Earth Notes: General Bibliography (lammle2022performance)

• [lammle2022performance] Lämmle, Manuel and Bongs, Constanze and Wapler, Jeannette and Günther, Danny and Hess, Stefan et al. Performance of air and ground source heat pumps retrofitted to radiator heating systems and measures to reduce space heating temperatures in existing buildings (accessed 2023-05-22), Elsevier, 2022, Energy, volume 242, doi:10.1016/j.energy.2021.122952, article/pages 122952 (article) (BibTeX).
  abstract

  Heat pumps are expected to play a central role in decarbonizing heat supply, but face challenges in existing buildings due to high temperature requirements of existing radiator systems. This paper links the performance analysis of heat pump systems with methods to reduce temperatures of the space heating circuit. Field data and system simulations of air and ground source heat pumps show a linear correlation between the seasonal performance factor SPF and the mean heat pump temperature over a wide temperature range. Every Kelvin of reduced heat pump temperature increases the SPF by 0.10-0.13 points. Applied methods to reduce heating temperatures are demonstrated at existing multi-family buildings. Thermal insulation reduces the building's heat load, allowing a reduction of heating temperatures with the existing radiators. A further temperature reduction is achieved by analyzing the required heating power per room and identifying critical, undersized radiators. In a studied building, the selective exchange of only 7% of all radiators is sufficient to reduce heating temperatures from 75 °C/60 °C-55 °C/45 °C. This corresponds to a reduction of the electricity consumption by 40-42%. However, the potential of these methods is specific for each building and depends particularly on its renovation state and installed radiator capacity. Nonetheless, an energy- and cost-efficient operation of heat pumps retrofitted in existing radiator heating systems is viable, if following the proposed system design method linking heat pump performance and reduction of space heating temperatures.
  note

  [Many good references. Modelling with Dymola/Modelica with libraries Buildings, AixLib], and IBPSA. Quote: "The design heat load per room is calculated according to EN 12831-1:2017." Also EN ISO 13790:2008 / 5R2C. No (micro)zoning. Quote: "Every Kelvin of reduced [mean] heat pump temperature increases the SPF by 0.10-0.13 points [GSHP, ASHP]." Along with improved building envelope insulation ... Quote: "A large potential to reduce temperatures can be exploited by analyzing heat load and radiator capacity on room level with the aim to identify and exchange critical radiators, which limit a further reduction of system temperatures." ... "which can reduce heating costs of up to 24%."]