Energy-Efficient Integration of Air-to-Water Heat Pumps in Office Buildings
Sevelius, Max (2025)
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:amk-2025120934001
https://urn.fi/URN:NBN:fi:amk-2025120934001
Tiivistelmä
This thesis examines an energy-efficient retrofit concept in which old chiller systems in office
buildings are replaced with air-to-water heat pumps that are integrated to the existing cooling network. The aim is to improve heating and cooling efficiency, reduce the district heating consumption, and enable cost-effective integration of renewable energy technologies in line with EU and Finnish energy policies.
The study investigates the usage of cooling coils repurposed as low-temperature heating coils while bypassing the district heating connection requirements. The research uses manufacturer data, dimensioning reports, and dynamic modelling in Simulink to simulate an air handling unit equipped with a rotating heat recovery unit and integrated with air-to-water heat pump produced heating.
A control program was developed to validate the control concept, including air-to-water heat pump operation, automation control strategies, freeze protection, and supply-air temperature control. The model is based on measured temperature data and includes detailed fan, coil, and heat-recovery calculations. The results show that the air-to-water heat pump can cover 87 % of the AHU’s external heating demand and reduce DH consumption by 408 MWh annually, corresponding to yearly cost savings of approximately 45 200 € in Helsinki. The retrofit is also able to reduce electricity usage when combined with fan upgrades and modern control systems.
The findings align with documented energy-efficiency projects, demonstrating district heating reductions of over 50 % and payback times under five years. The study concludes that the proposed AWHP retrofit concept is technically feasible, economically competitive, and broadly applicable to Finnish office buildings equipped with their own cooling units.
buildings are replaced with air-to-water heat pumps that are integrated to the existing cooling network. The aim is to improve heating and cooling efficiency, reduce the district heating consumption, and enable cost-effective integration of renewable energy technologies in line with EU and Finnish energy policies.
The study investigates the usage of cooling coils repurposed as low-temperature heating coils while bypassing the district heating connection requirements. The research uses manufacturer data, dimensioning reports, and dynamic modelling in Simulink to simulate an air handling unit equipped with a rotating heat recovery unit and integrated with air-to-water heat pump produced heating.
A control program was developed to validate the control concept, including air-to-water heat pump operation, automation control strategies, freeze protection, and supply-air temperature control. The model is based on measured temperature data and includes detailed fan, coil, and heat-recovery calculations. The results show that the air-to-water heat pump can cover 87 % of the AHU’s external heating demand and reduce DH consumption by 408 MWh annually, corresponding to yearly cost savings of approximately 45 200 € in Helsinki. The retrofit is also able to reduce electricity usage when combined with fan upgrades and modern control systems.
The findings align with documented energy-efficiency projects, demonstrating district heating reductions of over 50 % and payback times under five years. The study concludes that the proposed AWHP retrofit concept is technically feasible, economically competitive, and broadly applicable to Finnish office buildings equipped with their own cooling units.