Biodiesel, which is most commonly derived from vegetable oils, and waste cooking oil, is an alternative to petroleumbased fuels. Since vegetable oils are also an important commodity in the food market, their prices are expected to increase substantilly given their broadening usage. Hence, waste animal fats are being considered as a promising cheap alternative feedstock for biodiesel production. Animal oil is extracted mainly from rendered tissue fats derived from livestock animals like pigs, chickens and cows. The objective of this study is to study the effects of extraction method of animal fatty tissues. Our extraction method is composed of high temperature extraction (100～140℃, 0.10 Mpa) is first applied to 40 kg of fat tissue for 2～3 h. Following this, the second step (70～ 100℃, -0.09 MPa), is applied for 60 min. This method resulted in a recovery of 69.4% of the total fat oil of the tissue. Major fatty acids from the extracted animal oils were palmitic, stearic, and oleic acid. Average contents and ranges of saturated fatty acids (SFA) palmitic acid and stearic acid, were 25.8% (23.5～28.9%), and 11.4% (7.8～14.4%), while those of unsaturated fatty acids (USFA) oleic acid and linoleic acid were 46.4% (41.6～51.7%) and 3.1% (1.4～8.1%), respectively.

This study was conducted to investigate the effects of a number of factors (moisture content and particle size of sawdust and operating time of flat-die pelletizer) on the fuel characteristics of wood pellets fabricated from Mongolian oak (MOK) and pitch pine (PCP) sawdust. MOK and PCP pellets were produced from sawdust of varying moisture content (8, 10, 12%) and was screened to mesh sizes of 2 and 4 (0.64 and 1.27 mm). Moisture content (MC), bulk density (BD) and durability (DU) of the produced pellets were also determined based on the operating time of the flat-die pelletizer (10, 20, 30, 40, 50 And 60 min). The MC of both MOK and PCP pelletswere not altered based on their duration in the flat-die pelletizer. However, the BD and DU of MOK pellets were higher than those of PCP pellets. Increasing the MC of the sawdust resulted in an increase in pellet MC and BD, reducing their fuel value. The BD of PCP pellets was greatly decreased when sawdust with a MC of 12% was applied. The DU of both MOK and PCP pellets increased when the MC was increased from 8% to 10%. However, no further increase in DU occurred through the use of MOK sawdust with a MC of 12%, and the DU of PCP pellets was reduced through the use of a MC of 12%. Pellet MC, BD and DU were not influenced by the particle size of sawdust, or by the operating time of flat-die pelletizer. On the other hand, BD and DU of MOK and PCP pellets were lower than those of Larch pellets which, having very suitable characteristics, were used as a reference pellet in this study. In conclusion, MOK pellets with suitable fuel characteristics, satisfying the minimum requirement of the 1st-grade pellet standard designated by the Korea Forest Research Institute, were produced. However, the BD and DU of PCP pellets were lower than the standard, and especially, the DU of PCP pellets produced with the sawdust MC of 12% was inferior to the standard for 4th-grade pellets (?95.0%). Based on the results, 10% MC for MOK sawdust might beoptimal for the production of MOK pellets, but PCP alone is not suitable as a raw material for the production of wood pellets under the experimental conditions examined in this study.

There is an ever-growing interest in alternative energy sources, and more and more technologies are becoming viable options as efforts to reduce greenhouse gas production and fossil fuel consumption increase. Unutilized energy has been attracting particular attention as a community based alternative energy source. Temperature difference energy is ubiquitous in nature, and it may be possible to harvest this energy without any significant influence on the local environment.In this study, we examined reserves and available capacity of temperature difference energy sources(treated sewage, river water, and an agricultural reservoir) for the supply of energy to a rural community.Reserves and available capacity of treated sewage were 6,555 Tcal/yr and, 4,318 Tcal/yr, respectively, while reserves and available capacity of river water were 192,000 Tcal/yr and 1,632 Tcal/yr, respectively. Agricultural reservoirs returned reserve and available capacity figures of 7,994 Tcal/yr and 141 Tcal/yr, respectively. In addition, we presented a review of legal and systematic considerations which might pave the way for larger scale temperature difference projects in the future. We also suggest a direction for future temperature difference energy based on the current Korean legal system.

This study is evaluates the performance of a prototype ground source heat pump(GSHP) system under various secondary fluid flow rates. The prototype GSHP has four functions : space heating, cooling, floor heating and domestic water heating. Heating can be operated by two operational modes : water to water and water to air. As a result, the COP of GSHP was increased from 3.43 to 3.84 when the underground circulation flow rate was increased, but ratio of increased in COP was decreased. When the flow rate of the GSHP system including electricity consumption of the ground circulation pump was increased 19.2 LPM to 47.4 LPM, the COP was increased by up to 6.1%, but flow rate was increased 47.4 to 87.7 LPM, the COP was decreased by up to 6.2%. It is suggested that the GSHP with an underground circulation inverter pump saves power consumption in the operation mode, a variable-speed control of ground circulation flow rate based on a compressor Hz have to be selected in order to optimize COP of GSHP system.

Electroactive polymers (EAPs) generate electric energy when subjected to various mechanical stimuli. Among EAPs, Ionic Polymer-Metal Composite (IPMC) has been applied to a wide variety of environmental conditions for the purpose of energy harvesting. IPMC consists of an ion conductive membrane plated with metallic electrodes on both surfaces. Since IPMC is soft and hydrophilic, it has the potential to be applied to ocean wave energy harvesting. However the fabrication cost of IPMC is relatively high, as platinum is usually used as the electrode material and the electrode plating procedure is complex, resulting in the difficulties of large scale implementation in energy harvesting applications. In this paper, a cost effective fabrication method for energy harvesting film, using the ion conductive film, Nafion® and Carbon Nano Tube (CNT)-graphene based conductive paste as the electrode material, is presented. The energy generation characteristics of the fabricated Ionic Polymer-Conductive Layer Composite (IPCLC) was tested and compared with the performance of Pt electrode based IPMC using a wave simulator. The results reveal that the energy generated using IPCLC is about 60% that generated using IPMC.

It will be desirable things that if cooling and heating can be obtained simultaneously with one device without using power. This study was tried to investigate the feasibility for combined device of unpowered cooling and heating. The absorption device of solar heat was contrived to perform natural cooling in case of summer and natural heating in case of winter, respectively. For these purposes, experimental structure (house) and absorption device of solar heat, which was performed surface treatment, were manufactured and tested over summer and winter. As the results, in summer, inlet flow rates of air in case of installing absorption device of solar heat were increased about 12 to 20 times compared with those of no installing. In winter, the case of installing absorption device of solar heat showed maximun 6℃ high temperature in day time and 1～3℃ high temperature in night time compared with those of no installing. Furthermore, inside temperature of experimental structure showed maximun 14℃ higher than outside temperature in day time.