Integration of Back-Up Heaters in Retrofit Heat Pump Systems: Which to Choose, Where to Place, and How to Control?

Wüllhorst, Fabian; Vering, Christian; Maier, Laura; Müller, Dirk

doi:10.3390/en15197134

Cited by 5 publications

(2 citation statements)

References 26 publications

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“…A local controller actuates the different components based on these setpoints. The local control follows the approach in [31] and is depicted in the right part of Figure 1. Two hystereses decide whether the heat pump and heating rod turn on or off for space heating and DHW.…”

Section: Local Controlmentioning

confidence: 99%

Heat Pump Systems with Photovoltaics: Influence of the Control Strategy on the Optimal Design

Wüllhorst

Reuter-Schniete

Maier

et al. 2023

36th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems (ECOS 20

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Electrifying the heat supply of buildings is key to mitigate climate change. Inhere, photovoltaic and heat pump systems are promising technologies. Studies indicate that an increase in self-consumption is economically beneficial. Coupling photovoltaic with heat pump systems enables the aspired increase of self-consumption, especially in combination with thermal energy storages. The coupling of the systems is influenced by the control strategies, for which rule-based and model predictive-based approaches exist. Research finds that optimal control methods heavily depend on the system design and vice versa. Contrary to these interdependencies, current design guidelines neglect a possible influence of photovoltaics on the design of the heat pump system. To analyze a possible influence on the optimal heat pump system design, we apply nonlinear, dynamic simulation-based optimization to find the optimal design of the heat pump system for three different cases: no photovoltaic, no supervisory control, and a state-of-the-art supervisory control. The model consists of the whole building energy system, including the building envelope, radiators, a heat pump, a photovoltaic, and a grid connection. The dynamic simulation covers a whole year. To obtain generalizable results, we conduct optimizations for varying boundary conditions, including changes in weather and photovoltaic roof area. Consistent over all boundary conditions, results indicate that cost optimal heat pump system design does not change for current price assumptions. However, maximizing the thermal energy storage is vital to obtain maximal costs savings compared to the case with no photovoltaic system. Thus, for different price assumptions, the optimal design will change.

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Section: Local Controlmentioning

confidence: 99%

Heat Pump Systems with Photovoltaics: Influence of the Control Strategy on the Optimal Design

Wüllhorst

Reuter-Schniete

Maier

et al. 2023

36th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems (ECOS 20

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“…[ 17 ] Alternatively, hybrid, bivalent HP systems combine HPs with a secondary heat generator, e.g., a gas boiler, so that temperature and power requirements of existing MFH can be reached. [ 18 ]…”

Section: Introductionmentioning

confidence: 99%

Heat Pump Systems in Existing Multifamily Buildings: A Meta‐Analysis of Field Measurement Data Focusing on the Relationship of Temperature and Performance of Heat Pump Systems

Lämmle,

Metz,

Kropp

et al. 2023

Energy Tech

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Heat pumps play a central role in decarbonizing the heat supply of buildings. However, implementing heat pumps in existing buildings, still presents a significant challenge due to high temperature requirements. In this paper, we present a systematic analysis of the effects of heat source temperatures, maximum heat pump condenser temperatures, and system temperatures on the seasonal performance of heat pump systems. The quantitative performance analysis encompasses over 50 heat pumps installed in residential buildings, revealing correlations between the building characteristics, observed temperatures, and heat pump type. The performance of a heat pump system retrofitted to a 30‐dwelling multifamily building is presented in more detail. The bivalent heat pump system combines air and ground as heat sources and achieves a seasonal performance factor of 3.25 with a share of the gas boiler of 27% for the provision of space heating and domestic hot water in its first year of operation. These findings demonstrate the technical feasibility of retrofitting heat pumps in existing buildings and provide insights into overcoming the challenges associated with high temperature requirements.This article is protected by copyright. All rights reserved.

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Alternatives for upgrading from high-temperature to low-temperature heating systems in existing buildings: Challenges and opportunities

Roca Reina,

Toleikyte,

Volt

et al. 2024

Energy and Buildings

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Integration of Back-Up Heaters in Retrofit Heat Pump Systems: Which to Choose, Where to Place, and How to Control?

Cited by 5 publications

References 26 publications

Heat Pump Systems with Photovoltaics: Influence of the Control Strategy on the Optimal Design

Heat Pump Systems with Photovoltaics: Influence of the Control Strategy on the Optimal Design

Heat Pump Systems in Existing Multifamily Buildings: A Meta‐Analysis of Field Measurement Data Focusing on the Relationship of Temperature and Performance of Heat Pump Systems

Alternatives for upgrading from high-temperature to low-temperature heating systems in existing buildings: Challenges and opportunities

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