Paweł Obstawski

The objective of this paper is to review modern design solutions applied to vapor-compression heat pumps using the environmentally friendly refrigerant propane (R290), with particular emphasis on refrigerant charge minimization and its impact on system energy performance, and to discuss the influence of compressor type, heat exchanger configuration, and the application of thermoelectric subcooling technology on the coefficient of performance and the seasonal coefficient of performance. Additionally, we examined the effects of supply voltage, water temperature, and climatic location on system efficiency. The reviewed results indicate significant potential for further optimization of heat pumps using R290 while simultaneously meeting safety and energy efficiency requirements.

The stretch film production is highly energy intensive. The components of the technological line are powered by electrical energy, and the heat is used to change the physical state of the raw material (granules). The raw material is poured into FCR (the first calender roller). To solidify the liquid raw material, the calendar must be cooled. The low-temperature heat, treated as waste heat, has dissipated in the atmosphere. Technological innovations were proposed: (a) the raw material comprises raw material (primary) and up to 80% recyclate (waste originating mainly from agriculture), (b) the use of low-temperature waste heat (the cooling of FCR in the process of foil stretch production). A heat recovery line based on two compressor heat pumps (HP, hydraulically coupled) was designed. The waste heat (by low-temperature HP) was transformed into high-temperature heat (by high-temperature HP) and used to prepare the raw material. The proposed technological line enables the management of difficult-to-manage post-production waste (i.e., agriculture and other economic sectors). It reduces energy consumption and raw materials from non-renewable sources (CO₂ and other greenhouse gas emissions are reducing). It implements a closed-loop economy based on renewable energy sources (according to the European Green Deal).

The main aim of this article is estimation of the heating energy demand and annual heating costs for classical sacral building equipped with ground source heat pump or gas boiler. For this purposes a simulation model in the Matlab Simulink 2022b has been developed. Heat losses through the...

The production technology for stretch film is highly energy-intensive. Electrical energy is used not only to power individual components of the technological line but also to change the physical state of the raw material (granules) from solid to liquid, which is poured onto the first calender roller. The calender roller must be cooled to solidify the liquid raw material, and the low-temperature heat generated in this process has been treated so far as waste heat and dispersed into the atmosphere. A low-temperature process heat recovery line has been developed, enabling its transformation into high-temperature heat. High-temperature process heat can be utilized in the technological process for the preliminary preparation of raw material when recycled material (regranulate) with highly variable parameters is added to the base material (granules) with strict specifications. The regranulate content can be as high as 80%. The waste heat recovery system is based on two compressor heat pumps powered by eco-friendly refrigerants. This innovative solution facilitates a circular economy, reduces the carbon footprint, and aligns with the European Green Deal.

The article presents a project of an innovative technological line for producing stretch foil. The technological innovation consists of the fact that the foil is produced from a material composed of primary raw material and up to 80% recyclate. The new product cannot be used differently from the...

The paper presents an analysis of the cooling performance of a microchannel beam heat exchanger powered by the combustible refrigerant R290 (propane) as a function of design parameters. R290 is an environmentally friendly refrigerant, in the context of growing concerns about climate change and...

This paper presents a comparative analysis of a finned heat exchanger fed with synthetic refrigerant R410a and environmentally friendly refrigerant R290. Analyses of the performance of the heat exchanger operating as an evaporator in a refrigeration system were carried out. Simulation studies...

The paper presents the design of a two-stage subcritical compressor heat pump operating in an air-to-water system and running on environmentally friendly refrigerants. The pump is dedicated to buildings where there is a high-temperature central heating system and wall-mounted radiators are used...

The decarbonization of heating systems is one of the present political and legislative directions of the European Union and its Member States. The main activities concern the energy performance of buildings and energy efficiency. The mentioned UE directives are the basis for the financial support of high-emission fossil fuel thermal energy source replacement with emission-free ones, in particular heat pumps. Other aspects are the support of PV installations and the thermal insulation of buildings. 85% of EU buildings were built before 2000, and among those, 75% have poor energy performance. Therefore, a significant number of buildings have only high-temperature wall radiators, and this was a motivation to prepare this article. The main innovation of this research was a new theoretical design of a high-temperature heat pump based on ecological refrigerants. The presented solution allows wall radiators to receive a hot water supply with temperatures of up to 85 °C during external temperatures of up to −20 °C. Typical heat pumps do not have these kinds of parameters, so the authors decided to verify the possibility of operating this device in such a wide temperature range. Another important aspect was the analysis of PV support. Finally, this paper investigates the possibility of heating an energy-efficient house with the newly designed high-temperature heat pump. Depending on the location in Poland, i.e., Suwałki, Warsaw, and Wrocław, the total electric energy supplied to the compressors was 2538–3364 kWh. The energy provided by the PV to supply power to the compressors is 482–570 kWh. The achieved PV energy self-consumption is 16.9–19.0%. The Seasonal Coefficient of Performance (SCOP) of the heat pump is 1.825–2.038 without PV and 2.515–2.970 with PV.

This paper introduces a compressor heat pump model using flow rate and enthalpy values for the calculation of heat pump control parameters. The aim of in this article presented research work was to develop an universal model of a compressor heat pump which will enable simulation tests for...