In this article, a comparison of economic effectiveness of various heating systems dedicated to residential applications is presented: a natural gas-fueled micro-cogeneration (micro-combined heat and power – μCHP) unit based on a free-piston Stirling engine that generates additional electric energy; and three so-called classical heating systems based on: gas boiler, coal boiler, and a heat pump. Calculation includes covering the demand for electricity, which is purchased from the grid or produced in residential system. The presented analyses are partially based on an experimental investigation. The measurements of the heat pump system as well as those of the energy (electricity and heat) demand profiles in the analyzed building were conducted for a single-family house. The measurements of the μCHP unit were made using a laboratory stand prepared for simulating a variable heat demand. The overall efficiency of the μCHP was in the range of 88.6– 92.4%. The amounts of the produced/consumed energy (electricity, heat, and chemical energy of fuel) were determined. The consumption and the generation of electricity were settled on a daily basis. Operational costs of the heat pump system or coal boiler based heating system are lower comparing to the micro-cogeneration, however no support system for natural gas-based μCHP system is included.
The energy saving tendencies, in reference to residential buildings, can be recently seen in Europe and in the world. Therefore, there are a lot of studies being conducted aiming to find technical solutions in order to improve the energy efficiency of existing, modernized, and also new buildings. However, there are obligatory solutions and requirements, which must be implemented during designing stage of the building envelope and its heating/cooling system. They are gathered in the national regulations. The paper describes the process of raising the energy standard of buildings between 1974–2021 in Poland. Therefore, the objective of this study is to show energy savings, which can be generated by modernization of thermal insulation of partitions of existing buildings and by the use of different ways of heat supply. The calculations are made on the selected multi-family buildings located in Poland, with the assumption of a 15 years payback time. It is shown that it is not possible to cover the costs of the modernization works by the projected savings with the compliance to the assumption of 15 years payback time.