Supermarkets: carbon dioxide refrigeration weakens in heat waves

Carbon dioxide refrigeration loses efficiency in heat waves

What happens. Many stores have changed to central refrigeration with carbon dioxide as the refrigerant, because natural refrigerants are the direction the rules and the funding point to. In hot weather these systems run at high pressure, the gas cooler cannot reject the heat, and the system works far less efficiently or trips.

What it costs. Summer power bills rise exactly when the cabinets need the most cooling, and a trip on a hot weekend puts chilled goods at risk. Funding programmes for natural-refrigerant systems favour this technology, so many stores are committed to it (Umweltbundesamt).

Why the usual fix fails. Parallel compression and ejectors raise the efficiency, but they come with their own control settings. Transcritical systems are engineered for the climate of their region, and beyond that design point they can shut down on high discharge pressure (ESM Magazine).

How a fixed-price remote diagnosis checks it. From your refrigeration logs (pressures, temperatures, compressor and ejector states, power) and the outdoor temperature I check how the system behaves on hot days and where a different high-pressure setpoint or ejector control would help. The fixed-price remote diagnosis tells you whether predictive control of the high pressure is worth it, and what it would take on your systems.

Background: Economic predictive control