| Title |
Level Dynamics and Control of the Solution in the High Temperature Generator of an Absorption Chiller |
| Authors |
신영기(Younggy Shin) ; 곽민수(Min Soo Kwak) ; 조현욱(Hyun Wook Cho) ; 남상철(Sang Chul Nam) ; 정진희(Jin Hee Jeong) |
| Keywords |
흡수식 ; 동특성 모델 ; 용액펌프 ; 액위제어 Absorption ; Dynamic model ; Solution pump ; Level control |
| Abstract |
In an absorption chiller, solution is circulated by a solution pump with an inverter to vary flow rate depending on operating conditions. For optimal operation, the solution level in the high temperature generator should be kept constant. However, a sensor for measuring continuous level is not available because of varying solution concentration. Instead, level switches are used and hence feedforward control associated with limit checking is a common practice. In the study, inverter frequencies are estimated from a dynamic simulation model and pump performance. Designed frequencies are compared with those implemented in real chillers. It was found that the frequencies used in real chillers are larger than those needed in circulation flow rates. It was intended to prevent system shut-off caused by dry-out. However, it is necessary to minimize the excessive frequency setting in order to reduce frequent pump stops and the range of solution level for continuous pump operation. |