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Central Technical Supplies was once again awarded the tender to electrify 4 remote localities in the Otjozondjupa Region of Namibia. Custom build containers where installed on site with SMA Sunny Island 8.0 inverter installed. In addition the offered lead acid battery technology has been replaced by state of the art lithium batteries reducing system maintenance. The use of AC coupled technology did allow for the SunnyBoy solar inverter to be in installed inside relevant buildings on which PV modules are mounted. All components are interlinked by means of wireless technology to allow for remote monitoring where GSM signal is of sufficient strength. System sizes vary form 3kW, 12kW, 15kW to 20kW of PV power while inverters are as much as 3 in a single phase cluster.

Sites that were electrified are:

• Nhoma
• Aasvoel Nes
• Kanovlei
• Grashoek

DeBeers Namibia published a tender for the supply and installation of a weather monitoring system at the Oranjemund Airport. CTS was awarded the tender based on price, knowledge of the meteorological measuring equipment as well as quality of products. At time of installation the station was the most advanced aviation weather station in Namibia.

Technical Details of the system installed:

• Ceilometer at end of runway 20 to measure cloud height at three levels up to 7,500m
• Runway Visibility and Present Weather sensor at stop end of runway 20.
• Present weather sensor monitors 7 different types of precipitation
• visibility sensor takes background luminescence into account
• Wind speed and direction a touchdown runway 20.
• Wind speed and direction, rain as well as barometric pressure at stop end runway 20
• AviMet server for processing of all data
• 3 workstations spread along the buildings for weather monitoring and supervision purposes
• ATIS voice system transmitting on aviation frequency as well as telephone dial in the current weather conditions

All communication between the equipment and the AviMet server is based on wireless transmission to reduce cabling costs.

The weather information can be picked up rough 100 NM away from the airport by all approaching aircraft.

The installed photovoltaic system at Elavi Clinic caters for the power supply to the clinic as well as the nurse houses. A 6.2kW PV module array generates enough power for the energy requirements. Should this not be sufficient the batteries can be charged by a backup generator.

The system consists of the following:

• 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)

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.

In early 2017 Stier Vente Chartered Accountant did take the decision to move to renewable energy. A 17kW grid feed system was installed on the roof of the office building to reduce the monthly electricity bill.

A total of 67 260W PV modules and a SMA SunnyTripower 17kW inverter was installed. Remote monitoring allows CTS to advise the client on possible faults and recommended actions to be taken.

A 200kW PV peak grid tied PV system was installed at Quality Tyres Lafrenz Industrial Area. Remote monitoring of all 10 inverter allows for early fault detection and system degradation as well as maintenance planing.

System Specifications are:

• 680x 295W Canadian Solar modules
• 10x Fronius Symo 20.0-3 Grid Inverter
• Roof mounting structure for IBR roof sheeting
• AC surge protection
• configured for remote monitoring