Table 1: Heat exchanger temperatures during operation.

Average temperature12 noon3 pm6 pm

Inlet (°C) 32.432.633.4
Outlet (°C)33.534.834.9
Heat extraction factor/unit time1.1°C2.2°C1.5°C

Inlet temperature of water was measured at the entry valve point just before this entered building. Outlet temperature was measured at the point of exit immediately after leaving the building (please see Figures 2(a) and 2(b)).