Question

Problem: Feasibility Study of Recovering Waste Heat from Primary Process Cooling Water to Provide Heat for a Secondary Process Primary Process Cooling Water 100 F Secondary Process Requirements: Heat Supply Rate of 330,000 BTU/hr at 150 F Recovery System Heat Pump R134a Compressor Isentropic Efficiency: 76% Design Values Evaporator Coil Design Pressure: 160 psi Condenser Coil Design Pressure: 300 psi Deliverables Design Coil Temperatures (Evaporator and Condenser) - Confirm that these will be consistent with temperatures at the heat source and the process Compressor Power (BTU/hr, HP, and kW) Coel Of Performance / Compare to Maximum Theoretical COPhp e

Answer 1

SOLUTION: PAGEL Given daha , Cooling water available at 10 of for a's Drimony Process; used as treating requirement 9 330000.Btu/ho at 150 F 5 Secondary process using at R134a heat pump system Evaporator pressure : 160 Psi Condenser Pressure : 300 Pei Compre8807 ¿ceuropic Efficiency . 76.4 Ket us Assunce, R134a system will work with outlet saturated vapore and Cordersen Outlet saturated Kiquid Evaporator is Evaporator Temperature ab 160 Psi = 109.57 Condensen Temperature at 300 Pei = 156.9 F, as alater to be beated from coof to 150 f at Condenser → Values q Enthalpies at Condensen, Evaporator and Compressor from Properties table g R134a as follow Saturation Pressure, Enthalpy tiquid, Exthalpy Vapour Psi Btu/26 Btule6 Evaporator 160 48.519 117.18 Condenser 300 66.339 120.52 compressore illet 160 119.78 Compressor outlet 300 122.9

330000 X 540176 360o Heat added at Compressor COP hp = PAGE 2 ds Compressor i Centro Pic Efficiency : 76.74 > heat added during iCentro Pic Compression - 5.7210.76 = 7.53 B Beule6 Heat Supply rate is 330000 Btular, Condenser heat troisfer = 54.176 Btuleb > Refrigerant flow rate : Refrigerant flow rate = 1.692 16/ second = 12.74 Btu/ fecond * Compressor power requirement = 12.74 1.415 8 HP 13.4 KW Coef or performance / Compare to Mor Theoritical COPhp: Heat transfer at Cordlenser/ Heat added at compressor = 7.53 * 6091.26 360o AS I Btuls=20415 HP 2 Dhe =54.176 7.53 * Copap = 7.2 Man theoritical COP lip as per Candot Efficiency is COP Apman 15609 Ĉ 3. 3 (156.9-10905) COP he man =3.3 As man possible cop is a cop of beat Pump, the System may not work. So we redesign with lower Evaporator Pressure. for feasible design mou Possible COP must be always higher. //