The article presents the results of a study aiming to select the optimal source of heat for a newly designed single-family home. Commercial software was used to compare heating and ventilation systems involving a bituminous coal boiler, a condensing gas boiler, a biomass boiler, a heat pump with water and glycol as heat transfer media. The effectiveness of natural ventilation, mechanical ventilation with a ground-coupled heat exchanger, and solar heater panels for water heating were evaluated. The analysis was based on the annual demand for useful energy, final energy, and non-renewable primary energy in view of the pollution output of the evaluated heating systems. The analysis revealed that the heat pump with water and glycol was the optimal solution. However, the performance of the heat pump in real-life conditions was below its maximum theoretical efficiency. The biomass boiler contributed to the highest reduction in pollutant emissions (according to Intergovernmental Panel on Climate Change Change guidelines, carbon dioxide emissions have zero value), but it was characterized by the highest demand for final energy. Mechanical ventilation with heat recovery was required in all analyzed systems to achieve optimal results. The introduction of mechanical ventilation decreased the demand for final energy by 10% to around 40% relative to the corresponding heating systems with natural ventilation.

The aim of the research was to evaluate the dietary patterns of children aged 10-12 in the city of Olsztyn. The research involved a group of 288 children (144 boys and 144 girls) aged 10-12, living in the city of Olsztyn. Evaluation of dietary patterns was carried out on the basis of individual dietary interviews concerning food intake over the past 24h, followed by determination of energy and nutritional values of the daily diet as well as the content of basic nutrients, such as protein, fat, carbohydrates, microelements and vitamins. The research demonstrated that although the amount of consumed meals was correct, they did not cover the energy requirements of the examined children (in the case of boys, the average energy value of the daily diet was 1960,92 kcal, and for girls it was 1627,7 kcal) and were too poor in protein and carbohydrates. Moreover, it was found that the calcium intake norms were met at the level of approximately 50% of the average demand and an excessively low content of fibre were found in the daily diet. The study results showed the mistakes made by the studied population group in the method of nutrition, including daily diet energy value (deficiencies), its structure and the quality of the meals.