hat is the assumptions or reasons that help to make the error between hand calculation and hysus value is small for compressor, pump, heat exchanger

please written solution by hand and how can com h6 and s6 when  T turbine inlet = 130 C  , P heat exchanger = 20 bar , P condenser = 5 bar    , Tw . cond out = 25 C       Tw cond in = 17.5 C  efficiencies compressor = 67.5    efficiencies turbine = 78          m. refrig =0.4 kg/s

Q.4 (a) Explain the steps involved in representing the natural and mechanically driven air flows within a building using the nodal network method.

a) In a concentric-pipe heat exchanger, one of the fluids is a condensing vapour and the other is the coolant. Sketch the variation in fluld temperatures of two fluids as they flow through the heat exchanger. Indicate clearly the Inlet and outlet of the coolant and its direction of flow. b) For the case outlined in a) above, the heat-transfer rate, Q, between the two fluids is given by Q =U. Ą ATLI where U, Is the overall heat-transfer coefficient for the heat exchanger, based on the outside surface area of the inner tubo, A, Is the outside surface area of the inner tube and AT Is the relevant temperaturo difference given by ATLM = (T₂-T₁) Tv-T₁ In where subscript v refers to the condensing vapour and subscripts 1 and 2 refer to the Inlet and outlet temperatures respectively of the coolant. 1) State the assumptions used to arrive at the above equation. Explain why the "log-moan" temperature difference above is a more appropriate temperature different for heat exchangers than, say, the…