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Currently, approximately 40% of the energy demand in the European Union (EU) is used in buildings and the energy demand for cooling and heating is increasing every year, so the energy efficiency of buildings represents a problem of increased interest and of extreme relevance. The article proposes, through the case study, the installation of a photovoltaic system for the production of electricity on the roofs of the buildings and the cooling and heating of the building using a water-to-water heat pump. Having the advantage of the location of the studied buildings on the banks of the river Bega in the town of Timisoara, the case study proposes the cooling of the spaces in the buildings in two variants, namely in the spring and autumn when the outside temperature is not very high using the river water directly ("free cooling"), and in the summer for the hot months, a water-to-water heat pump to cool the cooling agent to the parameters necessary to achieve a proper air conditioning. [ABSTRACT FROM AUTHOR]

Currently, many opportunities for real energy and cost savings are missed, primarily due to the perception of quantitative heat recovery. However, in the context of the need for the energy efficiency of buildings and technological processes, the recovery and valorisation of residual energy will be a key element. For this reason, the article analyses the recoverable potential from residual energy from various sources and proposes a way to capitalize on it for heating/cooling buildings and preparing domestic hot water. [ABSTRACT FROM AUTHOR]

In close connection with the issue of global security, the issue of ensuring energy resources has been put on the table of consumers and producers of various forms of energy, researchers, but especially politicians and social planners. Ensuring energy independence was put into question after the onset of the oil crisis in 1973, thus the various energy sources and their associated technologies are gradually being replaced by new technologies that integrate renewable energy sources, capable of taking over at an increased level of efficiency the energy requirement. [ABSTRACT FROM AUTHOR]

The study was carried out to evaluate theoretically and in laboratory conditions the capacity of a hybrid heating and cooling system that sustainably uses thermal energy extracted from surface waters in order to decarbonize buildings located near water sources. The novelty of the research consists in the realization of two experimental systems, one for the rapid evaluation of the performance of the water–water heat pump heating system and one for the evaluation of the operating behavior of a cooling system with fan coil units. Starting with the heating and cooling demand, and the climatic and hydrological local characteristics, a hybrid system model for the heating and cooling of the analyzed building was established and implemented. The forecasted energy consumption and CO2 emissions for the operation of the new equipment were compared with the historical values of the old systems with which the building was equipped (thermal energy supply from the district heating and cooling system with an air conditioning unit). Also, the results were extrapolated for forecasting the energy potential of the surface waters. The study highlights a percentage reduction in annual energy consumption of 67.71% and CO2 emissions of 80.13% through the implementation of the hybrid system. [ABSTRACT FROM AUTHOR]

The building sector is one of the largest final consumers of energy, especially for air conditioning, and research has shown that there is a great potential for energy savings in this sector. The performance of a chiller can vary significantly depending on system partial loads and evaporator and condenser operating temperatures. The condensers of water-only chillers take the heat of condensation from the refrigerant only through the sensible heat of the refrigerant, leading to significant water flows. The outside air temperature and the intensity of solar radiation directly influence the consumption of electricity on the chiller. Having available the values for the solar radiation intensity I [W/m2 ] and the outside air temperature te [⁰C], with the help of the proposed mathematical model, validated by experimental measurements, the optimal values for the minimum electricity consumption of the system are obtained, under the conditions which the chilled water temperature is 7/12⁰C and the indoor air temperature is 27⁰C [ABSTRACT FROM AUTHOR]

Underfloor heating systems ensure maximum comfort through optimal vertical temperature distribution, and the possibility of exact control and programming of the indoor climate. Used as a total heating source, the underfloor heating system will provide all the heat requirements of the space to be heated, provided that the external walls are properly insulated. In the study, two underfloor heating systems were analyzed using the dynamic simulation feature of the HTflux software. Following these simulations, temperature differences will be observed in front of the floor finish depending on the type of system used. The wet screed system heats up significantly faster and reaches a higher temperature by approximately 4.5% compared to the dry screed system. [ABSTRACT FROM AUTHOR]

The indoor air quality in bedrooms is one of the main factors that influence the human performance during these days. Throughout the years, a lot of studies described the relation between the climate comfort and the performance. This study presents the important factors to have a quality sleep with the main effect being daily productivity. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In an existing office building, integrating air-to-water heat pumps into a district heating system can bring multiple benefits in terms of energy efficiency and thermal comfort. The article deals with the implementation solution for the efficiency of district heating systems, exemplified by a case study related to an existing office building. The study was carried out following the multiple breakdowns that occurred in the thermal energy distribution system from the district heating company, as well as the interruption of thermal energy for long periods of time. [ABSTRACT FROM AUTHOR]

The increase in global temperature and the current energy context have brought the district heating system in Timișoara (partialy renovated) to the brink of collapse. Therefore, major investments and orientation towards the integration of renewable energy sources (RES) are required. The article analyzes, by exemplifying a case study, the integration of photovoltaic technologies at a heat point that supplies the buildings of the Faculty of Construction (CT) in Timișoara. The study was carried out with the help of Polysun software. The results obtained indicate a reduction in thermal and elctrical energy costs of 38.51% by installing a number of 1095 photovoltaic (PV) panels on the roof of 4 building bodies (ASPC, Deposit, CT and Metal). [ABSTRACT FROM AUTHOR]

In the context of the acceleration of the need to store and process data and digital telecommunications, which leads to an increase in global electricity consumption and greenhouse gas emissions, the need for research to find reliable, efficient, and cost-effective solutions to reduce energy consumption and the recovery of the residual heat produced by the data centres is an increasingly urgent one. The article presents aspects that refer to the recovery of residual energy from data centres and its use for the preparation of domestic hot water, but also for the preparation of the thermal agent necessary for heating installations in buildings and respectively modern heating systems, with the mention that the latter work at a low temperature regime. [ABSTRACT FROM AUTHOR]

Northeast China has been facing a severe power shortage situation. Since September 2021, "power rationing" events occurring in many places in the three provinces of northeast China have been causing inconvenience to people's production and life. Therefore, it is particularly important to accurately predict the power load combined with the influencing factors of local power consumption. At the same time, the northeast region is about to enter the heating season, and the pressure on coal and electricity will further increase. In Heilongjiang Province, due to coal capacity control, limited production led to the high price of thermal coal; wind power photovoltaic output fluctuations, the epidemic, and other reasons also resulted in a large gap in the power supply side. Improving the power demand forecasting ability is of great significance to strengthen the reliability of people's daily electricity consumption, rational distribution of power generation plans, and deployment of power grid resources. In order to improve the accuracy of electricity consumption prediction in Heilongjiang Province, Markov error correction is carried out on the basis of the backpropagation (BP) neural network prediction model so that the final prediction results have the advantages of the BP neural network prediction model and Markov model. In addition, it is more suitable for the prediction of random series data with high volatility, the prediction accuracy can be improved significantly, and the overall trend of electricity consumption can be predicted more accurately. [ABSTRACT FROM AUTHOR]

Copyright of Romanian Journal of Civil Engineering / Revista Română de Inginerie Civilă is the property of Matrix Rom and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The study analyzes the benefits of implementing automatic transfer systems of the main electricity supply with one or more backup supplies in the event of a breakdown caused by a fire or other unforeseen events. Transfer switch using relays as phase failure protection is a gear switch control system with the main purpose of transferring load between a primary source (Public Utility) and a secondary power supply sources (Generator1 and Generator2) which are stand by power sources and eliminating frequent manual switching of change over device when there is power outage. [ABSTRACT FROM AUTHOR]

The indoor air quality is one of the main factors that influence the thermal confort and, consenquently, the human performance inside buildings. Throughout the years, a lot of studies described the relation between the climate confort and the performance .This study follows the thermal sensations of students in a seminar room during the summer and winter periods and presents the results between them. [ABSTRACT FROM AUTHOR]

In the context of the acceleration of the transition process from refrigerants with high global warming potential (GWP over 1500 units) to refrigerants with low global warming potential, within the limit of 150 units according to the F-GAS regulation, the refrigeration industry has difficulties in the development of refrigerants that meet safety standards (class A1L – non-toxic and non-flammable), environmental standards (GWP-under 150 units), efficiency standards (COP) and long-term viability. The study shows that slowly but surely, refrigerants are starting to appear that meet all these regulations and that can be integrated into commercial installations of small and medium power up to 50kW. Based on the versatility of the refrigeration plant components, starting with the compressor, the condenser, the evaporator, continuing with the refrigeration automation and ending with the command-and-control automation, the article wants to show that, very soon, we can choose technical solutions that comply with the current requirements. [ABSTRACT FROM AUTHOR]

The paper presents a study on the efficiency of installing photovoltaic blinds in a didactic laboratory with large glased surfaces, in order to ensure the shading of the interior spaces and to avoid the use of air conditioners during warm periods of the year, as a contribution to the passive house concept. [ABSTRACT FROM AUTHOR]

The buildings sector is responsible for the largest percentage of total energy consumption, especially for heating and cooling. For this reason, the paper compares two heating/cooling systems (multisplit VRF and respectively chiller, central heating and fan coil units) for an office building. Energy consumption for heating/cooling, domestic hot water preparation and lighting, expressed in MWh/year, was analyzed. Following the simulation, the VRF air-conditioning system, which registers a global consumption of 70.23 MWh/year, compared to the system with a chiller, thermal plant and fan coil units, which registers a global consumption of 81.25 MWh/year, was found more advatageous. [ABSTRACT FROM AUTHOR]

The article analyses the variation of the vertically temperature gradient, in an industrial space heated with radiant tubes. Data monitoring was done with a workstation equipped with 5 high-performance temperature sensors. The temperature measurement was carried out in 5 distinct points inside/outside the production space, selected in different hypotheses, and a thermovision camera was used at the floor level. The values of the indoor air temperature measured at the level of the ankles, at the level of the work plane and at the level of the head of the people in the productive space fall within the normal limits. [ABSTRACT FROM AUTHOR]

The incontestable evidence of climate change and extreme weather events has brought the entire world to the brink of a red code alert, which determined the need to establish targets for limiting greenhouse gas emissions and the other actions that can be taken to solve them. The paper presents aspects of limiting the contribution of buildings to climate change through energy efficiency measures with an emphasis on the importance of the nZEB concept. The need to reduce the consumption of energy from fossil sources and increase the contribution of energy renewable sources is discussed, in a realistic context. [ABSTRACT FROM AUTHOR]

The paper aims to analyze the major influence of filters on the consumption of electricity in ventilation systems, especially in air treatment plants in accordance with ISO EN 16890. On-site measurements are made with the help of the air treatment plant within the HVAC laboratory, with a flow rate of 2700 m3/h, on two filters with dimensions of 287 mm x 592 mm x 500 mm. The results indicate an energy class C for the analyzed filter. As future directions of study for the achievement of energy efficiency within an HVAC system, simulation with the help of the TRNSYS software can be used, for different scenarios. [ABSTRACT FROM AUTHOR]

Considering the current energy context, with the increase in the price of natural gas and electricity, the use of renewable energy has recently had an increasing trend. In this sense, the article presents a case study for the energy efficiency of educational buildings, through the installation of photovoltaic systems and air-water heat pumps. The simulation was carried out with the help of the Polysun calculation program, analyzing the energy consumption of the ASPC building of the Faculty of Construction in Timișoara, in the existing situation and in the proposed efficiency stages. The results show that in the first stage of efficiency in which the photovoltaic PV system and the airwater heat pump are installed, a decrease in costs for the necessary thermal and electrical energy is achieved, by 42.36%. In the second stage, in which it is proposed to decrease the return/return temperature regime of the indoor installation from 60/40 ℃ to 40/30 ℃, the result is a decrease in the electricity consumption from the national network by 7.94%. [ABSTRACT FROM AUTHOR]

The current situation of Fluorinated Greenhouse Gases (F-Gas) Regulation and discussion regarding per- and polyfluoroalkyl substances (PFAS) gases problems with actual refrigerants from refrigeration installations with global warming potential (GWP) higher than 150 units will damage even more the environment. On top of the environment crises, caused by global warming and the Russia-Ukraine war, the prices of the energy increase more than 50%. So, this study shows that actual refrigerants like R404A, R448A, R449A and other refrigerants with GWP higher than 150 can be replaced for long term solution with CO2. [ABSTRACT FROM AUTHOR]

Given that water is an indispensable and valuable resource, the water shortage faced by some areas of the globe has recently attracted the attention of the European Environment Agency (EEA). For this reason, the paper deals with aspects regarding the possibility of using water from precipitation, taking into account, for the study, buildings from two rural localities adjacent to Timișoara (Giarmata and Moșnița Nouă). An analysis was carried out regarding the amount of drinking water that can be replaced in indoor sanitary installations with captured and stored water from precipitation. The amount of potable water that can be replaced was considered only for household needs such as: flushing toilets, washing clothes, watering green spaces and gardens and washing impervious spaces (lanes, yards, etc.) on the property. The study considered 5 stages of approach through which the quantity and quality of rainwater that can be collected, the technical solutions that can be implemented and the reduction of the amount of drinking water were evaluated, taking into account two consumption scenarios (reduced and increased). Based on the data obtained, it was concluded that for a low level of consumption, in the two buildings, the amount of water collected from precipitation fully covers the consumption of the household needs taken into account, and for the scenario of increased consumption, only 2 and 3 weeks of consumption remain uncorrelated which are the equivalent of a normal vacation period in which no consumption is recorded. In conclusion, the installation of rainwater storage systems is reliable for residential buildings, especially in rural localities where properties benefit from larger land areas. [ABSTRACT FROM AUTHOR]

One of the world’s topical issues is the necessity of energy consumption reduction in order to conserve less and less natural resources and protect the environment. The article deals with the need to develop the waste energy recovery solutions that reduce energy consumption among the industrial consumers. In order to identify the sources with recoverable potential and establish energy recovery solutions, thermography of the hot air and hot gas exhaust circuits from industrial technological facilities were performed, followed by monitoring the operation parameters and measuring the energy consumption. The energy consumption reduction is analyzed by comparative interpretations of the hourly consumption, before and after applying the optimal recovery solution. The analysis of the results revealed that the waste energy recovery during the technological facilities operation has, besides the economic benefit, also other positive energetic effects, technical and not at least ecological ones.

In view of the Directive 2006/32/EC of the European Parliament and of the Council of 5 April 2006 on energy end-use efficiency and energy services, it is requested, as a consequence, to ensure the Energy Audit of the building and propose energy improvement measures in order to access structural funds, inclusively for functional and structural rehabilitation. This article proposes to analyse the energy survey aimed at the issuing of the Energy Efficiency Certificate of the building, and finally the Energy Efficiency Audit of the thermally rehabilitated school building, in view of improving the energy efficiency of the building and of the related installations. [ABSTRACT FROM AUTHOR]

Due to the pressure that landfills have on the environment, the article deals with the possibility of recycling waste from abrasive water jet cutting machines (AWJCM) because this waste either takes the path of storage (abrasive sludge) or is discharged into public sewer systems (wastewater). Thus, for the abrasive sludge, two new mortar recipes were proposed, made by replacing fractions of sand with abrasive sludge. The series of cast samples R1 and R2 were subjected to mechanical tests and an increase in bulk density was found with the replacement of parts of the sand component with abrasive sludge, a decrease in mechanical tensile strength in bending and compression, which can be explained by the fact that wet abrasive sludge was used. Another line of research addressed the study of the possibility of reusing discharged wastewater. From this point of view, chemical analyzes were performed for two water samples on the basis of which it could be concluded that the recovered wastewater can be reused in the water supply installation of the abrasive water jet cutting machines. Based on the results obtained, it can be said that the resulting waste can be a raw material for the construction of building materials and can contribute to a considerable reduction in drinking water consumption. [ABSTRACT FROM AUTHOR]

The current context of climate change requires the efficiency of district heating systems. The article proposes the implementation of modernization solutions for district heating systems in order to reduce heat loss on the distribution system and implicitly CO2 emissions at the level of thermal agent production. The case study analyses the supply of the Forestry Technical College from Timisoara, which has a heat demand for the building of 1MW and is located at a distance of 1200m from the nearest thermal point. Simulations were performed for several efficiency stages of the central heating system, which before efficiency, operated without any control over the supply with thermal agent. The first stage of efficiency involves the transition from the uncontrolled continuous supply of the final consumer to an adjustable supply according to the thermal energy requirement, and the second stage represents the reduction of supply temperatures on the supply and return pipes from the high temperature regime (tt = 80°C and tr = 60°C), to an average temperature regime (tt = 60°C and tr = 40°C). [ABSTRACT FROM AUTHOR]

Given the current context regarding environmental pollution, in which conventional installations also participate, the aim of this article is to analyse whether photovoltaic systems are a viable solution to help solve this problem. Thus, the article analyses the way in which the electricity production of photovoltaic installations is influenced by the aging of the photovoltaic cells that make it up, but also by certain natural factors (water droplets, shading caused by clouds). Experimental measurements were performed on a new ZY-S100 thin-film photovoltaic panel and then on an aged one (7 years of operation) using an MI 3109 EurotestPV Lite METREL. When it comes to the main problem addressed in the paper, the influence of the aging of photovoltaic cells on the efficiency of the photovoltaic panels, the measurements indicated that the aged panel suffered a 25% decrease in efficiency in the seven years of operation, which comes to a decrease of 3.57% for each year. [ABSTRACT FROM AUTHOR]

Water consumption worldwide has increased considerably in recent decades and has a growing trend due to population growth in the coming years. Migration of the population from rural areas to urban areas will lead to problems arising from water insufficiency in crowded areas. Urban areas are oftentimes up to 8°F warmer than the surrounding rural area, creating “urban heat islands”. In densely populated areas where more water is consumed, an important consideration would be whether a part of the urban water requirement can be covered by rainwater harvesting. First, rainwater harvesting helps to conserve water by reducing the amount of water needed for toilet (and urinal) flushing, and outdoor watering. The article analyzes the water consumption averaged between years 2015 and 2017 (thermal power plants, humidifiers, and plumbing) for a 25- stories building located in Canada. Based on the analysis, it was found that the combined seasonal average for the spring and summer was 62% higher than the winter and fall seasons. By using rainwater instead of potable (drinking) water for these applications, homeowners can reduce their daily water use by approximately 30%. [ABSTRACT FROM AUTHOR]

In present, water save has become essential in all regions, even where water seems abundant. The most effective way to save hot water from buildings plumbing is recirculation systems, but for high rise buildings the things are more complex. The article approaches an analysis of a 27-storey high-rise building with three recirculation pumps and associated heat exchangers. The lower head zone pumps and smaller local heat exchangers are used successfully. By using a low head pump instead of a high head pump it can be saved the operating cost, even though the initial cost of a small double wall plate heat exchanger and low head pump is comparable to the cost of a high head pump. [ABSTRACT FROM AUTHOR]

In agreement with lasting development and ensuring a sustainable future for administrative territorial units (ATUs) in Romania, the article proposes measures to support the environment with positive effects on natural freshwater resources and consumption. The study presents the context, necessity, and justification for plumbing modification from buildings, focused on the reduction of drinking water consumption through the recovery, storage, and reuse of rainwaters. The analysis of climatic parameters, quality indicators of rainwater harvested, and the proposed technical solutions was performed to justify the usefulness and the necessity of implementing the solutions for recovering and reusing this resource. [ABSTRACT FROM AUTHOR]

Copyright of Romanian Journal of Civil Engineering / Revista Română de Inginerie Civilă is the property of Matrix Rom and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Romanian Journal of Civil Engineering / Revista Română de Inginerie Civilă is the property of Matrix Rom and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)