This paper aims to study providing electricity and domestic hot water demand for a single-family house in Basra city, south of Iraq. Three systems have been simulated by TRNSYS16 software to determine their thermal and electrical performance: traditional house (without PVT), with the PVT/water-based and with the PVT/0.4%Al2O3 systems. The annual energy consumption, collected energy, auxiliary energy, thermal solar fraction and domestic hot water have been analyzed in long-term simulation. The results show that the use of the PVT/water and the PVT/0.4%Al2O3 systems combined with the house decreased the annual energy consumption by about 43.54% and 52. 33% compared with the traditional house. The results also established that when using the PVT/0.4%Al2O3 system, the collected energy increased by 17.12%, while the auxiliary energy decreased by 31.51% compared with the PVT/water system. It is also concluded that using both the PVT/Al2O3 and the PVT/water systems with the traditional building covered the domestic hot water demand at about 42% to 100%, and 46% to 100% in various months, respectively. Finally, the results highlighted that there is an improvement in the thermal solar fraction of about 14.5% in the case of using the PVT/Al2O3 system compared with the PVT/water) system

The main part of the solar heating system is the solar collectors, the most common of which are the flat plate collector and the evacuated tube collector. In domestic use, solar hot water systems based on flat plate collectors are used more because of their low cost and minimal maintenance. Also, the outlet temperature of the collector corresponds to most domestic hot water needs. Solar hot water systems' performance varies with environmental conditions changes (atmospheric temperature, solar radiation, wind speed). This article modeled an indoor solar hot water system using Transys software. This modeling is the development of a solar hot water system model based on an active flat plate collector. The developed model can predict the performance of the solar hot water system for different climatic and seasonal changes in the year. The system's long-term performance for Iranian weather conditions is evaluated and presented in the paper. Performance parameters such as the functional energy efficiency of the collector and hourly and monthly thermal efficiency are presented and discussed. Among the simulation results, it can be mentioned that the solar hot water system with a collector area of 5 square meters can meet more than 70% of the 400 liter needs of a household in Ahvaz, Iran.

In order to reduce energy consumption in air conditioning and refrigeration systems, in this research, a system based on the vapor compression refrigeration cycle and ground energy use has been proposed. This system centrally supplies the energy needed for the air conditioning unit, refrigerator and freezer of a building. The condensing unit of this system is cooled separately and in series by two heat exchangers using outdoor air as well as ground energy. The energy consumption for a sample building is simulated by analytical calculations as well as the use of HYSSIS and Transys softwares. The results of the calculations, which include the system performance coefficient, compressor power consumption, refrigerant quality and mass flow rate, have been compared with the values ​​of the conventional system. The results show that using the water cooled condenser unit, the inlet refrigerant temperature to the reducer valve is significantly lower than the outdoor air temperature. This significantly increases the performance of the proposed system and significantly reduces the refrigerant mass flow rate. The effect of reducing the exit refrigerant temperature of the condensing unit on the exergy of the refrigerant has also been investigated.

In order to supply the thermal load of a building, a huge amount of energy is consumed. Therefore, it is necessary to use renewable energy sources in today’s architecture. As a matter of fact, this issue has begun to be the focus of many studies worldwide making the topic even more interesting. In this regard, the wind has always been known as an outstanding renewable source of energy used in Iran for thousands of years. Windcatchers, known as Badgirs in Iran, are notably used in warm-humid and hot-dry climates to make the best use of wind energy in these areas. However, Badgirs are neglected in today’s life due to the limitation associated with their use in modern buildings. Accordingly, the current study aims to take into account some advantages of the windcatchers (Badgirs) in addition to highlighting their effect in both reducing energy consumption and providing thermal comfort. In previous research, humidification and similar solutions have been used to provide cooling and heating by a windcatcher, however, in none of them the Ground source heat pump system has not been used for this purpose. This study proposes a system consisting of a windcatcher and a Ground Source Heat Pump system for a building in Yazd, Iran. For this purpose, the study is conducted in three steps. First, current literature is studied. Second, the proposed system is simulated using Transys software. Finally, a mathematical calculation is performed. The simulation model consists of a room located in Yazd with width, length, and height of 4m, 6m and 3.5m, respectively. The findings show the positive effect of the proposed system in improving thermal comfort and energy by about 37.6% in summer and 7% in winter.