Numerical Determination of Comfort Level (PMV/PPD) in an Office Model with Jet Nozzle

Öz

In this study, the air is blown to an office room which has dimensions   3x4x3,5 m by a jet nozzle. Office room includes a human, a refrigerator, a light and a computer, The office conditions were assumed to be in summer in Osmaniye province and the heat loss gain was calculated by considering 100% fresh air flow rate and blowing temperature were found according to this evaluation,. Heat flux is given to the all office walls with heat loss and gain calculation. The velocity and temperature distribution of the jet nozzle are simulated with the ANSYS-FLUENT program. The conservation of mass, the conservation of turbulent momentum, the kinetic energy of the turbulence (k), and the velocity of propagation (ɛ) of the kinetic energy of the turbulence equations are used. The Predicted Mean Vote (PMV) and Predicted Percentage Dissatisfied (PPD) values at 0.1, 0.6, and 1.1 meters above the ground level of office were calculated from these values. The areas of thermal satisfaction and dissatisfaction in the room were determined with PMV PPD contours. 

Anahtar Kelimeler

• HVAC,Jet nozzle,PMV,PPD

Jet Lüle ile İklimlendirmesi Yapılan Bir Ofis Modelinde Konfor Seviyesinin (PMV/PPD) Sayısal Olarak Belirlenmesi

Öz

Bu çalışmada, içerisinde insan, buzdolabı, lamba ve bilgisayar bulunan ve boyutları 3x4x3,5 m olan bir ofise jet lüle ile üfleme yapılmıştır. Ofisin Osmaniye ilinde yaz şartlarında olduğu varsayılmış ve içerisine %100 taze hava verildiği düşünülerek ısı kaybı kazancı hesabı yapılmıştır.  Bu hesaba göre debi ve üfleme sıcaklığı bulunmuştur. Duvarlara, tabana, tavana ısı kaybı ve kazancı hesabına göre ısı akısı verilmiştir. Ayrıca; insan, dolap, lamba ve bilgisayara ısı akısı verilmiştir. Ofise yerleştirilen jet lülenin hız ve sıcaklık dağılımı ANSYS-FLUENT programı ile sayısal olarak elde edilmiştir. Sayısal hesaplamada sürekli koşullarda; kütlenin korunumu, türbülanslı momentumun korunumu, türbülans kinetik enerjisi (k) ve türbülans kinetik enerjisinin yayınım hızı (ɛ) denklemleri kullanılmıştır. Buradan elde edilen değerler ile zeminden 0,1, 0,6, 1,1 metre yüksekliğinde Isıl çevreden memnuniyet (Predicted Mean Vote-PMV) ve Isıl Çevreden Memnuniyetsizlik (Predicted Percentage Dissatisfied-PPD) değerleri hesaplanmıştır. Oluşturulan PMV ve PPD konturlarında jet lüle ile üfleme yapılan oda içerisindeki termal memnuniyet ve memnuniyetsizlik alanları tespit edilmiştir. 

Anahtar Kelimeler

• HVAC,Jet lüle,PMV,PPD

Kaynakça

1. 1. https://www.designingbuildings.co.uk/wiki/Th ermal_comfort_in_buildings.
2. 2. Mihliyanlar, H., Kartal, S., Erten, Ş.Y., 2017. Yükseköğretim Yapılarında Isıl Konfor Şartlarının Araştırılması;Süleyman Demirel Üniversitesi Fen Bilimleri Enstitüsü Dergisi, 21(3), 917-927.
3. 3. ASHRAE, ANSI/ASHRAE Standard 55, 2013. Thermal Environmental Conditions for Human Occupancy, American Society of Heating, Ventilating and Air-conditioning Engineers, Atlanta.
4. 4. ISO Standard 7730, 2005. Ergonomics of the Thermal Environment-analytical Determination and Interpretation of Thermal Comfort Using Calculation of the PMV and PPD Indicesand Local Thermal Comfort Criteria, International Organisation for Standardisation, Genova.
5. 5. Parsons, K., Human, 2002. Thermal Environments, the Effects of Hot Moderate and Cold Environments on Human Health, Comfort, and Performance, Third Edition, CRC Press, Taylor&Francis Group. 257-268.
6. 6. He, G., Yang, X., Srebric, J., 2005. Removal of Contaminants Released from Room Surfaces by Displacement and Mixing Ventilation: Modeling and Validation. Indoor Air. 15, 367-380.
7. 7. Budaiwi, I., Abdou, A., 2013. HVAC System Operational Strategies for Reduced Energy Consumption in Buildings within Termitten Occupancy: the Case of Mosques. Energy Conversion and Management. 73, 37-50.
8. 8. Schiavon, S., Melikov, A.K., Sekhar, C., 2010. Energy Analysis of the Personalized Ventilation System in Hot and Humid Climates. Energy and Buildings, 42, 699-707.

9. 9. Fong, M., Hanby, V., Greenough, R., Lin, Z., Cheng, Y., 2015. Acceptance of Thermal Conditions and Energy Use of Three Ventilation Strategies with Six Exhaust Configurations for the Classroom. Building and Environment, 94, 606-619.
10. 10. Salvalai, G., Pfafferott, J., Sesana, M.M., 2013. Assessing Energy and Thermal Comfort of Different Low-energy Cooling Concepts for Non-residential Buildings, Energy Conversion and Management, 76, 332-341.
11. 11. Wong, L., Mui, K., 2009. An Energy Performance Assessment for Indoor Environmental Quality (IEQ) Acceptance in Air-conditioned Offices. Energy Conversion and Management, 50, 1362-1367.
12. 12. Kharseh, M., Altorkmany, L., Al-Khawaj, M., Hassani, F., 2014. Warming Impact on Energy Use of HVAC System in Buildings of Different Thermal Qualities and in Different Climates. Energy Conversion and Management, 81, 106-111.
13. 13. Ahmed, A.Q., Gao, S., 2015. Thermal Comfortand Energy Saving Evaluation of a Combined System in an Office Room Using Displacement Ventilation, World Academy of Science, Engineering and Technology International Journal of Mechanical and Mechatronics Engineering, 9(6).
14. 14. Kuo, J.Y., Chung, K.C., 1999. The Effect of Diffuser’s Location on Thermal Comfort Analysis with Different Air Distribution Strategies. Journal of Building Physics. 22, 208-29.
15. 15. Liu, S., Novoselac, A., 2015. Air Diffusion Performance Index (ADPI) of Diffusers for Heating Mode Building and Environment, 87, 215-223.
16. 16. Ahmad, S.T., Mahdi, A.A., Husein, H.M.A., 2013. A Theoretical Study for Cold Air Distribution to Different Supply Patterns, International Journal of Engineering Technology IJET-IJENS 13, 04.
17. 17. Park, H., 2005. CFD Analysis Assists in Optimization of Thermal Displacement Ventilation for an Elementary School Auditorium, Design Solution Section, HPAC Engineering.
18. 18. Memon, R., Chirarattananon, S., Vangtook, P., 2008. Thermal Comfort Assessment and Application of Radiant Cooling: A Case Study. Building and Environment, 43(7), 1185-1196.
19. 19. Stamou, A.I., Katsiris, I., Schaelin, A., 2008. Evaluation of Thermal Comfort in Galatsi Arena of the Olympics “Athens 2004” Using a CFD Model. Applied Thermal Engineering 28(10), 1206-1215.
20. 20. Song, G.S., Lim, J.H., Ahn, T.K., 2012. Air Conditioner Operation Behaviour Based on Students’ Skin Temperature in a Classroom. Applied Ergonomics 43(1), 211-216.
21. 21. Muhio, S., Butala, V., 2004. The Influence of Indoor Environment in Office Buildings on Their Occupants: Expected–unexpected. Building and Environment, 39(3), 289-296.
22. 22. ASHRAE Handbook 1997. Fundamentals, Nonresidential Cooling and Heating Load Calculations, Atlanta, USA.
23. 23. Foda, E., Sirén, K., 2014. Evaluating the Thermal Comfort Performance of Heating Systems Using a Thermal Manikin with Human Thermo Regulatory Control, 25(1), 191-202.