SL-08-010 -- Hot Water Distribution System Piping Heat Loss Factors, Both In Air and Buried - Phase II Test Results PDF

This paper describes results of recent laboratory tests on rolled copper (CU) hot water distribution system piping and compares them to previous test results on rigid CU and PEXAluminum - PEX piping in air. It also describes heat loss results for both rigid and rolled CU buried in damp sand. These tests allowed calculation of measured piping heat loss (UA) factors under a variety of different temperature and flow conditions, with various insulation levels. This piping UA information can be used to estimate piping heat loss and steady-state temperature drop under any desired temperature and flow conditions. The UA data additionally can be used to determine piping cooldown rates after flow has ceased. Piping heat loss data is one critical part of the information necessary to accurately estimate total energy losses associated with piping systems. These energy loss effects extend beyond just energy loss from the pipe itself and include, for example, increases in tank heat loss caused by the need to set temperatures higher to overcome temperature drop of water flowing through the pipe.

Units: Dual