The article discusses issues related to improving the energy efficiency of heat supply systems. It draws attention to the need to take action not only for large objects and systems, but also for individual buildings and their boiler plants. Heat supply system monitoring allows for the diagnosis of the weakest elements and making decisions leading to the improvement of energy efficiency. In the case of the boiler room where the research was carried out, the results of such monitoring convinced to equip boilers with an additional automatic control system, with an algorithm limiting the number of burner switching cycles and shutdowns. Limiting the number of switching on the burners, as in the case of other combustion and electric devices, has a significant impact on the energy efficiency of the entire system. In addition, it also increases the durability of the devices, and thus reduces costs of servicing and repairs. The simplest control algorithms, often used in controllers installed in the boiler units, do not provide optimization in this respect. The external device used has allowed the number of burners on and off cycles to be limited while maintaining the quality of the heat supply to the heating installation and the heat treatment system.

The material also presents other ways to improve the energy efficiency of the heat supply system in existing multi-family buildings.

The paper presents selected issues related to the development of international coal markets. World consumption of coal dropped for the second year in a row in 2016, primarily due to lower demand from China and the U S. The share of coal in global primary energy consumption decreased to 28%. World coal production accounted to 3.66 billion toe and it was lower by 6.2% when compared to the previous year. More than 60% of this decline took place in China. The decline in global production was more than four times higher than the decrease in consumption. The sufficiency of world resources of coal are estimated at 153 years – that is three times more than the sufficiency of oil and gas resources. After several years of decline, coal prices increased by 77% in 2016. The current spot prices are at the level of $80/t and are close to the 2014 prices. In the European market, after the first half of the year, coal prices reached the level of around 66% higher than in the same period of the last year. The average price in the first half amounted to PLN 12.6/GJ, which is close to the 2012 prices. The share of spot trade in the total purchase amount accounted to approx. 20%. Prices in futures contracts can be estimated on the basis of the Japan-Australia contracts prices and prices in supplies to power plants located in Germany. On average, the prices in supplies to these power plants were higher by approximately 9% in the years 2010–2016 and prices in Australia – Japan contracts were 12% higher than CIF ARA prices in 2017. Global energy coal trade reached about 1.012 billion tonnes in 2016. In 2019, a decline by 4.8% is expected primarily due to the expected reduction in the demand in major importing countries in Asia.

Describing the gas boiler fuel consumption as a time series gives the opportunity to use tools appropriate for the processing of such data to analyze this phenomenon. One of them are ARIMA models. The article proposes this type of model to be used for predicting monthly gas consumption in a boiler room working for heating and hot water preparation. The boiler supplies heat to a group of residential buildings. Based on the collected data, three specific models were selected for which the forecast accuracy was assessed. Calculations and analyses were carried out in the R environment using “forecast” and “ggplot2” packages. A good quality of the obtained forecasts has been demonstrated, confirming the usefulness of the proposed analytical tools. The article summary also indicates for what purposes the forecasts obtained in this way can be used. They can be useful for diagnosing the correct operation of a heat source. Registering fuel consumption at a level significantly deviating from the forecast should be a signal to immediately diagnose the boiler room and the heat supply system and to explain the reason for this difference. In this way, it is possible to detect irregularities in the operation of the heat supply system before they are detected by traditional methods. The gas consumption forecast is also useful for optimizing the financial management of the property manager responsible for the operation of the boiler room. On this basis, operating fees or financial operations with the use of periodic surplus capital may be planned.

Wszystkie obiekty budowlane w trakcie użytkowania podlegają procesom starzeniowym o zróżnicowanym przebiegu. Cecha budynku wyrażona przez wartość określoną zbiorem wszystkich czynników fizycznych, które charakteryzują makroskopowe właściwości elementów konstrukcji, określa jego stan techniczny. Stan techniczny jest cechą obiektu budowlanego zmienną w czasie, bezpośrednio związaną z postępującym obniżaniem się właściwości wytrzymałościowych i użytkowych elementów konstrukcji. Proces ten jest nazywany zużyciem technicznym. W ogólnym ujęciu zużycie pozostaje w funkcji czasu i jest określane mianem zużycia naturalnego. Budynki położone w obszarach ujawniania się na powierzchni terenu wpływów eksploatacji górniczej podlegają zwiększonym obciążeniom, które pochodzą od wymuszonej deformacji podłoża budowlanego. Dlatego w przypadku obiektów na terenach górniczych należy mówić o zużyciu technicznym, które jest sumą występowania naturalnych procesów starzeniowych i zużycia wynikającego z pojawiania się uszkodzeń mechanicznych wskutek oddziaływania górniczych deformacji podłoża. Ustalenie wielkości zużycia technicznego obiektu ma znaczenie dla ustalenia wysokości odszkodowania za tzw. szkody górnicze. W praktyce wysokość odszkodowania ustalana jest na podstawie określonej wartości odtworzeniowej budynku pomniejszonej o „wielkość” jego zużycia. W artykule zdefiniowano pojęcie zużycia technicznego na terenach górniczych, omówiono zespół czynników określających stan techniczny budynków podlegających wpływom oddziaływań górniczych. Przedstawiono również autorską metodologię określania globalnego zużycia technicznego budynków o konstrukcji tradycyjnej położonych w granicach terenów górniczych.

Po energetyce zawodowej sektor drobnych odbiorców jest drugim ważnym konsumentem węgla energetycznego w Polsce, w latach 2005–2015 zużywającym 10,3–14,3 mln ton węgla (15– –22% w skali kraju). Statystycznie wyróżniane są w nim trzy grupy konsumentów: gospodarstwa domowe, rolnictwo oraz tzw. pozostali odbiorcy, z których najbardziej znaczącą rolę odgrywają gospodarstwa domowe (77–81% rocznego zużycia węgla przez cały sektor). Udział rolnictwa wynosił 12–14% (1,4–1,8 mln ton węgla na rok), a pozostałe kilka procent – grupa pozostałych odbiorców (0,9–1,1 mln ton). Zużycie węgla w całym sektorze, jak również w każdej z grup statystycznych zróżnicowane jest zarówno pod względem regionalnym, jak również wojewódzkim. Pod względem wolumenu największe zużycie węgla przypada na gospodarstwa domowe z regionu N-E (1,9– –2,9 mln ton). W przypadku rolnictwa są to regiony północne (57–62%; łącznie: 0,8–1,1 mln ton węgla/rok). W artykule przeprowadzono także szacunkowy podział mieszkań wg trzech nośników głównych nośników energii zużytych w celach grzewczych: paliwa stałe (dominuje węgiel kamienny), ciepło sieciowe i gaz ziemny. Stwierdzono, że pod względem regionalnym największym udziałem mieszkań opalanych węglem kamiennym dysponują dwa regiony (reg. S-W i N-E; po 26%). Obliczono także koszty ogrzewania przykładowego domu jednorodzinnego położonego na wsi. Wzięto pod uwagę te nośniki energii, które są najbardziej dostępne dla obszarów wiejskich. W wyniku analizy stwierdzono, że węgiel kamienny byłby jednym z najtańszych paliw. Koszty rocznego ogrzewania domu węglem grubym, czy ekogroszkiem nie przekroczyłyby 3 tys. złotych/rok (wg cen z 2016 r.).

The heat supply systems energy efficiency improvement requires the use of increasingly complex methods. The basic ways to reduce heat consumption is by using better thermal insulation, although they have more and more limited possibilities and need relatively large financial outlays. Good effects can be achieved by the better heat source adaptation to the conditions of a specific facility supplied with heat. However, this requires research that identifies the effectiveness of such solutions as well as the tools used to describe selected elements of the system or its entirety. The article presents the results of tests carried out for a gas boiler room supplying heat to a group of residential buildings. The goal was to build a model that would forecast the day range in which the maximum gas consumption occurs for a given day. Having measurements of gas consumption in subsequent hours of the day, it was decided to build a forecasting model determining the part of the day in which such a maximum would occur. To create the model the random forest procedure was used along with the mlr (Kassambara) package. The model’s hyperparameters were tuned based on historical data. Based on data for another period of boiler room operation, the results of the model’s quality assessment were presented. Close to 44% efficiency was achieved. Tuning the model improved its predictive ability.

Coal production in 2018 increased by 3.3% and amounted to 7.81 million tons. Compared to 2010, it increased by 620 million tons. The structure of coal production in the world is very stable in the analyzed period of 2010–2018. Steam coal dominates in production with a share of 77%. Since 1990, the share of coal in the consumption of primary energy carriers has fallen by 3% in the global economy. In the EU, the share of coal in the consumption of primary energy carriers is more than twice lower than in the world, and in 2018 amounted to 13%. BP estimates the sufficiency of coal proven reserves based on 2018 data for the next 132 years. For oil and gas, they are estimated at 51 years. The decline in hard coal production in the European U nion can be dated almost continuously since 1990, which has decreased by 74%. In 2018, 74 million tons of coal were produced in the EU. In 2018, hard coal consumption in EU countries dropped to 226 million tons, i.e. by 20.6%.

In 2018, global trade in steam coal amounted to 1.14 billion tons. The situation in China is crucial for the international coal market. The slight change in the import policy of this country significantly affects the situation in international trade in steam coal. In 2019, coal prices (at Newcastle, Richards Bay, ARA ports) dropped by an average of 23 U SD/ton. The average decreases for these three indices were 33%. The prices of steam coal in the forecasts presented in the paper are under pressure of the falling demand.

The paper presents selected issues related to the development of international coal markets. World consumption of coal dropped for the second year in a row in 2016, primarily due to the lower demand from China and the US. The share of coal in global primary energy consumption decreased to 28%. World coal production accounted to 3.66 billion toe and it was lower by 6.2% when compared to the previous year. More than 60% of this decline took place in China. The decline in global production was more than four times higher than the decrease in consumption. The sufficiency of the world resources of coal are estimated at 153 years – that is three times more than the sufficiency of oil and gas resources. After several years of decline, coal prices increased by 77% in 2016. The current spot prices are at the level of $80/ton and are close to the 2014 prices. In the European market, after the first half of the year, coal prices reached the level of around 66% higher than in the same period of the last year. The average price in the first half amounted to PLN 12.6/GJ, which is close to the 2012 prices. The share of spot trade in the total purchase amount accounted to approx. 20%. Prices in futures contracts can be estimated on the basis of the Japan-Australia contracts prices and prices in supplies to power plants located in Germany. On average, the prices in supplies to these power plants were higher by approximately 9% in the years 2010 – 2016 and prices in Australia – Japan contracts were 12% higher than CIF ARA prices in 2017. Global energy coal trade reached about 1.012 billion tons in 2016. A decline by 4.8% is expected in 2019 primarily due to the expected reduction in demand in major importing countries in Asia.

Primary energy consumption depends on the size of the economy and its structure, including both industrial and service sectors, characterized by different energy demands. Some of the basic energy and economic indicators that can be used to analyze primary energy consumption include energy intensity, energy productivity and indicators measuring the activity of the economy (gross domestic product or gross value added). In the years 1995–2021, the Polish economy developed at a relatively constant pace, and the value of gross domestic product increased in real terms by almost 290% over the entire analyzed period. However, despite this increase, total primary energy consumption remained at the relatively constant level of around 3,800–4,600 PJ/year. This was caused by, among other factors, an increase in energy productivity on the one hand and a reduction in energy intensity on the other. It should be emphasized that a descriptive analysis of changes in primary energy consumption in Poland in the analyzed period, including changes in selected energy and economic indicators, does not allow the identification and quantification of the impact of all key factors on the total change of the examined value over time. In this context, the main aim of the research presented in this paper is to propose a decomposition model of primary energy consumption in Poland and adapt it to conduct analyses covering the period of economic and energy transition to quantitatively determine the impact of the identified factors on the total change in primary energy consumption in the 1995–2021 period. To perform the described research, decomposition analysis was applied, including a multiplicative and additive approach. A decomposition model was developed based on the formulated decomposition identity. Mathematical formulas of two methods were used to perform the calculations: a generalized Fisher index and the logarithmic mean Divisia index (LMDI). The obtained results indicate that the effects of demand and energy intensity factors had the most significant impact on the primary energy consumption change.

W bieżącym stuleciu stosowane są dwa najczęściej spotykane sposoby zaopatrzenia w ciepło kompleksów budynków wielolokalowych. Pierwszym z nich jest zasilanie w ciepło systemowe z sieci ciepłowniczej, a drugim – budowa i eksploatacja lokalnych kotłowni gazowych. Wykorzystanie innych nośników ciepła występuje tylko wówczas, gdy nie jest możliwe podłączenie źródła ciepła do sieci gazowej lub sieci ciepłowniczej. Budynki wielolokalowe charakteryzują się daleko idącą specyfiką w wielu obszarach swojego funkcjonowania, w tym także w zakresie zużycia ciepła. W przypadku kotłowni gazowych konsumpcja ciepła bezpośrednio przekłada się na pobór paliwa gazowego. W artykule przedstawiono i scharakteryzowano zużycie paliwa gazowego przez lokalną dwufunkcyjną kotłownię na podstawie pomiarów wykonywanych z dużą częstotliwością odczytu. Wiedza na temat procesu poboru gazu, nawet w przypadku jeżeli dotyczy to niewielkich ilości, w skali zużycia krajowego, może być podstawą dla poprawy przebiegu tego procesu. Dotyczyć może to nie tylko aspektu ekonomicznego, ale również technicznego, a także punktu widzenia bezpieczeństwa energetycznego oraz efektywności energetycznej. Z tego względu wszystkie podmioty związane z dostawą i odbiorem paliwa gazowego dla zespołu budynków wielolokalowych powinny być zainteresowane poszerzeniem wiedzy na temat tego procesu.

The article presents the directions of foundry waste management, mainly used for spent foundry sands (SFS) and dust after the reclamation of this waste. An important aspect of environmental protection in foundry production is the reduction of the amount of generated waste as a result of SFS regeneration. The advantage is the reuse of waste, which reduces the costs of raw materials purchase and environmental fees for landfilling. Non -recycled spent foundry sands can be used in other industries. SFS is most often used in road and construction industries as well as inert material in closed mines (Smoluchowska and Zgut 2005; Bany-Kowalska 2006). An interesting direction of using SFS is its application in gardening and agriculture. The article presents the advantages and disadvantages of such use. It was found that spent foundry sands can be useful for the production of soil mixtures for many agricultural and horticultural applications. Due to the possibility of environmental pollution with heavy metals and organic compounds, such an application is recommended for the so-called green sands, i.e. SFS with mineral binders. In addition, an innovative solution for the energy use of dusts after spent foundry sands reclamation with organic binders has been discussed and proposed by some researchers. It was shown that dust from reclaimed SFS with organic binders can be used as an alternative fuel and raw material in cement kilns, due to the high percentage of organic substances which determine their calorific value and silica.