Browsing by Author "Ozsunar, Abuzer"

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Determination of Heat Transfer Coefficient Between Heated Floor and Space Using the Principles of ANSI/ASHRAE Standard 138 Test Chamber
    (2017) Evren, M. Fatih; Ozsunar, Abuzer; Biyikoglu, Atilla; Kilkis, Birol; 0000-0003-2580-3910; A-5233-2016; A-5233-2016
    In this study, heat transfer coefficients for radiant floor heating systems were investigated in a special test chamber that is one of the very first implementations of ANSI/ASHRAE Standard 138 in the world. Radiant systems offer high energy- and exergy-efficient sensible heating and cooling potential. These systems can be directly coupled with low enthalpy, renewable, or waste heat resources. Heat transfer coefficients are important design parameters for radiant systems that effect the heat transfer capacity of the heated/cooled surface to the indoors. In this study, radiant, convective, and total heat transfer coefficients for radiant floor heating were investigated experimentally. Experiments were conducted in a special test chamber that was established according to ANSI/ASHRAE Standard 138 with minor differences. The test chamber dimensions are 2.74 x 2.25 x 2.45 m (8.99 x 7.38 x 8.04 ft) and there are no floor coverings during the test. Coefficients were determined through two difference methods. Heat fluxes from the heated floor that calculated via both methods and obtained from the "Design Graph for Sensible Heating and Cooling with Floor and Ceiling" in ASHRAE Handbook-HVAC Systems and Equipment (ASHRAE 2008). According to the experimental results, total heat transfer coefficients for the radiant heating system were obtained between 8.8 and 12.1 W/m(2)K (1.43 and 2.13 Btu/h.ft(2).degrees F).
  • No Thumbnail Available
    Item
    Experimental Investigation Of Energy-Optimum Radiant-Convective Heat Transfer Split For Hybrid Heating Systems
    (2016) Evren, Mustafa Fatih; Ozsunar, Abuzer; Kilkis, Birol; https://orcid.org/0000-0003-2580-3910; AAJ-2321-2020
    In this study, indoor radiant-convective heat transfer split of hybrid heating systems has been experimentally investigated in order to quantify the advantages of hybrid heating systems for thermal comfort in terms of operative temperature for thermal comfort and energy consumption. Operative temperature is a key parameter which is a function of indoor surface temperatures, clothing, air movement and dry-bulb air temperature. Controlled experiments were carried out in a special test chamber which was constructed according to ANSI/ASHRAE Standard 138. In this test chamber all interior surface temperatures and the dry-bulb air temperature were independently controlled. Two different types of electric fan heaters, with equal heating capacities but different fan powers, were hybridized with hydronic floor heating. In the series of experiments; fan heaters and the floor heating system were operated with different heating capacities simultaneously and hereby radiant-convective split was varied where the corresponding energy consumptions were recorded. During the process of obtaining the optimum radiant-convective heat transfer split; human comfort and energy consumption parameters were analyzed in terms of the operative temperature and exergy. According to the results of the experimental data and operative temperature-based optimization, optimum interval of radiant-convective split has been found to be between 0.65 and 0.75. (C) 2016 Elsevier B.V. All rights reserved.