Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)

Department / School

Mechanical Engineering


Municipal water mains have been used as the heat source/sink for electric water-source heat pumps. Called municipal water main source heat pumps (MWMSHPs), these systems have the advantage of a heat source/sink with temperatures that vary over a much narrower annual range than the outdoor air. This paper addresses the thermodynamic feasibility of such a system at a specific site and the potential effects that it would have on the municipal water system. The building chosen for analysis was the Sioux Falls, SD, City Hall. The flow rate and temperature of the municipal water in the distribution system was monitored at a point near this site for a period of ten months. The temperature data represented entering water temperatures (EWTs) for the heat pumps. An analysis was performed to determine the water flow rates required by the MWMSHPs and the temperature of the water leaving the system.

The analysis showed that during a typical peak heating season the minimum leaving water temperature (LWT) would reach 32°F, using the EWT's from the actual measurements. During a typical peak period in the cooling season the maximum LWT would approach 84°F. Because of the dangers of freezing, the system proposed would not be able to operate without a source of supplemental heat during periods of maximum heating demand. In addition, the EWTs supplied by the municipal water at this location would cause the heat pumps to operate outside the envelope of peak performance during a significant portion of the year.

Library of Congress Subject Headings

Heating -- South Dakota --Sioux Falls


Heat pumps



Number of Pages



South Dakota State University



Rights Statement

In Copyright