Optimal economic thickness of pipe insulation considering different pipe materials for HVAC pipe applications

This study aims to optimize the thickness of the insulation layer in the pipes made of different materials for HVAC pipe applications. The pipes used are made of steel, plastic and copper. In case of using some fuel types and various insulation materials based on climatic conditions of Afyonkarahisar, Turkey as a case study, the annual total cost, energy saving and payback period associated with insulation applications to the pipes of different diameters are evaluated. For the optimization process, the life cycle cost analysis based on heating degree-days is used. The results primarily showed that the most saving fuel and insulation material are respectively fuel oil and rockwool. The insulation priority for pipe materials is in the order; copper, steel and plastic. As the plastic pipes have a low heat conduction coefficient, this is not the most appropriate method to determine the optimum insulation thickness. When taking into account all variable parameters in the analysis, the optimum insulation thicknesses for steel and copper pipes varied from 5 to 16 cm and 5-12 cm, respectively. In conclusion, a fixed insulation thickness can be used in large diameter steel and copper pipes.