Equipment placement is an important consideration for the overall success of a walk-in cooler or freezer installation. The location of the condensing unit and evaporator must be evaluated thoroughly. Improper placement can lead to excessive installation costs as well as system performance issues.
Let’s discuss the location of an air-cooled condensing unit.
First, the location should be discussed with the customer. Be sure the customer is in agreement with the placement of the condensing unit. As retail space becomes more expensive, customers will want to take advantage of all their indoor space and may want the condensing unit located outdoors or in an indoor location that will not interfere with their business operations.
If the condensing unit is to be placed indoors, make sure the location has adequate ventilation. Low-temperature condensing units will require approximately 200 cfm per 1,000 Btuh, and medium-temperature units will require approximately 165 cfm per 1,000 Btuh. Always check with the condensing unit manufacturer for ventilation requirements as they may differ from these approximate values. Another consideration with air-cooled units located indoors is the heat they may add to the space. This additional heat may be objectionable to the equipment owner.
The alternative is to place it outdoors. When installing outdoors, there are several additional components that should be installed to the condensing unit. The condensing unit will need some means of keeping the high-side pressure above a minimum value during low outdoor temperatures. This is normally accomplished with either a fan cycling control or a head pressure controller. The system should use a pump-down method to control the operation of the condensing unit and a crankcase heater to help prevent refrigerant migration during the off-cycle. If installing a medium-temperature cooler, a defrost timer should be added to ensure that the evaporator defrosts properly. The outdoor unit should be covered to protect it from the outdoor environment.
One last consideration when installing either an indoor or outdoor condensing unit is to make sure the system can easily be serviced. Too often, service technicians encounter systems where the condensing unit is located in an area that is extremely difficult to access.
The installation of the evaporator coil is also vital to the proper operation of the entire system. There are several general guidelines that apply to most installations; however, it is always best to check with the manufacturer of the evaporator for specific instructions.
Here are some of the general guidelines when installing an evaporator in a walk-in:
- The air pattern of the evaporator must envelop the entire room. This is important in order to provide a more uniform temperature throughout the entire box. Do not install the coil where another product could potentially be stacked and block the airflow. Always allow for sufficient space between the rear and sides of the evaporator and the wall to permit free return air. Check with the manufacturer of the particular coil for exact minimum spacing requirements;
- Never install an evaporator above a door. Placing an evaporator above a door can cause the evaporator to draw warm, humid air through the coil each time the door is opened. This will cause the evaporator to frost up more quickly; and
- Do not install an evaporator in an area where it will interfere with the aisles or storage racks. This may cause a problem for the store owner, which could result in the evaporator needing to be relocated. The location of the evaporator should allow for easy storage and removal of the refrigerated product.
Proper equipment location on any installation will lead to a successful installation for both you and your customers.