As the mercury dips way below freezing point, heating systems become the most sought after appliances. Of all the range of heating systems available in the market, most are developed for indoor heating purposes. One of the few types of heating systems developed exclusively for the purpose of keeping small outdoor spaces warm is the patio heater. You will find them installed in outdoor spaces of restaurants, as well as houses, where they are becoming a regular fixture. Here we peek into the inner workings of these appliances, to know how they provide warmth in outdoor spaces.
'Heat Transfer Through Radiation' is the working principle of these devices. Every material, when heated to specific temperatures, emits heat in the form of electromagnetic waves in the infrared range. Most conventional heaters were based on the principle of heat transfer through convection, which is not as efficient as radiative heat transfer.
What is a Patio Heater?
These devices are designed to heat up small outdoor spaces like patios and home porches. They come in two primary varieties. One is dome shaped and the other is a wall mount type. They are either powered by electrical heating or propane combustion. For outdoor open spaces, dome shaped heaters are the most commonly used ones. They consist of a pole with a dome shaped metal cage mounted at the top.
Most of them are powered by a propane based heating source. There are dials provided for temperature control, with automatic shut down safety mechanism that prevents flaring of the burners fitted inside.
A pole shaped patio heater is connected with a propane gas cylinder through a regulator mechanism. As soon as the heater is powered on and the regulator valve is opened, gas flows through the pole and into the burners placed at the top, below the dome mechanism. The burners start operation, triggered by electric ignition, to heat up the radiant heating element placed above them. As the temperature of the element rises, it starts radiating heat in all directions. Since the dome is covered from above and open only on the sides, it is radiated horizontally and heat loss in the vertical direction is lesser.
This ingeniously designed mechanism ensures that most of the radiated heat is directed into a circular space around the heater. Depending on the wattage of the heater, the intensity of heat radiation varies. The heated element starts emitting infrared waves, which are absorbed directly by the human body, providing warmth. Through installation of multiple heaters, a large outdoor space can be kept warm quite easily. Wall mounted propane based heaters operate on the same principle, and radiate heat directly in front of the instrument panel.
Thus, using a radiant heating element and a dome mechanism, these devices spread heat uniformly. They make for ideal installations to keep outdoor spaces warm in fall and winter. The fact that they are propane based heaters and they radiate heat (instead of relying on convective heat transfer), makes them highly energy efficient appliances. Plus they are portable and sold at reasonable costs. I see no reason why you shouldn't have one installed in your home.