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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.

Based on our excellent service and knowledge we have rendered to the Botswana Meteorological Department as well as University of Hamburg, CTS was able to secure the 2nd Phase of the manufacture, supply and installation of automatic weather stations in Botswana.

The stations supplied to make use of satellite communication due to the extreme remoteness of the sites, these were:

• Mababe (Savuti Marsh)
• Tubu (Okavango)
• Baines Drift (Eastern Botswana)
• Xade (Central Kalahari Game Park)
• Ngwaltle (Western Botswana)

These stations are not located at any Meteorological Department property, thus fences had to be erected for protection against animals.

Station design is based on our well proven tripod mast with all relevant sensors and a CR1000 logger as the processing unit. Data is transmitted at fixed timeslots allocated by EUMETSAT (Germany) on an hourly basis. Satellite transmission is based on a fire and forget principle, thus no remote maintenance can be done.

Weather data can be found at: http://www.sasscalweathernet.org .

CTS was approached by the Botswana Meteorological Department and the University of Hamburg with the request to install automatic weather stations across Botswana. A total of 10 stations were engineered and build at our workshop in Windhoek prior to installation commencement. With our own tower design, the installation time is reduced to nearly 8 hours per tower.

The stations are equipped with sensors from Vaisala, Kipp and Zonen. At the heart of each station is the CR1000 logger from Campbell Scientific. Each station is capable to measure the following:

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

In addition to the above parameters the following parameters are calculated by the logger by means of mathematical models.

• Dew point temperature
• Wet bulb temperature
• Sunshine duration

The data from the station is transmitted to ftp servers situated in Gaborone/Botswana as well as Hamburg/Germany on an hourly bases over locally available GSM network providers. Once the data is uploaded to the server in Hamburg, it is processed and posted on a publicly available website. This website collects data of numerous stations across Namibia, Botswana, Zambia, Angola and South Africa for research purposes. A total of 8000km was covered in just under 4 weeks.

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.

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

When A La Mer Hotel in Swakopmund decided to expand, they approached CTS with a unique challenge: to create a functional laundry that was both energy and water efficient, and would also fit into a small space, while being whisper quiet, so as not to disturb any guests. In addition, the laundry has to perform excellently, producing quality wash, tumbling and ironing results. Only one brand came to mind: Miele.

Miele recently launched new bench mark machines, which have short program cycles, excellent spin performance, a redesigned patented honeycomb drum and have low consumption values. A La Mer Hotel was the first in Namibia to purchase these new machines.

CTS installed washer extractors with water recovery units, as well as automatic dosing systems, to ensure the best quality wash, every time. The tumble drier has an air recycling system, saving up to 60% of energy. And with a matching drying ironer, optimum finishing results are achieved. Small accessories made this laundry a complete turn key solution.