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Ministry of Agriculture through, through SASSCAL funding, did acquire 3 automatic weather stations in 2018 which where finally installed in 2019 after sites have been determined. These stations from part of the existing SASSCAL weather station network that has been established over the past years. All stations conform to SASSCAL requirements and are inline with WMO standards.

The stations are installed at :

• Dudukabe (Zambezi)
• Okalongo (Ohangwena)
• Omafo (Ohangwena)

Station info can be obtained from www.sasscalweathernet.org

CTS was successful in winning the tender for the refurbishment of the transformer oil storage plant at the van Eck Power station. The project included the following:

1. Cleaning and painting of all oil tanks
2. Automating the entire plant
3. Installation of oil filtration system

Old as well as new transformer oil is stored in different tanks. Color codes on the tank clearly indicate what type of oil is stored in each tank. Old oil – oil removed from transformers during service – is stored until enough has been collected before it is sold.

Clean/new oil is stored in the other thanks that will be used for refilling transformers during routine services. Humidity tends to form inside the oil when it is stored for longer periods. This humidity as well as other dirt particles are removed my means of the Alfa Laval Oil Filtration plant. The process is fully automated and PLC controlled. The operator merely is required to enter the quantity of oil that is to be filtered.

Radar level sensors are installed in each tank to monitor quantity on hand. Maintenance free breathers on each tank prevent access of water moisture into the tank and the buildup of dangerous gases.

A Coriolis custody transfer meter accurately indicates the quantity of old oil the is transferred to third party tankers for selling purposes.

This is a typical photovoltaic (PV) medium scale farm system found on many farms around Namibia. Over the past three years this system grew in PV size from 350Wpeak to ~1200Wpeak.

System specs are:

• PV modules with a total capacity of 1220Wpeak
• 1200VA, 24V Inverter charger
• 40A Solar Charge Regulator
• 360Ah battery bank@24V
• Battery Monitor showing: state of charge (%), charging/discharging current (A), Battery Voltage (V) and time to go (h)
• Switchgear for submersible pump control

The PV modules are mounted on frames facing true north for optimal energy harvesting. During times of limited sunshine, especially the rainy season, battery charging can be increased by starting the generator. Should the AC load increase behind the inverter rating, the generator can support the system to cater for the increased load. No automatic generator start function is included.

Furthermore a second PV system for the Farm workers has been installed to cater for lighting and a TV.

• 2x 90Wpeak PV modules
• 20A Solar Charge Regulator
• 2x 105Ah batteries
• 350VA, 12V inverter

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.

CTS was awarded the tender to install a water heating system for the Hilton Hotel Windhoek.

The system was installed according to the following specifications:

•    2x 250kW gas fired hot water boiler

•    2x 6800 liter hot water storage tank (also known as calorifier)

•    1x Danfoss Aqua drive 11kW for glycol circulation pump control

•    2x Automatic bypass valves to control water temperature inside tank

•    4x Hot water circulation pumps

The boilers as well as glycol circulation pumps and one hot water storage tank were installed in the boiler room located in the upper basement of the hotel. The second hot water storage tank is installed on the 9th floor of the Hilton Hotel. A glycol circulation system connects the two calorifier with the two gas fired hot water boilers. The glycol circulation pumps are controlled from one Danfoss Aqua drive with cascading functionality to control the pumping speed depending on the temperature in the glycol line.

Each hot water boiler is cycled on a 24 hour basis, should the glycol temperature fall below a predetermined threshold for certain period of time the second boiler will start automatically.

Automatic bypass valves guarantee that the water temperature of each calorifier is kept at a constant 60 – 65 degrees Celsius.

Pionieerspark Medical Centre can call themselves a proud owner of a 38kW photovoltaic grid feed system. Considerable savings on the monthly electricity bill are achieved as most of the electricity requirements are produced directly at the customer. Excess energy is fed back into the grid and credited on the monthly electricity bill by City of Windhoek.

The system consists of 144 265W PV modules mounted flat on the roof of the building with 2 Fronius three phase grid feed inverters and remote monitoring via the Fronius App on the cell phone. Remote monitoring allows CTS to advise the client on possible faults and recommended actions to be taken.