Dear Colleagues,

Awareness of the increase in the global temperature continuously grows, and a new target has been set by the Paris Agreement. The use of hydrocarbon-based fuels forms the lion’s share of CO_2e emissions. The building sector is one of the largest energy consumers globally, with the majority used for heating ventilation and air conditioning (HVAC) systems. Currently, solar and shallow geothermal systems can be used to displace conventional energy systems based on hydrocarbons. Although both technologies are well developed, the combined concept of the solar-assisted ground source heat pump (SAGSHP) system has not been thoroughly investigated. In recent decades, effort has been made to evaluate the SAGSHP systems for different climatic conditions, but no line can be drawn regarding their best design practice. This Special Issue of Energies, “Novel design of solar assisted ground source heat pump systems”, is focused on the new methodologies, operation strategies, system topologies, optimization frameworks and techniques that can assist the applicability of the SAGSHP, solar assisted and ground source heat pump systems.

Topics include, but are not limited to, the following:

• Optimization for solar and geothermal heat pump systems;
• Energy storage on solar and geothermal heat pump systems;
• Solar and geothermal heat pump systems for DHW;
• Solar and geothermal heat pump systems for space heating and cooling;
• Novel geothermal heat exchangers;
• Modelling and simulation of the solar and geothermal heat pump systems;
• Experimental evaluation of SAGSHP systems;
• Novel solar and geothermal heat pump systems’ topology;
• Photovoltaic thermal collectors and geothermal systems;
• Very shallow geothermal heat exchangers for SAGSHP systems;
• Economic assessment of Photovoltaic thermal collectors and geothermal systems;

Prof. Dr. Axaopoulos Petros
Dr. Evangelos Sakellariou
Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Energies is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

• Solar-assisted ground-source heat pump
• Geothermal heat exchanger
• Photovoltaic thermal collector
• Earth energy bank
• Solar-assisted systems
• Solar thermal collectors
• Shallow geothermal systems
• Multi-energy-source heating systems
• Long-term heat storage
• Heat pumps
• Solar systems
• Borehole heat exchanger
• Uncovered solar collector