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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.

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.

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.

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

National Botanical Research institute approached CTS to upgrade two of their existing AWS to satellite communication and subsequent installation at Kanovlei in the Tsumkwe Area as well as Koichab Pan close to Lüderitz.

Communication is via Meteosat satellites and based on a “fire and forget” principal which unfortunately does not allow remote maintenance procedures.

The stations form part of the SASSCAL Weathernet and measure all important meteorological parameters.

Weather data can be viewed at: 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