The original definition of CRI_<(C)> estimates the room temperature distribution by taking account of only convection. In this paper, we propose the new concept of radiation distribution coefficient (CRI_<(R)>) to improve the original concept of CRI_<(C)>. We also demonstrate the effectiveness of the new concept of radiation distribution coefficient by applying it to an enclosed space with radiation and convection. The estimated result is compared with the result of the coupled simulation of CFD and radiation and the usefulness of CRI_<(R)> is confirmed.
