Engineering Design

Hi all
I need following calculations done on a project I am working on
We have designed the heating system as in the drawing. It contains four radiators (R1, R2, R3 & R4), a water heater and one water pump. Each radiator requires 200 kg/hr flow and all pipe have inner diameter of 12mm and outer diameter of 15mm
Q1- the heating system shown in figure below consists of four radiators (R1, R2, R3, R4), a water heater,
and one water pump. Each radiator requires flow rate of 200 kg/h. All pipes have inner diameter of 12 mm,
and outer diameter of 15 mm.
We have to calculate a) total pressure drop in the system and electrical power required for pump at 80% efficiency, b)total heat loss from water pipes assuming average temp of 80C for hot water. Also if all pipes be covered with a 6mm thick insulation layer (conductivity=0.03 W/mK) , how much percentage reduction in heat loss would be achieved
c) if the cold water leaving the radiator is in thermal equilibrium with air, we have to estimate the total heat required (average values can be used), d) we have to calculate annual natural gas price if it is sold at 20 cent/m3 and considering 70%efficiency of water heater