Archive for: Application

When dealing with high percentage outside air systems, it comes down to matching the capacity of the compressor(s) to the varied entering air conditions. The APR Control’s ability to load match will keep the compressor active despite the varied entering air conditions. This load matching ability of an APR Control enhanced system will keep discharge air temperature consistent, the discharge air below desired space dew point, as well as preventing compressor abuse from rapid cycling or floodback. These are the conditions that historically have plagued DX systems in high percentage outdoor air applications.

High altitude has lower air density, resulting in inadequate heat transfer at the evaporator coil. This leads to low suction pressure and improves the likelihood of coil icing. The APR Control will maintain suction pressure above a minimum psi as set on the APR Control (118 psi/40°SST).

Liquid slugging can result in damage to the compressor! The APR Control prevents or eliminates liquid slugging or compressor floodback from occurring by varies the cooling capacity of the evaporator coil by modulating refrigerant flow. During low load or non-design day conditions, when floodback or slugging is likely to occur, the APR Control will only allow enough refrigerant into the coil that can be fully evaporated.

During mechanical failures, like a broken TXV or loose fan belt, the APR Control diverts vapor into the suction line so that liquid refrigerant never reaches the compressor!

Undersized ductwork will lead to reduced airflow across the evaporator coil resulting in an extreme suction pressure drop. The APR reduces refrigerant flow to eliminate the chance of coil freezing as a result of low evaporator temperature. The APR Control will protect the refrigeration circuit from ultimately failing. In some situations, correcting the ductwork can be unfeasible even though it will provide a better/correct system. The APR Control will protect the circuit and allow the unit to function within the duct design limitations.

The APR Control can protect against the problems related to clogged filters, which will likely cause airflow across the evaporator coil to be reduced causing a drop in suction pressure which will eventually result in coil frosting. The APR will maintain suction pressure by modulating refrigerant flow reducing capacity at the evaporator.