Hydrocarbons like propane (R290), propylene (R1270) and/or isobutane (R600a) are a feasible choice for applications in any temperature range, especially in supermarket applications where integrated systems can show great efficiency and reduce costs, according to Joachim Schadt, General Manager at German hydrocarbon chiller manufacturer Secon.
He spoke on the “Basic selection criteria for natural refrigerants” during the Day 2 “Planning and Procurement” session of the online Green Cooling Summit. The Summit took place September 13–14 and was jointly organized by the German Environment Agency (UBA) and GIZ Proklima on behalf of the German Federal Ministry for the Environment, Nature Conservation, Nuclear Safety and Consumer Protection (BMUV) and the German Federal Ministry for Economic Cooperation and Development (BMZ).
From process cooling to low-temperature applications and heat pumps, there is a natural refrigerant option for every temperature range, according to Schadt, who shared a table comparing the feasibility of common natural refrigerants. “Almost all applications can already be covered efficiently, safely and economically with natural refrigerants,” said Schadt.
Hydrocarbons were considered highly feasible in all temperature ranges except low-temperature applications (-15 to -30°C/5 to -22°F), where its use is possible but not necessarily the best choice.
Hydrocarbons score high in terms of efficiency and are suitable to use in ambient temperatures up to 50°C (122°F). Purchase and maintenance costs are rated medium.
Heat recovery important for supermarkets
There are great opportunities for natural refrigerants in supermarket applications, according to Schadt. He noted that particularly R290 waterloop systems are becoming popular in discount stores in Europe.
In supermarket applications, it is becoming more common to also use natural refrigerants to serve the heating and air-conditioning loads – not just refrigeration. For example, R290 chillers (either water- or air-cooled) are very suitable for this application, according to Schadt. In addition, all-in-one R290 or CO2 (R744) integrated systems, including heat recovery, can realize great efficiency gains, he said.
“It is obvious that heat recovery is the best solution for covering your heating demand,” said Schadt. “You should cover most of your heating demand by heat recovery. Discount supermarkets can cover around 80% of their heating demand by the heat recovery of the refrigeration system.”
Schadt also highlighted that modular systems should be considered for supermarkets as these are flexible and can be easily adapted for all heating and cooling needs.
“Almost all applications can already be covered efficiently, safely and economically with natural refrigerants.”
Joachim Schadt, Secon
Technical recommendations
Schadt shared the following planning and procurement considerations for propane systems:
- Optimize the system temperatures for increased efficiency.
- Plan enough space for cooling systems; make sure the machine room is big enough to avoid limitations.
- Avoid using drinking water in the system for evaporative condensers or adiabatic gas/dry coolers.
- During the planning process, consider the redundancy required for the project and/or possible future extensions.
- Do a risk analysis and request a safety concept and installation instructions from the supplier. (This should be readily available.)
- Specify not only capacities and temperature levels, but also get binding values for delta T for the evaporator and condenser.
- Ask about system limitations and requirements upfront.
Secon recently received the Natural Refrigerants Label from ATMOsphere.
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