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The installed photovoltaic system at Elavi Clinic caters for the power supply to the clinic as well as the nurse houses. A 6.2kW PV module array generates enough power for the energy requirements. Should this not be sufficient the batteries can be charged by a backup generator.

The system consists of the following:

• 6.24 kW PV array
• 2x Victron BueSolar 150V/70A MPPT regulator
• 600Ah Battery capacity
• Inverter/Charger, Victron Multi, 48V/8000VA
• System Monitoring (BMV700, Color Control GX)

CTS was awarded four tenders in 2015, to supply, deliver to site, install, test and commission of autoclaves throughout Namibia.

In addition to the 160L Steri Tech autoclaves, water softeners were installed to increase the life span of each unit and reduce overall maintenance cost.

A number of installation teams worked hard to complete the project within the stringent timeframe set by the client. Each site came with its own challenges such as:

1. Removing of existing units that were beyond repair
2. Low supply water pressure
3. Space limitations where the new units were to be installed
4. Breaking out of walls to fit new autoclave
   

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.

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

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.