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.

In recent years construction of bullet resistant walls has become very common not only for military buildings but also for public and residential buildings. The existing wall structure in those buildings is reinforced by ballistic panels. However, in the cold climate regions external application or installation of the ballistic panels can cause interstitial water vapor condensation. Also, an incorrect application of such panel on the internal surface can lead to an insufficient drying of the structure during the summertime. This paper presents an analysis of thermodynamic properties of ballistic panels. For this purpose, laminated and non-laminated ballistic panels were examined. Thermal conductivity features such as water vapor permeability were evaluated in laboratory conditions. Based on gathered results the DELPHIN simulation software and THERM calculation tools were used to analyze the thermal resistance of wooded frame wall reinforced with ballistic panels. The obtained results were validated under controlled environment. Temperature and moisture measurements were performed inside the tested wooded frame structures reinforced by ballistic panels under different internal and external air parameter fluctuations.

The aim of the study is to analysis renovation solutions for unclassified buildings. According to Latvian law definition, unclassified buildings are prisons, security forces, police and fire services buildings including barracks, warehouse etc. Such buildings has completely different heat gains and heat losses balance and usage profile in comparison to traditional public and apartment buildings. Unclassified buildings could have higher internal heat and moisture loads, more strict requirements to dress code (CLO level), human metabolic equivalent and limited possibility for staff adaptation to IAQ parameters. The one of important factors is safety of energy supply and operation of HVAC systems. Although the energy security is a top priority for unclassified buildings, it should not be a barrier for implementation of renewable energy sources and innovative energy efficient retrofitting solutions in unclassified buildings.

Temporary shelters are extensively used by emergency services (rescue, disaster relief, military response) and other end-users requiring temporary mobile power solutions for different purposes (event organization, vacation homes, summer camps, etc.). The Covid-19 pandemics resulted in an increase of motor homes worldwide sales. When temporary shelter connection to power grid is impossible, the off-grid liquid fossil fuel generator can be used for electricity generation. Since the liquid fuel supply is often limited, the stock of fuel requires storage that may pose an explosion risk. Quickly installable and energy-efficient ventilation / cooling system with heat recovery is essential to ensure adequate air hygiene and occupants’ comfort in temporary structure. This paper presents a mobile modular electric energy generating unit with photovoltaic (PV) panels for providing temporary shelters (tents) in Latvian climate conditions with heating, ventilation, and air conditioning (HVAC). All calculations were performed using the computer model developed with TRNSYS tool and based on real data from mobile modular energy unit for spring, summer and autumn 2020 and winter 2021. The results show that mobile modular energy unit can be successfully applied for off-grid HVAC system operation of temporary shelters in the Latvian climate conditions.