scholarly journals Evaluation of Primary Energy from Photovoltaics for a Nearly Zero Energy Building (nZEB): A Case Study in Lithuania

Proceedings ◽  
2020 ◽  
Vol 51 (1) ◽  
pp. 5
Author(s):  
Rokas Tamašauskas ◽  
Jolanta Šadauskienė ◽  
Dorota Anna Krawczyk ◽  
Violeta Medelienė
Keyword(s):  
Energy Consumption ◽  
Primary Energy ◽  
Primary Energy Consumption ◽  
Renewable Energy Resources ◽  
Zero Energy ◽  
Energy Factor ◽  
Average Value ◽  
Pv Systems ◽  
Zero Energy Building ◽  
The Difference

The European Commission has set the target in the Energy Efficiency Directive (EED) to reduce EU primary energy consumption in 2020 by 20%. A crucial aspect of the overall assessment of energy saving measures that affect electricity demand is the primary energy factor that is used for evaluation of primary energy consumption from renewable energy resources in a Nearly Zero Energy Building (nZEB). The analysis of the resources has revealed that energy from photovoltaics is evaluated using different methods. Therefore, this article’s aim is to investigate and evaluate the primary energy factor of energy from photovoltaics using the data of produced and consumed energy of 30 photovoltaic (PV) systems operating in Lithuania. Investigation results show that the difference of non-renewable primary energy factor between the PV systems due to capacities is 35%. In addition, the results of the studies show that the average value of the primary energy factor of PV systems in Lithuania is 1.038.

scholarly journals Analysis of Primary Energy Factors from Photovoltaic Systems for a Nearly Zero Energy Building (NZEB): A Case Study in Lithuania

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4099 ◽  
Author(s):  
Rokas Tamašauskas ◽  
Jolanta Šadauskienė ◽  
Dorota Anna Krawczyk ◽  
Violeta Medelienė
Keyword(s):  
Energy Savings ◽  
Primary Energy ◽  
Photovoltaic Systems ◽  
The European Union ◽  
Zero Energy ◽  
Energy Factor ◽  
Average Value ◽  
Pv Systems ◽  
Zero Energy Building ◽  
Energy Factors

Following a new climate and energy plan, the European Union (EU) gives big attention to energy savings. The overall assessment of energy saving measures is very important. Thus, it is crucial to estimate in a proper way the primary energy factor, which is used in calculations of primary energy consumption from renewable energy (RE) sources in a Nearly Zero Energy Building (NZEB). The conduced studies of the literature and national regulations showed that different methods to determine energy from photovoltaic (PV) systems are used. The aim of this paper is to evaluate the primary energy factors of energy from photovoltaics and determine the average value. To achieve this aim, the data of 30 photovoltaic systems from Lithuania were analyzed. The results show a 35% diversification in the values of non-renewable primary energy factor, depending on the PV systems’ capacities, with the average on a level of 1.038.

scholarly journals Cost-Benefit Analysis of Hybrid Photovoltaic/Thermal Collectors in a Nearly Zero-Energy Building

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1582 ◽  
Author(s):  
Conti ◽  
Schito ◽  
Testi
Keyword(s):  
Energy Consumption ◽  
Energy Demand ◽  
Electrical Energy ◽  
Energy System ◽  
Primary Energy ◽  
Hot Water ◽  
Solar Thermal ◽  
Primary Energy Consumption ◽  
Solar Thermal Energy ◽  
Zero Energy

This paper analyzes the use of hybrid photovoltaic/thermal (PVT) collectors in nearly zero-energy buildings (NZEBs). We present a design methodology based on the dynamic simulation of the whole energy system, which includes the building energy demand, a reversible heat pump as generator, the thermal storage, the power exchange with the grid, and both thermal and electrical energy production by solar collectors. An exhaustive search of the best equipment sizing and design is performed to minimize both the total costs and the non-renewable primary energy consumption over the system lifetime. The results show that photovoltaic/thermal technology reduces the non-renewable primary energy consumption below the nearly zero-energy threshold value, assumed as 15 kWh/(m2·yr), also reducing the total costs with respect to a non-solar solution (up to 8%). As expected, several possible optimal designs exist, with an opposite trend between energy savings and total costs. In all these optimal configurations, we figure out that photovoltaic/thermal technology favors the production of electrical energy with respect to the thermal one, which mainly occurs during the summer to meet the domestic hot water requirements and lower the temperature of the collectors. Finally, we show that, for a given solar area, photovoltaic/thermal technology leads to a higher reduction of the non-renewable primary energy and to a higher production of solar thermal energy with respect to a traditional separate production employing photovoltaic (PV) modules and solar thermal (ST) collectors.

scholarly journals Evaluating Design Strategies for Nearly Zero Energy Buildings in the Middle East and North Africa Regions

Designs ◽  
2018 ◽  
Vol 2 (4) ◽  
pp. 35 ◽  
Author(s):  
Yahya Al-Saeed ◽  
Abdullahi Ahmed
Keyword(s):  
Energy Consumption ◽  
Middle East ◽  
North Africa ◽  
Building Energy ◽  
Primary Energy ◽  
Positive Energy ◽  
Primary Energy Consumption ◽  
Existing Buildings ◽  
Zero Energy ◽  
Mena Region

There is international pressure for countries to reduce greenhouse gas emissions, which are blamed as the main cause of climate change. The countries in the Middle East and North Africa (MENA) region heavily rely on fossil fuel as the main energy source for buildings. The concept of nearly zero energy buildings (nZEB) has been defined and standardized for some developed countries. While most of the developing countries located in the MENA region with hot and tropical climate lack building energy efficiency standards. With pressure to improve energy and environmental performance of buildings, nZEB buildings are expected to grow over the coming years and employing these buildings in the MENA region can reduce building energy consumption and CO2 emissions. Therefore, the paper focuses on: (a) reviewing the current established nZEB standards and definitions for countries in the hot and warm climate of Europe, (b) investigate the primary energy consumption for current existing buildings in the MENA region, and (c) establishing a standard for nZEB and positive energy buildings in kWh/m2/year for the MENA region using a building simulation platform represented using Autodesk Insight 360. The result of the simulation reveals high energy use intensity for existing buildings in the MENA region. By improving building fabric and applying solar photovoltaics (PV) in the base model, significant reductions in primary energy consumption was achieved. Further design improvements, such as increasing the airtightness and using high efficiency solar PV, also contributed to positive energy buildings that produce more energy than they consume.

Saving Primary Energy Consumption Through Exergy Analysis of Combine Distillation and Power Plant

2012 ◽  
Vol 9 (2) ◽  
pp. 65
Author(s):  
Alhassan Salami Tijani ◽  
Nazri Mohammed ◽  
Werner Witt
Keyword(s):  
Energy Consumption ◽  
Power Plant ◽  
Heat Pump ◽  
Heat Recovery ◽  
Energy Savings ◽  
Primary Energy ◽  
Heat Pumps ◽  
Saturated Steam ◽  
Distillation Unit ◽  
Primary Energy Consumption

Industrial heat pumps are heat-recovery systems that allow the temperature ofwaste-heat stream to be increased to a higher, more efficient temperature. Consequently, heat pumps can improve energy efficiency in industrial processes as well as energy savings when conventional passive-heat recovery is not possible. In this paper, possible ways of saving energy in the chemical industry are considered, the objective is to reduce the primary energy (such as coal) consumption of power plant. Particularly the thermodynamic analyses ofintegrating backpressure turbine ofa power plant with distillation units have been considered. Some practical examples such as conventional distillation unit and heat pump are used as a means of reducing primary energy consumption with tangible indications of energy savings. The heat pump distillation is operated via electrical power from the power plant. The exergy efficiency ofthe primary fuel is calculated for different operating range ofthe heat pump distillation. This is then compared with a conventional distillation unit that depends on saturated steam from a power plant as the source of energy. The results obtained show that heat pump distillation is an economic way to save energy if the temperaturedifference between the overhead and the bottom is small. Based on the result, the energy saved by the application of a heat pump distillation is improved compared to conventional distillation unit.

scholarly journals Decarbonization of Residential Building Energy Supply: Impact of Cogeneration System Performance on Energy, Environment, and Economics

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2538
Author(s):  
Praveen K. Cheekatamarla
Keyword(s):  
Carbon Dioxide ◽  
Power Generation ◽  
Energy Consumption ◽  
Carbon Footprint ◽  
Residential Buildings ◽  
Building Energy ◽  
Primary Energy ◽  
Primary Energy Consumption ◽  
Cogeneration System ◽  
The Impact

Electrical and thermal loads of residential buildings present a unique opportunity for onsite power generation, and concomitant thermal energy generation, storage, and utilization, to decrease primary energy consumption and carbon dioxide intensity. This approach also improves resiliency and ability to address peak load burden effectively. Demand response programs and grid-interactive buildings are also essential to meet the energy needs of the 21st century while addressing climate impact. Given the significance of the scale of building energy consumption, this study investigates how cogeneration systems influence the primary energy consumption and carbon footprint in residential buildings. The impact of onsite power generation capacity, its electrical and thermal efficiency, and its cost, on total primary energy consumption, equivalent carbon dioxide emissions, operating expenditure, and, most importantly, thermal and electrical energy balance, is presented. The conditions at which a cogeneration approach loses its advantage as an energy efficient residential resource are identified as a function of electrical grid’s carbon footprint and primary energy efficiency. Compared to a heat pump heating system with a coefficient of performance (COP) of three, a 0.5 kW cogeneration system with 40% electrical efficiency is shown to lose its environmental benefit if the electrical grid’s carbon dioxide intensity falls below 0.4 kg CO2 per kWh electricity.

scholarly journals Assessment Methodology for Efficiency, CO2-Emissions and Primary Energy Consumption for Refrigeration Technologies in the Industry

2018 ◽  
Vol 882 ◽  
pp. 215-220
Author(s):  
Matthias Koppmann ◽  
Raphael Lechner ◽  
Tom Goßner ◽  
Markus Brautsch
Keyword(s):  
Energy Consumption ◽  
Energy Efficient ◽  
Air Conditioning ◽  
Primary Energy ◽  
Primary Energy Consumption ◽  
Assessment Methodology ◽  
Alternative Technologies ◽  
Overall Efficiency ◽  
Chp System ◽  
The Individual

Process cooling and air conditioning are becoming increasingly important in the industry. Refrigeration is still mostly accomplished with compression chillers, although alternative technologies are available on the market that can be more efficient for specific applications. Within the scope of the project “EffiCool” a technology toolbox is currently being developed, which is intended to assist industrials users in selecting energy efficient and eco-friendly cooling solutions. In order to assess different refrigeration options a consistent methodology was developed. The refrigeration technologies are assessed regarding their efficiency, CO2-emissions and primary energy consumption. For CCHP systems an exergetic allocation method was implemented. Two scenarios with A) a compression chiller and B) an absorption chiller coupled to a natural gas CHP system were calculated exemplarily, showing a greater overall efficiency for the CCHP system, although the individual COP of the chiller is considerably lower.

Performance analysis of a combined cooling, heating, and power system driven by a waste biomass fired Stirling engine

2010 ◽  
Vol 225 (2) ◽  
pp. 420-428 ◽  
Author(s):  
J Harrod ◽  
P J Mago
Keyword(s):  
Energy Consumption ◽  
Natural Gas ◽  
Wood Chip ◽  
Primary Energy ◽  
Stirling Engine ◽  
Primary Energy Consumption ◽  
Operational Cost ◽  
Excess Production ◽  
Prime Movers ◽  
Combined Cooling

Due to the soaring costs and demand of energy in recent years, combined cooling, heating, and power (CCHP) systems have arisen as an alternative to conventional power generation based on their potential to provide reductions in cost, primary energy consumption, and emissions. However, the application of these systems is commonly limited to internal combustion engine prime movers that use natural gas as the primary fuel source. Investigation of more efficient prime movers and renewable fuel applications is an integral part of improving CCHP technology. Therefore, the objective of this study is to analyse the performance of a CCHP system driven by a biomass fired Stirling engine. The study is carried out by considering an hour-by-hour CCHP simulation for a small office building located in Atlanta, Georgia. The hourly thermal and electrical demands for the building were obtained using the EnergyPlus software. Results for burning waste wood chip biomass are compared to results obtained burning natural gas to illustrate the effects of fuel choice and prime mover power output on the overall CCHP system performance. Based on the specified utility rates and including excess production buyback, the results suggest that fuel prices of less than $23/MWh must be maintained for savings in cost compared to the conventional case. In addition, the performance of the CCHP system using the Stirling engine is compared with the conventional system performance. This comparison is based on operational cost and primary energy consumption. When electricity can be sold back to the grid, results indicate that a wood chip fired system yields a potential cost savings of up to 50 per cent and a 20 per cent increase in primary energy consumption as compared with the conventional system. On the other hand, a natural gas fired system is shown to be ineffective for cost and primary energy consumption savings with increases of up to 85 per cent and 24 per cent compared to the conventional case, respectively. The variations in the operational cost and primary energy consumption are also shown to be sensitive to the electricity excess production and buyback rate.

scholarly journals Optimization of Performance Parameter Design and Energy Use Prediction for Nearly Zero Energy Buildings

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3252 ◽  
Author(s):  
Xiaolong Xu ◽  
Guohui Feng ◽  
Dandan Chi ◽  
Ming Liu ◽  
Baoyue Dou
Keyword(s):  
Energy Consumption ◽  
Energy Saving ◽  
Energy Demand ◽  
Maximum Relative Error ◽  
Performance Parameters ◽  
Zero Energy ◽  
Saving Ratio ◽  
Zero Energy Building ◽  
Artificial Neural ◽  
Zero Energy Buildings

Optimizing key parameters with energy consumption as the control target can minimize the heating and cooling needs of buildings. In this paper we focus on the optimization of performance parameters design and the prediction of energy consumption for nearly Zero Energy Buildings (nZEB). The optimal combination of various performance parameters and the Energy Saving Ratio (ESR)are studied by using a large volume of simulation data. Artificial neural networks (ANNs) are applied for the prediction of annual electrical energy consumption in a nearly Zero Energy Building designs located in Shenyang (China). The data of the energy demand for our test is obtained by using building simulation techniques. The results demonstrate that the heating energy demand for our test nearly Zero Energy Building is 17.42 KW·h/(m2·a). The Energy Saving Ratio of window-to-wall ratios optimization is the most obvious, followed by thermal performance parameters of the window, and finally the insulation thickness. The maximum relative error of building energy consumption prediction is 6.46% when using the artificial neural network model to predict energy consumption. The establishment of this prediction method enables architects to easily and accurately obtain the energy consumption of buildings during the design phase.

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