Ertan Alptekin

Biodiesel production from vegetable oil and waste animal fats in a pilot plant

In this study, corn oil as vegetable oil, chicken fat and fleshing oil as animal fats were used to produce methyl ester in a biodiesel pilot plant. The FFA level of the corn oil was below 1% while those of animal fats were too high to produce biodiesel via base catalyst. Therefore, it was needed to perform pretreatment reaction for the animal fats. For this aim, sulfuric acid was used as catalyst and methanol was used as alcohol in the pretreatment reactions. After reducing the FFA level of the animal fats to less than 1%, the transesterification reaction was completed with alkaline catalyst. Due to low FFA content of corn oil, it was directly subjected to transesterification. Potassium hydroxide was used as catalyst and methanol was used as alcohol for transesterification reactions. The fuel properties of methyl esters produced in the biodiesel pilot plant were characterized and compared to EN 14214 and ASTM D6751 biodiesel standards. According to the results, ester yield values of animal fat methyl esters were slightly lower than that of the corn oil methyl ester (COME). The production cost of COME was higher than those of animal fat methyl esters due to being high cost biodiesel feedstock. The fuel properties of produced methyl esters were close to each other. Especially, the sulfur content and cold flow properties of the COME were lower than those of animal fat methyl esters. The measured fuel properties of all produced methyl esters met ASTM D6751 (S500) biodiesel fuel standards.

Experimental Performance Analysis of an Automotive Air Conditioning and Heat Pump System using R134a with and without Internal Heat Exchanger

In this study an experimental system was set up from the original components of an automotive air conditioning (AAC) system. After than internal heat exchanger (IHX) and reversing valve were installed to use as heat pump and improve performance of it. For each mode of operations, the system was tested at five different compressor speeds between 800 and 2800 rpm with intervals of 400 rpm. In the heat pump mode operations without IHX, the temperatures of the air streams entering the evaporator and condenser were maintained at Tevap,ai=0°C – Tcond,ai=0°C, Tevap,ai=10°C –Tcond,ai=10°C and Tevap,ai=15°C – Tcond,ai=15°C. IHX was started up the temperatures of the air streams at the inlets of the evaporator and condenser were maintained at Tevap,ai=5°C – Tcond,ai=5°C, Tevap,ai=10°C – Tcond,ai=10°C and Tevap,ai=15°C – Tcond,ai=15°C. Using experimental data, performance parameters such as conditioned air stream temperature, compressor power, compressor mechanical power and compressor discharge temperature were evaluated. In heat pump mode provided enough heating capacity and conditioned air stream temperatures even at low compressor speeds. Furthermore, the heating capacity increased but COPh decreased with rising compressor speed however compressor power decreased and COPc increased with using IHX. Keywords—HFC134a, automotive air conditioning, internal heat exchanger. Erkutay TASDEMIRCI Kocaeli University Turkey Murat HOSOZ Kocaeli University Turkey

Energy and Exergy Analysis of an R134A Automotive Heat Pump System for Various Heat Sources in Comparison with Baseline Heating System

Performance of an automotive heat pump (AHP) system using R134a and driven by a diesel engine has been evaluated in this study. For this purpose, an experimental AHP system capable of providing a conditioned air stream by utilizing the heat absorbed from the ambient air, engine coolant and exhaust gas was developed. The experimental system was equipped with instruments for measuring engine torque and speed, refrigerant and coolant mass flow rates, refrigerant and air temperatures as well as refrigerant pressures. The system was tested by varying the engine speed, engine load and air temperatures at the inlets of the indoor and outdoor coils. Using experimental data, an energy analysis of the system was performed, and its performance parameters for each heat source were evaluated for transient and steady-state operations. Then, the performance of the AHP system for each source was compared with that of the system using other heat sources and with that of the baseline heating system. The investigated performance parameters include air temperature at the outlet of the indoor coil, heating capacity, coefficient of performance and exergy destruction rates in the components of the AHP system. The total exergy destruction rate in the AHP with engine coolant is higher than those in the AHP with ambient air and with exhaust gas mainly because of the greater refrigerant mass flow rate and heating capacity.