HVAC refers to Heating, Ventilation and Air Conditioning. An HVAC system is used to provide desired heating, air circulation and cooling in homes, motor vehicles and air planes among others to the end user’s comfort, in tandem with acceptable indoor air quality.

Bare ceiling with air duct, CCTV, air conditioner pipe and fire sprinkler system on white ceiling wall. Air flow and ventilation system. Ceiling lamp light with opened light. Interior architecture.(istock)

HVAC Systems ensure that the indoor environment is maintained at conducive levels in which individuals and equipment that requires specific storage and operating temperatures are sustained. In a facility set up and rooms, pollutants, odor and bacteria are reduced by use of a well set ventilation system.
An HVAC system in addition improves the quality of indoor air in circulation, ensuring that the air inside is well filtered and clean, almost free of dust, pathogens and germs.

The process of creating, controlling and maintaining desired temperature, humidity and air purity in indoor spaces, independent of outside conditions is defined as air conditioning.

It is a machine that is used systematically for air conditioning.


    Split type air conditioners have two components; an indoor unit and an outdoor unit. Examples of split type air conditioning units are:
Air conditioner condenser outdoor unit (istock)

Wall Mounted Air Conditioners: The indoor unit is placed on a wall, close to the ceiling(on a high level) and are ideal for offices, living rooms and server rooms. The outdoor unit is placed at a place the installer sees fit to allow for pipping works as well as drainage system. The installer chose the wall that ensures even distribution of air.

Air conditioner indoor unit(istock)

ceiling Cassette Air Conditioners: the indoor unit is mounted on the ceiling , with the outdoor unit placed outside of the building. These Ceiling Cassettes turn to cool a wide area and do not take Much space are preferred most in banks and office spaces. They add beauty to the space in which they operate.

White ceiling mounted cassette type air conditioner for large rooms, exhibition room, for business use(istock)

Under Ceiling Air Conditioners: these come with a design that enable them to lift air in a vertical manner into the indoor unit and release the conditioned air horizontally along the ceiling. Another designs allow for air release from it’s four sides.

  1. SINGLE UINT (MONO-BLOCK) AIR CONDITIONERS: These type do not have an outdoor and indoor unit, rather, the the two are merged as a whole (one single unit).

Examples of single unit air conditioners include:

Window Mounted Air conditioners: A square whole fitting the size of the air conditioner is created and the air conditioning unit is installed with the front end facing the inside and the rare end facing outside of the building.

Window mounted (Photo Credit: Mark Walton)

Portable Mobile Air Conditioners: These do not require any mounting structures and are directly placed where the conditioned air is required. They are usually used for smaller applications.

Some air conditioners are designed to run on single phase power whilst some are designed to use three phase power. Based on the power supply available and the nature and how big the room is, an air conditioner has to be selected that will meet the desired needs. Some ceiling cassette air conditioners do require three phase power to run the outdoor unit and single phase power to run the indoor unit.

BTU stands for British Thermal Units. BTUs number indicate the amount of heat an Air Conditioner can remove from a room. The smaller the room, the smaller the BTUs number and the larger the room, the higher the BTUs number.

Air compressors installed in the factory (istock)


Having the right tools comes in handy when executing a particular given job. Each and every profession has its own designated tools to ensure that tasks at hand are done in efficient and effective manner, professionalism attribute.

Working Contractor Electrician. Fixing the Light.

For Electricians, technicians and DIY, here with are the must have tools;

This is a device used to measure electrical quantities such as voltage, current and resistance. The most commonly used are digital multi-meters which measure multiple electrical quantities such capacitance, diode test, DC and AC voltage, resistance and continuity. There are different types digital multi-meters and one of the top brand is fluke. https://www.fluke.com/en/products/electrical-testing/digital-multimeters

Another brand you can go for but not limited to is Amprobe .https://www.amprobe.com/product-category/multimeters/digital/

Typically, pliers are used for cutting wires, stripping the insulation part (outer coating) of a wire and joining two wires that have their insulation part stripped off to a given length by taping them or using a connector block. Pliers are also used for twisting, bending and gripping wires and cables.
Some of the brands used but not limited to include;

A screwdriver is a tool used for tightening and loosening screws. They are two main types; Flat and star screwdriver. Screwdriver sets are of different sizes ranging from terminal small ones to big ones depending on the size of stew involved.

Also known as a Hex key, Allen key is used for loosening and tightening bolts and screws that have hexagonal shaped sockets atop. The L shaped Allen keys are commonly used for most electrical applications.


Fish tape is a tool used by electricians when wiring a building and or a house. It used to pull wire through electrical conduits.


A pipe bender is a tool used when bending pipes for electrical conduits. A bender alters the shape of the pipe, PVC commonly used, to ensure the continuity of the pipping conduit with the desired angle of bend.

A drill machine is a tool used to for drilling(creating) holes on hard surfaces such as walls, wood using drill bits. Depending on the task at hand, different drill bits are used. For concrete walls, concrete drill bits are used and for metal surfaces, metal drill bits are used. Saw cutters are also used when creating holes such as those for cable glands on a metal surface.


A hacksaw comes in handy when cutting cables, especially armored cables and also pipes for conduits to length. Its a too used for cutting purposes, using the blade attached to it.

Mostly used when cutting electrical insulation, stripping off cable insulation, cutting cables and electrical tape.


A crimping to is mainly used when joining a wire to a lug in such a manner that a wire connected to a lug or a connector is deformed making a joint in the process. There are three types of crimping tool;hand crimping, hydraulic crimping and hammer crimping.

Hand press crimping tool
Hydraulic crimping tool

An electrician uses a hummer mostly during wiring and electrical installation. A chasing hammer is used when creating channels where pipes for conduits are laid. The ball shaped side is used for hunkering saddles to hold the pipes to the surface. The ball side is also used to ensure that electrical fittings such as round boxes and square boxes are held in place, by driving nails attaching them to the wall surfaces or trusses.

Chasing hammer with comb

A tape measure is useful in determining the length of a particular subject matter. It can be used to determine the height of a socket, switch, cooker control unit as well as length of a cable for accuracy, avoiding wastage. It ensures uniformity in installation of electrical fixtures as accuracy is guaranteed.

Insulation tape has to be available st all the. It is used to insulate cable joints where connector blocks are not available. It is also used to insulate electrical wires whose insulation has suffers wear and tear. When cables have been isolated, insulation tape comes in handy so as to ensure that no wire is bare,in so doing avoiding accident s and electrical shock.


Smallholder farmers contribute about 60% of the global food produced. In most parts of the world, these farmers rely on rain fed farming, a scenario that leads to one growing season in a whole year. This results to low productivity for the farmers as they have to wait for the rainy season in order to grow their crops.

Countries that have succeeded in agriculture and food production have prioritized irrigation in their farming activities, ensuring an all year farming season, supplementing periods of no rainfall.
For more sustainable agri-food systems, irrigation has to be incorporated, ensuring water availability all year round. Sub-saharan African countries have good arable land, suitable for farming and able to support the growth of different crop varieties as well as water bodies and sources which can be utilized for irrigation.
In as much as irrigation farming is key in ensuring food security, all year farming and zero hunger, choosing the right pump for your needs is the prerequisite.
In selecting a pump for your farming activities, you have to:

    Knowing your water source is key in determining the type of water pump to be used. Water can be sourced from a river, stream (surface)and a drilled borehole(underground).
    Basing on the crops being grown and other activities requiring water, total daily water demand has to be calculated.
    for surface water sources, surface water pumps are ideal, and for underground water source, submersible pumps are to be used. Submersible pumps are mainly submerged in drilled boreholes with water piping system connected.
    It is important to find out the flow rate of the well in submersible water pump systems, which is the amount of water flowing through the pipe connected to the pump at a given time span and can be calculated in Liters/second or Liters /minute or cubic meters per hour.
    The to talk dynamic head is calculated by determining the distance from surface to water level when pumping, the pressure at pump discharge and drops pipe friction as well as valve(s).
    For water storage purposes, tanks are used. In such a set up, water is pumped into the funk which usually rest on an elevated flat surface and then distributed to the farm using gravity force. It is recommended that you use a pressure tank in order to build the pressure of the water being delivered.
Solar powered pump

Look out for the next blog on how to size a solar water pumping system and the available solar water pumps.


House roof with solar panels

The global Energy mix has experienced a rise in production and use of Renewable Energy Technologies, with solar power equipment topping the list. Notable companies and organizations are going green, opting for solar energy as the main source for power in their office buildings and equipment there in. This is in line with the Sustainable Development Goal number 7:Affordable and Clean Energy. Not only big companies are replacing their Diesel/petrol powered generators With solar powered systems but also home owners are opting for the new, clean source on energy for their power needs. A solar photovoltaic system can be used either as backup, or stand alone system powering a house or used for irrigation and water pumping.

Of late, many home-owners have raised the reliability of solar home based systems with the main concern being that the system does provide power for a few hours and goes off, and in a Sub-Saharan Africa set up, it turns not to fulfil the desired backup Electricity when the grid goes off during load shedding and in villages where access to electricity is but a dream to many.

But what really causes the system not to perform to its full capacity as desired by the user?

Solar Home System

Lack of qualified personnel in sizing, designing and installing solar home systems is the main reason. Most proprietors fot Solar Home systems are only interested in making the sale and at the same time, a majority of home owners are excited about having solar powered electricity installed without taking Considering the factors that will contribute to the effective and efficient performance of the system, and as a result, the system is under-sized and people turn to look down on solar power.

So what are the factors that one has to consider to get a Solar Home System with optimum performance?

  1. Energy Audit
    To avoid being deceived, a customer(home-owner) must be able to calculate the amount of electricity in Kilowatt hours(Kwh) used each month and in a year. After that, power rating for each appliance has to be recorded to find out which appliance needs more power and which one has the lower rating.


Once the Energy audit is done, a customer must now have a clear picture as to which appliances consume alot of electricity based on the power rating and the time in hours those appliance are in use and which appliances do not consume alot of electricity. This forms the basis in selecting the appliances that can be connected to a solar home system. As a customer, it is important to note that the initial cost for a solar home system is high and so, determining and selecting critical appliances and loads to be powered is vital. One can start small and and add loads(appliances) to the system by increasing its Generation and output capacity to match the additional loads power demands.

Reaching this far, a customer is now in a position of choosing which appliances to use, and for how many hours per day to be powered by the solar system. A qualified personnel has to be engaged to help the customer come up with the optimum solar home system solution.

The customer has to select the loads to be powered by the system and the number of hours the selected appliance will be used in orde to come up with the total daily energy demand. Once this is calculated, the designer then using the Current rating parameter of the solar panels available comes up with s figure for the number of panels required for the appliances selected. Since solar panels produce DC voltage, an Inverter is required to convert DC voltage to AC voltage which most home loads/appliances use. The system also requires a charge controller that regulates the amount of charge going to the battery bank so that the batteries do not overcharge. It must be noted that some inverters do have built in charge controllers.

Night fall, what Happens?
Solar power is dependent on availability of the sun.
In-order to have uninterrupted power supply at Night, a batter bank has to be in-corperated to store the electricity produced during the day. Clarity must be made during system design calculations in-order to store and get enough power to be used at Night for the specified number of hours.

Only those appliances/loads selected during the system design should be used and connected. if appliances not specified during the selection stage are plugged in, more power is withdrawn and so, can only sustain the system for a few hours less than those used during the design stage and so the system fails as more power is being consumed that it is being produced. In cases where new appliances are to be introduced, the customer has to consult the system designer so that it gets upgraded to match the new electricity needs.


21st century it is, and despite an upsurge in
electricity access as well as the development of technologies that generate electricity, nearly 573 million people in Sub-Saharan Africa are yet to access electricity, the largest access deficit globally. With most families living on almost a dollar per day, electricity is viewed as a luxury on their priority list since the cost is high as compared to conventional energy sources, yet to foster economic growth and sustainability, electricity plays a major role. Electricity is not an end in itself but a means to an end in various sectors such as health, industry and manufacturing among others.

Net metering

The introduction of Inclusive business models, policies and incentives that promote use of Renewable Energy technologies has seen an increase in use of products such as solar panels for electricity generation in areas with low access to electricity.

In Sub-Saharan Africa, low generation capacity is the major challenge in ensuring that households are connected to the national grid. Though governments have implemented the Rural Electrification Program, the focus is on the trading centers with proven economic activities and not actual households per say.


In addressing inadequate power generation capacity, Sub-Saharan countries have resorted to
Independent Power Producers, using power purchase agreements to boost the power available in the National grid. An independent power producer (IPP) or non-utility generator (NUG) is an entity, which is not a public utility, but which owns facilities to generate electric power for sale to utilities and end users. NUGs may be privately held facilities, corporations, cooperatives such as rural solar or wind energy producers, and non-energy industrial concerns capable of feeding excess energy into the system.


The coming in of IPPs has benefited Sub-Saharan countries not only in improving grid stability but also, introduction of mini grids that are supplying electricity to a designated rural area and village, creating a Decentralized energy system.

The least expensive way to achieve universal electricity access is through use of renewable energy sources. Renewable energy grid connected
systems have the potential to deliver affordable and clean electricity access to millions, coupled with stand alone photovoltaic systems. Decentralized solutions as a whole are the least-cost way to provide power to more than half of the population gaining access to electricity.


Imagine every household in sub-Saharan Africa having its own power generating unit, a rooftop with solar panels with a battery bank, and being able to sell excess power generated to the national
utility grid, using net metering and grid tie solutions. Im as much as access to electricity can increase, economic growth can be fostered as households will be able to make money as power producers.

Net metering is a system that allows domestic or commercial home owners who generate their own electricity using solar panels to sale their surplus electricity generated back to the national grid. a rate has to be agreed between the utility provider and the home owner.Then, at night or other times when your solar panels are under-producing, you pull energy from the grid and use these credits to offset the costs of that energy.

How Net Metering Works

Net meters work in that they generate data on how much electricity is being generated and how much electricity is being consumed at that household.
The data is then accumulated in the appropriate register over the billing cycle and the bill is calculated basing on the rate agreed.
Under net metering, the electricity generated by your system and consumed in your home, you pay nothing for this electricity. Whenever the solar power system generation exceeds your homes consumption, this excess amount is exported to the grid and you may earn a feed-in tariff for this exported solar electricity. Check your energy retailers solar feed-in tariff policy.

Taking advantage of power inter-connection agreements, Sub-Saharan African countries can benefit alot from net metering options in ensuring the available of a regional stable grid whilst empowering citizens economic wis


food Safety

A Food Safety Management System has to have a system that enables the identification of Product lots with respect to the batches of raw materials, processing and delivery records. in order to do so, a business sets a traceability system for such.

An effective traceability system has to be able to identify incoming material from the suppliers and the Distribution route taken, process flows involved up to the end Product. It is therefore required that the records for traceability be kept and maintained per adventure there is Product withdrawal or unsafe products handling. This ensures that the actual raw materials used for that production batch are tracked effectively so that only that affected batch is withdrawn.

In cases where products do not conform to the set standards, measures have to be set in order to ensure that the system runs according to set standards. This is the control of nonconforming products. There are two ways of controlling nonconformity:

when critical limits for Critical Control Points are exceeded, or in cases where there is loss of control of Operational prerequisite programs, affected products have to be identified and controlled in accordance to their use and purpose. Well documented procedures have to be set, with details on how they are identified in order to ensure that they are handled properly. For such, colour codes are sometimes used to mark the affected end products.


Corrective actions are initiated when critical limits are exceeded or when there is a lack of conformity with the set Operational prerequisite programs. a business sets procedures that specify the pertinent actions in order to identify and eliminate the cause of nonconforming products, so as to prevent the repetition, and also, restore the system back to control to avoid further nonconformance. The actions include but are not Limited to:

  1. Review of nonconforming products
  2. Determining causes of nonconformities
    3.setting required actions to ensure that nonconformities do not occur
  3. keeping records of the corrective actions taken

A Business has to take action on all nonconforming products so as to ensure that the products do not enter the food supply system and market. as such, the business has to ensure that before entering the food supply system,

1.Food Hazards connected to the nonconformance are reduced to the acceptable levels. for example, Aflatoxin levels, in groundnuts

  1. Associated food safety Hazards are to be reduced to appropriate acceptable levels identified before entering the food supply market.

In cases where products leave the control of the the business and are on the market, and still, are determined to be unsafe, the business has to notify all stakeholders and initiate s Product recall or withdrawal. this has to be documented for record purposes.

After the recall, there is need to evaluate the Product batch in-order to find out whether reprocessing or reworking reduce and or eliminate the Hazards and so certified as acceptable.

If the product lot is not acceptable for release on the food supply market, even after reprocessing, then it has to be destructed or disposed off as waste.


Power Station Schematic

Hydropower is the most common and widely used renewable resource for generating electricity. The electricity produced varies, ranging from as small as KW to GW which is large. The worlds’s earliest electricity distribution in 1818 was generated using hydro turbines whose rated capacity was in KW, and by 2008, hydropower capacity had rached about 874GW. As of date, There is more than 1,300G of installed hydropower capacity globally.
According to the International Renewable
Energy Agency (IRENA)’s Global Renewables Outlook 2020, this figure will need to grow by around 60 per cent by 2050 to help limit the rise in global temperature to well below 2 degrees
Celsius above pre-industrial levels. Such growth would help generate some 600,000 skilled jobs over the coming decade according to IRENA and would require an estimated investment of US$1.7 trillion.

Power generated by converting the potential energy of fast flowing or falling water and kinetic energy to mechanical Energy using a turbine. When the turbine is coupled to a generator, hydroelectricity is produced. Hydropower output depends on annual rainfall, water catchment and,of course, installed capacity.

In Africa, hydropower is the main renewable resource with over 37GW of installed capacity. Though i has the highest untapped potential in tje world, only 11% has been utilised, with an annual growth rate of 4.4% in the last 10 years.

Climate related effects are very high in Africa as compared to other continents, despite the fact that the continent produces a very minimal percentage of the global CO2 Emmissions as a result of electricity generation, thereby impacting hydropower generation and capacity.

The Three Gorges Dam is the world’s largest capacity hydroelectric power Station. It has 34 generators, with 32 of them being the main generators with each having a 700MW capacity. The two other generators are plant power generators, and each has a capacity of 50MW. This makes the Total capacity to be 22,500MW.

The Three Gorges Dam

There are two types of turbines; Impulse turbine and Reaction turbine. Impulse turbines are built in such a way that water flow hits the turbine as a jet in an open environment with the power originating from the kinetic energy of the flow. Reaction turbines work whereby the turbine is totally embedded in the water and powered from the pressure drop across the turbine. The commonly most used reaction turbine is called Francis turbines, and it incoperates a runner in its principle of operation to allow the water push conyinuously against the blades aided by stay veins and guide vains.

Cross section of a Francis Turbine


RENEWABLE ENERGY:SOURCE – Hydropower – Solar – Wind – Geothermal – Biomass – Hydrogen – Ocean/Tidal

HYDROPOWER; Power generated by converting the potential energy of fast flowing (kinetic energy) or falling water to mechanical Energy using a turbine. When the turbine is coupled to a generator, hydroelectricity is produced.

Water intake dam for hydropower generation

SOLARPOWER; Energy produced from the sun’s radiation and converted into useful thermal heat using solar collectors or electrical energy using solar panels.

WINDPOWER: Power generated by converting the kinetic Energy of wind to mechanical power (water pumping) or electricity using Wind turbines.

Wind turbines

GEOTHERMAL ENERGY;Energy produced by harnessing the heat trapped beneath the earth’s surface for electricity generation, hot water supply and heat pump applications.

BIOENERGY BIOMASS ENERGY; Energy derived from plant and animal material with their wastes and residues. BIOFUEL;Transformation of the initial material by chemical and biological processes.(methane gas,briquettes)

TIDAL ENERGY; Power Produced by harnessing the tidal flow and tidal range of tidal currents at specific locations, in coastal and inter-island channels.

Newly constructed tidal power generating turbine mounted on a test platform.


who are my customers? How does my business make money? what is my value proposition?

These are some of the questions most start up entrepreneurs struggle with and spend a lot of time figuring out. At the same time, potential investors do look for Answers to these questions, which in-turn act as a basis in finding out how Investment ready a business is.

one tool that helps start up entrepreneurs find Answers to their most pressing questions in turning their business idea to a working business model is the Business Canvas Model, also known as the Lean Enterprise Blueprint. The Model encompass the why, how and what of the business at hand.

The key business aspects to consider in answering the pressing questions and generating a Lean Enterprise Model include:

The problem your product or service seek to solve has to be clearly defined, be it access to Clean energy, portable water or value addition to agro produce. Evidence must show that there is a pressing issue indeed in that area you seek to solve with your product, taking into account other alternatives available.

A straight to the point statement on how you seek to solve the problem is key in driving the message home. it has to tackle how the product or service fits in solving the problem.

This section entails how unique your product or service. What makes it stand out from the rest being offered for the same problem you seek to solve.

A picture of how will the business make money is what is required in this box. be it customers paying for a product or a service, or a subscription fee per month or quartely, but an estimate atleast has to be provided.

be it human resource, machinery office space, factory building, this segment is for all key resources that will enable you deliver the service or manufacture the product to get the uniqueness desired.

all expenditures involved have to be well taken into account. this includes cost of raw materials, utility bills, machinery, distribution.

This segment enables you to have a clear picture of who your customer is. People will like your product or service but a segment will be willing to pay for it. As an Entrepreneur, you have to analyse those who will pay for your product.

Distribution is key in getting the product to customers, otherwise the business will not take off at all. You have to point out how the product will get to the customer either directly, or via channles such as retailers and wholesalers or via the internet.

The business canvas Model provides an entrepreneur with this segment where organisations, suppliers and other businesses you need to work with in order to make it are listed.

This involves what goes into the final product or service provided. That is, the flow diagram, or steps from input, process steps involved to deired output, raw material to processing to final product.

In addition, an entrepreneur has to take note of the social corporate responsibility, job creation and livelihood improvement as well as environment protection an zero carbon emmissions in generating a Lean Enterprise Model. The model leaves room for reworking, refining and continuous improvement.


Solar Panels in Atacama Desert, Chile

PHOTOVOLTAIC (PV) GENERATION:- The production of power caused by photons of electromagnetic radiation separating positive and negative charge carriers in absorbing material. Semiconductor technology field where sunlight is converted to Electricity.

SOLAR PV CELL:- Component that generates Electricity by using light energy from the sun, producing electrical current.

SOLAR PANEL:- Sometimes called Solar mbodule, is a single photovoltaic panel on which solar PV cells are assembled and connected. (connection in series to increase output voltage).

SOLAR PV ARRAY:- Arrangement and connection of solar panels that generate electricity as a whole/system. (specified amount of Electricity in KiloWatts).

SOLAR STAND ALONE SYSTEM:- A solar system that uses a solar panel or a solar PV array to provide Electricity during the day and coupled to a battery bank that stores power produced and can be utilised by the electrical loads connected.

SOLAR FARM:- Large scale solar PV array installation that functions as a solar power station and can be used to provide off grid electricity to a village/community/rural area/factory or can be connected to the national grid system.