Phase change materials (PCMs) have emerged as promising solutions for latent heat thermal energy storage (LHTES) systems, offering considerable potential for storing energy derived from renewable sources across various engineering applications. The present study focused on optimization of solar cooling system by integrating LHTES with different PCM tank configurations. TRNSYS simulation software was selected for the study, and the collected experimental data from laboratory system prototype were used for system validation. The results indicate that the use of PCM led to a noteworthy decrease of 6.2% in auxiliary energy consumption. Furthermore, the time during which the heat carrier temperature flow exceeded 90 °C from the storage tank to the auxiliary fluid heater was extended by 27.8% when PCM was utilized compared to that of its absence. The use of PCM in LHTES is more effective under variable weather conditions. On the day when changes in weather conditions were observed, around 98% of the cooling load was provided by produced sun energy. The results of the research can be used to optimize the solar cooling system, which will help reduce the environmental impact of cooling systems running on non-renewable fuels.

Temporary structures are being extensively used by emergency services (rescue, disaster relief, military response units), and other end-users requiring temporary mobile off-grid energy solutions for different purposes (event organization, vacation homes, summer camps, etc.). Yet energy systems for these purposes largely remain fossil-based (such as diesel generators). Although such energy systems are inexpensive, they are carbon intensive and inefficient. This study presents a methodology of simulating temporary shelter with access to an energy supply system through a mobile energy unit with renewable (PV) power supply systems to ensure on-site electricity production, as well as heating/cooling and ventilation. Digital modeling simulations have been performed for a simulated temporary shelter in different climate conditions incorporating different combinations of electricity generation systems with a fossil fuel-based solution and a PV system, using TRNSYS software. Study results show that the operation of a mobile energy generation unit can operate HVAC systems and generate electricity for temporary shelter occupants in off-grid solutions. The modeling results show that the use of a mobile energy generation unit can significantly reduce diesel consumption in temporary shelters from 54% annually (in Riga, Latvia) to 96 % annually (in Jerusalem, Israel). Furthermore, the output of PV-generated electricity is higher (in most cases) than the consumed electricity amount.

The European Union sets targets for the extensive use of renewable energy. Meanwhile, the energy production network is changing and transferring from the classic “producer to consumer” scheme to new operation models, where a small consumer with local renewable energy systems becomes a producer–prosumer, an active energy consumer who is also an energy producer. This study evaluated a potential of Latvian households’ participation in the energy market as prosumers. The analysis was based on an informal prospective extrapolation data evaluation method, based on real historical data from the Central Statistical Bureau of Latvia, annual reports of distribution and transmission system operators, assessments, and the conclusions of relevant experts. In addition, the real performance of a photovoltaic (PV) system was evaluated to get information on the whole year’s energy balance, and to compare it with seasonal electricity price fluctuation. The Latvian electricity transmission system is able to accept about 800 MW of additional new renewable energy source (RES) capacity, so there is a great potential for prosumers. The biggest obstacle for a household’s involvement in the energy market is the lack of support mechanisms and relatively high cost of RES technologies. The results show that with the current dynamics of new microgenerator connections, Latvia will achieve the set goals regarding the involvement of prosumers in the achievement of RES goals only in the next century. In order to attract the public to energy production, the concept of energy community needs to be defined in Latvian legislation, a balanced peer trading mechanism needs to be developed for various RES self-consumption groups willing to sell surplus electricity, and tax policy conditions need to be reviewed for electricity transactions outside the NET (payment system), in order to fully ensure the rights of prosumers.

The use of air conditioning technology is accompanied by an increase in electricity consumption, which is linked to an intensification of fossil fuel extraction. This in turn calls for developing cooling solutions of higher energy efficiency. The aim of this study is to examine energy consumption reduction of direct evaporative cooling technology for generating cool air in hot-dry climate regions. At the initial stage, already-installed air cooling equipment with a direct evaporative cooling system was studied for the creation of two regression models of electricity consumption representing the “on” and “off” sequences. Water consumption for system operation was taken into consideration. In the following stage, inlet water temperature dependence for pre-cooling purposes for the direct evaporative cooling system was studied. A mathematical model was developed and the subsequent calculations suggested that there is no need to pre-cool water before it enters the system and therefore consume additional energy. Practical application of this study is evaluated based on the case study in Dubai. The results of this study present significant energy saving potential for system operations of the direct evaporative cooling system of approximately 122 MWh per year. The return on investment for the equipment with direct evaporative cooling in case of an office building in Dubai featuring a hot desert climate is around 4.2 years. The purpose of this study is to examine the potential advantage of air cooling equipment with direct evaporative cooling technology compared to cooling equipment without this technology. The results provide the expediency of conducting further research in this area, in particular with regards to analyzing various materials for the adiabatic precooling pads, as well as the possibility of using a newly developed metal precooling pad.