Photo-voltaic, Frequently Asked Questions

  1. ’’’What is Solar Energy?’’’ Solar energy takes advantage of the sun's rays to generate heat or electricity. It is an infinitely renewable resource and unique for its ability to generate energy in a quiet, clean, and consistent manner. It is also excellent for remote, ‘off grid’ locations.
  1. ’’’How do solar photovoltaic cells work?’’’ In layperson terms, photovoltaic cells are comprised of a semiconductor material such as silicon. Added to the silicon are the elements phosphorous and boron which create conductivity within the cell and activate the movement of electrons. The electrons move across the cell when activated by the sunlight's energy into the electrical circuit hooked up to the solar panel.
  1. ’’’What is the difference between solar panels, and building integrated photovoltaic (BIPV) products?’’’ Solar panels are flat panels of photovoltaic arrays mounted on a roof or a pole to capture the sun's rays. Building integrated photovoltaic materials are PV arrays that are integrated into the building material itself, primarily windows, roof tiles, or walls. Solar panels work well for retrofits or remodels while BIPV are appropriate for new construction or a major renovation.
  1. ’’’How much will I really save on my utility bills from a home electric solar power system?’’’ Of course this is a relative question. It depends, in part, on how much electricity you use and how efficient the appliances are that you operate. That said expect to generate excess electricity in the summer which can potentially offset the energy you use from the grid in the winter. A combination of energy efficient appliances and light bulbs can help reduce your homes energy bill by over two-thirds.
  1. ’’’What is the difference between solar voltaic and solar hot water systems?’’’

While both types of solar systems capture energy from the sun, solar photovoltaic systems use photovoltaic panels to produce electricity. Solar hot water, or thermal, systems capture sunlight to heat water for domestic use, to heat a swimming pool, a radiant heating system, or air conditioners.

  1. ’’’What are solar hot water systems?’’’ Solar hot water systems, broadly termed solar thermal systems, use the sun's energy to heat water. Solar hot water systems can be used to heat a hot water tank or to warm a home's radiant heating system. Swimming pools and hot tubs use a modified solar hot water system for heating water.
  1. ’’’How do pool heating systems work?’’’ Pool heating systems use a modified solar hot water system to capture the sun's rays to heat your pool or hot tub.
  1. ’’’Can I use solar power to heat my home?’’’ Absolutely! Radiant heating applies solar thermal technology. Transferring solar energy through pipes into an under floor radiant heating system is a wonderful way to stay warm. Radiant floor systems are typically 40 percent more efficient than their forced air counterpart and can be zoned to match thermal comfort to each room.
  1. ’’’How much maintenance do solar energy panels require?’’’ Solar photovoltaic panels require little maintenance - no need to wash or dust. It is, however, important to place panels where they will remain clear of shade and debris. Thus you will have to wipe them off if leaves fall on them. Solar hot water collection arrays don't need much attention either. It does help to periodically use a window wash brush, soap, and water to clean the tubes.
  1. ’’’Do I need special insurance requirements for my power system?’’’ Standard homeowner's insurance policies usually suffice, however it is important to discuss this with your insurer.
  1. ’’’When should I see a solar professional?’’’ Although solar energy systems work in parallel with conventional residential electrical and plumbing systems, with Zimbabwe’s infrastructure, and local conditions, it is always wise to ask questions of those with experience.
  1. ’’’What should I ask?’’’ Experienced installers can take the guess work out of installing a solar power system. Whether you are considering solar photovoltaic or solar hot water, a solar professional can help you determine the type and size of system that will work best and guide you through the process.
  1. ’’’How can I calculate the cost and payback time from a solar power installation?’’’

Determine your current energy needs and costs and compare against your future anticipated use. Once you have a sense of how much energy you use, you can find the cost of purchasing and installing one or both of the technologies. Compare these two. In addition, in Zimbabwe, there are factors besides pure cost. Convenience and reliability are two.

  1. ’’’How long will it take to install a solar power system?’’’

Planning, configuring, and doing any custom ordering for your solar energy system can take up to a few weeks. However, the installation process itself can typically be completed in days.

  1. ’’’How many solar panels do I need for an electric solar power system?’’’ The size of the system is correlated to your home's energy-use needs. An energy audit is needed. Record how many kilowatt hours you use in a month, and work back from that point. If you are installing a solar geyser at the same time, your electricity use will also change.
  1. ’’’How much shading is too much for solar photovoltaic panels?’’’ Unfortunately shading a photovoltaic system dramatically decreases its output. Just shading the bottom row of wafers alone amounts to an 80% reduction in efficiency. So above all, don't shade your array!
  1. ’’’How do I know if solar panels will work on my home?’’’ Take a look at the position of your home on its lot - and particularly your roof. And shade. Ask the following questions: Is there good “Northern” exposure? - Orienting solar panels to the North maximizes the effectiveness of energy collection. Is the exposure free of trees or buildings that could shade the panels or drop debris on them? - Shading photovoltaic panels dramatically reduces their effectiveness. What is the pitch of your roof? - Most roofs, from flat to 60-degrees can accommodate photovoltaic panels.
  1. ’’’Do I need to have North facing exposure to have a solar energy system?’’’ No. Although Northern exposure increases the effectiveness of a solar power system, your site will still work for solar power without having the North facing exposure if it receives any sunlight. In Zimbabwe, a tropical country, the sun is directly overhead for many months. The number of panels required for full winter will increase depending on exposure.
  1. ’’’What other factors are important to consider when installing a home energy system?’’’ The location of your site and the local climate will play into where you place and how you install your solar electric or solar hot water system. Wind speeds can affect a solar array. Understanding how those inputs effect performance will determine the types of mounts or how the arrays are angled. Ask someone with experience.

Further reading