Today, the usage area of metal matrix and ceramic reinforced composites is increasing and researches in this field are increasing. However, majority of the studies conducted are constituted of studies on investigation of mechanical features of composites. One of the reasons why composite materials are preferred is because these materials have improved thermal property. With this experimental study, it is aimed to contribute to the literature in the area of investigating features of thermal properties. In this study, composite materials were produced at 500 °C, 550 °C and 600 °C sintering temperatures by adding 4%, 8% and 16% B₄C to Al 1070 quality aluminium by powder metallurgy technique. Firstly, the microstructures of the composites were investigated. Then, experiments were conducted to determine the specific heat of composite materials at different ambient temperatures together with thermal conductivity measurements. With the data obtained from the experiments, finite-element modelling was done and the thermal properties of the composite structure were optimised. In the microstructure studies, it was determined that with the increase in the B₄C reinforcement ratio, the reinforcement agglomeration and porosity in the composite structure were found. As a result of the thermal experiments, it was observed that the thermal conductivity values of the composites were inversely proportional to the amount of B₄C reinforcement and as the reinforcement ratio increased, the thermal conductivity values decreased. Besides, it was determined that the sintering temperature has an effect on the thermal conductivity value and that it increases the thermal conductivity of the composites with increasing sintering temperature. The highest heat conduction coefficient was obtained at 4% B₄C reinforcement ratio and 600 °C sintering temperature. It was observed that the finite-element models prepared to determine the heat conduction coefficient effectively were consistent with the experimental results.

This study conducted a thermodynamic analysis of an air-source heat pump using R32 refrigerant to assess its effectiveness in meeting the heating needs of a residence in Kırıkkale province during winter. The air temperature in Kırıkkale was obtained from the Turkish State Meteorological Service according to the average of last ten years. Calculations were based on the heating season between October and April for the years 2022-2023. In the study, parameters such as heat gained from the environment, compressor energy consumption, the system's performance coefficient, and second-law efficiency have been examined. As the external air temperature decreases, the amount of gained heat decreases by approximately 9%. In this regard, the energy consumption of the compressor to meet heating demand has increased by approximately 40%. The results showed that the system performance was calculated as 5.545 and 3.957 for October and January, respectively. However, the second-law efficiency was observed to be 0.3266 for January and 0.2103 for October. The findings emphasize the varying performance of air-source heat pumps depending on climatic conditions.

In this study, the effect of ulexite substitution in cement mortar and its physical and mechanical properties on cement mortar properties were investigated. First of all, the pozzolanic activity of the ulexite material was determined. Then, cement mortars with ulexite additives at different rates (0.5%, 1%, 2%, 4%); Specific gravity, specific surface, setting start and end times, consistency and expansion tests, as well as 7 and 28 days flexural and compressive strength of the mortar samples were determined and compared with the control sample. As a result of the study, with the increase of the ulexite substitution ratio, the set start and set expiration times were extended, and all of the ulexite-substituted cement mortars provided the lowest mechanical strength required in related standard. It was observed that the cement mortars with 0.5%, 1%, 2% ulexite substituted cement mortars exceeded the reference sample and the best replacement rate was in the mortars with 0.5% replacement. However, depending on the increase in the ulexite substitution ratio, a decrease in mechanical strength was detected among themselves. According to the results obtained from the thermal conductivity tests, the thermal conductivity values of the cement mortars decreased with the ulexite substitution. Depending on the ulexite substitution rate, the thermal conductivity value decreased by approximately 50%. The lowest thermal conductivity value was measured in the test sample with 4% ulexite substitute.