PAKISTAN, BEING dependent mainly on agriculture and livestock, is the sixth major milk producing country of the world. Local consumption of milk is still high but the consumers especially in urban areas are gradually shifting to packed milk. What factors could be mentioned behind this major shift, but it is fact that the rising demand processed milk has give encouraged the packed milk sector and related economic activities in the country. Major activity of this whole process – from local buffalo shed to the release of processed milk from the milk plant – is the transportation of milk by maintenance its quality, healthy as well as freshness. Milk chiller has got a pivotal role in this whole process. But now keeping milk healthy and qualitative has got a phenomenal importance especially when majority of the rural areas of Pakistan are experiencing 8-16 hour power loadshedding. An extensive research was also done to cope with the long-hour power outages but uptil the last year was no tangible progress in this regard.
Presently, power supply from grid station or generator (alternative arrangement) is commonly in use in Pakistan to keep milk chillers functional, however, the regular increase in oil prices has made the generator option very expensive – virtually unaffordable. A complete milk chiller (having capacity of 500 liters) has all equipments especially compressor, mixer and condenser that needs uninterrupted power supply to keep the chiller working. For the start-up it needs at least 10,000 watts, over 50 amperes having 220 volts while its smooth power supply is 33,000 watts, 15 amperes with 220 volts. The major problem with the conventional power supply options – generator or solar – that, through experience, have proved a flop: In case of opting for generator you need a heavy capacity generator to meet the start-up power supply requirement which is 10,000 watts. Regular work of such heavy generator costs heavily while on the other hand if you continue availing on and off option, the lifeline of the installed generator reduces and would need a major overhaul about after five years. Similarly, solar plant having 10,000 watts capacity is too expensive and needs a wide area for installation, and of course small solar plant is unable to meet the requirement.
Sira, a power solution provider company from Italy, however, emerged successful with a hybrid power management solutions especially for milk chillers that can now effectively capable not only to meet the power requirement but also are cost effective as well as energy savor.
The Sira Power Management Solution (EMS): With EMS can be used a standby generator and no more a prime one that saves capital expense. Use of a smaller diesel generator reduces only a little bit the fuel consumption (0.3/0.4 liter x kwhr) but slashes the capital expense, space need and mantainance cost. This EMS system has three different operating modes that are hybrid mode, standalone and automatic mode.
Standalone: This system run as a standalone photovoltaic system
Automatic: In day time it works in standalone mode and in night time in hybrid mode
Hybrid: Full solar
The Power Management Solution has gained the central position in the Sira power solutions – EMS. It manages different sources of electricity – grid, solar photovoltaic, wind turbine, batteries and diesel generator. It has the to ability to manage three different loads with different priorities – grid, solar & wind and battery & generator.
The advanced features in the EMS offer that the EMS can run remotely with / without full telemetry system with the capability to auto turn-on and off the Genset when needed by the system including sensing of the voltage and frequency.
EMS sends remainder for first level of maintenance and yearly scheduled maintenance of genset through SMS.
Sira installed its first EMS solution for milk chillers at Nestle Milk Collection Center at Kot Momin (Pakistan) 6 months ago and it is running as per the design specifications.
The power system configuration at the centre prior to solar power was the grid and generator. The power fluctuation for the centre was a critical issue that needed to be redressed effectively in order to keep the chiller and other equipments working uninterruptedly.
At the centre, the load is made of compressor/condenser of the milk chiller and mixer, water pump for washing the milk chiller, milk transfer pump (located onboard the truck), and Gerber machine for milk analysis.
• From the refrigerator (chiller) the milk is transferred to the truck.
• The milk chiller is washed, pump rating @ 750 watts, for half an hour.
• Milking are 2 per day
During the startup of the chiller the power demand can be as high as 10kw which is approximately 3 to 4 times more than the average load which is 3,300 Watts. The system must be capable to maintain this peak load. This extra load is replenished with the heavy batteries that remained charged with solar energy during day hours. In the past, there was no formula to relay both Direct Current and Alternative Current from the same path. However, the Sira Energy Manager has the multiple abilities to provide uninterrupted power supply to the chiller. In case of loadshedding from the grid during day hours, the Energy Manager gets power from the solar panels, while during the night hours it gets power from batteries that are recharged from the solar power during the day hours.
One of the system’s design parameters was to utilize only the space available within and top of the room where the chiller is installed (8×10 ft). The system to be designed for harsh loadshedding conditions, from 8 to 16 hours per day, and without the use of the diesel generator.
On a typical load of 3.3KW milk chiller the EMS solution can save 90% of operational expenses as compared to a traditional power set up of Grid and Genset. Thus the ROI or payback is less than 3 years. EMS system also helps reduce the peak demand load on the Grid which helps the DISCOs with immediate results.
Pakistan is being plunged into the severe energy crisis with every day passing and the government of Pakistan is hectically involved in exploring the alternative energy sources or ensuring proper load management so that the pace of national economic activities is maintained. To achieve the goals of economic progress, it needs to opt for power management solutions and Sira, through its successful performance, has qualified to be the top runner in providing the best solution to the electricity problems of Pakistan.