The efficiency of heating equipment is directly related to the heat output indicator. Comfort and coziness in a room heated by gas, wood or electricity depends on it. Therefore, it is important for the user to know what this physical quantity is and how it is calculated in each specific case.
Definition of the concept of heat power
The heat release power is understood as the amount of heat generated during the conversion of the original carrier into heating energy. This indicator is different in value for different types of energy carriers and is calculated for each of them individually. For gas boilers, it depends on the volume of natural or liquefied gas supplied to the burner per unit of time.
When considering electrical analogs, this parameter is directly related to the power of electricity consumed by the unit from the 220 or 380 Volt network and its thermal efficiency. The ratio of thermal and electrical power is set by special formulas that convert one value to another.
Required characteristics
Calculation of thermal power is very important, since its results are necessary to determine the parameters of the selected sample of heating equipment. The latter traditionally include:
- electrical power of the unit for volatile models;
- conversion efficiency (or boiler efficiency);
- productivity, defined as the amount of heat generated by the device per unit of time.
Models of boilers connected to the mains refer to equipment with the power consumption of the heating system, which is related to the amount of solid or gaseous fuel burned. For images independent of electricity, this parameter is determined directly - without recalculation for consumed electricity.
The efficiency of any heating unit to a large extent depends on the correct choice of the unit that ensures the conversion of thermal energy (heat exchanger). A competent solution to this issue allows you to obtain the required heat output and feel comfortable in the house even on the coldest days.
Excess thermal power is undesirable, since in this case, part of the funds spent is wasted.
Factors affecting heat demand
The main factors that determine the need for thermal energy for a room include:
- full volume of heated spaces;
- type and quality of insulation material;
- climatic zone in which the building is located.
The amount of air space that needs heating depends on the volume of the room. The larger the heated room, the more heat will be required to maintain the desired microclimate. With the same ceiling height (about 2.5 meters), a simplified calculation is usually used, in which the area of the room is taken as the basis.
The quality of insulation is judged by the way the walls are insulated, as well as by the area and the set of windows and doors. The type of glazing is also taken into account - a simple and triple glass unit are different in terms of heat loss.The influence of the climatic factor affects, other things being equal, and is taken into account as the difference in temperatures outside and in the room where the boiler is installed.
For the device (radiator)
When considering the factors affecting the heating power of heating radiators, there are three main ones:
- an indicator corresponding to the difference between the heating of the coolant and the surrounding air - with its increase, the thermal power increases;
- surface area that gives off heat;
- thermal conductivity of the material used.
In this case, the same linear dependence is observed: with an increase in the surface of the battery, the magnitude of the heat transfer also increases. For this reason, many modern heating radiators are supplemented with special aluminum fins, which increase the overall heat transfer.
Why do I need to calculate the power indicator
The need to determine the power is explained by the fact that the main characteristics of the boiler depend on the following factors:
- design features and purpose of the heated object;
- the size and shape of each room;
- total number of residents;
- location on the map of the country.
The calculated heat transfer power is used to determine the parameters of boiler equipment planned for installation in this particular room. The future boiler must have a capacity sufficient to heat it even on the coldest winter days. It is also important to provide for the possibility of coordinated connection of the unit to the main pipeline. The calculations carried out will help determine its length and size of pipes, as well as the type of radiators and parameters of the circulation pump.
Calculation of thermal power
In the estimated calculations, a special coefficient (efficiency) is also used, indicating the amount of consumed heat. It is found as the ratio of useful energy to the power of heat losses and is expressed as a percentage.
The amount of energy expended for premises depends on their construction features. The same indicator for batteries is determined by the materials used in their manufacture and design features.
More accurate thermal calculation
A competent choice of heating equipment is possible only after familiarization with the procedure for calculating the thermal power required in each specific case. The formula used to determine it exactly looks like this: P = V∆TK = kcal / hour:
- V - the volume of the heated room, measured in cubic meters.
- ∆Т - the difference between the air temperature outside and inside the room.
- TO - coefficient of heat loss.
The latter value depends on the material of the walls. On the basis of measurements carried out by specialists for a non-insulated wooden structure, it is 3.0-4.0. Exact values TO for different insulation options are given below:
- For buildings made of single brickwork and with simplified structures of windows and roofs (the so-called "simple" thermal insulation) K = 2.0-2.9.
- Insulation of average quality (K = 1.0-1.9). This is a typical construction, which means double masonry, a roof with a conventional roof, a limited number of windows.
- High-quality insulation (K = 0.6-0.9), assuming brick walls with reinforced thermal insulation, a small number of double-framed windows, a solid floor base and a roof with reliable thermal insulators.
As an example, the exact calculation of power for a heated room with a volume of 5 x 16 x 2.5 = 200 cubic meters will be considered. ∆Т is defined as the difference between the indicator outside -20 ° С and inside the room +25 ° С. An option with an average specific thermal insulation (K = 1-1.9) is accepted. For average operating conditions, we take 1.7.We calculate: 200 x 45 x 1.7 = 15 300 kcal / hour. Based on the fact that 1 kW = 860 kcal / hour, in the end we have: 15 300 \ 860 = 17.8 kW.
