Simulation-based investigation of decentralized heat pump system in an existing multi-family building
The building sector's substantial energy consumption, particularly for space and water heating, necessitates a rapid transition towards sustainable technologies. Heat pumps represent a promising, environmentally friendly solution for decarbonizing these demands in existing multi-family building...
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| Tipo de documento: | dissertação |
| Data de publicação: | 2025 |
| País: | España |
| Recursos: | Universitat Politècnica de Catalunya (UPC) |
| Repositório: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglês |
| OAI Identifier: | oai:upcommons.upc.edu:2117/445018 |
| Acesso em linha: | https://hdl.handle.net/2117/445018 |
| Access Level: | Acceso aberto |
| Palavra-chave: | Heat pumps Buildings -- Energy conservation Heat storage Bombes de calor Edificis -- Estalvi d'energia Calor -- Emmagatzematge Àrees temàtiques de la UPC::Energies |
| Resumo: | The building sector's substantial energy consumption, particularly for space and water heating, necessitates a rapid transition towards sustainable technologies. Heat pumps represent a promising, environmentally friendly solution for decarbonizing these demands in existing multi-family buildings. In this study, a comprehensive simulation-based investigation of a decentralized heat pump system integrated into a single-family apartment in Potsdam, Germany was carried out. The study primarily aims to: 1) quantify and compare the energy efficiency and operational performance of phase change material (PCM) based versus water tank-based single storage configurations; and 2) identify and optimize control strategies for these systems to maximize performance, robustness, and occupant comfort under different operating conditions. The methodology involved developing a dynamic co-simulation model in Dymola using Modelica, coupled with a detailed EnergyPlus building model converted into a Functional Mock-up Unit (FMU). This framework facilitated dynamic interaction between the building's thermal behavior and the HVAC components. Key system elements modeled included a heat pump, radiator, and two distinct single-tank storage configurations: a 120 liter (L) water tank and an 80L PCM (PCM58 salt hydrate with a 50°C melting point) tank. Comprehensive control strategies were implemented to manage heat pump operation priority (space heating and domestic hot water demand), regulate pumps, and control valves for temperature maintenance and cycling reduction. Simulations were performed over a full year, with data collected at one-minute intervals. The results were subsequently processed in Python for detailed Key Performance Indicator (KPI) computation and visualization. The comparative analysis provided significant insights into system efficiency and comfort across different storage configurations. Between water storage tanks, the 120L tank, compared to 60L tank, demonstrated superior performance with reduced heat pump cycling (1852 vs. 2095 cycles) and significantly lower auxiliary heater reliance (1.39 kWh vs. 14.77 kWh), resulting in a slightly higher Seasonal Performance Factor (3.60 vs. 3.56), though it incurred higher storage losses (24 kWh vs. 12 kWh). This highlighted the benefits of larger sensible storage for operational stability. The comparison between the 120L water tank and the 80L PCM storage tank revealed a nuanced tradeoff. The PCM system drastically reduced heat pump cycling (887 vs. 1852 cycles) and total ON time (1314 vs. 1840 hours), suggesting extended compressor longevity and improved apartment temperature stability (337 vs. 949 Kelvin-minutes violation), alongside lower heat pump electricity consumption. However, these advantages were offset by a higher reliance on the electric auxiliary heater (24.49 kWh vs. 1.39 kWh), substantially higher thermal storage losses (112 kWh vs. 24 kWh for the water tank), and a slightly lower overall system SPF (3.28 vs. 3.60). This indicated that while PCM offers excellent thermal buffering and reduces mechanical stress, its effectiveness with rapid DHW demands may require more auxiliary heating. The study successfully quantified these impacts, offering valuable data for optimizing decentralized heat pump systems. |
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