New developments aimed at saving the cost of heating a house are attracting more and more attention. Among the new products and vacuum heating radiators. These are ordinary batteries externally, but completely different in principle of operation.
They are suitable for both centralized heating systems and autonomous. In this material we will describe in detail the principles of operation of vacuum radiators, their varieties, and also dwell on the nuances that need to be borne in mind when choosing heating radiators for the home.
The content of the article:
- What is a vacuum battery?
- Types of vacuum radiators
- Device and principle of operation
- Positive and negative qualities of devices
- When is a vacuum radiator advantageous?
- Product selection rules
- The subtleties of installation do it yourself
- The best manufacturers of vacuum radiators
- Conclusions and useful video on the topic
What is a vacuum battery?
The radiator was called a vacuum because the air was completely pumped out of the internal cavity of this steel sectional construction. This is done in order to reduce the pressure.
A liquid substance is placed in hermetically sealed sections, which has the property of easily evaporating at a low temperature. This is usually either ethanol or lithium bromide liquid.
In fact, the work of the vacuum battery is based on the principle of functioning of a sealed two-phase thermosyphon. At the same time, it has good heat transfer properties.
The system with such devices is low-inertia. It quickly goes into working mode and almost instantly responds to changes in heat loss.
|Radiator||Coolant flow rate g / sec.||Coolant temperature ° C||The heating surface of the device in% for 2 minutes||The heating surface of the device in% for 4 min.|
The table shows the heating efficiency of different radiators. From the surface of the vacuum heating unit heat release into the room begins much faster.
A vacuum battery has an optimal ratio between thermal radiation and convection in the total heat transfer. The first indicator is 80%, the second - 20%.
Types of vacuum radiators
The line of vacuum devices includes products created for electric heating, vacuum registers, panel radiators. You can find on sale and exclusive designer products.
Special attention should be paid to the model of a vacuum electric radiator, although they are more expensive. This is a good way for owners of rarely visited suburban real estate.
Designer vacuum radiator in the form of a stand for firewood. You can not only put logs on it, but also dry them.
Instead of a horizontal channel with a coolant, this device has a tubular cartridge-type heater with a capacity of more than 50 watts per section.
This heater transfers heat to the aggregate — oil or water — thereby heating the lithium bromide liquid. At installation of such models grounding is necessary.
Device and principle of operation
The difference of vacuum radiators from bimetallic and aluminum analogues can be seen with their external examination. The first distance between the sections is greater. This heating device consists of a housing, a horizontal channel and vertical sections.
Simplified diagram of the vacuum radiator. Its main elements are the collector (1) and vertical sections (2), in which there is a secondary coolant
The first of these elements includes two sections made of 1.5 mm steel. The horizontal channel is the primary circuit located at the bottom and connected to the heat source. A coolant passes through it, which transfers heat to the fluid located in sections that are perpendicular to this channel.
Vertical sections are filled with a secondary coolant - a heat transformer. They are completely isolated from the primary circuit. Their number is directly proportional to the degree of heating of the room. The rate of heating of the fluid affects the pressure inside the cavities. The higher it is, the lower the pressure.
The secondary coolant is a liquid, the basis of which is bromine and lithium. In the circuit, it is in a small volume and tends to boil and evaporate quickly at a small, about 35 ° C, temperature.
Contours have good insulation relative to each other and the environment.
The process that takes place in vacuum batteries looks like this:
- Antifreeze or water heats the horizontal channel.
- Heat from the horizontal channel is sent to the vertical sections.
- The heat transformer boils, causing the entire secondary circuit to be filled with steam.
- The walls of the secondary circuit heat up and release heat to the room.
To ensure the effective transfer of heat rays from the lithium-bromide liquid to the radiator walls, the state of the working substance should be as close as possible to the fog stage. Then the heat will be transported by drops of warm liquid.
In order to achieve this, it is necessary to observe the main condition - the input in the pipes must have a minimum temperature of 40 and a maximum of 60 ° C.
Vacuum appliances provide an indoor temperature of 2-3 degrees lower than traditional batteries. But the cost of heating the house is reduced by an average of 17%
In the case of an autonomous system, it is difficult to achieve such indicators. In areas of the heating system remote from the source, the coolant will cool very quickly. Output in application pyrolysis boilers with an optimum temperature from 45 to 60 ° C or from 50 to 70 ° C.
In another way, the problem is solved by mounting a single mixing unit in front of a group of vacuum radiators. In this case, the low-temperature level will provide a connection of the heated water with the cooled from the return. The duty cycle in the vacuum radiator is repeated after the condensate is lowered down the inner walls.
Positive and negative qualities of devices
In favor of using radiators that do not contain gases in the cavity, the following arguments are usually given:
- guaranteed absence of such a phenomenon as airing of the system;
- low hydraulic resistance;
- complete absence or minimal corrosion;
- stable heat transfer, because no dirt settles on the inside surface of the case;
- the minimum number of threaded connections, which makes unlikely cases of leakage;
- wide choice of the heat carrier: antifreeze, water, steam, etc.
If we compare these products and the usual water, then in apartments that are heated centrally, the air will not be heated equally. In the second case, the water entering the system heats the entire body of the radiator directly. In the vacuum, the water from the central highway heats only the lower part.
The use of vacuum radiators saves coolant up to 80%. In addition, when the battery is disconnected, the heated gas particles slow down movement, so it cools for a long time.
The remaining sections of the battery receive heat from the evaporated liquid. Due to the fact that the heat transformer has both temperature and heat conductivity lower than that of water, the walls of the vertical sections of the radiator will warm up less.
To ensure the same temperature conditions as in the presence of water batteries, the vacuum radiator must have a large area.
Manufacturers claim that the product section warms up instantly. With a small volume of water in 0.5 liters, one fragment has a heat transfer of 300 watts. It should be noted here that each section, which has become a classic, a cast iron radiator contains 4 liters of liquid.
Savings are particularly noticeable when using antifreeze. The cost of its acquisition will decrease significantly. A small amount of coolant, no need for expensive equipment - the main advantages from the use of vacuum radiators.
The advantage of these devices is the fact that the room warms up more smoothly vertically. According to the measurements, the difference is about 0.5 ° C per each meter of height. In a room with a ceiling height of 2.5 m between the device and the floor, it will be approximately 1.25 ° C.
The effectiveness of vacuum radiators is manifested when using alternative energy sources such as a heat pump, solar panels.
While cast iron batteries can heat the room when the coolant reaches a temperature of at least 65 ° C, 35 ° C is enough for vacuum devices
You should know that if the depressurization of the section occurs due to some circumstances, the vacuum radiator will not work. The reason - pressure indicators inside and outside the case will be equal.
Such a breakdown poses a threat to the well-being and health of people living in the house, because the liquid inside is poisonous.
When is a vacuum radiator advantageous?
Based on the features of the vacuum radiator, it can be concluded that its use in the central heating system will not bring much benefit.
Use of the device is justified when choosing an autonomous heating system. If it is not water that makes the cycle, but an antifreeze liquid, then the cost of the coolant will decrease significantly.
Heating system with vacuum radiators is very effective in tandem with a solar collector. For the cottage is the best modern technology.
Installing vacuum batteries is a rational solution to the issue if a low-capacity boiler is purchased. Such a source will not be able to heat the coolant to the high temperature required for the operation of traditional devices. In the case of a vacuum unit, this is not required. The reaction inside it starts already at 35 ° C.
Country cottages, which the owners do not use for living permanently, warm up for a long time in the cold. Accelerate the vacuum radiator process. The process of heating with his participation occurs quickly, and the heat is distributed evenly.
Product selection rules
With the growing popularity of this high-tech equipment on the market, more and more low-quality counterfeit products are found.
When buying, you should check whether the appropriate certificates and other technical documentation have been attached to the device. It should be remembered that the basic rule of effective operation of the unit is complete tightness.
It is important for the radiator and such a parameter as the amount of coolant in the vertical sections is a lithium-bromide mixture. Large volume can threaten the flow of fluid.
To assess the compliance of the volume you need to focus on the sound that occurs when the unit is rocking. It should resemble a quiet rustle. If, on the other hand, the sound of a flowing liquid is clearly distinguishable, the radiator is likely to be a fake handicraft.
For most of their models, European manufacturers give a guarantee of up to 5 years. Prices for them are directly proportional to the number of sections and they are higher than for water analogues
On products manufactured by factory technology, welding seams have no flaws, unlike units of unknown origin.
Manufacturers with a good reputation cover the case of products with high-quality powder paint. Therefore, the integrity of the paint layer is difficult to break even in contact with the solvent. It is impossible to miss such a moment as the tightness of the filling valve.
The subtleties of installation do it yourself
Installing a vacuum radiator is easy, but to do without alterations, you need to learn a few rules. It is necessary to comply with the recommendations regarding the placement of the unit relative to the wall, floor, window sill.
At the same time, the distance between the radiator and the wall is at least 50 mm, between the device and the floor is from 20 to 50 mm, the optimal distance to the back of the sill is 50-100 mm.
The photo shows the options for connecting radiators. You should know that the inclusion in the heating circuit of other heating devices, along with vacuum reduces its effectiveness
The installation itself is not much different from the tie-in system other types of radiators. The only difference is that the entrance and exit are at the bottom.
The installation of a vacuum unit provides for a chain of consecutive actions:
- Drain the coolant, dismantle the old heating device.
- Perform layout of installation sites.
- Brackets are attached. Test them for stability, durability.
- Mounted ball valves. Through them, the device is connected to the highway. Joints must be sealed using tow or sealant.
- Check the system for tightness.
To improve heat transfer, a sheet of foil can be placed on the wall behind the radiator. In the presence of previously performed insulation, it is necessary to increase the length of the brackets by an amount equal to the thickness of the insulation layer. If the house is insulated, the efficiency of the heating system will increase.
The best manufacturers of vacuum radiators
A wide range of vacuum heaters in the market is not different. Among consumers, the company's products are of particular authority. Energyco. This Russian manufacturer uses for the manufacture of batteries 1.5 mm steel. Users note high-quality performance, good heat dissipation - about 170 kW per item.
Working for the radiator is the pressure from 0.6 to 1.3 MPa. Even with 2 MPa, the device can work, but 5 MPa is very much for it - it starts to break down. The cost of the radiator from EnerdzhiEko considerable, but the demand for it does not fall.
Manufacturer Forevacuum produces vacuum wall and baseboard type appliances. Heat transfer register length of 1 m at a temperature of 50 ° C coolant is 239 watts.
The thermosiphon register is distinguished by its low metal intensity, since its thin-walled case is not designed for high internal pressure. At 50 ° C and using ethanol it is only 0,027 MPa
You can also find Chinese-made radiators on the market. They will have a lower price, but sometimes a dubious quality. When buying, they should be carefully inspected, check the documentation.
Conclusions and useful video on the topic
Familiarity with the design of the vacuum device and the principle of its work:
Some craftsmen create vacuum batteries with their own hands:
There are conflicting opinions about the feasibility of using vacuum radiators. But in some cases, this method of heating can be very effective. The main thing to make sure when buying in their excellent quality and complete security.
Still have questions, found shortcomings or would you like to add this material with your own opinion about vacuum heating radiators? Please leave your comments in the contact box located under the article.