Heating homes: pros and cons of stoves and heaters

Autumn is the time of the first cold, it's raining, it is moist, surely it is good to turn on the heating.

But if not enough, as it is better to warm up? Better a heater or stove? Which of the two is more efficient? Which heat is better?

In fact, from the point of view of the heat produced, at the same temperature environment reached. a source that is the other. After reaching the desired temperature there is a heat better than the other. Heat is energy and energy is all the same regardless of the source that produces it.

So the problem must be approached from a different point of view. At the same time the ignition is better to light a gas stove or a thermofan? Which of the two is more heat? Here, too, has little to do physics. It depends on the type of stove or thermofan in our possession and especially by its efficiency.

Suppose, for simplicity of having an electric heater infrared (those that have the light tubes to understand) that heat primarily by radiation and a thermofan electric (those that emit a jet of hot air) that heat mainly by convection. Let's suppose for simplicity that consume the same energy: 1 kWh (one kilo-watt-hours), that is 1000 watts in an hour. If the two stoves have the same efficiency, or rather the same COP (coefficient of thermal performance), will produce an identical heating. Since usually the electric heaters have a COP of 1, for every kWh of energy consumed will have a warming of 1 kWh, ie 860 kcal corresponding to 3,600 kJ.

Always to make a comparison, if we had 860 liters of water, with the same energy we could take her to a temperature of 15 ° C at a temperature of 16 ° C. Regarding an apartment, since the air has a specific heat of 1,005 kJ / kg K, equal to about a quarter of that of water, with the same energy could raise the temperature of 4 degrees in an environment of 860 kg of air that is in an apartment of about 220 square meters (assuming negligible dispersion). So there is no difference? At constant power consumption there is no difference between the heat produced from the sources or the temperature reached, however, there is a different perception of human warmth and a different effect on the environment as well as psychological.

The irradiation facilities have the ability to not heat the air but the walls and the bodies, as the air itself transparent to radiation, this means using less energy to heat the volumes, and lack of air movement and dust in 'environment and a shorter time to reach the temperature of the facility, for which a lower cost than a traditional system convection. Furthermore, heating the surfaces and not the volumes of air, can be used for heating small areas of the home without heating the entire environment, which however is not possible with a plant air convection.

In systems convection, the air movement creates difficulties both in terms of the homogenization of the environmental heat, since the warmer air tends to rise to the top, that the health due to the presence of dust and particles in suspension potentially harmful to health. The stratification of the air masses in function of temperature, then entails a greater waste of energy due to the greater dispersion through the roof of the housing and through the heating of the upper parts of the walls. Last but not least there is the psychological effect.

The man has always been accustomed to warm up by the fire, so to receive heat from a directional source, a radiant heater is therefore the closest thing to a traditional fireplace from which to receive a warm well-being, let us remember, however, that if we want to quickly heat a volume , just close the door properly and if the environment is clean will be the hot air heating best.

20/11/2011

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Translated via software

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Source:

Italian version of CercaGeometra.it