This invention generally relates to heat transfer by radiation. More specifically, the present invention relates to a combination of infrared (IR) lamps and reflectors uniquely designed and arranged to realize maximum heat radiation from IR lamps to objects in front with maximum efficiency in terms of energy consumption.
There is known U.S. Pat. No. 5,003,449 related to a light fixture with secondary reflector comprising a secondary reflector located between the primary reflector and the bulb and provided for dispersion of concentrated heat produced by the bulb to maintain the primary reflector at a lower temperature.
There is also known U.S. Pat. No. 4,315,302 related to a quartz light fixture having a closed fixture reflector assembly consisting a lens mounted in front of an outer portion and an inner portion. Reflectors are made from a white aluminum to facilitate intensification of light from a lamp. However, this assembly is provided strictly for lighting purposes only and cannot be used for heating.
A variety of heat radiator units have been available for years, and some have been used in various industrial applications. Traditional room heating systems mostly depend upon convection and conduction for heat conveyance. In the case of convection, heat is transferred to the occupants by bringing the air temperature to the required temperature.
The disadvantages of this method become particularly manifest when the room is occupied for a short period of time, or air changes are frequent. Also, a lot of energy is lost in heating up large volume of air, which takes considerable time. Moreover, when open-flame heating systems are involved, this system takes oxygen from the air and produces water vapour and other combustion products.
In many respects, heating by shortwave infrared radiation differs from other heating systems. This has to do with the high temperature of the radiant source, the directness of energy transfer, and eliminating the need for heating up the surrounding air or unnecessary parts of the room, such as the walls. Short wave infrared obeys the same laws of propagation as does visible radiation, and because of the compactness of the lamp, it can be accurately directed toward the objects to be heated, although it does require a direct line of sight between the source and the objects.
There are situations in which extra radiation is needed to create a thermally comfortable environment. One might think of churches, terraces, stadiums, etc., where no permanent heat is needed, but heat can be provided when it is required.
This heat can take one form of infrared radiation, generated by the short-wave IR lamps. This radiation is almost identical to solar radiation, but this system does not produce ultraviolet radiation (UV). The moment such a heater is turned on, the radiation is produced immediately and there is no heat when the radiator is turned off, thus facilitating so called instant zone heating.
The extra heat that is received by the people is called irradiance and is expressed in watts per squared meters (W/m2). The solar radiation reaching a horizontal plane at sea level on a bright day is about 800 to 900 W/m2.
The amount of extra heat that is needed depends on:
The ambient air temperature
The clothing people are wearing
The activity of the people
The air velocity.
The present invention allows to solve existing problems comprises heat radiator unit including a base, a primary reflector mounted on the base. Primary reflector having an elongated body comprising side walls upstanding outwardly from the base and end walls Primary reflector is adapted to accommodate a high power heating lamp, wherein said lamp is accommodated within said primary reflector by means of an elongated gap formed between lateral edges of the side walls of said primary reflector adjacent to the base. A secondary reflector mounted on the base. Secondary reflector having generally an elongated configuration, and including an inner surface and an outer surface, the secondary reflector""s inner surface is facing the elongated gap of the primary reflector and said the surface is facing said base. The advantage of such arrangement allows the secondary reflector is adapted to reflect all lost radiation emitted from said lamp through said gap towards the base, thus facilitating prevention of overheating of the base and increasing efficiency of the heat radiator assembly. Primary and secondary reflectors are formed from a material adapted to withstand the high power heat generated by the lamp and to emit an eye-friendly worn colour. The assembly of the present invention is housed in an open enclosure or housing adapted to withstand thermal expansion and to ventilate and evacuate the high power heat generated by the lamp.
The heat radiator assembly of the present invention is more efficient and more economical to operate than the prior art stacked heat radiator. It comprises an IRA HeLeNe lamp (made by PHILIPS) and an aluminum lamp holder which is designed to hold the lamps. The symmetric or asymmetric reflector from tempered aluminum provides a constant and very high reflectance of approximately 98%.
In one specific embodiment of this invention, each reflector is embossed with a unique pattern designed to promote the heat irradiance efficiency of the radiator and ensure structural integrity of the unit.