Heat dissipation of heating radiators table — Climate in the house

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The main cri­te­ria for choos­ing devices for heat­ing hous­ing is its heat trans­fer.

This is a coef­fi­cient that deter­mines the amount of heat gen­er­at­ed by the device.

In oth­er words, the high­er the heat trans­fer, the faster and bet­ter the house will be heat­ed.

How much heat is needed for heating?

how much heat is needed in the house

To accu­rate­ly cal­cu­late the required amount of heat for a room, many fac­tors must be tak­en into account.: cli­mat­ic fea­tures of the area, the cubic capac­i­ty of the build­ing, pos­si­ble heat loss of hous­ing (the num­ber of win­dows and doors, build­ing mate­r­i­al, the pres­ence of insu­la­tion, etc.). This cal­cu­la­tion sys­tem is quite labo­ri­ous and is used in rare cas­es..

Basi­cal­ly, the cal­cu­la­tion of heat is deter­mined on the basis of the estab­lished indica­tive coef­fi­cients: for rooms with ceil­ings not high­er than 3 meters, 10 m2 1 kW of ther­mal ener­gy is required. For the north­ern regions, the fig­ure increas­es to 1.3 kW.

For exam­ple, a room with an area of ​​80 m2, for opti­mal heat­ing requires 8 kW of pow­er. For the north­ern regions, the amount of ther­mal ener­gy will increase to 10.4 kW

Heat dissipation is a key performance indicator

The heat trans­fer coef­fi­cient of radi­a­tors is an indi­ca­tor of its pow­er. It deter­mines the amount of heat released over a cer­tain peri­od of time. The pow­er of the con­vec­tor is affect­ed by: the phys­i­cal prop­er­ties of the device, its type of con­nec­tion, the tem­per­a­ture and speed of the coolant.

The pow­er of the con­vec­tor, indi­cat­ed in its data sheet, is due to the phys­i­cal prop­er­ties of the mate­r­i­al from which the device is made, and depends on its cen­ter dis­tance. To cal­cu­late the required num­ber of radi­a­tor sec­tions for a room, you will need the area of ​​u200bu200bhousing and the heat flux coef­fi­cient of the device.

sample calculation table

Cal­cu­la­tions are made accord­ing to the for­mu­la:

Num­ber of sec­tions = S/ 10 * ener­gy fac­tor (K) / heat flow rate (Q)

Exam­ple: It is nec­es­sary to cal­cu­late the num­ber of alu­minum bat­tery sec­tions (Q = 0.18) for a room with an area of ​​50 m2.

Cal­cu­la­tion: 50 / 10 * 1 / 0.18 = 27.7. That is, 28 sec­tions will be need­ed to heat the room. For mono­lith­ic devices, for place Q, we set the heat trans­fer coef­fi­cient of the radi­a­tor and as a result we get the required num­ber of bat­ter­ies.

If con­vec­tors are installed near sources that affect heat loss (win­dows, doors), then the ener­gy coef­fi­cient is tak­en from the cal­cu­la­tion — 1.3.

For heat­ing, radi­a­tors are used: steel, alu­minum, cop­per, cast iron, bimetal­lic (steel + alu­minum)and all of them have a dif­fer­ent heat flux due to the prop­er­ties of the met­al.

number of sections in the table

Comparison of indicators: analysis and table

In addi­tion to the mate­r­i­al from which the device is made, the cen­ter dis­tance affects the pow­er fac­tor — the height between the axes of the upper and low­er out­lets. Also the val­ue of ther­mal con­duc­tiv­i­ty has a sig­nif­i­cant effect on the effi­cien­cy.

Radi­a­tor type Cen­ter dis­tance (mm) Heat dis­si­pa­tion (KW) Heat car­ri­er tem­per­a­ture (0FROM)
Alu­minum 350 0.139 130
500 0.183
Steel 500 0.150 120
Bimetal­lic 350 0.136 135
500 0.2
Cast iron 300 0.14 130
500 0.16
Cop­per 500 0.38 150

Factors that affect performance

Production material

types of batteries

Cop­per and alu­minum con­vec­tors have the high­est heat trans­fer. The low­est pow­er fac­tor is observed in cast iron bat­ter­ies, but it is com­pen­sat­ed by their abil­i­ty to retain heat for a long time.

The effi­cien­cy of the effi­cien­cy is affect­ed by the cor­rect instal­la­tion of heat appli­ances:

  • Opti­mal dis­tance between floor and bat­tery — 70–120 mm, between the win­dow sill — at least 80 mm.
  • Manda­to­ry pro­vi­sion air vent instal­la­tion (Crane Mayevsky).
  • Hor­i­zon­tal posi­tion heat appli­ance.

Radi­a­tors with the best heat dis­si­pa­tion:

Mate­r­i­al Mod­el, man­u­fac­tur­er Rat­ed Heat Flux (KW) Cost per sec­tion (rub)
Alu­minum Roy­al Ther­mo Indi­go 500 0.195 700.00
Rifar Alum 500 0.183 700.00
Elsotherm AL N 500x85 0.181 500.00
Cast iron STI Nova 500 (sec­tion­al type) 0.120 750.00
Bimet­al Rifar Base Ven­til 500 0.204 1100.00
Roy­al Ther­mo Piano Forte 500 0.185 1500.00
Sira RS Bimet­al 500 0.201 1000.00
Steel Ker­mi FTV(FKV) 22 500 2.123 (pan­el) 8200.00 (pan­el)

Placement of radiators

placement of radiators in the house

There are the fol­low­ing con­nec­tion types:

  1. Diag­o­nal. The sup­ply pipe is mount­ed to the con­vec­tor on the top left, and the out­put pipe is on the right from below.
  2. Lat­er­al (uni­lat­er­al). The sup­ply and return pipes are attached to the heat appli­ance on one side.
  3. Low­er. Both pipes are brought to the bat­tery from below, from oppo­site sides.
  4. Upper. Pipes are mount­ed to the upper out­lets of the heat appli­ance, on both sides.

The most effec­tive way is a diag­o­nal con­nec­tion, which allows the device to heat up even­ly. With a small num­ber of sec­tions, you can increase the pow­er through the side con­nec­tion.

If there are more than 15 sec­tions of one radi­a­tor, then this scheme will be inef­fi­cientsince the far side will not warm up to this extent.

battery heat dissipation

How to improve heat dissipation

The indi­cat­ed pow­er fac­tor of the con­vec­tor in its data sheet takes place, almost under ide­al con­di­tions. In fact, the mag­ni­tude of the heat flux is some­what reduced, and this is due to large heat loss­es.

heat dissipation screenFirst of all, to increase the coef­fi­cient, it is nec­es­sary to reduce heat loss — to car­ry out work on the insu­la­tion of the house, pay­ing spe­cial atten­tion to the roof, since about 70% of warm air and win­dow and door open­ings go through it.

It is advis­able to install reflec­tive mate­r­i­al on the wall behind the heat appli­ance.to direct all use­ful ener­gy into the room.

When installing a heat pipe, pref­er­ence should be giv­en to met­al pipessince they also car­ry out heat exchange, respec­tive­ly, the effi­cien­cy increas­es sig­nif­i­cant­ly.

Sum­ming up, it should be not­ed that cop­per, bimetal­lic and alu­minum radi­a­tors have the best heat dis­si­pa­tion. The for­mer are quite expen­sive and are rarely used.

Based on the man­u­fac­tur­er’s declared radi­a­tor pow­er, it can be con­clud­ed that bimetal­lic heat appli­ances are supe­ri­or to alu­minum ones..

How­ev­er, in prac­tice, alu­minum appli­ances give off more heat, since the steel that is part of the bimetal­lic con­vec­tors has a high ther­mal con­duc­tiv­i­ty.which means it cools down in a short­er peri­od of time.


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