (LHP), and on the other - for breeding at the house heating circuit.

After loading and firing of the boiler circulating pump (Nk) of the circuit begins to pump the coolant (water) through the heat exchanger.From the bottom of the boiler TA enters the water cooled down and arrives at the top heated by a boiler.Because of the significant difference density cooled and hot water it will not be active mixing in the tank - a fuel in the combustion process bookmarks will be a gradual filling of TA hot coolant.As a result, with proper sizing, after the complete burning of the pledged fuel container is filled with hot water, heated to the calculated level.All the potential energy of the fuel (excluding, of course, the inevitable losses in boiler efficiency) is converted into heat, which is accumulated in the TA.High-quality thermal insulation allows you to store the temperature in the tank for hours, and sometimes - and days.

second stage - the boiler is not working, but the heating system functions.With the help of its own circulation pump heating circuit occurs pumping coolant through the pipes and radiators.The fence is made from the top, from the "hot" areas.Intensive self-stirring again not observed - for the reasons already mentioned, and in the supply pipe enters the hot water, the bottom is returned chilled and tank gradually gives his heat in the upward direction.

In practice, in the boiler furnace in the selection of the coolant heating system typically does not stop, and a TA will accumulate excess energy, which currently remains unclaimed.But with the right sizing of the buffer tank, or one kilowatt of thermal energy should not have the gift of the abyss, and by the end of the boiler furnace cycle TA should be to the maximum extent "charged".

clear that the cyclical nature of the work of such a system with installed electric boiler will be tied to preferential rates at night.The timer control unit turns on or off the power at a given time in the evening and in the morning, and during the day the heating circuits will only eat (or mostly) from the storage tank.

Features and main circuits connecting various storage tank

So heat accumulator is always a bulk tank vertical cylindrical execution, has a highly efficient thermal insulation and fitted with connections for connecting the heat generation circuit and its consumption.But the internal structure can vary.Consider the main types of existing models.

main types of storage tank designs

1 - easiest type of TA design.It is understood the direct connection and heat sources and consumption circuits.These buffer tanks are used in the following cases:

• If the boiler and all heating circuits are using the same coolant.
• If maximum coolant pressure in the heating circuit does not exceed that of the boiler and of the General Assembly.

In the case where the claim can not be made, connect the heating circuits can be carried out via an external heat exchanger

• If the temperature in the pipe flow at the outlet of the boiler does not exceed the permissible temperature of the heating circuits.

However, this requirement may be bypassed when installed on circuits that require a low temperature difference, mixing units with three-way valves.

2 - storage tank is equipped with an internal heat exchanger located in the bottom of the tank.The heat exchanger is usually a spiral, a retinue of stainless steel tubes, normal or corrugated.There may be several heat exchangers.

This type of TA is used in the following cases:

• If pressure and coolant temperature achieved in the heat source circuit is significantly higher than the permissible values ​​for consumption circuit and buffer tank itself.
• If there is a need to connect multiple sources of heat (for the principle of dual mode).For example, come to the aid of the boiler The solar (solar collector) or a geothermal heat pump.The lower the temperature difference of the heat source, the following must be located in its TA exchanger.
• If a different type of coolant used in the heat source circuits and consumption.

Unlike the first scheme, such a characteristic TA active mixing of the coolant in the tank - heating occurs in the lower part, and the less dense warm water aspires upwards.

Scheme for Aviation Center shows a magnesium anode.Due to a lower electric potential, he "pulls" the heavy salt ions, preventing overgrowth scum internal walls of the tank.Subject to periodic replacement.

3 - storage tank is supplemented hot water flow path.Cold water inlet from below, to the point of supply of hot water pumping, respectively, below.Most of the heat exchanger located in the upper part of the TA.

This scheme is considered to be the optimum conditions for when hot water is different sufficient stability and uniformity, without pronounced peak.Naturally, the heat exchanger must be filled with metal that meets the standards of water consumption of the food.

The rest of the descent of the first circuit, with direct connection of heat generation and consumption circuits.

4 - inside the heat storage tank is placed to create a reserve of hot water for domestic consumption.In fact, this arrangement recalls the built indirect heating boiler.

Application of such a construction are fully justified in cases where the heat generation peak boiler does not coincide with the peak consumption of hot water.In other words, when prevailing in the home consumer lifestyle involves mass, but rather a short consumption of hot water.

All these schemes can vary in different combinations - the choice of a particular model depends on the complexity created by the heating system, the number and type of the body of sources and consumption circuits.Note that in most storage tank, a plurality of output nozzles spaced vertically.

fact that when any circuit within the buffer tank somehow produced a temperature gradient (difference in temperature difference in height).There is an opportunity to connect the heating circuits that require different temperature regimes.This greatly facilitates the final thermostatic control of heat exchangers (radiators or "warm floor"), with a minimum of unnecessary loss of energy and reduce the load on control devices.

Typical connection diagrams storage tank

Now you can see the basic installation scheme storage tank to the heating system.

Illustration	Brief description of the circuit
	Temperature and pressure are the same in the boiler and the heating circuits. to the coolant requirements are the same. On leaving the boiler and in a constant temperature TA. on heat exchange devices control is limited only by the quantitative change of coolant flowing through them.
	in connection to the storage tank, in principle, repeats the first scheme, but the adjustment of operating modes of heat exchangers is carried out on the principle of quality - with a change in temperature of the coolant.For this circuit included in the thermostatic mixing units, such as three-way valves. This scheme allows the most efficient use of accumulated accumulator tank capacity, that is, his "charge" will last for a longer time.
	Such a scheme, with a circulation of coolant in the small loop of the boiler via the built heat exchanger is used when the pressure in this circuit exceeds the allowable heating devices or in a buffer tank itself. The second option - the boiler and the heating circuits of different coolants used.
	starting conditions are similar scheme №3, but applied an external heat exchanger. Possible reasons for this approach: - heat exchange area embedded "coil" is not enough to maintain the desired temperature in teloakkumulyatore. - had already been purchased by TA without internal teplobmennika and upgrading heating systems require such an approach.
	scheme with the organization to ensure the flow of hot water through the built-in spiral heat exchanger. calculated on a uniform, hot water, without the peak.
	This scheme, with storage tank with built-in tank, designed for a peak hot water, but it is not very positive. After spending created a stock and, accordingly, fill the tank with cold water, heated to the desired temperature can take a lot of time.
	bivalent system makes it possible to use the heating system an additional source of thermal energy.