Comparison Midea D80-15F1(W) vs Midea D50-15F6(D)

The volume of the tank installed in the storage water heater (see "Type"). It is one of the key parameters for such devices. On the one hand, a large tank allows you to keep a large supply of water and reduces the risk that it will run out at the most inopportune moment; this is especially important when water consumption is high, such as in a large family. On the other hand, a volumetric tank correspondingly increases the size, weight and cost of the entire device, requires reliable fastenings (when installed on a wall), and more energy is spent on heating and maintaining the temperature of the water in it. Accordingly, when choosing, it is worth not chasing the maximum volume but proceeding from the actual water consumption and this point of view determining the optimal capacity of the tank.

Some special tables and formulas allow you to calculate the optimal volume of the tank depending on the format of use (washbasin, shower, kitchen sink ...), the temperature of the water used and other parameters. These data can be found in special sources. Here we note that the smallest storage water heaters can hold only 5 litres; such devices are designed for washing, washing dishes for 1 – 2 people and other tasks that do not require a lot of water. The average value is considered to be a volume of 80 – 100 litres, such a tank is quite enough for an apartment in which 3 – 4 people live. In the largest models, the volume is already calculated in cubic metres; such water he...aters are designed, for example, for hotel buildings, showers in sports complexes and swimming pools, and other similar places where a lot of hot water is required.

The highest water temperature provided by the device. The standard temperature of hot water in the water supply is 60 °C, and this value is actually the minimum for modern water heaters: models with more modest rates (usually from 40 °C) are extremely rare. But higher values can be found much more often: for example, water heaters of 75 °C and 80 °C are very popular, and in the most powerful models in this regard, the temperature can reach 95 °C and even higher.

On the one hand, strong heating requires appropriate power (which is especially noticeable in the case of instant electric heaters). On the other hand, the higher the temperature of hot water, the less it is needed for a comfortable outlet temperature, after mixing with cold water; this reduces the consumption of heated water, which is especially important for storage boilers. In addition, many models have thermostats (see "Features").

Also, note that heating to operating values may involve different ΔT (degree of temperature change) — depending on the initial temperature of the cold water. The actual performance of the heater directly depends on ΔT; this moment is described in more detail below, in the paragraphs devoted to performance at different ΔT.

— Open coil. The open coil is made from a high-resistance electrical wire enclosed in a thin insulating sheath. The main advantages of such an element are the heating rate, high efficiency and precise temperature control; in addition, scale is almost not formed on the spiral. And of the shortcomings — a low service life.

— Wet heating element. Wet heater is a metal tube with a heating thread laid in the centre; the space between the tube and the thread is filled with an insulating material with good thermal conductivity. Heating elements heat up more slowly than open coils, have lower efficiency and are prone to the formation of scale on them; on the other hand, their service life is much longer, and in instant heaters, heating elements are not so sensitive to air pockets.

— Dry heating element. A kind of heating element with an improved design: the heater tube is enclosed in an additional shell (most often made of metal with an enamel coating on the outside) and does not come into contact with water, hence the name. Thanks to this, the likelihood of scale formation is reduced, which is especially important when working with hard water. Also, the replacement of such elements is significantly easier than conventional ones. Among their shortcomings can be called a rather high cost.

— Infrared heating element. Tu...bular electric heater of a special design: in the form of a transparent glass tube, in which the incandescent spiral is enclosed. The principle of operation of such an element is somewhat different from a conventional heating element: a significant part of the heating is provided by infrared radiation, which heats not so much the water as the walls of the tank — and heat is already transferred from them to the water. Thus, the water is heated not only at the point of contact with the heating element but also at the point of contact with the walls — which means that the heating is faster and more uniform. Also, note that the IR heater itself is usually "dry"; see above for the advantages of this design. The main disadvantages of such heaters are high cost and relatively short service life.

— Heat exchanger. It is used in gas and indirect heaters (see Water heater type). It is a metal structure heated by burning gas (in gas heaters) or passing inside a heated coolant (in indirect heaters). Usually has a ribbed shape. It is done to ensure the maximum area of contact with the heated water with relatively small dimensions — the larger this area, the more heat is transferred to the water per unit of time and the more efficient the heater is.

- Mechanical. Manual control using rotary knobs and mechanical buttons. Models with mechanical controls are inexpensive, but the control capabilities themselves are quite limited and, as a rule, include only basic functions.

- Electronic. This control is carried out using an electronic unit. Electronically controlled heaters, as a rule, have a wider range of functions than their “mechanical” counterparts; they can be programmed and equipped with a display to indicate various parameters. On the other hand, with all other characteristics being equal, such heaters are much more expensive.

The weight of the device, excluding the water collected (passing) into it.