Sustainable Designed Air-Conditioned Mosque For Thermal Comfort

Transcription

1 Sustainable Designed Air-Conditioned Mosque For Thermal Comfort Presented by Prof. Dr. Essam E. Khalil, Fellow ASHRAE, Fellow ASME, Fellow AIAA Professor of Mechanical Power Engineering Prepared by Redhwan N. AL-Gabri and Essam E.Khalil Faculty of Engineering, Cairo University, Cairo-Egypt 47. Međunarodni kongres i izložba o KGH, Beograd, th International HVAC&R Congress and Exhibition, 1

2 Outline 1) Objective 2) Introduction 3) Literature Review 4) Thermal Comfort 5) Mathematical Modeling 6) Results 7) Conclusions and Suggested Future Work 47. Međunarodni kongres i izložba o KGH, Beograd, th International HVAC&R Congress and Exhibition, 2

3 (1) Objectives: This Paper devoted to study the air flow distribution and its properties in an air-conditioned mosque. Study the effects of changing worshipers' number in prayer Five times on the airflow properties inside the mosque. The study of the distribution of temperature and relative humidity and air velocity distribution in the times of the five daily prayers in the mosque. Relationships between Thermal Comfort and air flow conditions 3

4 (2) Introduction The present thesis focuses on temperature, relative humidity, and thermal behaviors in mosque where satisfying the human thermal comfort conditions in Five daily prayers. Thermal comfort is a condition of mind which expresses satisfaction with the surrounding environment, most important factors influencing thermal comfort are:- Environmental factors: Air temperature Air velocity Humidity Personal factors: Metabolic rate Clothing Insulation 4

5 (3) Literature Review Enad [23] used four turbulence models for four case are:case 1: Use Standard k ε model, Case 2: Use Renormalization-group (RNG) k ε model, Case 3: Use Large eddy simulation (LES) model and Case 4: Use Realizable k ε model with the continuity, energy, momentum, and species transport equations.using computational fluid dynamics (CFD) simulation a commercial CFD code, namely FLUENT version 14 to achieve the ASHRAE comfort conditions within the occupied zones in the SaydaZeinab s Mosque for the average air velocity, average temperature and average relative humidity. The mesh sizes' number in their work exceeded 2,100,000 approximately. The thermal comfort prediction through their work was based on the PMV and the PPD model. Results showed that the Renormalization-group (RNG) k ε model was best. This study was conducted on a mosque an archaeological Mosque of moderate capacity (900 prayers) Located in SaydaZeinab downtown Cairo. AL-Gabri[30] studied the numerical investigation of the influence of location and number of persons on airflow properties in Mosque and focuses on airflow patterns, thermal behavior and carbon dioxide dispersion in mosque where large number of prayers standing. The study is carried out using computational fluid dynamics (CFD) simulation techniques as embedded in the commercially available CFD code (FLUENT 15). The CFD modelling techniques solved the continuity, momentum and energy conservation equations in addition to comfort parameters PMV and PPD based on Fanger s model and RNG k ε model equations for turbulence closure. The results showed that increasing of prayers numbers are a significant negative effect on the thermal comfort, thus leads to increase required convection for thermal. 5

6 Literature Review Why Mosques must be studied? The Mosque is a place of worship, reciting Quran and prayer. The Mosque is a place for celebrations The Mosque is a place for consultation and exchanging views. The Mosque is as University for Learning and Teaching. The Mosque is a home for the needy and an eating-place for the poor, needy and place where people ask for help. 6

7 (4) Prediction of Thermal comfort Fanger s Contributions in Thermal Comfort: Predicted Mean Vote (PMV) Predicted Percentage Dissatisfied (PPD %) PMV Thermal Sensation Hot Warm Slightly Warm PPD(%) Neutral 5-1 Slightly Cool 25-2 Cool 75-3 Cold 100 7

8 (5) Governing Equations The governing equations in this model are: Continuity equation which governs the mass flow rates in the computational volumes. Momentum equations that govern the flow velocities in and out of each control volume. Energy equation. Species transport equation. Turbulence models equations. 8

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10 Energy Equation Species Equation where Y i R i S i J i t ρy i +. ρvy i =. J i + R i + S i Local mass fraction of each species in each control volume The net rate of production of species i by chemical reaction The rate of creation by addition from the dispersed phase The diffusion flux of species i 10

11 PPD = exp[ ( PMV PMV 2 ) ] 11

12 Mosque Configurations The mosque named Nabiha Yaken is located in Cairo, with area of 820m^2 and a height of 6 m, with maximum capacity (around 900 worshipers), with a private space for books, Imam room, spaces for air conditioners, shoes and...etc. Figure shows horizontal plan view of Nabiha Yaken mosque. 12

13 Photos for the Interior of Nabiha Yaken mosque 13

14 Photos of the Exterior of Nabiha Yaken mosque 14

15 Mosque space Modeling The Mosque geometry modelled by using FLUENT 15

16 A/C Units Modeling The Mosque is Air-Conditioned with commercial floor (free) mounted units, each of cooling capacity BTU/Hr. The units are modelled with typical dimensions of 2 [m] height x 0.6 [m] length x 0.4 [m] width, Such that supply air outlet (blue collared) is of typical dimensions 0.3 [m] height x 0.6 [m] length, while return air inlet (red collared) is of typical dimensions 0.9 [m] height x 0.6 [m] length, the mosque is air conditioned with (9) commercial floor mounted units. The units are also of same cooling capacity are distributed in such a balanced configuration all over the mosque area. The purpose of this distributed is to achieved better indoor environment accepted by occupants as simulation is shown in this figure. 16

17 Worshiper Modeling Worshiper body in a standing posture is modeled as a vertical rectangular box enveloping the body with dimensions 1.7 [m] height x 0.25 [m] width x 0.5 [m] length. 17

18 Praye r Table : Shows the studied different cases NO. NO. Mesh NO. Units A/C Boundary Condition for Roof and Walls Notes Case Constant temperature Lights turn on FAJR Case Constant Heat Flux Lights turn on Case Radiation-Solar Energy Lights turn on Case Constant temperature Lights turn off DHUHUR Case 5 Case Constant Heat Flux Radiation-Solar Energy Lights turn off Lights turn off Lights turn off Radiation-Solar 18

19 Table : Shows the studied different cases Prayer ASER MAGHREB ESHAA NO. Case 8 NO. Mesh NO. Units A/C Boundary Condition for Roof and Walls Constant temperature Notes Lights turn off Case Constant Heat Flux Lights turn off Case 10 Case11 Case12 Case13 Case14 Case15 Case Radiation-Solar Energy Constant temperature Radiation-Solar Energy Constant temperature Constant temperature Radiation-Solar Energy Radiation-Solar Energy Lights turn off Lights turn on Lights turn on Lights turn on Lights turn on Lights turn on Lights turn on 19

20 Table : Shows the rows and prayers number. prayer number of worshipers with Imam number of worshipers without Imam number of rows number of worshipers in each row FAJR (R1,R2,R3,R4)= (46,49,49,42) DHUHUR (R1,R2,R3,R4,R5)= (46,49,49,42,39) ASER (R1,R2,R3,R4,R5,R6)= (46,49,49,42,39,32) MAGHREB (R1,R2,R3,R4,R5,R6,R7)= (46,49,49,42,39,32,31) ESHAA (R1,R2,R3,R4,R5,R6,R7,R8)= (46,49,49,42,39,32,31,39) 20

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22 Boundary Conditions Occupant (Worshiper) Boundary Details Occupant Data Gender Activity type Metabolic rate Skin temperature breathing rate Species mass fraction from mouth CO2 concentration (volume or mole fraction) in the human respiration value Male Standing, relaxed 1.2 [met]. 307 [K] 8 L/min kg w / kg d.a L co2 /L a 22

23 Indoor Space Environment Boundaries 23

24 Planes that show results A vertical plane (XZ) at Y= 9.5m from Qebla. A vertical (YZ) Plane at X= 12.5m from LIFT SIDE A horizontal (XY) Plane at 1.6m above floor level 24

25 Case 3 25

26 Case 3 26

27 Temperature Contours _ Case 15 27

28 Case 7 28

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30 Case 15 Case 16 30

31 Case 15 Case 16 31

32 Case 1 Temperature contours (K). PMV contours Velocity contours,(m/s). RH contours (%). PPD contours 32

33 Temperature contours (K). RH contours (%). Case 6 Case 7 33

34 Velocity contours (m/s). Case 6 Case 7 34

35 Temperature contours (K) ASER Case 8 T=Constant Case 9 Heat Flux=Constant Case 10 Solar Energy and Radiation 35

36 RH contours (%) ASER Case 8 Case 9 Case 10 36

37 Velocity contours (m/s) ASER Case 8 Case 9 Case 10 37

38 PMV ASER Case 8 Case 9 Case 10 38

39 PPD ASER Case 8 Case 9 Case 10 39

40 Case10 ASER Case12 MAGHREB Temperature contours (K) RH contours (%) 40

41 PMV contours PPD contours ASER Case 10 MAGHREB Case 12 41

42 Temperature contours (K) ESHAA Constant Wall Temperature Velocity contours (m/s) PMV Case 13 Case 14 42

43 ESHAA Solar Energy and Radiation Temperature contours (K) Velocity contours (m/s) PMV Case 15 Case 16 43

44 Temperature contours (K) ESHAA Velocity contours (m/s) PMV Case 13 =Constant Case 15 Solar Energy and Radiation 44

45 (7) Conclusions 1- The increasing in worshiper number from prayer to prayer showed a significant negative effect on the thermal comfort, thus number of worshipers increasing in the Mosque leads to increase convection required for thermal comfort. 2- Was concluded that the case of radiation, solar energy is the case, more accurate and realistic and most of the cases of constant temperature and evidence of heat flux 3- Increasing number of air conditioner to 14 A/C on case 7 will lead to more homogeneous temperature distribution and minimize the temperature of air in Mosque to worshiper comfort. 4- It can be dispensed with for the operation of Four air conditioners in the mosque and that in times of FAJR, MAGHREB and ESHAA, as is evident in the case16 due to the fact that the air temperature is good compared with the times of prayer DHUHUR and ASER. Saving energy in this case = 44% 45

46 Recommendations for Future Work 1. Experimental work should be implemented for the validation with these numerical results. 2. Mosque users are normally fairly well dressed during both summer and winter seasons. Therefore, middle range of the design temperature is favorable with little summer/winter variations. 3. Study the effect of using ceiling fans in the air distribution on the worshipers with the units of cooling. 46

47 Thank you for your kind attention Any questions? 47