Polish Climatic Conditions Research Articles

Development and tests of the novel configuration of the solar chimney with sensible heat storage

Heating, ventilation, and air conditioning systems account for a significant part of the energy usage in buildings and are primarily responsible for greenhouse gas emissions and operating costs. These can be lowered by the adoption of solar energy. This paper presents the developing and testing of a novel solar chimney with sensible heat storage. The thermal performance and potential contribution of the developed thermal chimney to decreasing residential buildings energy consumption in Polish climate conditions is investigated. The developed solar air chimney is composed of a novel accumulation material that allows for sensible heat storage. Solar radiation can heat the accumulation layer during the day and the stored energy can be used to preheat the ventilation air. The prototype of the solar chimney was tested in laboratory conditions using a dedicated experimental rig. Furthermore, numerical calculations were performed using TRNSYS software, where a validated dynamic numerical model was developed to simulate the performance of the device. The results show that airflow direction, volume, and the number of heated walls significantly impact the power transferred from the solar chimney walls to the air. The maximum power transferred from the solar chimney walls to the air per unit of surface varied from 360.2 W/m2 (when all walls were heated) to 672.4 W/m2 (when only one wall was heated). The validated model underestimates the outlet air temperature of the solar chimney by a maximum of 0.39 °C on average basis and shows that the increase of air temperature between −10 and 20 °C at 1000 W/m2 determines a decrease of 12.5 % of the thermal output. The obtained results allow one to highlight that the proposed solution can be considered as a replacement for typical brick chimneys located on roofs or as a thermal storage wall.

Storing Electric Energy Generated by a Photovoltaic Installation to Increase Profit from Its Sale—Case Study in Poland

Battery systems enable the sustainable use of energy from renewable energy installations that are characterized by variable time availability. The present study investigated the benefits of implementing an electrical energy storage system to a photovoltaic (PV) installation in the Polish climatic conditions. The impact of such a system on increasing profits from energy sales was verified. The use of storage allows for shifting the process of feeding energy into the grid to later hours when it is more expensive. The production volume and timing of energy generation were considered using the example of a 5 kWp research installation located in the Laboratory of Renewable Energy. The yields and energy prices were analyzed on an hourly basis for the year 2023. The considered system is additionally equipped with a battery with a capacity of 15 kWh. Analyses have shown that this system covers 55.6% of days in a year where the entire daily production from the PV installation can be stored. Additionally, the feasibility of using different energy storage capacities to shift the sale of the maximum energy volume was examined. Also the payback period of investments was considered for four scenarios (from the most expensive devices to the cheapest ones with subsidies). Prices were compared with profits resulting from the use of storage systems of a given capacity, as well as with the lengths of warranties covering the devices.

Development of the Polish Power Sector towards Energy Neutrality—The Scenario Approach

This article discusses three scenarios for the transformation of the Polish power system leading to the achievement of climate neutrality through investment in renewable energy sources. The scenarios differ in terms of the role played by the selected energy technologies. The scenarios were developed using the balancing tool, the Simulator Polish Power System, which analyzed the development of the national power system in terms of optimal costs of achieving climate neutrality and the lowest possible price of electricity generation. The research shows that under Polish climatic conditions, 100% RES energy can be achieved in the balance, but ensuring the continuity of energy supply, which in future will be generated mainly from this type of source, requires the participation of controllable sources such as gas-fired power plants powered by biomethane and energy storage facilities. The scenarios assume balancing RES sources with 15–25 GW of available gas sources and 40 GWh in electricity storage. The article also discusses factors limiting the suggested scenarios, such as the availability of sustainable biomethane in Poland or limitations associated with the possibility of building onshore and offshore wind turbines.

Analysis of the Energy, Environmental and Economic Efficiency of Multi-Family Residential Buildings in Poland

Improving the energy efficiency of buildings is one of the main challenges facing Europe in the context of climate neutrality policy. In this article, the authors decided to investigate the impact of thermal insulation of building envelopes and the type of ventilation on the energy efficiency of multi-family buildings located in different Polish cities. In accordance with EU directives, economic analyses of the costs incurred during the lifecycle and calculations of CO2 emissions were carried out for the analyzed facilities. It was determined what measures need to be taken under Polish climatic conditions in order to meet the requirements for improving the energy efficiency of multi-family buildings. The multi-criteria analyses presented in this article provide a voice in the discussion of the issues related to the achievement of the energy performance of buildings with almost zero primary energy demand (nZEB). Based on the conclusions of the research conducted, it was possible to develop general recommendations for investors and designers of multi-family residential buildings characterized by energy efficiency and reduced environmental impact.

The selection of an electric vehicle for the existing photovoltaic system - case study in Polish climatic conditions

The article presents an algorithm for selecting an electric vehicle for your photovoltaic system. Generating electricity by distributed photovoltaic systems is a very visible trend across Europe. Individual and institutional owners are looking for opportunities to save large amounts of money spent on the purchase of electricity. Many times they have built a photovoltaic system larger than their current energy needs. The author suggests a solution to increase the energy produced for own needs instead of giving it to the power grid at unfavorable prices. Such a solution is the purchase of an electric vehicle that will be charged with surplus energy. Research on the selection of a vehicle for a photovoltaic system should start with a precise profile of the current energy consumption from the power grid, energy production from the photovoltaic system and transferring its excess to the power grid. The next step is to characterize the potential electric vehicle. Such characteristics include determination of the energy capacity of the traction battery and the methods of its charging. The final stage is the analytical confirmation of the choice made. For this purpose, the Metalog family of distributions was used to determine the probability of generating the appropriate hourly amount of energy needed to charge an electric vehicle.

Simulation and Performance Analysis of an Air-Source Heat Pump and Photovoltaic Panels Integrated with Service Building in Different Climate Zones of Poland

In recent years, due to the global energy crisis, the idea of a photovoltaic-assisted air-source heat pump (PV-ASHP) has become increasingly popular. This study provides a simulation in TRNSYS and the analysis of the use of a PV-ASHP system in a service building in different climate zones of Poland. For each of the six cities—Kolobrzeg, Poznan, Krakow, Warsaw, Mikolajki, and Suwalki, the effect of changing five system parameters (area, efficiency, type, and location of photovoltaic panels, and the use of a heat pump control strategy) on the amount of energy generated and consumed was determined. We also estimated the extent to which the photovoltaic panels could cover the energy requirements for the heat pump (HP) operation and the system could provide thermal comfort in the service room. Finally, a simplified analysis of the operating costs and capital expenditures was made. The results highlighted the issue of the incoherence of renewable energy sources and the need to store surplus energy under Polish climatic conditions. Abandoning the HP control strategy increased energy consumption by 36–62%, depending on the location and Variant, while the change in the place of the PV panels on the roof slope reduced energy generation by 16–22%. When applied to an ASHP in a service building, the use of PV panels to power it seems to be cost-effective.

Is the Polish Solar-to-Hydrogen Pathway Green? A Carbon Footprint of AEM Electrolysis Hydrogen Based on an LCA

Efforts to direct the economies of many countries towards low-carbon economies are being made in order to reduce their impact on global climate change. Within this process, replacing fossil fuels with hydrogen will play an important role in the sectors where electrification is difficult or technically and economically ineffective. Hydrogen may also play a critical role in renewable energy storage processes. Thus, the global hydrogen demand is expected to rise more than five times by 2050, while in the European Union, a seven-fold rise in this field is expected. Apart from many technical and legislative barriers, the environmental impact of hydrogen production is a key issue, especially in the case of new and developing technologies. Focusing on the various pathways of hydrogen production, the essential problem is to evaluate the related emissions through GHG accounting, considering the life cycle of a plant in order to compare the technologies effectively. Anion exchange membrane (AEM) electrolysis is one of the newest technologies in this field, with no LCA studies covering its full operation. Thus, this study is focused on a calculation of the carbon footprint and economic indicators of a green hydrogen plant on the basis of a life cycle assessment, including the concept of a solar-to-hydrogen plant with AEM electrolyzers operating under Polish climate conditions. The authors set the range of the GWP indicators as 2.73–4.34 kgCO2eq for a plant using AEM electrolysis, which confirmed the relatively low emissivity of hydrogen from solar energy, also in relation to this innovative technology. The economic profitability of the investment depends on external subsidies, because, as developing technology, the AEM electrolysis of green hydrogen from photovoltaics is still uncompetitive in terms of its cost without this type of support.

Experimental verification of the effect of air pre-cooling in dew point evaporative cooler on the performance of a solid desiccant dehumidifier

One of the research gaps regarding sorption systems to be used in air conditioning, is to increase their efficiency measured by the coefficient of performance (COP). This paper verifies experimentally the way to increase desiccant system performance, through the air pre-cooling in dew point evaporative cooler (DPIEC), before its dehumidification in a rotor desiccant. Experimental tests were carried out in a system consisting of a dew point evaporative cooler, a desiccant rotor, a heat source, and auxiliary equipment enabling the system to operate. The air humidity ratio decrease was determined during the summer by analyzing two operation configurations, both for Polish climatic conditions. In the first Configuration I, the outdoor air is dehumidified in the desiccant rotor, while in the second Configuration II, the outdoor air is pre-cooled in the dew point evaporative cooler before being directed to the rotor desiccant. Tests showed that the system operating Configuration II allows to obtain higher air dehumidification (from 1.4 times to 1.9 times depending on outdoor and regenerative air parameters). To establish system COP the results were supplemented with numerical calculations. It was found that the proposed pre-cooling allows to lower regeneration temperature to achieve the same dehumidification rate the regeneration temperature is decreased by 15°C. Consequently, the use of air pre-cooling as part of sorption air-conditioning system makes it possible to increase its energy efficiency.

Potential of CO2 Emission Reduction via Application of Geothermal Heat Exchanger and Passive Cooling in Residential Sector under Polish Climatic Conditions

The article summarizes the results of the 25-year time horizon performance analysis of the ground source heat pump that serves as a heat source in a detached house in the climatic conditions that prevail in Wrocław, Poland. The main aim is to assess the potential of ground regeneration and reduction of CO2 emission by passive cooling application. The study adds value to similar research conducted worldwide for various conditions. The behavior of the lower source of the heat pump was simulated using EED software. The ground and borehole properties, heat pump characteristics, heating and cooling load, as well as the energy demand for domestic hot water preparation have been used as input data. Based on the brine temperatures for all analyzed cases including the ground with lower and higher values of conductivity and heat capacity, the borehole filler of inferior and superior thermal properties, and the passive cooling option turned on and off, the seasonal efficiencies of the heat pump have been calculated. The energy and emission savings calculations are based on the values obtained. The application of passive cooling reduces the brine temperature drop by 0.5 K to over 1.0 K in consecutive years in the analyzed cases and the thermal imbalance by 65.0% to 65.9%. Electric energy savings for heating and domestic hot water preparation reach 4.5%, but the greatest advantage of the system is the possibility of almost emission-free colling the living spaces which allows reducing around 33.7 GWh of electric energy and 1186–1830 kg of CO2 emission for cooling.

Cumulative Energy Demand and Carbon Footprint of the Greenhouse Cultivation System

The paper describes the influence of horticultural production in greenhouses under Polish climate conditions on energy consumption, contributing to greenhouse gas emissions and global warming. Four scenarios were studied, two of which were non-renewable fuels: coal and natural gas, while the other two were renewable energy sources: wood pellets and wood chips, to identify opportunities for reducing energy costs and greenhouse gas emissions. Cumulative energy demand was defined to assess these four scenarios. The environmental impact was determined using the carbon footprint of the principal greenhouse gases emitted and using CO2 as the reference gas (CO2-equivalents). Renewable energy sources in greenhouse production can reduce the cumulative energy demand by 83.3% and greenhouse gas emissions by 95% compared to the coal-burning scenario. The presented research results relate to a greenhouse intended for growing flowers in pots, which has not been conducted so far. The article also updates the data on the environmental impact of crops grown in greenhouses located in Poland. The study provides important information for horticultural producers, mainly due to increasing competition and consumer awareness of the origin of products. Renewable energy sources in horticulture reveal a great potential in the reduction in greenhouse gases, and thus may become an inspiration to look for new solutions in this area.

Analysis of the All-Year Operation of the Solar Chimney in Polish Climatic Conditions

This work presents an analysis of the all-year operation of the solar chimney. The analyzed system consists of a rectangular solar collector located on the southern side of the solar chimney. The surface of the solar collector is 30 m2, while the chimney is 50 m in height. Hourly changes in solar radiation were taken into account in the calculations. The simulation was made for the climatic conditions in Katowice, Poland. This study takes into account the most important parameters of the power plant, such as air temperature, air velocity and power of the installation throughout the year of the power plant’s operation. The cumulative amount of electricity that is generated in each month of the year is shown. The analyzed solar power plant produces the largest amount of electricity in the second quarter of the year and the lowest in the fourth quarter, with the maximum amount of energy produced in May and the minimum in December.

Thermal Network Model for an Assessment of Summer Indoor Comfort in a Naturally Ventilated Residential Building

Costs of cooling installations cause them to be very rarely used in residential buildings in countries located in heating-dominated climates, like Poland. Hence, there arises the need to assess indoor thermal comfort during summer and to indicate ways to reduce possible overheating. This paper presents an attempt to use the thermal network model of the building zone of EN ISO 13790 to assess indoor operative temperature during four warm months from June to September. The model of the naturally ventilated single-family residential building located in central Poland was used. Performed calculations for the base case resulted in 38 and 63 days within the comfort zone at 80% acceptance level in a total of 122 days in the analyzed period for EN 15251 and ASHRAE standards, respectively. Use of external shading on windows and the roof with lower solar absorptance resulted in 46 and 70 days with acceptable conditions, respectively. Further application of night ventilation resulted in the 38 and 63 days, respectively. From the considered solutions in Polish climate conditions, windows shading seems to be the most efficient solution when controlling indoor comfort in residential buildings with no cooling system. A comparison of hourly operative temperature from that model with the detailed simulation in EnergyPlus showed a strong correlation with R2 = 0.934.

Risk of interstitial condensation in outer walls made of hemp-lime composite in Polish climatic conditions

Risk of interstitial condensation in outer walls made of hemp-lime composite in Polish climatic conditions

Design of Passive Building Foundations in the Polish Climatic Conditions

A Passive House (PH) system is not only an opportunity but also a necessity for the further development of sustainable eco-buildings. Construction of the foundation in energy-efficient houses is the key to maintaining low energy losses. The appropriate selection of building materials requires considering the thermal conditions of the environment, including its location and the zero isotherms in the ground. The main objective of this work is to analyze the possibilities of designing foundations for PHs in Poland, according to the current methodological data. In order to realize the basic aims, the work was divided into the following materials and methods: (I) literature review; (II) database of PH in Central Europe; (III) method of depth of ground freezing determination; (IV) selection of the joint of slab-on-ground foundation and external wall to analysis; (V) description and validation of the heat-transfer model. The result of the research work is: (i) analysis of the foundation under the conditions of freezing of the ground in Poland; (ii) description and validation of the heat-transfer model. The research has revealed that in the Polish climate zone, the most efficient solution for passive buildings is to build them on a foundation slab. The foundation of a building below the latest specified ground frost depths in Poland is inefficient in terms of, for example, thermal insulation, economics, and the idea of PH.

Analysis of seasonal energy consumption during drying of highly saturated moist masonry walls in polish climatic conditions

An impact of various levels of ambient air temperature and moisture content on a masonry wall drying process by applying the thermo-injection method was examined by applying numerical modeling. The new non-equilibrium model of heat and moisture transfer, developed and verified in the previous study, was used to carry out numerical experiments. One week of drying process was simulated. Drying air parameters, i.e., different relative humidities typical for four seasons in Poland (i.e., in the range of 70–90%) as well as its five different temperature levels (i.e., 20, 30, 40, 50 and 60°C) were analyzed. The key parameters monitored were the energy consumption required for the drying of building material as well as energy efficiency and entropy generated in the process. They were expressed as a function of water mass fraction in the wall to compare different parameters of the drying process. The obtained results indicated significant dependence of energy consumption in the process on parameters of drying air, i.e., temperature and humidity ratio. Higher temperatures and lower humidities levels allowed to reach lower final moisture content in the wall. But, during the first drying period, i.e., first 24 h, drying rates were found much higher than later and weakly dependent on the air temperature. The drying process was efficient even though low air temperature was used. But later higher air temperatures were required for efficient moisture removal from the wall. This observation suggests applying various drying air temperatures which in turn may allow for reduction of energy consumptions during drying of masonry walls.

Effects of Neglecting PCM Hysteresis While Making Simulation Calculations of a Building Located in Polish Climatic Conditions

The use of phase change materials (PCM) in different building applications is a hot topic in today’s research and development activities. Numerous experimental tests confirmed that the hysteresis of the phase change process has a noticeable effect on heat accumulation in PCM. The authors are trying to answer the question of whether the neglecting of hysteresis or the impact of the speed of phase transformation processes reduce the accuracy of the simulation. The analysis was performed for a model building, created to validate the energy calculations. It was also important to conduct simulations for the polish climatic conditions. The calculations were conducted for three variants of materials. In addition, in the case of models containing layers with PCM, calculations were made both taking into account, as well as excluding material hysteresis in the calculations. In the analyzed examples, after taking into account hysteresis in the calculations, the period of time when surface temperature is below the phase change temperature of the materials decreased by 10.6% and 29.4% between 01 June to 30 September, for the options with PCM boards and Dupont boards, respectively. Significant differences in surface temperature were also observed. The effects of neglecting, even relatively small hysteresis, in the calculations are noticeable and can lead to significant errors in the calculation.

Rooftop Low Angle Tilted Photovoltaic Installation under Polish Climatic Conditions

Rooftop Low Angle Tilted Photovoltaic Installation under Polish Climatic Conditions

Influence of Selected Working Conditions on Electricity Generation in Bifacial Photovoltaic Modules in Polish Climatic Conditions

This paper discusses the conversion of solar irradiance energy into electricity. Double-sided (bifacial) panels are gaining increasing popularity in commercial applications due to the increased energy yield with a constant occupied mounting surface. However, the value of the additional energy yield produced by the back of the panel depends on several important factors. This paper presents the influence of working conditions on electricity generation in bifacial modules. This paper also investigates the influence of weather conditions, the module inclination angle, and the substrate beneath the panel surface on electricity generation. Fill factor and efficiency were calculated for each case included in the study scope. Based on the current voltage, power characteristics, and calculations, the module operation for different conditions was compared. It was observed that the optimal inclination angle to the surface is higher for the bifacial modules compared to the unilateral modules. The type of surface under the module has also been indicated to impact the amount of electricity generated. The additional energy yield associated with the panels’ rear side accounts for 2% to more than 35% of the total power generated by a photovoltaic (PV) module. The unit cost of electricity generation in the analyzed cases was also determined.

Modelling of Solar Irradiance Incident on Building Envelopes in Polish Climatic Conditions: The Impact on Energy Performance Indicators of Residential Buildings

In this study, we use the data of Polish typical meteorological years and 15 transposition models to obtain global solar irradiance on sloped surfaces to calculate solar irradiance on external building partitions, solar gains, heating demands, and primary nonrenewable energy for heating and domestic hot water (EPH+W) of two typical Polish residential buildings, each for two variants in five locations. In relation to TMYs, annual solar gains were lower by −31% and −36% on average in a single and multifamily building, respectively, and the annual heating demands increased by 9% and 16%, respectively. Consequently, averaged EPH+W in relation to TMYs rose by 1.4 kWh/m2 and 4.5 kWh/m2, respectively. The mean differences between TMYs and the new method from the recently published EN-ISO 52010 standard for test Building 1 were 1.6 and 1.2 kWh/m2, for Variants 1 and 2, respectively. Similarly, for test Building 2, the mean differences were 5.1 kWh/m2 and 3.9 kWh/m2, respectively. This means that the simulation model that is chosen has a visible impact on a building’s energy performance indicators and its rating without any changes in the physical structure and use of the building.

Solar Tracking System with New Hybrid Control in Energy Production Optimization from Photovoltaic Conversion for Polish Climatic Conditions

This paper presents a comparison of the 24-month production of electricity and momentary power by two photovoltaic systems with a nominal power of 1000 Wp each. The analyzed systems are connected to the power grid and operate independently: a fixed system with optimal all-year-round angular positioning and an astronomical-sensor-controlled dual-axis tracking system. The systems under consideration consist of PV modules with a unit electrical power of 200 Wp, and the production technology of those modules is the same. The tested systems were located on the building rooftop of the Faculty of Control, Robotics and Electrical Engineering of the Poznan University of Technology in Poland (Central Poland, 52°24.4152′ N, 16°55.7958′ E) at a height of 30 m above ground level. The measurements take into account the consumption of electricity by the actuators of the dual-axis positioning system. Increases in the produced electricity by 35.6% and 44.7% were observed for local climatic conditions during the first and second measuring years, respectively, when comparing the use of the dual-axis tracking system with the use of fixed units. Results show that the analyzed region of central Poland, represented by the city of Poznań, creates favorable climatic conditions for the use of astronomical-sensor spatial positioning systems for photovoltaic modules, also in the case of a significant share of diffuse solar radiation in the global value. These results may make the planning of solar tracking investments easier and help with the estimate calculations of the total investment return period and operational costs.