(c) An existing radiator installed in a room has a heat output of 3.0 kW with low temperature hot water flow and return temperatures of 80 "C and 70 "C respectively. The heat loss of the room changes when a new building occupier changes the layout of partitions in the building. This reduces the size of the room, the external wall area and the winter heat loss to only 2.5 k W. The radiator is to be replaced with a smaller unit giving a heat output of 2.5 kW. The mass flowrate of low temperature hot water through the new radiator will be the same. Calculate what the new temperature difference between the low temperature hot water flow and return will be with the new radiator under design conditions