The increase in greenhouse gases makes it necessary to utilize renewable energy sources such as solar energy. The most important component of any solar system is solar collector. Among various types of solar collectors, evacuated tube solar collector (ETC) has attracted many attentions especially for the application in solar water heating systems (SWHs). However, due to the intermittency in solar intensity, the ETCs may not work at their maximum functionality. In this study, the computational fluid dynamics (CFD) modeling of a heat pipe ETC (HPETC) with and without the integration of phase change materials (PCMs) is performed. In order to cross-validate the obtained results from CFD and recent experimental analysis, the boundary conditions are set as the field-testing data. In phase-I, the 3D model of commercially available HPETC is simulated, while in phase-II, the HPETC integrated with the PCM is developed. The selected type of PCM is Tritriacontane paraffin (C33H68) with melting point of 72∘C. The simulation results show an acceptable agreement with the experimental data with an average deviation of 4.80% and 2.04% for phase-I and phase-II, respectively. The result from this study can be a benchmark for further optimization of HPETCs in thermal energy storage systems.

CFD modeling of a thermal energy storage based heat pipe evacuated tube solar collector

Comparative analysis on similarities and differences of hydrogen energy development in the World's top 4 largest economies: A novel framework

A comprehensive review analysis on advances of evacuated tube solar collector using nanofluids and PCM

4E analyses and multi-objective optimization of a solar-based combined cooling, heating, and power system for residential applications

Theoretical and experimental study for temperature distribution and flow profile in all water evacuated tube solar collector considering solar radiation boundary condition

The several government subsidies available in Poland contributed to an increased interest in PV installations. Installed PV capacity increased from 100 MW in 2016 up to 2682.7 MW in July 2020. In 2019 alone, 104,000 microinstallations (up to 50 kWp) were installed in Poland. The paper determines the energy gain and the associated reduction of CO2 emissions for two types of solar installation located in Poland. The monofacial solar modules with a power of 5.04 kWp (located in Leki) and bifacial solar modules with a power of 6.1 kWp (located in Bydgoszcz). Both installations use mono-crystalline Si-based 1st generation PV cells. With comparable insolation, a bifacial installation produces approx. 10% (for high insolation) to 28% (for low insolation) more energy than a monofacial PV installation. Avoided annual CO2 emission in relation to the installation capacity ranges from 0.58 to 0.64 Mg/kWp for monofacial and from 0.68 to 0.74 Mg/kWp for bifacial and is on average approx. 16% higher for bifacial installations. Cost-benefit analyses were made. For different electricity prices, the NPV for monofacial and bifacial was determined.

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Monofacial and bifacial micro PV installation as element of energy transition-the case of Poland

In Poland, various solar collector systems are used; among them, the most popular are flat plate collectors (FPCs) and evacuated tube collectors (ETCs). The work presents two installations located at a distance of 80 km apart, working in similar external conditions. One of them contains 120 flat plate collectors and works for the preparation of hot water in a swimming pool building; the second one consists of 32 evacuated tube collectors with a heat pipe and supports the preparation of domestic hot water for a multi-family house. During the comparison of the two quite large solar installations, it was confirmed that the use of evacuated tube solar collectors shows a much better solar energy productivity than flat plate collectors for the absorber area. Higher heat solar gains (by 7.9%) were also observed in the case of the gross collector area. The advantages of evacuated tube collectors are observed mainly during colder periods, which allows for a steadier thermal energy production.

https://www.mdpi.com/1996-1073/13/7/1829/pdf

The Comparison of Solar Energy Gaining Effectiveness between Flat Plate Collectors and Evacuated Tube Collectors with Heat Pipe: Case Study

There are a lot of studies that show the legitimacy of subsidizing renewable energy; however, some mechanisms are defective, and there are problems with the appropriate allocation of funds. Therefore, this paper aims to look at the situation of allocating funds to photovoltaics (PV) micro-installations in Poland through the “My Electricity” program. The article presents the results of analyses aimed at identifying inequalities between provinces in the use of funds available under the “My Electricity” program and verifying whether these inequalities are getting worse and whether the intensity of support should not be territorially conditioned in terms of maximization an electricity production. As part of two editions of the “My Electricity” program (until 1 August 2020), over 64,000 PV micro-installations were created with an average power of approximately 5.7 kWp. The total installed PV capacity was 367.1 MWp (1st edition: 159.3 MWp, 2nd edition: 207.8 MWp). Financial resources (as a whole), in the second edition of “My Electricity” program, were distributed better than in the first edition. In the first edition, as much as 7.60% of funds were allocated inefficiently; in the second edition, it was only 3.88%. Allocation surpluses occur in provinces where the average disposable income is low and where there are a small number of households. There is a potential to introduce a territorial project selection criteria. The analysis shows that the criteria should promote provinces with higher disposable income and a larger number of households.

https://www.mdpi.com/1996-1073/14/1/231/pdf

“My Electricity” Program Effectiveness Supporting the Development of PV Installation in Poland

For the Ukrainian population, there are factors surrounding the choices and preferences one must consider when changing permanent residence. Smart residential areas should be built according to Ukrainian legislation and global innovations, which would reduce administrative dislocations, the load on megalopolises, and negative anthropogenic impacts, and should be based on the increase in energy efficiency and reducing waste. We analyzed the core principles of designing smart residential areas and concluded that constructing cutting-edge residential areas should involve private investments in order to avoid shadow schemes and irrational use of funds (in the Ukraine, the share of the shadow market is more than 50%). Research shows that, as humans inhabit a three-dimensional space, it is possible to predict migration and other permanent residence/behavioral responses, the analysis of which allows controlling migration flows and improves the conditions of Ukraine’s small residential areas based on decarbonization. We conclude that energy saving systems can reduce consumption in a city by 60% and improve Ukraine’s ecosystem. Research also shows that reducing “dislocation”, in terms of population density, by creating open, innovative, eco-friendly environments based on green economy principles, can provide innovative development maps and economic, social, and cultural population growth, decreasing the load on big cities/regional economies, and encourage the restoration of sales markets and production after the COVID-19 pandemic. We developed a model to assess the innovativeness of residential areas, apply alternative methods of energy generation, and analyze the impact of the energy production and consumption market in Europe (with recommendations for the Ukraine). This article estimates energy intensity indicators of the gross domestic product in the Ukraine and in Europe, offering methods to decrease energy dependence and increase energy efficiency in the Ukraine, by adopting alternative energy sources (e.g., biohydrogen out of residues, air, and solar energy), and enhancing environmental legislation.

Ecosystem of Environmentally Sustainable Municipal Infrastructure in Ukraine

This article attempts to model interdependencies between socio-economic, energy, and environmental factors with selected data characterizing the development of the hydrogen economy. The study applies Spearman’s correlation and a linear regression model to estimate the influence of gross domestic product, population, final energy consumption, renewable energy, and CO2 emission on chosen hydrogen indicators—production, patents, energy technology research, development, and demonstration budgets. The study was conducted in nine countries selected for their actions towards a hydrogen economy based on analyses of national strategies, policies, research and development programs, and roadmaps. The results confirm the statistically significant impact of the chosen indicators, which are the drivers for the development of the hydrogen economy from 2008 to 2018. Moreover, the empirical results show that different characteristics in each country contribute to the development of the hydrogen economy vision.

Piotr Olczak

Papers

Monofacial and bifacial micro PV installation as element of energy transition-the case of Poland

The Comparison of Solar Energy Gaining Effectiveness between Flat Plate Collectors and Evacuated Tube Collectors with Heat Pipe: Case Study

“My Electricity” Program Effectiveness Supporting the Development of PV Installation in Poland

Ecosystem of Environmentally Sustainable Municipal Infrastructure in Ukraine

The Impact of Economic, Energy, and Environmental Factors on the Development of the Hydrogen Economy