An infrared heater or heat lamp is a body with a higher temperature which transfers energy to a body with a lower temperature through electromagnetic radiation. No contact or medium between the two bodies is needed for the energy transfer. Infrared heaters can be operated in vacuum or atmosphere. Source: https://en.wikipedia.org/wiki/Infrared_heater
Heat lamps are commonly used in shower and bathrooms to warm bathers and in food-preparation areas of restaurants to keep food warm before serving. They are also commonly used for animal husbandry. Lights used for poultry are often called brooding lamps. Aside from young birds, other types of animals which can benefit from heat lamps include reptiles, amphibians, insects, arachnids, and the young of some mammals.
The first experiment to test the heating efficiency of infrared used a prism to catch the sunlight and direct and disperse the colors down onto a table, the second was a small panel of cardboard with a slit wide enough for only a single color to pass through it and finally, three mercury-in-glass thermometers. Through his experiment Herschel found that red light had the highest degree of temperature change in the light spectrum, however, infrared heating was not commonly used until World War II.
After the war, infrared was used extensively in the motor industry - Why?
Fig 1. Anyone for a nice hot kebab?
IR heaters can satisfy a variety of heating requirements, including:
Extremely high temperatures, limited largely by the maximum temperature of the emitter
Fast response time, on the order of 1–2 seconds
Temperature gradients, especially on material webs with high heat input
Focused heated area relative to conductive and convective heating methods
Non-contact, thereby not disturbing the product as conductive or convective heating methods do
Thus, IR heaters are applied for many purposes including:
Heating systems
Curing of coatings
Plastic shrinking
Plastic heating prior to forming
Plastic welding
Glass & metal heat treating
Cooking
Warming suckling animals or captive animals in zoos or veterinary clinics
Hot Yoga fitness classes to mitigate respiratory issues posed by convection heating[16]