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In Poland and other countries in Central Europe, residential buildings from the second half of the 20th century dominate, which have recently undergone deep thermomodernisation. Research on the retrofitting of residential buildings has focused mainly on energy efficiency, with only a few studies on indoor air quality. The aim of this study was to present a comparative analysis of the impact of five ventilation scenarios (three natural and two mechanical) on CO2 concentration and energy demand for heating and ventilation in residential spaces of a multi-family building located in Poland. The analyses were based on the results of building performance co-simulation using the EnergyPlus and CONTAM programs carried out under dynamic conditions with a 5 min time step for the entire heating season. The calculations took into account the instantaneous occupancy variability of twenty apartments. In the buildings equipped with new tight windows, the natural ventilation system provided extremely low air exchange (on average 0.1 h−1) and poor indoor air quality (average CO2 concentration at the level of 2500 ppm). Opening windows to ventilate the rooms generated a multiple increase (up to 8 times) in heating demand during these periods, but average CO2 concentration was on the level of 930 ppm. The use of mechanical ventilation was profitable both in terms of energy savings (at the level of 50%) and improvement in the indoor air. [ABSTRACT FROM AUTHOR]

In this study, a controller method for window opening was developed to naturally ventilate a classroom with 30 occupants. The aim was to improve indoor environment quality and limit the probability of COVID infection risk simultaneously. The study was based on a building performance simulation using combined EnergyPlus, CONTAM, and Python programs. Seven cases with automatically opening windows were considered. Opening window parameters were optimized by genetic algorithms. It was shown that the optimized controller with indoor environment functions improved classroom ventilation and considerably decreased CO2 concentration compared to a reference case where the windows were opened only during breaks, and the controller also improved occupants' thermal comfort. However, there was a noticeable increase in energy demand, caused by the increased air change rate. Introducing the probability of infection risk function to the controller did not reduce the transmission risk substantially, and the probability of infection transmission was high for 80% of the classroom occupancy time. The risk of infection changed only when additional actions were taken, such as introducing face masks, indoor air cleaners, or reducing the number of students present in the classroom. In these cases, it was possible to prevent the infection transmission for more than 90% of the lecture time (R0 < 1). [ABSTRACT FROM AUTHOR]

In buildings with good-quality thermal insulation of external partitions, the main component of the building's heat balance is the heat demand for ventilation. The reduction of this energy demand cannot be achieved at the expense of thermal comfort of the occupants and indoor air quality. The aim of this article is to analyze the impact of various ventilation strategy (natural and mechanical) on heating demand, thermal comfort, and CO2 concentration in a single-family house located in Poland. The benefits of using fans integrated with the earth tube were tested. The study was based on the numerical energy simulation of a multi-zone building model for the entire calendar year. Contam, EnergyPlus, and Python programs were used to perform calculations. The thermal model was validated on the results of temperature measurements in the building. To obtain the best solutions, the parameters of the systems considered have been optimized with the use of genetic algorithms. Various optimal parameters of the earth tube (diameter, length, and foundation depth) were obtained during this research. The highest number of thermal discomfort hours was obtained in the naturally ventilated building with automatic window opening. This system supplied to the rooms a large amount of cool outdoor air in winter and warm air in summer, causing instantaneous rapid fluctuations in indoor temperature. Supplementing the mechanical ventilation control system with CO2 concentration sensors resulted in a much higher amount of ventilation air supplied to the rooms compared to systems controlled only by temperature sensors, resulting in an increase in heat demand. [ABSTRACT FROM AUTHOR]

Currently, more and more emphasis is being placed on reducing energy consumption in buildings to reduce greenhouse gases in the atmosphere. Building performance simulation is very useful to predict energy demand and indoor environment quality. An indispensable element of the simulation is the validation and calibration of the model, which is an arduous process. The aim of the study was to present a four-level validation (using measurement results) and calibration of a thermal model of a naturally ventilated single-family house. Numerical calculations using co-simulation between EnergyPlus and Contam were performed. The results of the one-year simulation measurements of the indoor temperature and ventilation airflows were compared. After the calibration was performed, a high convergence of the results was found. The normalized mean bias error for hourly and monthly values did not exceed 1% and the coefficient of variation of the root mean squared error was a maximum of 7% with a simultaneous high correlation of the results in the range from 0.85 to 0.89. It was found that the final results were significantly influenced by the appropriate modeling of air exchange in the building, including the opening of windows. [ABSTRACT FROM AUTHOR]

An inappropriate indoor climate, mostly indoor temperature, may cause occupants’ discomfort. There are a great number of air conditioning systems that make it possible to maintain the required thermal comfort. Their installation, however, involves high investment costs and high energy demand. The study analyses the possibilities of limiting too high a temperature in residential buildings using passive cooling by means of ventilation with ambient cool air. A fuzzy logic controller whose aim is to control mechanical ventilation has been proposed and optimized. In order to optimize the controller, the modified Multiobjective Evolutionary Algorithm, based on the Strength Pareto Evolutionary Algorithm, has been adopted. The optimization algorithm has been implemented in MATLAB®, which is coupled by MLE+ with EnergyPlus for performing dynamic co-simulation between the programs. The example of a single detached building shows that the occupants’ thermal comfort in a transitional climate may improve significantly owing to mechanical ventilation controlled by the suggested fuzzy logic controller. When the system is connected to the traditional cooling system, it may further bring about a decrease in cooling demand. [ABSTRACT FROM AUTHOR]

The building sector is one of the largest energy consumers in the world, comprising about 40% of the total energy consumption in numerous countries. Early design decisions have a significant impact on the energy performance of buildings. The paper presents the multi-variable optimization of the selected design parameters in a single-family building in temperate climate conditions. The influence of four types of windows, their size, building orientation, insulation of external wall, roof and ground floor and infiltration on the life cycle costs (LCC) is analyzed. Optimal selection of the design parameters is carried out using genetic algorithms by coupling the building performance simulation program EnergyPlus with optimization environment. The simulations were conducted for seven optimization cases. The analysis is performed for two variants of a building with heating and cooling systems and with a heating system only. Depending on the analyzed case, the life cycle costs decreased from 7% to 34% LCC value of the reference building. In the case of temperate climate, the building optimization (in terms of heat demand only) substantially reduces the heating costs, yet the summer thermal comfort conditions deteriorate significantly. [ABSTRACT FROM AUTHOR]

Buildings consume energy, which is a major contributor to greenhouse gas emissions. In order to reduce their environmental impact, it is important to choose suitable building materials and energy source. The paper presents the results of a multi-variant analysis of five environmental impact categories (global warming potential, acidification, eutrophication, ozone layer depletion, and total use of primary energy) for a single-family house located in Poland in a 25-year life cycle. The tests were carried out for two different types of building structures (brick and wooden), two variants of external partition insulation, and four heat sources. The following computer programs were used for the calculations: OpenStudio and EnergyPlus, and One Click LCA. The analysis took into account the erection of the building in its shell and the energy consumption for heating in a 25-year life cycle. Studies have shown that when an electric heat source is used, the use stage has the greatest environmental impact, accounting for up to 80% of the total emissions over the life cycle. This ratio can be reduced by half in the case of a house with thicker external wall insulation and an eco-biomass boiler. [ABSTRACT FROM AUTHOR]

In regions with temperate climates, the thermal insulation of buildings is increased to reduce the need for heating. It might significantly reduce human thermal comfort in the summer period. The problem can increase with global warming. The aim of the paper is to analyze the heating and cooling demand, as well as thermal comfort in a single-family house located in Poland for three climate scenarios (typical, real, and future weather data) and for two types of thermal insulation of external walls. In the study, two ways of cooling the building were taken into account: using split air conditioners and using fresh airflow provided through the opening of windows. The open area and the temperatures for opening windows have been optimized using a two-criteria function. The energy simulation was carried out in EnergyPlus 9.4 software. The multi-zone model was validated on the basis of the temperature measurement. The results showed that there will be a problem with ensuring thermal comfort in the future, especially in well-insulated buildings. The energy demand for cooling will be greater than the demand for heating. The use of passive cooling is a good solution for residential buildings in these regions, and the number of discomfort hours is small (max 5%). [ABSTRACT FROM AUTHOR]

The household sector in Poland consumes more than 25% of final energy. At the same time, residents reported dissatisfaction with the thermal conditions during the summer months. This paper details the search for passive and energy-efficient solutions to improve thermal comfort in Polish dwellings. A five-story, multi-family building was selected for this research. Analyses were conducted in apartments located on the top two floors using EnergyPlus (for thermal calculations) and CONTAM (for air exchange calculations) simulation programs for current and future climatic conditions. The stochastic behavior of people when opening windows and automatically controlled systems supplying external air to the building was considered. Airing the apartments by opening windows increased the heating demand but reduced the number of thermal discomfort hours by over 90%. The degree of airing by opening windows depends on residents opening their windows; therefore, a mechanical supply of external air controlled by both internal and external temperatures was proposed and tested. [ABSTRACT FROM AUTHOR]

Today, there is a great deal of emphasis on reducing energy use in buildings for both economic and environmental reasons. Investors strongly encourage the insulating of buildings. Buildings without cooling systems can lead to a deterioration in thermal comfort, even in transitional climate areas. In this article, the effectiveness of natural ventilation in a passive cooling building is analyzed. Two options are considered: cooling with external air supplied to the building by fans, or by opening windows (automatically or by residents). In both cases, fuzzy controllers for the cooling time and supply airflow control are proposed and optimized. The analysis refers to a typical Polish single-family building. Simulations are made with the use of the EnergyPlus program, and the model is validated based on indoor temperature measurement. The calculations were carried out for different climate data: standard and future (warmed) weather data. Research has shown that cooling with external air can effectively improve thermal comfort with a slight increase in heating demand. However, to be able to reach the potential of such a solution, fans should be used. [ABSTRACT FROM AUTHOR]

This paper presents a comparative analysis of the carbon footprint, energy demand and life cycle costs of a model of a building located in the Central Europe climate zone. One specific example—the quantitative differences in global warming potential, life cycle costs and thermal comfort—has been shown, depending on the different construction (wood, brick) and heat sources used; traditional and energy-saving solutions have been considered. The research was carried out using the EnergyPlus simulation program for a multi-zone model of a naturally ventilated single-family house. Calculations were made for a 25-year life cycle using the standard climate data for Warsaw (Poland). The real occupancy schedule of the individual rooms was adopted and the instantaneous ventilation airflow was modeled, and its intensification due to the additional opening of windows was optimized. An estimated budget of the entire structure of the building and the heat sources was used for the cost analysis. The research has succeeded in developing some general conclusions and guidelines and recommendations for both the investors and designers of energy-saving and environmentally friendly houses. Considering the most economical an ecological solution, wooden houses are better than brick houses. In the wooden building, however, there are a larger number of thermal discomfort hours. [ABSTRACT FROM AUTHOR]

In museums, poor microclimate conditions, especially large changes in relative humidity and temperature, can lead to serious deterioration of the exhibits. Properly designed heating, ventilation, and air conditioning (HVAC) systems for precise control of the air parameters are required. However, due to the financial restrictions of museums, complex air-conditioning systems are often not feasible. In this study, we tested and propose novel methods to reduce the short- and long-term fluctuations in the relative humidity in exhibition rooms of a Polish museum. The methods only include indoor temperature and ventilation airflow control strategies, without the use of (de)humidification equipment. The analysis is based on simulations using EnergyPlus software. A multi-zone thermal model of the museum building was validated and calibrated with measured data. A full calendar year was simulated for five control cases (including the current method used) and two internal heat gain schedules. The energy demand for heating and cooling for each case was calculated. The combination of temperature control and adequate ventilation using ambient airflow allows for dramatic improvement in the microclimate conditions. The proportion of the year when the instantaneous indoor relative humidity is ±5% from set point decreased from 85% to 20%. A significant effect was obtained over the summer months. [ABSTRACT FROM AUTHOR]

In this paper, we present a multi-variant analysis of the determination of the accuracy of the seasonal heat demand in buildings. The research was based on the linear regression method for data obtained during short periods of measurement. The analyses were carried out using computer simulation, and the numerical models of the multifamily building and school building were used for the simulation. The simulations were performed using the TRNSYS, ESP-r, and CONTAM programs. The multi-zone models of the buildings were validated based on the measurement data. The impact of the building's parameters (airtightness, insulation, and occupancy schedule) on the determination of the accuracy of the seasonal heat demand was analyzed. The analyses allowed guidelines to be developed for determining the seasonal energy consumption for heating and ventilation based on short periods of heat demand measurements and to determine the optimal duration of the measurement period. [ABSTRACT FROM AUTHOR]

A properly designed house should provide occupants with the high level of thermal comfort at low energy demand. On many occasions investors choose to add additional insulation to the buildings to reduce heat demand. This may lead to overheating of the building without a cooling system in summer periods (these prevail in Poland). Additionally, it affects the deterioration of thermal comfort, which can only be improved by increasing ventilation. The paper presents the multi-objective optimization of the selected design parameters in a single-family building in temperate climate conditions. The influence of four types of windows, their size, building orientation, insulation of external wall, roof and ground floor and infiltration on the life cycle costs and thermal comfort is analyzed for the building without cooling. Infiltration changes during the simulation and is controlled by a special controller. Its task is to imitate the behavior of occupants in changing the supply airflow. Optimal selection of the design parameters is carried out using Non-dominated Sorting Genetic Algorithm II (NSGA-II) by coupling the building performance simulation program EnergyPlus with optimization environment. For the single-family house, optimal values of design variables for three different criteria are presented. [ABSTRACT FROM AUTHOR]