This paper describes the results of a couple of field measurements and an exergy analysis on the traditional radiant heating system, “grounded Kang” in the northeast region of China. Biomass is one of renewable energies and its utilisation has been challenged all over the world. Exergy analysis can provide us with deep insight about how local or global resources should be consumed, which subsystem and how total system should be designed in order to avoid unnecessary exergy consumption. The authors consider space heating with Kang can be a reference example studying relationship between daily life with biomass and exergy consumption. From such a point of view, the purpose of this paper is to grasp the detailed heating effect of grounded Kang as a radiant heating system and its differences in the characteristics of exergy-consumption process from other biomass-based heating systems.

 The result obtained from this study are followings. 1) Both the room air temperature and the MRT measured were kept within the range form 20 oC to 26 oC. Thermal discomfort was avoided by this traditional heating measure. 2) The amount of primary exergy input for grouned the Kang is 12.8 GJ/week and that for the elevated Kang is 4.6 GJ/week. This difference in primary exergy input between the Kang and the elevated Kang, 8.2GJ/week (=12.8-4.6) means the advances of combustion efficiency and thermal storage effect in the elevated Kang. 3) Exergy efficiency of the grounded Kang based on primary input is 0.034 and the smallest among the three biomass based space heating systems. There is some differences in exergy efficiency between the elevated Kang and air conditioner driven by biomass power generation: the elevated Kang 0.092 and air conditioner from 0.107 to 0.151 corresponding to power generation efficiency from 23 % and rice straw transport distance 1000km to 28 % and rice straw transport distance 100km. 4) PMVs are from 0 to +0.5 in three heating systems, but the MRT in case of air conditioner is from 3oC to 7 oC lower than the room air temperature, because air conditioners do not have radiant heating effect. As a result, there is possibility that cold draft may occur from near windows more frequently in case of air conditioner than the other two space heating systems.

 In case that rice straw transport distance is 100km or less, air conditioner driven by biomass power generation is more efficient than the elevated Kang, if considering the fact that farmers tend to avoid selling their rice straw to an electric power company, residents should use the elevated Kang whose energy performance is superior to the grounded Kang and the briquette of rice straw