What is primary and secondary pump in HVAC?
The primary loop uses a constant speed pump to circulate the working fluid (water). The secondary loop uses a variable speed pump to manipulate the flow of the fluid such that the cooling coil demand is satisfied. The above mentioned pumps are considered as a primary/secondary pumping pair.
How does primary secondary pumping work?
Primary/secondary pumping is simple in theory and practice. Its operation is based on this basic rule: When two circuits are interconnected, flow in one will not cause flow in the other if the pressure drop in the piping common to both is eliminated.
What is primary and secondary pump in chiller?
Constant speed pumps drive the flow through the primary (chiller or boiler) loop. A separate secondary pump delivers variable flow to the secondary loop and two-way valves are applied to control flow through each zone.
What are the advantages of primary secondary systems?
The advantages of a primary-secondary system are: Simplified controls. Constant flow through the chiller (better chiller performance) Smaller pump motor sizes.
What is the function of secondary pump?
The secondary pump has to draw that 10 GPM from its own flow, creating backwards flow across the common piping when both pumps are on. This could be useful where a two-temperature system is needed. Return and supply water can be blended to have a two-temperature system without using a three-way valve.
What is secondary system?
The steam generator tubes, steam turbine, condenser, and associated pipes, pumps, and heaters used to convert the heat energy of the reactor coolant system into mechanical energy for electrical generation. Most commonly used in reference to pressurized water reactors.
What is secondary condenser?
Secondary condenser water loops are used to transfer heat away from chillers and into cooling tower water, thereby providing an intermediary step between the chiller and cooling tower water.
What is a decoupler in chilled water system?
The decoupler allows excess primary water to flow back to the return side of the chillers, ensuring constant flow. Water flows rebalance so that the rate of flow in the primary loop equals or exceeds the rate of flow in the secondary loop.
What is primary pump in chiller?
Variable flow primary pumping saves pump energy by reducing water flow through the system with VFD controlled pumps during part load operation. With less water flowing through the chiller, variable flow primary pumping also saves compressor energy with variable capacity compressors.
How does a chilled water pump work?
The chilled water pump circulates return chilled water from the air handling units & fan coil units back to the chiller. The chiller then cools the chilled water and the chilled water is then supplied back to the air handling units and fan coil units. The chilled water pump circulates chilled water through the system.
What is a decoupler line?
The answer is through DECOUPLER LINE which bypasses the secondary loop in the system. The doupler line is a bypass line that is connected between the suction points of primary pumps and secondary pumps. Please note that chiller outlet point and secondary suction point are one and the same.
What is primary and secondary circuit?
The primary circuit is between the battery and the ignition coil. The secondary circuit is between the ignition coil and the spark plug. A secondary ignition circuit consists of three components and is the basis for newer variations of the ignition system.
How does a primary and secondary pump system work?
They operate as if they are two independent systems. Depending on the flow rates of the primary and secondary pumps, water can move forward, backwards, or not at all! If both pumps are sized for a flow rate of 10 GPM, when the primary pump is on and the secondary pump is off,…
Are there any secondary pumps in a boiler?
In this simple design, there is only one set of pumps (chiller or boiler pumps) creating flow for the entire system. As you can see in Figure 1, there is still a common pipe between the chiller pumps and the system distribution, but there are no secondary pumps.
What does primary mean in a HVAC system?
This refers to particular parts of the system which have a unique purpose. The Primary side of the heating or cooling circuit contains the boilers or chillers as well as the primary pumps.
What makes up the secondary circuit in a HVAC system?
In this circuit the boilers or chillers heat or cool the water which is circulated around by the primary pumps in a continuous loop between the chiller or boiler and the low loss header. The secondary side of the system contains any of the plant items which transfer thermal energy into the rooms or equipment within the building.
