Buying tips—walk-in refrigeration

What should you consider when buying a commercial walk-in refrigerator or freezer?

Buy the right size unit.
Think about how much space is available in your kitchen, and what capacity your operation requires.

Look for a model with a remote compressor/motor condenser system.
These are more expensive to install and maintain, but they add less to indoor cooling costs and noise pollution.

Choose high-efficiency components.
By incrementally and independently reducing the load on the compressor, a high-efficiency refrigeration compressor, evaporator fan motor and condenser fan motor can each improve system energy efficiency by five to 10 percent.

Opt for energy-efficient demand-defrost controls.
This feature allows you to initiate defrost cycles in a variety of ways, such as measuring temperature drop, frost accumulation or humidity levels. All of these methods are more effective than using a simple timer to initiate defrosting, and can improve energy efficiency by up to six percent.

Select a model with anti-sweat heater controls.
Anti-sweat heaters keep external display doors free of condensation in high humidity conditions. Anti-sweat heater controls that sense humidity can be set to turn off heat in drier weather and can improve system energy efficiency by two to four percent.

Buy or retrofit a unit with floating head pressure controls.
In outdoor air-cooled condensers, these controls take advantage of low air temperatures, allowing the head pressure to vary with outdoor conditions. This reduces compressor load, extending the compressor’s life and reducing energy use by three to 10 percent.

Explore options for sub-cooling the liquid refrigerant.
Further cooling the liquid refrigerant lowers the temperature of the evaporator, substantially increasing the refrigeration system’s cooling capacity and overall efficiency. This can be done naturally, with an oversized condenser or mechanically, either with a remote cooling system or by running a refrigerant line from a central system. 

Ask about an evaporative condenser.
A unit using an air-cooled condenser can be equipped with a moistened filter to cool ambient air as it enters the condenser. This increases the cooling condenser capacity and cools the liquid refrigerant, which reduces the compressor load. An evaporative condenser can reduce energy use by three to nine percent.

Use a liquid pressure amplifier.
This small refrigerant pump raises the liquid line pressure. This reduces capacity loss at low head pressure, improving efficiency and ensuring lubricant circulation through the compressor. A liquid pressure amplifier can reduce energy use by as much as 20 percent and, with air-cooled condensers, efficiency gains increase as outside temperatures drop.

Ask about heat recovery.
The operating cost of a walk-in refrigerator or freezer can be partially offset by recovering heat from the refrigeration system for use in water heating and space heating. Ask an HVAC professional whether your unit is suitable for heat recovery.