Determination of economic optimum insulation thickness of indoor pipelines for different insulation materials in split air conditioning systems

Abstract

This paper presents investigation of optimum insulation thickness, energy savings and payback periods for gas pipeline and liquid pipeline under the heating and cooling modes of a split air conditioning system using R-407C as refrigerant. Analyses are performed for four different insulation materials indicated as extruded polystyrene, foamboard, rockwool and expanded polystyrene. In consequence of the calculations, the optimum insulation thickness of gas pipeline vary from 45 to 50 mm, the energy saving vary between 78 and 83%; and the payback period vary from 0.025 to 0.468 years, whereas, the optimum insulation thickness of liquid pipeline vary from 28 to 45 mm, the energy saving vary between 40 and 79%; and the payback period vary from 0.044 to 0.289 years. Finally, for both gas and liquid pipeline, the expanded polystyrene is a better choice when the optimum insulation thickness is an important consideration.