Air heaters

What are heaters: purpose and types

In the most general sense, a duct heater, or air heater, is a heat engineering device designed to heat the (ambient) air blowing over it. By and large, both the stove (like a heating device) and the fireplace are also duct heaters. But it is more customary to call technical devices of two types as heaters:

1. with direct heating of air from an electric heating element. These are both widespread household "wind blowers" and quite industrial electric heaters or dryers;
2. with indirect heating of air from another heat carrier (which is hot water, steam, air, freon, etc.) circulating in a closed heat exchange circuit (channel). So, familiar to everyone: an ordinary heating "battery" in an apartment, a car radiator, a condenser of a refrigerator or an air conditioner - all these are varieties of such a heater - a heat exchanger, where only one medium (coolant) channeled in a closed pipeline system participates in heat exchange, and the second heat exchange medium is ambient air.

Air heaters can be:

• with natural circulation of heated air by means of temperature convection (heaters-convectors) - this is a simpler and cheaper type of heating (heating, drying) equipment, but much less efficient in terms of the amount and rate of heat transfer;
• forced draft, usually with an air blower, usually driven by an electric motor or internal combustion engine. Devices with forced airflow are more energy-consuming to operate, require electricity supply or an autonomous power plant, but at the same time, they can provide the transfer of much higher thermal power, which is usually expressed in large volumes of air warmed up in a short time.

Heaters of the second type (heat exchange) are much more interesting in technical and technological terms. They are remarkable in that they allow both a multifaceted effect of a channeled coolant on the surrounding air (not only heating, but also cooling), and a thermodynamic effect from the ambient air on the coolant channeled in the system (not only its cooling, but also heating). Therefore, channel heat exchangers can be:

• actual air heaters (heaters, heaters), which are widely used in water and steam heating systems, all kinds of drying units;
• coolers, evaporators, condensers, which are widely used: in self-propelled and non-self-propelled equipment, food, chemical (including pharmaceutical) equipment, air and water conditioning systems, refrigerators for household, economic and industrial purposes.

Structural diagram of the heat exchanger (radiator)

Duct heating devices, which by design practically do not differ from duct air heaters (air heaters), but are used on the contrary, to cool the ducted heat carrier with ambient air, are often called radiators. But on the other hand, a heating radiator (heater) is also a widely used technical term. Therefore, an equal sign can often be put between the concepts of a duct heater, air heater and radiator, at least because of the generality of their design scheme.

The structural diagram of the heat exchanger (radiator) is quite simple. It usually includes:

• duct-forming (pipe) system, usually zigzag (coil type) or collector (consisting of inlet and outlet (return) pipe collectors, connected by several parallel pipe bridges - nozzles that form a "step" of the radiator), through which the channeled coolant is passed;
• heat exchange plates (fins) of a large heat exchange area, which, in contact with the pipe system and being heated from it, transfer heat to the air that washes them. Heat exchange fins are often integrated with tubes (pipes) and are integral with them.
• forced air blower fan (if provided by the design);
• connecting pipes of the appropriate type for connecting a heater (radiator) to the delivery and outlet (return) lines.

The working medium (channeled) in such heat-exchange type heaters (radiators) can be not only hot water, but also superheated water vapor, hot air, industrial or engine oil, refrigerants, reagents and other media. According to the used working (channelized) environment, the heaters (radiators) differ from each other. But not so much a fundamental design as the construction materials and seals used, which can be:

• corrosion-resistant and unstable;
• with varying degrees of heat resistance;
• oil-resistant, resistant to refrigerants (freons), chemicals, etc.

In order to intensify heat transfer, or strengthen the structure under high operating pressure, the tubes (pipes) of heat exchange heaters (radiators) can be:

• thick-walled and thin-walled;
• smooth-walled and intensified (helicoid).

It is worth noting that hydraulic (water) heaters and collector-type radiators have vertically arranged collectors and horizontal pipes (to ensure liquid circulation even if the level is insufficient), and steam-gas heaters or condensers, on the contrary, have horizontal collectors and vertical pipes (to facilitate drainage liquid condensate).

Parameters for the selection of an air heater

The main technical parameters that determine the choice of an air heater (radiator) are:

• working medium (water, steam, gas, oil, refrigerants, etc.);
• operating and maximum allowable pressure in the ducted heat carrier system;
• hydraulic resistance of the apparatus;
• operating and maximum permissible temperature of the coolant at the inlet (in the supply or discharge line);
• coolant temperature on the outlet (return) line;
• temperature of the supplied (ambient) air: average, minimum, maximum;
• required performance: according to the transmitted (removed, supplied) thermal power, or according to the volume of heated air.

Advantages of heaters produced by OPEKS Energosystem

The assets of OPEKS Power Systems include:

• many years of experience in the production of heating equipment of the greatest complexity;
• the most modern production base;
• continuously improved: a culture of engineering design and a culture of production that meet modern requirements and standards in the industry;
• the strictest quality control system.

Due to the complex of production conditions, heat exchange heaters (radiators, coolers, condensers) produced by OPEKS Energosystem are characterized by:

• high accuracy of engineering calculations and design - the device will exactly meet the stated parameters, or technical specifications;
• high speed of design and manufacture, even for individual projects;
• using only high-quality construction materials and seals, high-tech methods of their connection, which will provide a significant margin of safety and durability of the air heater (radiator) even for the most extreme operating conditions;
• general impeccable workmanship, which guarantees the absolute tightness of the system and its long-term operation, not less than the standard (warranty) period.