A heat transfer system having a radiant source (108), a first heat exchanger (112) configured to permit a first fluid (114) to flow therethrough, and a thermal shield (110) configured to provide controlled radiative heat from the radiant source to the first exchanger. The radiant source is a flame. The thermal shield is a second heat exchanger configured to permit a second fluid (116) to flow therethrough or a non-contact thermal shield fabricated from a material arranged to provide controlled radiative heat exposure from the radiant source to the first exchanger. Oxy/coal combustion systems are also disclosed.