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After close to 20 years of operation, the existing electrically heated hot water boilers were replaced. A modern, energy efficient system supplied by Stiebel Eltron was installed. The system comprises of the following:

2x heat pumps
5x 1000L hot water tanks (with electrical backup)
1x Control panel with remote monitoring and SMS alarm functionality.
2x booster pumps to feed the hotel with water during times when municipal supply is shut off

The installation has been achieved in a 3 week period. All works have been carried out with minimal interruptions to the hot water supply to the hotel. Remote monitoring of the plant in included to assist the client with possible troubleshooting, thus avoiding unnecessary trips to Lüderitz. SMS communication allows the quick reaction times of hotel maintenance personnel to act in cases of municipal water loss.

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

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 has electrified two schools in remote northern Namibia funded by the Hanns Seidel Foundation with the aim to provide electricity for lighting, thus extending learning hours for learners well into the night. Both systems are based on BlueNova 4kWh lithium ion batteries, Victron Energy charge regulators and inverter technology. Remote monitoring is possible via the integrated Colour Control GX from Victron. Special attention has been given to the system configuration to prevent total battery shutdown. This is achieved by switching the inverter off at a predefined battery state of charge (typically 20%) and only reactivate the inverter once the batteries are charged beyond a predetermined threshold.

The systems where officially inaugurated by the Ambassador of Germany in June 2018.

CTS was approached by a senior resident of Klein Windhoek to install a grid-tied photovoltaic system with the aim to cut back on the monthly electricity bill. The system included:

• 42x 130W photovoltaic modules and mounting structure
• 1x 6kW grid tied inverter

The system is designed such as to generate an estimated 900kWh per month.