Plate heat exchangers for hot water supply. Reliable Ridan heat exchangers for stable operation of DHW systems

Plate heat exchangers are used in heating systems, hot water supply, air conditioning, and water heating (swimming pools). Two types of such installations are produced, differing in design features and manufacturing technology - dismountable and soldered. Brazed heat exchangers (mass-produced) are more widely used. Collapsible ones are usually made to order.

Application of heat exchangers

Gasketed and soldered heat exchange units are used to transfer heat without stirring liquid media. They are installed in heat exchange circuits various sources thermal energy at thermal and power plants. These could be energy systems on solar powered, geothermal, industrial systems recycling of waste heat.

Heat transfer process

In soldered and gasketed plate heat exchangers, heat exchange occurs in the process of parallel movement of the energy-giving and heated liquid media. The design of the heat exchanger is such that an optimal ratio of mass distribution and movement speed of both media is achieved. Due to this, it is possible to minimize dimensions installation, making it as efficient and compact as possible.

Design features of heat exchangers

Brazed plate heat exchangers do not use internal gaskets or special clamping fixtures. They have a compact one-piece design consisting of a base, plates, channels between the plates, and connecting pipes. The plates in the heat exchanger are soldered together. As construction material We use stainless steel - a strong, durable, corrosion-resistant metal.

The most common soldering material is copper. For devices used in the food industry, as well as in contact with aggressive environment, use nickel soldering. Soldering is carried out according to vacuum technology at all points of contact. This ensures maximum heat transfer, high strength for rupture, shear and compression.

Advantages

The main advantages of brazed plate heat exchangers are considered to be high operational reliability and heat transfer efficiency. This ensures a compact design, low weight, and insignificant internal volume of the installation. All this is combined with ease of installation, ease of operation and a relatively low price. All manufactured heat exchange units undergo pressure testing to detect leaks in each circuit.

To reduce costs by almost a third when purchasing heat exchange equipment, you should pay attention to heat exchangers Ridan DHW. Cost reduction occurs thanks to new scheme connecting a boiler, rather than the usually used two-stage hot water supply scheme. It's about about a parallel circuit with a lower return temperature, which consumes the same amount of coolant.

The main areas of application of plate heaters today are the hot water supply system in municipal heating, the metallurgical and food industries, petrochemicals and large-scale energy. Basis Corp specialists will help you make an accurate selection of a heat exchanger for Ridan hot water supply. This plate-type device is installed in parallel with the heating system. The operation of the equipment is controlled by one valve.

Refusal of the two-stage scheme will help achieve the following indicators: will reduce funds at the time of purchase and installation by up to 30%, keep the same costs as with a two-stage scheme and simplify common system heat supply.

We supply high-quality Ridan heat exchangers for domestic hot water supply from the manufacturer.

If you need a Ridan plate water heater, then the best prices in Moscow, employees of the Basis Corp company will offer it, since we work directly with the manufacturing plant and are its official representative in the capital. Our price list for the Ridan DHW heat exchanger will help you verify the affordable cost of the equipment offered. We not only sell boilers for hot water supply systems and spare parts for them, but also offer a regular service service. It includes cleaning and rinsing the device from various contaminants, deposits and scale, replacement of seals and plates.

Lamellar DHW heat exchanger Ridan heats the water thanks to metal plates made from high quality of stainless steel or titanium and having a corrugated surface. The movement of liquids occurs through different channels between the plates in countercurrent, and special seals prevent their mixing. If you are interested in purchasing a modern, new generation boiler, then choose a plate model, and the Basis Corp. company, in turn, will always offer you the most favorable price in Moscow on him.

Cold and hot water supply – two engineering systems, Related comfortable conditions living in a private house. And if with a cold water supply everything is more or less clear, because this is a piping from a pump that draws water from a well or borehole. That hot water supply is a more complex network, and its operating conditions mainly depend on heating element, which is most often a heating boiler. And since there are a lot of boiler units, meaning their design features, then accordingly the water in them will be heated differently. One of the options that is used most often today is heat exchangers installed in or outside the boiler for hot water supply to a private home.

DHW diagram with installed heat exchanger

Heat exchangers got their name from their intended purpose. That is, temperature exchange occurs in these units. And since we are talking about hot water supply, it is clear that the heat from hot water It is transferred cold so that it also becomes hot when it comes out. And since the hot water supply does not have its own heat source, that is, the water in the system is not directly heated by the energy carrier, then accordingly there must be its own heater or system that would heat the water. And such a system is heating.

It turns out that hot water in heating system passes through a heat exchanger and gives part of its heat through the walls of the device to cold water located in some container. And such containers are called boilers. And all heating technology is called indirect because there is no direct interaction of the energy carrier with the heating design of the hot water supply system.

Types of heat exchangers

The simplest heat exchanger is a coil made of metal pipe. It is clear that metal is an ideal material with high thermal conductivity, which means that heat transfer will be fast and as efficient as possible. And the larger the diameter of the coil, the more turns it has, the more intensely it will give off heat, because this increases the heat exchange area. Of course, the intensity of heat transfer will also be affected by the difference between cold water in the boiler, and hot in the heating system. And the smaller the difference, the better. True, it should be noted that the water in the well usually averages +10C, add here winter temperature, then it turns out that if it is necessary to bring the water in the hot water supply to a temperature of +40-45C, you need to heat the water in the heating system to +80-90C.

Plate heat exchangers

Another type is plate heat exchangers for hot water supply. Their design is based on corrugated plates, which are installed between the plates and compressed together with special bolted connections.

Plate heat exchangers are superior to tube heat exchangers in terms of efficiency. It's all about the very plates from which the device got its name. They have big square heat transfer, themselves a large number of, they are heated by pipes that penetrate all the plates in four places, hence, in principle, their strong heating. The photo below shows such a unit.

Direct heating technology

ABOUT indirect heating water is said, but there is another heating technology called direct. That is, the heat exchanger in the hot water supply system is installed directly in the firebox heating boiler. That is, the device is heated directly by the energy carrier. As practice shows, in such a DHW system, combined type units are usually installed. their design is based on a pipe coil along which it moves cold water. And to enhance heat reception, additional plates are installed, thereby increasing the intensity of heat energy intake. The photo below shows such a unit. By the way, these devices are called primary.

Primary heat exchanger

They are most often made from stainless steel or copper alloy. It should be noted that this type heat exchangers are subjected to heavy loads. This doesn't just apply to temperature. The thing is that processes occur inside the pipes under the influence of high temperatures, which lead to the rapid deposition of minerals and various salts on the walls. And this is a decrease in the diameter of the pipe, and the consequence is a decrease in the intensity of heat transfer towards the water passing through the pipes. Therefore, it is very important, when operating the water supply system of a private house, to pay attention to the quality of water taken from a well or well. And the simplest thing in this case is to install filters for various purposes, that is, to organize a competent water treatment system.

Conclusion on the topic

Select one or another model of heat exchange device according to design features- this means choosing the hot water supply system itself. Or more precisely, an approach to implementing the principle of heating water for hot water supply. Therefore, even at the stage of designing and planning heating and hot water supply systems, it is necessary to take into account how the water will be heated.

The shell-and-tube design of the heat exchanger, where the media move towards each other through tubes placed one inside the other, is gradually becoming a thing of the past. Although these bulky devices of large dimensions functioned quite efficiently, they could not boast of a large consumption of the heated medium. They were replaced by new units - high-speed plate heat exchangers. This article is devoted to their design, principle of operation and application.

Design and principle of operation of a plate heat exchanger

Structurally, the unit is fundamentally different from its shell-and-tube predecessor. The thermal energy exchange surface area of the latter was increased by increasing the length of the coil, hence large dimensions apparatus. In the new heat exchanger, this is achieved by increasing the number of plates of the same area.

Having the same power, it is three times smaller in size than a shell-and-tube one, and at the same time is capable of providing a large flow rate of the heated medium, for example, water for domestic hot water needs. This is where the second name of the unit came from – high-speed. The diagram below shows the design of a plate heat exchanger:

1, 11 – supply and return pipes for connecting the heating medium (coolant); 2, 12 – inlet and outlet pipes of the heated medium; 3 — front fixed plate; 4, 14 – holes for coolant flow; 5 – small sealing gasket in the form of a ring; 6 – working heat exchange plate; 7 – upper guide; 8 – rear movable plate; 9 – rear support; 10 – hairpin; 13 – large gasket along the contour of the plate; 15 – lower guide.

The diagram shows plate heat exchanger for heating of the simplest design with pipes located on opposite sides of the unit. Sandwiched between two plates mounted on two guides certain number plates with rubber seal between them. On each plate, in order to increase the exchange surface, relief corrugation is made, as shown in the photo:

The connecting pipes can also be located on one side of the device, on the front plate, which does not affect the operating principle of the plate heat exchanger. It consists in the fact that the space between each subsequent plate is alternately filled with either a coolant or a heated medium. The order of filling is ensured by the shape of the gaskets; in one section they open the way for the flow of coolant, in the other for the heat absorber.

During operation, in each section, except the first and last, intense heat exchange occurs through the plates on both sides at once. Both media flow through their sections towards each other, the heating one is supplied from above and exits through the lower pipe, and the heated one - vice versa. How it works shows functional diagram plate heat exchanger:

Specifications

Plates and gaskets can be made from various materials, their choice depends on the purpose of the unit, because the scope of application of such heat exchangers is very wide. We are considering heating and hot water systems, where they act as thermal power equipment. For this area, the plates are made of stainless steel and the gaskets are made of NBR or EPDM rubber. In the first case, a stainless steel heat exchanger can operate with water heated to a maximum temperature of 110 ºС, in the second - up to 170 ºС.

For reference. These heat exchangers are also used for various technological processes when acids, alkalis, oils and other media flow through them. Then the plates are made from titanium, nickel and various alloys, and the gaskets are made from fluorine rubber, asbestos and other materials.

Calculation and selection of a heat exchanger is carried out using a specialized software according to the following parameters:

required liquid heating temperature;
initial coolant temperature;
required flow rate of the heated medium;
coolant consumption.

Note. The heating medium flowing through a plate heat exchanger for hot water supply can be water at a temperature of 95 or 115 ºС, or steam heated to 180 ºС. This depends on the type of boiler equipment. The number and size of the plates are selected in such a way as to obtain water with maximum temperature no more than 70 ºС.

It must be said that the advantages of plate heat exchangers lie not only in their modest size and ability to provide high flow rates. The fact is that the range of selected exchange areas and costs for the units under consideration is extremely wide. The smallest of them have a surface area of less than 1 m2 and are designed to flow 0.2 m3 of liquid in 1 hour, and the largest - 2000 m2 with a flow rate of over 3600 m3/h. The table below shows specifications shown by the operation of plate heat exchangers famous brand ALFA LAVAL:

According to their design, heat exchange units are of the following types:

collapsible: the most common option, allowing for quick and high-quality repair and maintenance of a high-speed heat exchanger;
soldered or welded: such devices do not have rubber gaskets, where the plates are rigidly connected to each other and placed in a solid body.

Note. It is brazed heat exchangers that many craftsmen use for private homes, adapting them for heating or cooling water.

Heat exchanger piping

As a rule, the installation of such thermal power equipment is provided for in individual boiler houses of multi-apartment residential buildings or industrial enterprises, as well as in heating points of centralized heating systems. The goal is to obtain water for domestic hot water needs at a temperature of up to 70 ºС or a coolant up to 95 ºС when using steam and high-temperature hot water boilers.

Due to its small dimensions and weight, installation of the heat exchanger is quite simple, although powerful units require a foundation. In any case, the foundation bolts are poured, with the help of which the device is securely fixed in its place. The coolant is always supplied to the upper branch pipe, and the return pipeline is connected to the fitting located below it. The heated water supply is connected, on the contrary, to the lower pipe, and its outlet to the upper one. The simplest scheme The plate heat exchanger piping is shown below:

The coolant supply circuit must have its own circulation pump installed on the supply pipeline. In accordance with the rules, in addition to the working pump, a reserve pump of the same power is installed in parallel. If the DHW system has a return circulation line, then the connection diagram takes the following form:

Here, the heat of water flowing through a closed DHW circuit is used, cold water from the water supply is mixed with it, and only then the mixture enters the heat exchanger. The outlet temperature is controlled the electronic unit, controlling the valve on the coolant supply line. Well, the last scheme is a two-stage one, allowing you to use thermal energy heating return line:

The scheme allows you to save significantly by removing excess load from boilers and using the available heat to the maximum. It should be noted that in all schemes filters are installed at the entrance to the high-speed heat exchanger. The reliable and durable operation of the unit depends on this.

Conclusion

As practice shows, a modern plate heat exchanger is still slightly inferior to the old shell-and-tube heat exchanger according to one criterion. Producing a high flow rate, high-speed units slightly underheat the exiting liquid; this drawback was discovered by specialists during operation. Therefore, when selecting the number and area of plates, it is customary to make a small margin.