Maximizing the quantity of heat delivered to the air is one of the difficulties dealt with by solar collectors used for air heating. In order to increase the quantity of heat delivered by the phase change materials with integrated nano materials, a thermal insulation solution is investigated in this work to reduce losses to the adjacent regions. A mobile insulating blanket that is fully mechanized is the solution. The time of day or the season determines where to set the insulating blanket.

As in 1973, the energy issue occupies the first page of the agenda of energy experts, social planners, politicians and, last but not least, consumers. The impact of renewable energy sources (wind and solar) on the energy infrastructure was analysed, while aiming to reduce carbon footprints. Demographic growth, urbanization, the targets imposed by Net Zero Emissions tend towards the massive forcing of energy towards renewable energy conversion and storage systems

Energy efficiency norms require effective insulation techniques for buildings in order to minimize energy consumption. The paper presents simulations, carried out throughout the year, regarding the efficiency of energy recovery units (ER) to ensure the quality of fresh indoor air. Indoor air energy recovery calculations were performed using plate and rotary heat exchangers in different operating scenarios. The evaluated parameters led to the stability of the optimization solutions in order to obtain a higher energy efficiency on the equipment. By comparing the obtained results, optimal measures and solutions were identified for energy efficiency in the operation of ER

The current trends converge towards minimizing the carbon footprint on the environment in the operation of all thermal equipment and need finding alternative solutions compared to what the market offers at the moment. Utilizing hydrogen in combustible mixtures with methane gas to fuel condensing boilers is one solution. The benefit is that it reduces carbon dioxide emissions into the atmosphere as only water vapor is produced when hydrogen undergoes combustion. The effects of adding hydrogen at percentages of 23%, 30%, 35% and 45%, respectively, to the combustible gas mixture are examined in the paper

In a residential building, the integration of thermal modules from the design phase can bring multiple benefits in terms of energy efficiency and thermal comfort. The article deals with a brief comparison between the traditional heating system and the decentralized system with apartment thermal modules by making the preparation of the thermal agent for heating and domestic hot water more efficient. The study was carried out following the new nZEB requirements regarding the obligation for all new buildings and those undergoing renovation to ensure a percentage of at least 30% from renewable sourcess

This paper investigates the opportunity of utilizing the heat recovery from refrigeration systems in supermarkets with medium requirement capacity for air conditioning. The electricity consumption for air conditioning and refrigerated cases in medium supermarkets represents an important share of the total electricity consumption. The energy efficiency of supermarkets can be improved by optimizing components design, recovering energy, adopting innovative technology solutions, integrating the HVAC system with medium temperature and low-temperature refrigeration plants. This study is aimed at investigating the energy consumption of a refrigeration system for commercial refrigeration and air conditioning that uses the refrigerant R410A. Two refrigeration systems are analyzed: - traditional solution: system for commercial refrigeration using equipment type ZEAS + air conditioning equipment type VRV IV; - new proposed solution: system for commercial refrigeration with heat recovery using equipment type Conveni-Pack for air conditioning. The results obtain shape the potential for improving energy efficiency and environmental impact over traditional system in climates from Romania. The investigated solutions allow an annual energy saving higher than 17% to the baseline solution for the considered climates.

The external temperatures BINs are a couple of components, the external air temperature, te, representative of a relatively small range of values and the duration of appearance of these external temperature values within each month of a year. The establishment of these couples assumed an analysis of the behavior of the outside temperature throughout the whole year but also during each month of the year and also of daily oscillations within each month. It resulted as a representative number of 5 BINs per month and in this hypothesis the monthly BINs were established. It turned out that the locality in Romania has a distinct importance in the effective establishment of the BINs, which is why they are different depending on: locality, month of the year, average monthly outdoor temperature and the amplitude of the daily oscillation of the outdoor temperature. The external temperature BINs are useful in energy analysis studies on buildings for utilities such as space heating and the preparation of daily hot water, an example being the implementation of an air-water or air-air heat pumps

Considering the fact that the energy sector producing both thermal and electrical energy has a contribution to the increase of greenhouse gas emissions, the need to diversify energy production sources and equipment such as biomass power plants, installations that recover secondary fuel and thermal energy resources, solar installations and heat pumps is a major priority. The study carried out presents a solution for the integration of renewable energy sources (RES) for the production of electricity that will then be used both in the own thermal energy supply facilities, following that the surplus electricity will be used for the production of hot water that can be delivered in the district heating system

The study on refrigeration systems in this paper was made at the Technical University of Civil Engineering of Bucharest (U.T.C.B) - Colentina Laboratories Complex. The chosen topic is aiming to contribute to the theoretical basis and practical research in terms of development and use of ecological refrigerants. In the last ten years, a lot of research has been done in the field of ecological alternative refrigerants , at international level, taking into consideration the severe legislation restrictions stipulated by law: Kyoto Protocol, Regulation (EU) 517/2014, Paris Agreement / 2015, Kigali Amendment / 2016 / Montreal Protocol. In respect of this, the research, considers the implementation of EU legislation in the field of refrigeration systems, heat pumps and air conditioning

The paper presents the analysis of the current situation and the tasks for the effective organization of the fiscal measurements of the volumes of natural gas supplied to household and utility consumers in the context of the requirements to reduce natural gas losses in the distribution networks of JSC "Moldovagaz". In this sense, a study of the errors of the measuring equipment operated in the range of reduced thermal loads of the devices of consumption is presented, which places the measurements in the range of uncertainty after 3 years from the regulatory metrological verification, and after 5 years and 7 years - conditions errors with "minus” in the amount of up to 10% and 20% respectively of the measured volume, a fact that conditions natural gas losses for distribution system operators. In this line of ideas, scenarios are being sought to optimize the activity of metrological laboratories so that the installations are operated at the nominal load (10 thousand meters / year), the transport radius of the meters for metrological verification is placed within the limit of up to 70 km, and their duration of operation between two successive regulated checks not to exceed 5 years. Conclusions are structured on the edge of the proposed solution, which include the technical aspects and the economic advantages of optimizing the activity of metrological verification of the meters of final household and utility-household consumers.