Heat generators: air, water and vortex

Recommendation points

• History of heat generators
• The device and principle of operation of the heat generator
• Types of heat generators
• Vortex heat generator – history
• Where does excess heat energy come from in vortex heat generators
• Manufacturers of vortex heat generators and their cost

In this Article: History of Heat Generators principle of operation and device; types of heat generators; manufacturers and average cost of heat generators; the history of the vortex cavitation heat generator; the principle of the vortex heat generator; manufacturers of cavitation heat generators in the CIS.

In the winter season, the premises need artificial heating, otherwise its inhabitants will personally experience all the delights of the ice age. Central heating in apartment buildings, individual heating in private cottages … but what about large areas, for example, sales areas and warehouses? And with construction sites or, say, car services, where cold air constantly flows from the outside? The only way to heat a large area is air heating, built either on heat guns or on heat generators. This article will cover heat generators.

History of heat generators

The invention of the convective heat generator is directly related to the invention of Robert Bunsen, an atmospheric burner named after him. The first heat generators put on the market in 1856 by the English company “Pettit and Smith” were equipped with an atmospheric burner similar to the Bunsen burner, only of a larger size.

German experimental chemist Robert Wilhelm Bunsen

In 1881, the Englishman Sigismund Leoni received a patent for a new type of heat generators – the flame of a burner in them heated an asbestos plate, which transfers heat to the air. Subsequently, asbestos was replaced by refractory clay, today replaced by more durable refractory materials.

An atmospheric burner and a refractory plate above it are the main elements in the design of any modern heat generator..

The device and principle of operation of the heat generator

In terms of their tasks, heat generators are similar to heat guns – the difference is that these units can only be stationary. Typical design of a heat generator: a fan (axial or centrifugal), above it there is a combustion chamber, a burner is introduced into its lower part, an air heat exchanger is located above the burner. The hot gases formed in the combustion chamber are fed to the heat exchanger and then led to the chimney. The air flow blown by the fan heats up in the heat exchanger to 20-70 ° C, then enters the heated room or the duct ventilation system.

Depending on the power of the fans installed in their design, heat generators can develop an output static pressure of 100-2000 Pa.

In terms of thermal power, heat generators differ into two types – up to 350-400 kW (in a single housing) and up to 1000 kW (consist of heat exchange and ventilation sections).

In heat generators intended for air duct heating systems, the heat exchanger and the combustion chamber are made of stainless steel; a condensate drainage system is additionally introduced into their design.

Types of heat generators

The main difference among the existing models of heat generators is what kind of fuel is used in them and what kind of coolant is to be heated. Heat generators can operate on solid fuel, gas, diesel fuel and be equipped with a universal burner. The heat carrier in heating systems, which is heated by a heat generator, can be either water or air.

Gas heat generatorsdesigned for continuous supply of warm air to the premises, they are installed in a vertical position. The heat exchanger installed in them extracts a significant part of the heat from the combustion products, reducing the volatility of flue gases – the exhaust pipe for gas heat generators must be equipped with a fan. If the design of the heat generator contains a closed combustion chamber, under which the blower is located, then the probability of reverse thrust is minimal – all combustion products will be removed through the chimney, therefore such gas heat generators are considered the safest. In most cases, the efficiency of gas-fired heat generators is 85-90%.

When choosing a model of a gas heat generator, it is necessary to pay special attention to its ability to work at reduced gas pressure. When building heating on a gas heat generator in the absence of central gas supply, it will be especially convenient to install a gas tank with a volume of 2500 liters or more (the required volume depends on the heated area of ​​the building).

Diesel heat generators, as fuel for which kerosene or diesel fuel is used, they are well suited for heating industrial premises with a significant area. They are equipped either with a nozzle that sprays fuel through the combustion chamber, or the fuel is supplied by a drip method. Subject to continuous operation, they are refueled twice a day..

For combustion in heat generators with a universal burner, both diesel fuel and waste oil, fats of vegetable and animal origin are used. They are especially convenient in enterprises where there is a problem with the disposal of fats and waste oil. However, the thermal power of the heat generator, in which waste oil and fats is burned, will not exceed 200 kW; when burning diesel fuel, a higher thermal output is achieved. Regardless of the type of fuel used, this type of heat generator, like any other, needs a chimney. When burning waste oil, the formation of slags is inevitable, which must be removed daily – for greater convenience, two combustion bowls will be required, one of which will be used to replace the other during cleaning and to reduce the downtime of the heat generator.

Solid fuel heat generatorshave a different design than those described above – being something between gas / diesel heat generators and between a conventional furnace. They are equipped with a fan blowing air through a heat exchanger and supplying it to the heated rooms; they have grate bars and a fuel loading door. Solid fuel heat generators burn dry wood, peat briquettes, coal, and various agricultural waste. Such heat generators have an efficiency of the order of 80-85%, which is slightly less than those operating on gaseous and liquid fuels – 85-90%. It should also be noted the large size of solid fuel heat generators and significant waste in the form of an incombustible part of the fuel..

Heat exchangers in heat generators can be cast iron or steel: their first type is more resistant to corrosion, but rather massive, heat exchangers of the second type, on the contrary, have less weight, but are subject to corrosion. Both types of heat exchangers do not tolerate impacts well, therefore the transportation and installation of heat generators must be carried out with the utmost care.

The advantages of air heat generators are higher, in comparison with water heating, the efficiency and speed of heating the premises, and when working on waste oil – saving money on fuel, not to mention solving the problem of waste disposal.

The average cost of a 400 kW heat generator will be RUB 90,000. On the Russian market there are heat generators from Master (USA), Kroll (Germany), Sial and ITM (Italy), Benson Heating (England), FEG Konvektor GF (Hungary).

When choosing an air heat generator, one should consider those models in which the air is heated indirectly, i.e. the combustion chamber is completely isolated from the coolant. In this case, combustion products are guaranteed not to penetrate into the air heating channels, there will be no need to mix air from outside to the air inside the premises. However, such heat generators have a higher price, weight and dimensions..

Heat generators with the functions of providing hot water and heating can completely solve the problems of heat supply, for the most part they run on solid fuel.

Vortex heat generator – history

This type of heat generators deserves special attention, largely due to the opposition of its supporters and opponents..

In the 20s of the last century, the Frenchman Joseph Rank, conducting research in the air chamber of a cyclone installation, found that, being swirled, gases in a cylindrical or conical chamber are separated into two fractions – with a higher temperature at the edges and a lower temperature in the center. moreover, the fraction in the center, in contrast to the marginal one, rotates in the opposite direction. In 1934, Rank received a patent in the United States for his “vortex tube”.

German Robert Hilsch in the 40s continued the research of his French colleague, achieving a greater difference between the temperatures of two air streams leaving the Rank vortex tube due to its improved design.

In the 50s, the Soviet scientist A. Merkulov set up a series of experiments with the Rank vortex tube, deciding to pump water into it instead of gas – theoretically, there should not be a temperature difference in the water that was driven through the Rank tube, because, unlike gases, water cannot be compressed … Contrary to expectations, the bifurcated vortex flow of water was heated and cooled similarly to gases, which puzzled Professor Merkulov – he could not explain the reasons for this phenomenon.

By the way, the creator of the first vortex heat generator is often called the Austrian self-taught inventor Viktor Schauberger, known for the suction turbine he built in 1921, which works only on water …

Twenty years ago, American James Griggs, whose area of ​​interest lay in the field of heating, was the first to build a water heat generator based on the Rank pipe principle. James was disappointed with the water heaters with heating elements – the salts in the water formed a scale on the heating elements, causing the coil to overheat and failure of the heating element. Based on the fact that the heating elements have an efficiency close to 100%, and the electric motor rotating the heat generator is about 90-95%, James Griggs decided to compensate for the greater energy consumption by not having to replace the heating elements that had burnt out from scale formation. Griggs’s calculation was for friction to cause the water to heat up. The American engineer turned out to be right – the heat generator he created really heated water, and its internal structure was not subject to wear from various impurities and salts present in the water. But, to the extreme surprise of James, the calculation of energy costs did not reveal the planned 10% energy loss, but, in comparison with heating systems with heating elements, 14% savings! Having carried out experimental tests in 1992, Griggs found that for every joule of electricity spent on the operation of a heat generator, a heater creates 1.5 joules of heat. After spending another two years trying to find out the reasons for the occurrence of excess energy and without finding out them, James Griggs in 1994 received a patent in the United States for a rotary-cavitation heat generator he created.

Where does excess heat energy come from in vortex heat generators

The Griggs heat generator is designed as follows: an aluminum rotor is placed in a cylindrical steel body, holes are drilled along the rim surface; the case is closed with a flat steel cover fixed to it with screws. In the flat covers, on each of them, there is an inlet for the flow of water, in relation to each other, the inlets on both covers, mounted on opposite sides of the body, are located on the same line. Water, coming from one side to the rotor, bypasses it along the rim and flows out from the opposite side with a higher temperature than it was originally.

The reason why the water is heated is most likely due to cavitation. When entering the rotor and filling the holes along its rim, water sticks to them, but the centrifugal force causes stretching of the water adhering to the holes – its droplets break out of them, rush to the walls of the body and cut into them. The resulting shock wave and increasing pressure “collapse” the large number of gas and vapor bubbles, causing in each of them a pressure of hundreds of thousands of atmospheres and a temperature of more than 106 ° C – acoustic cavitation occurs.

The theory described above is based on the phenomenon of sonoluminescence, discovered in 1934 by German scientists N. Frenzel and H. Schultes, working on a sonar for submarines. They found that sound waves cause expansion and contraction of gas bubbles in water – under the influence of vibrations and in time with them, the size of the bubbles changes from several tens to several microns, their volume changes several times. As a result, the gas contained in the bubbles becomes hot enough to melt steel and even emits light..

Manufacturers of vortex heat generators and their cost

The production of vortex heat generators for the CIS market is carried out by a number of manufacturers, each of them has a patent for a model it produces on the basis of the model developed by the technical specifications – there are no state standards for vortex heat generators. Their production is carried out by the companies “YUSMAR” LLC (Moldova), the Russian NPP “Alternative energy technologies and communications”, “Noteka-S” LLC, the “Angstrem” NPP, “ORBI” LLC, “Kommash Plant” JSC and others. Over the past 20 years, the inventors of vortex heat generators received about 50 patents.

The cost of vortex heat generators with an electric motor power of 55 kW / h will average 290,000 rubles.