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%.

Indonesia has been blessed with excellent solar heat distribution, which can be used as renewable energy to heat water. Various technologies have been developed to utilize these inexhaustible thermodynamic resources, in the form of photons arrays, converted into concentrated heat for daily use, i.e., solar water heater. This renewable-based water heating system can provide significant energy efficiency, benefit the environment, and reduce energy use costs. This experimental study attempts to harvest the energy from the sun using a cylindrical through collector (CTC) type solar concentrator. The CTC was made of the solar reflective film (SRF) affixed to concentrator collector surfaces which was then mounted on an adjustable angle frame of the concentrator collector support. The heat generated from the concentrator was stored in water, and phase change material is embedded in the system to retain the heat longer. The research was carried out in Langsa City, Aceh, Indonesia. The results showed that water heaters using CTC systems could produce 16 L of hot water retained at 40–60 °C for four hours. With the addition of beeswax, the water temperature of the same capacity can be maintained at 40–60 °C for around 5 h. This technology demonstrated an excellent result that produces as much as 60 L of water per day, increasing solar thermal energy efficiency. This technology presented a great potential for replication or even for further development on an industrial scale.

The advantages of latent heat storage systems are heat storage materials capable of providing large energy storage densities and are capable of storing heat at almost constant temperature according to the transition temperature at each phase change. The thermophysical properties of phase change material (PCM) materials are important to know before they are applied in a variety of uses. The thermophysical properties of PCM materials are very important to note i.e. melting point, super cooling temperature, latent heat, heat type and thermal conductivity of the PCM material. Methods of determining the thermophysical properties of PCM materials that have been widely used are differential thermal analysis (DTA), differential scanning calorimetry (DSC), and calorimetry. These three methods have weaknesses. DTA and DSC methods that have very small test samples (110 mg) cause the materials thermophysical properties to be different when used in larger quantities. Another disadvantage is that DTA and DSC measurement equipment is complex and expensive, and cannot measure latent heat, specific heat and thermal conductivity of multiple PCM samples simultaneously. The weakness of the calorimetry method is the process of changing the two phases of PCM that is difficult to observe. T-history method that uses simple equipment has been widely used at this time. In this research, we will use T-History method to measure the thermophysical properties of phase change materials that will be used as heat storage material in solar water heating system. The material is: paraffin, beeswax, cow fat, and mixture of the material with a certain ratio. From the test, results can be concluded that the use of T-History method gives good results with a difference of 7% with the measurement results using DSC.

Generally, the foam concrete that designs as the current building wall is without considering the heat absorbent. Therefore, it is necessary to find additional materials that able to absorb the heat energy. One of them is Phase Change Material (PCM). Beef tallow is an organic material of PCM that has a high heat storage capability. Commonly, an aggregate requires in the manufacture of foam concrete as reinforcement materials. This aggregate can be changed with macro-encapsulation of PCM. This study aimed to find the ability of foam concrete based macro-encapsulation of beef tallow/damar gum in absorb heat energy that will be applied in building walls. This research was conducted experimentally with the primary materials of cement, fine sand, water, foam agent, catalyst, sika, and macro-encapsulation of beef tallow/damar gum. This foam concrete wall was made with the dimension of 80 x 80 x 10 cm and varied with a mixture of beef tallow / damar gum of 0%, 1%, 3%, and 5%, respectively. The wall concrete heater was simulated with using four lamps with the power of 200 watts. The type-K thermocouple was placed on samples at 2 points, inside and on the surface, which connected with Agilent 34970A. The results showed that the effect of adding PCM resulted in a decreasing of the temperature inside and on the surface of foam concrete walls. The amount of temperature decreases due to the addition of 5% PCM is from 51.9 °C to 44.7 °C or decreased by 13.87% inside of foam concrete walls and 75.64 °C to 51.9 °C or down to 21.87% on the surface of foam concrete walls. Overall, this foam concrete based macro-encapsulation of beef tallow/damar gum is better to use as heat-absorbent in building wall application compare with foam concrete wall without using macro-encapsulation of beef tallow/damar gum.

High number of preterm births is one of the issues in improving health standard. The effort to help premature babies is hampered by high cost of NICU care in hospital. In addition, uneven distribution of electricity to remote area made it hard to operate the incubator. Utilization of phase change material beeswax to non-electricity incubator as heating element becomes alternative option to save premature babies. The objective of this experiment is to investigate the most efficient mass of beeswax according to Indonesian National Standard to earn over time and ideal temperature of incubator. Experiment was performed using prototype incubator, which utilizes natural convection phenomenon in the heating process of incubator. Utilization of fin is to accelerate heat distribution in the incubator. Result of experiment showed that the most efficient mass of PCM is 3 kg, which has 2.45 hours of running time for maintaining temperature of incubator in range of 32-36 °C.

Cooking, a fundamental human necessity, frequently relies on environmentally harmful energy sources. Concentrated solar power offers a promising solution through solar cookers to address this issue. This study assesses a Parabolic Trough Collector (PTC) solar cooker's performance with two reflector materials: chrome stickers and glass mirrors. The PTC-type solar cooker comprises essential components, including an absorber tube, a flexible conduit, and a spiral-shaped cooking container holder that accommodates a diverse range of cooking vessels. In the configuration of the PTC collector, reflectors fabricated from chrome stickers and glass mirrors are strategically employed to harness and concentrate solar radiation effectively. The absorber tube, crafted from copper, is filled with a heat-transfer fluid consisting of soya oil. Experimental investigations were conducted in a two-stage process, encompassing trials without any applied load and subsequently with varying loads. In the no-load experiments, alterations were made to the PTC collector's inclination angle, spanning the ranges of 15º, 20º, 25º, and 30º. In contrast, the load-bearing tests encompassed the assessment of the PTC solar cooker's performance under a diverse array of cooking scenarios, including boiling water, heating oil, frying eggs, and crisping crackers. The evaluated parameters encompassed key metrics such as incident solar radiation (I_r), ambient temperature (T_a), receiver temperature (T_r), fluid temperature (T_f), spiral furnace temperature (T_sf), and load temperature (T_o). Subsequently, the outcomes of the experiments were employed to determine the efficiency of the solar cooker. Analysis of the no-load test results indicates that the most favorable performance, as observed in the parameters T_r, T_f, and T_sf, is achieved at a collector inclination angle of 15º for both chrome sticker and glass mirror reflector materials. The solar cooker demonstrated commendable proficiency in boiling water, heating oil, frying eggs, and crisping crackers, accomplishing these tasks within a time frame ranging from 5 to 20 minutes. Notably, the solar cooker featuring the glass mirror reflector exhibited a superior thermal efficiency of 33.7%, surpassing the efficiency of the counterpart with the chrome sticker reflector, which registered an efficiency of 30.9%. These findings underscore the efficacy of the glass mirror reflector in harnessing solar energy for enhanced cooking performance within this solar cooker configuration.