Ground-Source Heat Pumps

The major drawback to using ground-source heat pumps lies in the high initial cost of the systems, mostly because of the underground heat exchanger. Savings can be made through a better understanding of the behaviour of the heat exchanger and its interaction with the ground. Smaller, more efficient and less expensive exchangers can then be developed. More detailed information on the behaviour of new refrigerants is also necessary to maximize the efficiency of components. New refrigerants that are less harmful to the environment are also required.

No standards exist for community-based heating applications; therefore, contractors are reluctant to recommend these energy efficient systems. Demonstration sites are necessary to obtain data and develop guidelines. This would also validate the feasibility of using ground-source heat pumps for a community application.

CanmetENERGY’s research activities are focused on:

• Development of a ground-source heat pump with CO₂ in a secondary loop and a phase change
• Direct expansion systems
• Ground-source storage for community heating

CanmetENERGY is seeking research partnerships with universities and industries that share its interest in improving energy efficiency in buildings and reducing greenhouse gas emissions. To discuss a partnership, contact us.

Development of a ground-source heat pump with CO₂ in a secondary loop and a phase change

Because of its thermophysical and transport properties, as well as its environmental benefits, carbon dioxide, which is among the natural fluids, offers the best alternative to synthetic refrigerants. A research project is underway to study the behaviour of a ground-source heat pump system using CO₂ with a phase change in a secondary ground loop. A theoretical model will be developed to predict thermal and hydrodynamic phenomena produced by the ground heat exchanger. A test bed will be used to validate the theoretical model and study the dynamic behaviour of exchangers.

Direct expansion (DX) systems

DX systems are the preferred option for ground-source heat pumps in North America. However, designers are faced with a lack of technical data to optimize systems and replace synthetic refrigerants in order to respond to environmental concerns. The replacement of R-22 with a more environmentally friendly refrigerant like R-410a will be studied. The project includes field tests and the development of a simulation model.

Ground-source storage for community heating

Follow-up and an assessment of existing community heating systems, where ground-source heat pumps are integrated into a thermal energy storage system, will be conducted. These systems are equipped with controllers to efficiently manage the heating and air conditioning between residential buildings and exothermic buildings, such as supermarkets and arenas. The results of these assessments will help to develop guidelines and improve the planning and development of these systems.

Managed by CanmetENERGY at the Varennes (Quebec) research centre.