Heat transfer from radiators and their other parameters

What parameters should pay attention when buying a heating battery? Generally, what are they? Which is better - traditional cast iron products, light aluminum or strong steel? How to reduce or increase the heat transfer of heating devices? Let's try to answer these questions.

Such different heating systems

Dear reader, we should immediately discuss one very important point. A bad radiator can be called only one that does not correspond to the characteristics declared by the manufacturer. But such parameters as material, heat capacity, dimensions and tensile strength should be evaluated negatively or positively - only for specific conditions.

Let's try to explain with examples.

• For an autonomous system operating from a solid fuel boiler, the internal volume of the section and its thermal capacity are important. The more of these parameters, the better: they mean that it will not be cold between the kindling in the house. Hence the popularity of cast iron batteries among owners of private houses in non-gasified villages.

By the way: instead of massive batteries, a heat accumulator connected to the circuit can be used to save heat - a large heat-insulated tank with water.

• Aluminum is good for autonomous systems with gas, diesel and electric boilers for heating. A small internal volume, a modest section price and a large area of ​​finning will be very useful. But high strength and the ability to transfer significant temperatures to the material seems to be no good: typical parameters of an autonomous heating circuit are 70 / 50С with a pressure of 1.5 - 2 atmospheres.

• The scope of steel registers - rooms connected to central heating, in which considerable attention is paid to design. Steel has the highest resistance to hydraulic pressure and is able to withstand strong heat, but can not boast of good heat transfer per unit of internal volume.
• Finally, bimetallic products combine the strength of a steel core with a high thermal conductivity of the aluminum sheath, which allows them to be equipped with advanced fins. They are an excellent choice for central heating systems where the need for heat is high enough.

Key parameters

So, what options should I look at when buying?

1. On the mass of the section and its internal volume. They are directly related to its heat capacity.
2. Operating temperature determines the ability of the battery to carry overheating in the DH system.

It is worth clarifying: in general, the temperature of the coolant is legally limited to 95 ° C. However, under certain circumstances (for example, when operating the elevator assembly with the nozzle removed and the suction plugged out), there may be 120 and 130 degrees.

1. A high working pressure means that a water hammer with fast filling of the circuit will not cause damage to the section and will not pull out the pin or plug.

1. High heat dissipation of the heating radiator in terms of section with satisfactory other parameters will be a definite advantage. It is clear that the endless rows of sections are unlikely to please the owner with their appearance.
2. The center distance allows you to increase the notorious heat transfer section, sacrificing compactness, or, conversely, place a compact battery under a high panoramic window.
3. Finally, the moderate cost will also be a definite plus.

Research samples

Let's get acquainted with several products of different types presented on the modern Russian market.

MS-140M-500

Nuance: manufacturers indicate the heat transfer section at Dt (delta temperature between the coolant and the room) at 70C. The real value of this parameter most of the heating season is noticeably less.

Warmica Lux 70/500

Harmony A40 1-500 KZTO

Under this name is hidden tubular all-welded register of Russian production.

Note: for the section in this case we accept one register pipe. It is clear that the all-welded product does not understand.

Reefar Monolith

Another non-separable product from the domestic manufacturer is a bimetallic heating device from the company Rifar.

Please note: when installing bimetallic radiators with your own hands, it is strongly recommended to use only steel pipes. What is the reason for the instruction - it is easy to understand: to combine in the general circuit the strongest bimetallic heating device and the plastic pipe, which will break already at 10 atmospheres, is irrational.

Adjustment

What to do if the house is too hot or, on the contrary, too cold?

Radiator Throttling

A radiator that gives off too much heat is supplied with a choke - a regulator of the capacity of the liner.

As always, there are a number of subtleties.

• The throttle is adjusted with a minimum change in its position with long (at least half an hour) pauses for temperature stabilization.
• Instead of a choke, a thermostatic head is often used. It is good in that it is able to adjust its capacity automatically, depending on the degree of heating of the air in the room.

• Only a heater equipped with a jumper between connections can be throttled in the central heating system. Otherwise, valves will regulate the permeability of the entire riser with the corresponding consequences for your relations with your neighbors.

Elevator node setup

In a private house, powered by a heating main, the role of a junction with the highway is performed by an ordinary elevator unit - the same as in an apartment building, but with a smaller diameter of stop valves.

Adjustment can be done in two ways.

1. Increase and decrease the diameter of the nozzle - the standard method of adjusting the parameters of the heating system. Note: its dimensions should be consistent with the organization that sells you the heat.

1. In addition, the amount of heat remaining in the house can be reduced by reducing the differential in the elevator. For this purpose, the inlet pipe closes the inlet valve with continuous control of the pressure of the return pipe through the pressure gauge. Reduce the differential should be no more than 2 meters (0.2 kgf / cm2) at a time.

Increased radiator heat output

What to do if it's cold at home? The most obvious solution is to increase the length of the radiator, installing additional end sections. Heat transfer will grow, but not quite linearly: extreme sections are always noticeably colder than liner.

Installation on the jumper in front of the valve radiator when it is closed will redirect the coolant from it to the section, thereby slightly increasing the heat flux from the heater.

Note: at any time, the battery must have the valves open either on the liner or on the jumper. Having closed all the valves, again, you automatically doom yourself to a meeting with very dissatisfied neighbors.

If the beginning of the radiator is markedly different in temperature from the end sections - perhaps it needs washing. For this purpose, in the summer, with the heating discharged, a conventional ball valve is installed in the lower blind plug; a garden hose is used to discharge water into the sewer.

Finally, for a more uniform heating of the sections, it is better to choose not one-sided, but two-way bottom connection of the heater. Moreover, it will always be heated along the entire length - the flow of water through the lower collector will not allow it to silt. Washing can be forgotten for decades.

Conclusion

We sincerely hope that our advice and recommendations will help the reader in choosing and setting up heating equipment for his home.

As always, additional information can be found in the attached video. Successes!