This study aims to investigate the mechanical properties of concrete containing phase change materials (PCM). This research begins with the investigation of melting temperature, enthalpy, the thermal conductivity of the phase change materials using the T-history method, followed by preparation of concrete containing PCM, and finally testing of mechanical properties of concrete through compressive strength test. This study used beeswax, tallow, and dammar gum as PCM mixture. From the results of the PCM properties test, shows that the latent heat energy content from beeswax and tallow exhibit an excellent potential to be used as PCM, while dammar gum is benefited in increasing the thermal conductivity of concrete containing PCM. From concrete specimen test containing 10%, 20% and 30% PCM with 7 days and 28 days aged, the results exhibit that the mechanical properties of the concrete decreased along with the increasing of PCM content. The same test also conducted at the PCM melting temperature. Therefore, the concrete compressive strength test conducted at 45 oC. From the test results, the concrete compressive strength decreased about 3–24% of PCM-0% concrete compressive strength. Drastic compressive strength reduction tends to occur in PCM-Tallow concrete mixture. This study concluded that the PCM is potentially useful as a heat energy absorber material in buildings and lightweight concrete rather than construction structures.

The reduced production of fossil energy, especially petroleum, has encouraged researchers to continuously increase the role of new and renewable energy as part of energy security and independence. A Tesla turbine is a device that can be used to recover wasted energy from exhaust gases, thereby increasing the overall energy use. The purpose of this study was to assess the performance of a Tesla turbine using various parameters such as engine speed, the gap between the disks, the diameter of the disks, and the number of disks. In this study, the performance of a Tesla turbine was simulated using computational fluid dynamics (CFD). The reference dimensions of this Tesla turbine are made with a slit diameter of 44 mm, a hole diameter of 10 mm, disc diameter of 140 mm, a disc width of 1.5 mm, a disc gap of 35 mm, a disc gap width of 4 mm, and a shaft length of 50 mm. The results of this study were in the form of torque and pressure drop values. In the variation of engine speed, the highest torque was at 1800 rpm with a torque value of 0.422 Nm, and the highest pressure drop was at 1800 rpm with a pressure drop value of 79161.5 Pa. In the disk gap variation, the highest torque is at a 7 mm disk gap with a torque value of 0.54 Nm and the highest pressure drop is at a 4 mm disk gap with a pressure drop value of 79161.5 Pa. In the variation of disk diameter, the highest torque was found on the disk with a diameter of 180 mm and a torque value of 0.831 Nm, and the highest pressure drop was on a disk with a diameter of 180 mm and a pressure drop value of 86753.5 Pa. In the variation of the number of disks, the highest torque was found at eight disks with a torque value of 0.765 Nm, and the highest pressure drop was found at eight disks with a pressure drop value of 82031.3 Pa. After performing this simulation, it can be concluded that at variations in engine speed, the higher the engine speed, the higher the value obtained and the variations in the disk gap, disk diameter, and number of disks. There are several values of torque that increase and decrease because the input value given cannot always increase the torque value in these variations.

One way to overcome the scarcity of clean water through sustainable approach is by utilizing a solar distillation system. This easy-to-use technology is adopting tubular solar distillation. The three main components, which are the most essential for producing the amount of permeate, are the solar collector, tubular and heat exchanger (HE). This study aims to determine the performance of a tubular solar distillation device equipped with HE using a parabolic trough collector (PTC). The PTC has an area of 5.1 m² covered with a solar reflective chrome film. Aluminum tubular acts as the feedwater heater. The HE is placed inside the tubular, which acts as a coolant to convert the steam phase into freshwater/permeate and as a feedwater heater to flow into the tubular. In the present study, several parameters were tested: comprise temperature, solar radiation, pressure, humidity, mass flow rate, permeate productivity and efficiency. This study demonstrated the production of a sufficient amount of permeate, which was 5.32 L for 6 h. The efficiency of this device yielded a peak of 48.2% during solar radiation of 813 W/m² in an average ambient temperature of 32 °C, with an overall average of 44.59%.

Despite the rapid development of electric vehicles, the shrinking number of fossil fuels that are the source of electricity remains conventional. The availability of energy sources and technology is sometimes naturally limited, high-priced, and might be politically circumscribed. This leads to an increased desirability of biodiesel due to its modest and economically higher energy density in comparison to batteries. The palm oil industry accounts for 23% of total deforestation in Indonesia. Contrary to palm oil, pangium edule (PE) is considered more sustainable and it intercrops with most of the forest’s vegetation while supplying biodiesel feedstock. A relatively higher pangium edule methyl ester (PEME) was delivered through PE feedstock, provided that it was processed with a heterogeneous catalyst, K2O/PKS-AC. This feedstock consumed a lower alcohol ratio and had a reasonably swift production process without sacrificing biodiesel quality. Therefore, this study aims to assess the performance of the PE biodiesel blend in a power generator. Furthermore, PEME was blended with diesel fuel in the variation of B0, B20, B30, B40, and B100. It was also tested with four-stroke single-cylinder diesel power generators to produce electricity. The B30 blend stands out in this experiment, achieving the highest engine power of 0.845 kW at a low load and dominating at a higher load with a minimum fuel consumption of 1.33 kg/h, the lowest BSFC of 0.243 kg/kWh, and second in BTE values at 21.16%. The result revealed that the main parameters, which include actual and specific fuel consumption, and the thermal efficiency of PE biodiesel performed satisfactorily. Although there was a slight decrease in the total power delivered, the overall performance was comparable to petroleum diesel.

The air conditioning system is the most common way to provide comfortable room temperature for its inhabitants. However, the energy required for its operation is extremely high and cost-intensive. Therefore, a more efficient HVAC system with a lower energy consumption is desirable. The experimental results and performance analysis demonstrated that the outlet air temperature through the evaporator side of HPHE (precooling) has the potential to save some amount of energy utilizing an HVAC system equipped with HPHE. This research aims to study the performance of HPHE with the precooling process applied in commercial room HVAC system applications. This research on the utilization of HPHE for heat recovery in air conditioning systems was carried out with variations in temperature of fresh air intake ranging between 32–42 ℃. The airflow speed was set constant at 1.0 m/s. This experiment demonstrated the highest effectiveness at a value of 21%. The HPHE heat recovery analysis results show that the best heat recovery performance is achieved when the fresh air intake temperature exceeds the exhaust air leaving the room. The phenomenon was compared at a low fresh air intake temperature of 32 ℃, which succeeded in recovering 0.05 W, and when the temperature rose to 42 ℃, 0.21 W was recovered.

Thermal energy storage using Phase Change Materials (PCM) is now widely applied to wall buildings. In general, PCM which is used for applications on building walls is organic PCM and has temperature range from 0℃ to 65oC. Beef tallow and coconut oil is a type of organic PCM known as Bio PCM needs to characterize by using the T-History Method. The T-History method is more accurate than Differential Scanning Calorimetry (DSC) and Differential Thermal Analysis (DTA). This study aimed to determine the thermal properties of beef tallow/coconut oil PCM using the T-History method. The beef tallow and coconut oil as bio PCM material was used in this study with the variation are respectively: 100%, 70+30%, 60+40%, and 50+50%. Tests are carried out using the T-History method. From the results of testing and analysis obtained supercooling temperature, melting temperature, specific heat, and latent heat for bio PCM beef tallow/coconut oil. The effect of adding coconut oil mixture to beef tallow caused a decrease in melting temperature and supercooling temperature, while the specific heat and latent heat of bio PCM of beef tallow/coconut oil ranged from 2.96-2.19 kJ/kg.℃ and 101.05-72.32 kJ/kg. The result obtained that this bio PCM material of cow beef tallow/coconut oil can apply, as additional material in wall building applications.