Looking for solutions to reduce air conditioner heat flow: Case study of an Academic Research Laboratory

Abstract

Abstract Energy consumption in the building sector has become a global concern. Among the most energy-intensive equipment: air conditioning units, especially in hot countries. This paper investigates this rise of energy consumption for a case study of a laboratory located at the National Engineering School of Tunis, Tunisia. The key idea of this paper is to look for an optimal solution to reduce the energy consumption of the air conditioner while ensuring occupant’s comfort. For this purpose, firstly a laboratory dynamic thermal model is designed. Then, a Hysteresis control is adopted to ensure thermal comfort and to maintain the ambient temperature within a range predefined by the user. To achieve an outcome compatible with expectations, the thermal transfer through laboratory wall’s envelope constituents, considering loads effects on air conditioner functioning and, meanwhile, the energy balance of the system are analyzed. Then, a comparative study of different solutions to improve the energy consumption of the laboratory was also carried out. The results indicate that the use of double-glazed windows is the most suitable. The window model used guarantees an energy gain of 27% if it is used only for the windows of the east wall and an additive gain of 30% if it is used for all the openings. Otherwise, if an external insulation is adopted, the energy gain is negligible. The proposed model is implemented in Matlab / Simscape and results are validated by the experimental measurements provided by a network of temperature sensors and transmitted to cloud service.