A good ventilation system creates an influx of fresh air masses from the street and the discharge of waste into the external environment. In the cold season, a lot of heat is lost, low-temperature air enters the room from the street. In order not to spend fuel on heating the street, homeowners often consider connecting a recovery device. Ready-made appliances have a high price, but you can make an effective recuperator for a private house with your own hands.
What is a recuperator
Devices transfer heat from already heated air masses to cold ones coming from the external environment.
There are several types of heat exchangers for the heat exchanger. Lamellar and tubular recuperators are most widespread.
The economic effect of the use of the device is determined by investments in its installation and maintenance, as well as the planned duration of operation.
Varieties of recuperator
Devices differ in design, mechanism of operation, the nature of the movement of air.
By type of coolant movement
Different devices have different airflows. In direct-flow models, the supply and exhaust flows go in the same direction parallel to each other. In countercurrent devices, their vectors are inverse to each other. For devices with cross current - directed at right angles.
According to the design and principle of operation of the heat exchanger
One of the common types of devices is rotary. The device of such a recuperator includes a sealed case and a drum placed inside, moving thanks to an electric motor. When the rotor spins, it falls into the region of warm air masses, then into the cold zone. In the process, the drum is then heated, then cooled. This type of operation of the recuperator provides heat transfer to the air coming from the external environment.
In a plate device, the heat exchange cartridge consists of a large number of flat elements of a rectangular, square or other shape. Between adjacent components there is a distance of several millimeters. When heated air passes through the plate structure, heat is transferred to the elements, which then give it to the cold stream. Heat transfer is realized due to the parallel heating and cooling of the plates.
If you want to assemble a recuperator with your own hands, it is better to give preference to the plate version due to its simplicity.
Advantages and disadvantages
Different models of devices differ in their characteristic features. For example, devices with a rotor are highly efficient, are not subject to icing in winter, and are able to control air humidity (within certain limits). Their disadvantages include a bulky structure with a large number of moving elements, which increases the likelihood of failure and increases the need for maintenance. In addition, they work quite noisily.
Lamellar models often attract attention because of the low price, compactness, simple structure without moving elements. But in cold weather, under the influence of condensate, the plates undergo freezing. This forces us to look for ways to combat this phenomenon. The most effective of these is to install a cellulose cassette that absorbs excess fluid. In this case, water from the condensate is sent to the home and humidifies the air. Such a device works in all weather conditions.
Recuperator selection rules
When considering a model for acquisition, it is necessary to evaluate how much its characteristics correspond to the data of the room in which it is planned to install the device (height, area, desired exchange rate). To calculate these parameters, it is advisable to contact a professional, since this procedure requires a good knowledge of building codes and laws of movement of air flows, and it will be expensive to replace the device with an error in the calculations.
It is important to determine how much air in cubic meters should enter the room in 1 hour. According to sanitary standards, the minimum value is 30 m2 per person. In reality, this indicator, associated with the performance of the device, will be greater due to the large number of costs: duct resistance, the size of the premises served, etc.
When choosing, attention is also paid to the sensitivity and reliability of the automation unit. Many modern devices are equipped with some additional functions: regulation of the power of ventilation devices, air flow pressure (the amount of carbon dioxide in the hood is estimated), etc.
The degree of noise generation of the device should be estimated.
Some devices are hung on the wall, others are mounted on the floor. There are horizontally located models. Suitable design is selected depending on the installation location and system parameters.
DIY recuperator manufacturing
An air recuperator for a private house can be made with your own hands from different materials. Sometimes enthusiasts collect devices, taking sewer pipes as a basis. You can make a recuperator from foil. Simplicity of execution and at the same time efficiency differ in plate devices. Blanks for flat elements can be aluminum or made of polycarbonate.
When making a recuperator for an apartment with your own hands using sheet aluminum, it is preferable to take thin raw materials - in this case, heat transfer is more efficient. In addition to sheets of metal, a self-made recuperator requires the preparation of materials and tools:
- mineral wool 2-3 cm;
- wooden slats in 2 mm thick and 10 - wide;
- plywood sheets for the body;
- hermetic and adhesive compositions;
- fan;
- 2 pairs of flange elements (for tube section);
- hardware.
The height is adjusted in accordance with the total number of plates and their thickness when bonding with rack elements. The diagonal parameter is made identical to the width of the heat exchange element.
Schemes and drawings
Do-it-yourself drawings for the recuperator include a blank for the plate. The side of the square is usually made 0.2-0.3 m. The total number of plates should be at least 80. For them, also prepare rails according to the dimensions of the sides of the square. They are coated with an oil-based compound and, with glue, connected to the inside of each plate. Only one metal square is left without a rail.
Components connect to each other. It is advisable to alternate horizontally and vertically located plates so that each is at right angles to the neighboring ones. This increases the efficiency of the device. A square that is not framed is placed on top. The slots must be filled with a sealing compound.
They make flange fasteners and place the structure in a prefabricated case. The heat exchange element must abut the corners against the side walls, like a rhombus. Holes are made in the device for flange parts, and in the lower part there is a hole for removing condensed moisture through a hose. Then a homemade air recuperator is covered with mineral wool. Connect the device.
Power calculation
The performance of the device in cubic meters per second can be calculated if the required by the standards volume of air flow per person is known. If the first value is denoted by the Latin letter Qand the second L, the calculation formula will take the form:Q = L * 0.355 * (tcom - tst)where:
tcom - required room temperature;
tst - the value of the indicator on the street.
To find the efficiency of the device, you need to know 3 temperature indicators: t1 - outdoors, t2 - the parameter of the air entering the home after passing through the device, t3 - domestic air before recovery. Then the efficiency will be equal (t2 - t1) / (t3 - t1).
The use of recovery devices helps minimize the flow of warm air from the room to the street during the cold season. Independent manufacture of the device will cost less than buying a ready-made one, but modern industrial recuperators are equipped with a large number of additional options.
