Radiant Heat Design

In the harsh Canadian climate issue Radiant heating is, without doubt, one of the most important for owners of private houses and cottages. Traditional stoves for solid fuel is not able to cope with Radiant heating, even very modest suburban home, and connect to the centralized heat supply network (city or township), as a rule, it is not possible. Therefore, to ensure a private house warm and cozy all year round, even in extreme cold, the most acceptable option would be to use an autonomous Radiant heating design.

There are three main schemes of Radiant heating:

1. Traditionally, when a liquid coolant is heated in a boiler, then circulates in the system piping and radiators, heats the heated rooms;

2. Air Radiant heating, when used as a coolant air supply after Radiant heating in a heated room for air ducts;

3. Direct Electric, when the Radiant heating facilities carried out without coolant - infrared emitters, elektokonvektorami and other devices in which electrical energy is directly converted into heat.

Since the last two circuits of Radiant heating in our country are still considered exotic (though in Western Europe, Canada and the U.S. quite successfully compete with traditional systems), in this article we pay attention, especially the first scheme, based on the circulation of liquid coolant.

Such Radiant heating and hot water for a private home include Radiant heating devices, pipes, regulatory, and shut off valves vozduhospusknuyu. The source of heat in the boilers are used in different types of fuel. The boiler heats the liquid coolant (as a coolant used specially prepared water), then fed through PEX pipe to room radiators (battery). Flowing through the radiator coolant gives some heat in the room, then returned to the boiler. This circulation of coolant, supported by a Taco (or Grunfos) circulation pump, provides the most efficient heat transfer in the system.

The device of the Radiant heating design shall be provided at the stage of designing and building homes. When posting all the necessary communications in the existing buildings will inevitably have to punch in walls and ceilings. In addition, under the pots in the outdoor performance is required to provide a separate room - the boiler room. If such premises project is not provided, then the boiler can be installed in the bathroom or the kitchen. In this case it is convenient to use wall-mounted models.

The Radiant heating design may be single-and double-circuit. Single-heating design is intended only for space Radiant heating, and double-circuit, in addition to Radiant heating, heat the tap water.

For private houses area of 200 m2 can be used double-pressure boilers up to 30 kW, combined with a circulating pump and expansion tanks. The houses have more space appropriate to set single-circuit high power boilers, and for hot water use capacitive boiler or heat exchanger.

In a two-pipe system separate from the coolant (a kind of Radiant heating element in the form of a spiral) heats water in a special tank - storage water heaters. This solution is very convenient, but a two-fault system, the user remains at the same time and without heat and no hot water. Also note that the Radiant heating of water takes about 25% of the power boiler.

Often, for Radiant heating and hot water use separate single-circuit system (one boiler - for Radiant heating, running only during the cold season, and another, less powerful - for Radiant heating water), however, with all the merits of such a decision, it's pretty expensive.

The optimum capacity of the boiler is made depending on the area heated homes and climatic conditions of the area. It should also be borne in mind that the required boiler output is strongly dependent on the level of thermal protection for the external walling houses and the degree of tightness of the windows.

Below is a tentative power boilers depending on the area served by the house (for the suburbs). House area, m2 boiler output, kW
60-200 Up to 25
200-300 25-35
300-600 35-60
60-100 600-1200

Choosing a boiler depends on what energy resources in the area most accessible. If you can connect to the gas network, it is reasonable to choose a gas boiler, as the most economical. In areas where gas is not fail, you can choose to use either a solid fuel (wood, coal, coke) or liquid (diesel, crude oil) fuels.

In the central region of Canada from the total number of boilers operate at about half the gas, another third - on diesel fuel, 10% - electricity and no more than 5% of the solid fuel.

We briefly denote the pros and cons of different types of boilers and features of their operation.

Not particularly popular with our electric boilers distinguishes the absence of an open flame and, consequently, the combustion products. In the Canadian market presents not a very wide selection of electric boilers - note only the Czech "Dakon PTE", "Proterm" and domestic "Evan" or "Rusne.

Another less common solid fuel boilers deter homeowners inconvenience of their operation, because during the day must be made 3-4 fireplaces, have a stockpile of fuel, the tens of cubic meters, to give space to store it, which requires considerable work on harvesting and loading. In addition, the mode of heat transfer in solid fuel boilers are cyclical, and fluctuations in air temperature in the heated indoor reaches 3-5 ° C during the day.

However, if the choice of solid fuel boilers for any reason is inevitable, there are two ways to neutralize the disadvantages of the boiler.

The first method reduces the number of burners twice due to changes in the extended mode of combustion, which is realized by regulating the degree of opening of the ash of the boiler, depending on the temperature of exhaust gases in the chimney. For this we use a simple device - bulb, stem which is connected with a chain door ash. By decreasing the temperature of exhaust gas bulb is compressed by pulling the rod and covering the ash pit. These devices are equipped with Italian, Finnish, Swedish and other imported boilers. The device can be installed and in domestic boilers.

The second method, popular in Scandinavian countries, based on the use teploakkumulyatorov. In the circuit of the Radiant heating design includes insulated battery hot water capacity 10.2 m3. When melted boiler heats the water in the tank to 80-95 ° C, and then the water by a circulating pump and a simple thermostat ensures a constant mode of Radiant heating for 3-10 days

The most popular among our homeowners' gas and diesel boilers of low power (40 kW) are available, usually in a double-performance or high power - single-circuit, hot water preparation in the latter case is carried out in separate capacitive boilers, heat exchangers.

For oil boilers must foresee a place to store fuel. Tanks with diesel fuel can be installed next to the boiler directly on the ground or burying them. It is important that the length of fuel line, which will be the fuel supply to the burners, in line with the performance of the fuel pump.

The most important part of the gas or diesel boiler is a burner, which can be atmospheric or fan type.

Atmospheric burners cheaper fan, run smoothly and are delivered with the boiler. Their main disadvantage - chuffing at low gas pressure in the network, which is why the flame is close to the burner, causing it to burning.

In burners built-in fan creates airflow that pulls gas from the nozzle. Therefore, such a burner is not afraid to drop in gas pressure of 5-6 mbar. Good burner of this type costs about the same as the average single-circuit boiler cost. Its main disadvantage - loud noise from the fan.

Oil heaters burners produced only fan (or "supercharged"). They have built-in pump for pumping fuel from the tank. To reduce fuel burners can be two-and three-way or with smoothly varying power (baseband). The power increases automatically - only when the increased demand for heat, for example, in the case of severe frosts. This scheme significantly prolongs the life of the boiler.

In today's rich offer of choice of a specific brand of gas or fuel oil boiler seems difficult. As a low-budget version of the usual stop at the boilers of domestic production, although they do not fully meet modern requirements in terms of efficiency, automation and design. Therefore, owners of private houses often prefer products of foreign manufacturers. In the Canadian market are well represented boilers manufacturing companies such as Viessmann (Germany), Buderus (Germany,) Junkers Bosch Gruppe (Germany), Ferroli (Italy), Beretta (Italy), Proterm (Czech Republic), Dakon (Czech Republic).

It should be noted that some manufacturers produce combination boilers that can run on multiple fuels, after some reconfiguration - for example, Canadian boilers "Flame" (from 12 to 40 kW), Czech Dakon FB (from 20 to 42 kW).

For all types of boilers with an open flame should be taken into account that the boiler must be installed on the floor with fire-proof coating so that it has been possible for his care and adequate air access. In the boiler room with limited space should be provided for ventilation. When the air supply from the street entrance hole should be the size of the rate of 600 mm2 at 1 kW of power boiler.

The flue connected to the output of the boiler chimney hole, shall provide the power for sustaining the process of combustion in the boiler. To maintain a constant draft in the chimney is recommended to install the regulator (stabilizer) of thrust. Excessively long or large cross-section chimney can lead to hypothermia flue gases and, consequently, a deterioration of traction and the formation of caustic condensate is corrosive and destroys the chimney up to the failure of a few years of its operation. To avoid this in the bottom of the chimney set the trap for the collection and removal of moisture.

In addition to the boiler, pipes and radiators in the Radiant heating design includes the device to adjust the system (expansion tank and thermostat, coolant pump) and the so-called "Group security" - a pressure gauge, check valve, automatic bleed valve, safety valves.

Expansion tank required to maintain the desired pressure coolant system. When heated, the liquid increases in volume and the "extra" part of it goes into the container expansion tank. By lowering the temperature, this "surplus" goes back into the tube. Capacity expansion tanks is usually 8-12% of capacity, respectively, Radiant heating and hot water.

There are bins of two types: open and closed. Outdoor is a small capacity, the bottom of which is connected to the pipeline, which flows coolant. Outdoor tank set at the highest point of the system (usually the attic). Closed tank has a flexible rubber membrane that is stretched during the filling capacity of the coolant tank and restores the original shape with a decrease in the volume of liquid.

Closed tank is preferable because it can not pour coolant out, he is not in contact with air, that is does not evaporate and is not saturated with oxygen (which prevents corrosion of the inner surface of pipes and radiators). In addition, the tank can be closed to place anywhere in the system. Of course, all modern and high-quality Radiant heating design expansion tank are closed.

To ensure reliability and trouble-free operation of the boiler on the supply line in the Radiant heating design is usually installed safety valve to 6 atm. Despite the fact that the boilers are equipped with protection, safety valve is never superfluous. Such a simple and reliable device is an additional guarantee in case of emergencies, as well as the explosions at an excessively high pressure working environment.

In addition to the system inline filters (water and fuel) to suspended particles from falling into the Radiant heating circuit and the air valve - to remove air pockets from the system. When designing the Radiant heating design is very important to choose the right water purification filters.

An important role in the distribution and use of the heat generated boiler is the choice of Radiant heating schemes.

Twin pipe Radiant heating designs are optimal for individual homes. In such systems, one of the most important elements are circulating pumps, forcing water to circulate in a closed circuit, which increases the heat transfer. The pump also allows you to maintain a constant temperature of water in the hot water system.

Circulation pumps operate continuously, therefore they are presented with such requirements as simplicity and reliability, low power consumption and quiet. Quality Pumps leading foreign manufacturers do not require special lubrication and prevention, the main requirement - providing a stable voltage to the mandatory grounding network.

Modern Radiant heating designs maintain the required temperature in each room with automatic temperature regulator, reacting to outside temperature. For such systems require circulation pumps with integrated electronic control (such as pumps GRUNDFOS ALPHA + type or UPE). They change the speed of the electric motor depending on the needs of the system. Thus, save up to 60% of electricity and reduced hydraulic noise in the pipes.

Frequent and collector Radiant heating design, involving the accession of each of the heaters to the collectors. Such a scheme has a well-regulated Radiant heating, thermal and hydraulic thermal stability. Structurally, the system allows the use of covert laying of pipelines.

Floor Radiant heating designs are widespread in the West, we still unpopular. They are characterized by a high degree of thermal comfort, thermal resistance, hidden pipelines. Maximum temperature of the floor in a room with a constant presence of people is limited to sanitary and hygienic norms in Western countries at 27-28 ° C, in Russia - 26 ° C, bathrooms, swimming pools - at 30-31 ° C. Heat removal from 1 m2 of floor in this regard is limited to the size of the heat flow of 40-50 W/m2.

In conclusion, I would like to briefly mention the little-known consumers of our country's system of direct stationary electrical Radiant heating.

Electric Radiant heating is very reliable, environmentally sound and safe way of Radiant heating, and the costs of equipment and operation can compete with gas Radiant heating. In Northern Europe, particularly in the Scandinavian countries and Finland, an appreciable part (in different countries - from 5% to 70%), low-rise buildings heated by electricity.

Equipment for stationary direct electric Radiant heating can be divided into four groups: Wall Heaters, Ceiling longwave infrared heaters, cable and film system for Radiant heating floors and ceilings, as well as the thermostat and programmable devices. Such diversity leads to an optimal choice for each room depending on its functional purpose. In order to save power electric Radiant heating design can be programmed to automatically turn on and off, or lowering the temperature to a specified level (say, at night or during the absence of hosts). With the increase in energy prices in Russia and similar highly efficient Radiant heating designs are a real chance to win popularity among owners of private houses.

One of the disadvantages of such systems compared with double-circuit-based boilers is that the hot water supply will have to install additional equipment - boiler or single-circuit elektrokotel. Besides, we all have the memory of electricity blackouts, and probably even set an electric Radiant heating in a private home, will not hurry to throw out the old diesel or coal boiler - just in case.

Modern self-contained Radiant heating design can provide warmth and comfort in a private home, even in the most severe frosts.