A chiller plant design consists of many pieces of HVAC equipment that are all interconnected by piping to form a chiller plant. This article will look at a water cooled chiller plant design.Do you want to learn more? click reference
The major parts of a water cooled chiller are the compressors, the evaporator heat exchanger (piping circuit #1) and the condenser heat exchanger (piping circuit #2). There are two separate piping circuits in a chiller plant design.
A chiller produces cold water that is typically circulated (pumped) to cooling coils that are inside air conditioning units. This is called the chilled water piping circuit, circuit #1.
The air conditioning unit fan takes air from a room and blows this air across the cooling coil to produce colder air and then circulates this colder air through a duct system to cool the room.
Once the cold water from the chiller cools the air, it becomes warmer, and it must be circulated back to the chiller so that it can become cooler again.
A chiller uses a refrigerant to cool the water, but once it cools the water the refrigerant becomes warmer and it rejects its heat to the cooling tower (or condenser water) piping circuit, circuit #2, so that the entire process can start over.
The basic design consists of a chiller or multiple chillers, chiller water pumps for the chilled water piping circuit, a cooling tower or towers and cooling tower pumps for the cooling tower water piping circuit.
In a water cooled chiller plant design, there is a cooling tower which is considered a heat rejection device and it takes the unwanted heat from the chiller, by circulating water through the chiller and then takes this warmer water and rejects this heat to the tower. The tower then takes the heat from the water and rejects this heat into the atmosphere. This is the second piping circuit and is called the condenser water circuit.
There are many different types of chillers that must be considered in a chiller plant design. The difference is the type of compressors and the difference in efficiencies in each type. There are scroll type compressors, reciprocating type, screw type, centrifugal type and there are chillers that do not use compressors such as steam absorption type chillers.
In a chiller plant design the chiller is selected based upon the amount of tons of cooling that it can produce. A ton of cooling is equal to 12,000btuh. So a 20 ton chiller has a 240,000btuh cooling capacity. The chiller cooling capacity must be equal to or greater than the cooling requirements of the building at peak load which occurs during the summer.