跳至主要内容

Determining Pump Head: A Guide to Optimal Water Pump Performance - Hstarschiller.com

 

1.Components of Chilled Water Pump Head:


Evaporator water resistance of the refrigeration unit: typically 5-7m water column (refer to product samples).
Water resistance of end devices (air handling units, fan coils): usually 5-7m water column (refer to product samples).
Resistance of components such as return water filters, two-way control valves: generally 3-5m water column.
Water resistance of headers and manifolds: typically 3m water column.
Friction and local resistance losses along the refrigeration system piping: typically 7-10m water column.
In summary, the pump head for chilled water is in the range of 26-35m water column, usually around 32-36m water column. Note: Pump head calculation depends on specific refrigeration system conditions; avoid blindly applying empirical values.
Chilled water pump head components

2.Components of Cooling Water Pump Head:


Condenser water resistance of the refrigeration unit: generally 5-7m water column (refer to product samples).
Water pressure at cooling tower spray nozzles: typically 2-3m water column.
Height difference from the water pan to nozzles in an open cooling tower: usually 2-3m water column.
Resistance of components such as return water filters, two-way control valves: generally 3-5m water column.
Friction and local resistance losses along the refrigeration system piping: typically 5-8m water column.
In summary, the pump head for cooling water is in the range of 17-26m water column, usually around 21-25m water column.
Cooling water pump head analysis

3.Make-up Water Pump Head:

The head includes the distance from the fixed pressure point to the highest point, resistance at the pump's suction and discharge ends, and a surplus head of 3-5m water column.
Make-up water pump head calculation

Example:

For a 100m tall building with water-cooled screw units, estimate the required head for the chilled water pump in a closed air conditioning water system.

Answer:

Evaporator resistance: 60kPa (6m water column).
Piping resistance: 185kPa (18.5m water column).
End device resistance: 45kPa (4.5m water column).
Valve and filter resistance: 40kPa (4.0m water column).
Total system resistance: 330kPa (33m water column).
Pump head: Taking a 15% safety factor, H = 33m * 1.15 = 37.95m.
Based on the estimation, one can grasp the pressure loss range for water systems in similar-sized buildings.
H.Stars Chilled water pump
标签：

评论

发表评论

此博客中的热门博文

Avoid Downtime, Cut Costs: Smart Maintenance for Smarter Chillers

  Screw water-cooled chillers   typically operate around 3,000 hours per year, depending on China's climate and geographical conditions. Regular and scientific maintenance is crucial to ensure long-term, reliable operation, extend the lifespan, and reduce operating costs. Maintenance and Upkeep Preventive maintenance during operation and inspection involves creating annual and monthly maintenance plans based on actual operating conditions. Shutdown Procedures In winter, clean and dry the unit. Open the drain valve to empty the  shell-and-tube heat exchanger  to avoid freezing. The shutdown sequence is: chiller off - cooling tower fan off - cooling water pump off - chilled water pump off. Special attention to anti-freezing: 1. Drain the evaporator and condenser if the unit is outdoors below 0°C during standby. 2. Interlock the water flow switch with the unit to prevent freezing when the chilled water flow switch malfunctions. 3. Ensure water in the evaporator is flowi...
发表评论
阅读全文

What are the differences between air-cooled chillers and water-cooled chillers | Oumalchiller.com

  We all know that according to different heat dissipation methods, chillers can be divided into air-cooled chillers and water-cooled chillers. What is the difference between air-cooled chillers and water-cooled chillers? ​ 1. The  air-cooled chiller  uses copper tubes and aluminum fins to dissipate heat from the condenser. A fan is required to blow the outdoor air through the heat exchange fins and take away the heat of the condenser, so the air-cooled chiller does not need to be connected to the cooling tower. But compared with water-cooled chillers, under the same power, air-cooled chillers have larger equipment size and higher noise. The condenser of water-cooled chillers exchanges heat with the cooling water from the cooling tower through the heat exchanger. The excess waste heat will be transported to the cooling tower through the cooling water loop and released into the atmosphere, or enter the water-water heat exchanger or soil heat exchange coil for storage. Ther...
发表评论
阅读全文

What is difference between centrifugal chiller and screw chillers?

 Water Chillers are generally divided into the following categories: screw chillers, centrifugal chillers, water ring heat pump units, plate and tube evaporative condensing screw chillers, thermal storage air conditioners, etc. Screw chiller and centrifugal chiller are equipment that we often encounter. Below,  Oumal Refrigeration  will take you to understand the difference between centrifugal chiller and screw chiller? What is a  screw chiller ? The compressor adopts a screw type, hence the name screw chiller. The refrigerant coming out of the evaporator of the unit is a gas; after adiabatic compression by the compressor, it becomes a high-temperature and high-pressure state. The compressed gas refrigerant is isobarically cooled and condensed in the condenser. After condensation, it changes into liquid refrigerant, and then expands to low pressure through the throttle valve and becomes a gas-liquid mixture. The liquid refrigerant under low temperature and low pressu...
发表评论
阅读全文