The effect of wind speed on the economical optimum insulation thickness for HVAC duct applications Abdullah Yildiz a,n , Mustafa Ali Ersöz b a Department of Mechanical Engineering, Faculty of Engineering, Uşak University, 64200 Usak, Turkey b Department of Electricity and Energy, Vocational College of Uşak, Uşak University, 64200 Usak, Turkey article info Keywords: Optimum insulation thickness Energy savings Life-cycle analysis HVAC abstract This study deals with the investigation into optimum insulation thickness of HVAC ducts and the effect of wind speed on it for the city of Uşak, Turkey. Optimum insulation thickness, energy savings over a lifetime of 10 years and payback periods are determined for the four different energy types as coal, fuel– oil, LPG and natural gas and two different insulation materials as fiberglass and rockwool. By using the P 1 –P 2 method, the value of the amount of the net energy savings is calculated. The results indicate that optimum insulation thicknesses vary between 12.85 and 23.91 cm, energy savings 79.36 and 98.45%, and payback periods 0.0053 and 0.0925 years depending on the type of fuel for fiberglass, whereas, optimum insulation thicknesses vary between 11.87 and 22.21cm, energy savings 76.63 and 98.26%, and payback periods 0.0061 and 0.1115 years depending on the type of fuel for rockwool. Moreover, 7ms À1 wind speed for LPG is highest in energy saving but 0.2 ms À1 wind speed for natural gas is lowest in energy saving. Finally, the application of insulation in high wind speeds is more advantageous. & 2015 Elsevier Ltd. All rights reserved. Contents 1. Introduction .......................................................................................................... 1 2. Description of system .................................................................................................. 4 3. Analysis ............................................................................................................. 4 3.1. Heat loss through HVAC system duct network ........................................................................ 4 3.2. Life cycle analysis and optimization of insulation thickness .............................................................. 8 4. Results and discussion................................................................................................. 10 5. Conclusions ......................................................................................................... 11 References .............................................................................................................. 12 1. Introduction HVAC stands for “heating, ventilation and air conditioning,” three functions often combined into one system in today's modern homes and buildings. Among building energy services, HVAC systems are the most energy consuming devices, accounting for about 10–20% of final energy use in developed countries [1]. Only heating systems, prevalent in cold climates, have such source of heat generation as natural gas, fuel oil, liquid petrol gas or coal and typically use air to deliver the heat to the conditioned space and the hot air flows through a series of tubes – called ducts – to be distributed to all the rooms of building's occupants. Typical duct locations of HVAC system are outdoor environment, attics, crawlspaces and garages. Putting ducts in these non-conditioned areas increases the potential for energy losses from the duct system because the duct are exposed to a harsher environment and energy loss from the ducts is outside the conditioned envelope of building. These losses contribute to large energy bills for home owner and to large peak demands for utilities. Therefore, thermal insulation of the HVAC ducts is one of the most valuable tools to prevent these heat losses and also the thermal insulation prevents condensation on the duct surface. Determining both the type of thermal insulation material and the economic thickness of the material used in the HVAC's duct are the main subjects of many engineering investigations. The concept of Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/rser Renewable and Sustainable Energy Reviews http://dx.doi.org/10.1016/j.rser.2015.03.073 1364-0321/& 2015 Elsevier Ltd. All rights reserved. n Corresponding author. Tel.: þ90 276 2212136; fax; þ90 276 2212137. E-mail address: abdullah.yildiz@usak.edu.tr (A. Yildiz). Please cite this article as: Yildiz A, Ersöz MA. The effect of wind speed on the economical optimum insulation thickness for HVAC duct applications. Renewable and Sustainable Energy Reviews (2015), http://dx.doi.org/10.1016/j.rser.2015.03.073i Renewable and Sustainable Energy Reviews ∎ (∎∎∎∎) ∎∎∎–∎∎∎