Questions_round_4.pdf

Questions round 4, Week Ending 12 October 2019 Solicitation: N68335-19-R-0202

Questions and answers:

Question 1: Please provide the ship’s chilled water temperature and flow rate that will be supplied to the ECW-50. Prior answers to this same question pointed to another document, DOD-STD-1399-532, as a guideline for the ship’s chilled water. The newest revision of this document, dated February 1990, does not specify a temperature or range of temperatures. The previous revision of this document, dated May 1978, states in section 5.2.2 that “the temperature of the cooling water provided to the electronic equipment inlet connections will not be greater than 40°C (105°F) on surface ships”. With 105°F chilled water, a liquid-to-liquid chiller will not allow the ECW supply to be in the range of 41°F and 59°F. We suspect that the ship’s chilled water is actually much lower than 105°F, but we’ll need to know what it is as it will directly affect the chillers heat exchanger size and chiller configuration. If the water is in fact 105°F, a liquid-to-refrigerant-to-liquid chiller configuration may be considered, which will use a vapor cycle to reject heat to the ships chilled water.

Government Response: While we are being told that the ship regularly provides chilled water at temperatures lower that the specified maximum below, we have not been able to obtain documented values at this time. Please defer to the older values. We expect them to be lower but can’t officially qualify now.