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A new 7,1kWp Solar Home System for Net Metering was installed at a private residence in Windhoek.

System Specifications are:

• Grid connected with Net Metering
• 24 x 295W Canadian Solar PV modules. Total 7,1kWp.
• 1 x Fronius Primo 8,2-1
• Roof mounted with IBR sheeting
• Remote Monitoring and Energy Meter.

An off gird PV system with generator back up was installed at the Gcwatjinga clinic south east of Rundu. The system comprises of the following components:

• 6.24 kW PV array
• 2x Victron BueSolar 150V/70A MPPT regulator
• 600Ah Battery capacity
• Inverter/Charger, Victron Multi, 48V/8000VA
• System Monitoring (BMV700, Color Control GX)

The clinic was connected to the grid, which at time of system design and installation the grid connection plans were unknown to the engineer. As the clinic has PV installed, the existing system has been configured such as to allow for grid connection once the batteries reach a predefined SOC. This guarantees a continuous supply of power to the clinic and nurse houses.

In addition to the grid, a backup generator is incorporated in case PV as well as grid failure occur.

Central Technical Supplies was approached by the University of Stellenbosch to take part in a tender to supply a solar resource measurement station to the Namibia University of Science and Technology in Windhoek.

We were successful in winning the tender. The station is based on the Kipp and Zonen Solys 2 sun tracker with CMP 10 Pyranometer and CHP1 Pyrheliometer.

The station is based on the CR1000 logger from Campbell Scientific and measures wind speed and direction as well as ambient temperature, humidity and rain in addition to the solar resource data.

Central Technical Supplies (Pty) Ltd. – Geiger Engineering (CTS) was approached by Farmers Meat Market Mariental to design, supply and install a solar water heating system with the aim to reduce the monthly diesel consumption as two diesel boilers are operated to heat water up to 82 deg. C for production purposes.

The water requirements of the abattoir are as follows:

1. 2,000 liter/hour @ 45 C°
2. 3,000 liter/hour @ 60 C°
3. 500 liter/hour @ 82 C°

This adds up to a total daily water requirement at 60 deg. C of roughly 25,000 liter.

The system is design such as to preheat water from 18 deg. C to between 50 deg. C and 60 deg. C before supplying the diesel boiler system, thus reducing runtime and diesel consumption of the diesel boilers. A 20,000L stainless steel tank (non pressure tank) manufactured locally according to CTS design, acts as the buffer tank for the daily water requirement. A total of 120 flat plate collectors supplied by Solsquare Namibia with a total surface area of 300 m2 are connected by means of a 450kW Alfa Laval flat plate heat exchanger to the water tank.

A set of two Calpeda circulation pumps connected to Danfoss variable speed drives and a timer circuit guarantees at all times that the heat from the collectors is effectively transported to the water tank. Flow as well as temperature monitoring on all four ports of the heat exchanger make it possible to determine the instantaneous as well as accumulated kWh produced from the collector field.

Furthermore additional heating energy is obtained from the ammonia refrigeration plant. A heat exchanger is installed on the ammonia discharge side before the existing cooling towers to be able to heat the water during night time as well, as this is the time when the refrigeration plant runs at full capacity to cool down the newly slaughtered meat in the cold rooms. Again flow control and temperature monitoring on the hot water side of the heat exchanger accurately indicate heating energy obtained from the refrigeration plant.
A total of four pump sets have been installed and pumps are cycled on a 24 hour basis in automatic mode. Should at any given time a pump fail, the system can be switched to manual mode to be able to repair the pump without system down time and a resulting increase in diesel consumption.

All systems components are sized such as to allow for future heating capacity upgrades should it be required.

After a year of operation, the plant is performing better than expected and the client is able to safe nearly N$ 60,000 per month on diesel costs, bringing the payback period of the entire system down to below two years. This clearly shows that solar energy, be it for heating or for electricity production, surely is the way forward for a cleaner and greener future for generations to come. CTS is proud to be part of making Namibia and the world a better place for our grandchildren to live in.

After successful completion of the Omusati off grid electrification project, CTS was successful in winning the bid for the second phase of containerized PV solutions for the Kunene region. With the experience gained from phase 1, the containers were optimized in many ways. The final design consisted custom build 20ft container by Namspace in Swakopmund.

Sites that were electrified in the Kunene region are:

• Otjitjekua School
• Otjiu School
• Otjiu Hostel
• Epupa School

The project included the following:

• Upgrading of all government building wiring as per national standard for 4 sites in the Kunene region:
• Manufacture, supply and install container power units for these sites.

The power containers consisted of ca 2.8kW of PV modules installed on the roof as well as 4,500 Ah of battery capacity. Five kVA inverter charger and two 70A BlueSolar Charge regulator all from Victron Energy complete the system. Remote monitoring of all sites is achieved by using the Victron Color Control GX unit.

A 71kW grid tied (Nampower ) PV system was installed at the Klein-Aus Vista Lodge just outside Aus. Remote Monitoring and Energy meter is included to obtain precise information about own consumption as well as exported power. This aids in future electrical reticulation upgrades and designs.

System Specifications are:

• 240 x 295W Canadian Solar PV modules
•  3 x Fronius Symo 20.0 – 3 Grid Inverter
• Shed roof mounting with structure for IBR roof sheeting
• AC & DC surge and Lightning protection
• Configured for remote monitoring