Response_to_Questions_08_Feb_2019.pdf

QUESTIONS/ANSWERS

W913E5-19-R-0001

08 February 2019

Question One: What is the entering fluid temperature?

Answer:

In-put temperature, low temperature chiller: "In regard to the existing 17/25-ton chillers and proposed 30-ton replacement chiller, entering fluid temperature for the low temperature chillers should be assumed as DOW Norkool at a temperature range of -35 ℉ to 80 ℉, assuming either minor cooling to sustain temperature with low load at the bottom of the range, to beginning to draw down the tank in summer when it has equalized with external temperatures for the high end of the range."

In-put temperature, medium temperature chiller: "In regard to the existing 120-ton chillers and proposed 120 or two single 60-ton replacement chillers, entering fluid temperature for the medium temperature chillers should be assumed as DOW Norkool at a temperature range of 12 ℉ to 80 ℉, assuming either minor cooling to sustain temperature with low load at the bottom of the range, to beginning to draw down the tank in summer when it has equalized with external temperatures for the high end of the range."

Question Two: What are the flow rates in GPM?

Answer:

Flow rates into chillers: "Flow rates should be dictated by the required system cooling performance. Because a specification for the draw-down rates is based on a 3,000 gallon tank being cooled within a fixed period of time from a provided starting temperature to a desired end temperature, the flow rate should be selected to meet this requirement and to accommodate the piping sizes in the provided mechanical diagrams as well as the pump specifications referenced in the DOR. For the medium temperature loop, the current pumps are 240 gpm with 74 feet of head, with a separate set of pumps per chiller. For the low temperature loop, the current pumps are 141 gpm, with 55 feet of head, which supply both the 17 and 25-ton low temperature chillers.

Each chiller is supplied by two such pumps according to its specification (either medium or low) which are piped in parallel. Therefore, the flow rate to a low temperature chiller is two 141 gpm pumps in parallel; the flow rate to a 120-ton chiller is two 240 gpm pumps in parallel."