When the room is cold when the central heating batteries are running, many people turn on additional heaters, but rarely does anyone think about how to increase the heat output of central heating radiators. If turning on heaters is a temporary and very expensive measure, then increasing the efficiency of batteries is a long-term solution to the problem of a cold room, which often does not require additional investments. This article will show simple and complex ways to effectively increase the heat transfer of batteries.

What affects the efficiency of central heating radiators?

1. The temperature of the coolant in the system;
2. The speed of movement of the coolant;
3. Type of connection to the heating system;
4. The material from which the radiator is made;
5. Heat transfer area and number of radiator sections.

An important role is played by other factors that appear during the operation of radiators. So, for example, the heat transfer of batteries will decrease if:

• Apply many layers of paint;
• Do not dust;
• Periodically do not bleed air from the radiators;
• The internal cavity, filters and nozzles are clogged;
• The radiator is covered with a decorative screen, curtains, furniture, etc.

In general, disturbed air convection (the last point) is one of the main conditions for poor heat transfer from central heating radiators. It is necessary to direct all efforts to eliminate this problem first.

Simple ways to increase the heat transfer of radiators

. Batteries transfer heat to the air, which, when heated, rises, and then, cools, falls down. This is how air circulates, and the room becomes warm as much as the heat transfer of the battery and the speed of the air flow allow. Therefore, in order to increase the temperature inside the room, first of all, it is necessary to ensure good air circulation. To do this, free up the space around the battery to the maximum: remove the protective screen, raise the curtains, move the furniture, and so on.

Speed ​​up air circulation with a fan. The faster the air moves, the more heat energy it can take from the battery. On the coldest days, you can turn on the fan, directing it to the center of the battery to capture as much area as possible. To ensure the autonomy of such a system and ensure its quiet operation, you can place computer fans. They are quiet, low power, and when placed directly under the battery do not disturb the natural direction of air movement in the room. Fans will allow you to raise the temperature in the room by 3-10 degrees, and their low consumption makes it possible to blow the battery all year round without significant damage to your wallet. Calculate for yourself: the power of ordinary fans is about 40 watts, computer fans - no more than 5. Total consumption: 40 * 24 (hours) * 30 (days) \u003d 29 Kilowatts \u003d about 95 rubles per month. In the case of computers, even less - about 23 rubles per month. when connecting 2 at once.

Installing a heat shield. The heat from the battery radiates in all directions, and in order not to heat the walls, but to direct the heat energy into the room, you need to install a heat-reflecting screen behind the battery. For these purposes, you can use foil isolon (foamed base with foil on one side), gluing it to the cleaned wall behind the battery with any suitable means (tile glue, universal glue 88, silicone, etc.). Ideally, the area of ​​the heat-reflecting screen should be larger than the area of ​​the battery.

If the battery at the top is cold need to let the air out. To do this, unscrew the usual or Mayevsky tap at the top of the battery.

It will not be superfluous to keep a container or a towel under the valve, because as soon as the air comes out, water will flow in a thin stream. Once this happens, the valve can be closed. The procedure should be repeated for each battery in the house.

Sophisticated ways to increase the heat transfer of radiators

If the previous methods did not help, or their use causes significant discomfort, you can solve the problem in one of the cardinal ways:

• Change heating radiators (below is a table of thermal conductivity and thermal power of radiators);
• Increase the number of battery sections (more battery area - warmer in the room);
• Clean the internal cavity of the radiator from dirt, corrosion, scale;
• Change the type of connection (optimal - straight diagonal or straight one-sided);

It is required to carry out all these works with the heating system turned off, which in most cases is difficult during the heating season. However, the situation will be greatly facilitated if shut-off valves are installed at the inlet and outlet, which makes it possible to disconnect each radiator individually from the heat supply network.

Table #1: Thermal Conductivity of Metals

Table 2: Heat output of radiators

The best option is bimetallic radiators, which are not demanding on the quality of water in the heating system and at the same time have a high heat output. This was achieved through a combination of steel (inside) and aluminum (outside), as well as thanks to modern technologies that made it possible to achieve a large heat transfer area, with relatively oversized sections.

Properly using the resources of central heating, you can forever save yourself from the need to connect additional heating devices. And, knowing how to increase the heat transfer of batteries, you can adjust the temperature in the room at your discretion.

The funny thing about heating radiators is that they are not actually radiators at all. The fact is that the term "radiator" is a little inappropriate for a device that heats a room. The word radiator comes from the English word “radiate”, which translates as to radiate. But radiators don't actually radiate heat, they heat the room by convection.

So what is it then?

Regardless of the material of radiators and their design, the vast majority of radiators radiate about 80% of the heat produced by convection, as a result, only 20% remains for thermal radiation. Don't worry, there's nothing wrong with this ratio. Some experts mistakenly believe that this ratio is 50/50.

Radiators were invented by Russian businessman San Galli, although some people still dispute his invention.

He called them "hot boxes", which is a fairly accurate description of a radiator. A warm box that moves air around it and raises the temperature in the room.

In the USA they are called - heaters. It is worth noting that Americans use a more accurate term derived from the word “heaters”. After all, this is exactly what radiators do - they heat and give off heat.

The scientist will refer to heat as thermal energy that can move in space by conduction, convection or radiation. Your home is mounted on the wall under the window - it heats the cold air above it, and with the help of the slightest drafts from the window, convection currents move the heat around the room.

How does a radiator heat a room?

Convection currents are created when the air above a heatsink heats up, then cools down, and then heats up again. This process takes place continuously as long as you have the heating on. In this way, radiators move heat around the room, which makes the house warm and cozy. To put it scientifically, heat is created due to the transition of potential energy into kinetic energy.

When a heating radiator heats up the air, it causes the atoms to vibrate at a high frequency. The atoms continue to vibrate faster and faster, resulting in the creation of thermal energy. This process is known as convection.

No matter how Oddly, the term “radiator” is much better suited to underfloor heating. Because this system actually radiates heat throughout the room. More than half of the heat generated is produced through radiation.

Get the most out of your radiator

Given that the radiator is working to create those beautiful convection currents while you're watching football, it's worth making sure the heat stays inside the house. This will save energy, money and heat. Thermal energy, like Houdini, likes to disappear unnoticed.

It can go through the roof, windows, walls and any small gap invisible to the human eye. Are your poor ones (or hot boxes ☺) working so hard while you let the heat out of the house? Do not do this!

Install attic insulation, insulate wall cavities, and make sure windows are in good condition. This will keep the atoms inside the room and prevent them from escaping into the street, taking precious degrees of heat with them.

How does a radiator heat a room? was last modified: April 10th, 2017 by jennifer thompson

The question of choosing a suitable radiator for heating a house or apartment plays an important role. After all, safety, the possibility of saving on energy resources, compliance with interior design, warmth, and hence the feeling of comfort in housing depend on this. To answer the question, for central heating, you first need to establish the technical characteristics and features of each type of modern batteries.

Choosing a heating radiator is necessary considering many factors.

When purchasing a radiator, the following aspects are of no small importance:

• Efficiency of functioning, that is, the ability to heat the room.
• Safety and durability.
• Availability in terms of price.

Also, the choice of heating radiators is largely determined by the system in which they will be installed - central or autonomous.

The centralized system used in apartment buildings has the following features:

1. Typically, the operating pressure in this system when supplied is in the region of 4-5 kgf / cm 2 and slightly less at the outlet. In private homes, the maximum pressure is only 2 kgf / cm 2.
2. In central systems, the probability of unforeseen circumstances associated with water hammer, the use of heat carriers with a temperature above the permissible level, etc. is much higher.

The technical characteristics of the heating system, which are determined by:

• Working pressure.
  The basic rule: the pressure of heating batteries is greater than in the room in which they are installed. Otherwise, a leak will soon appear. The technical characteristics of the heating system, which are determined by:
• The type of heating system is one- or two-pipe.
• Radiator power. The most important value, which indicates the efficiency of heat transfer from the source to the consumer, that is, how well the radiator heats the house. The power indicator is influenced by the presence of windows and the material from which they are made (wood or plastic), the type of house (panel or brick), the number of external walls, and the area of ​​\u200b\u200bthe room. The value required is determined by multiplying the area of ​​​​the room by 100 W and increases by a certain percentage depending on various factors:
  • in the presence of 2 external walls and 2 windows - by 30%;
  • when the windows go to the north side - by 10%.

• Radiator sizes. The device must correspond in size to the place intended for installation. The optimal distance between the window and the radiator is from 10 cm or more, the floor and the radiator - from 6 cm. The width of the radiator should exceed 50% of the width of the window under which it is installed.

The main types of radiators have the following characteristics:

Also, do not forget about such nuances as the presence of a thermostat, pipe diameter, window width.

The main types of radiators for central heating, their disadvantages and advantages

Cast iron radiators. The leading type of radiators in terms of prevalence for several decades. Only the appearance has changed significantly - there are models that are real design samples (their cost is appropriate). Good for use in residential and industrial high-rise buildings.

Advantages:

• high heat transfer;
• strength and durability;
• unpretentiousness and endurance;
• large flow area, allowing you to maintain the throughput even with the accumulation of deposits.

Disadvantages:

• the need for washing 2-3 times a year;
• vulnerability to strong mechanical stress (the battery may crack);
• high price.

aluminum radiators. Currently enjoys great popularity among Russians. They consist of sections, the number of which depends on the area of ​​\u200b\u200bthe heated room. It is this type that is characterized by the highest degree of heating, achieved due to the high thermal conductivity of the metal itself and an increase in the thermal conductivity area, thanks to the developed finning system. According to the design, sectional and solid models are distinguished.

Aluminum radiators are not recommended for centralized heating systems. Since, in the presence of oxygen in the coolant, this metal is oxidized, and the sections are “aired” due to the release of hydrogen. To avoid this, the device requires regular maintenance and evacuation of air.

Advantages:

• ease;
• external attractiveness;
• strength and reliability;
• excellent heat dissipation.

Disadvantages:

• susceptibility to corrosion;
• the need to regularly bleed air from the radiator through the air vent valve;
• deformation of aluminum during water hammer;
• solid particles present in coolants contribute to the destruction of the walls of the device from the inside, which reduces the life of the device (this problem is solved by equipping the radiator with mud collectors and additional filters that require regular cleaning);
• when connecting aluminum pipes with copper, the rapid destruction of aluminum.

Steel radiators. A common view in the conditions of low-rise private construction. Not the best option for centralized heating, because:

• usually the working pressure in the heating system exceeds the allowable one;
• with hydraulic shock, the service life is significantly reduced and is only a few months.

Advantages:

• attractive design;
• occupation of a small space in the room.

Disadvantages:

• susceptibility to corrosion;
• average service life at observance of operational rules - no more than 7 years.

Bimetal radiators. They combine the advantages of the two previous types of radiators, due to the special design - an aluminum shell and a steel core. They are used for any type of heating, but they have proven themselves especially well in high-rise buildings with central heating.

Advantages:

• the ability to withstand significant loads and hydraulic shocks, strength;
• high heat transfer;
• light weight and thoughtful shape, contributing to the efficient heating of the room.

Disadvantages:

• high price due to the complexity of the design.

findings

So, it is not possible to give an unambiguous answer to the question of which heating radiators are best for central heating, since each specific situation is individual and the choice depends on the characteristics of housing conditions and the price range. But in general, the opinions of experts boil down to the following:

1. Due to the unpredictability of central heating, the best at the moment are those that combine mechanical strength, high heat transfer and aesthetic appearance. The main disadvantage is the high cost.
2. Cast iron radiators also deserve attention, but require more maintenance.
3. It is better to refuse steel and aluminum radiators in houses with central heating, due to the characteristics of these metals - susceptibility to corrosion, interaction with other metals, etc.

The main task of the batteries is the efficient heating of the room. The key characteristic of the high-quality operation of the heating system is heat transfer, which expresses the amount of heat transferred over a certain amount of time. The heat transfer of heating radiators depends on many nuances, the details of which will be discussed below.

Heat transfer is a key characteristic of the high-quality operation of the heating system

What you need to know about heat dissipation

Radiator power, thermal ceiling, thermal power - all these concepts are identical to thermal output, the unit of which is Watt. Sometimes the heat ceiling is also measured in calories. This value can be converted to Watts: 1 W equals approximately 860 calories per hour.

Heat transfer is produced by several processes:

• heat exchange;
• convection;
• radiation.

All three methods of heat transfer are carried out in the battery, but their specific proportions vary depending on the type of heating equipment. Radiators may include devices in which at least a quarter of the heat is released in the form of direct radiation. However, it must be replaced that today the boundaries of this requirement have been somewhat erased, since convector devices have also begun to be called radiators.

Calculation of the required heat output

The choice of batteries should be based on the most correct calculations of the required power. On the one hand, extra sections are useless, but on the other hand, a lack of power will make it impossible to achieve the desired temperature.

The heating efficiency is affected by the characteristics of the room. Among them:

• room area;
• ceiling height;
• location of the premises (on the corner or not);
• floor;
• the number of external walls and windows;
• characteristics of installed windows;
• the presence of insulation on the outer walls;
• the presence of additional heat sources in the room;
• the presence of an attic space and the quality of its insulation.

There are several methods for calculating the need for heating system power. The easiest way is based on taking into account the number of windows and walls bordering the street. The calculation is done like this:

The easiest way to calculate the power of a heating system is to count the number of windows and walls bordering the street

• in a standard situation (one window, one external wall), you will need 1 kW of heat output for every 10 square meters of the room;
• if there are two windows or two external walls in the room, a correction factor of 1.3 is applied (in other words, 1.3 kW of thermal power is needed for every 10 square meters).

The next method is a little more complicated, but it allows you to get more accurate indicators of the required power, since one of the parameters used is the height of the room.

The formula is used to calculate:

Power \u003d room area x room height x 41 (according to the regulations - the minimum power per cubic meter of the room).

The result obtained is the required thermal power. To determine the number of sections needed, we divide this result by the heat output of one section (indicated in the battery data sheet).

Advice! As a result of calculations, a fractional number can be obtained. In this case, the number must be rounded up.

Heat dissipation and battery material

From the point of view of structural materials, there are four main types of radiators: cast iron, steel, aluminum and bimetallic. In each case, the heat transfer is different.

Cast iron batteries

Such radiators are characterized by an insignificant heat transfer surface, as well as low thermal conductivity. The heat transfer of cast-iron radiators is carried out primarily by radiation, and only a fifth of it falls on convection.

Each section of the cast iron battery has a rated power of 180 watts. Although such indicators are achieved only in laboratory tests. If we are talking about central heating systems, the coolant only occasionally warms up above 80 degrees, and part of the thermal energy is lost even on the way to the radiator. As a result, the real heat transfer is fixed at the level of 50-60 W.

Steel Batteries

Steel radiators consist of one or more panels, between which there are so-called ribs that act as a convector. The thermal output of steel devices is only slightly higher than that of cast iron ones. Therefore, their main advantage is low weight and more aesthetic design.

If the temperature of the coolant decreases, the heat output of the steel battery drops sharply. In this regard, the actual characteristics of the radiator may differ greatly from those indicated by the manufacturer.

The heat transfer of aluminum radiators is higher than that of steel and cast iron devices (up to 200 W per section). However, there is a limiter to the use of aluminum in the heating system - the tendency to corrosion. Aluminum is very sensitive to the quality of the coolant, so it is better to install such radiators in private homes.

Bimetallic batteries

In terms of heat transfer efficiency, this type of radiators is no worse than aluminum ones. In some cases, it exceeds 200 watts. At the same time, bimetallic devices are not so sensitive to the quality of the coolant. The disadvantage of these devices is their high cost.

The dependence of heat transfer on the type of connection

The characteristics of the battery depend not only on the temperature regime of the coolant and structural material, but also on the type of connection of the device to the heating system:

• direct one-way connection - the most efficient, reference type of connection;
• diagonal connection - used to reduce heat loss if the battery has more than 12 sections;
• lower connection, in which up to 10% of energy is lost - used to connect to the heating system in the floor screed;
• single-pipe connection is the most unprofitable, heat losses fluctuate within 30-45%.

Options for increasing heat transfer

There are several ways to increase heat output:

1. The radiator must be clean, therefore it needs systematic wet cleaning.
2. Too thick a layer of paint on a cast-iron battery disrupts heat transfer. Therefore, when painting, it is necessary to use special paints with reduced resistance to heat transfer.
3. Before applying paint to a used battery, the old paint must be carefully removed. For painting, it is better to use dark enamel applied in two layers. Dark colors allow you to increase the heating power by approximately 10%. Light-coloured surfaces usually look more spectacular, but are not as effective for heating purposes.

1. The battery must be installed correctly: without tilt, at the correct distance from the wall and floor.
2. The radiator must not be covered by decorative grilles or curtains.
3. There should be no blockages in the inside of the device that interfere with the circulation of the coolant.
4. Foil screens that can be installed on the wall behind the battery increase heat transfer.
5. The reason for the decrease in temperature may be too tight valves. Moreover, attempts to crank them may not be successful due to the formations that have arisen on the thread. In this case, you need to call a plumber.
6. If during the heating season it turned out that some segment of the radiator is cold, we are talking about a violation of the movement of the coolant due to the accumulation of foreign formations at the bottom of the device. Gently tapping on the device can get rid of the problem. You can also turn on an electric stove or electric heater nearby. When the water in the battery is heated, a vortex movement is initiated, which can move rust or debris from the place of deposition.
7. The temperature may also drop due to repair work at the neighbors, if they made the riser narrower when installing "warm floors" or began to heat additional rooms, which reduced the pressure in the system.

So, the factors of good heat transfer of radiators: the model and material of the device, the type of connection, the correct calculation of the number of sections, taking into account the characteristics of the room, compliance with the rules for operating the equipment. To achieve maximum heat transfer, it is necessary to take into account all these parameters. The reward for this will be warmth and comfort in the room.

Heaters transfer heat to the room, which enters them from the water (heat carrier) circulating in the heating system. The heat output depends primarily on how steel heating radiators transfer heat, either by convection or radiation, one of which always prevails in certain types of radiators. Recall the physics lessons at school, which discussed the methods of distribution (transportation) of heat:

How do radiators transfer heat?

• Heaters transfer heat due to their thermal conductivity, as a consequence of the direct impact of body particles. We have to deal with a situation where we heat up a metal plate on the one hand, but how quickly this happens, on the other hand, depends on the properties of the known thermal conductivity of the material from which in our case the radiator is made;
• Heaters transfer heat by radiation, when the vibrations of the molecules of a heated object emit electromagnetic radiation (in the case of room temperatures this will be infrared radiation), which, in turn, is absorbed by another body, as a result of which it is heated;
• Heat transfer heaters by convection, where a mass of heated gas or liquid moves (moves) due to differences in density (hot air rises, just like hot water in a tank).

To summarize, for space heating the phenomenon of thermal conductivity is of great importance, as in the design of radiators. The space is heated by radiation and convection. Radiation makes a decisive contribution (about 70%) to the heating of surfaces (floor or walls), which is rightfully considered a great advantage for underfloor and wall heating systems.

The amount of heat transferred by convection and radiation depends on the design of the radiator, which affects how people feel when they are in a heated room. At the same time, simply heating the air is not enough for many people to keep warm. Only a real feeling of warmth is offered by the radiant radiation of heated objects in our rooms (many people still remember the warmth of a tiled stove, fireplace). Some people are more sensitive to such heat. Now there is nothing surprising in the fact that in houses equipped with modern heating systems, stoves and fireplaces are becoming more and more popular.