To install or not to install a buffer tank when installing a solid fuel boiler
The use of a conventional "hardtop" without pellet burner and without a buffer, it is extremely dangerous and economically unprofitable, since in the smoldering mode, the efficiency of a solid fuel rapidly drops, and this is especially true for boilers with afterburning of combustion products!
Consider the features of "solid tops"
Everything solid fuel boilers, regardless of their type and method of fuel combustion, have the following common features:
- They work only in a narrow high-temperature schedule (90/75 0С or 80/600С).
- They can change the power in the range 100…50% by reducing the amount of incoming air during combustion. Moreover, with a decrease in power, the efficiency drops sharply due to an increase in the proportion of CO.
- The boiler cannot be stopped until all the fuel in it has burned out.
- A manually loaded boiler is selected with a power reserve of at least 30% for the coldest five-day period for residential premises and up to 50% for office buildings, since a significant problem with the quality and humidity of the fuel may arise, which must be taken into account.
Modern heating systems, depending on the outside temperature and indoor climate, change the flow and temperature in the heating devices. Thus, when installing a solid fuel boiler in a heating system, a dilemma arises: the boiler works most economically in high-temperature mode, and the heating system in low-temperature mode.
Buffer capacity solves this dilemma. It allows the solid fuel boiler to burn fuel with maximum efficiency and store it in a buffer tank with little loss. And the heating system takes away the accumulated heat in clearly calculated portions according to its need and depending on the heat loss of the building.
It was also noticed that systems with solid fuel boilers that do not have a buffer capacity have a fuel consumption 2-2.5 times higher than systems with a buffer capacity. This is due to the fact that most of the time during the heating season the weather is relatively warm, which means that the boiler is constantly operating with a lack of combustion air, and more than half of the fuel literally flies into the pipe in the form of CO (undercooking).
Highest efficiency in solid fuel boiler at the moment when it is above the return dew point (usually 51 degrees), but has not yet reached the set temperature set on the controller! As soon as the solid fuel boiler reaches the set temperature and goes into smoldering, the boiler efficiency drops down to 20%, thereby offsetting all the savings.
In addition to saving fuel, the buffer tank allows you to significantly reduce the number of fuel loadings during the day. The estimated volume of the tank depends on the boiler power, fuel load and burning time per load and what you want from the buffer tank (accumulation of unused energy). It is recommended from a minimum of 25 liters (this volume is usually set to protect against boiling and cannot properly accumulate energy in sufficient volume) to optimal 55 liters per kW of boiler power.
And as a result, we get a pellet automatic boiler house much cheaper than a boiler house with manual fuel loading, no matter how paradoxical it sounds, both in the cost of equipment and in the price of fuel, which is usually lower than the cost of labor of stokers!
Experience in installing and piping a solid fuel boiler with a buffer tank
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