Consider energy-efficient buildings


Incessant power outages continue to haunt the country.

As the dry season holds, the water levels in the Shire River dwindle– significantly lowering the output of Electricity Generation Company (Egenco) output in the process.

Over the years, this problem is becoming ever more distinctively seasonal.

This trend is not only unsustainable but also works against the country’s development.

The urgency to keep it in check cannot be overemphasised.

Ideally, increasing production through major infrastructural investment should be the solution of choice.

Considering the intricacies of registering such a long term commitment as this one would be, it may be important to explore means of ensuring that the available power is put to use in an efficient manner at all cost.

A quick starting point of exploration would be the building industry.

Research has shown that buildings consume significant amounts of energy, about 40 percent of the available final energy.

As standards of occupied building space continuously go up, so does the buildings ‘energy consumption’.

This energy goes towards heating, ventilation and air-conditioning, domestic hot water heating, food preparation, refrigeration, lighting, electronics and others.

If the country found a way of ensuring efficiency in the buildings’ energy consumption, some power would be saved and the outages would at least be fewer and far apart.

Elsewhere, there are building energy codes to ensure the efficient consumption of energy in buildings.

Studies have shown that these codes can yield up to 30 percent in energy savings.

Building energy codes constitute enforceable minimum requirements for energy-efficient design and construction of new and renovated buildings. Typically, such codes cover several aspects, including the outer shell of the building and the services.

Codes ensure that the building is designed and constructed in such a way that the building interior environment is maintained at acceptable conditions with the usage of very little to no energy at all.

The amount of heat, air and moisture allowed to pass through the building envelope is carefully regulated by the codes.

A reduction in the amount of heat passing through the envelope into the building interiors translates into a reduction in the amount of energy consumed by an air-conditioning unit to cool the space.

Building services refer to all such amenities that are added to the building structure to enhance its habitability.

The services of particular importance to energy consumption include heating, ventilation and air-conditioning as well as hot water heating.

The codes set minimum energy requirements for these systems. In most instances, compliance forces the designers to exploit local site conditions in reducing the services’ energy consumption.

In this way, they may consider coupling natural ventilation with mechanical ventilation instead of just using the latter. This saves energy.

They may also consider employing natural lighting and hot water heating instead of active energy consuming systems.

Intelligent systems may also be called upon. These automatically control services, supplying them with energy only when need arises.

Presently, a lot of energy goes to waste in the country’s buildings, especially in banks and government offices whose energy consumption is already inherently higher than in homes.

In these buildings, whose outer shells are not insulated, air-conditioning system sizing and design is not appropriately done.

For the most part, a contractor will just buy the air-conditioning units off the counter and install them without undertaking any calculations for the heating and cooling requirements.

This leads to unnecessarily oversized systems.

Sometimes, windows and doors into air-conditioned spaces are left open while the air-conditioning unit is on, This unnecessarily overburdens the system. Electric lights remain switched on during day time due to inadequate natural lighting. n

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