Future refrigerant choice will be reduced to HFOs, carbon dioxide, ammonia and hydrocarbons, according to Michael Bellstedt, managing director of consulting firm Minus40.
Outlining the impact of refrigerant choice on the total cost of a project, Bellstedt said new low GWP replacements will be more toxic, flammable or both.
“Systems will need to be designed for minimum charge and technicians will require much better training. Also, carbon pricing will return, in some form, in the future,” he said.
“HFCs are being phased down at a time when there is an increasing need for refrigeration, demand is not decreasing.”
Bellstedt said every technology requires a business case but it must look at the entire financial model, not just capital costs.
“There is a lot to consider from energy efficiency, levies and compliance costs to issues like redundancy, longevity, reliability and serviceability,” he said.
“I recently saw an ammonia-based system that was in mint condition and was 46 years old.”
Bellstedt then listed other factors such as air-cooled versus evaporative condensers, DX versus liquid recirculation, commercial versus industrial, semi-hermetic versus open drive, steel versus copper.
“Steel systems always last longer and while copper works harder there is greater leakage,” he said, adding that open drive is more efficient than semi-hermetic.
“Annual energy costs can vary by a factor of two or three based on refrigerant choice.
“This is because refrigerant choice will dictate your operational costs.”
Bellstedt used a financial modelling graph to show the cost differences between an R22 system and ammonia plant.
He also used case studies including an upgrade at fruit supplier Radevski Coolstores, which achieved 40 per cent energy savings by installing an ammonia-based system to service its 16 cool rooms.
Last month, Bellstedt completed a project at the Ryan Meat Company, which had R134a heat pumps, a wide range of R22 heat pumps and R408a condensing units.
“DX evaporators and single compressor units were replaced with open drive machines. We used liquid recirculation and stainless steel evaporator coils and removed all HFCs and HCFCs,” he said, adding that heat recovery is being used to meet 80 per cent of the company’s hot water requirements.