An assessment of the efficiency and emissions of a pellet boiler combusting multiple pellet types

With sustainable energy being the key to reaching climate neutrality, the utilization of nonwooden biomass is a necessity. This article compares the emissions and efficiency of combusting a number of types of agrobiomass and wood pellets. A comparison was made on a moving grate pellet burner mounted in a boiler, where flue gas had a vertical flow via two pass heat exchangers with turbulization elements. Tests were conducted on wood pellets (ENPlus), miscanthus straw pellets, sunflower husk pellets, and corn stover pellets. During combustion, both wood and miscanthus pellets met the PN-EN 303-5:2012 emission and efficiency requirements. Corn stover pellets met the requirement on the nominal capacity. Sunflower husk pellets are characterized by excessive CO and particulate matter emissions. Sunflower husk pellets were the most problematic fuel from the point of view of the results of this research. During combustion of the miscanthus straw pellets there was a need to decrease the nominal heating capacity due to ash sintering

Analysis of the efficiency of a solid fuel boiler depending on the choice of combusted fuel

In the municipal and residential sector in Poland, as many as 50% of households are heated by solid fuel boilers. Most often these are, unfortunately, inefficient boilers, fired with low-quality coal. This study characterizes the market of boilers for solid fuels in Poland, and also presents the main apportionment of these devices, due to the different criteria that characterize them. The current legal changes in the scope of energy and emission requirements for solid fuel boilers are also discussed. The main purpose of this work is to analyze the real efficiency of the solid fuel over-fired boiler used, depending on the fuel burned in it. The process of burning selected fuels (seasoned wood, coal and pea coal) in the boiler was preceded by tests of these fuels to determine their energy parameters, such as moisture, ash content, the share of volatile matter and calorific value. In the next step, the energy efficiency obtained by the tested solid fuel boiler during the combustion of selected solid fuels was compared. The highest efficiency was achieved during the combustion of pea coal, and the lowest was achieved during the combustion of wood. In any case, the nominal efficiency value was achieved. Solutions that could improve the quality of the combustion process in this type of boiler were proposed

The influence of heat sink temperature on the seasonal efficiency of shallow geothermal heat pumps

Geothermal heat pumps, also known as ground source heat pumps (GSHP), are the most efficient heating and cooling technology utilized nowadays. In the AGH-UST Educational and Research Laboratory of Renewable Energy Sources and Energy Saving in Miękinia, shallow geothermal heat is utilized for heating. In the article, the seasonal efficiency of two geothermal heat pump systems are described during the 2014/2015 heating season, defined as the period between 1st October 2014 and 30th April 2015. The first system has 10.9 kW heating capacity (according to European Standard EN 14511 B0W35) and extracts heat from three vertical geothermal loops at a depth of 80m each. During the heating season, tests warmed up the buffer to 40°C. The second system has a 17.03 kW heating capacity and extracts heat from three vertical geothermal loops at a depth of 100 m each, and the temperature of the buffer was 50°C. During the entire heating season, the water temperatures of the buffers was constant. Seasonal performance factors were calculated, defined as the quotient of heat delivered by a heat pump to the system and the sum of electricity consumed by the compressor, source pump, sink pump and controller of heat pumps. The measurements and calculations give the following results: – The first system was supplied with 13 857 kWh/a of heat and consumed 3 388 kWh/a electricity. The SPF was 4.09 and the average temperature of outlet water from heat pump was 40.8°C, and the average temperature of brine flows into the evaporator was 3.7 °C; – The second system was supplied with 12 545 kWh/a of heat and consumed 3 874 kWh/a electricity. The SPF was 3.24 and the average temperature of outlet water from heat pump was 51.6°C, and the average temperature of brine flows into the evaporator was 5.3°C. To summarize, the data shown above presents the real SPF of the two systems. It will be significant in helping to predict the SPF of objects which will be equipped with ground source heat pumps

The concept of low-cost didactic rig in the field of heat pumps

The Centre of Sustainable Development and Energy Saving in Miękinia conducts broad didactic activities for various groups of students. For its own purposes, and also as a concept to use for other didactic centers, a low-cost didactic stand in the scope of heat pumps was designed and implemented. The constructed device presents the operating principles and schematically describes the basic elements of the ground source heat pump system. The device was constructed using a used piston and hermetic compressor from an old fridge. As an evaporator and condenser, a heat exchanger made from copper pipe curved meandering was used. A carefully selected capillary tube was used as an expansion element. The distribution of the components and the visualization of the didactic rig were devised. The whole concept assumed the usage of propane (R290) as an ecological refrigerant. The project also includes cost statements for creating an alternative to a commercial, low-cost stand for teaching purposes at various levels of education and suggests ways of using the set

Ectoine in the treatment of ocular allergy

The increase in the number of cases of allergic diseases in various organs caused that they are now regarded as a social diseases. It is often interdisciplinary problem due to the simultaneous occurrence of symptoms in several organs. Allergic conjunctivitis (AC) is becoming more prevalent throughout the world and is one of the most common diseases of anterior eye segment. Ectoine has been used in many aspects of medicine to reduce symptoms of allergic diseases. Preparations containing ectoine are an innovative alternative treatment for patients with allergic diseases

Analysis of the cooling of PV modules with water on their efficiency

The article presents the results of research on the efficiency of photovoltaic modules cooled by water. The purpose of the experiment was to improve the working conditions of the solar cells. Lowering the cell temperature increases the power generated by the device. The decrease in the temperature of the PV module was obtained by pouring water on the upper surface of the cells, as rain imitation or a water film. The power of the cooled and non-cooled devices were compared. The best results were achieved by cooling cells with a water film since there were no water splashes. The continuous cooling of cells surface causes a 20% increase of device's power. During the test, the non-cooled module reached the maximum power of 172 W, while the cooled one - 205 W. Cooling the module resulted in an increase in power by 33 W. In addition, the temperature of the cells dropped to almost 25°C. At this time, the temperature of the non-cooled module was 45°C. The presented solution may be an interesting proposition for small installations. The solution can also be an alternative for cleaning the modules due to the improvement in the power of the module after the test in terms of their power before

Upgrading a District Heating System by Means of the Integration of Modular Heat Pumps, Geothermal Waters, and PVs for Resilient and Sustainable Urban Energy

Krakow has an extensive district heating network, which is approximately 900 km long. It is the second largest city in terms of the number of inhabitants in Poland, resulting in a high demand for energy—for both heating and cooling. The district heating of the city is based on coal. The paper presents the conception of using the available renewable sources to integrate them into the city’s heating system, increasing the flexibility of the system and its decentralization. An innovative solution of the use of hybrid, modular heat pumps with power dependent on the needs of customers in a given location and combining them with geothermal waters and photovoltaics is presented. The potential of deep geothermal waters is based on two reservoirs built of carbonate rocks, namely Devonian and Upper Jurassic, which mainly consist of dolomite and limestone. The theoretical potential of water intake equal to the nominal heating capacity of a geothermal installation is estimated at 3.3 and 2.0 MW, respectively. Shallow geothermal energy potential varies within the city, reflecting the complex geological structure of the city. Apart from typical borehole heat exchangers (BHEs), the shallower water levels may represent a significant potential source for both heating and cooling by means of water heat pumps. For the heating network, it has been proposed to use modular heat pumps with hybrid sources, which will allow for the flexible development of the network in places previously unavailable or unprofitable. In the case of balancing production and demand, a photovoltaic installation can be an effective and sufficient source of electricity that will cover the annual electricity demand generated by the heat pump installation, when it is used for both heating and cooling. The alternating demand of facilities for heating and cooling energy, caused by changes in the seasons, suggests potential for using seasonal cold and heat storage