Design a heat exchanger that can convey heat from a hot water source (H) to two cold water sinks (C1 and C2) by the use of a third transfer fluid (T). Thermal fluid T should transfer heat from H to C1 first and then from C1 to C2. There should not be any direct transfer of heat from H to C2 and C1 should be the only source of heat for C2. The distances between H-C1 and C1-C2 should be 30 cm.