The main criterion for choosing a device for heating a room is heat transfer - a coefficient showing the amount of heat released to the surrounding air by the heating device. In other words, the higher this indicator, the faster and better the heating of the house will be carried out. In this article, we consider the types and heat dissipation of heating radiators, the table will serve as a visual demonstration.
Indicator calculation
For an accurate calculation of the required amount of heat for the room, many factors should be taken into account: the climatic features of the area, the cubic capacity of the building, possible heat loss of the walls, ceiling and floor (the number of windows and doors, building material, the presence of insulation, etc.). The heat transfer parameters of heating radiators in the table below.
This system of calculations is rather laborious and is used in rare cases. Basically, the calculation of heat is determined on the basis of established approximate coefficients: for a room with ceilings not exceeding 3 meters per 10 m 2 , 1 kW of thermal energy is required. For the northern regions, the indicator increases to 1.3 kW.
Cast Iron Radiators: Features
Radiators made of cast iron vary in height, depth and width, depending on the number of sections in the assembly. Each section can have one or two channels.
The larger the area to be heated, the wider the battery will be needed, the more sections there will be in its composition and the greater the heat transfer required. For cast-iron heating radiators (the table will be given below), this figure is the highest. It should also be borne in mind that the number and size of window openings and the thickness of the walls in contact with the outside air will affect the indoor temperature.
The height of the radiator can range from 35 centimeters to a maximum of one and a half meters, and depth - from half a meter to one and a half. The batteries from this metal are quite heavy (about six kilograms is the weight of one section), therefore, strong mounts are required to install them. There are modern models that are produced on legs.
For such radiators, the quality of the water does not matter, and from the inside they do not rust. Their working pressure is about nine to twelve atmospheres, and sometimes more. With proper care (draining and flushing) can last quite a while.
In comparison with other competitors that have appeared recently, the price of cast-iron radiators is the most favorable.
The heat transfer table of cast-iron heating radiators is presented below.
Parameters of bimetallic radiators
The technical parameters of bimetallic radiators are determined by the specifics of their design - a rod made of anticorrosion steel in contact with the coolant is located in a lightweight aluminum casing. Such a symbiosis of materials gives them corrosion resistance, high heat transfer and low weight, which facilitates the installation process.
Of the minuses, high cost and low bandwidth can be noted.
There are also semi-metallic models in which steel serves as a reinforcement of vertical tubes. In such batteries, aluminum comes into contact with water and corrodes. The service life in this case is reduced, but they are also cheaper.
Based on the foregoing, semi-bimetal radiators can be used for private houses with individual heating, but only bimetallic ones can withstand the aggressive water environment of central heating.
Structurally, these types of heating appliances are divided into monolithic and sectional. The first two times superior to the second type in terms of service life and three times - in terms of working pressure. And as a result, at a cost.
The heat transfer table of bimetallic radiators is further.
Characteristics of aluminum batteries
Radiators made of aluminum are characterized by the fact that their outer side is covered with a powder layer that is resistant to external corrosion, and the inside with a polymer protective coating.
They have a neat appearance, light in weight, belong to the middle price category.
The heating method for aluminum radiators is convection, they withstand pressure up to sixteen atmospheres.
Structurally, this type of device is divided into extruded and cast. In the first case, the production process consists of two stages: first, ductile aluminum is extruded into sections, and the top and bottom are cast under pressure, and then the components are glued together with a special composition. In the second case, the entire section is immediately cast under pressure. This method makes the structure more robust, allowing it to more stably withstand the water shocks that occur during pressure testing of heating systems before the onset of winter.
The following are the heat transfer characteristics of aluminum heating radiators in the table.
Steel radiators
Steel heating appliances are on the market in a wide range. Structurally, they are divided into panel and tubular.
In the first case, the panel is mounted on a wall or on the floor. Each part consists of two welded plates with a coolant circulating between them. All elements are connected by spot welding. This design significantly increases heat transfer. To increase this indicator, several panels are connected together, but in this case the battery becomes very heavy - a radiator of three panels is equal in weight to a cast iron one.
In the second case, the design is the lower and upper collectors connected to each other by vertical tubes. One such element may contain a maximum of six tubes. To increase the surface of the radiator, several sections can be joined together.
Both types are durable, with good heat dissipation heating devices.
For design purposes, tubular steel radiators can be produced in the form of partitions, stair railings, mirror frames.
The heat transfer table of steel heating radiators is available later in the article.
Types of connection of radiators
The heat dissipation of batteries depends not only on the material from which they are made. Of great importance is the type of connection to the pipes of receipt and removal of heating. The radiator can be connected:
- Diagonal way. In this case, the supply pipe is connected to the top left, and the branch - to the bottom right. This type is the most effective, because it allows you to evenly warm the entire battery for good heat transfer. Old cast-iron heating radiators (parameter table above) were connected in this way.
- One way (side connection). In this case, the pipes are connected on one side. This type of connection is considered less effective - if there are many sections in the radiator, then they cannot warm up sufficiently.
- Bottom connection - both pipes are connected from below on both sides.
- Top connection. In this type of pipe are connected from above: the supply on the left, the outlet on the right.
Comparison of radiators for heat transfer: table
Below is a comparative table of the heat transfer of batteries made from various materials. She will help to orient in the market of these devices.
You only need to remember that for effective heating of the room you need to not only choose the type of radiator and its connection, but also calculate the length of the device (number of sections) depending on the heated area.
The comparison table is as follows.
Ways to increase heat transfer
The convector characteristics indicated in the data sheet are those subject to ideal conditions, the heat transfer parameters of heating radiators in the table also correspond to this. Unfortunately, at the household level this is not possible.
Actually, the heat flux of the radiator is slightly lower, and heat loss also occurs due to many factors. And among them, the one that the standard parameters are indicated for the inlet temperature of clean water is about seventy degrees Celsius, but in fact, the consumer already gets a polluted stream of 50-60 degrees heat.
To increase the heat transfer parameter, experts advise:
- Warming. To keep more heat in the room, it is necessary to insulate it. In apartments and houses, this can be done both outside and inside. For these purposes, special foam panels are used: two to five centimeter thick for the exterior, half a centimeter for the inside. It is also necessary to insulate the roof.
- Reflector installation. Reflective material (usually foamed polypropylene on one side) is mounted on the wall behind the radiator and serves to reflect infrared radiation, which increases the heat transfer of heating radiators (the table above shows data for this parameter).
- Tightness. Drafts in the room significantly reduce the amount of warm air. Warming will be much more effective if you pay attention to windows and doors, ensuring only the authorized flow of air masses.
In any case, no matter what type of radiators are installed, you need to carefully study the characteristics of the devices and invite a specialist for their installation.