Question

Question 4 Page 15 It is required to 125 marks] design a cold storage for storing vegetables with the following available data Outside design conditions 36°C DBT. 28 C WBT Inside design conditions T2 19°C DBT, 60% RH Infiltrated air 180 mhr V ms-7.83 kg/s Fresh air supplied from outside 4500 mhr Total mass of air supplied to the room Sensible heat gain through glass SH,5.5AW Sensible heat gain through walls and roof H 10.8 kW Ihr KJ Sensible heat gain per person HS = 240 KIr ざ20 200 KJ/hr 2 Latent heat gain per person LH Latent heat gain due to evaporation of water LH2 from vegetables 23.13 KW Sensible heat gain from the equipment Hy 3.1 KW = 20 Number of persons e.F =0.2 Bypass factor of cooling coil 6 C-tcc Apparent dew point temperature of the cooling coil Supply air condition (Temperature of air entering the room)- 16 C DBT If air-conditioning is achieved by passing air through the cooling coil and then the heating coil as shown in Figure Q(4) Calculate: [6 marks] Room Sensible Heat Factor i. [4 marks] The amount of recirculated air ii. [5 marks] State of the air after passing through the cooling coil ii. [5 marks] Capacity of the cooling coil iv. [5 marks] Capacity of the heating coil v. 2 State 2 Room DBT-19 C State 1: DBT 36 C WBT= 28 C RH 60% 4 3 Heating coil Cooling Coil Mixing Figure Q(4): Air-conditioning system. 2.

Answer 1

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Speeific volume ar sta^' Og04 m of air 4S mses Df nfiteráted ajr at point 1 2 V 0.904 (MA-h.115(5-) 3484 S125 ki1h SH)nfilatd air 0967 kw kalw) (Ikw 3660 199 I (10-59 LHinfiltate air 172 56 ko h 27146 Kkw ster 3: To띠 Sensi니a het RSH) totl atont heat(RLH Pargon air Enate tQM)person 23.1371 3640 -8 S 31t09679 259557ku Scaoths CamScahner

27012 Room sensible Heat factor RSHRLH 21.T012+255S7 RSHF 45536 An Hr ameuofReciralakedair - 9 Step. 4 RSHF O45s on Sengj&k heat factor Seale Ag pojnh a ana ointh 'pobt o maree DBT s0RH' >Pun Point doasa rprallal ne ab' Point5 Fntasasthingy Ah Vereal Lfne 16 s DBT at Gne Athis line 2-^)e knsum Point 5 Represent ha Comdlitie far sishcometic chart ls(4camy to queston 7.83 Ma 4560 4977 97 MF 382 mus sf Recireulateol air ma-M 793 382 MRecirulat afY "Ans . 447 7.83 OFRearelated air Cs Scanned with CamScanner

SAate Df he afy After dhaosha Pancingngt Reoirculatest n mieesl wh 17-6 at Pein 2 dfair atposnt L 2-3 Lat C-2)x17 2 22 e k ADp 3PF r ADp O 2 22 961. RH Ans 92 C er dv Capaeit f oling caie Ch3-h4) ma (s95-29) 1CHtB6 Scanned m CS CamScanner

Capmity nf hoaring C Capcy of heatgot cai -mahs-h4) 27 7-23 28.7 2(r Kuo 58 725kw CS Scanned with CamScanner