Original Title:
Greenhouse heating and cooling performance assessment using a novel CO2 ground-source heat-pump
Languages of Item:
English
Creator:
Syngounas, Evangelos
Tsimpoukis, Dimitrios
Koukou, Maria K.
Vrachopoulos, Michail Gr.
Affiliation:
Energy and Environmental Research Laboratory, Department of Agricultural Development, Agrofood and Management of Natural Resources, National and Kapodistrian University of Athens, Psachna, Greece
Abstract:
Recent EU legislation and proposals concerning the gradual phase-out of refrigerant
substances with either high GWP or negative impact on human health (F-gas regulation, PFAS
ban), lead to the promotion of carbon dioxide (R744) as the most viable and long-term
refrigerant alternative for the refrigeration and air-condition systems. In the meantime, the
integration of RES in the refrigeration configurations seems necessary for the climate
neutrality EU goal by 2050 (Green Deal). The current study presents a theoretical energy
analysis of a novel ground-source heat pump with R744 refrigerant for covering the heating
and cooling needs of a greenhouse plant in the Psachna region. The proposed arrangement
uses a vapor ejector for the reduction of the working compression ratio, plus it integrates a
swallow geothermal heat exchanger for heat rejection and absorption during the summer and
winter periods respectively. The energetic assessment uses validated numerical models
developed in MATLAB using CoolProp library. Results show efficiency rates increment up to
16% for the heating mode and up to 13% for the cooling mode respectively for the proposed
topology compared to a conventional air-cooled system. The average annual improvement of
COP is 7%, which leads to electricity savings of 59.48 MWh/year in comparison to the
conventional case.
Main subject category:
Energy
Other subject categories:
Environment
Keywords:
refrigeration and air-condition systems
Greenhouse
carbon dioxide
