Selection Criteria For Convectors - Overview | Heating and heat supply 2023

2023 Author: Douglas Hoggarth | [email protected]. Last modified: 2023-05-24 11:23

The device and principle of operation of the convector
Comparative characteristics of three convector models
How to choose a convector
Finally - installation and operation

Selection criteria for convectors - overview

Quiet, flat and compactly located on the wall - this type of heater invariably attracts the eye of homeowners who are concerned about the problem of additional heating of their home. The convectors displayed on store shelves are full of logos of famous brands, their manufacturers vying with each other promise long warranty periods, there are seasonal discounts - it is very, very easy to get confused, succumbing to the persuasion of sellers and as a result a device that is not quite suitable for its characteristics. The choice should be deliberate, and the heater itself should be effective and convenient for households. And in this case, an overview of convectors, their characteristics, device and selection rules will be very useful.

The device and principle of operation of the convector

The design of the convector is very simple - a flat body, inside of which there is an electric heating element and a thermostat, the regulator of which is brought out to the external panel. The convector body is made of 0.8 mm thick metal sheet, painted with epoxy-polyester or powder paint. The electric heating element can be one of three types: tape (needle), tubular or monolithic.

The needle-ribbon heating element is a narrow dielectric plate pierced on both sides by rows of protruding loops of chromium-nickel wire. In modern models of electric convectors, tape heating elements are rarely used - with a low cost price, almost complete absence of thermal inertia (heating and cooling of a heating element occurs in a few seconds) and a high heating temperature, their wire loops are too fragile. In addition, the tape heat element is not able to quickly heat the air, because the tape heating element does not have its own ribbing - it heats the convector body, due to the heating of which air convection occurs.

Tubular heating elements (heating elements), along the length of which are installed many aluminum fins, have retained their popularity for several decades. The efficiency of heat transfer from the heating element to the air is directly related to the number and location of fins. Positive characteristics of heating elements: lower temperature of the tube surface compared to the heating temperature of the nichrome thread located inside; longer service life, compared to the tape element; admissibility of installation in humid rooms (IP24). Their disadvantages: the temperature expansion of the steel tube of the heating element and the aluminum fins is different, therefore, crackling is heard during operation; the rib plates do not fit tightly to the surface of the steel tube of the heating element and during operation this gap will only increase, increasing the heat loss of the device.

Monolithic heating elements are arranged differently than classic tubular ones - a nichrome thread with a dielectric filling is placed in a cast aluminum case, and the ribbing is its integral part. The advantage of a one-piece body with ribbing is that there is no difference in thermal expansion, which is present in the operation of heating elements with a steel tube and plate fins made of aluminum. The operation of solid heating elements is noiseless, intermediate heat losses are minimal, and the relatively low heating temperature of the fins' plates allows to reduce the heating temperature of the convector body. Modern models of monolithic heating elements have rough (shagreen) surfaces, which is achieved by introducing a special additive into the aluminum alloy - roughness increases the efficiency of heat transfer, contributing to radiation heat transfer between the heating elements plates.

Modern convectors are equipped with a mechanical or electronic (programmable) thermostat and an overheating sensor without fail. The accuracy of setting the electronic thermostat is 0.1 ° C, the mechanical one is 1 ° C - electronic temperature control allows you to set and maintain the most comfortable temperature in the room with less energy consumption (its savings will be about 3%). The temperature range allowed in the thermostat setting is from 5 to 30 ° С.

The principle of operation of convectors is based on different densities of cold and warm air - denser cold air is collected in the room near the floor, warm air tends to the ceiling. The cavity of the flat body is equipped with two lattice slots located in its lower and upper parts - cold air enters the device, heats up on contact with the heating element located in the lower part of the body of any convector, becomes less dense and rises to the ceiling.

The hollow body of the convector acts as a kind of wind tunnel, in which the air draft is caused by its heating. The process of entering cold air, heating it and lifting it up, entering a new portion of cold air, etc. (convection) - continues during the entire operation time of the convector. By the way, the slots at the top and bottom of the device are not parallel to each other - the upper one is located at an angle to the floor plane so that the heated air rises to the ceiling not in a straight line, but in a parabola, which makes it possible to increase air heat exchange. On average, heating the air in the room to the optimal temperature using a convector will take about 20 minutes, provided it has sufficient power and the outside temperature is not too low (not lower than -5 ° C).

The produced convectors are divided into two groups - floor (wall) and skirting, the height of the models of the first group is about 450 mm, the second - no more than 200 mm. At a low height, the length of skirting electric convectors can reach 2,500 mm, these devices can be conveniently installed under window openings, especially low ones. Low height with considerable length allows skirting convectors to warm up well the lower layer of the air atmosphere in the room, but their considerable length creates difficulties when choosing a place for their installation.

Comparative characteristics of three convector models

For an overview of the characteristics, the convectors of the popular brands "Noirot", "Ballu" and "Nobo" with the same power of 1500 W were selected.

specifications Noirot Spot E-3 1500 Ballu Plaza BEP / E-1500 Nobo C4E15 power supply and power consumption voltage, V 220-230 220-240 220-230 frequency Hz 50 50 50 maximum power, W 1500 1500 1500 operating modes, power consumption number of operating modes 1 (*) 2 1 first mode, W - 750 - second mode, W - 1500 - control room thermostat electronic electronic electronic overheat protection there is there is there is rollover shutdown no there is no control of heating modes mechanical mechanical mechanical light indication when the mode is turned on there is there is there is led display no there is no General characteristics type of shell vertical monoblock vertical monoblock vertical monoblock body material metal tempered glass and metal metal primary colors White gray the black White gray heating element type solid aluminum solid aluminum sintered heater with ribbing type of instalation wall / floor wall / floor wall moisture protection IP 24 IP 24 IP 24 electrical protection class of the case II II II wall mounting kit there is there is there is removable legs (wheels) included no (additional option) there is no (not included) for space heating, m ² 15-20 15-20 15-20 size WxHxD, cm 58x44x8 82x45.2x10.5 92.7x40x5.5 Weight, kg 5.4 9.45 6.6 brand owner Noirot, France Ballu Industrial Group, China Glen Dimplex Nordic AS, Norway country of origin France China Norway warranty, years 6 2 five estimated service life, years 20 fifteen 20 other options frost protection there is no there is remote control control no there is no timer no there is no average cost, rub. 4100 4200 4100

Analysis of convector models based on the information given in the table:

the European models of the Noirot and Nobo brands are less attractive in design and performance than the Chinese model Ballu. The latter also benefits from the position of functionality - this convector is controlled by the remote control, while European models have only mechanical control;
the “Ballu” and “Noirot” models are equipped with a one-piece silumin (aluminum alloy) heating element, which is more efficient and quiet in operation than the cermet ribbed heating element in the Nobo design, the operation of which will be accompanied by a characteristic crackling for the reasons described above;
two preset operating modes (with half and full power) are present in the functions of only one device - the Ballu convector. It should be noted that this type of heaters, by and large, does not need preset power modes - their task is to maintain a given temperature range in the room, using the power required for this;
only the Ballu model is equipped with a timer for 8 hours, which allows you to set the device to turn on after a certain period of time;
the "frost protection" function, in which the room temperature will be maintained at least + 5 ° С, is available only for the described devices of European brands;
the longest warranty period is provided by European convector manufacturers;
Models of the Noirot and Ballu brands allow both wall and floor installation of devices, moreover, the necessary set for floor installation is included in the standard set of the Ballu convector and, most often, is not included in the standard equipment of Noirot. It should be noted that the Noirot heater is not equipped with a rollover shutdown sensor, while the Ballu convector has such a sensor. The described device of the Nobo brand, with equal power with the other two models participating in this review, differs in the greatest length and smaller thickness (depth), and therefore its design does not allow for floor installation.

Noirot Spot E-3 1500

(*) - In the absence of power modes, the Noirot convector is equipped with preset modes "comfortable" and "economical". The first one is intended for use in the daytime; when activated, the device will maintain a constant temperature level in the room, which was set by the user. "Economy" mode is intended for operation of the heater at night - when activated, the convector maintains the room temperature level 3 ° C below the "comfortable" level.

Ballu Plaza BEP / E-1500

Conclusion: It is difficult to make an unambiguous choice among the described models and brands of convectors, given that their cost is almost the same. From the point of view of design and remote control capabilities, the Ballu model is attractive, but from the point of view of reliability and safety, the advantage of the French brand Noirot is undoubted, therefore the Noirot Spot E-3 1500 model is recognized according to the survey as the most successful solution to heating problems using a convector …

Nobo C4E15

How to choose a convector

The power when choosing a model suitable for this criterion depends on the thermal characteristics and the size of the room in which the device is supposed to be installed. If the convector is used as an additional source of heating in the cold season or in the off-season, then its power is calculated by multiplying the volume of the room by 25 W / m ², if the convector is the only source of heat, then the volume must be multiplied by 40 W / m ². For example, for auxiliary heating of a room with an area of 19 m ² with a ceiling height of 2.7 m, i.e. volume of 51.3 m ³, a convector with a capacity of at least 1285.5 W is required (19x2.7x25 = 1285.5). Those. for a room with a volume of 51.3 m ³ the optimal choice would be a 1500 W device, with a small power reserve in case of severe frosts.

When choosing, preference should be given to the brands of the largest manufacturers that provide long warranty periods not from scratch - their products really have high performance characteristics that do not change over many years of using the device. Make sure that this convector model must be equipped with an electronic thermostat, an overheating sensor and a tip-over function for floor-standing appliances. Convenient will be control from the remote control and the presence of a timer that allows you to set the switching on of the convector at a certain time. Among the types of heating elements with which convectors are equipped, the best option would be a one-piece aluminum element.

For heating rooms with a high level of humidity, such as a bathroom and a kitchen, convectors with a moisture protection class of at least IP 24 will be needed. However, direct contact of convection heaters with water is not allowed!

Of course, when inspecting the model offered by the seller, its case should not have any dents and scratches, paint stains, sharp edges and geometry violations. All screws holding the housing elements together must be flush. Any external defects indicate poor assembly quality of the device, damage caused during transportation.

When choosing a convector, you should know that:

any convection electric heater dries air and no "improvements", except for equipping the device with a container with evaporated water (water must be topped up periodically!), does not exist;
air convection due to its heating will inevitably contribute to the rise and constant presence of dust in the atmosphere of the room, its accumulation between the plates of the heating element. Any statements like “this convector model does not accumulate dust” are not true;
The efficiency of any electric heating device is close to 100%, so you don't need to take on faith statements like "The efficiency of this convector is higher than that of the others."

Finally - installation and operation

When installing the convector's mounting frame on a wall and when installing legs (wheels) on its body, follow the manufacturer's instructions for the given model of the device. The place for installing the device should be chosen with great care: the minimum distance from the floor to the lower edge of its body is 150 mm; from side walls to any object or wall - 250 mm; from the top edge to any object above it - at least 450 mm. Failure to comply with these requirements, as well as full or partial closure of the housing of a working convector with some material, will trigger the overheating sensor and turn off the heating function. Accordingly, it is absolutely impossible to install a "high" convector under window openings and dry things on its body! Only skirting convector models are suitable for installation under windows.

Periodically, it is necessary to remove dust from the external panels of the device with a damp cloth, after turning it off and making sure that the case is cool. To remove dust from the heating element, use a vacuum cleaner with a short, narrow nozzle.