Paper Conference

Proceedings of eSim 2002: 2nd Conference of IBPSA-Canada

     

CONTROL STRATEGIES OF OPEN CYCLE DESICCANT COOLING SYSTEMS MINIMISING ENERGY CONSUMPTION

Stéphane Ginestet, Pascal Stabat, Dominique Marchio

Abstract: Open-cycle desiccant cooling systems generally operate either in indirect evaporative cooling or in desiccant cooling mode depending on outdoor air conditions. In addition to the switch point temperature between evaporative and desiccant cooling, the regeneration temperature and the supply airflow rate are key control parameters to achieve optimal cooling performance. The influence of these control strategy parameters on the efficiency of desiccant cooling has been investigated. The study of the performance of the desiccant cooling system versus the regeneration temperature and the air flow rate underlines that specific control strategies must be defined depending on reactivation energy: free energy (waste heat, solar energy) or no free energy (natural gas, district heat, electricity). The components of the desiccant cooling system have been modelled including desiccant wheel, rotary heat exchanger and humidifiers with the aim to account for variable regeneration temperature and supply air flow rate. Both the system model and a building simulation software have been implemented in Matlab-Simulink environment. The control strategy has been integrated by using a finite state machine representation. This paper gives optimised control strategies for both energy source types in office building applications for a reference hot day. The results show how these HVAC systems are able to meet the cooling demand for different cases of building loads and thermal inertia and in different climates.
Paper:
esim2002_1-1