Mid Review (3) PDF

Psychrometric Relations: h s 1.005 DBT W 250141.88 DBT kJlkgd if 0 loot DBT WBT DPT 4030 DBT 1235 DPT...

Psychrometric Relations: h s 1.005 DBT W 250141.88 DBT kJlkgd if 0 loot DBT WBT DPT 4030 DBT 1235 DPT 235 if 0 4030 no 1001 DBT NBT DPT DBT 1235 y if Definition P fromtables r G 100 ka Psat DBT T t is an It is not affected by the moisture present in it. MU Ws 0.622 Ma 91 l-S 11 pi WBT T 77 E v RI pl p Sst affected by moisturepresent in it 75 d Prs Pi 1.8 Pt t t Pr e PPT 2700 hm Pt PatPv Problemg given Pt DBT ob A 98 pthNBT M g. gn n Pi 1.8Pelt ty. W Pr Psat at DPT Pr 00221 E Esat 2700 Gable at DBT from tables GtableatWBT Prov i Prov Prov Prov Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791 Unit conversions MPa KPa L m Im Is hr Is Kw ton ref  r y ka an 91 l-S 77 E 75 d e hm ob A 98 M g. n. E Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791 Psychrometric Chart: y 4 85.3 0 501 r WBT ka PatmsPt 274 an ppg 91 l-S 77 E V 75 d V e hm 7 36 8 0.903 ob A 98 M g. n. E Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791  sensible.FI afent Q changes DBT changes W r y on chart horizontal line vertical line ka mass flow rate kgIs temperaturechange oc pair an s Madhhorizontal magma Q1 91 l-S Madh me vertical Mahfg AW 77 E enthalpy change kjlkg specifichumidity change kgH2o kg air air specific heat 1.0216 Kj kg K 75 d Cpm e water latent heat of vaporization hg 2501 Kj kg hm air volume flow rate Va Mav Mls Mw Ma Wz We ob A Ma at the Point where 98 Total heat transfer the volume is Qt given M g. Q n Q Qs QL Mathtotal. E Qs kw from balance Qt mass Q Z Ma in Ma out Qs Ma Maz ma for all processes except mixing Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791 Processes cooler cooling capacity Pre cooling using cooling coil at ADP DPT Qe Mach ha ha Malp T 12 heating using heating coil Qu ma ha y Macp T2 1 Heating capacity r cooling and dehumidification using cooling coil at ADP DPT ka Cooling Coil Qs Ma Cpm T T2 Qt Ma Chi ha 5 BPF an unit 19 5 Mw Ma Wi Wa SHF BPF T2 ADP Wa Wadi Qq T ADP W WADI ADP 91 l-S by chart at intersection point of process line with saturation line 77 E steam humidification DBT constant mw ma Wa Wi 75 d Adiabatic humidification e h constant WBT constant hm Mw Ma Wa Wi ob A humidifying 98 cooling humidifying humidifying Heating M g. f n heating. looting E cooling dehumidifying Heating dehumidifying dehumidifying Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791  r y ka ifrequired sensible heat factor an SAF Tr ADP 17 14 0.1154 App 40 14 91 l-S T 77 E 75 d e hm ob A 98 M g. n 2. E 212 ADP Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791  ADP known T 27 C 0 60 T2 16 C 02 90 Va 1000 MThr required Qe SHF ADP BPF Mw r y from chart h 61.7 solution kj kg W 0.0133 k.gr kgda J 0.87mlkgh2 s ka 42.2kjlkg Wz 0.0102kgw kgda an Y 1149.43 kg hrs 0.3193 kgIs Ma 17 91 l-S 77 E 3600 0.3193 6 kN 1.78 ton ref Qe Ma h ha 61.7 42.2 63.3 75 d e hm ob A hi 98 M g. t n U2. E is ADP V Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791 T 27 C 0 60 12 16 c 02 904 V 1000m hr SHF ADP BPF 4 0 0132 Ma 18 Mw W2 0 0702 7 Qc Ma Math ha 0.319 60.8 42.2 5 w Qc 1.695 ton ref ma 0.39kg SHF Q Q Qs Ma Cp T 72 3.579 KW 3 SHF 9 0.603 ADP 13.25 BPF T.IE 0. Mw Ma W W2 9.57 10 4 Kg s  QI SHE Qt Q 6.226 kW r y Q Ma Cpm T T2 0.3193 1.0216 27 16 3.588 KW ka SHF 0.576 538 an from chart 91 l-S ADP 13.3 C F 1 BPF 0.083 77 E BPF Ta ADP 16 13.3 0.197 75 d T App 27 13.3 e hm Mw Ma Wi Wz s 0.3193 0.0133 0.0102 9.9 15 kg s ob A 98 9.9 10 LIS M g. n. E Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791  anteatingcapacitym known T 12 C 0 75 I 22 C 03 60 Va 200 m min r y Ps 2 bar Xa 0.96 saturated liquid ka required steam Mn Mw an my solution Wand a 91 l-S from chart h 28.8 kj kg has43 47.6 kgkg 77 E 83 0.85 m kg W Nz 0.0066 kgwlkgda.ws 0 010 kgwlkgda 75 d e hm ob A 98 M g. 42 h3 n. E hi Ws Wi Wz 751 Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791  235.29 Kg Min Ma Y 235.29 kg min 60 ma 3.92 Kg 3 i On Ma cha h mn ha hb r y from table at P 2 bar 100 200 kPa ka hb he 504.71 kj kg hfg 2201.6 kj kg an i ha hf Xahfg 504.71 0.96 2201.6 2618.246 kj kg from 91 l-S Qn 235.29 47.6 28.8 4423.53 60 kj min 73.73kW 77 E 73.73 My 2618.246 504.71 3600 125.6 kg hr 75 d My 0.0349 kg 5 e b Mw Ma Wz Wz 235.29 0.010 0.0066 0.8 kgmin 60 hm i Mw 48 kg hr ob A 98 M g. n. E Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791  Finalcondition 3 9 1 Mw Malwa Ml Qc Malha h3 r y known T 38 C 0 20 Tz 220C 03 60 Va s 500 m3 min ka required Mw Qu Ms D Qe an solution for adiabatichumidifier from chart 91 l-S V 0.89 MYkg W s 0.0082 kgw kgda hi h2 59.7 kj1kg 77 E Wz Wz 0.0097 kgw kgda h 3 46.8 Kj kg 75 d e hm ob A hi hz 98 M g. hz n. E WasV3 I WI Contact us: N 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791  5 9.36 kgIs Mas Vy 8 56,8kg min Mw Ma Wz W s 9.36 0.0097 0.0082 0.01404 kgIs Qc MaCha hz 9.36 59.7 46.8 1203.754 kW 34.5 ton ref r y forsteamhumidifier ka from chart V 0.89 MYkg W s 0.0082 kgwlkg.da.hn 59.7kg kg an Wz Wz 0.0097 kgw kgda has 63.8 hj kg 43 46.8 kg kg Ms 91 l-S Ma Wz W s 9.36 0.0097 0.0082 0.01404 kgIs 3600 50.5kg h 77 E ez MaCha hz 9.36 83.8 46.8 759.12 kW 75 d DQe Qu Qu 159.12 120.74 e 38.38 kW hm DQ ob A h2 h 98 M g. h n. E WE W3 t Wi a Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791  salteatingcapacity r y known Tz 26 C 0 40 T 42 C WBT 29 C Vaz 500ms min ka ADP 10 C an equired Qe BPF Mh 91 l-S solution fromchart h 94.9 Kj kg ha 33 Kj kg Wi 0.0201 kgwlkgd 77 E Wz Wz 0.0084 kgwkgda h3 47.8 Kj kg V3 0.86 Milky 72 11.87 75 d h e hm ob A WI 98 M g. h3 n 2 ha. E Wz W3 Is to ADP V3 Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791  581.395 kg min 9.69 kgIs Mas Vy 50 60 Qe Math ha 9.69 94.9 33 599.8 KW y 35 r ka Qe 71.37 ton ref an BPF T2 ADP 11.8 10 0.06 T App 91 l-S 77 E 42 10 Qu Math ha 9.69 47.8 33 143.4 KW 75 d heatingcapacity if e required Qu Ma Mfg hm from table A 5 at Ps2 bar 100 200 kPa hey 2201.6ktkg ob A 143.4 My 2201.8 98 0.065 3600 234.5 kg h kgIs M g. my n if required The amount of water condensate.. E Mw Ma Wi Wa 9.69 0.0201 0.0084 0.1134 kgIs Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791  100 18 known T 50C 0 100 03 100 14 402,04 30 03 100 required T2 y Preheat 2s Adi hum reheat r Solution ka hmm from chart 72 402 RH an Q PH Malha hi 91 l-S Iep I MW Ma Ws w2 77 E Q RH ma hy hz 75 d e hm ob A ally sat 98 1001 M g. reheating 3 74 n I. E 3 4.883 I T2 Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791  r y ka known T 35 C 0 607 T2 20 C 02 90 V 300 m3 min an required Qe Vw 91 l-S solution a from chart 01 0.905 Mkg 77 E Mas 35 331.492 kg min 75 d e h hm ob A Y W 98 ha M g. 2 n WZ. E Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791  Qe Ma Chi ha from chart h 91 kjlkg ha 53.3kg kg Qe 331.492 91 53.3 12497.24 kflmin r y b Mw Ma Wi Wa ka from chart W Wz 0.013 Kgv kga 0.0216 kgv kga an Mw 331.492 0.0216 0.013 0.05 kgIs 91 l-S 60 i Vw Mwtw 77 E take Vw 0.001 Milky 0.001 5 10 5m31s A 1000 75 d Vw 0.05 e Vw 0.05 lit s hm ob A 98 M g. n. E Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791 known Ma 0.2 kg S T 45 C 0 10 Ma E 0.3 kgIs 72 25 C r y Wz 0 018 kg.ir kgda Ty 40 C ka required Ts 03 Oh I 04 an solution from energy balance for mixing process É Tz 91 l-S s Ma it Ma 272 Ma t Ma 2 0.2 45 0.2 0.3 0.3 25 33 C 77 E From chart 03 42 75 d e hm ob A 98 M g. n. E Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791 for heating Qu ma Cpm Tu Ts 0.2 0.5 Ma 3 Ma t Ma 2 0.3 kg s r y Qq 0.5 1.0216 40 33 3.5756 KW ka an from chart 04 28 91 l-S 77 E 75 d e hm ob A 98 M g. n. E Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791  r y ka an 91 l-S 77 E 75 d e hm ob A 98 M g. n. E Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791  0.408 0.52 Pups 100 0.893 52 Y ry 10 ka an 91 l-S 77 E 75 d e hm ob A 98 M g. n. E Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791  987 84 12 98.73 kPa Pts gghs 13600 9.81 701 at DBT 30 fromtables Psat 4.2469 kPa C at WBT 20 C fromtables Pi 2.3392 kPa ry 207 Pv Pi 1.8172ft t s 2.3392 1.8 98.73 130 2700 Pr 1.681 kPa 0 Pg É ka 0.3964100 0540 an 91 l-S 77 E 75 d e hm ob A 98 M g. n. E Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791  ry ka an 91 l-S DBT WBT DBT 77 E 75 d e hm ob A 98 M g. n. E DPT C WBT DBT Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791  ry ka an 91 l-S 77 E 75 d e hm ob A 98 987 84 12 13600 9.81 71 M g. Pt s gg h s Pt 98.73 kPa n fromtables Psat 4.2469 kPa. at DBT 30 C E at WBT 20 C fromtables Pi 2.3392 kPa 2 Pu Pi 1.8Pt t t l s 2.3392 1.8 98.73 130 2700 2700 a Pv 1.681 kPa O Pg É 0.396 100 407 14.941 15C ÉBÉ3_q 60.4 DPT 235 Contact us: 30 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791  ry ka an 91 l-S 77 E 75 d e 0.4 hm W 5 3 39 s Mma ob A 98 M g. n. E Ws 0.6221 0.622 03 7 W 0.241 Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791  ry ka an 91 l-S 77 E 75 d e hm tds BPF tdz.ly tdi tds ob A 98 M g. n. E or has 42 h has Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791  ry ka an 91 l-S 77 E 75 d e hm ob A 98 M g. n. E Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791  ry ka an 91 l-S 77 E 75 d e hm ob A 98 M g. n. E Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791 Air Washer: A. Cooling and dehumidification: t w < DPT. B. Adiabatic saturation: t w = WBT. y C. Cooling and humidification: DPT < t w < WBT. r D. Cooling and humidification: WBT < t w < DBT. ka E. Heating and humidification: t w > DBT. an 91 l-S 77 E 75 d e hm ob A 98 M g. n. E Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791  ry ka an 91 l-S 77 E 75 d e hm ob A 98 M g. n. E Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791  ry ka an a 91 l-S 77 E 75 d e hm ob A 98 M g. n. E Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791  Q ry ka an 91 l-S 77 E 75 d e hm ob A 98 M g. n. E i Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791  Inside & Outside Design Conditions r y ka an 91 l-S 77 E 75 d e hm ob A 98 M g. n. E Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791  r y ka an 91 l-S 77 E 75 d e hm ob A 98 M g. n. E Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791  19. Match the following: 1. A large precision laboratory-----...._ a. Variable air volume system 2. Perimeter zone of a building b. Constant air volume system 3. Simultaneous cooling and heating c. Multiple zone, single duct system 4. A large building complex ______..-, "-d. Dual duct system 20. Match the following: 1. Electronic chip ,manufacturing unit a. Window air conditioner 2. Interior room of an office ---- b. Package unit 3. A bedroom with a north facing wall c. All air syste:m 4. A medium sized restaurant ---- d. Split air conditioner Contact us: 66570082-97156529 Gas Dynamics MESlO -Air Conditioning ME421- Eng. Ahmed El-Sankary I O@TripleA4AU M Heat Transfer ME315 -Thermodynamics 1 & 2 Mob. 98757791  What (HVAC) stands for? Heating, Ventilating, and Air Conditioning. What (ASHRAE) stands for? American Society of Heating, Refrigeration, and Air Conditioning Engineers. ry What is air conditioning? The science of conditioning the air. It may involves heating, cooling, ka humidification, dehumidification, and filtering. an What is the refrigeration? Any method by which one can reduce the temperature of a body or a surface lower than 91 l-S the ambient. What are the applications of refrigeration and air conditioning? 77 A 1. Food processing, preservation and distribution 2. Chemical and process industries 3. Special Applications 75 d 4. Comfort air-conditioning e hm What is thermodynamics? Thermodynamics is the study of energy interactions between systems and the effect of these interactions on the system properties and deals with systems in equilibrium. ob A What are the forms of energy transfer? 98 Energy transfer between systems takes place in the form of heat and/or work. M g. n What is the thermodynamic systems and their types?. E A thermodynamic system is defined as a quantity of matter of fixed mass and identity upon which attention is focused for study. Everything external to the system is the surroundings. The system is separated from the surroundings by the system boundaries. Thermodynamic systems can be further classified into closed systems, open systems and isolated systems. Gas Dynamics ME510 – Air Conditioning ME421 – Heat Transfer ME315 – Fluid Eng. Ahmed El-Sankary Mechanics ME309 – Thermodynamics ME200 – Thermodynamics 2 ME300 Mob. 98757791 What is the difference between heat and work? Heat is energy transferred between a system and its surroundings by virtue of a temperature difference only. The different modes of heat transfer are: conduction, convection and radiation. Any other means for changing the energy of a system is called work. We can have push-pull work (e.g. in a piston-cylinder, lifting a weight), electric and magnetic work (e.g. an electric motor), chemical work, surface tension ry work, elastic work, etc. ka State the conditions for Bernoulli’s equation? Bernoulli’s equation is valid between any two points in the flow field when the flow is an steady, irrotational, inviscid and incompressible. The equation is valid along a streamline for rotational, steady and incompressible flows. 91 l-S 77 A Heating Ventilating and Air Conditioning 75 d e hm Thermal comfort is defined as that condition of mind which expresses satisfaction with the thermal environment. This condition is also sometimes called as “neutral condition”. ob A Thermal comfort is affected by several factors. These are: 1. Physiological factors such as age, activity, sex and health. These factors influence the metabolic rate. 98 2. Insulating factor due to clothing. It affect the rate of heat transfer from the human body. M g. 3. Environmental factors such as the dry bulb temperature, relative humidity, air motion and surrounding surface temperature. n. E Gas Dynamics ME510 – Air Conditioning ME421 – Heat Transfer ME315 – Fluid Eng. Ahmed El-Sankary Mechanics ME309 – Thermodynamics ME200 – Thermodynamics 2 ME300 Mob. 98757791  ASHRAE American Society of Heating Refrigeration and Air 91 ry Conditioning Engineers 77 ka The recommended outdoordesign condition for summer in Kuwait at 2 75 an is DBT 45.7 C and MCWB 20.10C 98 l-S E. ob ASHRAE American Society of Heating Refrigeration and Air ed M Conditioning Engineers hm The recommended outdoordesign condition for summer in Kuwait at 0.4 MCWB A is DBT 47.8 C and 20.6 C. ng E Contact us: 66570082 - 97156529 Gas Dynamics ME510 – Air Conditioning ME421 – Eng. Ahmed El-Sankary @TripleA4AUM Heat Transfer ME315 – Thermodynamics 1 & 2 Mob. 98757791  What does the air conditioning system consist of? An air conditioning system consists of an air conditioning plant and a thermal distribution system. What are the media used in air conditioning system? ry Air, water, or refrigerant used as media for transferring energy from the AC plant to the conditioned space. ka What is the thermal distribution system? A thermal distribution system is required to circulate the media between the conditioned space an and the A/C plant and to introduce the required amount of fresh air into the conditioned space. 91 l-S What are the selection criteria for air conditioning systems? 1. Capacity, performance and spatial requirements 77 A 2. Initial and running costs 3. Required system reliability and flexibility 4. Maintainability 75 d 5. Architectural constraints e What are the classification of air conditioning systems? What are the types of central hm 1. All air systems air conditioning systems? 2. All water systems 3. Air-water systems 1. All air systems ob A 4. Unitary refrigerant based systems 2. All water systems 3. Air-water systems 4. Variable Refrigerant Flow 98 What are the types of unitary refrigerant based systems? (VRF) systems M g. 1. Window air conditioning 2. Split air conditioning n 3. Package air conditioning. E What are the classifications of all air systems? 1. single duct systems can provide either cooling or heating using the same duct, but not both heating and cooling simultaneously. These systems can be further classified into: Constant volume single zone systems, Constant volume multiple zone systems, and Variable volume systems. 2. dual duct systems can provide both cooling and heating simultaneously. These systems can be further classified into: Dual duct constant volume systems, Dual duct variable volume systems. Gas Dynamics ME510 – Air Conditioning ME421 – Heat Transfer ME315 – Fluid Eng. Ahmed El-Sankary Mechanics ME309 – Thermodynamics ME200 – Thermodynamics 2 ME300 Mob. 98757791  What are the advantages and disadvantages of all air systems? Advantages of all air systems: 1. By using high-quality controls it is possible to maintain the temperature and relative humidity of the conditioned space within ± 0.15 C (DBT) and ± 0.5%, respectively. 2. Using dual duct systems, changeover from summer to winter is relatively simple in all air systems. ry 3. It is possible to provide good room air distribution and ventilation under all conditions of load. 4. The complete air conditioning plant can be located away from the conditioned space. Due to this it is possible to use a wide variety of air filters and avoid noise in the conditioned space. ka Disadvantages of all air systems: 1. They occupy more space and thus reduce the available floor space in the buildings. an 2. Balancing of air in large and particularly with variable air volume systems could be difficult. What are the advantages and disadvantages of single duct, constant volume, multiple zone? Advantages: 91 l-S a) Relatively small space requirement b) Excellent temperature and humidity control over a wide range of zone loads 77 A c) Proper ventilation and air quality in each zone is maintained Disadvantages: High energy consumption for cooling, as the air is first cooled to a very low temperature and is then heated in the reheat coils. 75 d e What are the advantages and disadvantages of single duct, VAV systems? hm advantages: a) Lower energy consumption in the cooling system as air is not cooled to very low temperatures and then reheated as in constant volume systems. b) Lower energy consumption also results due to lower fan power input due to lower flow rate, ob A when the load is low. disadvantages: 98 a) There could be problems with ventilation, IAQ and room air distribution when the zone loads M g. are very low. b) It is difficult to control humidity precisely using VAV systems. n c) Balancing of dampers could be difficult if the airflow rate varies widely.. E What are the advantages and disadvantages of dual duct, constant volume systems? Advantages of dual duct systems: 1. Since total airflow rate to each zone is constant, it is possible to maintain proper IAQ 2. Cooling in some zones and heating in other zones can be achieved simultaneously. 3. System is very responsive to variations in the zone load. Disadvantages of dual duct systems: 1. Occupies more space as both cold air and hot air ducts have to be sized. 2. Not very energy efficient due to the need for simultaneous cooling and heating. Gas Dynamics ME510 – Air Conditioning ME421 – Heat Transfer ME315 – Fluid Eng. Ahmed El-Sankary Mechanics ME309 – Thermodynamics ME200 – Thermodynamics 2 ME300 Mob. 98757791  What are the classifications of all water systems? 1. A 2-pipe system consists of two pipes – one for supply of cold/hot water to the conditioned space and the other for the return water. 2. A 4-pipe system consists of two supply pipelines – one for cold water and one for hot water; and two return water pipelines. What are the advantages and disadvantages of all water systems? ry Advantages of all water systems: 1. The thermal distribution system requires very less space compared to all air systems. ka 2. Individual room control is possible. 3. It can be used for new as well as existing buildings (retrofitting). 4. Simultaneous cooling and heating is possible with 4-pipe systems. an Disadvantages of all water systems: 1. Requires higher maintenance compared to all air systems. 2. Draining of condensate water can be messy and may also create health problems if water 91 l-S stagnates in the drain tray. 3. If ventilation is provided by opening windows or wall apertures, then, it is difficult to ensure positive ventilation under all circumstances, as this depends on wind. 77 A What is the fan coil unit and what it consists of? The fan coil unit is used in all water systems in space to transfer heat between the cold/hot water 75 d and the air of conditioned space. It consists of a heating and/or cooling coil, a fan, air filter, drain e tray and controls. hm What is the variable refrigerant flow (VRF) system? Variable refrigerant flow (VRF) systems vary the flow of refrigerant to indoor units based on demand. This makes the VRF technology ideal for applications with varying loads. In a VRF ob A system, multiple indoor fan coil units may be connected to one outdoor unit. The outdoor unit has one or more compressors that are inverter driven, so their speed can be varied by changing the frequency of the power supply to the compressor. As the compressor speed changes, so does the 98 amount of refrigerant delivered by the compressor. Each indoor fan coil unit has its own metering M g. device that is controlled by the indoor unit itself, or by the outdoor unit. As each indoor unit sends a demand to the outdoor unit, the outdoor unit delivers the amount of refrigerant needed to meet n the individual requirements of each indoor unit.. E What are the advantages of VRF systems? 1. Control Means Comfort: providing comfort is to supply heating or cooling when and where it is required without swings in room temperature. 2. Design Flexibility: flexibility provided by the diversity of the product offering. Multiple types and sizes of fan coils are available to fit any application. 3. Cost Effective Installation: it can be a cost effective alternative to traditional systems. 4. Energy Savings: provide energy savings by varying compressor speed and matching the output of the system as closely as possible to the load. Gas Dynamics ME510 – Air Conditioning ME421 – Heat Transfer ME315 – Fluid Eng. Ahmed El-Sankary Mechanics ME309 – Thermodynamics ME200 – Thermodynamics 2 ME300 Mob. 98757791  What are the disadvantages of A VRF System? 1. Initial Cost: more expensive to install than traditional HVAC systems due to their complexity and the need for specialized components. 2. Maintenance: require specialized knowledge and training, which can be an additional cost for building operators. ry 3. Refrigerant Leaks: can pose potential risks if leaks occur. Leaks can result in decreased ka efficiency, higher energy costs, and potential environmental and safety concerns. an What are the advantages and disadvantages of air-water systems? a Advantages of air-water systems: 1. Individual zone control is possible in an economic manner. water. 91 l-S 2. It is possible to provide simultaneous cooling and heating using primary air and secondary 3. Space requirement is reduced. 77 A 4. Positive ventilation can be ensured under all conditions. 5. Since no latent heat transfer is required in the cooling coil, the coil operates dry. Disadvantages of air-water systems: 75 d 1. Operation and control are complicated. e 2. The secondary water coils in the conditioned space can become dirty if the quality of filters used in the room units is not good. hm 3. Shutting down the supply of primary air to unoccupied spaces is not possible. What are the advantages and disadvantages of unitary refrigerant based system? ob A Advantages of unitary refrigerant based systems: 98 1. Individual room control is simple and inexpensive. 2. Each conditioned space has individual air distribution with simple adjustment by the M g. occupants. n 3. Performance of the system is guaranteed by the manufacturer.. 4. System installation is simple and takes very less time. E 5. Operation of the system is simple and there is no need for a trained operator. Disadvantages of unitary refrigerant based systems: 1. As the components are selected and matched by the manufacturer, the system is less flexible in terms of air flow rate, condenser and evaporator sizes. 2. Power consumption per TR could be higher compared to central systems. 3. Close control of space humidity is generally difficult. 4. Noise level in the conditioned space could be higher. 5. Limited ventilation capabilities. Gas Dynamics ME510 – Air Conditioning ME421 – Heat Transfer ME315 – Fluid Eng. Ahmed El-Sankary Mechanics ME309 – Thermodynamics ME200 – Thermodynamics 2 ME300 Mob. 98757791