Natural refrigerants are substances that exist naturally in the environment. With zero ozone depletion potential (ODP) and very low or zero global warming potential (GWP), they are considered the definitive solution to the environmental damage caused by synthetic refrigerants.
The most widespread natural refrigerants used in HVAC/R applications today are carbon dioxide (CO2, R-744), hydrocarbons such as propane (R-290), isobutane (R-600a) and propylene (R-1270), and ammonia (NH3, R-717). In particular, CO2 and propane are the most widely-used in retail applications, in both centralised and decentralised architectures.
CAREL’s solutions have always been developed to guarantee high efficiency, even with natural refrigerants and especially for CO2 and propane, which are very common in Europe.
CAREL has been acquiring vast experience working on a number of projects for centralised installations using condensing units with Hecu and compact racks with multi DC for CO2, as well as waterloop stores with semi plug-in cabinets controlled by Heos for CO2 and propane.
To help manufacturers avoid a long R&D process, CAREL can provide full condensing units for semi plug in cabinets using CO2 in subcritical conditions, called HeosBox, while for those that prefer to build their own finished equipment, Heos components for both CO2 and propane.
Waterloop systems are very convenient for stores up to a certain size, as the refrigerant charge can be reduced by up to 80% and the risk of leakages is drastically lower than with the traditional centralised approach.
Moreover, the ratification of IEC 60335-2-89 as an EN standard has increased the propane charge limit to 500 g instead of 150 g per circuit, opening the possibility to reduce the number of circuits needed to deliver the cooling capacity for a single cabinet. This will stimulate the demand for devices able to modulate capacity according to cooling demand, bringing more efficient installations.
As regards centralised systems, one of the main worries is being able to easily coordinate and maximise the performance of the rack with that of the cabinets: CAREL is promoting controllers for centralised CO2 systems that combine condensing units and cabinets in a system featuring a high level of connectivity, facilitating commissioning and maintenance using a dedicated app.
Work in the equipment manufacturer’s technical departments and production lines is also made easier, thanks to specific software for parameter setting and configuration. In particular, the uRack, MPXone and MPXzero electronic controllers share the same modern software environment and app, creating an easy-to-integrate ecosystem.
When adopting propane, one worry is flammability: the latest MPX controllers, such as MPXone and MPXzero, as well as the iJ range, are FMEA compliant, meaning they are certified for use with all A3 refrigerants.
Centralised systems using CO2 can be equipped or retrofitted with Chillbooster, to increase efficiency and respond to heat waves, or to compensate for the undersized gas cooler in the original installation.
Finally, if for whatever reason a customer prefers to use a synthetic refrigerant, they need to know that CAREL supplies the same control devices for those applications, as well as leakage detectors to prevent the waste of expensive and environmentally-harmful refrigerants.