The inclusion of baffles in a double pipe heat exchanger is becoming increasingly important as it improves the heat exchanger's performance. The CFD analysis is used in this paper to investigate the performance of double pipe heat exchangers with and without helical baffles on both shell tube sides. The 3-D CFD model was created in Solid Works, and the FloEFD software was used to analyze the conjugate heat transfer between the heat exchanger's tube and shell sides. Heat transfer characteristic like outlet temperature of shell and tube are investigated along with pressure drop on shell and tube side. Based on CFD results of double pipe heat exchanger with helical baffle on both shell side and tube side (Type 4) gives the better results than the other type of heat exchangers with an increased pressure drop than the others, results reveals that Type 4 outlet temperature of shell side is 8% higher and on tube side it is 5.5% higher, also pressure drop on shell side is 12% higher and on tube side it is 42% higher than the other types.

Due to the increasing demand for air conditioners to maintain thermal comfort in buildings, it is necessary to search for alternatives that can reduce the soaring temperature and meet total air conditioning demands. There are several proven technologies for maintaining thermal comfort in buildings of which the use of phase change material (PCM) in buildings provides improved thermal comfort with fewer energy requirements. The present study analyzes the impact of the incorporation of PCM in roofs on the thermal behavior of buildings. The experiments were conducted in two identical model building roofs with and without the implementation of PCM. A numerical model was developed to find the effect of variation in the PCM layer thickness and month wise temperature variations. To get minimum variation in the results, the simulation was run continuously for 5 days assuming average climatic conditions. The results showed that temperature fluctuations in the room were reduced with the use of PCM, and also the average peak temperature rise was reduced by 2–4°C. The increased PCM layer thickness resulted in decreased energy demand for maintaining the required thermal comfort in buildings at an almost constant temperature.

This work is a performance study that investigated the nanorefrigerant CuO/AL₂O₃-R22 used in a refrigerator without any remodelling of the system. The refrigerator performance was then investigated using energy consumption test and enhancing heat transfer rate. The heat transfer enhancement was investigated on the surface of a refrigerator by using the nanorefrigerant Al₂O₃/CuO. The results indicate that CuO-R22 works normally and safely in a refrigerator and has better power consumption and heat transfer rate. Thus, using CuO-R22 as nanorefrigerant in domestic refrigerators is feasible for better heat transfer rate.

Though the biodiesel is environmental friendly than the conventional petroleum diesel in the aspects of better combustion quality due to higher cetane number (up to 65), reduced emission, and reduced air pollution, running the common rail direct injection (CRDI) engine with 100% biodiesel is not viable due to NO_x and CO emissions. The present experimental investigation revealed that the above difficulty can be controlled by running CRDI engine with air nanobubble (ANBs)-enabled biodiesel. The results indicated that there was a reduction of 25% in brake-specific fuel consumption, 33% in NO_x, and 16% in CO due to the addition of ANBs with mustard oil biodiesel.

The concept of thermal energy storage in building gains a specific importance in the present energy scenario related to energy consumption and indoor thermal comfort. The material used to store the thermal energy which undergoes a phase change referred as PCM and it is considered as a possible solution for reducing energy consumption in the building by storing and releasing heat within a certain temperature range; it raises the building inertia and also stabilizes indoor air temperature fluctuations. The room temperature is controlled by imposing PCM inside the walls. An attempt has been made to compare room air temperature with and without the use of PCM inside the walls of constructed modular building unit. The PCM imposed modular building shows the reduced temperature fluctuations in room, the PCM absorbs and liberates excess heat which is gained from the outer side of the room and maintains constant inner room temperature. The PCM imposed walls of modular building unit have an ability to reduce 10–30% of heat load in comparison with the plain wall. The results showed that reduction in room temperature is about 2–4°C and it has been concluded that the PCM imposed modular building unit has more energy saving opportunities than normal modular building unit.