Research And Accomplishment Of Gshp Air Conditioning System’s Automatic Control Strategy

Energy saving of air conditioning system is a urgent problem. In recent years, GSHP system use surface layer heat as its heat source to supply heat and cold and is widely adopted for its distinguished environmental protection and energy saving feature. However, during the actual operation, its complicated system composition, manual operation error and lacking of work experience will cause improper operation management and huge resource waste. Meanwhile, heat unbalance problem has been the main restriction of GSHP system’s ordinary operation and use. In order to solve the current problem in GSHP control system, this paper invented a reasonable and reliable system control strategy and corresponding control software.Firstly, this paper contrasted and studied the GSHP air conditoning chilled water control system and obtain a reasonable primary pump control strategy. Experiment and theoriotical analysis was foucused on GSHP’s main part underground pipe system and research the main factor which affact the system operation efficiency. The research told us that lower the supply water temperature of the undergound pipe would bring higher system efficiency. The medium velocity in the underground pipe has a reasonable range which is0.4m/s-0.6m/s in Shanghai. The research also proposed a resonable and effective invertor control of underground pipe partition operation. This paper also studied the auxiliary control strategy of GSHP combined cooling tower system in Shanghai and obtained combination operation mode among electric3-way valve control by supply water temperature control and control by season.Secondly, our team establised a GSHP experimental platform on the basis of above and designed a set of feasible automatic control strategy according to the platform. The net control strategy has three levels which is sensor and actuator field as element level, PLC contronler and single circuit controler as control level and LAB VIEW software as manage level. The control straregy can make whole design and debug of the whole control system hardware and data exchange among different levels.Furthermore, this paper invented a convenient and high visual GSHP automatic control software according to the control strategy and experimental platform. This software can real-time monitor the soil temperature field and system operation conditon, can set and adjust the system operation parameter, can provide alert when air conditioning system temperature overrun and system error happen and can real-time display, store and print of the system data.Finally, this paper made cite adjustment and analyse of the whole system’s software and hardware and obtain the conlusion is that, this system is of stable operation and energe saving feature and can eliminate the heat unbalance phenomenon of the underground pipe to some extent.The control strategy and automatic control software studied in this paper will have signaficance in improving GSHP system. Its visual feature can let operator clearly see the operation conditon and can largely decrease the operation management fee. It can also solve the soil heat accumulation problem of GSHP which be benefit to the further development of actual GSHP air conditioning construction.