2009-12-23 - The construction of a ground-source heat pump test bench using CO₂ in phase change as heat transfer fluid is in progress at CanmetENERGY. This test bench is part of a project intended to develop knowledge and methods to allow the installation of ground-source heat pumps with CO₂ as secondary refrigerant. The experimental results will be used to validate a conceptual model of prediction of thermal and hydrodynamics phenomena which occur in the underground heat exchanger and to study exchangers’ dynamic behavior.

The ground drilling, as well as the insertion of the tubes in U and the probes of temperature measurement to various depths are now completed.

The test bench will include 3 loops:

• primary loop using refrigerant R507A
• secondary loop with CO₂ including underground exchangers, a circulating pump and a tank
• water loop to transfer heat to the building (heating mode) or to withdraw heat from it (air-conditioning mode)

The ground-source heat pumps are heating and air-conditioning systems which, by exploiting the heat stored in the ground and the heat pump effect can reduce the buildings’ energy needs of approximately 65%. The use of the ground heat as cold source of the heat pump in winter and as heat sink in summer is an interesting solution to maintain high performances, in particular in a cold climate like the one in Canada.

To learn more about CanmetENERGY’s activities related to ground-source heat pumps, see the Heat Pumps section of the website.