ENERGY EFFICIENCY TECHNOLOGIES AND ENERGY SAVINGS POTENTIALS FOR COLD ROOMS

1. ENERGY EFFICIENCY TECHNOLOGIES AND ENERGY SAVINGS POTENTIALS FOR COLD ROOMS

2. Tshwane University of Technology • Faculty of Engineering and the Built Environment • Department of Mechanical Engineering • Master Student: Mr. Jean-Claude MULOBE (Presenter) • Supervisor: Prof. Zhongjie Huan • INDUSTRIAL AND COMMERCIAL • USE OF ENERGY • Cape Town, 14-16 August 2012 • SOUTH AFRICA

3. I. INTRODUCTION • In foods manufacturing the energy is used through: • Refrigeration system; Cooling facilities (cold rooms); Air-conditioning system; Cooling tower ; and Lighting system, ect. • More than 50% of energy demand is from refrigeration and cooling facilities. • Since energy prices risen dramatically the attention of foods industries is focusing on the development of the most efficient technologies • Energy efficiency is an effort reduces higher energy demand to provide production and services • In South Africa foods industries, approximately 99% of energy usage is electrical • Energy efficiency technologies and energy saving potentials for cold rooms

4. II. OBJECTIVE AND MOTIVATION • The objective of this study is to develop the efficient technologies, thereby reduce as much as possible higher energy demand in cooling process for cold rooms • Then contribute to the success of the energy performance program • The food industry is among of the large users of energy and therefore it has a major role to play in reducing greenhouse emissions HE-Coils Bulk Energy efficiency technologies and energy saving potentials for cold rooms

5. III. REFRIGERATION SYSTEM (CHILLING SYSTEM) SCHEMATIC Fig 1 Energy efficiency technologies and energy saving potentials for cold rooms Click to add caption [10.5, italic] : Chilled Water : Condenser Water

6. Fig 2 Energy efficiency technologies and energy saving potentials for cold rooms

7. Cooling facilities (cold rooms) Energy efficiency technologies and energy saving potentials for cold rooms

8. III.1 COLD ROOM A cold room is the specific place which is maintained at low temperature environment to provide safety, minimise deterioration, and pollution of products after harvest into the cold chain. Fig 3 Energy efficiency technologies and energy saving potentials for cold rooms

9. III. 2 COLD ROOM ENERGY CONSUMPTION Table1 Figure 3 internal cold room Click to add caption [10.5, italic] Fig 4 Energy efficiency technologies and energy saving potentials for cold rooms

10. IV. CASE STUDY Tshwane Market ripening banana section: 66% of energy usage in this area is from refrigeration system + cooling facilities (Cold Rooms), and the average Energy consumption is in the range of 5 to 10.5 kWh/ Ton-Day during cooling process. Fig 6 Fig 5 Energy efficiency technologies and energy saving potentials for cold rooms

11. V. SAVINGS TECHONOLOGIES FOR COLD ROOMS • 1.COULORING AND SHADING TECHNOLOGY ON THE EXTERNAL WALLS AND ROOF • The use of extracting fan can be reduce: • (1) Shading by Convection + Conduction : Energy efficiency technologies and energy saving potentials for cold rooms

12. (2): Colour; white colour on roof and Wall in place of dark one will be of great benefit in hot and sunny climates Energy efficiency technologies and energy saving potentials for cold rooms

13. 2. AIRFLOW OPTIMISATION AND STACKING METHOD: • From many investigations in the literature, the flow resistance induced by: • Container (Box) • Product properties • Bulk confinement ratio • Affecting the cooling efficiency and effective box venting could enhance • the cooling efficiency • Stacking arrangement with a low porosity will produce a higher pressure drop than a stacking arrangement with a high porosity Energy efficiency technologies and energy saving potentials for cold rooms

14. The airflow resistance was mainly expressed by either Ramsin or Darcy-Forchheimer equation, used to estimate airflow resistance trough bulk fruit, vegetables and vented packages. Fig 7 Energy efficiency technologies and energy saving potentials for cold rooms

15. Four different random stacking in Euro Pool System (EPS) were analyzed and the result gave different velocity according to the their stacking method. • Fig 8 • Fig 9 Figure 8 Energy efficiency technologies and energy saving potentials for cold rooms

16. The figure shows the pressure drop over the individual components of the boxes, the sum of those and pressure drop over the system as a whole, which can be simulated to the bulk case. • The result have shown that the total pressure drop was also expressed in the form of Darcy-Forchheimerand Ramsin power-law equations . Fig 10 Pressure drop through vented EPS boxes loaded with 32 spheres of 75 mm diameter per box: C1 bulk without box; C2 box without bulk; C3 loaded box from sum of pressure drops; C4 loaded box from CFD simulation; C5.2 loaded boxes from sum of pressure drops; C6. 2 loaded box from CFD simulation. Energy efficiency technologies and energy saving potentials for cold rooms

17. 3. The variable speed drives technology (VSD) on evaporator fans motor (EFMs). • From the ideal fan is law: Evaporator Fan Motors Energy efficiency technologies and energy saving potentials for cold rooms

18. 3. The variable speed drives technology (VSD) on evaporator fans motor (EFMs). • The cooling load • Varies during the cooling period with the maximum heat load at the beginning of the process. • Once the food surface temperature reaches a temperature close to the air temperature it is possible to reduce the fan power and reduce energy to the fans without compromising the cooling times by the VSD. Energy efficiency technologies and energy saving potentials for cold rooms

19. The VSD technology provide the opportunity to save 15-40% of the energy demand by electrical motors. • Extend equipment lifetime by allowing gentle start-up and shutdown. Energy efficiency technologies and energy saving potentials for cold rooms

20. VI. CONCLUSION The improvement in energy efficiency are most often achieved by adopting a more efficient technology or production process. The efficient technologies studying will lead to save enough of the energy usage in foods manufacturing, thereby increase the benefits and reduces higher energy demand. This study is also a contribution to the alleviation of South Africa is energy problems. Energy efficiency technologies and energy saving potentials for cold rooms