Textual main purpose is improving the system about performance evaluation to increase the competition ability objected as GN heating supply company (GNHS).

In this paper, SGN-ring is introduced, some sufficient and necessary conditions which judge a module is FGT-projective module or FGT-injective module are given.

In this paper, a equivalent characterization of GN-rings is given.

Experimental study on operation characteristics of ground coupled heat pump operated in cooling and heating mode

Discussion on approach to the problems of colliery heating design;

Heat-transfer oil furnace heating－-the good way for WBP enterprises saving energy and increasing efficiency;

Identification of dangerous factors and accident preventive measures of urban underground heating pipeline;

Energy saving technology in heat supply and heating and developmental direction of equipments;

Utilizing rubbish-incineration to produce heat for heat supply system;

Study on current heat supply status in residential area of Pingyao as well as questions existed;