When it comes time to select a pump, the pump head requirement will be determined by the most hydraulically remote circuit. You should select the lowest supply chilled water temperature. The pressure drop through this equipment at a specified flow rate must be provided by the manufacturer of the equipment. The chilled water pump schedule provides all the necessary design requirements to purchase the chilled water pump.
|Date Added:||9 September 2004|
|File Size:||46.82 Mb|
|Operating Systems:||Windows NT/2000/XP/2003/2003/7/8/10 MacOS 10/X|
|Price:||Free* [*Free Regsitration Required]|
The total dynamic head is found through the excel calculator. Often, much design consideration is given to the initial operation of these systems.
For example, the shape could be square, rounded, tapered and the pipe size change could be sharp or gradual. If this were not the case then we would need to perform multiple pipjng head loss calculations to determine the most hydraulically remote load in the system. First, we'll start with a baseline cooling coil, which represents the coil's performance at system start-up.
You should select the lowest supply chilled water temperature.
Using PIPE-FLO® to Design New HVAC Chill Water Systems - Engineered Software, Inc.
Data centers, data closets, edge and cloud computing, co-location facilities, and similar topics are among the fastest-changing in the industry. In this example the pipe sizes were calculated to achieve an average fluid velocity of 8 feet per second and the pipe sizes appear in Figures 1 and 2.
It is a great resource to get bite-sized educational pieces similar to the content featured in our seminars. The design and selection of a chilled water pump typically results in the completion of the chilled water pump schedule. In looking at the four circuits in Branch 1, the total head loss for each branch is different because of the distance the fluid must flow through the system.
Cooling Tower and Condenser Water Design Part 1: The Refrigeration Cycle —
Sum the losses for each circuit including the losses through the pipelines, air handlers, and the minimum required differential pressure across the control valve, along with the other components found in the circuit. For this reason, the calculator will highlight in red any Reynolds Number that is below the turbulent region. The method presented above will always ensure that the most hydraulically remote circuit is used in calculating the total head requirement for the pump.
Finding the Most Hydraulically Remote Circuit First, let's review how to calculate the pumping requirements for any circuit in an HVAC chilled water system, and then see if we can simplify the process to find the pumping requirements of the most hydraulically remote circuit.
The software will show the speed RPMefficiency, brake-horsepower BHP and horsepower HP for the various pump types that can meet the required flow rate and pressure drop. In this article, we will be using the piping system shown in Figure 1.
Since the piping system model created by PIPE-FLO has all the system connection information, there is no need to manually determine the pipelines and components in each circuit. Since all 16 circuits in our system are identical we will use this total in all future circuit calculations. There are various pipes available for use in the calculator but you can also add your own cyilled information.
Future-proofing a chilled-water system
This is to insure that once the pump is selected and the system built, there will be sufficient margin for proper operation. Remember that each circuit will have a total head loss needed to pass the circuits design flow rate.
Each pipe material and desig type within that pipe material have its own standard pipe sizes. This is why there is a control valve in each circuit.
Each of the four branch supply and return lines are identical. Lower waterside delta T is almost a natural part of a chilled-water system's aging process.
See store for calculator. In addition, the losses for the air handlers and control valves can be entered so the spreadsheet can add up the total losses for each item in the circuit. By modifying the coil-selection parameters, it's possible to simulate changing conditions at chilled-water coils.
While this may satisfy the immediate needs of the warm spaces, it also negatively impacts the chilled-water coil performance. The common return header for Branch 1 from the first floor to the main return header pipe B1R-1 is the next pipeline in the system and once again the flow rate in this pipe is gpm.
Remember, only items listed as hydraulically remote will be used to calculate the pressure drop for the chilled water pump. This not only streamlines the process, but it insures the correct information is consistently entered. The output for this equation is the pressure drop in units of feet head. However, understanding—and planning for—changes that occur as the system ages is critical to designing a chilled-water system that will operate properly for years to come.