Heaters. Types and selection criteria
Radiators that used to seem unattractive are now becoming popular and we match them to interior design. It is always worth taking the help of a wizard who will tell you which devices to choose so that they not only look beautiful, but are also reliable in operation.
For a number of different reasons, steel radiators are becoming increasingly popular with both builders and those who are renovating their homes and planning to change heating elements. We will try to outline the main pros and cons of steel radiators in general terms.
- Types of radiators
- Tubular radiators
- Sectional steel radiators
- Panel steel radiators
- How to choose power?
Types of radiators
Tubular steel radiators, often called heating registers, are made from steel pipes. Hot coolant flows through the pipes. As in the case of sectional steel radiators, welded joints make the structure more airtight.
However, due to relatively thin walls, such devices are sensitive to water hammer, although they can withstand high operating pressures up to 15 atmospheres. The simplicity of the design allows designers to create the most incredible shapes of such radiators, which is why interior designers are very fond of such radiators. But, remember that the price of tubular radiators is very high.
Tubular — for bathrooms, as well as hallways and rooms. Most often made of steel or copper, sometimes aluminum. These are aesthetic coils or «ladders», consisting of two collectors — distribution and collecting, connected by many pipes. The cross section of pipes can be round, oval, triangular or square.
Tubular radiators often equipped with towel holders, shelves and even mirrors. They have a different shape: a horizontal or vertical ladder, bent or similar to cast-iron «finned» radiators. They are light, low water and work well in automated pumping installations.
Note: before turning on the heater, close the shut-off valve that supplies water to the radiator so that the heater does not heat the water in the entire system.
Sectional steel radiators
Sectional steel radiators differ little in their appearance from their «colleagues» in the cast iron workshop. However, they have a number of differences that distinguish them favorably for the better. The connections of such radiators are welded, and this provides higher strength.
Such radiators withstand high (up to 16 atmospheres) working pressure. The service life of such devices is 50 years. However, it would be useful to say that the cost of sectional steel radiators is high, which makes them not the most popular product on the market for heating devices.
Panel steel radiators
A steel panel radiator is usually a rectangular structure. The design is based on two steel sheets connected by welding or stamping, on their outer surface there are stamped vertical grooves that form channels inside the panel through which water circulates.
In addition, these recesses increase the area of the product, which increases the thermal efficiency. As a rule, one, two or three such panels are made, convection fins are attached to the inner side of such panels, made of U-shaped profiles, which are installed vertically.
The design of a panel steel appliance equipped with such profiles allows heating the air not only due to radiation, but also due to convection. The design of this type of heating device makes it possible to achieve heat transfer comparable to cast-iron radiators and much higher than that of aluminum radiators.
Another important quality of a steel panel product is that seven times less volume of coolant is required for heating than for its cast-iron counterpart, while the temperature of the coolant can be as much as twenty degrees lower.
Thus, there is a significant saving of thermal energy, and hence fuel and, consequently, the cost of space heating. Panel steel radiators are lightweight and compact. A wide range of panel radiators of different sizes makes it easy to choose the right heat output.
The efficiency of such radiators reaches 75%. Another advantage of these products is their very low cost. The working pressure for which these devices are designed (up to 13 atmospheres), and other design features also allow them to be used in systems with central heating. However, such devices are sensitive to corrosion, which requires high-quality water treatment.
How to choose power?
The selection of the power and size of the radiator is best left to a specialist who takes into account factors such as:
— quality of wall insulation;
— the need for heat in the room (the need for a corner room exposed to cold winds is different from the need for heat in the hall or bathroom, where the temperature should be 25 degrees, and yet another in the bedroom, where 18 degrees is enough);
— the area of windows and doors in the room;
is the temperature of the water circulating in the system.
It is assumed that in a house with good thermal insulation, the heat demand in the rooms is 80-100 W/m2, and in the bathrooms 120 W/m2.
For a room of 20 m 2, a heater with a power of about 1800 watts is required. However, when choosing a heater, you should check the parameters at which it reaches the set power (these are: supply water temperature, return water temperature and room temperature). In installations with heated high temperature boilers, the radiators operate at 90°C/70°C/20°C, and in low temperature heated or condensing boiler installations — 75°C/60°C, respectively ,/20°C or 55°C/45°C/20°C.
Therefore, the heaters for these «cooling» units must be larger than those used with conventional boilers (90°C/ 70°C/ 20°C):
— 1.25 times when operating at 75 o C / 65 o C / 20 o C;
— 2.5 times when operating at 55 o C / 45 o C / 20 o C.
Manufacturers have heater power conversion tables depending on operating parameters.