Serkan ERDEM - Academia.edu (original) (raw)

Papers by Serkan ERDEM

Tesisat Mühendisliği, 2020

Tesisat Mühendisliği, 2021

Journal of Energy Systems, 2021

R1234yf is a synthetic HFO refrigerant co-developed as a replacement refrigerant for R134a in aut... more R1234yf is a synthetic HFO refrigerant co-developed as a replacement refrigerant for R134a in automotive air conditioning applications. Thus, in this study, alternatives to the R134a refrigerant that were removed from the newly produced devices were examined. The performance of the cooling processes of R1234yf and R744 refrigerant gases was compared with that of R134a. A simulation model was first developed. This simulation model was validated with experimental results. Analysis was conducted for both cooling and heating modes. In the case of cooling, evaporation temperature was 5 °C-7.5 °C, condenser, or gas cooler outlet temperature was 35 °C-50 °C and the cooling load was 10 kW. In heating mode, evaporation temperature was −4 °C-12 °C, condenser, or gas cooler outlet temperature was 45 °C-50 °C and the heating load was 13.5 kW. The results were analyzed in terms of the coefficient of performance (COP), compressor power consumption, and compressor discharge temperature. In terms of COP and compressor power consumption, R134a gave the best results in all cases. R1234yf gave the closest results to R134a. In terms of compressor discharge temperature, which affects the lifetime and lubrication quality of the compressor, R1234yf gave the lowest temperatures in all cases.

International Journal of Air-Conditioning and Refrigeration, 2021

In zones separated by doors with many entrances and exits, it is crucial in terms of energy consu... more In zones separated by doors with many entrances and exits, it is crucial in terms of energy consumption to protect the conditioned air in the indoor environment from the effects of outside air. The increase in door dimensions and opening frequency make this effect even more evident. Various methods are used to prevent leakage of outside air into the indoor environment. In this study, we investigated the effects of using air curtains on energy consumption during the cooling season in a factory building. The door width and height in this building, which has a high story height, were also large. These 26 doors must remain open all the time because of the production process. With a transient model developed on Transient System Simulation Tool (TRNSYS) coupled with Contaminant Transport Analysis Software (CONTAM), we showed the effects of using the air curtains in different climate conditions. As a result, we demonstrated that using air curtains will provide great savings, especially in ...

Heating and cooling of offices, residential sites, hospitals, courthouses and etc. is more effici... more Heating and cooling of offices, residential sites, hospitals, courthouses and etc. is more efficient with central heating and cooling. The use of renewable energy sources is important in these applications today. Therefore, to meet heating and cooling needs of a sample site consists of several housing, calculation is made of consisting of three different renewable energy systems. First, solar-assisted ground source heat pump (SA-GSHP) system is designed. Second, solar assisted cooling systems are examined and solar assisted absorption cooling system (SA-AC) is designed. Finally, investment and operating costs are calculated of the same site, when the heating is done with a boiler and the cooling is done with an air cooled chiller. Thus, the investment and the operating costs have been compared of these three different heating and cooling applications.

International Journal of Mechanical Engineering and Robotics Research, 2017

Trigeneration electric production can be defined as a power system in which heating and cooling a... more Trigeneration electric production can be defined as a power system in which heating and cooling are simultaneously produced. In this study, we attempted to decrease the energy consumption of a pharmaceutical factory. For this purpose, a trigeneration application was carried out based on the data from a currently active pharmaceutical factory in Istanbul, Turkey. The costs of exergy and exergy losses, the ratios of exergy losses, and the exergy economic factor parameters of the equipment were determined. The exergy economic factors were found and in view of these parameters, assessments were made to determine the improvements that could be made in the system equipments. 

Thermal Science, 2018

In this study, the optimum insulation thickness was calculated for the heating season for externa... more In this study, the optimum insulation thickness was calculated for the heating season for external walls in the different directions of a building. For this reason, a building used for housing in Istanbul, Turkey was taken as model. The indoor and outdoor temperatures, along with the interior and exterior surface temperatures of the building?s external walls, were continuously measured using thermocouples and recorded in four different directions throughout the year. The effects of solar radiation, which vary based on the direction, were assessed for the heat transfer through the external walls. The results of this study indicate that the optimum insulation thickness for the north, south, west, and east facing walls should be 6.47, 2.87, 6.97, and 6.98 cm, respectively, based on the differences in the amount of solar radiation exposure of the walls in the different directions. The optimum insulation thickness of the building?s external wall was calculated as 5.25 cm, regardless of i...

Drying Technology, 2014

CO2 appears to be a suitable refrigerant for dryer operation conditions due to its thermophysical... more CO2 appears to be a suitable refrigerant for dryer operation conditions due to its thermophysical and environmentally friendly properties. In this study, a heat pump tumble dryer system using CO2 as the refrigerant was theoretically investigated, and a computer model was developed using MATLAB software. The changes in the energy consumption and drying time, depending on the inlet CO2 pressure into the gas cooler, inlet CO2 temperature into the evaporator, air mass flow rate, and dryer efficiency, are presented. The results show that the optimum operating parameters are extremely effective in reducing the drying time and energy consumed.

International Journal of Refrigeration, 2015

A heat pump tumble dryer model was developed to investigate the effects of evaporator geometry on... more A heat pump tumble dryer model was developed to investigate the effects of evaporator geometry on drying time and energy consumption. The model was validated using experimental data available in the literature. The effects of the evaporator's geometrical specifications on heat and mass transfer and pressure drops on both sides of the evaporator were investigated. Then, the energy consumption and drying time of the dryer were determined. The results indicated that the energy consumption is reduced by 12% when the number of rows in the evaporator is increased from 2 to 4. Increasing the number of columns from 2 to 4 could reduce energy consumption by 8%. The energy consumption increases by 18% when the outer diameter of the tube is increased from 6 mm to 10 mm. Increasing the longitudinal tube pitch from 10 mm to 30 mm leads to a 21% increase in energy consumption.

Heat pumps working with CO 2 as a refrigerant have low energy consumptions depending on selected ... more Heat pumps working with CO 2 as a refrigerant have low energy consumptions depending on selected application areas and operating conditions. The use of CO 2 in heat pump dryers is feasible if operating temperatures are appropriate. In heat pump dryers working with CO 2 according to the transcritical cycle, one of the most important operating conditions is optimum gas cooler inlet pressure, which gives the maximum coefficient of performance (COP). In this study, a model was developed by using MATLAB software for heat pump tumble dryer working with CO 2. The model was validated by experimental data taken from existing literature. Then, COP, moisture extraction rate (MER), and specific moisture extraction rate (SMER) were found by running the model at different gas cooler inlet pressures (80-140 bar). All results were calculated in the same geometry for evaporator, gas cooler, and compressor. Thus, effects on the results of variation of the geometrical features were eliminated. Optimum gas cooler inlet pressure was determined with data input to the model as 100 bar for the system. In the optimum gas cooler inlet pressure working condition, SMER increased 24% and 12% by comparison with 80 bar and 140 bar gas cooler inlet pressure, respectively.

In heat pump tumble dryers, moisture separates from the laundry and leaves the dryer system at th... more In heat pump tumble dryers, moisture separates from the laundry and leaves the dryer system at the evaporator. Moist air goes out the drum and enters the evaporator whose outer surface is below the dew point temperature. Air cools and then leaves its moisture. At the airside of the evaporator the wet surface develops and simultaneous heatmass transfer occurs. Fin-and-tube heat exchangers are used as evaporators in household heat pump tumble dryers. In addition to optimum operating conditions, optimum evaporator geometry can significantly affect system performance. In this study, a model was developed for household heat pump tumble dryer. The model was validated by experimental data collected from the literature. MATLAB software was used in programming, and fluid properties were taken from Refprop software. The model was run with different fin spacing (2-5 mm) and tube outer diameter (6-12 mm) for evaporator, whereas operating conditions and all other geometrical parameters stayed the same. Then, coefficient of performance (COP), moisture extraction rate (MER), and specific moisture extraction rate (SMER) were calculated. As a result, the effects of fin spacing and tube outer diameter of evaporator were determined depending on the input characteristics of the dryer model. In the working range, SMER was changed up to 20% and 15% depending on the fin spacing and the tube outer diameter of evaporator, respectively.

Advances in Mechanical Engineering, 2014

Simultaneous heat and mass transfer are investigated in a falling film outside grooved and smooth... more Simultaneous heat and mass transfer are investigated in a falling film outside grooved and smooth tubes. A numerical analysis of the helically trapezoidal-grooved and reference smooth tube was performed in the computational fluid dynamics program “Ansys Fluent 14.” The three-dimensional model drawings in the x, y, and z coordinates are used, and the effects of the falling film outside the helically grooved tube on the surface temperature and surface heat transfer coefficient are determined. The average surface temperature, heat transfer coefficient, and Nu values are determined experimentally for a constant heat flux. An uncertainty analysis and Nu correlation for the grooved tube are also provided in this study. The Reynolds number varied between 50 and 350 for the falling film and between 1500 and 3500 for air. Using a computational fluid dynamics (CFD) analysis for the reference smooth tube, the experimental results are validated within 2–12% difference. The experimental results ...

Volume 7: Fluids and Heat Transfer, Parts A, B, C, and D, 2012

The current building inventory in Turkey includes a large number of uninsulated buildings. By ins... more The current building inventory in Turkey includes a large number of uninsulated buildings. By insulating these buildings, the required heating energy is decreased, and significant energy savings are achieved. Within the country, the standard “Thermal Insulation Requirements for Buildings” was placed into effect in buildings in the year 2000 and divided the country into four climatic regions. The optimum insulation thickness in buildings changes as a function of the region, type of insulation material and fuel. In this study, the implemented insulation thickness according to the “Thermal Insulation Requirements for Buildings” standard is calculated for the four different regions of Turkey for expanded polystyrene insulation material. The current building inventory in Turkey was taken from the State Institute of Statistics (Prime Ministry, Republic of Turkey). Energy savings, costs and payback period are calculated by the P1-P2 method for the current building inventory, using XPS insulation in all buildings and natural gas as the fuel for the heating energy requirements. The results are shown in the figures for the four different climatic regions, and the effect of the current building inventory distribution around the country is determined.© 2012 ASME

Energy, 2010

A solar assisted absorption refrigeration system (SAARS) was designed for acclimatizing of villas... more A solar assisted absorption refrigeration system (SAARS) was designed for acclimatizing of villas in Mardin which is located in Turkey and the performance of the system under different temperatures was analyzed by using MATLAB. Hourly cooling load calculation of the villas was done between 15th of May and 15th of September by considering the season for the cooling. Cooling capacity of the system (SAARS) was calculated as 106 kW. During the cooling period, the temperature of the environment shows the alteration between 40.3 C and 13.2 C. In the study, hourly exergy loss values are calculated with the software developed in matlab program and for the entire components of SAARS. The effect of the temperature alterations of the dead state on the exergy results is determined by taking dead state temperature as 25 C and with more realistic approach, by taking it as the environment temperature. It was observed that the most of the exergy losses in the system have taken place in the solar collectors and then in the generator. Exergy loss in the collector changes between 10% and 70% while exergy loss in the generator changes between 5% and 8%. The effects of environmental temperature and solar insolation were stated for optimization.