Ground-source

Ground-source heat pumps Ground-source heat pumps have become a success story in several countries and climates, especially in colder regions. Market growth estimates range from 10 to 30% annually. Development of this technology has made significant progress during the past decade. However, further improvements in designing and reducing costs can be made. Reduction of initial cost has mainly been achieved through improved performance, which allows smaller, less costly heat exchangers, and more accurate design analyses. The conference devoted an entire session to this topic.
Ground-source heat pumps have not only seen significant market growth and broadened application; they are becoming recognised as a cost-effective standard for energy conservation. Key factors behind this success are soundness of the technology, improved design and installation infrastructure and the response of the heat pump industry. Current developments focus on five areas: • reducing initial costs of ground heat exchangers; • determining soil thermal properties; • modelling ground-source heat pump systems; •development of hybrid systems (ground heat exchanger combined with above ground heat rejecter/ absorber); • further development of design methodologies; •faster, lower cost pipe-joining methods; •new pumping configurations (variable speed, multiple and zoned on-off pumps).
In the US, there are three ARI certification standards, which rate so-called water-source heat pumps (water source, groundwater source and ground-source closed loop). The worldwide installed capacity and energy produced with ground-source heat pump systems is estimated at 6,675 MW and 23,270 TJ annually