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Various small off-grid PV systems, also referred to SHS (Solar Home Systems) have been supplied country wide. These systems are typically based on small high efficiency lithium ion batteries as storage solution and Victron components such as solar charge regulator, inverter and monitoring devices.

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.

The University of Hamburg approached CTS directly with the request to quote and subsequently manufacture and install 3 automatic weather stations at:

• Khorixas
• Kaoko Otavi
• Okangwati

Once again, satellite communication has been chosen, this time not because of GSM not being available, but to reduce future cost of the stations as satellite communication for these stations has got no costs associated.

In addition to the basic data measured:

• Wind speed
• Wind direction
• Humidity
• Air Temperature
• Irradiance
• Barometric pressure
• Ground Temperature
• Rain
• Leaf wetness

The stations are equipped with a WLAN interface. This allows the connection of 49″ SmartTV to be connected to each station to display the current weather inside close by offices.

A modern hot water plant was installed based on heat pump technology. Stiebel Eltron storage tanks as well as heat pumps are supplied that are extremely energy efficient and long life expectancy while at the same time low on maintenance. Further energy savings are achieved as the system is connected to heat recovery units as part of the refrigeration plant.

The challenge of such a system is to guarantee even loading and unloading of the tanks with water to guarantee a uniform temperature distribution in all tanks. This has been achieved by careful piping planing based on the Tichelmann principal.

The system comprises of the following:

• 6x 1000 L buffer tanks
• 2x 23kW heat pump units.
• various pumps and control unit

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.

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.